package storage

import (
	"fmt"
	"os"
	"os/exec"
	"regexp"
	"strings"
)

var forbiddenFlagChars = regexp.MustCompile("[;&|$`\"<>\r\n\x00]")

type MoverConfig struct {
	Source      string
	Dest        string
	CleanMacOS  bool
	RemoveSrc   bool
	Inplace     bool
	ExtraFlags  []string
	DryRun      bool
}

func BuildPreviewArgs(cfg MoverConfig) ([]string, error) {
	if cfg.Source == "" || cfg.Dest == "" {
		return nil, fmt.Errorf("source and dest are required")
	}
	args := []string{
		"rsync",
		"-an",
		"--remove-source-files",
		"--out-format=%n",
		cfg.Source + "/",
		cfg.Dest + "/",
	}
	return args, nil
}

func BuildMoverArgs(cfg MoverConfig) ([]string, error) {
	if cfg.Source == "" || cfg.Dest == "" {
		return nil, fmt.Errorf("source and dest are required")
	}
	args := []string{"rsync", "-aAXv"}
	if !cfg.Inplace {
		args = append(args, "--inplace")
	}
	args = append(args, "--remove-source-files")
	if !cfg.DryRun {
		args = append(args, "--progress", "--info=progress2")
	}
	args = append(args, "--no-compress")
	args = append(args, cfg.ExtraFlags...)
	args = append(args, "--info=progress2")
	args = append(args, cfg.Source+"/", cfg.Dest+"/")
	return args, nil
}

func CleanMacOSJunk(root string) error {
	for _, pattern := range []string{".DS_Store", "._*"} {
		cmd := exec.Command("find", root, "-name", pattern, "-delete")
		if err := cmd.Run(); err != nil {
			return fmt.Errorf("clean junk %s: %w", pattern, err)
		}
	}
	return nil
}

func RemoveEmptyDirs(root string) error {
	cmd := exec.Command("find", root, "-mindepth", "1", "-type", "d", "-empty", "-delete")
	if err := cmd.Run(); err != nil {
		return fmt.Errorf("remove empty dirs: %w", err)
	}
	return nil
}

func ValidateMoverPaths(cfg MoverConfig) error {
	if cfg.Source == "" {
		return fmt.Errorf("source path is required")
	}
	if cfg.Dest == "" {
		return fmt.Errorf("destination path is required")
	}
	info, err := os.Stat(cfg.Source)
	if err != nil {
		return fmt.Errorf("source %s: %w", cfg.Source, err)
	}
	if !info.IsDir() {
		return fmt.Errorf("source %s: not a directory", cfg.Source)
	}
	info, err = os.Stat(cfg.Dest)
	if err != nil {
		return fmt.Errorf("destination %s: %w", cfg.Dest, err)
	}
	if !info.IsDir() {
		return fmt.Errorf("destination %s: not a directory", cfg.Dest)
	}
	return nil
}

func ParseExtraRsyncFlags(raw string) ([]string, error) {
	var out []string
	lines := strings.Split(raw, "\n")
	for i, line := range lines {
		line = strings.TrimSpace(line)
		if line == "" || strings.HasPrefix(line, "#") {
			continue
		}
		if !strings.HasPrefix(line, "-") {
			return nil, fmt.Errorf("line %d: flag must start with '-' (%q)", i+1, line)
		}
		if forbiddenFlagChars.MatchString(line) {
			return nil, fmt.Errorf("line %d: flag contains forbidden characters (%q)", i+1, line)
		}
		out = append(out, line)
	}
	return out, nil
}