import { z } from "zod";

import { createAudioContext } from "../audio/engine";
import {
  errorMessage,
  getConfig,
  getProfile,
  getReports,
  getTools,
  post,
  reasoningSchema,
  searchSchema,
} from "../lib/api";
import { buildInstructions, profileContext, ragContext, speechInstructions, WEB_SEARCH } from "../lib/context";
import {
  defaultConfig,
  type ConnectionStatus,
  type DynamicTool,
  type Profile,
  type Reports,
  type ServerConfig,
  type ToolCall,
  type Transcript,
} from "../lib/contracts";
import type { Message } from "../lib/messages";
import {
  callerFromLocation,
  connectionTarget,
  GATE_OFF,
  loadSettings,
  saveSettings,
  type Caller,
  type Settings,
} from "../lib/settings";
import { RealtimeClient, SessionError } from "./client";

export const LIVE_STATES = new Set<ConnectionStatus>(["listening", "user-speaking", "processing", "ai-speaking"]);
export const ACTIVE_STATES = new Set<ConnectionStatus>([...LIVE_STATES, "connecting", "queued", "your-turn"]);
export interface AppState {
  loading: boolean;
  configReady: boolean;
  configError: string;
  contextLoading: boolean;
  config: ServerConfig;
  settings: Settings;
  profile: Profile | null;
  reports: Reports | null;
  tools: DynamicTool[];
  toolsLoading: boolean;
  toolsError: string;
  status: ConnectionStatus;
  error: string;
  notice: string;
  messages: Message[];
  muted: boolean;
  rag: string;
  queuePosition: number;
  joinDeadline: number;
  unlock: boolean;
  wakeWordEnabled: boolean;
}

/** Observable application state; React owns rendering, this object owns session lifetime. */
export class VoiceController {
  readonly caller: Caller;
  private state: AppState;
  private readonly listeners = new Set<() => void>();
  private readonly levelListeners = new Set<() => void>();
  private level = 0;
  private client: RealtimeClient | null = null;
  private subscriptions: (() => void)[] = [];
  private requests = new AbortController();
  private initialization: AbortController | null = null;
  private reasoningRequest: AbortController | null = null;
  private reasoningTurn = 0;
  private externalSpeaking = false;
  private idleTimer: ReturnType<typeof setInterval> | undefined;
  private lastActivity = Date.now();
  private lastMeter = 0;
  private sessionNumber = 0;
  private reasoned = new Set<string>();
  private autoStarted = false;

  constructor(caller = callerFromLocation()) {
    this.caller = caller;
    this.state = {
      loading: true,
      configReady: false,
      configError: "",
      contextLoading: false,
      config: defaultConfig,
      settings: loadSettings(),
      profile: null,
      reports: null,
      tools: [],
      toolsLoading: false,
      toolsError: "",
      status: "idle",
      error: "",
      notice: "",
      messages: [],
      muted: false,
      rag: "",
      queuePosition: 0,
      joinDeadline: 0,
      unlock: false,
      wakeWordEnabled: false,
    };
  }
  getSnapshot = () => this.state;
  getLevel = () => this.level;
  subscribeLevel = (listener: () => void) => {
    this.levelListeners.add(listener);
    return () => {
      this.levelListeners.delete(listener);
    };
  };
  private updateLevel(level: number) {
    if (this.level === level) {
      return;
    }
    this.level = level;
    this.levelListeners.forEach((listener) => {
      listener();
    });
  }
  subscribe = (listener: () => void) => {
    this.listeners.add(listener);
    return () => {
      this.listeners.delete(listener);
    };
  };
  private update(patch: Partial<AppState>) {
    this.state = { ...this.state, ...patch };
    this.listeners.forEach((listener) => {
      listener();
    });
  }

  async initialize(parent?: AbortSignal) {
    this.initialization?.abort();
    const initialization = new AbortController();
    this.initialization = initialization;
    const { signal } = initialization;
    const cancel = () => {
      initialization.abort();
    };
    if (parent?.aborted) {
      cancel();
      return;
    }
    parent?.addEventListener("abort", cancel, { once: true });
    this.update({ loading: true, configReady: false, configError: "", contextLoading: !!this.caller.phoneNumber });
    const configuration = getConfig(signal);
    const profile = getProfile(this.caller.phoneNumber, signal)
      .then((profile) => {
        if (!signal.aborted) {
          this.update({ profile, contextLoading: false });
          this.pushSettings();
        }
      })
      .catch(() => undefined);
    const reports = getReports(this.caller.phoneNumber, signal)
      .then((reports) => {
        if (!signal.aborted) {
          this.update({ reports });
        }
      })
      .catch(() => undefined);
