package main

import (
	"bytes"
	"context"
	"crypto/rand"
	"crypto/sha256"
	"database/sql"
	"encoding/base64"
	"encoding/hex"
	"encoding/json"
	"errors"
	"flag"
	"fmt"
	"io"
	"net/http"
	"net/url"
	"os"
	"os/exec"
	"path/filepath"
	"regexp"
	"strconv"
	"strings"
	"time"

	"github.com/go-sql-driver/mysql"
	"golang.org/x/crypto/bcrypt"
)

const (
	defaultServerURL = "http://localhost:8080"
	defaultStorage   = "storage"
	tokenTTL         = 7 * 24 * time.Hour
)

var (
	usernameRE = regexp.MustCompile(`^[a-z0-9_-]{3,32}$`)
	repoNameRE = regexp.MustCompile(`^[a-z0-9._-]{1,100}$`)
	branchRE   = regexp.MustCompile(`^[A-Za-z0-9._/\-]{1,200}$`)
)

type User struct {
	ID       int64  `json:"id"`
	Email    string `json:"email"`
	Username string `json:"username"`
}

type Repository struct {
	ID           int64     `json:"id"`
	OwnerUserID  int64     `json:"-"`
	Owner        string    `json:"owner"`
	Name         string    `json:"name"`
	Visibility   string    `json:"visibility"`
	ForkedFromID *int64    `json:"forked_from_id,omitempty"`
	CreatedAt    time.Time `json:"created_at"`
	UpdatedAt    time.Time `json:"updated_at"`
}

type PullRequest struct {
	ID                 int64      `json:"id"`
	Number             int        `json:"number"`
	TargetRepositoryID int64      `json:"-"`
	SourceRepositoryID int64      `json:"-"`
	AuthorUserID       int64      `json:"-"`
	Author             string     `json:"author"`
	SourceOwner        string     `json:"source_owner"`
	SourceRepo         string     `json:"source_repo"`
	SourceBranch       string     `json:"source_branch"`
	TargetOwner        string     `json:"target_owner"`
	TargetRepo         string     `json:"target_repo"`
	TargetBranch       string     `json:"target_branch"`
	Title              string     `json:"title"`
	Description        string     `json:"description"`
	Status             string     `json:"status"`
	CreatedAt          time.Time  `json:"created_at"`
	UpdatedAt          time.Time  `json:"updated_at"`
	ClosedAt           *time.Time `json:"closed_at,omitempty"`
	MergedAt           *time.Time `json:"merged_at,omitempty"`
}

type Server struct {
	db      *sql.DB
	storage string
}

type Config struct {
	Server    string    `json:"server"`
	Username  string    `json:"username"`
	Token     string    `json:"token"`
	ExpiresAt time.Time `json:"expires_at"`
}

func main() {
	if len(os.Args) < 2 {
		usage()
		os.Exit(2)
	}

	var err error
	switch os.Args[1] {
	case "server":
		err = runServer(os.Args[2:])
	case "register":
		err = cliRegister(os.Args[2:])
	case "login":
		err = cliLogin(os.Args[2:])
	case "logout":
		err = cliLogout(os.Args[2:])
	case "whoami":
		err = cliWhoami(os.Args[2:])
	case "clone":
		err = cliClone(os.Args[2:])
	case "repo":
		err = cliRepo(os.Args[2:])
	case "pr":
		err = cliPR(os.Args[2:])
	case "help", "-h", "--help":
		usage()
	default:
		err = fmt.Errorf("unknown command %q", os.Args[1])
	}
	if err != nil {
		fmt.Fprintln(os.Stderr, "error:", err)
		os.Exit(1)
	}
}

func usage() {
	fmt.Println(`gitocean - CLI and server for a small Git hosting platform

Commands:
  gitocean server --dsn DSN [--addr :8080] [--storage storage]
  gitocean register [--server URL]
  gitocean login [--server URL]
  gitocean logout
  gitocean whoami
  gitocean clone OWNER/REPO
  gitocean repo create NAME (--public|--private)
  gitocean repo delete OWNER/REPO [--force]
  gitocean repo search QUERY [--all|--mine]
  gitocean repo fork OWNER/REPO [--name NEW_NAME]
  gitocean pr create --from OWNER/REPO:BRANCH --to OWNER/REPO:BRANCH --title TITLE [--description DESC]
  gitocean pr create --repo OWNER/REPO --from BRANCH --to BRANCH --title TITLE [--description DESC]
  gitocean pr list OWNER/REPO
  gitocean pr view OWNER/REPO NUMBER
  gitocean pr close OWNER/REPO NUMBER
  gitocean pr merge OWNER/REPO NUMBER`)
}

// ---------------- Server boot and migrations ----------------

func runServer(args []string) error {
	fs := flag.NewFlagSet("server", flag.ExitOnError)
	addr := fs.String("addr", ":8080", "HTTP listen address")
	dsn := fs.String("dsn", os.Getenv("GITOOCEAN_DSN"), "MySQL DSN")
	storage := fs.String("storage", defaultStorage, "storage directory")
	if err := fs.Parse(args); err != nil {
		return err
	}
	if *dsn == "" {
		return errors.New("--dsn or GITOOCEAN_DSN is required")
	}

	db, err := openMySQLAndCreateDatabaseIfMissing(*dsn)
	if err != nil {
		return err
	}
	defer db.Close()
	if err := migrate(db); err != nil {
		return err
	}
	if err := os.MkdirAll(filepath.Join(*storage, "repos"), 0755); err != nil {
		return err
	}

	s := &Server{db: db, storage: *storage}
	fmt.Printf("gitocean listening on %s, storage=%s\n", *addr, *storage)
	return http.ListenAndServe(*addr, s)
}

func openMySQLAndCreateDatabaseIfMissing(dsn string) (*sql.DB, error) {
	db, err := sql.Open("mysql", dsn)
	if err != nil {
		return nil, err
	}
	if err := db.Ping(); err == nil {
		return db, nil
	} else {
		_ = db.Close()
		var mysqlErr *mysql.MySQLError
		if !errors.As(err, &mysqlErr) || mysqlErr.Number != 1049 {
			return nil, err
		}
	}

	cfg, err := mysql.ParseDSN(dsn)
	if err != nil {
		return nil, err
	}
	if cfg.DBName == "" {
		return nil, errors.New("DSN does not include a database name")
	}
	databaseName := cfg.DBName
	cfg.DBName = ""

	adminDB, err := sql.Open("mysql", cfg.FormatDSN())
	if err != nil {
		return nil, err
	}
	defer adminDB.Close()
	if err := adminDB.Ping(); err != nil {
		return nil, err
	}
	if _, err := adminDB.Exec("CREATE DATABASE IF NOT EXISTS " + quoteMySQLIdentifier(databaseName) + " CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci"); err != nil {
		return nil, err
	}
	fmt.Printf("created database %q\n", databaseName)

	db, err = sql.Open("mysql", dsn)
	if err != nil {
		return nil, err
	}
	if err := db.Ping(); err != nil {
		_ = db.Close()
		return nil, err
	}
	return db, nil
}

func quoteMySQLIdentifier(name string) string {
	return "`" + strings.ReplaceAll(name, "`", "``") + "`"
}

