package app

import (
	"context"
	"errors"
	"flag"
	"fmt"
	"net/http"
	"strings"
	"time"
)

func cliPR(args []string) error {
	if len(args) < 1 {
		return errors.New("usage: gitocean pr <create|list|view|diff|checkout|comment|comments|close|merge>")
	}
	switch args[0] {
	case "create":
		return cliPRCreate(args[1:])
	case "list":
		return cliPRList(args[1:])
	case "view":
		return cliPRView(args[1:])
	case "diff":
		return cliPRDiff(args[1:])
	case "checkout":
		return cliPRCheckout(args[1:])
	case "comment":
		return cliPRComment(args[1:])
	case "comments":
		return cliPRComments(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
	}
	printPR(out)
	return nil
}

func cliPRList(args []string) error {
	jsonOut := removeBoolFlag(&args, "--json")
	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
	}
	if jsonOut {
		printJSON(out)
		return nil
	}
	for _, pr := range out {
		fmt.Printf("#%-4d %-8s %-30s %s/%s:%s -> %s\n", pr.Number, pr.Status, pr.Title, pr.SourceOwner, pr.SourceRepo, pr.SourceBranch, pr.TargetBranch)
	}
	return nil
}

func cliPRView(args []string) error {
	jsonOut := removeBoolFlag(&args, "--json")
	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
	}
	if jsonOut {
		printJSON(out)
		return nil
	}
	printPR(out)
	return nil
}

func cliPRDiff(args []string) error {
	if len(args) != 2 {
		return errors.New("usage: gitocean pr diff 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
	}
	text, err := apiTextRequest(context.Background(), server, fmt.Sprintf("/api/repos/%s/%s/pulls/%s/diff", owner, repo, args[1]), token)
	if err != nil {
		return err
	}
	fmt.Print(text)
	return nil
}

func cliPRCheckout(args []string) error {
	if len(args) != 2 {
		return errors.New("usage: gitocean pr checkout 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 pr PullRequest
	if err := apiRequest(context.Background(), server, http.MethodGet, fmt.Sprintf("/api/repos/%s/%s/pulls/%s", owner, repo, args[1]), token, nil, &pr); err != nil {
		return err
	}
	branch := "pr-" + args[1]
	remote := repoCloneURL(server, pr.SourceOwner, pr.SourceRepo)
	if err := runGit("", "fetch", remote, pr.SourceBranch+":"+branch); err != nil {
		_ = runGit("", "branch", "-D", branch)
		if err := runGit("", "fetch", remote, pr.SourceBranch+":"+branch); err != nil {
			return err
		}
	}
	return runGit("", "checkout", branch)
}

func cliPRComment(args []string) error {
	if len(args) < 3 {
		return errors.New("usage: gitocean pr comment OWNER/REPO NUMBER \"text\"")
	}
	owner, repo, err := splitOwnerRepo(args[0])
	if err != nil {
		return err
	}
	cfg, err := loadConfig()
	if err != nil {
		return err
	}
	body := strings.Join(args[2:], " ")
	var out PRComment
	if err := apiRequest(context.Background(), cfg.Server, http.MethodPost, fmt.Sprintf("/api/repos/%s/%s/pulls/%s/comments", owner, repo, args[1]), cfg.Token, map[string]string{"body": body}, &out); err != nil {
		return err
	}
	fmt.Printf("Commented as %s\n", out.Author)
	return nil
}

func cliPRComments(args []string) error {
	if len(args) != 2 {
		return errors.New("usage: gitocean pr comments 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 []PRComment
	if err := apiRequest(context.Background(), server, http.MethodGet, fmt.Sprintf("/api/repos/%s/%s/pulls/%s/comments", owner, repo, args[1]), token, nil, &out); err != nil {
		return err
	}
	for _, c := range out {
		fmt.Printf("%s by %s:\n%s\n\n", c.CreatedAt.Format(time.RFC3339), c.Author, c.Body)
	}
	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
	}
	printPR(out)
	return nil
}