package cmd

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

	"github.com/spf13/cobra"

	"dirmd/internal/config"
	"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`,
		RunE: run,
	}

	outputPath     string
	appendMode     bool
	singleFile     string
	maxSize        int64
	maxDepth       int
	ignorePatterns []string
	extensions     []string
)

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().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.MarkPersistentFlagRequired("output")
}

func run(cmd *cobra.Command, args []string) error {
	cfg := &config.Config{
		OutputPath: outputPath,
		AppendMode: appendMode,
		MaxSize:    maxSize,
		MaxDepth:   maxDepth,
		Ignores:    append(config.DefaultIgnores, ignorePatterns...),
		Extensions: append(config.DefaultExts, extensions...),
	}

	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

	// Non-append mode: output must not exist
	if !appendMode {
		if _, err := os.Stat(outputPath); err == nil {
			return fmt.Errorf("output file %s already exists (use -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 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)
	return nil
}