package walk

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

	"codeflow.dananglin.me.uk/linux-home/manager/magefiles/internal/config"
	"codeflow.dananglin.me.uk/linux-home/manager/magefiles/internal/utilities"
)

func RenderTemplates(
	cfg config.Config,
	homeConfigDirectory string,
	rootDir string,
	rootManagedDir string,
	validationFunc func(string) bool,
) fs.WalkDirFunc {
	return func(path string, d fs.DirEntry, err error) error {
		if err != nil {
			return err
		}

		if path == rootDir {
			return nil
		}

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

		if validationFunc != nil {
			if !validationFunc(relativePath) {
				return nil
			}
		}

		if d.IsDir() {
			managedDir := filepath.Join(rootManagedDir, relativePath)
			configDir := filepath.Join(homeConfigDirectory, relativePath)

			dirs := []string{managedDir, configDir}

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

			return nil
		}

		managedPath := filepath.Join(rootManagedDir, strings.TrimSuffix(relativePath, utilities.TemplateExtension))
		configPath := filepath.Join(homeConfigDirectory, strings.TrimSuffix(relativePath, utilities.TemplateExtension))

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

		if err := utilities.RenderTemplate(cfg, path, managedPath); err != nil {
			return fmt.Errorf(
				"unable to generate %s from template %s: %w",
				managedPath,
				path,
				err,
			)
		}

		if err := utilities.EnsureSymlink(managedPath, configPath); err != nil {
			return err
		}

		return nil
	}
}