package cmd

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

	"github.com/spf13/cobra"

	"dirmd/internal/config"
	"dirmd/internal/drive"
	"dirmd/internal/renderer"
	"dirmd/internal/walker"
)

var (
	rootCmd = &cobra.Command{
		Use:   "dirmd [flags] <directory>",
		Short: "Generate markdown documentation from directory structure",
		Long: `dirmd walks a directory and generates a markdown file with:

- Directory tree structure
- All readable text files with their contents

Examples:

  # Create new documentation
  dirmd -o output.md ~/repos/myproject

  # Append a single file
  dirmd -a -i README.md -o existing.md

  # Append another directory
  dirmd -a -o existing.md ~/repos/anotherproject

  # Overwrite existing local file
  dirmd -o output.md ~/repos/myproject -f

  # Generate with vertical slices (root + one file per top-level dir)
  dirmd -o output.md ~/repos/myproject --vertical-slices

  # Generate and upload to Proton Drive
  dirmd -o output.md ~/repos/myproject --proton-drive

  # Generate and upload to a specific remote path
  dirmd -o output.md ~/repos/myproject --proton-drive --drive-path /my-files/docs/api.md`,
		RunE: run,
	}

	outputPath     string
	appendMode     bool
	force          bool
	singleFile     string
	maxSize        int64
	maxDepth       int
	ignorePatterns []string
	extensions     []string
	protonDrive    bool
	drivePath      string
	verticalSlices bool
)

func Execute() {
	if err := rootCmd.Execute(); err != nil {
		os.Exit(1)
	}
}

func init() {
	rootCmd.PersistentFlags().StringVarP(&outputPath, "output", "o", "", "output markdown file path (required)")
	rootCmd.Flags().BoolVarP(&appendMode, "append", "a", false, "append to existing output file")
	rootCmd.Flags().BoolVarP(&force, "force", "f", false, "overwrite existing output file (non-append mode)")
	rootCmd.Flags().StringVarP(&singleFile, "input-file", "i", "", "single file input (append mode only)")
	rootCmd.Flags().Int64Var(&maxSize, "max-size", config.DefaultMaxSize, "max file size in bytes")
	rootCmd.Flags().IntVar(&maxDepth, "max-depth", config.DefaultMaxDepth, "max directory recursion depth")
	rootCmd.Flags().StringArrayVar(&ignorePatterns, "ignore", nil, "additional ignore patterns (glob)")
	rootCmd.Flags().StringArrayVar(&extensions, "extensions", nil, "additional file extensions to skip (repeatable)")
	rootCmd.Flags().BoolVar(&protonDrive, "proton-drive", false, "upload output to Proton Drive after writing locally")
	rootCmd.Flags().StringVar(&drivePath, "drive-path", "", "full remote path on Proton Drive (e.g. /my-files/md/report.md). Requires --proton-drive")
	rootCmd.Flags().BoolVar(&verticalSlices, "vertical-slices", false, "split output into root file + one markdown per top-level directory")

	rootCmd.MarkPersistentFlagRequired("output")
}

func run(cmd *cobra.Command, args []string) error {
	if drivePath != "" && !protonDrive {
		return fmt.Errorf("--drive-path requires --proton-drive")
	}

	if verticalSlices && appendMode {
		return fmt.Errorf("--vertical-slices cannot be used with --append")
	}

	if verticalSlices && singleFile != "" {
		return fmt.Errorf("--vertical-slices cannot be used with --input-file")
	}

	cfg := &config.Config{
		OutputPath:     outputPath,
		AppendMode:     appendMode,
		Force:          force,
		MaxSize:        maxSize,
		MaxDepth:       maxDepth,
		Ignores:        append(config.DefaultIgnores, ignorePatterns...),
		Extensions:     append(config.DefaultExts, extensions...),
		ProtonDrive:    protonDrive,
		DrivePath:      drivePath,
		VerticalSlices: verticalSlices,
	}

	if singleFile != "" {
		cfg.InputPath = singleFile
		cfg.SingleFile = true
		if !appendMode {
			return fmt.Errorf("single file input (-i) requires append mode (-a)")
		}
	} else {
		if len(args) < 1 {
			return fmt.Errorf("directory argument is required when -i is not used")
		}
		cfg.InputPath = args[0]
	}

	abs, err := filepath.Abs(cfg.InputPath)
	if err != nil {
		return fmt.Errorf("failed to resolve absolute path: %w", err)
	}
	cfg.AbsRoot = abs

	if !appendMode {
		if _, err := os.Stat(outputPath); err == nil && !force {
			return fmt.Errorf("output file %s already exists (use -f to overwrite or -a to append)", outputPath)
		}
	}

	result, err := walker.Run(cfg)
	if err != nil {
		return err
	}

	if len(result.Entries) == 0 {
		return fmt.Errorf("no readable text files found in %s", cfg.AbsRoot)
	}

	if verticalSlices {
		generated, err := renderer.WriteSlices(result, outputPath)
		if err != nil {
			return err
		}

		fmt.Fprintf(os.Stderr, "generated %d files\n", len(generated))

		if protonDrive {
			if err := drive.CheckAuth(); err != nil {
				fmt.Fprintf(os.Stderr, "error: %v\n", err)
				fmt.Fprintln(os.Stderr, "local files were written successfully, but upload was skipped")
				return err
			}

			for _, path := range generated {
				if err := drive.Upload(path, "/my-files/md/"+filepath.Base(path)); err != nil {
					fmt.Fprintf(os.Stderr, "error uploading %s: %v\n", path, err)
				} else {
					fmt.Fprintf(os.Stderr, "uploaded %s to Proton Drive\n", path)
				}
			}
		}

		return nil
	}

	if err := renderer.Write(result, outputPath, appendMode, cfg.SingleFile); err != nil {
		return err
	}

	fmt.Fprintf(os.Stderr, "wrote %d entries to %s\n", len(result.Entries), outputPath)

	if protonDrive {
		remotePath := drivePath
		if remotePath == "" {
			remotePath = "/my-files/md/" + filepath.Base(outputPath)
		}

		if err := drive.CheckAuth(); err != nil {
			fmt.Fprintf(os.Stderr, "error: %v\n", err)
			fmt.Fprintln(os.Stderr, "local file was written successfully, but upload was skipped")
			return err
		}

		if err := drive.Upload(outputPath, remotePath); err != nil {
			fmt.Fprintf(os.Stderr, "error: %v\n", err)
			fmt.Fprintln(os.Stderr, "local file was written successfully, but upload failed")
			return err
		}

		fmt.Fprintf(os.Stderr, "uploaded %s to %s on Proton Drive\n", outputPath, remotePath)
	}

	return nil
}