package utils

import (
	"html/template"
	"net/http"

	"github.com/gin-gonic/gin/render"
)

// 模板函数
func templateFuncs() template.FuncMap {
	return template.FuncMap{
		"add": func(a, b int) int {
			return a + b
		},
		"sub": func(a, b int) int {
			return a - b
		},
		"html": func(s string) template.HTML {
			return template.HTML(s)
		},
	}
}

// 自定义 HTMLRender，存储一个 map：页面名 -> *template.Template
type TemplateRenderer struct {
	templates map[string]*template.Template
}

func (r *TemplateRenderer) Lookup(name string) *template.Template {
	return r.templates[name]
}

func (r *TemplateRenderer) Instance(name string, data any) render.Render {
	return &htmlRender{
		tmpl: r.Lookup(name),
		data: data,
		name: name,
	}
}

type htmlRender struct {
	tmpl *template.Template
	data any
	name string
}

func (r *htmlRender) Render(w http.ResponseWriter) error {
	r.WriteContentType(w)
	return r.tmpl.ExecuteTemplate(w, "base.html", r.data)
}

func (r *htmlRender) WriteContentType(w http.ResponseWriter) {
	w.Header().Set("Content-Type", "text/html; charset=utf-8")
}

// 初始化多模板
func LoadTemplates(theme string) *TemplateRenderer {
	r := &TemplateRenderer{
		templates: make(map[string]*template.Template),
	}

	templateDir := "templates/" + theme

	// 为每个页面创建独立的模板组合
	pages := []string{"index", "post", "page"}
	for _, pageName := range pages {
		// 组合 base.html 和具体页面模板
		allFiles := []string{
			templateDir + "/base.html",
			templateDir + "/" + pageName + ".html",
		}
		tmpl := template.Must(template.New("").Funcs(templateFuncs()).ParseFiles(allFiles...))
		r.templates[pageName] = tmpl
	}

	return r
}