import crypto from "node:crypto";
import fs from "node:fs";
import fsp from "node:fs/promises";
import os from "node:os";
import path from "node:path";

import { resolveUserPath } from "./utils.js";
import type { CallMode, VoiceCallConfig } from "./config.js";
import type { VoiceCallProvider } from "./providers/base.js";
import {
  type CallId,
  type CallRecord,
  CallRecordSchema,
  type CallState,
  type NormalizedEvent,
  type OutboundCallOptions,
  TerminalStates,
  type TranscriptEntry,
} from "./types.js";
import { escapeXml, mapVoiceToPolly } from "./voice-mapping.js";

/**
 * Manages voice calls: state machine, persistence, and provider coordination.
 */
export class CallManager {
  private activeCalls = new Map<CallId, CallRecord>();
  private providerCallIdMap = new Map<string, CallId>(); // providerCallId -> internal callId
  private processedEventIds = new Set<string>();
  private provider: VoiceCallProvider | null = null;
  private config: VoiceCallConfig;
  private storePath: string;
  private webhookUrl: string | null = null;
  private transcriptWaiters = new Map<
    CallId,
    {
      resolve: (text: string) => void;
      reject: (err: Error) => void;
      timeout: NodeJS.Timeout;
    }
  >();
  /** Max duration timers to auto-hangup calls after configured timeout */
  private maxDurationTimers = new Map<CallId, NodeJS.Timeout>();

  constructor(config: VoiceCallConfig, storePath?: string) {
    this.config = config;
    // Resolve store path with tilde expansion (like other config values)
    const rawPath =
      storePath ||
      config.store ||
      path.join(os.homedir(), "clawd", "voice-calls");
    this.storePath = resolveUserPath(rawPath);
  }

  /**
   * Initialize the call manager with a provider.
   */
  initialize(provider: VoiceCallProvider, webhookUrl: string): void {
    this.provider = provider;
    this.webhookUrl = webhookUrl;

    // Ensure store directory exists
    fs.mkdirSync(this.storePath, { recursive: true });

    // Load any persisted active calls
    this.loadActiveCalls();
  }

  /**
   * Get the current provider.
   */
  getProvider(): VoiceCallProvider | null {
    return this.provider;
  }

  /**
   * Initiate an outbound call.
   * @param to - The phone number to call
   * @param sessionKey - Optional session key for context
   * @param options - Optional call options (message, mode)
   */
  async initiateCall(
    to: string,
    sessionKey?: string,
    options?: OutboundCallOptions | string,
  ): Promise<{ callId: CallId; success: boolean; error?: string }> {
    // Support legacy string argument for initialMessage
    const opts: OutboundCallOptions =
      typeof options === "string" ? { message: options } : (options ?? {});
    const initialMessage = opts.message;
    const mode = opts.mode ?? this.config.outbound.defaultMode;
    if (!this.provider) {
      return { callId: "", success: false, error: "Provider not initialized" };
    }

    if (!this.webhookUrl) {
      return {
        callId: "",
        success: false,
        error: "Webhook URL not configured",
      };
    }

    // Check concurrent call limit
    const activeCalls = this.getActiveCalls();
    if (activeCalls.length >= this.config.maxConcurrentCalls) {
      return {
        callId: "",
        success: false,
        error: `Maximum concurrent calls (${this.config.maxConcurrentCalls}) reached`,
      };
    }

    const callId = crypto.randomUUID();
    const from =
      this.config.fromNumber ||
      (this.provider?.name === "mock" ? "+15550000000" : undefined);
    if (!from) {
      return { callId: "", success: false, error: "fromNumber not configured" };
    }