func migrate(db *sql.DB) error {
	stmts := []string{
		`CREATE TABLE IF NOT EXISTS users (
			id BIGINT AUTO_INCREMENT PRIMARY KEY,
			email VARCHAR(255) NOT NULL UNIQUE,
			username VARCHAR(32) NOT NULL UNIQUE,
			password_hash VARCHAR(255) NOT NULL,
			created_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP
		) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4`,
		`CREATE TABLE IF NOT EXISTS auth_tokens (
			id BIGINT AUTO_INCREMENT PRIMARY KEY,
			user_id BIGINT NOT NULL,
			token_hash CHAR(64) NOT NULL UNIQUE,
			expires_at TIMESTAMP NOT NULL,
			revoked_at TIMESTAMP NULL,
			created_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
			INDEX idx_auth_tokens_user_id (user_id),
			INDEX idx_auth_tokens_expires_at (expires_at),
			CONSTRAINT fk_auth_tokens_user FOREIGN KEY (user_id) REFERENCES users(id) ON DELETE CASCADE
		) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4`,
		`CREATE TABLE IF NOT EXISTS repositories (
			id BIGINT AUTO_INCREMENT PRIMARY KEY,
			owner_user_id BIGINT NOT NULL,
			name VARCHAR(100) NOT NULL,
			visibility ENUM('public','private') NOT NULL,
			forked_from_repository_id BIGINT NULL,
			created_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
			updated_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
			UNIQUE KEY uniq_owner_name (owner_user_id, name),
			INDEX idx_repositories_name (name),
			CONSTRAINT fk_repositories_owner FOREIGN KEY (owner_user_id) REFERENCES users(id) ON DELETE CASCADE,
			CONSTRAINT fk_repositories_fork FOREIGN KEY (forked_from_repository_id) REFERENCES repositories(id) ON DELETE SET NULL
		) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4`,
		`CREATE TABLE IF NOT EXISTS pull_requests (
			id BIGINT AUTO_INCREMENT PRIMARY KEY,
			target_repository_id BIGINT NOT NULL,
			number INT NOT NULL,
			author_user_id BIGINT NOT NULL,
			source_repository_id BIGINT NOT NULL,
			source_branch VARCHAR(200) NOT NULL,
			target_branch VARCHAR(200) NOT NULL,
			title VARCHAR(255) NOT NULL,
			description TEXT NOT NULL,
			status ENUM('open','closed','merged') NOT NULL DEFAULT 'open',
			closed_at TIMESTAMP NULL,
			merged_at TIMESTAMP NULL,
			created_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
			updated_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
			UNIQUE KEY uniq_target_number (target_repository_id, number),
			INDEX idx_pr_target (target_repository_id),
			INDEX idx_pr_source (source_repository_id),
			CONSTRAINT fk_pr_target FOREIGN KEY (target_repository_id) REFERENCES repositories(id) ON DELETE CASCADE,
			CONSTRAINT fk_pr_source FOREIGN KEY (source_repository_id) REFERENCES repositories(id) ON DELETE CASCADE,
			CONSTRAINT fk_pr_author FOREIGN KEY (author_user_id) REFERENCES users(id) ON DELETE CASCADE
		) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4`,
	}
	for _, stmt := range stmts {
		if _, err := db.Exec(stmt); err != nil {
			return err
		}
	}
	return nil
}

// ---------------- HTTP routing ----------------

func (s *Server) ServeHTTP(w http.ResponseWriter, r *http.Request) {
	if strings.HasPrefix(r.URL.Path, "/api/") {
		s.handleAPI(w, r)
		return
	}
	if strings.Contains(r.URL.Path, ".git") {
		s.handleGitHTTP(w, r)
		return
	}
	writeError(w, http.StatusNotFound, "not found")
}

func (s *Server) handleAPI(w http.ResponseWriter, r *http.Request) {
	path := strings.TrimPrefix(r.URL.Path, "/api")
	switch {
	case r.Method == http.MethodPost && path == "/register":
		s.handleRegister(w, r)
	case r.Method == http.MethodPost && path == "/login":
		s.handleLogin(w, r)
	case r.Method == http.MethodPost && path == "/logout":
		s.handleLogout(w, r)
	case r.Method == http.MethodGet && path == "/me":
		s.handleMe(w, r)
	case r.Method == http.MethodPost && path == "/repos":
		s.handleRepoCreate(w, r)
	case r.Method == http.MethodGet && path == "/repos/search":
		s.handleRepoSearch(w, r)
	case strings.HasPrefix(path, "/repos/"):
		s.handleRepoSubroute(w, r, strings.TrimPrefix(path, "/repos/"))
	default:
		writeError(w, http.StatusNotFound, "not found")
	}
}

func (s *Server) handleRepoSubroute(w http.ResponseWriter, r *http.Request, rest string) {
	parts := strings.Split(rest, "/")
	if len(parts) < 2 {
		writeError(w, http.StatusNotFound, "not found")
		return
	}
	owner, repo := parts[0], parts[1]
	if len(parts) == 2 {
		switch r.Method {
		case http.MethodGet:
			s.handleRepoGet(w, r, owner, repo)
		case http.MethodDelete:
			s.handleRepoDelete(w, r, owner, repo)
		default:
			writeError(w, http.StatusMethodNotAllowed, "method not allowed")
		}
		return
	}
	if len(parts) == 3 && parts[2] == "fork" && r.Method == http.MethodPost {
		s.handleRepoFork(w, r, owner, repo)
		return
	}
	if len(parts) >= 3 && parts[2] == "pulls" {
		if len(parts) == 3 {
			switch r.Method {
			case http.MethodGet:
				s.handlePRList(w, r, owner, repo)
			case http.MethodPost:
				s.handlePRCreate(w, r, owner, repo)
			default:
				writeError(w, http.StatusMethodNotAllowed, "method not allowed")
			}
			return
		}
		if len(parts) >= 4 {
			n, err := strconv.Atoi(parts[3])
			if err != nil {
				writeError(w, http.StatusBadRequest, "invalid pull request number")
				return
			}
			if len(parts) == 4 && r.Method == http.MethodGet {
				s.handlePRView(w, r, owner, repo, n)
				return
			}
			if len(parts) == 5 && r.Method == http.MethodPost && parts[4] == "close" {
				s.handlePRClose(w, r, owner, repo, n)
				return
			}
			if len(parts) == 5 && r.Method == http.MethodPost && parts[4] == "merge" {
				s.handlePRMerge(w, r, owner, repo, n)
				return
			}
		}
	}
	writeError(w, http.StatusNotFound, "not found")
}

// ---------------- Auth API ----------------

func (s *Server) handleRegister(w http.ResponseWriter, r *http.Request) {
	var in struct {
		Email    string `json:"email"`
		Username string `json:"username"`
		Password string `json:"password"`
	}
	if !decodeJSON(w, r, &in) {
		return
	}
	in.Email = strings.ToLower(strings.TrimSpace(in.Email))
	in.Username = strings.ToLower(strings.TrimSpace(in.Username))
	if !strings.Contains(in.Email, "@") || len(in.Email) > 255 {
		writeError(w, http.StatusBadRequest, "invalid email")
		return
	}
	if !usernameRE.MatchString(in.Username) || isReservedName(in.Username) {
		writeError(w, http.StatusBadRequest, "invalid or reserved username")
		return
	}
	if len(in.Password) < 8 {
		writeError(w, http.StatusBadRequest, "password must be at least 8 characters")
		return
	}
	hash, err := bcrypt.GenerateFromPassword([]byte(in.Password), bcrypt.DefaultCost)
	if err != nil {
		writeError(w, http.StatusInternalServerError, "password hash failed")
		return
	}
	res, err := s.db.Exec(`INSERT INTO users (email, username, password_hash) VALUES (?, ?, ?)`, in.Email, in.Username, string(hash))
	if err != nil {
		writeError(w, http.StatusConflict, "email or username already exists")
		return
	}
	id, _ := res.LastInsertId()
	writeJSON(w, http.StatusCreated, User{ID: id, Email: in.Email, Username: in.Username})
}

