package templates

import (
	"bytes"
	"embed"
	"encoding/json"
	"html/template"
	"time"
)

//go:embed *.html
var templateFS embed.FS

var funcMap = template.FuncMap{
	"safeHTML": func(s string) template.HTML { return template.HTML(s) },
	"json":     func(v any) string { b, _ := json.Marshal(v); return string(b) },
	"or": func(a, b any) any {
		if a != nil && a != "" {
			return a
		}
		return b
	},
}

var fontURLs = map[string]string{
	"system":        "",
	"inter":         "https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600;700&display=swap",
	"georgia":       "",
	"merriweather":  "https://fonts.googleapis.com/css2?family=Merriweather:wght@400;700&display=swap",
	"source-serif":  "https://fonts.googleapis.com/css2?family=Source+Serif+4:wght@400;600;700&display=swap",
	"jetbrains-mono": "https://fonts.googleapis.com/css2?family=JetBrains+Mono:wght@400;500;700&display=swap",
}

var fontFamilies = map[string]string{
	"system":        "system-ui, -apple-system, sans-serif",
	"inter":         "'Inter', system-ui, sans-serif",
	"georgia":       "Georgia, 'Times New Roman', serif",
	"merriweather":  "'Merriweather', Georgia, serif",
	"source-serif":  "'Source Serif 4', Georgia, serif",
	"jetbrains-mono": "'JetBrains Mono', 'Fira Code', monospace",
}

func GetFontURL(fontKey string) string {
	if url, ok := fontURLs[fontKey]; ok {
		return url
	}
	return ""
}

func GetFontFamily(fontKey string) string {
	if family, ok := fontFamilies[fontKey]; ok {
		return family
	}
	return fontFamilies["system"]
}

var homeTemplate, blogTemplate, postTemplate *template.Template

func init() {
	homeTemplate = template.Must(template.New("").Funcs(funcMap).ParseFS(templateFS, "base.html", "home.html"))
	blogTemplate = template.Must(template.New("").Funcs(funcMap).ParseFS(templateFS, "base.html", "blog.html"))
	postTemplate = template.Must(template.New("").Funcs(funcMap).ParseFS(templateFS, "base.html", "post.html"))
}

type PageData struct {
	Title          string
	Description    string
	CanonicalURL   string
	OGType         string
	OGImage        string
	NoIndex        bool
	SiteName       string
	Year           int
	FontURL        string
	FontFamily     string
	StructuredData template.JS
	Settings       map[string]any
	ShowBadge      bool
}

type HomeData struct {
	PageData
	Posts   []PostSummary
	HasMore bool
}

type BlogData struct {
	PageData
	Posts    []PostSummary
	PrevPage string
	NextPage string
}

type PostData struct {
	PageData
	Post              PostDetail
	ContentHTML       template.HTML
	InteractionConfig map[string]any
}

type PostSummary struct {
	Slug        string
	Title       string
	Description string
	Date        time.Time
}

type PostDetail struct {
	Slug        string
	Title       string
	Description string
	CoverImage  string
	Date        time.Time
	Tags        []string
}

func RenderHome(data HomeData) ([]byte, error) {
	var buf bytes.Buffer
	if err := homeTemplate.ExecuteTemplate(&buf, "base.html", data); err != nil {
		return nil, err
	}
	return buf.Bytes(), nil
}

func RenderBlog(data BlogData) ([]byte, error) {
	var buf bytes.Buffer
	if err := blogTemplate.ExecuteTemplate(&buf, "base.html", data); err != nil {
		return nil, err
	}
	return buf.Bytes(), nil
}

func RenderPost(data PostData) ([]byte, error) {
	var buf bytes.Buffer
	if err := postTemplate.ExecuteTemplate(&buf, "base.html", data); err != nil {
		return nil, err
	}
	return buf.Bytes(), nil
}