"use client";

import { useCallback, useEffect, useMemo, useRef, useState } from 'react';
import { Node } from '@/types/database';
import AsciiBanner from './AsciiBanner';
import TerminalMessage from './TerminalMessage';
import TerminalInput from './TerminalInput';
import { Zap, Flame } from 'lucide-react';
import { useSSEChat, ChatMessage, MessageRole } from './hooks/useSSEChat';
import { useQuotaHandler } from '@/hooks/useQuotaHandler';
import { apiKeyService } from '@/services/storage/apiKeys';

// Stub type for delegation (delegation system removed in rah-light)
type AgentDelegation = {
  id: number;
  sessionId: string;
  task: string;
  status: 'queued' | 'in_progress' | 'completed' | 'failed';
  summary?: string | null;
  agentType: string;
  createdAt: string;
  updatedAt: string;
};

// Stub DelegationIndicator component (delegation system removed)
function DelegationIndicator({ delegations }: { delegations: AgentDelegation[] }) {
  return null;
}

// Stub voice hooks (voice system will be removed in story 2)
function useVoiceSession() {
  return {
    isActive: false,
    amplitude: 0,
    startSession: () => {},
    stopSession: () => {},
    resetTranscript: () => {},
    setStatus: (_status: string) => {},
    setAmplitude: (_amp: number) => {},
    setInterimTranscript: (_text: string) => {},
    appendFinalTranscript: (_text: string) => {},
  };
}

function useAssistantTTS(_options: { onSpeechStart?: () => void; onSpeechComplete?: () => void; onError?: (e: Error) => void }) {
  return {
    speak: (_text: string, _options?: { flush?: boolean; metadata?: Record<string, string> }) => {},
    stop: () => {},
    status: 'idle' as const,
  };
}

function useVoiceInterruption(_options: { amplitude: number; isVoiceActive: boolean; ttsStatus: string; onInterruption: () => void }) {}

function useRealtimeVoiceClient(_handlers: { onStatusChange?: (status: string) => void; onInterimTranscript?: (text: string) => void; onFinalTranscript?: (text: string) => void; onAmplitude?: (amp: number) => void; onError?: (e: Error) => void }, _options: { getAuthToken: () => string | null }) {
  return {
    connect: () => {},
    disconnect: () => {},
    start: () => {},
    stop: () => {},
  };
}

const createSessionId = () => `session_${Date.now()}_${Math.random().toString(36).slice(2, 8)}`;
const createVoiceRequestId = () =>
  typeof crypto !== 'undefined' && typeof crypto.randomUUID === 'function'
    ? crypto.randomUUID()
    : `voice_${Date.now()}_${Math.random().toString(36).slice(2, 8)}`;

interface HighlightedPassage {
  selectedText: string;
  nodeId: number;
  nodeTitle: string;
}

interface RAHChatProps {
  openTabsData: Node[];
  activeTabId: number | null;
  activeDimension?: string | null;
  onClearDimension?: () => void;
  onNodeClick?: (nodeId: number) => void;
  delegations?: AgentDelegation[];
  messages?: ChatMessage[];
  setMessages?: (updater: (prev: ChatMessage[]) => ChatMessage[]) => void;
  mode?: 'easy' | 'hard';
  delegationMode?: boolean;
  delegationSessionId?: string;
  onQuickAdd?: () => void;
  highlightedPassage?: HighlightedPassage | null;
  onClearPassage?: () => void;
}

export default function RAHChat({
  openTabsData,
  activeTabId,
  activeDimension,
  onClearDimension: _onClearDimension,
  onNodeClick,
  delegations = [],
  messages: externalMessages,
  setMessages: externalSetMessages,
  mode = 'easy',
  delegationMode = false,
  delegationSessionId,
  onQuickAdd: _onQuickAdd,
  highlightedPassage: _highlightedPassage,
  onClearPassage: _onClearPassage,
}: RAHChatProps) {
  // Use external state if provided (lifted state), otherwise use local state
  const [internalMessages, internalSetMessages] = useState<ChatMessage[]>([]);
  const messages = externalMessages !== undefined ? externalMessages : internalMessages;
  const setMessages = externalSetMessages || internalSetMessages;
  
