package main

import (
	"embed"
	"errors"
	"flag"
	"io/fs"
	"log"
	"net/http"
	"os"
	"os/signal"
	"time"

	"github.com/kami/maven/internal/ipc"
	"github.com/kami/maven/internal/webauthn"
)

//go:embed static/*
var staticFiles embed.FS

func noCache(h http.Handler) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		w.Header().Set("Cache-Control", "no-cache, no-store, must-revalidate")
		h.ServeHTTP(w, r)
	})
}

func main() {
	addr := flag.String("addr", "127.0.0.1:9200", "HTTP listen address (loopback by default; pass e.g. \":9200\" or a LAN IP deliberately for wider exposure — POST /chat and /routines are state-changing)")
	voiceAddr := flag.String("voice", "127.0.0.1:9100", "voice server TCP addr (host:port)")
	// ntfyWS: the ntfy WebSocket subscribe URL the PWA connects to for in-app
	// nudge delivery, e.g. wss://ntfy.kvmx.ru/maven/ws?auth=<base64-token>. The
	// client subscribes directly (lowest overhead — mavweb isn't in the path);
	// we only serve it the URL so the deny-all auth token stays deployment
	// config, never baked into the static JS. Empty ⇒ /api/ntfy returns 204 and
	// the PWA skips subscription (voice-only, as before).
	ntfyWS := flag.String("ntfy", "", "ntfy WebSocket subscribe URL served to the PWA (e.g. wss://host/topic/ws?auth=...)")
	// coreSock: mavend's IPC socket. When set, /api/signal writes presence
	// facts through CoreAPI (page heartbeat from the PWA, desk_active from a PC
	// script). Empty ⇒ /api/signal returns 503 and presence stays unfed.
	coreSock := flag.String("core", "", "mavend IPC socket path for presence-signal ingest (empty = disabled)")
	pkOrigin := flag.String("webauthn-origin", "", "WebAuthn origin URL (e.g. https://maven.kvmx.ru)")
	pkRPID := flag.String("webauthn-rpid", "", "WebAuthn RP ID (e.g. maven.kvmx.ru)")
	requireStepUp := flag.Bool("require-stepup", false, "fail closed on step-up-gated actions (POST /tools, /routines, /models, /api/revert, /api/chat and /api/ptt) when WebAuthn step-up cannot be asserted; default false preserves the historical fail-open behaviour")
	pkFile := flag.String("passkey-file", "./passkeys.json", "path to WebAuthn credential store (JSON)")
	nexusURL := flag.String("nexus", "", "Nexus base URL for the /ecosystem panel (empty = not configured)")
	praxisURL := flag.String("praxis", "", "Praxis base URL for the /ecosystem panel (empty = not configured)")
	hexisURL := flag.String("hexis", "", "Hexis base URL for the /ecosystem panel (empty = not configured)")
	// Shared secret for POST /api/ambient, the notification-relay ingest that
	// reads the work calendar as a signal instead of holding a work credential
	// (see ambient.go). Enabling and authenticating are separate on purpose: an
	// expanded-empty secret cannot silently turn a live integration off.
	ambientEnabled := flag.Bool("ambient-enabled", false, "enable POST /api/ambient notification ingest (requires -ambient-token)")
	ambientToken := flag.String("ambient-token", "", "shared secret for POST /api/ambient notification ingest")
	flag.Parse()
	if err := validateAmbientConfig(*ambientEnabled, *ambientToken); err != nil {
		log.Fatal(err)
	}

