/**
 * useColdStart - Cold start state management hook
 *
 * Detects first-time users and manages the cold start greeting flow.
 * Reuses the onboarding completion key to determine if user is new.
 *
 * Flow: idle -> greeting_sent -> waiting_response -> completed
 */

import { useState, useEffect, useCallback } from 'react';
import { createLogger } from './logger';

const log = createLogger('useColdStart');

// Reuse the same key from use-onboarding.ts
const ONBOARDING_COMPLETED_KEY = 'zclaw-onboarding-completed';

// Cold start state persisted to localStorage
const COLD_START_STATE_KEY = 'zclaw-cold-start-state';

// Re-export UserProfile for consumers that need it
export type { UserProfile } from './use-onboarding';

// === Types ===

export type ColdStartPhase = 'idle' | 'greeting_sent' | 'waiting_response' | 'completed';

export interface ColdStartState {
  isColdStart: boolean;
  phase: ColdStartPhase;
  greetingSent: boolean;
  markGreetingSent: () => void;
  markWaitingResponse: () => void;
  markCompleted: () => void;
  getGreetingMessage: (agentName?: string, agentEmoji?: string) => string;
}

// === Default Greeting ===

const DEFAULT_GREETING_BODY =
  '我可以帮您处理写作、研究、数据分析、内容生成等各类任务。\n\n请告诉我您需要什么帮助？';

const FALLBACK_GREETING =
  '您好！我是您的工作助手。我可以帮您处理写作、研究、数据分析、内容生成等各类任务。请告诉我您需要什么帮助？';

// === Persistence Helpers ===

interface PersistedColdStart {
  phase: ColdStartPhase;
}

function loadPersistedPhase(): ColdStartPhase {
  try {
    const raw = localStorage.getItem(COLD_START_STATE_KEY);
    if (raw) {
      const parsed = JSON.parse(raw) as PersistedColdStart;
      if (parsed && typeof parsed.phase === 'string') {
        return parsed.phase;
      }
    }
  } catch (err) {
    log.warn('Failed to read cold start state:', err);
  }
  return 'idle';
}

function persistPhase(phase: ColdStartPhase): void {
  try {
    const data: PersistedColdStart = { phase };
    localStorage.setItem(COLD_START_STATE_KEY, JSON.stringify(data));
  } catch (err) {
    log.warn('Failed to persist cold start state:', err);
  }
}

// === Greeting Builder ===

function buildGreeting(agentName?: string, agentEmoji?: string): string {
  if (!agentName) {
    return FALLBACK_GREETING;
  }

  const emoji = agentEmoji ? ` ${agentEmoji}` : '';
  return `您好！我是${agentName}${emoji}\n\n${DEFAULT_GREETING_BODY}`;
}

// === Hook ===

/**
 * Hook to manage cold start state for first-time users.
 *
 * A user is considered "cold start" when they have not completed onboarding
 * AND have not yet gone through the greeting flow.
 *
 * Usage:
 * ```tsx
 * const { isColdStart, phase, markGreetingSent, getGreetingMessage } = useColdStart();
 *
 * if (isColdStart && phase === 'idle') {
 *   const msg = getGreetingMessage(agent.name, agent.emoji);
 *   sendMessage(msg);
 *   markGreetingSent();
 * }
 * ```
 */
export function useColdStart(): ColdStartState {
  const [phase, setPhase] = useState<ColdStartPhase>(loadPersistedPhase);
  const [isColdStart, setIsColdStart] = useState(false);

  // Determine cold start status on mount
  useEffect(() => {
    try {
      const onboardingCompleted = localStorage.getItem(ONBOARDING_COMPLETED_KEY);
      const isNewUser = onboardingCompleted !== 'true';

      if (isNewUser && phase !== 'completed') {
        setIsColdStart(true);
      } else {
        setIsColdStart(false);
        // If onboarding is completed but phase is not completed,
        // force phase to completed to avoid stuck states
        if (phase !== 'completed') {
          setPhase('completed');
          persistPhase('completed');
        }
      }
    } catch (err) {
      log.warn('Failed to check cold start status:', err);
      setIsColdStart(false);
    }
  }, [phase]);

  const markGreetingSent = useCallback(() => {
    const nextPhase: ColdStartPhase = 'greeting_sent';
    setPhase(nextPhase);
    persistPhase(nextPhase);
    log.debug('Cold start: greeting sent');
  }, []);

  const markWaitingResponse = useCallback(() => {
    const nextPhase: ColdStartPhase = 'waiting_response';
    setPhase(nextPhase);
    persistPhase(nextPhase);
    log.debug('Cold start: waiting for user response');
  }, []);

  const markCompleted = useCallback(() => {
    const nextPhase: ColdStartPhase = 'completed';
    setPhase(nextPhase);
    persistPhase(nextPhase);
    setIsColdStart(false);
    log.debug('Cold start: completed');
  }, []);

  const getGreetingMessage = useCallback(
    (agentName?: string, agentEmoji?: string): string => {
      return buildGreeting(agentName, agentEmoji);
    },
    [],
  );

  return {
    isColdStart,
    phase,
    greetingSent: phase === 'greeting_sent' || phase === 'waiting_response' || phase === 'completed',
    markGreetingSent,
    markWaitingResponse,
    markCompleted,
    getGreetingMessage,
  };
}

// === Non-hook Accessor ===

/**
 * Get cold start state without React hook (for use outside components).
 */
export function getColdStartState(): { isColdStart: boolean; phase: ColdStartPhase } {
  try {
    const onboardingCompleted = localStorage.getItem(ONBOARDING_COMPLETED_KEY);
    const isNewUser = onboardingCompleted !== 'true';
    const phase = loadPersistedPhase();

    return {
      isColdStart: isNewUser && phase !== 'completed',
      phase,
    };
  } catch (err) {
    log.warn('Failed to get cold start state:', err);
    return { isColdStart: false, phase: 'completed' };
  }
}

/**
 * Reset cold start state (for testing or debugging).
 */
export function resetColdStartState(): void {
  try {
    localStorage.removeItem(COLD_START_STATE_KEY);
    log.debug('Cold start state reset');
  } catch (err) {
    log.warn('Failed to reset cold start state:', err);
  }
}

export default useColdStart;