func (s *Server) handleLogin(w http.ResponseWriter, r *http.Request) {
	var in struct {
		Login    string `json:"login"`
		Password string `json:"password"`
	}
	if !decodeJSON(w, r, &in) {
		return
	}
	login := strings.ToLower(strings.TrimSpace(in.Login))
	var user User
	var hash string
	err := s.db.QueryRow(`SELECT id, email, username, password_hash FROM users WHERE email = ? OR username = ?`, login, login).Scan(&user.ID, &user.Email, &user.Username, &hash)
	if err != nil || bcrypt.CompareHashAndPassword([]byte(hash), []byte(in.Password)) != nil {
		writeError(w, http.StatusUnauthorized, "invalid credentials")
		return
	}
	token, expiresAt, err := s.createToken(user.ID)
	if err != nil {
		writeError(w, http.StatusInternalServerError, "token creation failed")
		return
	}
	writeJSON(w, http.StatusOK, map[string]any{"user": user, "token": token, "expires_at": expiresAt})
}

func (s *Server) handleLogout(w http.ResponseWriter, r *http.Request) {
	token := bearerToken(r)
	if token == "" {
		writeError(w, http.StatusUnauthorized, "missing token")
		return
	}
	_, _ = s.db.Exec(`UPDATE auth_tokens SET revoked_at = UTC_TIMESTAMP() WHERE token_hash = ?`, hashToken(token))
	writeJSON(w, http.StatusOK, map[string]string{"status": "ok"})
}

func (s *Server) handleMe(w http.ResponseWriter, r *http.Request) {
	user, ok := s.requireBearerUser(w, r)
	if !ok {
		return
	}
	writeJSON(w, http.StatusOK, user)
}

func (s *Server) createToken(userID int64) (string, time.Time, error) {
	raw := make([]byte, 32)
	if _, err := rand.Read(raw); err != nil {
		return "", time.Time{}, err
	}
	token := "go_" + base64.RawURLEncoding.EncodeToString(raw)
	expiresAt := time.Now().UTC().Add(tokenTTL)
	_, err := s.db.Exec(`INSERT INTO auth_tokens (user_id, token_hash, expires_at) VALUES (?, ?, ?)`, userID, hashToken(token), expiresAt)
	return token, expiresAt, err
}

func hashToken(token string) string {
	sum := sha256.Sum256([]byte(token))
	return hex.EncodeToString(sum[:])
}

func bearerToken(r *http.Request) string {
	h := r.Header.Get("Authorization")
	if strings.HasPrefix(strings.ToLower(h), "bearer ") {
		return strings.TrimSpace(h[7:])
	}
	return ""
}

func (s *Server) requireBearerUser(w http.ResponseWriter, r *http.Request) (User, bool) {
	user, err := s.userFromToken(bearerToken(r), "")
	if err != nil {
		writeError(w, http.StatusUnauthorized, "unauthorized")
		return User{}, false
	}
	return user, true
}

func (s *Server) optionalBearerUser(r *http.Request) (User, bool) {
	user, err := s.userFromToken(bearerToken(r), "")
	return user, err == nil
}

func (s *Server) userFromToken(token, requiredUsername string) (User, error) {
	if token == "" {
		return User{}, errors.New("missing token")
	}
	var user User
	query := `SELECT u.id, u.email, u.username
		FROM auth_tokens t JOIN users u ON u.id = t.user_id
		WHERE t.token_hash = ? AND t.revoked_at IS NULL AND t.expires_at > UTC_TIMESTAMP()`
	args := []any{hashToken(token)}
	if requiredUsername != "" {
		query += ` AND u.username = ?`
		args = append(args, requiredUsername)
	}
	err := s.db.QueryRow(query, args...).Scan(&user.ID, &user.Email, &user.Username)
	if err != nil {
		return User{}, err
	}
	return user, nil
}

func (s *Server) userFromBasic(r *http.Request) (User, bool) {
	username, token, ok := r.BasicAuth()
	if !ok {
		return User{}, false
	}
	user, err := s.userFromToken(token, strings.ToLower(username))
	return user, err == nil
}

// ---------------- Repository API ----------------

func (s *Server) handleRepoCreate(w http.ResponseWriter, r *http.Request) {
	user, ok := s.requireBearerUser(w, r)
	if !ok {
		return
	}
	var in struct {
		Name       string `json:"name"`
		Visibility string `json:"visibility"`
	}
	if !decodeJSON(w, r, &in) {
		return
	}
	name := strings.ToLower(strings.TrimSpace(in.Name))
	visibility := strings.ToLower(strings.TrimSpace(in.Visibility))
	if !repoNameRE.MatchString(name) || isReservedName(name) {
		writeError(w, http.StatusBadRequest, "invalid repository name")
		return
	}
	if visibility != "public" && visibility != "private" {
		writeError(w, http.StatusBadRequest, "visibility must be public or private")
		return
	}
	res, err := s.db.Exec(`INSERT INTO repositories (owner_user_id, name, visibility) VALUES (?, ?, ?)`, user.ID, name, visibility)
	if err != nil {
		writeError(w, http.StatusConflict, "repository already exists")
		return
	}
	repoID, _ := res.LastInsertId()
	path := s.repoPath(user.Username, name)
	if err := os.MkdirAll(filepath.Dir(path), 0755); err != nil {
		_, _ = s.db.Exec(`DELETE FROM repositories WHERE id = ?`, repoID)
		writeError(w, http.StatusInternalServerError, err.Error())
		return
	}
	if err := gitInitBare(path); err != nil {
		_, _ = s.db.Exec(`DELETE FROM repositories WHERE id = ?`, repoID)
		writeError(w, http.StatusInternalServerError, err.Error())
		return
	}
	writeJSON(w, http.StatusCreated, Repository{ID: repoID, OwnerUserID: user.ID, Owner: user.Username, Name: name, Visibility: visibility})
}

func (s *Server) handleRepoSearch(w http.ResponseWriter, r *http.Request) {
	q := strings.TrimSpace(r.URL.Query().Get("q"))
	scope := r.URL.Query().Get("scope")
	if scope == "" {
		scope = "all"
	}
	user, authed := s.optionalBearerUser(r)
	var rows *sql.Rows
	var err error
	like := "%" + q + "%"
	if scope == "mine" {
		if !authed {
			writeError(w, http.StatusUnauthorized, "scope=mine requires auth")
			return
		}
		rows, err = s.db.Query(`SELECT r.id, r.owner_user_id, u.username, r.name, r.visibility, r.forked_from_repository_id, r.created_at, r.updated_at
			FROM repositories r JOIN users u ON u.id = r.owner_user_id
			WHERE r.owner_user_id = ? AND (? = '' OR r.name LIKE ?)
			ORDER BY r.updated_at DESC LIMIT 100`, user.ID, q, like)
	} else if scope == "all" {
		if authed {
			rows, err = s.db.Query(`SELECT r.id, r.owner_user_id, u.username, r.name, r.visibility, r.forked_from_repository_id, r.created_at, r.updated_at
				FROM repositories r JOIN users u ON u.id = r.owner_user_id
				WHERE (r.visibility = 'public' OR r.owner_user_id = ?) AND (? = '' OR r.name LIKE ? OR u.username LIKE ?)
				ORDER BY r.updated_at DESC LIMIT 100`, user.ID, q, like, like)
		} else {
			rows, err = s.db.Query(`SELECT r.id, r.owner_user_id, u.username, r.name, r.visibility, r.forked_from_repository_id, r.created_at, r.updated_at
				FROM repositories r JOIN users u ON u.id = r.owner_user_id
				WHERE r.visibility = 'public' AND (? = '' OR r.name LIKE ? OR u.username LIKE ?)
				ORDER BY r.updated_at DESC LIMIT 100`, q, like, like)
		}
	} else {
		writeError(w, http.StatusBadRequest, "scope must be all or mine")
		return
	}
	if err != nil {
		writeError(w, http.StatusInternalServerError, err.Error())
		return
	}
	defer rows.Close()
	repos, err := scanRepos(rows)
	if err != nil {
		writeError(w, http.StatusInternalServerError, err.Error())
		return
	}
	writeJSON(w, http.StatusOK, repos)
}

