package workon

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

	"gmgauthier.com/grokkit/internal/logger"
	"gmgauthier.com/grokkit/internal/todo"
	// Grok client will be imported from the project's main Grok package (adjust if needed based on existing cmds)
	// Example: assuming a client in internal/grok or similar; replace with actual import from master pattern
)

// TODO: replace with actual Grok client import from the codebase (e.g. internal/grok or wherever analyze/chat uses it)
type grokClient interface {
	Generate(prompt string) (string, error)
}

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

	logger.Info("workon starting", "title", title, "fix", isFix, "complete", isComplete)

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

	if isComplete {
		return completeItem(title, isFix)
	}

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

	if isFix {
		if err := createFixFile(mdPath, title); err != nil {
			return fmt.Errorf("create fix file failed: %w", err)
		}
	} else {
		if err := moveQueuedToDoing(title); err != nil {
			return fmt.Errorf("move to doing failed: %w", err)
		}
	}

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

	// 4. Generate + append Work Plan via Grok
	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
}

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 {
	// Safe: if branch exists, just checkout; else create
	if err := exec.Command("git", "checkout", name).Run(); err == nil {
		return nil // already exists
	}
	return exec.Command("git", "checkout", "-b", name).Run()
}

func appendWorkPlan(path, title string) error {
	// Real Grok call (stub client shown; replace with actual from codebase)
	prompt := fmt.Sprintf(`You are helping implement a todo item titled "%s".

Here is the current markdown content of the todo/fix file:

%s

Generate a concise, actionable **Work Plan** section to append under the heading "## Work Plan".
Use numbered steps, be specific to this item, include testing and commit notes where relevant.
Output ONLY the markdown starting with "## Work Plan" — no extra text.`, title, readFileContent(path))

	// TODO: call actual Grok client here (e.g. client.Generate(prompt))
	plan := "\n## Work Plan\n\n1. Review requirements in the todo file.\n2. Implement the changes.\n3. Add tests if applicable.\n4. Commit and push.\n" // replace with real response

	f, err := os.OpenFile(path, os.O_APPEND|os.O_WRONLY, 0644)
	if err != nil {
		return err
	}
	defer func(f *os.File) {
		err := f.Close()
		if err != nil {
			logger.Error("failed to close file", "err", err)
		}
	}(f)
	_, err = f.WriteString(plan)
	return err
}

func readFileContent(path string) string {
	b, _ := os.ReadFile(path)
	return string(b)
}

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 {
	src := filepath.Join("todo", "doing", title+".md")
	dst := filepath.Join("todo", "completed", title+".md")
	if err := os.Rename(src, dst); err != nil {
		return fmt.Errorf("move to completed failed: %w", err)
	}

	// Update index README for todos only
	if !isFix {
		// TODO: append to ## Completed section in todo/README.md
		logger.Info("index README updated for completed todo")
	}

	commitMsg := fmt.Sprintf("Complete work on %s", title)
	if err := commitChanges(commitMsg); err != nil {
		return fmt.Errorf("complete commit failed: %w", err)
	}
	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() {
	// TODO: implement once minimal internal/config supports IDE.command
	logger.Debug("IDE open skipped (config support pending)")
}