    const configure = async () => {
      try {
        const config = await configuration;
        if (signal.aborted) {
          return;
        }
        this.update({ config, configReady: true, loading: false });
        if (config.apipilot) {
          await profile;
          if (!signal.aborted) {
            await this.refreshTools(signal, !!this.state.profile);
          }
        }
      } catch (error) {
        if (!signal.aborted) {
          this.update({ loading: false, configError: `No se pudo cargar la configuración. ${errorMessage(error)}` });
        }
      }
    };
    try {
      await Promise.all([configure(), profile, reports]);
    } finally {
      parent?.removeEventListener("abort", cancel);
    }
  }
  dispose() {
    this.initialization?.abort();
    void this.stop();
  }
  async refreshTools(signal: AbortSignal, refresh = false) {
    this.update({ toolsLoading: true, toolsError: "" });
    try {
      const tools = await getTools(signal, refresh);
      if (!signal.aborted) {
        this.update({ tools, toolsLoading: false });
        this.pushSettings();
      }
    } catch (error) {
      if (!signal.aborted) {
        this.update({ toolsError: errorMessage(error), toolsLoading: false });
      }
    }
  }
  private instructions() {
    return buildInstructions(
      this.state.config,
      this.state.settings,
      this.state.profile,
      this.state.rag,
      this.state.tools,
    );
  }
  private tools() {
    return this.state.settings.webSearch && (this.state.config.search || this.state.settings.searchKey)
      ? [WEB_SEARCH]
      : [];
  }
  private gate() {
    return { enabled: this.state.settings.noiseGate > GATE_OFF, thresholdDb: this.state.settings.noiseGate };
  }
  private pushSettings() {
    this.client?.updateSession(
      speechInstructions(this.instructions(), this.state.config),
      this.state.settings.voice,
      this.tools(),
    );
  }
  changeSettings(patch: Partial<Settings>) {
    const changed = Object.fromEntries(
      Object.entries(patch).filter(([key, value]) => this.state.settings[key as keyof Settings] !== value),
    ) as Partial<Settings>;
    if (!Object.keys(changed).length) {
      return;
    }
    const settings = { ...this.state.settings, ...changed };
    this.update({ settings });
    saveSettings(changed);
    if (changed.noiseGate !== undefined) {
      this.client?.setGate(this.gate());
    }
    if (
      changed.voice !== undefined ||
      changed.instructions !== undefined ||
      changed.webSearch !== undefined ||
      changed.searchKey !== undefined
    ) {
      this.pushSettings();
    }
  }
  setRag(rag: string) {
    this.update({ rag: rag.trim() });
    this.pushSettings();
  }
  dismissError() {
    this.update({ error: "" });
  }
  dismissUnlock() {
    this.update({ unlock: false });
  }
  setWakeWordEnabled(wakeWordEnabled: boolean) {
    this.update({ wakeWordEnabled });
  }
  offerAutoStart() {
    if (this.autoStarted || this.client || !this.state.configReady || this.state.contextLoading) {
      return;
    }
    this.autoStarted = true;
    const mode = this.state.config.startSessionMode.trim().toUpperCase();
    if (mode === "TALK") {
      this.update({ unlock: true });
    } else if (mode === "TALKFIRST") {
      void this.start(true);
    }
  }
  async start(automatic = false, preparedContext?: AudioContext, greeting?: string) {
    if (this.client || !this.state.configReady || this.state.contextLoading) {
      if (preparedContext) {
        void preparedContext.close().catch(() => undefined);
      }
      return;
    }
    this.update({
      unlock: false,
      error: "",
      notice: "",
      status: "connecting",
      muted: false,
      joinDeadline: 0,
    });
    let context: AudioContext | undefined;
    try {
      if (!navigator.mediaDevices?.getUserMedia || typeof AudioContext === "undefined") {
        throw new Error("El micrófono necesita HTTPS o localhost y un navegador compatible.");
      }
      const target = connectionTarget(this.state.config, this.state.settings, this.caller);
      context = preparedContext ?? createAudioContext();
      if (automatic && context.state !== "running") {
        await context.close();
        this.update({ status: "idle", unlock: true });
        return;
      }
      this.requests = new AbortController();
      this.reasoned.clear();
      this.sessionNumber++;
      const client = new RealtimeClient({
        ...target,
        context,
        voice: this.state.settings.voice,
        instructions: speechInstructions(this.instructions(), this.state.config),
        tools: this.tools(),
        gate: this.gate(),
        greeting:
          greeting ??