    // Create call record with mode in metadata
    const callRecord: CallRecord = {
      callId,
      provider: this.provider.name,
      direction: "outbound",
      state: "initiated",
      from,
      to,
      sessionKey,
      startedAt: Date.now(),
      transcript: [],
      processedEventIds: [],
      metadata: {
        ...(initialMessage && { initialMessage }),
        mode,
      },
    };

    this.activeCalls.set(callId, callRecord);
    this.persistCallRecord(callRecord);

    try {
      // For notify mode with a message, use inline TwiML with <Say>
      let inlineTwiml: string | undefined;
      if (mode === "notify" && initialMessage) {
        const pollyVoice = mapVoiceToPolly(this.config.tts.voice);
        inlineTwiml = this.generateNotifyTwiml(initialMessage, pollyVoice);
        console.log(
          `[voice-call] Using inline TwiML for notify mode (voice: ${pollyVoice})`,
        );
      }

      const result = await this.provider.initiateCall({
        callId,
        from,
        to,
        webhookUrl: this.webhookUrl,
        inlineTwiml,
      });

      callRecord.providerCallId = result.providerCallId;
      this.providerCallIdMap.set(result.providerCallId, callId); // Map providerCallId to internal callId
      this.persistCallRecord(callRecord);

      return { callId, success: true };
    } catch (err) {
      callRecord.state = "failed";
      callRecord.endedAt = Date.now();
      callRecord.endReason = "failed";
      this.persistCallRecord(callRecord);
      this.activeCalls.delete(callId);
      if (callRecord.providerCallId) {
        this.providerCallIdMap.delete(callRecord.providerCallId);
      }

      return {
        callId,
        success: false,
        error: err instanceof Error ? err.message : String(err),
      };
    }
  }

  /**
   * Speak to user in an active call.
   */
  async speak(
    callId: CallId,
    text: string,
  ): Promise<{ success: boolean; error?: string }> {
    const call = this.activeCalls.get(callId);
    if (!call) {
      return { success: false, error: "Call not found" };
    }

    if (!this.provider || !call.providerCallId) {
      return { success: false, error: "Call not connected" };
    }

    if (TerminalStates.has(call.state)) {
      return { success: false, error: "Call has ended" };
    }

    try {
      // Update state
      call.state = "speaking";
      this.persistCallRecord(call);

      // Add to transcript
      this.addTranscriptEntry(call, "bot", text);

      // Play TTS
      await this.provider.playTts({
        callId,
        providerCallId: call.providerCallId,
        text,
        voice: this.config.tts.voice,
      });

      return { success: true };
    } catch (err) {
      return {
        success: false,
        error: err instanceof Error ? err.message : String(err),
      };
    }
  }

  /**
   * Speak the initial message for a call (called when media stream connects).
   * This is used to auto-play the message passed to initiateCall.
   * In notify mode, auto-hangup after the message is delivered.
   */
  async speakInitialMessage(providerCallId: string): Promise<void> {
    const call = this.getCallByProviderCallId(providerCallId);
    if (!call) {
      console.warn(
        `[voice-call] speakInitialMessage: no call found for ${providerCallId}`,
      );
      return;
    }

    const initialMessage = call.metadata?.initialMessage as string | undefined;
    const mode = (call.metadata?.mode as CallMode) ?? "conversation";

    if (!initialMessage) {
      console.log(
        `[voice-call] speakInitialMessage: no initial message for ${call.callId}`,
      );
      return;
    }

    // Clear the initial message so we don't speak it again
    if (call.metadata) {
      delete call.metadata.initialMessage;
      this.persistCallRecord(call);
    }

    console.log(
      `[voice-call] Speaking initial message for call ${call.callId} (mode: ${mode})`,
    );
    const result = await this.speak(call.callId, initialMessage);
    if (!result.success) {
      console.warn(
        `[voice-call] Failed to speak initial message: ${result.error}`,
      );
      return;
    }

    // In notify mode, auto-hangup after delay
    if (mode === "notify") {
      const delaySec = this.config.outbound.notifyHangupDelaySec;
      console.log(
        `[voice-call] Notify mode: auto-hangup in ${delaySec}s for call ${call.callId}`,
      );
      setTimeout(async () => {
        const currentCall = this.getCall(call.callId);
        if (currentCall && !TerminalStates.has(currentCall.state)) {
          console.log(
            `[voice-call] Notify mode: hanging up call ${call.callId}`,
          );
          await this.endCall(call.callId);
        }
      }, delaySec * 1000);
    }
  }