func (s *Server) handleRepoGet(w http.ResponseWriter, r *http.Request, owner, name string) {
	repo, err := s.loadRepo(owner, name)
	if err != nil {
		writeError(w, http.StatusNotFound, "repository not found")
		return
	}
	user, authed := s.optionalBearerUser(r)
	if repo.Visibility == "private" && (!authed || user.ID != repo.OwnerUserID) {
		writeError(w, http.StatusNotFound, "repository not found")
		return
	}
	writeJSON(w, http.StatusOK, repo)
}

func (s *Server) handleRepoDelete(w http.ResponseWriter, r *http.Request, owner, name string) {
	user, ok := s.requireBearerUser(w, r)
	if !ok {
		return
	}
	repo, err := s.loadRepo(owner, name)
	if err != nil {
		writeError(w, http.StatusNotFound, "repository not found")
		return
	}
	if repo.OwnerUserID != user.ID {
		writeError(w, http.StatusForbidden, "only the owner can delete this repository")
		return
	}
	force := r.URL.Query().Get("force") == "true" || r.URL.Query().Get("force") == "1"
	var openCount int
	_ = s.db.QueryRow(`SELECT COUNT(*) FROM pull_requests WHERE status = 'open' AND (target_repository_id = ? OR source_repository_id = ?)`, repo.ID, repo.ID).Scan(&openCount)
	if openCount > 0 && !force {
		writeError(w, http.StatusConflict, "repository has open pull requests; use force=true")
		return
	}
	if force {
		_, _ = s.db.Exec(`DELETE FROM pull_requests WHERE target_repository_id = ? OR source_repository_id = ?`, repo.ID, repo.ID)
	}
	_, err = s.db.Exec(`DELETE FROM repositories WHERE id = ?`, repo.ID)
	if err != nil {
		writeError(w, http.StatusInternalServerError, err.Error())
		return
	}
	_ = os.RemoveAll(s.repoPath(owner, name))
	writeJSON(w, http.StatusOK, map[string]string{"status": "deleted"})
}

func (s *Server) handleRepoFork(w http.ResponseWriter, r *http.Request, owner, name string) {
	user, ok := s.requireBearerUser(w, r)
	if !ok {
		return
	}
	src, err := s.loadRepo(owner, name)
	if err != nil {
		writeError(w, http.StatusNotFound, "repository not found")
		return
	}
	if src.Visibility == "private" && src.OwnerUserID != user.ID {
		writeError(w, http.StatusForbidden, "cannot fork this private repository")
		return
	}
	var in struct {
		Name string `json:"name"`
	}
	_ = json.NewDecoder(r.Body).Decode(&in)
	newName := strings.ToLower(strings.TrimSpace(in.Name))
	if newName == "" {
		newName = src.Name
	}
	if !repoNameRE.MatchString(newName) || isReservedName(newName) {
		writeError(w, http.StatusBadRequest, "invalid repository name")
		return
	}
	res, err := s.db.Exec(`INSERT INTO repositories (owner_user_id, name, visibility, forked_from_repository_id) VALUES (?, ?, ?, ?)`, user.ID, newName, src.Visibility, src.ID)
	if err != nil {
		writeError(w, http.StatusConflict, "repository already exists")
		return
	}
	newID, _ := res.LastInsertId()
	dstPath := s.repoPath(user.Username, newName)
	if err := os.MkdirAll(filepath.Dir(dstPath), 0755); err != nil {
		_, _ = s.db.Exec(`DELETE FROM repositories WHERE id = ?`, newID)
		writeError(w, http.StatusInternalServerError, err.Error())
		return
	}
	cmd := exec.Command("git", "clone", "--bare", s.repoPath(src.Owner, src.Name), dstPath)
	if out, err := cmd.CombinedOutput(); err != nil {
		_, _ = s.db.Exec(`DELETE FROM repositories WHERE id = ?`, newID)
		_ = os.RemoveAll(dstPath)
		writeError(w, http.StatusInternalServerError, string(out))
		return
	}
	writeJSON(w, http.StatusCreated, Repository{ID: newID, OwnerUserID: user.ID, Owner: user.Username, Name: newName, Visibility: src.Visibility, ForkedFromID: &src.ID})
}

func (s *Server) loadRepo(owner, name string) (Repository, error) {
	var repo Repository
	var fork sql.NullInt64
	err := s.db.QueryRow(`SELECT r.id, r.owner_user_id, u.username, r.name, r.visibility, r.forked_from_repository_id, r.created_at, r.updated_at
		FROM repositories r JOIN users u ON u.id = r.owner_user_id
		WHERE u.username = ? AND r.name = ?`, strings.ToLower(owner), strings.ToLower(name)).Scan(&repo.ID, &repo.OwnerUserID, &repo.Owner, &repo.Name, &repo.Visibility, &fork, &repo.CreatedAt, &repo.UpdatedAt)
	if fork.Valid {
		repo.ForkedFromID = &fork.Int64
	}
	return repo, err
}

func scanRepos(rows *sql.Rows) ([]Repository, error) {
	var repos []Repository
	for rows.Next() {
		var repo Repository
		var fork sql.NullInt64
		if err := rows.Scan(&repo.ID, &repo.OwnerUserID, &repo.Owner, &repo.Name, &repo.Visibility, &fork, &repo.CreatedAt, &repo.UpdatedAt); err != nil {
			return nil, err
		}
		if fork.Valid {
			repo.ForkedFromID = &fork.Int64
		}
		repos = append(repos, repo)
	}
	return repos, rows.Err()
}

// ---------------- Pull request API ----------------

func (s *Server) handlePRCreate(w http.ResponseWriter, r *http.Request, targetOwner, targetName string) {
	user, ok := s.requireBearerUser(w, r)
	if !ok {
		return
	}
	target, err := s.loadRepo(targetOwner, targetName)
	if err != nil {
		writeError(w, http.StatusNotFound, "target repository not found")
		return
	}
	var in struct {
		SourceOwner  string `json:"source_owner"`
		SourceRepo   string `json:"source_repo"`
		SourceBranch string `json:"source_branch"`
		TargetBranch string `json:"target_branch"`
		Title        string `json:"title"`
		Description  string `json:"description"`
	}
	if !decodeJSON(w, r, &in) {
		return
	}
	in.SourceOwner = strings.ToLower(strings.TrimSpace(in.SourceOwner))
	in.SourceRepo = strings.ToLower(strings.TrimSpace(in.SourceRepo))
	in.SourceBranch = strings.TrimSpace(in.SourceBranch)
	in.TargetBranch = strings.TrimSpace(in.TargetBranch)
	in.Title = strings.TrimSpace(in.Title)
	if in.SourceOwner == "" {
		in.SourceOwner = target.Owner
	}
	if in.SourceRepo == "" {
		in.SourceRepo = target.Name
	}
	if in.Title == "" || !branchRE.MatchString(in.SourceBranch) || !branchRE.MatchString(in.TargetBranch) {
		writeError(w, http.StatusBadRequest, "title and valid source/target branches are required")
		return
	}
	source, err := s.loadRepo(in.SourceOwner, in.SourceRepo)
	if err != nil {
		writeError(w, http.StatusNotFound, "source repository not found")
		return
	}
	if source.ID == target.ID {
		if target.OwnerUserID != user.ID {
			writeError(w, http.StatusForbidden, "same-repository PRs require repository ownership")
			return
		}
	} else {
		if source.OwnerUserID != user.ID {
			writeError(w, http.StatusForbidden, "source repository must be owned by you")
			return
		}
		if target.Visibility != "public" && target.OwnerUserID != user.ID {
			writeError(w, http.StatusForbidden, "target repository is private")
			return
		}
	}
	if !gitBranchExists(s.repoPath(source.Owner, source.Name), in.SourceBranch) {
		writeError(w, http.StatusBadRequest, "source branch does not exist")
		return
	}
	if !gitBranchExists(s.repoPath(target.Owner, target.Name), in.TargetBranch) {
		writeError(w, http.StatusBadRequest, "target branch does not exist")
		return
	}
	var number int
	_ = s.db.QueryRow(`SELECT COALESCE(MAX(number), 0) + 1 FROM pull_requests WHERE target_repository_id = ?`, target.ID).Scan(&number)
	res, err := s.db.Exec(`INSERT INTO pull_requests (target_repository_id, number, author_user_id, source_repository_id, source_branch, target_branch, title, description)
		VALUES (?, ?, ?, ?, ?, ?, ?, ?)`, target.ID, number, user.ID, source.ID, in.SourceBranch, in.TargetBranch, in.Title, in.Description)
	if err != nil {
		writeError(w, http.StatusInternalServerError, err.Error())
		return
	}
	id, _ := res.LastInsertId()
	pr, _ := s.loadPR(target.ID, number)
	pr.ID = id
	writeJSON(w, http.StatusCreated, pr)
}