	var core ipc.CoreAPI
	// swapConn — a second connection, for /models and nothing else. A model swap
	// is a multi-minute IPC call and ipc.Client serialises everything on one
	// mutex, so sharing the connection would freeze every other page for the
	// length of the load. See handleModels.
	var swapConn modelController
	// turnConn — a third connection, for POST /api/chat and nothing else, for
	// the same reason /models has one (V-638). A chat turn routes, phrases and
	// may act, bounded only by phraser.timeout at 60s, and every other handler
	// on this server queues behind it on the shared client's one mutex. Nil ⇒
	// chat shares the main connection, which is how it behaved before.
	var turnConn ipc.CoreAPI
	if *coreSock != "" {
		c, err := ipc.DialWait(*coreSock, 60*time.Second)
		if err != nil {
			log.Fatalf("dial core %s: %v", *coreSock, err)
		}
		defer c.Close()
		core = c
		if sc, err := ipc.Dial(*coreSock); err != nil {
			log.Printf("models: second core connection failed (%v) — /models will share the main one and a swap will block the other pages", err)
		} else {
			defer sc.Close()
			swapConn = sc
		}
		if tc, err := ipc.Dial(*coreSock); err != nil {
			log.Printf("chat: third core connection failed (%v) — /api/chat will share the main one and a turn will block the other pages", err)
		} else {
			defer tc.Close()
			turnConn = tc
		}
	}

	// stepUpSession stays nil unless the passkey endpoints are wired below — it
	// can only ever be asserted via AssertFinish, so gating POST /tools on it
	// without those endpoints would make tool enable/disable permanently 403.
	// Declared here because the gated routes close over it.
	var stepUpSession *webauthn.PasskeySession

	// The two handler shapes on this server, so the route table below reads as
	// a table rather than as twenty identical closures. Both close over `core`
	// and `stepUpSession`, which is what lets the gated routes be registered
	// before the passkey endpoints decide whether step-up exists at all.
	corePage := func(h func(http.ResponseWriter, *http.Request, ipc.CoreAPI)) http.HandlerFunc {
		return func(w http.ResponseWriter, r *http.Request) { h(w, r, core) }
	}
	gatedPage := func(h func(http.ResponseWriter, *http.Request, ipc.CoreAPI, *webauthn.PasskeySession, bool)) http.HandlerFunc {
		return func(w http.ResponseWriter, r *http.Request) { h(w, r, core, stepUpSession, *requireStepUp) }
	}

	mux := http.NewServeMux()

	sub, err := fs.Sub(staticFiles, "static")
	if err != nil {
		log.Fatalf("static fs: %v", err)
	}
	staticHandler := noCache(http.FileServer(http.FS(sub)))
	mux.Handle("/", http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		if r.URL.Path != "/" {
			staticHandler.ServeHTTP(w, r)
			return
		}
		handleVoice(w, r)
	}))

	mux.HandleFunc("/api/ping", func(w http.ResponseWriter, r *http.Request) {
		w.Write([]byte("pong"))
	})
	mux.HandleFunc("/api/ntfy", func(w http.ResponseWriter, r *http.Request) {
		if *ntfyWS == "" {
			w.WriteHeader(http.StatusNoContent) // not configured → PWA skips
			return
		}
		w.Header().Set("Content-Type", "text/plain")
		w.Write([]byte(*ntfyWS))
	})
	mux.HandleFunc("/api/signal", corePage(handleSignal))
	// Off unless explicitly enabled: a dark ingest has no route at all, while an
	// enabled ingest with no token was rejected before the server was built.
	if *ambientEnabled {
		mux.HandleFunc("/api/ambient", func(w http.ResponseWriter, r *http.Request) {
			handleAmbient(w, r, core, *ambientToken)
		})
		log.Printf("mavweb: ambient notification ingest enabled at POST /api/ambient")
	}

