package webrender

import (
	"fmt"
	"html/template"
	"io"
	"net/url"
	"strconv"
	"sync"

	apptemplates "git.iioio.com/freefire/jiang13-forum/templates"
)

var (
	loadOnce sync.Once
	tpl      *template.Template
	loadErr  error
)

func funcMap() template.FuncMap {
	return template.FuncMap{
		"sortURL": func(boardID uint, sort string) string {
			q := url.Values{}
			if sort != "" && sort != "latest" {
				q.Set("sort", sort)
			}
			path := "/"
			if boardID > 0 {
				path = fmt.Sprintf("/board/%d", boardID)
			}
			if enc := q.Encode(); enc != "" {
				return path + "?" + enc
			}
			return path
		},
		"pageURL": func(boardID uint, sort string, page int) string {
			q := url.Values{}
			if sort != "" && sort != "latest" {
				q.Set("sort", sort)
			}
			if page > 1 {
				q.Set("page", strconv.Itoa(page))
			}
			path := "/"
			if boardID > 0 {
				path = fmt.Sprintf("/board/%d", boardID)
			}
			if enc := q.Encode(); enc != "" {
				return path + "?" + enc
			}
			return path
		},
	}
}

// Load 解析全部模板（进程内一次）
func Load() (*template.Template, error) {
	loadOnce.Do(func() {
		tpl, loadErr = template.New("root").Funcs(funcMap()).ParseFS(apptemplates.FS, "*.tmpl")
	})
	return tpl, loadErr
}

// Execute 渲染命名模板到 w
func Execute(w io.Writer, name string, data any) error {
	t, err := Load()
	if err != nil {
		return err
	}
	return t.ExecuteTemplate(w, name, data)
}