func (s *Server) handlePRList(w http.ResponseWriter, r *http.Request, owner, name string) {
	repo, err := s.loadRepo(owner, name)
	if err != nil {
		writeError(w, http.StatusNotFound, "repository not found")
		return
	}
	user, authed := s.optionalBearerUser(r)
	if repo.Visibility == "private" && (!authed || user.ID != repo.OwnerUserID) {
		writeError(w, http.StatusNotFound, "repository not found")
		return
	}
	rows, err := s.db.Query(prSelectSQL()+` WHERE pr.target_repository_id = ? ORDER BY pr.number DESC`, repo.ID)
	if err != nil {
		writeError(w, http.StatusInternalServerError, err.Error())
		return
	}
	defer rows.Close()
	prs, err := scanPRs(rows)
	if err != nil {
		writeError(w, http.StatusInternalServerError, err.Error())
		return
	}
	writeJSON(w, http.StatusOK, prs)
}

func (s *Server) handlePRView(w http.ResponseWriter, r *http.Request, owner, name string, number int) {
	repo, err := s.loadRepo(owner, name)
	if err != nil {
		writeError(w, http.StatusNotFound, "repository not found")
		return
	}
	user, authed := s.optionalBearerUser(r)
	if repo.Visibility == "private" && (!authed || user.ID != repo.OwnerUserID) {
		writeError(w, http.StatusNotFound, "repository not found")
		return
	}
	pr, err := s.loadPR(repo.ID, number)
	if err != nil {
		writeError(w, http.StatusNotFound, "pull request not found")
		return
	}
	writeJSON(w, http.StatusOK, pr)
}

func (s *Server) handlePRClose(w http.ResponseWriter, r *http.Request, owner, name string, number int) {
	user, ok := s.requireBearerUser(w, r)
	if !ok {
		return
	}
	repo, err := s.loadRepo(owner, name)
	if err != nil {
		writeError(w, http.StatusNotFound, "repository not found")
		return
	}
	if repo.OwnerUserID != user.ID {
		writeError(w, http.StatusForbidden, "only target owner can close pull requests")
		return
	}
	res, err := s.db.Exec(`UPDATE pull_requests SET status = 'closed', closed_at = UTC_TIMESTAMP() WHERE target_repository_id = ? AND number = ? AND status = 'open'`, repo.ID, number)
	if err != nil {
		writeError(w, http.StatusInternalServerError, err.Error())
		return
	}
	affected, _ := res.RowsAffected()
	if affected == 0 {
		writeError(w, http.StatusConflict, "pull request is not open")
		return
	}
	pr, _ := s.loadPR(repo.ID, number)
	writeJSON(w, http.StatusOK, pr)
}

func (s *Server) handlePRMerge(w http.ResponseWriter, r *http.Request, owner, name string, number int) {
	user, ok := s.requireBearerUser(w, r)
	if !ok {
		return
	}
	target, err := s.loadRepo(owner, name)
	if err != nil {
		writeError(w, http.StatusNotFound, "repository not found")
		return
	}
	if target.OwnerUserID != user.ID {
		writeError(w, http.StatusForbidden, "only target owner can merge pull requests")
		return
	}
	pr, err := s.loadPR(target.ID, number)
	if err != nil || pr.Status != "open" {
		writeError(w, http.StatusConflict, "pull request is not open")
		return
	}
	if err := s.mergePR(pr); err != nil {
		writeError(w, http.StatusConflict, err.Error())
		return
	}
	_, err = s.db.Exec(`UPDATE pull_requests SET status = 'merged', merged_at = UTC_TIMESTAMP() WHERE target_repository_id = ? AND number = ?`, target.ID, number)
	if err != nil {
		writeError(w, http.StatusInternalServerError, err.Error())
		return
	}
	pr, _ = s.loadPR(target.ID, number)
	writeJSON(w, http.StatusOK, pr)
}

func prSelectSQL() string {
	return `SELECT pr.id, pr.number, pr.target_repository_id, pr.source_repository_id, pr.author_user_id,
		au.username, su.username, sr.name, pr.source_branch, tu.username, tr.name, pr.target_branch,
		pr.title, pr.description, pr.status, pr.created_at, pr.updated_at, pr.closed_at, pr.merged_at
		FROM pull_requests pr
		JOIN users au ON au.id = pr.author_user_id
		JOIN repositories sr ON sr.id = pr.source_repository_id
		JOIN users su ON su.id = sr.owner_user_id
		JOIN repositories tr ON tr.id = pr.target_repository_id
		JOIN users tu ON tu.id = tr.owner_user_id`
}

func (s *Server) loadPR(targetRepoID int64, number int) (PullRequest, error) {
	row := s.db.QueryRow(prSelectSQL()+` WHERE pr.target_repository_id = ? AND pr.number = ?`, targetRepoID, number)
	prs, err := scanOnePR(row)
	return prs, err
}

type scanner interface{ Scan(dest ...any) error }

func scanOnePR(row scanner) (PullRequest, error) {
	var pr PullRequest
	var closedAt, mergedAt sql.NullTime
	err := row.Scan(&pr.ID, &pr.Number, &pr.TargetRepositoryID, &pr.SourceRepositoryID, &pr.AuthorUserID,
		&pr.Author, &pr.SourceOwner, &pr.SourceRepo, &pr.SourceBranch, &pr.TargetOwner, &pr.TargetRepo, &pr.TargetBranch,
		&pr.Title, &pr.Description, &pr.Status, &pr.CreatedAt, &pr.UpdatedAt, &closedAt, &mergedAt)
	if closedAt.Valid {
		pr.ClosedAt = &closedAt.Time
	}
	if mergedAt.Valid {
		pr.MergedAt = &mergedAt.Time
	}
	return pr, err
}

func scanPRs(rows *sql.Rows) ([]PullRequest, error) {
	var prs []PullRequest
	for rows.Next() {
		pr, err := scanOnePR(rows)
		if err != nil {
			return nil, err
		}
		prs = append(prs, pr)
	}
	return prs, rows.Err()
}

func (s *Server) mergePR(pr PullRequest) error {
	targetPath := s.repoPath(pr.TargetOwner, pr.TargetRepo)
	sourcePath := s.repoPath(pr.SourceOwner, pr.SourceRepo)
	tmp, err := os.MkdirTemp("", "gitocean-merge-*")
	if err != nil {
		return err
	}
	defer os.RemoveAll(tmp)
	work := filepath.Join(tmp, "work")
	if err := runGit("", "clone", targetPath, work); err != nil {
		return err
	}
	if err := runGit(work, "config", "user.name", "gitocean"); err != nil {
		return err
	}
	if err := runGit(work, "config", "user.email", "gitocean@localhost"); err != nil {
		return err
	}
	if err := runGit(work, "checkout", pr.TargetBranch); err != nil {
		return err
	}
	if err := runGit(work, "remote", "add", "source", sourcePath); err != nil {
		return err
	}
	if err := runGit(work, "fetch", "source", pr.SourceBranch); err != nil {
		return err
	}
	msg := fmt.Sprintf("Merge pull request #%d from %s/%s:%s", pr.Number, pr.SourceOwner, pr.SourceRepo, pr.SourceBranch)
	if err := runGit(work, "merge", "--no-ff", "FETCH_HEAD", "-m", msg); err != nil {
		return fmt.Errorf("merge failed, likely due to conflicts: %w", err)
	}
	if err := runGit(work, "push", "origin", "HEAD:"+pr.TargetBranch); err != nil {
		return err
	}
	return nil
}

