// Package web serves Pete's read-only news interface.
package web

import (
	"context"
	"embed"
	"errors"
	"html/template"
	"io/fs"
	"log/slog"
	"net/http"
	"time"

	"pete/internal/config"
)

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

//go:embed static
var staticFS embed.FS

// Channel describes one section of the site.
type Channel struct {
	Slug  string // "gaming"
	Title string // "Gaming"
	Theme string // tailwind theme key: "gaming" | "tech" | "politics"
	Emoji string
	Blurb string
}

// channels in display order. Add a new entry here to add a section.
var channels = []Channel{
	{Slug: "gaming", Title: "Gaming", Theme: "gaming", Emoji: "🎮", Blurb: "Releases, platforms, and the people making the games."},
	{Slug: "tech", Title: "Tech", Theme: "tech", Emoji: "💻", Blurb: "Industry, products, and the wires that hold it all together."},
	{Slug: "politics", Title: "Politics", Theme: "politics", Emoji: "🏛️", Blurb: "Policy, power, and the news of the day."},
	{Slug: "eu", Title: "EU", Theme: "eu", Emoji: "🇪🇺", Blurb: "Portugal and the wider European beat. Read-only — these stories don't post to Matrix."},
	{Slug: "music", Title: "Music", Theme: "music", Emoji: "🎵", Blurb: "Records, scenes, and the artists shaping the sound."},
	{Slug: "anime", Title: "Anime", Theme: "anime", Emoji: "🌸", Blurb: "Series, studios, and the wider world of anime and manga."},
	{Slug: "foss", Title: "FOSS", Theme: "foss", Emoji: "🐧", Blurb: "Kernel, distros, and the wider free and open source software world."},
	{Slug: "kids", Title: "Kids", Theme: "kids", Emoji: "🧒", Blurb: "World news written for younger readers — short, clear, and curious."},
}

// SourceInfo is the trimmed view of a configured feed for the settings panel.
type SourceInfo struct {
	Name    string `json:"name"`
	Channel string `json:"channel"`
}

// Server is the HTTP server for Pete's web UI.
type Server struct {
	cfg     config.WebConfig
	sources []SourceInfo
	srv     *http.Server
	tpls    map[string]*template.Template // keyed by page name (e.g. "index", "channel")
}

// New builds the server. Templates are parsed once at startup. Each page
// gets its own template set sharing layout.html + _card.html, which avoids
// `main` define collisions between pages.
func New(cfg config.WebConfig, sources []config.SourceConfig) (*Server, error) {
	pages := []string{"index", "channel", "weather"}
	tpls := make(map[string]*template.Template, len(pages))
	for _, p := range pages {
		t, err := template.New("").Funcs(funcs).ParseFS(templateFS,
			"templates/layout.html",
			"templates/_card.html",
			"templates/"+p+".html",
		)
		if err != nil {
			return nil, err
		}
		tpls[p] = t
	}
	infos := make([]SourceInfo, 0, len(sources))
	for _, sc := range sources {
		if !sc.Enabled || sc.Name == "" {
			continue
		}
		infos = append(infos, SourceInfo{Name: sc.Name, Channel: sc.DirectRoute})
	}
	s := &Server{cfg: cfg, sources: infos, tpls: tpls}
	mux := http.NewServeMux()

	staticSub, err := fs.Sub(staticFS, "static")
	if err != nil {
		return nil, err
	}
	mux.Handle("GET /static/", http.StripPrefix("/static/", http.FileServer(http.FS(staticSub))))
	mux.HandleFunc("GET /img/{name}", s.handleImg)

	mux.HandleFunc("GET /{$}", s.handleIndex)
	mux.HandleFunc("GET /weather", s.handleWeatherDemo)
	mux.HandleFunc("GET /api/search", s.handleSearch)
	for _, ch := range channels {
		ch := ch
		mux.HandleFunc("GET /"+ch.Slug, func(w http.ResponseWriter, r *http.Request) {
			s.handleChannel(w, r, ch)
		})
	}
	mux.HandleFunc("GET /healthz", func(w http.ResponseWriter, _ *http.Request) {
		w.WriteHeader(http.StatusOK)
		_, _ = w.Write([]byte("ok"))
	})

	s.srv = &http.Server{
		Addr:              cfg.ListenAddr,
		Handler:           mux,
		ReadHeaderTimeout: 5 * time.Second,
	}
	return s, nil
}

// Start runs the HTTP server and blocks until ctx is canceled.
func (s *Server) Start(ctx context.Context) {
	go func() {
		<-ctx.Done()
		shutdownCtx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
		defer cancel()
		_ = s.srv.Shutdown(shutdownCtx)
	}()
	slog.Info("web server listening", "addr", s.cfg.ListenAddr)
	if err := s.srv.ListenAndServe(); err != nil && !errors.Is(err, http.ErrServerClosed) {
		slog.Error("web server crashed", "err", err)
	}
}