          (["TALK", "TALKFIRST"].includes(this.state.config.startSessionMode.toUpperCase())
            ? "hola vocero"
            : undefined),
      });
      this.client = client;
      this.subscriptions = [
        client.on("status", (status) => {
          if (client !== this.client) {
            return;
          }
          if (status === "closed") {
            void this.stop(this.state.error ? "error" : "closed");
            return;
          }
          if (status === "listening" || status === "user-speaking" || status === "ai-speaking") {
            this.lastActivity = Date.now();
          }
          if (status === "user-speaking") {
            this.cancelReasoning();
            window.speechSynthesis?.cancel();
            this.update({
              messages: this.state.messages.map((message) =>
                message.role === "assistant" && message.partial
                  ? { ...message, partial: false, interrupted: true }
                  : message,
              ),
            });
          }
          if (
            !["listening", "processing", "ai-speaking"].includes(status) ||
            (!this.reasoningRequest && !this.externalSpeaking)
          ) {
            this.update({ status });
          }
        }),
        client.on("transcript", (transcript) => {
          this.lastActivity = Date.now();
          this.transcript(transcript);
          if (transcript.role === "user" && !transcript.partial && !this.reasoned.has(transcript.id)) {
            this.reasoned.add(transcript.id);
            void this.reason(transcript, client);
          }
        }),
        client.on("finished", (response) => {
          if (response.transcript) {
            this.transcript(
              { id: response.responseId, role: "assistant", text: response.transcript, partial: false },
              response.status !== "completed",
            );
          }
        }),
        client.on("level", (level) => {
          if (!this.state.muted && level > 0.0025) {
            this.lastActivity = Date.now();
          }
          if (Date.now() - this.lastMeter > 150) {
            this.lastMeter = Date.now();
            this.updateLevel(level);
          }
        }),
        client.on("queue", ({ position }) => {
          this.update({ queuePosition: position });
        }),
        client.on("readyToJoin", ({ expiresSec }) => {
          this.update({ joinDeadline: Date.now() + expiresSec * 1000 });
        }),
        client.on("grant", () => {
          this.update({ joinDeadline: 0 });
        }),
        client.on("error", (error) => {
          this.reportError(error);
        }),
        client.on("serverError", (error) => {
          this.update({ error: error.message });
        }),
        client.on("tool", (call) => {
          void this.runTool(call, client);
        }),
      ];
      this.lastActivity = Date.now();
      this.idleTimer = setInterval(() => {
        if (
          this.state.status === "listening" &&
          !this.reasoningRequest &&
          !this.externalSpeaking &&
          Date.now() - this.lastActivity >= 30000
        ) {
          void this.stop();
          this.update({ notice: "Sesión finalizada por inactividad. Toca para volver a conversar." });
        }
      }, 1000);
      try {
        await client.connect();
      } catch (error) {
        // A closed event may already have cleared the client; explicit cancellation is silent.
        if (!(error instanceof SessionError && error.code === "aborted") && (!this.client || this.client === client)) {
          this.reportError(error);
          if (automatic) {
            this.update({ unlock: true });
          }
        }
      }
    } catch (error) {
      if (context) {
        void context.close().catch(() => undefined);
      }
      this.reportError(error);
    }
  }
  private reportError(error: unknown) {
    this.update({
      error: errorMessage(error),
      status: "error",
    });
  }
  private transcript(transcript: Transcript, interrupted = false) {
    if (!transcript.text.trim()) {
      return;
    }
    const id = `${String(this.sessionNumber)}:${transcript.role}:${transcript.id}`;
    const existing = this.state.messages.find((message) => message.id === id);
    const message: Message = {
      ...existing,
      id,
      role: transcript.role,
      text: transcript.text,
      partial: transcript.partial,
      timestamp: existing?.timestamp ?? new Date().toISOString(),
      interrupted: interrupted || existing?.interrupted,
    };
    this.update({
      messages: existing
        ? this.state.messages.map((item) => (item.id === id ? message : item))
        : [...this.state.messages, message],
    });
  }
  private cancelReasoning() {
    this.reasoningTurn++;
    this.reasoningRequest?.abort();
    this.reasoningRequest = null;
    this.externalSpeaking = false;
  }
  private async reason(transcript: Transcript, client: RealtimeClient) {
    const { config, profile, rag } = this.state;
    if (config.reasoningType === "PROXY" || !transcript.text.trim()) {
      return;
    }
    this.cancelReasoning();