  /**
   * Start max duration timer for a call.
   * Auto-hangup when maxDurationSeconds is reached.
   */
  private startMaxDurationTimer(callId: CallId): void {
    // Clear any existing timer
    this.clearMaxDurationTimer(callId);

    const maxDurationMs = this.config.maxDurationSeconds * 1000;
    console.log(
      `[voice-call] Starting max duration timer (${this.config.maxDurationSeconds}s) for call ${callId}`,
    );

    const timer = setTimeout(async () => {
      this.maxDurationTimers.delete(callId);
      const call = this.getCall(callId);
      if (call && !TerminalStates.has(call.state)) {
        console.log(
          `[voice-call] Max duration reached (${this.config.maxDurationSeconds}s), ending call ${callId}`,
        );
        call.endReason = "timeout";
        this.persistCallRecord(call);
        await this.endCall(callId);
      }
    }, maxDurationMs);

    this.maxDurationTimers.set(callId, timer);
  }

  /**
   * Clear max duration timer for a call.
   */
  private clearMaxDurationTimer(callId: CallId): void {
    const timer = this.maxDurationTimers.get(callId);
    if (timer) {
      clearTimeout(timer);
      this.maxDurationTimers.delete(callId);
    }
  }

  private clearTranscriptWaiter(callId: CallId): void {
    const waiter = this.transcriptWaiters.get(callId);
    if (!waiter) return;
    clearTimeout(waiter.timeout);
    this.transcriptWaiters.delete(callId);
  }

  private rejectTranscriptWaiter(callId: CallId, reason: string): void {
    const waiter = this.transcriptWaiters.get(callId);
    if (!waiter) return;
    this.clearTranscriptWaiter(callId);
    waiter.reject(new Error(reason));
  }

  private resolveTranscriptWaiter(callId: CallId, transcript: string): void {
    const waiter = this.transcriptWaiters.get(callId);
    if (!waiter) return;
    this.clearTranscriptWaiter(callId);
    waiter.resolve(transcript);
  }

  private waitForFinalTranscript(callId: CallId): Promise<string> {
    // Only allow one in-flight waiter per call.
    this.rejectTranscriptWaiter(callId, "Transcript waiter replaced");

    const timeoutMs = this.config.transcriptTimeoutMs;
    return new Promise((resolve, reject) => {
      const timeout = setTimeout(() => {
        this.transcriptWaiters.delete(callId);
        reject(
          new Error(`Timed out waiting for transcript after ${timeoutMs}ms`),
        );
      }, timeoutMs);

      this.transcriptWaiters.set(callId, { resolve, reject, timeout });
    });
  }

  /**
   * Continue call: speak prompt, then wait for user's final transcript.
   */
  async continueCall(
    callId: CallId,
    prompt: string,
  ): Promise<{ success: boolean; transcript?: string; error?: string }> {
    const call = this.activeCalls.get(callId);
    if (!call) {
      return { success: false, error: "Call not found" };
    }

    if (!this.provider || !call.providerCallId) {
      return { success: false, error: "Call not connected" };
    }

    if (TerminalStates.has(call.state)) {
      return { success: false, error: "Call has ended" };
    }

    try {
      await this.speak(callId, prompt);

      call.state = "listening";
      this.persistCallRecord(call);

      await this.provider.startListening({
        callId,
        providerCallId: call.providerCallId,
      });

      const transcript = await this.waitForFinalTranscript(callId);

      // Best-effort: stop listening after final transcript.
      await this.provider.stopListening({
        callId,
        providerCallId: call.providerCallId,
      });

      return { success: true, transcript };
    } catch (err) {
      return {
        success: false,
        error: err instanceof Error ? err.message : String(err),
      };
    } finally {
      this.clearTranscriptWaiter(callId);
    }
  }