// ---------------- Git HTTP ----------------

func (s *Server) handleGitHTTP(w http.ResponseWriter, r *http.Request) {
	owner, repoName, _, ok := parseGitPath(r.URL.Path)
	if !ok {
		writeError(w, http.StatusNotFound, "invalid git path")
		return
	}
	repo, err := s.loadRepo(owner, repoName)
	if err != nil {
		writeError(w, http.StatusNotFound, "repository not found")
		return
	}
	service := gitService(r)
	user, authed := s.userFromBasic(r)
	if service == "git-receive-pack" {
		if !authed {
			w.Header().Set("WWW-Authenticate", `Basic realm="gitocean"`)
			writeError(w, http.StatusUnauthorized, "authentication required")
			return
		}
		if user.ID != repo.OwnerUserID {
			writeError(w, http.StatusForbidden, "only owner can push")
			return
		}
	} else {
		if repo.Visibility == "private" {
			if !authed {
				w.Header().Set("WWW-Authenticate", `Basic realm="gitocean"`)
				writeError(w, http.StatusUnauthorized, "authentication required")
				return
			}
			if user.ID != repo.OwnerUserID {
				writeError(w, http.StatusForbidden, "not allowed")
				return
			}
		}
	}
	s.runGitHTTPBackend(w, r, authed, user.Username)
}

func parseGitPath(path string) (owner, repo, rest string, ok bool) {
	path = strings.TrimPrefix(path, "/")
	idx := strings.Index(path, ".git")
	if idx < 0 {
		return "", "", "", false
	}
	repoPart := path[:idx]
	rest = path[idx+len(".git"):]
	parts := strings.Split(repoPart, "/")
	if len(parts) != 2 {
		return "", "", "", false
	}
	return parts[0], parts[1], rest, true
}

func gitService(r *http.Request) string {
	if svc := r.URL.Query().Get("service"); svc != "" {
		return svc
	}
	if strings.HasSuffix(r.URL.Path, "/git-receive-pack") {
		return "git-receive-pack"
	}
	return "git-upload-pack"
}

func (s *Server) runGitHTTPBackend(w http.ResponseWriter, r *http.Request, authed bool, username string) {
	root, _ := filepath.Abs(filepath.Join(s.storage, "repos"))
	env := append(os.Environ(),
		"GIT_PROJECT_ROOT="+root,
		"GIT_HTTP_EXPORT_ALL=1",
		"PATH_INFO="+r.URL.Path,
		"REQUEST_METHOD="+r.Method,
		"QUERY_STRING="+r.URL.RawQuery,
		"REMOTE_ADDR="+r.RemoteAddr,
	)
	if ct := r.Header.Get("Content-Type"); ct != "" {
		env = append(env, "CONTENT_TYPE="+ct)
	}
	if r.ContentLength >= 0 {
		env = append(env, fmt.Sprintf("CONTENT_LENGTH=%d", r.ContentLength))
	}
	if authed {
		env = append(env, "REMOTE_USER="+username, "AUTH_TYPE=Basic")
	}
	cmd := exec.Command("git", "http-backend")
	cmd.Env = env
	cmd.Stdin = r.Body
	var out, errBuf bytes.Buffer
	cmd.Stdout = &out
	cmd.Stderr = &errBuf
	if err := cmd.Run(); err != nil {
		writeError(w, http.StatusInternalServerError, strings.TrimSpace(errBuf.String()))
		return
	}
	writeCGIResponse(w, out.Bytes())
}

func writeCGIResponse(w http.ResponseWriter, data []byte) {
	sep := []byte("\r\n\r\n")
	idx := bytes.Index(data, sep)
	if idx < 0 {
		sep = []byte("\n\n")
		idx = bytes.Index(data, sep)
	}
	if idx < 0 {
		_, _ = w.Write(data)
		return
	}
	headers := string(data[:idx])
	body := data[idx+len(sep):]
	status := http.StatusOK
	for _, line := range strings.Split(headers, "\n") {
		line = strings.TrimRight(line, "\r")
		if line == "" {
			continue
		}
		k, v, ok := strings.Cut(line, ":")
		if !ok {
			continue
		}
		k = strings.TrimSpace(k)
		v = strings.TrimSpace(v)
		if strings.EqualFold(k, "Status") {
			fields := strings.Fields(v)
			if len(fields) > 0 {
				if n, err := strconv.Atoi(fields[0]); err == nil {
					status = n
				}
			}
			continue
		}
		w.Header().Add(k, v)
	}
	w.WriteHeader(status)
	_, _ = w.Write(body)
}

// ---------------- CLI ----------------

func cliRegister(args []string) error {
	fs := flag.NewFlagSet("register", flag.ExitOnError)
	server := fs.String("server", envServer(), "server URL")
	if err := fs.Parse(args); err != nil {
		return err
	}
	email := prompt("Email: ")
	username := prompt("Username: ")
	password := prompt("Password: ")
	var out User
	if err := apiRequest(context.Background(), *server, http.MethodPost, "/api/register", "", map[string]string{"email": email, "username": username, "password": password}, &out); err != nil {
		return err
	}
	printJSON(out)
	return nil
}

func cliLogin(args []string) error {
	fs := flag.NewFlagSet("login", flag.ExitOnError)
	server := fs.String("server", envServer(), "server URL")
	if err := fs.Parse(args); err != nil {
		return err
	}
	login := prompt("Email or username: ")
	password := prompt("Password: ")
	var out struct {
		User      User      `json:"user"`
		Token     string    `json:"token"`
		ExpiresAt time.Time `json:"expires_at"`
	}
	if err := apiRequest(context.Background(), *server, http.MethodPost, "/api/login", "", map[string]string{"login": login, "password": password}, &out); err != nil {
		return err
	}
	cfg := Config{Server: strings.TrimRight(*server, "/"), Username: out.User.Username, Token: out.Token, ExpiresAt: out.ExpiresAt}
	if err := saveConfig(cfg); err != nil {
		return err
	}
	approveGitCredential(cfg)
	fmt.Printf("logged in as %s; token expires %s\n", cfg.Username, cfg.ExpiresAt.Format(time.RFC3339))
	return nil
}

func cliLogout(args []string) error {
	cfg, err := loadConfig()
	if err != nil {
		return err
	}
	_ = apiRequest(context.Background(), cfg.Server, http.MethodPost, "/api/logout", cfg.Token, nil, nil)
	_ = os.Remove(configPath())
	fmt.Println("logged out")
	return nil
}

func cliWhoami(args []string) error {
	cfg, err := loadConfig()
	if err != nil {
		return err
	}
	var user User
	if err := apiRequest(context.Background(), cfg.Server, http.MethodGet, "/api/me", cfg.Token, nil, &user); err != nil {
		return err
	}
	printJSON(user)
	return nil
}

