//go:build mage

package main

import (
	"fmt"
	"io/fs"
	"os"
	"path/filepath"
	"slices"
	"strings"

	"github.com/magefile/mage/sh"
)

// Files ensure that the configuration files in the managed directory is up to date and
// ensures that they are symlinked correctly to the files in the user's home configuration
// directory.
func Files() error {
	homeConfigDirectory, err := os.UserConfigDir()
	if err != nil {
		return fmt.Errorf("unable to get the user's home configuration directory: %w", err)
	}

	config, err := newConfig()
	if err != nil {
		return fmt.Errorf("unable to load the configuration: %w", err)
	}

	managedConfig := managedConfigSet(config.ManagedConfigurations)

	if err = filepath.WalkDir(rootFilesDir, manageFilesFunc(homeConfigDirectory, managedConfig)); err != nil {
		return fmt.Errorf("received an error while processing the files: %w", err)
	}

	return nil
}

func manageFilesFunc(homeConfigDirectory string, managedConfig map[string]struct{}) fs.WalkDirFunc {
	return func(path string, d fs.DirEntry, err error) error {
		if err != nil {
			return err
		}

		if path == rootFilesDir {
			return nil
		}

		relativePath := strings.TrimPrefix(path, rootFilesDir+"/")

		appConfigName := strings.SplitN(relativePath, "/", 2)[0]

		if _, exists := managedConfig[appConfigName]; !exists {
			return nil
		}

		managedPath := filepath.Join(rootManagedDir, relativePath)
		configPath := filepath.Join(homeConfigDirectory, relativePath)

		if d.IsDir() {
			dirs := []string{managedPath, configPath}

			for _, dir := range slices.All(dirs) {
				if err := ensureDirectory(dir); err != nil {
					return fmt.Errorf("unable to ensure the existence of the directory %q: %w", dir, err)
				}
			}

			return nil
		}

		fmt.Println("Processing file:", relativePath)

		if err := sh.Copy(managedPath, path); err != nil {
			return fmt.Errorf("unable to copy %s to %s: %w", path, managedPath, err)
		}

		if err := ensureSymlink(managedPath, configPath); err != nil {
			return err
		}

		return nil
	}
}