	// The data surfaces. Every one of them 503s without -core. /reminders also
	// accepts an ID-bound cancellation POST. It is deliberately not step-up
	// gated: like dismissing a proposed routine, it can only make Maven quieter.
	mux.HandleFunc("/dash", corePage(handleDash))
	mux.HandleFunc("/history", corePage(handleHistory))
	mux.HandleFunc("/trace", corePage(handleTrace))
	mux.HandleFunc("/notifications", corePage(handleNotifications))
	mux.HandleFunc("/reminders", corePage(handleReminders))
	mux.HandleFunc("/morning", corePage(handleMorning))
	mux.HandleFunc("/events", corePage(handleEvents))
	// /tasks — capture + review. POST is not step-up gated; see handleTasks for
	// why a task write is not in the same class as /tools or /routines.
	mux.HandleFunc("/tasks", corePage(handleTasks))
	// GET /chat only renders the page and echoes back the q/r query params the
	// POST redirect set — nothing to gate.
	mux.HandleFunc("/chat", corePage(handleChatPage))

	ecoURLsCfg := ecoURLs{nexus: *nexusURL, praxis: *praxisURL, hexis: *hexisURL}
	mux.HandleFunc("/ecosystem", func(w http.ResponseWriter, r *http.Request) {
		handleEcosystem(w, r, ecoURLsCfg, core)
	})

	// ----- passkey (WebAuthn) endpoints -----
	// Wired when both -core and a configured origin are present. The origin
	// must match the browser's view of mavweb (e.g. https://maven.kvmx.ru).
	// Passkey registration + assertion are the step-up mechanism for
	// AuthStepUp actions (tool enable). Without -webauthn-origin, these
	// endpoints return 503 and step-up is unavailable (FloorSession), and
	// /tools falls back to the transport-level auth it sits behind
	// (wg+nginx+auth), same as before step-up existed.
	if *pkOrigin != "" && *pkRPID != "" && core != nil {
		stepUpSession = webauthn.NewPasskeySession(5 * time.Minute)
		pk, err := newPasskeyHandle(webauthn.Config{
			Origin: *pkOrigin,
			RPID:   *pkRPID,
			RPName: "maven",
		}, core, *pkFile, stepUpSession)
		if err != nil {
			log.Fatalf("passkey store: %v", err)
		}
		mux.HandleFunc("/auth/passkey", pk.Page)
		mux.HandleFunc("/auth/webauthn/register/begin", pk.RegisterBegin)
		mux.HandleFunc("/auth/webauthn/register/finish", pk.RegisterFinish)
		mux.HandleFunc("/auth/webauthn/assert/begin", pk.AssertBegin)
		mux.HandleFunc("/auth/webauthn/assert/finish", pk.AssertFinish)
	} else {
		logUnguardedSurfaces(*requireStepUp)
	}

	// State-changing routes on this server, and their gate (Vikunja #317):
	//
	//   POST /tools      step-up  — defines argv that internal/tool executes
	//   POST /routines   step-up  — accepting schedules recurring firing
	//   POST /models     step-up  — replaces the model that routes and phrases
	//   POST /api/revert step-up  — voids the latest fact for a key
	//   POST /api/chat   step-up  — reaches the router, LLM and the act path
	//   POST /api/ptt    step-up  — audio into runTurn, so the same router,
	//                               LLM and act path as /api/chat
	//   POST /api/signal none     — appends a presence fact, no argv, no act
	//   POST /api/ambient shared secret — notification relay, constant-time
	//                               token compare, poster is a phone service
	//                               and not a browser, so step-up cannot apply
	//
	// "step-up" means stepUpOK: asserted passkey when WebAuthn is configured,
	// otherwise fail-open unless -require-stepup, which denies.
	//
	// /api/ptt used to be ungated, justified by mavend's voice port
	// being reachable only inside the deploy. That argument does not hold:
	// mavweb is the thing proxying into it from outside. Speaking "выключи
	// свет" is not a smaller act than typing it (Vikunja #317).
	//
	// The gate here is per-request, which costs the hands-free case a passkey
	// assertion per turn whenever WebAuthn is configured. A session-scoped
	// assertion covering a run of turns is the right shape and is its own task.
	//
	// /tools is the authed enable surface: maven proposes acts she can't run,
	// and this page is where a human reviews and enables them. Enabling is the
	// boundary-moving act (docs/design.md § Tool registration — drafting is
	// suggest, enabling is act), so it lives ONLY here, never on voice or chat.
	// /models is the same tier for a comparable reason: which model is loaded
	// decides how every utterance is routed and how every reply is worded.
	mux.HandleFunc("/tools", gatedPage(handleTools))
	mux.HandleFunc("/routines", gatedPage(handleRoutines))
	mux.HandleFunc("/api/chat", func(w http.ResponseWriter, r *http.Request) {
		c := turnConn
		if c == nil {
			c = core
		}
		handleChatAPI(w, r, c, stepUpSession, *requireStepUp)
	})
	mux.HandleFunc("/api/revert", gatedPage(handleRevert))
	mux.HandleFunc("/api/correct", gatedPage(handleCorrectAPI))
	mux.HandleFunc("/models", func(w http.ResponseWriter, r *http.Request) {
		handleModels(w, r, core, swapConn, stepUpSession, *requireStepUp)
	})
	mux.HandleFunc("/api/ptt", func(w http.ResponseWriter, r *http.Request) {
		handlePTT(w, r, *voiceAddr, stepUpSession, *requireStepUp)
	})