func cliClone(args []string) error {
	if len(args) != 1 {
		return errors.New("usage: gitocean clone OWNER/REPO")
	}
	server := envServer()
	if cfg, err := loadConfig(); err == nil && cfg.Server != "" {
		server = cfg.Server
	}
	owner, repo, err := splitOwnerRepo(args[0])
	if err != nil {
		return err
	}
	remote := fmt.Sprintf("%s/%s/%s.git", strings.TrimRight(server, "/"), owner, repo)
	cmd := exec.Command("git", "clone", remote)
	cmd.Stdout = os.Stdout
	cmd.Stderr = os.Stderr
	cmd.Stdin = os.Stdin
	return cmd.Run()
}

func cliRepo(args []string) error {
	if len(args) < 1 {
		return errors.New("usage: gitocean repo <create|delete|search|fork>")
	}
	switch args[0] {
	case "create":
		return cliRepoCreate(args[1:])
	case "delete":
		return cliRepoDelete(args[1:])
	case "search":
		return cliRepoSearch(args[1:])
	case "fork":
		return cliRepoFork(args[1:])
	default:
		return fmt.Errorf("unknown repo command %q", args[0])
	}
}

func cliRepoCreate(args []string) error {
	var name string
	pub, priv := false, false
	for _, arg := range args {
		switch arg {
		case "--public", "-public":
			pub = true
		case "--private", "-private":
			priv = true
		default:
			if strings.HasPrefix(arg, "-") {
				return fmt.Errorf("unknown flag %s", arg)
			}
			if name != "" {
				return errors.New("usage: gitocean repo create NAME (--public|--private)")
			}
			name = arg
		}
	}
	if name == "" || pub == priv {
		return errors.New("usage: gitocean repo create NAME (--public|--private)")
	}
	visibility := "private"
	if pub {
		visibility = "public"
	}
	cfg, err := loadConfig()
	if err != nil {
		return err
	}
	var out Repository
	if err := apiRequest(context.Background(), cfg.Server, http.MethodPost, "/api/repos", cfg.Token, map[string]string{"name": name, "visibility": visibility}, &out); err != nil {
		return err
	}
	printJSON(out)
	fmt.Printf("remote: %s/%s/%s.git\n", strings.TrimRight(cfg.Server, "/"), out.Owner, out.Name)
	return nil
}

func cliRepoDelete(args []string) error {
	var repoRef string
	force := false
	for _, arg := range args {
		switch arg {
		case "--force", "-force":
			force = true
		default:
			if strings.HasPrefix(arg, "-") {
				return fmt.Errorf("unknown flag %s", arg)
			}
			if repoRef != "" {
				return errors.New("usage: gitocean repo delete OWNER/REPO [--force]")
			}
			repoRef = arg
		}
	}
	if repoRef == "" {
		return errors.New("usage: gitocean repo delete OWNER/REPO [--force]")
	}
	owner, repo, err := splitOwnerRepo(repoRef)
	if err != nil {
		return err
	}
	cfg, err := loadConfig()
	if err != nil {
		return err
	}
	path := fmt.Sprintf("/api/repos/%s/%s?force=%v", owner, repo, force)
	var out any
	if err := apiRequest(context.Background(), cfg.Server, http.MethodDelete, path, cfg.Token, nil, &out); err != nil {
		return err
	}
	printJSON(out)
	return nil
}

func cliRepoSearch(args []string) error {
	var query string
	scope := "all"
	for _, arg := range args {
		switch arg {
		case "--mine", "-mine":
			scope = "mine"
		case "--all", "-all":
			scope = "all"
		default:
			if strings.HasPrefix(arg, "-") {
				return fmt.Errorf("unknown flag %s", arg)
			}
			if query != "" {
				return errors.New("usage: gitocean repo search QUERY [--all|--mine]")
			}
			query = arg
		}
	}
	if query == "" {
		return errors.New("usage: gitocean repo search QUERY [--all|--mine]")
	}
	server := envServer()
	token := ""
	if cfg, err := loadConfig(); err == nil {
		server, token = cfg.Server, cfg.Token
	}
	path := "/api/repos/search?q=" + url.QueryEscape(query) + "&scope=" + scope
	var out []Repository
	if err := apiRequest(context.Background(), server, http.MethodGet, path, token, nil, &out); err != nil {
		return err
	}
	printJSON(out)
	return nil
}

func cliRepoFork(args []string) error {
	var repoRef string
	newName := ""
	for i := 0; i < len(args); i++ {
		arg := args[i]
		switch {
		case arg == "--name" || arg == "-name":
			if i+1 >= len(args) {
				return errors.New("--name requires a value")
			}
			i++
			newName = args[i]
		case strings.HasPrefix(arg, "--name="):
			newName = strings.TrimPrefix(arg, "--name=")
		case strings.HasPrefix(arg, "-name="):
			newName = strings.TrimPrefix(arg, "-name=")
		default:
			if strings.HasPrefix(arg, "-") {
				return fmt.Errorf("unknown flag %s", arg)
			}
			if repoRef != "" {
				return errors.New("usage: gitocean repo fork OWNER/REPO [--name NEW_NAME]")
			}
			repoRef = arg
		}
	}
	if repoRef == "" {
		return errors.New("usage: gitocean repo fork OWNER/REPO [--name NEW_NAME]")
	}
	owner, repo, err := splitOwnerRepo(repoRef)
	if err != nil {
		return err
	}
	cfg, err := loadConfig()
	if err != nil {
		return err
	}
	var out Repository
	if err := apiRequest(context.Background(), cfg.Server, http.MethodPost, fmt.Sprintf("/api/repos/%s/%s/fork", owner, repo), cfg.Token, map[string]string{"name": newName}, &out); err != nil {
		return err
	}
	printJSON(out)
	return nil
}

func cliPR(args []string) error {
	if len(args) < 1 {
		return errors.New("usage: gitocean pr <create|list|view|close|merge>")
	}
	switch args[0] {
	case "create":
		return cliPRCreate(args[1:])
	case "list":
		return cliPRList(args[1:])
	case "view":
		return cliPRView(args[1:])
	case "close":
		return cliPRAction(args[1:], "close")
	case "merge":
		return cliPRAction(args[1:], "merge")
	default:
		return fmt.Errorf("unknown pr command %q", args[0])
	}
}

func cliPRCreate(args []string) error {
	fs := flag.NewFlagSet("pr create", flag.ExitOnError)
	repoFlag := fs.String("repo", "", "target repo for same-repository PR")
	from := fs.String("from", "", "source branch or OWNER/REPO:BRANCH")
	to := fs.String("to", "", "target branch or OWNER/REPO:BRANCH")
	title := fs.String("title", "", "title")
	desc := fs.String("description", "", "description")
	if err := fs.Parse(args); err != nil {
		return err
	}
	if *from == "" || *to == "" || *title == "" {
		return errors.New("usage: gitocean pr create --from SRC --to DST --title TITLE [--description DESC]")
	}
	var targetOwner, targetRepo, targetBranch, sourceOwner, sourceRepo, sourceBranch string
	if *repoFlag != "" {
		var err error
		targetOwner, targetRepo, err = splitOwnerRepo(*repoFlag)
		if err != nil {
			return err
		}
		sourceOwner, sourceRepo = targetOwner, targetRepo
		sourceBranch, targetBranch = *from, *to
	} else {
		var err error
		sourceOwner, sourceRepo, sourceBranch, err = splitRepoBranch(*from)
		if err != nil {
			return err
		}
		targetOwner, targetRepo, targetBranch, err = splitRepoBranch(*to)
		if err != nil {
			return err
		}
	}
	cfg, err := loadConfig()
	if err != nil {
		return err
	}
	body := map[string]string{"source_owner": sourceOwner, "source_repo": sourceRepo, "source_branch": sourceBranch, "target_branch": targetBranch, "title": *title, "description": *desc}
	var out PullRequest
	if err := apiRequest(context.Background(), cfg.Server, http.MethodPost, fmt.Sprintf("/api/repos/%s/%s/pulls", targetOwner, targetRepo), cfg.Token, body, &out); err != nil {
		return err
	}
	printJSON(out)
	return nil
}

