package templates

import (
	"context"
	"fmt"
	"log/slog"
	"os"
	"path"
	"strings"
	"text/template"
	"time"

	"arimelody.space/melody-vod-manager/scanner"
)



type (
	TextTemplates struct {
		Title *template.Template
		Description *template.Template
		DefaultTags []string
	}

	TextTemplateData struct {
		Title string
		Part uint
		Date time.Time
		Category *scanner.Category
	}
)

const DefaultTitleTemplate =
"{{.Title}} - {{FormatTime .Date \"02 Jan 2006\"}}"
const DefaultDescriptionTemplate =
"Streamed on {{FormatTime .Date \"02 January 2006\"}}"

func FetchTemplates(ctx context.Context, templateDir string) (*TextTemplates, error) {
	tmpl := TextTemplates{}
	logger := slog.Default().WithGroup("TEMPLATE")

	var tagsPath = path.Join(templateDir, "tags.txt")
	var titlePath = path.Join(templateDir, "title.txt")
	var descriptionPath = path.Join(templateDir, "description.txt")

	// tags
	if tagsFile, err := os.ReadFile(tagsPath); err == nil {
		tmpl.DefaultTags = strings.Split(string(tagsFile), "\n")
	} else {
		if !os.IsNotExist(err) { return nil, err }

		logger.Info(fmt.Sprintf(
			"%s not found. No default tags will be used.",
			tagsPath,
		))
		tmpl.DefaultTags = []string{}
	}

	// title
	titleTemplate := template.New("title").Funcs(templateFuncs)
	if titleFile, err := os.ReadFile(titlePath); err == nil {
		tmpl.Title, err = titleTemplate.Parse(string(titleFile))
		if err != nil {
			return nil, fmt.Errorf("failed to parse title template: %v", err)
		}
	} else {
		if !os.IsNotExist(err) { return nil, err }

		logger.Info(
			fmt.Sprintf(
				"%s not found. Falling back to default template:",
				titlePath,
			),
			"template",
			DefaultTitleTemplate,
		)
		tmpl.Title, err = titleTemplate.Parse(DefaultTitleTemplate)
		if err != nil { panic(err) }

		os.WriteFile(titlePath, []byte(DefaultTitleTemplate), 0644)
	}

	// description
	descriptionTemplate := template.New("description").Funcs(templateFuncs)
	if descriptionFile, err := os.ReadFile(descriptionPath); err == nil {
		tmpl.Description, err = descriptionTemplate.Parse(string(descriptionFile))
		if err != nil {
			return nil, fmt.Errorf("failed to parse description template: %v", err)
		}
	} else {
		if !os.IsNotExist(err) { return nil, err }

		logger.Info(
			fmt.Sprintf(
				"%s not found. Falling back to default template:",
				descriptionPath,
			),
			"template",
			DefaultDescriptionTemplate,
		)
		tmpl.Description, err = descriptionTemplate.Parse(DefaultDescriptionTemplate)
		if err != nil { panic(err) }

		os.WriteFile(descriptionPath, []byte(DefaultDescriptionTemplate), 0644)
	}

	return &tmpl, nil
}