  /**
   * End an active call.
   */
  async endCall(callId: CallId): Promise<{ success: boolean; error?: string }> {
    const call = this.activeCalls.get(callId);
    if (!call) {
      return { success: false, error: "Call not found" };
    }

    if (!this.provider || !call.providerCallId) {
      return { success: false, error: "Call not connected" };
    }

    if (TerminalStates.has(call.state)) {
      return { success: true }; // Already ended
    }

    try {
      await this.provider.hangupCall({
        callId,
        providerCallId: call.providerCallId,
        reason: "hangup-bot",
      });

      call.state = "hangup-bot";
      call.endedAt = Date.now();
      call.endReason = "hangup-bot";
      this.persistCallRecord(call);
      this.clearMaxDurationTimer(callId);
      this.rejectTranscriptWaiter(callId, "Call ended: hangup-bot");
      this.activeCalls.delete(callId);
      if (call.providerCallId) {
        this.providerCallIdMap.delete(call.providerCallId);
      }

      return { success: true };
    } catch (err) {
      return {
        success: false,
        error: err instanceof Error ? err.message : String(err),
      };
    }
  }

  /**
   * Check if an inbound call should be accepted based on policy.
   */
  private shouldAcceptInbound(from: string | undefined): boolean {
    const { inboundPolicy: policy, allowFrom } = this.config;

    switch (policy) {
      case "disabled":
        console.log("[voice-call] Inbound call rejected: policy is disabled");
        return false;

      case "open":
        console.log("[voice-call] Inbound call accepted: policy is open");
        return true;

      case "allowlist":
      case "pairing": {
        const normalized = from?.replace(/\D/g, "") || "";
        const allowed = (allowFrom || []).some((num) => {
          const normalizedAllow = num.replace(/\D/g, "");
          return (
            normalized.endsWith(normalizedAllow) ||
            normalizedAllow.endsWith(normalized)
          );
        });
        const status = allowed ? "accepted" : "rejected";
        console.log(
          `[voice-call] Inbound call ${status}: ${from} ${allowed ? "is in" : "not in"} allowlist`,
        );
        return allowed;
      }

      default:
        return false;
    }
  }

  /**
   * Create a call record for an inbound call.
   */
  private createInboundCall(
    providerCallId: string,
    from: string,
    to: string,
  ): CallRecord {
    const callId = crypto.randomUUID();

    const callRecord: CallRecord = {
      callId,
      providerCallId,
      provider: this.provider?.name || "twilio",
      direction: "inbound",
      state: "ringing",
      from,
      to,
      startedAt: Date.now(),
      transcript: [],
      processedEventIds: [],
      metadata: {
        initialMessage:
          this.config.inboundGreeting || "Hello! How can I help you today?",
      },
    };

    this.activeCalls.set(callId, callRecord);
    this.providerCallIdMap.set(providerCallId, callId); // Map providerCallId to internal callId
    this.persistCallRecord(callRecord);

    console.log(
      `[voice-call] Created inbound call record: ${callId} from ${from}`,
    );
    return callRecord;
  }

  /**
   * Look up a call by either internal callId or providerCallId.
   */
  private findCall(callIdOrProviderCallId: string): CallRecord | undefined {
    // Try direct lookup by internal callId
    const directCall = this.activeCalls.get(callIdOrProviderCallId);
    if (directCall) return directCall;

    // Try lookup by providerCallId
    return this.getCallByProviderCallId(callIdOrProviderCallId);
  }

  /**
   * Process a webhook event.
   */
  processEvent(event: NormalizedEvent): void {
    // Idempotency check
    if (this.processedEventIds.has(event.id)) {
      return;
    }
    this.processedEventIds.add(event.id);

    let call = this.findCall(event.callId);

    // Handle inbound calls - create record if it doesn't exist
    if (!call && event.direction === "inbound" && event.providerCallId) {
      // Check if we should accept this inbound call
      if (!this.shouldAcceptInbound(event.from)) {
        // TODO: Could hang up the call here
        return;
      }

      // Create a new call record for this inbound call
      call = this.createInboundCall(
        event.providerCallId,
        event.from || "unknown",
        event.to || this.config.fromNumber || "unknown",
      );

