import_func.go

package templit

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

// ImportFunc returns a function that can be used as a template function to import and process a template from a remote git repository.
// ImportFunc allows embedding content from a remote repository into a Go template.
//
// Steps to use:
//  1. Add the function to the FuncMap.
//  2. Use the following syntax within your template:
//     ```
//     {{ import "<host>/<owner>/<repo>/<path>@<tag_or_hash_or_branch>" "<path_to_genrate_files>" . }}
//     {{ import "<host>/<owner>/<repo>/<path>#<block>@<tag_or_hash_or_branch>" "<path_to_genrate_files>" . }}
//     ```
//
// Placeholders:
//   - `<host>`: Repository hosting service (e.g., "github.com").
//   - `<owner>`: Repository owner or organization.
//   - `<repo>`: Repository name.
//   - `<path>`: Path to the desired file or directory within the repository.
//   - `<tag_or_hash_or_branch>`: Specific Git reference (tag, commit hash, or branch name).
func (e *Executor) ImportFunc(outputDir string) func(repoAndTag, destPath string, data interface{}) (string, error) {
	return func(repoAndTag, destPath string, data interface{}) (string, error) {
		const tempDirPrefix = "temp_clone_"

		depInfo, err := ParseDepURL(repoAndTag)
		if err != nil {
			return "", fmt.Errorf("failed to parse embed URL: %w", err)
		}

		tempDir, err := os.MkdirTemp("", tempDirPrefix)
		if err != nil {
			return "", fmt.Errorf("failed to create temp dir: %w", err)
		}
		defer os.RemoveAll(tempDir) // Cleanup

		if err := e.git.Clone(depInfo.Host, depInfo.Owner, depInfo.Repo, tempDir); err != nil {
			return "", fmt.Errorf("failed to clone repo: %w", err)
		}

		if depInfo.Tag != "" && depInfo.Tag != e.git.DefaultBranch() {
			err = e.git.Checkout(tempDir, depInfo.Tag)
			if err != nil {
				return "", fmt.Errorf("failed to checkout ref %s: %w", depInfo.Tag, err)
			}
		}

		sourcePath := filepath.Join(tempDir, depInfo.Path)
		outputPath := filepath.Join(outputDir, destPath)

		// check if path is a file
		if info, err := os.Stat(sourcePath); err == nil && !info.IsDir() {
			// parse the file
			if err := e.ParsePath(filepath.Dir(sourcePath)); err != nil {
				return "", fmt.Errorf("failed to create executor: %w", err)
			}

			// render the file
			string, err := e.Render(sourcePath, data)
			if err != nil {
				return "", fmt.Errorf("failed to render template: %w", err)
			}

			// write the file
			if err := os.WriteFile(filepath.Join(outputPath, filepath.Base(depInfo.Path)), []byte(string), 0644); err != nil {
				return "", fmt.Errorf("failed to write file: %w", err)
			}

			return "", nil
		}

		if err := e.WalkAndProcessDir(sourcePath, outputPath, data); err != nil {
			return "", fmt.Errorf("failed to process template: %w", err)
		}

		return "", nil
	}
}