package render

import (
	"bytes"
	"fmt"
	"html/template"
	"io/fs"
	"path"

	"github.com/bnema/gordon/internal/server"
)

type Renderer struct {
	Template     *template.Template
	ParseError   error
	BuildVersion string
}

// Render function renders the template with the given data
func (r *Renderer) Render(data interface{}, a *server.App) (string, error) {
	if r.ParseError != nil {
		return "", fmt.Errorf("failed to parse template: %w", r.ParseError)

	}
	if r.Template == nil {
		return "", fmt.Errorf("template is nil")
	}
	// Type assert data to map[string]interface{} to add BuildVersion
	dataMap, ok := data.(map[string]interface{})
	if !ok {
		return "", fmt.Errorf("data is not a map[string]interface{}")
	}

	// Automatically add BuildVersion to the data map
	dataMap["BuildVersion"] = r.BuildVersion
	buf := new(bytes.Buffer)
	err := r.Template.Execute(buf, dataMap)
	if err != nil {
		return "", fmt.Errorf("failed to execute template: %w", err)
	}

	return buf.String(), nil
}

// GetHTMLRenderer function returns a new Renderer instance
func GetHTMLRenderer(mainPath string, filename string, fs fs.FS, a *server.App, fragmentsPath ...string) (*Renderer, error) {
	// Full path to the main template
	fullPath := path.Join(mainPath, filename)
	// Check if the file exists in the provided fs.FS using fs.Open
	file, err := fs.Open(fullPath)
	if err != nil {
		return nil, fmt.Errorf("failed to open %s: %w", filename, err)
	}
	file.Close()

	// Parse the main template
	tmpl, err := template.New(filename).ParseFS(fs, fullPath)
	if err != nil {
		return nil, fmt.Errorf("failed to parse %s: %w", filename, err)
	}

	// If a fragments path is provided, parse the fragment templates
	if len(fragmentsPath) > 0 && fragmentsPath[0] != "" {
		fragmentsGlob := path.Join(fragmentsPath[0], "*.gohtml")
		_, err = tmpl.ParseFS(fs, fragmentsGlob)
		if err != nil {
			return nil, fmt.Errorf("failed to parse fragments: %w", err)
		}
	}

	// Return the Renderer instance
	return &Renderer{
		Template:     tmpl,
		BuildVersion: a.Config.Build.BuildVersion,
	}, nil
}