      // Update the event's callId to use our internal ID
      event.callId = call.callId;
    }

    if (!call) {
      // Still no call record - ignore event
      return;
    }

    // Update provider call ID if we got it
    if (event.providerCallId && event.providerCallId !== call.providerCallId) {
      const previousProviderCallId = call.providerCallId;
      call.providerCallId = event.providerCallId;
      this.providerCallIdMap.set(event.providerCallId, call.callId);
      if (previousProviderCallId) {
        const mapped = this.providerCallIdMap.get(previousProviderCallId);
        if (mapped === call.callId) {
          this.providerCallIdMap.delete(previousProviderCallId);
        }
      }
    }

    // Track processed event
    call.processedEventIds.push(event.id);

    // Process event based on type
    switch (event.type) {
      case "call.initiated":
        this.transitionState(call, "initiated");
        break;

      case "call.ringing":
        this.transitionState(call, "ringing");
        break;

      case "call.answered":
        call.answeredAt = event.timestamp;
        this.transitionState(call, "answered");
        // Start max duration timer when call is answered
        this.startMaxDurationTimer(call.callId);
        // Best-effort: speak initial message (for inbound greetings and outbound
        // conversation mode) once the call is answered.
        this.maybeSpeakInitialMessageOnAnswered(call);
        break;

      case "call.active":
        this.transitionState(call, "active");
        break;

      case "call.speaking":
        this.transitionState(call, "speaking");
        break;

      case "call.speech":
        if (event.isFinal) {
          this.addTranscriptEntry(call, "user", event.transcript);
          this.resolveTranscriptWaiter(call.callId, event.transcript);
        }
        this.transitionState(call, "listening");
        break;

      case "call.ended":
        call.endedAt = event.timestamp;
        call.endReason = event.reason;
        this.transitionState(call, event.reason as CallState);
        this.clearMaxDurationTimer(call.callId);
        this.rejectTranscriptWaiter(call.callId, `Call ended: ${event.reason}`);
        this.activeCalls.delete(call.callId);
        if (call.providerCallId) {
          this.providerCallIdMap.delete(call.providerCallId);
        }
        break;

      case "call.error":
        if (!event.retryable) {
          call.endedAt = event.timestamp;
          call.endReason = "error";
          this.transitionState(call, "error");
          this.clearMaxDurationTimer(call.callId);
          this.rejectTranscriptWaiter(
            call.callId,
            `Call error: ${event.error}`,
          );
          this.activeCalls.delete(call.callId);
          if (call.providerCallId) {
            this.providerCallIdMap.delete(call.providerCallId);
          }
        }
        break;
    }

    this.persistCallRecord(call);
  }

  private maybeSpeakInitialMessageOnAnswered(call: CallRecord): void {
    const initialMessage =
      typeof call.metadata?.initialMessage === "string"
        ? call.metadata.initialMessage.trim()
        : "";

    if (!initialMessage) return;

    if (!this.provider || !call.providerCallId) return;

    // Twilio has provider-specific state for speaking (<Say> fallback) and can
    // fail for inbound calls; keep existing Twilio behavior unchanged.
    if (this.provider.name === "twilio") return;

    void this.speakInitialMessage(call.providerCallId);
  }

  /**
   * Get an active call by ID.
   */
  getCall(callId: CallId): CallRecord | undefined {
    return this.activeCalls.get(callId);
  }

  /**
   * Get an active call by provider call ID (e.g., Twilio CallSid).
   */
  getCallByProviderCallId(providerCallId: string): CallRecord | undefined {
    // Fast path: use the providerCallIdMap for O(1) lookup
    const callId = this.providerCallIdMap.get(providerCallId);
    if (callId) {
      return this.activeCalls.get(callId);
    }

    // Fallback: linear search for cases where map wasn't populated
    // (e.g., providerCallId set directly on call record)
    for (const call of this.activeCalls.values()) {
      if (call.providerCallId === providerCallId) {
        return call;
      }
    }
    return undefined;
  }

  /**
   * Get all active calls.
   */
  getActiveCalls(): CallRecord[] {
    return Array.from(this.activeCalls.values());
  }