	srv := mavwebHTTPServer(*addr, mux)

	go func() {
		sig := make(chan os.Signal, 1)
		signal.Notify(sig, os.Interrupt)
		<-sig
		log.Println("shutting down...")
		srv.Close()
	}()

	log.Printf("mavweb listening on %s, voice → %s", *addr, *voiceAddr)
	if err := srv.ListenAndServe(); err != nil && !errors.Is(err, http.ErrServerClosed) {
		log.Fatal(err)
	}
}

func validateAmbientConfig(enabled bool, token string) error {
	if enabled && token == "" {
		return errors.New("mavweb: ambient ingest is enabled but -ambient-token is empty")
	}
	return nil
}

// logUnguardedSurfaces names, at startup, what step-up would have covered had
// WebAuthn been configured. One surface per line: these are read in a terminal
// at the moment someone is deciding whether the box is safe to expose.
func logUnguardedSurfaces(requireStepUp bool) {
	surfaces := []string{
		"POST /tools        defines arbitrary argv via name+cmd, which internal/tool then EXECUTES",
		"POST /routines     accepting schedules recurring firing",
		"POST /models       chooses the resident model that routes and words every turn",
		"POST /api/revert   voids the latest fact for a key",
		"POST /api/chat     reaches the router, the LLM and, through applyAction, the act path",
		"POST /api/ptt      the same, from audio",
	}
	if requireStepUp {
		log.Printf("SECURITY: step-up verification is DISABLED (-webauthn-origin/-webauthn-rpid unset) and -require-stepup is set. These surfaces will be DENIED (403):")
	} else {
		log.Printf("SECURITY WARNING: step-up verification is DISABLED (-webauthn-origin/-webauthn-rpid unset). These surfaces are UNGUARDED:")
	}
	for _, s := range surfaces {
		log.Printf("SECURITY:   %s", s)
	}
	if requireStepUp {
		log.Printf("SECURITY: set -webauthn-origin and -webauthn-rpid to enable passkey step-up.")
	} else {
		log.Printf("SECURITY: they rest on the transport-level auth in front of mavweb (wg+nginx+auth). Do NOT expose -addr on a public interface. Set -webauthn-origin and -webauthn-rpid to require passkey step-up, or pass -require-stepup to fail closed instead.")
	}
}

const (
	mavwebReadHeaderTimeout = 10 * time.Second
	mavwebReadTimeout       = 2 * time.Minute
	mavwebIdleTimeout       = 2 * time.Minute
	mavwebMaxHeaderBytes    = 32 << 10
)

func mavwebHTTPServer(addr string, handler http.Handler) *http.Server {
	return &http.Server{
		Addr:              addr,
		Handler:           withRequestID(handler),
		ReadHeaderTimeout: mavwebReadHeaderTimeout,
		ReadTimeout:       mavwebReadTimeout,
		IdleTimeout:       mavwebIdleTimeout,
		MaxHeaderBytes:    mavwebMaxHeaderBytes,
	}
}