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

import (
	"context"
	"embed"
	"errors"
	"html/template"
	"io/fs"
	"log/slog"
	"net/http"
	"sync"
	"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."},
	{Slug: "finance", Title: "Finance", Theme: "finance", Emoji: "💰", Blurb: "Markets, money, and the business of the world. Read-only — these stories don't post to Matrix."},
	{Slug: "lego", Title: "LEGO", Theme: "lego", Emoji: "🧱", Blurb: "Sets, releases, and the wider brick-building world."},
	{Slug: "adventure", Title: "Adventure", Theme: "adventure", Emoji: "⚔️", Blurb: "Dispatches from the realm — deaths, first-clears, arrivals, and rivalries. Reporting from the field, this is Pete."},
}

// 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
	postingEnabled bool // false = web-only mode; hides Matrix-posting UI
	srv            *http.Server
	tpls           map[string]*template.Template // keyed by page name (e.g. "index", "channel")
	auth           *Authenticator                // nil when sign-in is disabled or unavailable
	tts            *ttsService                   // nil when server-side read-aloud is disabled
	adminSubs      map[string]bool               // OIDC subjects allowed to view /status
	pushHTTP       *http.Client                  // SSRF-guarded client for Web Push delivery; built lazily by pushClient()
	adv            config.AdventureConfig        // gogobee adventure-news seam
	advPost        PriorityPoster                // posts priority adventure beats to Matrix; nil = web-only

	// Daily-rotated salt for the privacy-preserving unique-visitor estimate.
	// Guarded by metricsMu; never persisted (see metrics.go).
	metricsMu sync.Mutex
	saltDay   int64
	salt      [16]byte
}

// 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, postingEnabled bool, adv config.AdventureConfig, advPost PriorityPoster) (*Server, error) {
	pages := []string{"index", "channel", "weather", "bookmarks", "for-you", "status", "story"}
	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})
	}
	adminSubs := make(map[string]bool, len(cfg.AdminSubs))
	for _, sub := range cfg.AdminSubs {
		if sub != "" {
			adminSubs[sub] = true
		}
	}
	s := &Server{cfg: cfg, sources: infos, postingEnabled: postingEnabled, tpls: tpls, adminSubs: adminSubs, adv: adv, advPost: advPost}

	// Optional OIDC sign-in (Authentik). Discovery is a network call; if the
	// provider is unreachable at boot we log and serve anonymously rather than
	// refusing to start the whole site.
	if cfg.Auth.Enabled {
		dctx, cancel := context.WithTimeout(context.Background(), 15*time.Second)
		auth, err := newAuthenticator(dctx, cfg.Auth)
		cancel()
		if err != nil {
			slog.Error("web: OIDC auth init failed; sign-in disabled", "err", err)
		} else {
			s.auth = auth
			slog.Info("web: OIDC sign-in enabled", "issuer", cfg.Auth.Issuer)
		}
	}

	// Optional server-side neural read-aloud (Piper). Signed-in only, so it is
	// only useful alongside auth; newTTS logs and disables itself on any misconfig.
	if s.auth != nil {
		tts, err := newTTS(cfg.TTS)
		if err != nil {
			return nil, err
		}
		s.tts = tts
	} else if cfg.TTS.Enabled {
		slog.Warn("web: TTS enabled but auth is off; read-aloud is signed-in only, so it stays disabled")
	}

	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 /manifest.webmanifest", s.handleManifest)
	mux.HandleFunc("GET /sw.js", s.handleServiceWorker)

	mux.HandleFunc("GET /{$}", s.handleIndex)
	mux.HandleFunc("GET /weather", s.handleWeatherDemo)
	mux.HandleFunc("GET /api/search", s.handleSearch)
	mux.HandleFunc("GET /api/article", s.handleArticle)
	mux.HandleFunc("GET /api/related", s.handleRelated)
	mux.HandleFunc("GET /feed.xml", func(w http.ResponseWriter, r *http.Request) { s.handleFeedXML(w, r, "") })
	mux.HandleFunc("GET /feed.json", func(w http.ResponseWriter, r *http.Request) { s.handleFeedJSON(w, r, "") })
	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 /"+ch.Slug+"/feed.xml", func(w http.ResponseWriter, r *http.Request) { s.handleFeedXML(w, r, ch.Slug) })
		mux.HandleFunc("GET /"+ch.Slug+"/feed.json", func(w http.ResponseWriter, r *http.Request) { s.handleFeedJSON(w, r, ch.Slug) })
	}
	// Public source-health page. The handler renders a trimmed reader view for
	// everyone and the full diagnostic view only for admins, so it lives outside
	// the auth block.
	mux.HandleFunc("GET /status", s.handleStatus)

	mux.HandleFunc("GET /healthz", func(w http.ResponseWriter, _ *http.Request) {
		w.WriteHeader(http.StatusOK)
		_, _ = w.Write([]byte("ok"))
	})

	// gogobee adventure-news ingest. Bearer-authed (not OIDC), so it lives
	// outside the sign-in block. Self-gates on adv.Enabled (404 when off).
	mux.HandleFunc("POST /api/ingest/adventure", s.handleAdventureIngest)

	// Per-dispatch permalink (the article_url every ingested story points at).
	// Public GET; self-gates on adv.Enabled. Distinct from GET /adventure (the
	// channel listing, registered in the channels loop above).
	mux.HandleFunc("GET /adventure/{guid}", s.handleAdventureStory)

	// Themed per-event emblem (card + og:image). A distinct path depth from
	// /adventure/{guid}, so the two patterns never overlap.
	mux.HandleFunc("GET /adventure/art/{type}", s.handleAdventureArt)

	if s.auth != nil {
		mux.HandleFunc("GET /auth/login", s.auth.handleLogin)
		mux.HandleFunc("GET /auth/callback", s.auth.handleCallback)
		mux.HandleFunc("GET /auth/logout", s.auth.handleLogout)
		mux.HandleFunc("GET /api/preferences", s.handlePrefs)
		mux.HandleFunc("PUT /api/preferences", s.handlePrefs)
		mux.HandleFunc("POST /api/read", s.handleRead)
		mux.HandleFunc("POST /api/bookmark", s.handleBookmark)
		mux.HandleFunc("GET /api/state", s.handleState)
		mux.HandleFunc("GET /bookmarks", s.handleBookmarks)
		mux.HandleFunc("GET /for-you", s.handleForYou)
		if s.cfg.Push.Enabled {
			mux.HandleFunc("POST /api/push/subscribe", s.handlePushSubscribe)
			mux.HandleFunc("POST /api/push/unsubscribe", s.handlePushUnsubscribe)
		}
		if s.tts != nil {
			mux.HandleFunc("POST /api/tts", s.handleTTS)
		}
	}

	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)
	}
}