/**
 * Turn-based speaking manager for group channels.
 *
 * Maintains per-channel turn order so that only one agent speaks at a time.
 * When the current speaker finishes (end symbol or NO_REPLY), the turn advances
 * to the next agent in the rotation.
 */

export type TurnPolicy = {
  /** Ordered list of Discord account IDs (bot user IDs) that participate in turn rotation */
  turnOrder: string[];
};

export type ChannelTurnState = {
  /** Index into turnOrder for the current speaker */
  currentIndex: number;
  /** Timestamp of last turn advance */
  lastAdvancedAt: number;
};

/** In-memory turn state per channel */
const channelTurns = new Map<string, ChannelTurnState>();

/** Turn policies per channel (loaded from channel policies) */
const turnPolicies = new Map<string, TurnPolicy>();

/** Turn timeout: if the current speaker hasn't responded in this time, auto-advance */
const TURN_TIMEOUT_MS = 30_000;

export function setTurnPolicy(channelId: string, policy: TurnPolicy | undefined): void {
  if (!policy || !policy.turnOrder?.length) {
    turnPolicies.delete(channelId);
    channelTurns.delete(channelId);
    return;
  }
  turnPolicies.set(channelId, policy);
  // Initialize turn state if not exists
  if (!channelTurns.has(channelId)) {
    channelTurns.set(channelId, { currentIndex: 0, lastAdvancedAt: Date.now() });
  }
}

export function getTurnPolicy(channelId: string): TurnPolicy | undefined {
  return turnPolicies.get(channelId);
}

export function getTurnState(channelId: string): ChannelTurnState | undefined {
  return channelTurns.get(channelId);
}

/**
 * Check if the given accountId is the current speaker for this channel.
 * Returns: { isSpeaker: true } or { isSpeaker: false, reason: string }
 */
export function checkTurn(channelId: string, accountId: string): { isSpeaker: boolean; currentSpeaker?: string; reason: string } {
  const policy = turnPolicies.get(channelId);
  if (!policy) {
    return { isSpeaker: true, reason: "no_turn_policy" };
  }

  const order = policy.turnOrder;
  if (!order.includes(accountId)) {
    // Not in turn order — could be human or unmanaged agent, allow through
    return { isSpeaker: true, reason: "not_in_turn_order" };
  }

  let state = channelTurns.get(channelId);
  if (!state) {
    state = { currentIndex: 0, lastAdvancedAt: Date.now() };
    channelTurns.set(channelId, state);
  }

  // Auto-advance if turn has timed out
  const now = Date.now();
  if (now - state.lastAdvancedAt > TURN_TIMEOUT_MS) {
    advanceTurn(channelId);
    state = channelTurns.get(channelId)!;
  }

  const currentSpeaker = order[state.currentIndex];
  if (accountId === currentSpeaker) {
    return { isSpeaker: true, currentSpeaker, reason: "is_current_speaker" };
  }

  return { isSpeaker: false, currentSpeaker, reason: "not_current_speaker" };
}

/**
 * Advance turn to the next agent in rotation.
 * Returns the new current speaker's accountId.
 */
export function advanceTurn(channelId: string): string | undefined {
  const policy = turnPolicies.get(channelId);
  if (!policy) return undefined;

  const order = policy.turnOrder;
  let state = channelTurns.get(channelId);
  if (!state) {
    state = { currentIndex: 0, lastAdvancedAt: Date.now() };
    channelTurns.set(channelId, state);
    return order[0];
  }

  state.currentIndex = (state.currentIndex + 1) % order.length;
  state.lastAdvancedAt = Date.now();
  return order[state.currentIndex];
}

/**
 * Reset turn to the first agent (e.g., when a human sends a message).
 */
export function resetTurn(channelId: string): void {
  const state = channelTurns.get(channelId);
  if (state) {
    state.currentIndex = 0;
    state.lastAdvancedAt = Date.now();
  }
}

/**
 * Get debug info for a channel's turn state.
 */
export function getTurnDebugInfo(channelId: string): Record<string, unknown> {
  const policy = turnPolicies.get(channelId);
  const state = channelTurns.get(channelId);
  if (!policy) return { channelId, hasTurnPolicy: false };
  return {
    channelId,
    hasTurnPolicy: true,
    turnOrder: policy.turnOrder,
    currentIndex: state?.currentIndex ?? 0,
    currentSpeaker: policy.turnOrder[state?.currentIndex ?? 0],
    lastAdvancedAt: state?.lastAdvancedAt,
    timeSinceAdvanceMs: state ? Date.now() - state.lastAdvancedAt : null,
  };
}