package app

import (
	"database/sql"
	"errors"
	"flag"
	"fmt"
	"net/http"
	"os"
	"path/filepath"
	"strings"

	"gitocean/internal/dbutil"
)

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

func runServer(args []string) error {
	fs := flag.NewFlagSet("server", flag.ExitOnError)
	configFile := fs.String("config", defaultServerConfigPath(), "server config file")
	addr := fs.String("addr", "", "HTTP listen address")
	dsn := fs.String("dsn", os.Getenv("GITOOCEAN_DSN"), "MySQL DSN")
	storage := fs.String("storage", "", "storage directory")
	publicURL := fs.String("public-url", "", "public server URL")
	if err := fs.Parse(args); err != nil {
		return err
	}

	cfg, _ := loadServerConfig(*configFile)
	if *addr != "" {
		cfg.Addr = *addr
	}
	if *dsn != "" {
		cfg.MySQLDSN = *dsn
	}
	if *storage != "" {
		cfg.Storage = *storage
	}
	if *publicURL != "" {
		cfg.PublicURL = *publicURL
	}
	if cfg.Addr == "" {
		cfg.Addr = ":8080"
	}
	if cfg.Storage == "" {
		cfg.Storage = defaultStorage
	}
	if cfg.PublicURL == "" {
		cfg.PublicURL = defaultServerURL
	}
	if cfg.MySQLDSN == "" {
		return errors.New("--dsn, GITOOCEAN_DSN, or server config mysql_dsn is required; run gitocean init")
	}

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

	s := &Server{db: db, storage: cfg.Storage, publicURL: strings.TrimRight(cfg.PublicURL, "/")}
	fmt.Printf("gitocean listening on %s, storage=%s, public_url=%s\n", cfg.Addr, cfg.Storage, s.publicURL)
	return http.ListenAndServe(cfg.Addr, s)
}

func openMySQLAndCreateDatabaseIfMissing(dsn string) (*sql.DB, error) {
	return dbutil.OpenMySQLAndCreateDatabaseIfMissing(dsn)
}

func quoteMySQLIdentifier(name string) string {
	return dbutil.QuoteMySQLIdentifier(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,
			is_admin BOOLEAN NOT NULL DEFAULT false,
			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,
			description TEXT NOT NULL,
			default_branch VARCHAR(200) NOT NULL DEFAULT 'main',
			archived BOOLEAN NOT NULL DEFAULT false,
			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 repository_collaborators (
			id BIGINT AUTO_INCREMENT PRIMARY KEY,
			repository_id BIGINT NOT NULL,
			user_id BIGINT NOT NULL,
			role ENUM('read','write') NOT NULL,
			created_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
			UNIQUE KEY uniq_repo_user (repository_id, user_id),
			CONSTRAINT fk_collab_repo FOREIGN KEY (repository_id) REFERENCES repositories(id) ON DELETE CASCADE,
			CONSTRAINT fk_collab_user FOREIGN KEY (user_id) REFERENCES users(id) ON DELETE CASCADE
		) 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`,
		`CREATE TABLE IF NOT EXISTS pull_request_comments (
			id BIGINT AUTO_INCREMENT PRIMARY KEY,
			pull_request_id BIGINT NOT NULL,
			author_user_id BIGINT NOT NULL,
			body TEXT NOT NULL,
			created_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
			updated_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
			INDEX idx_pr_comments_pr (pull_request_id),
			CONSTRAINT fk_pr_comments_pr FOREIGN KEY (pull_request_id) REFERENCES pull_requests(id) ON DELETE CASCADE,
			CONSTRAINT fk_pr_comments_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
		}
	}
	alterations := []string{
		`ALTER TABLE users ADD COLUMN is_admin BOOLEAN NOT NULL DEFAULT false`,
		`ALTER TABLE repositories ADD COLUMN description TEXT NULL`,
		`ALTER TABLE repositories ADD COLUMN default_branch VARCHAR(200) NOT NULL DEFAULT 'main'`,
		`ALTER TABLE repositories ADD COLUMN archived BOOLEAN NOT NULL DEFAULT false`,
	}
	for _, stmt := range alterations {
		if _, err := db.Exec(stmt); err != nil && !isDuplicateColumnError(err) {
			return err
		}
	}
	return nil
}