    const turn = this.reasoningTurn;
    const request = new AbortController();
    this.reasoningRequest = request;
    this.update({ status: "processing" });
    const current = () => this.client === client && turn === this.reasoningTurn && !request.signal.aborted;
    window.speechSynthesis?.cancel();
    try {
      const result = await post(
        "/api/reasoning",
        reasoningSchema,
        {
          transcript: transcript.text.trim(),
          instructions: this.instructions(),
          language: "es-ES",
          user_context: [profileContext(profile), ragContext(rag)].filter(Boolean).join("\n\n"),
          phoneNumber: this.caller.phoneNumber || null,
          episode_id: this.caller.episodeId || null,
        },
        request.signal,
      );
      if (!current()) {
        return;
      }
      const answer = result.answer.trim();
      if (!answer) {
        throw new Error("El servicio de razonamiento no devolvió una respuesta.");
      }
      client.renderExternalAnswer(answer);
      this.transcript({ role: "assistant", id: `reasoning:${transcript.id}`, text: answer, partial: false });
      if ("speechSynthesis" in window) {
        this.externalSpeaking = true;
        const utterance = new SpeechSynthesisUtterance(answer);
        utterance.lang = "es-ES";
        const voice = window.speechSynthesis.getVoices().find((voice) => voice.lang.startsWith("es"));
        if (voice) {
          utterance.voice = voice;
        }
        utterance.onstart = () => {
          if (current()) {
            this.update({ status: "ai-speaking" });
          }
        };
        utterance.onend = utterance.onerror = () => {
          if (current()) {
            this.externalSpeaking = false;
            this.lastActivity = Date.now();
            this.update({ status: "listening" });
          }
        };
        window.speechSynthesis.cancel();
        window.speechSynthesis.speak(utterance);
      }
    } catch (error) {
      if (current()) {
        this.externalSpeaking = false;
        this.update({ error: errorMessage(error) });
      }
    } finally {
      if (turn === this.reasoningTurn) {
        this.reasoningRequest = null;
        if (!this.externalSpeaking && current()) {
          this.lastActivity = Date.now();
          this.update({ status: "listening" });
        }
      }
    }
  }
  private async runTool(call: ToolCall, client: RealtimeClient) {
    const id = `${String(this.sessionNumber)}:tool:${call.callId}`;
    let args = call.arguments;
    let output: string;
    try {
      const parsed: unknown = JSON.parse(call.arguments || "{}");
      args = JSON.stringify(parsed, null, 2);
      if (call.name !== "web_search") {
        throw new Error(`Herramienta desconocida: ${call.name}`);
      }
      const query = z.object({ query: z.string().trim().min(1) }).parse(parsed).query;
      const result = await post(
        "/api/search",
        searchSchema,
        {
          query,
          ...(!this.state.config.search && this.state.settings.searchKey ? { key: this.state.settings.searchKey } : {}),
        },
        this.requests.signal,
      );
      output = [
        `Google search result from ${new Date().toISOString().slice(0, 10)}:`,
        result.answer ? `Answer: ${result.answer}` : "",
        ...result.results.map((item) => `- ${item.title}: ${item.snippet} (${item.url})`),
      ]
        .filter(Boolean)
        .join("\n");
      if (!result.answer && !result.results.length) {
        output += "\nNo results found.";
      }
    } catch (error) {
      output = `Tool error: ${errorMessage(error)}`;
    }
    if (client !== this.client) {
      return;
    }
    this.update({
      messages: [
        ...this.state.messages,
        {
          id,
          role: "tool",
          text: output,
          toolName: call.name,
          toolArguments: args,
          partial: false,
          timestamp: new Date().toISOString(),
        },
      ],
    });
    client.sendToolOutput(call.callId, output);
  }
  join() {
    this.client?.join();
    this.update({ joinDeadline: 0 });
  }
  toggleMuted() {
    const muted = !this.state.muted;
    this.client?.setMuted(muted);
    this.update({ muted });
  }
  async restart() {
    // Resume before awaiting teardown so browsers retain the click's audio permission.
    const context = createAudioContext();
    await this.stop();
    await this.start(false, context);
  }
  async stop(status: ConnectionStatus = "closed") {
    const client = this.client;
    this.client = null;
    this.subscriptions.forEach((unsubscribe) => {
      unsubscribe();
    });
    this.subscriptions = [];
    clearInterval(this.idleTimer);
    this.requests.abort();
    this.cancelReasoning();
    window.speechSynthesis?.cancel();
    this.updateLevel(0);
    this.update({
      status,
      wakeWordEnabled: false,
      muted: false,
      joinDeadline: 0,
      unlock: false,
      messages: this.state.messages.map((message) =>
        message.partial ? { ...message, partial: false, interrupted: message.role === "assistant" } : message,
      ),
    });
    await client?.close();
  }
}