func cliPRList(args []string) error {
	if len(args) != 1 {
		return errors.New("usage: gitocean pr list OWNER/REPO")
	}
	owner, repo, err := splitOwnerRepo(args[0])
	if err != nil {
		return err
	}
	server, token := envServer(), ""
	if cfg, err := loadConfig(); err == nil {
		server, token = cfg.Server, cfg.Token
	}
	var out []PullRequest
	if err := apiRequest(context.Background(), server, http.MethodGet, fmt.Sprintf("/api/repos/%s/%s/pulls", owner, repo), token, nil, &out); err != nil {
		return err
	}
	printJSON(out)
	return nil
}

func cliPRView(args []string) error {
	if len(args) != 2 {
		return errors.New("usage: gitocean pr view OWNER/REPO NUMBER")
	}
	owner, repo, err := splitOwnerRepo(args[0])
	if err != nil {
		return err
	}
	server, token := envServer(), ""
	if cfg, err := loadConfig(); err == nil {
		server, token = cfg.Server, cfg.Token
	}
	var out PullRequest
	if err := apiRequest(context.Background(), server, http.MethodGet, fmt.Sprintf("/api/repos/%s/%s/pulls/%s", owner, repo, args[1]), token, nil, &out); err != nil {
		return err
	}
	printJSON(out)
	return nil
}

func cliPRAction(args []string, action string) error {
	if len(args) != 2 {
		return fmt.Errorf("usage: gitocean pr %s OWNER/REPO NUMBER", action)
	}
	owner, repo, err := splitOwnerRepo(args[0])
	if err != nil {
		return err
	}
	cfg, err := loadConfig()
	if err != nil {
		return err
	}
	var out PullRequest
	if err := apiRequest(context.Background(), cfg.Server, http.MethodPost, fmt.Sprintf("/api/repos/%s/%s/pulls/%s/%s", owner, repo, args[1], action), cfg.Token, nil, &out); err != nil {
		return err
	}
	printJSON(out)
	return nil
}

// ---------------- CLI helpers ----------------

func apiRequest(ctx context.Context, server, method, path, token string, body any, out any) error {
	server = strings.TrimRight(server, "/")
	var rdr io.Reader
	if body != nil {
		b, err := json.Marshal(body)
		if err != nil {
			return err
		}
		rdr = bytes.NewReader(b)
	}
	req, err := http.NewRequestWithContext(ctx, method, server+path, rdr)
	if err != nil {
		return err
	}
	if body != nil {
		req.Header.Set("Content-Type", "application/json")
	}
	if token != "" {
		req.Header.Set("Authorization", "Bearer "+token)
	}
	resp, err := http.DefaultClient.Do(req)
	if err != nil {
		return err
	}
	defer resp.Body.Close()
	b, _ := io.ReadAll(resp.Body)
	if resp.StatusCode >= 300 {
		var e struct {
			Error string `json:"error"`
		}
		if json.Unmarshal(b, &e) == nil && e.Error != "" {
			return fmt.Errorf("%s", e.Error)
		}
		return fmt.Errorf("HTTP %d: %s", resp.StatusCode, strings.TrimSpace(string(b)))
	}
	if out != nil && len(b) > 0 {
		if err := json.Unmarshal(b, out); err != nil {
			return err
		}
	}
	return nil
}

func envServer() string {
	if v := os.Getenv("GITOOCEAN_SERVER"); v != "" {
		return strings.TrimRight(v, "/")
	}
	return defaultServerURL
}

func configPath() string {
	if v := os.Getenv("GITOOCEAN_CONFIG"); v != "" {
		return v
	}
	dir, err := os.UserConfigDir()
	if err != nil {
		dir = "."
	}
	return filepath.Join(dir, "gitocean", "config.json")
}

func loadConfig() (Config, error) {
	b, err := os.ReadFile(configPath())
	if err != nil {
		return Config{}, errors.New("not logged in; run gitocean login")
	}
	var cfg Config
	if err := json.Unmarshal(b, &cfg); err != nil {
		return Config{}, err
	}
	if cfg.Server == "" || cfg.Token == "" {
		return Config{}, errors.New("invalid config; run gitocean login")
	}
	return cfg, nil
}

func saveConfig(cfg Config) error {
	path := configPath()
	if err := os.MkdirAll(filepath.Dir(path), 0700); err != nil {
		return err
	}
	b, _ := json.MarshalIndent(cfg, "", "  ")
	return os.WriteFile(path, b, 0600)
}

func approveGitCredential(cfg Config) {
	u, err := url.Parse(cfg.Server)
	if err != nil || u.Host == "" || u.Scheme == "" {
		return
	}
	cmd := exec.Command("git", "credential", "approve")
	cmd.Stdin = strings.NewReader(fmt.Sprintf("protocol=%s\nhost=%s\nusername=%s\npassword=%s\n\n", u.Scheme, u.Host, cfg.Username, cfg.Token))
	_ = cmd.Run()
}

func prompt(label string) string {
	fmt.Print(label)
	var s string
	fmt.Scanln(&s)
	return strings.TrimSpace(s)
}

func printJSON(v any) {
	b, _ := json.MarshalIndent(v, "", "  ")
	fmt.Println(string(b))
}

func splitOwnerRepo(s string) (string, string, error) {
	parts := strings.Split(s, "/")
	if len(parts) != 2 || parts[0] == "" || parts[1] == "" {
		return "", "", fmt.Errorf("expected OWNER/REPO, got %q", s)
	}
	return strings.ToLower(parts[0]), strings.ToLower(parts[1]), nil
}

func splitRepoBranch(s string) (owner, repo, branch string, err error) {
	left, branch, ok := strings.Cut(s, ":")
	if !ok || branch == "" {
		return "", "", "", fmt.Errorf("expected OWNER/REPO:BRANCH, got %q", s)
	}
	owner, repo, err = splitOwnerRepo(left)
	return owner, repo, branch, err
}

// ---------------- Shared helpers ----------------

func decodeJSON(w http.ResponseWriter, r *http.Request, out any) bool {
	defer r.Body.Close()
	dec := json.NewDecoder(r.Body)
	dec.DisallowUnknownFields()
	if err := dec.Decode(out); err != nil {
		writeError(w, http.StatusBadRequest, "invalid json: "+err.Error())
		return false
	}
	return true
}

func writeJSON(w http.ResponseWriter, status int, v any) {
	w.Header().Set("Content-Type", "application/json")
	w.WriteHeader(status)
	_ = json.NewEncoder(w).Encode(v)
}

func writeError(w http.ResponseWriter, status int, msg string) {
	writeJSON(w, status, map[string]string{"error": msg})
}

func isReservedName(s string) bool {
	switch s {
	case "api", "admin", "storage", "git", "repos", ".", "..":
		return true
	default:
		return false
	}
}

func (s *Server) repoPath(owner, name string) string {
	return filepath.Join(s.storage, "repos", strings.ToLower(owner), strings.ToLower(name)+".git")
}

func gitInitBare(path string) error {
	if err := runGit("", "init", "--bare", path); err != nil {
		return err
	}
	return runGit("", "--git-dir", path, "symbolic-ref", "HEAD", "refs/heads/main")
}

func gitBranchExists(repoPath, branch string) bool {
	if !branchRE.MatchString(branch) {
		return false
	}
	cmd := exec.Command("git", "--git-dir", repoPath, "rev-parse", "--verify", "refs/heads/"+branch)
	return cmd.Run() == nil
}

func runGit(dir string, args ...string) error {
	cmd := exec.Command("git", args...)
	if dir != "" {
		cmd.Dir = dir
	}
	out, err := cmd.CombinedOutput()
	if err != nil {
		return fmt.Errorf("git %s failed: %s", strings.Join(args, " "), strings.TrimSpace(string(out)))
	}
	return nil
}