package workon

import (
	"fmt"
	"os"
	"os/exec"
	"path/filepath"

	"gmgauthier.com/grokkit/internal/config"
	"gmgauthier.com/grokkit/internal/logger"
	"gmgauthier.com/grokkit/internal/todo" // created below
)

// Run executes the full transactional workon flow.
func Run(title, customMsg string, isFix, isComplete bool) error {
	if title == "" {
		return fmt.Errorf("todo_item_title is required")
	}

	// 1. Bootstrap todo structure if missing
	if err := todo.Bootstrap(); err != nil {
		return fmt.Errorf("todo bootstrap failed: %w", err)
	}

	if isComplete {
		return completeItem(title, isFix)
	}

	// 2. Handle todo or fix mode
	branchName := title
	mdPath := filepath.Join("todo", "doing", title+".md")

	if isFix {
		if err := createFixFile(mdPath, title); err != nil {
			return err
		}
	} else {
		if err := moveQueuedToDoing(title); err != nil {
			return err
		}
	}

	// 3. Create git branch
	if err := createGitBranch(branchName); err != nil {
		return fmt.Errorf("failed to create branch %s: %w", branchName, err)
	}

	// 4. Generate and append Work Plan
	if err := appendWorkPlan(mdPath, title); err != nil {
		return fmt.Errorf("failed to generate/append Work Plan: %w", err)
	}

	// 5. Commit
	commitMsg := customMsg
	if commitMsg == "" {
		commitMsg = fmt.Sprintf("Start working on %s", title)
	}
	if err := commitChanges(commitMsg); err != nil {
		return fmt.Errorf("commit failed: %w", err)
	}

	// 6. Optional post-steps (graceful)
	runCnaddIfAvailable(title)
	openIDEIfConfigured()

	logger.Info("workon transaction complete", "branch", branchName, "mode", map[bool]string{true: "fix", false: "todo"}[isFix])
	return nil
}

// Placeholder implementations — split out to internal/todo in next batch if you prefer
func moveQueuedToDoing(title string) error {
	src := filepath.Join("todo", "queued", title+".md")
	dst := filepath.Join("todo", "doing", title+".md")
	if err := os.Rename(src, dst); err != nil {
		return fmt.Errorf("move %s -> doing failed: %w", title, err)
	}
	return nil
}

func createFixFile(path, title string) error {
	content := fmt.Sprintf("# %s\n\n## Work Plan\n\n", title)
	return os.WriteFile(path, []byte(content), 0644)
}

func createGitBranch(name string) error {
	return exec.Command("git", "checkout", "-b", name).Run()
}

func appendWorkPlan(path, title string) error {
	// TODO: Replace stub with real Grok call (use existing Grok client pattern from other cmds)
	plan := "\n## Work Plan\n\n1. Analyze requirements\n2. Implement changes\n3. Test\n4. Commit\n"
	f, err := os.OpenFile(path, os.O_APPEND|os.O_WRONLY, 0644)
	if err != nil {
		return err
	}
	defer f.Close()
	_, err = f.WriteString(plan)
	return err
}

func commitChanges(msg string) error {
	if err := exec.Command("git", "add", "todo/").Run(); err != nil {
		return err
	}
	return exec.Command("git", "commit", "-m", msg).Run()
}

func completeItem(title string, isFix bool) error {
	// TODO: move to completed/, update index README for todos, commit
	logger.Info("complete mode not yet implemented")
	return nil
}

func runCnaddIfAvailable(title string) {
	if _, err := exec.LookPath("cnadd"); err == nil {
		_ = exec.Command("cnadd", "log", fmt.Sprintf("started work on %s", title)).Run()
	}
}

func openIDEIfConfigured() {
	cfg := config.Load() // assuming config package pattern
	if cfg.IDE != "" {
		// exec open command with current branch or file
		_ = exec.Command("sh", "-c", cfg.IDE).Run() // placeholder
	}
}