  /**
   * Get call history (from persisted logs).
   */
  async getCallHistory(limit = 50): Promise<CallRecord[]> {
    const logPath = path.join(this.storePath, "calls.jsonl");

    try {
      await fsp.access(logPath);
    } catch {
      return [];
    }

    const content = await fsp.readFile(logPath, "utf-8");
    const lines = content.trim().split("\n").filter(Boolean);
    const calls: CallRecord[] = [];

    // Parse last N lines
    for (const line of lines.slice(-limit)) {
      try {
        const parsed = CallRecordSchema.parse(JSON.parse(line));
        calls.push(parsed);
      } catch {
        // Skip invalid lines
      }
    }

    return calls;
  }

  // States that can cycle during multi-turn conversations
  private static readonly ConversationStates = new Set<CallState>([
    "speaking",
    "listening",
  ]);

  // Non-terminal state order for monotonic transitions
  private static readonly StateOrder: readonly CallState[] = [
    "initiated",
    "ringing",
    "answered",
    "active",
    "speaking",
    "listening",
  ];

  /**
   * Transition call state with monotonic enforcement.
   */
  private transitionState(call: CallRecord, newState: CallState): void {
    // No-op for same state or already terminal
    if (call.state === newState || TerminalStates.has(call.state)) return;

    // Terminal states can always be reached from non-terminal
    if (TerminalStates.has(newState)) {
      call.state = newState;
      return;
    }

    // Allow cycling between speaking and listening (multi-turn conversations)
    if (
      CallManager.ConversationStates.has(call.state) &&
      CallManager.ConversationStates.has(newState)
    ) {
      call.state = newState;
      return;
    }

    // Only allow forward transitions in state order
    const currentIndex = CallManager.StateOrder.indexOf(call.state);
    const newIndex = CallManager.StateOrder.indexOf(newState);

    if (newIndex > currentIndex) {
      call.state = newState;
    }
  }

  /**
   * Add an entry to the call transcript.
   */
  private addTranscriptEntry(
    call: CallRecord,
    speaker: "bot" | "user",
    text: string,
  ): void {
    const entry: TranscriptEntry = {
      timestamp: Date.now(),
      speaker,
      text,
      isFinal: true,
    };
    call.transcript.push(entry);
  }

  /**
   * Persist a call record to disk (fire-and-forget async).
   */
  private persistCallRecord(call: CallRecord): void {
    const logPath = path.join(this.storePath, "calls.jsonl");
    const line = `${JSON.stringify(call)}\n`;
    // Fire-and-forget async write to avoid blocking event loop
    fsp.appendFile(logPath, line).catch((err) => {
      console.error("[voice-call] Failed to persist call record:", err);
    });
  }

  /**
   * Load active calls from persistence (for crash recovery).
   * Uses streaming to handle large log files efficiently.
   */
  private loadActiveCalls(): void {
    const logPath = path.join(this.storePath, "calls.jsonl");
    if (!fs.existsSync(logPath)) return;

    // Read file synchronously and parse lines
    const content = fs.readFileSync(logPath, "utf-8");
    const lines = content.split("\n");

    // Build map of latest state per call
    const callMap = new Map<CallId, CallRecord>();

    for (const line of lines) {
      if (!line.trim()) continue;
      try {
        const call = CallRecordSchema.parse(JSON.parse(line));
        callMap.set(call.callId, call);
      } catch {
        // Skip invalid lines
      }
    }

    // Only keep non-terminal calls
    for (const [callId, call] of callMap) {
      if (!TerminalStates.has(call.state)) {
        this.activeCalls.set(callId, call);
        // Populate providerCallId mapping for lookups
        if (call.providerCallId) {
          this.providerCallIdMap.set(call.providerCallId, callId);
        }
        // Populate processed event IDs
        for (const eventId of call.processedEventIds) {
          this.processedEventIds.add(eventId);
        }
      }
    }
  }

  /**
   * Generate TwiML for notify mode (speak message and hang up).
   */
  private generateNotifyTwiml(message: string, voice: string): string {
    return `<?xml version="1.0" encoding="UTF-8"?>
<Response>
  <Say voice="${voice}">${escapeXml(message)}</Say>
  <Hangup/>
</Response>`;
  }
}