package cmd

import (
	"context"
	"errors"
	"flag"
	"fmt"
	"os"
	"strings"

	"github.com/peterbourgon/ff/v3/ffcli"
)

func (h *Handler) Branch() *ffcli.Command {
	fs := flag.NewFlagSet("branch", flag.ContinueOnError)
	noFetchFlag := fs.Bool("no-fetch", false, "Skip fetching")
	fs.BoolVar(noFetchFlag, "nf", *noFetchFlag, "--no-fetch")
	baseFlag := fs.String("base", "main", "Ref to base from")
	fs.StringVar(baseFlag, "b", *baseFlag, "--base")
	listFlag := fs.Bool("list", false, "List branches available")
	fs.BoolVar(listFlag, "l", *listFlag, "--list")
	ideFlag := fs.Bool("ide", false, "Open an IDE for the new branch")
	fs.BoolVar(ideFlag, "i", *ideFlag, "--ide")
	return &ffcli.Command{
		Name:       "branch",
		FlagSet:    fs,
		ShortUsage: "branch --base [ref=main] <name>",
		ShortHelp:  "branch creates a new branch called `name` based on `base`",
		Exec: func(ctx context.Context, args []string) error {
			if err := h.checkInit(); err != nil {
				return err
			}

			if *listFlag {
				dirs, err := os.ReadDir(h.Config.Workspace())
				if err != nil {
					return err
				}
				for _, dir := range dirs {
					if !dir.IsDir() {
						continue
					}
					fmt.Println(dir.Name())
				}
				return nil
			}

			if len(args) < 1 {
				return errors.New("branch requires a name")
			}

			name := args[0]
			base := *baseFlag
			switch {
			case strings.HasPrefix(base, "o/"):
				base = "origin/" + strings.TrimPrefix(base, "o/")
			case strings.HasPrefix(base, "u/"):
				base = "upstream/" + strings.TrimPrefix(base, "u/")
			}
			if (!strings.HasPrefix(base, "upstream") || !strings.HasPrefix(base, "origin")) && !strings.HasPrefix(base, "pr-") {
				base = fmt.Sprintf("upstream/%s", base)
			}

			if !*noFetchFlag {
				h.fetch(ctx)
			}

			if err := h.run(ctx, "git", "worktree", "add", "-B", name, h.Config.WorkspaceBranch(name), base); err != nil {
				return err
			}

			if *ideFlag {
				return h.IDE().ParseAndRun(ctx, []string{name})
			}

			return nil
		},
	}
}