package cmd

import (
	"bufio"
	"fmt"
	"os"
	"path/filepath"
	"strings"

	"github.com/spf13/cobra"
	"github.com/warrenronsiek/ctask/internal/config"
	"github.com/warrenronsiek/ctask/internal/workspace"
)

var deleteCmd = &cobra.Command{
	Use:          "delete <query>",
	Short:        "Permanently remove a workspace directory",
	Args:         cobra.ExactArgs(1),
	SilenceUsage: true,
	RunE:         runDelete,
}

var (
	deleteForce bool
	deleteAll   bool
)

func init() {
	deleteCmd.Flags().BoolVarP(&deleteForce, "force", "f", false, "Skip confirmation prompt")
	deleteCmd.Flags().BoolVarP(&deleteAll, "all", "a", false, "Include archived workspaces in query resolution")
	rootCmd.AddCommand(deleteCmd)
}

func runDelete(cmd *cobra.Command, args []string) error {
	root := config.ResolveRoot()
	ws := resolveOne(root, args[0], deleteAll)

	// Active workspace protection — two checks, BOTH run before any mutation.
	//
	// Check 1: CTASK_WORKSPACE env var matches (catches same-session delete attempts)
	// Check 2: .ctask/manifest-start.json exists (catches cross-terminal delete attempts
	//          because the manifest is only present during a live session)
	//
	// Either check triggers immediate refusal with no side effects.
	absTarget, _ := filepath.Abs(ws.Path)

	activeWs := os.Getenv("CTASK_WORKSPACE")
	if activeWs != "" {
		absActive, _ := filepath.Abs(activeWs)
		if strings.EqualFold(absTarget, absActive) {
			fmt.Fprintln(os.Stderr, "Cannot delete the active workspace. Exit the session first.")
			os.Exit(1)
		}
	}

	manifestPath := filepath.Join(ws.Path, ".ctask", "manifest-start.json")
	if _, err := os.Stat(manifestPath); err == nil {
		fmt.Fprintln(os.Stderr, "Cannot delete a workspace with an active session. Exit the session first.")
		os.Exit(1)
	}

	// --- Past this point, we are confident no session is active. ---

	relPath := workspace.RelativePath(root, ws.Path)

	// Gather contents summary (best-effort, read-only)
	fileCount, totalSize := summarizeContents(ws.Path)

	fmt.Println()
	fmt.Printf("  Workspace: %s\n", relPath)
	fmt.Printf("  Files: %d (%s)\n", fileCount, formatSize(totalSize))

	// Check if this is the most recently updated workspace.
	// v0.3: union tasks and projects so the "most recent" check spans both types.
	tasks, _ := workspace.ListWorkspaces(root, workspace.ListOpts{
		IncludeArchived: false,
		Limit:           0,
	})
	projects, _ := workspace.ListWorkspaces(root, workspace.ListOpts{
		IncludeArchived: false,
		Projects:        true,
		Limit:           0,
	})
	results := append(tasks, projects...)
	if len(results) > 0 {
		best := results[0]
		for _, r := range results[1:] {
			if r.Meta.UpdatedAt.After(best.Meta.UpdatedAt) {
				best = r
			}
		}
		absBest, _ := filepath.Abs(best.Path)
		if strings.EqualFold(absTarget, absBest) {
			fmt.Println()
			fmt.Println("  Note: This was your most recent workspace.")
		}
	}

	fmt.Println()

	if !deleteForce {
		fmt.Print("  Delete this workspace? This cannot be undone. [y/N] ")
		reader := bufio.NewReader(os.Stdin)
		answer, _ := reader.ReadString('\n')
		answer = strings.TrimSpace(strings.ToLower(answer))
		if answer != "y" && answer != "yes" {
			fmt.Println("  Cancelled.")
			return nil
		}
	}

	if err := os.RemoveAll(ws.Path); err != nil {
		return fmt.Errorf("deleting workspace: %w", err)
	}

	fmt.Println()
	fmt.Printf("[ctask] deleted: %s\n", relPath)
	return nil
}

// summarizeContents counts files and total size in a directory.
// Best-effort: errors on individual files are skipped.
func summarizeContents(dir string) (int, int64) {
	count := 0
	var total int64
	filepath.Walk(dir, func(path string, info os.FileInfo, err error) error {
		if err != nil {
			return nil // skip errors
		}
		if !info.IsDir() {
			count++
			total += info.Size()
		}
		return nil
	})
	return count, total
}

// formatSize returns a human-readable file size.
func formatSize(bytes int64) string {
	if bytes < 1024 {
		return fmt.Sprintf("%d B", bytes)
	}
	kb := float64(bytes) / 1024
	if kb < 1024 {
		return fmt.Sprintf("%.0f KB", kb)
	}
	mb := kb / 1024
	return fmt.Sprintf("%.1f MB", mb)
}