  const [sessionId, setSessionId] = useState(() => createSessionId());
  const messagesEndRef = useRef<HTMLDivElement>(null);
  const chatMode = mode === 'hard' ? 'hard' : 'easy';
  const helperKey = chatMode === 'hard' ? 'ra-h' : 'ra-h-easy';
  const helperDisplayName = helperKey === 'ra-h' ? 'ra-h (hard)' : 'ra-h (easy)';
  const {
    quotaError,
    handleAPIError: handleQuotaApiError,
    checkQuotaBeforeRequest,
    refetchUsage,
    isQuotaExceeded,
  } = useQuotaHandler();
  const streamCompleteHandlerRef = useRef<() => Promise<void> | void>(async () => {
    await refetchUsage();
  });
  const setMessagesRef = useRef(setMessages);
  const voice = useVoiceSession();
  const {
    isActive: isVoiceActive,
    amplitude: voiceAmplitude,
    startSession: startVoice,
    stopSession: stopVoice,
    resetTranscript: resetVoiceTranscript,
    setStatus: setVoiceStatus,
    setAmplitude: setVoiceAmplitude,
    setInterimTranscript,
    appendFinalTranscript,
  } = voice;
  const pendingVoiceQueueRef = useRef<{ text: string; queuedAt: number }[]>([]);
  const assistantSpeechMapRef = useRef<Map<string, string>>(new Map());
  const [voiceError, setVoiceError] = useState<string | null>(null);
  const voiceErrorHandledRef = useRef(false);
  const voiceStartTimestampRef = useRef<number | null>(null);

  const handleVoiceError = useCallback((error: Error) => {
    console.error('[RAHChat] Voice error:', error);
    setVoiceError(error.message);
    if (isVoiceActive) {
      stopVoice();
    }
    resetVoiceTranscript();
    setVoiceAmplitude(0);
    setVoiceStatus('idle');
    pendingVoiceQueueRef.current = [];
    assistantSpeechMapRef.current.clear();
  }, [isVoiceActive, resetVoiceTranscript, setVoiceAmplitude, setVoiceStatus, stopVoice]);

  const { speak: speakAssistantResponse, stop: stopAssistantTTS, status: ttsStatus } = useAssistantTTS({
    onSpeechStart: () => {
      if (isVoiceActive) {
        setVoiceStatus('speaking');
      }
    },
    onSpeechComplete: () => {
      setVoiceStatus(isVoiceActive ? 'listening' : 'idle');
    },
    onError: handleVoiceError,
  });

  const handleVoiceInterruption = useCallback(() => {
    stopAssistantTTS();
    setVoiceStatus('listening');
  }, [setVoiceStatus, stopAssistantTTS]);

  const sse = useSSEChat('/api/rah/chat', setMessages, {
    getAuthToken: () => null,
    beforeRequest: checkQuotaBeforeRequest,
    onRequestError: handleQuotaApiError,
    onStreamComplete: async () => {
      const handler = streamCompleteHandlerRef.current;
      if (handler) {
        await handler();
      }
    },
  });

  useVoiceInterruption({
    amplitude: voiceAmplitude,
    isVoiceActive,
    ttsStatus,
    onInterruption: handleVoiceInterruption,
  });


  const sendMessage = useCallback(async (text: string) => {
    if (delegationMode) return; // Delegation chats are read-only
    if (isQuotaExceeded) {
      checkQuotaBeforeRequest();
      return;
    }
    await sse.send({
      text,
      history: messages,
      openTabs: openTabsData,
      activeTabId,
      sessionId,
      mode: chatMode
    });
  }, [activeTabId, chatMode, checkQuotaBeforeRequest, delegationMode, isQuotaExceeded, messages, openTabsData, sse, sessionId]);

  const handleVoiceFinalTranscript = useCallback(
    (raw: string) => {
      const normalized = raw.trim();
      console.info('[RAHVoice] Final transcript received:', normalized || '(empty)');
      setInterimTranscript('');
      if (!normalized) {
        console.info('[RAHVoice] Ignoring empty transcript');
        return;
      }
      appendFinalTranscript(normalized);
      if (sse.isLoading) {
        pendingVoiceQueueRef.current.push({ text: normalized, queuedAt: Date.now() });
        console.info('[RAHVoice] SSE busy, queueing transcript', {
          queuedCount: pendingVoiceQueueRef.current.length,
        });
        setVoiceStatus('thinking');
        return;
      }
      setVoiceStatus('thinking');
      console.info('[RAHVoice] Dispatching transcript to /api/rah/chat');
      void sendMessage(normalized);
    },
    [appendFinalTranscript, sendMessage, setInterimTranscript, setVoiceStatus, sse.isLoading]
  );

  const voiceRealtime = useRealtimeVoiceClient(
    {
      onStatusChange: (status) => {
        if (!isVoiceActive && status !== 'idle') return;
        if (status === 'listening' && (sse.isLoading || pendingVoiceQueueRef.current.length > 0)) {
          setVoiceStatus('thinking');
          return;
        }
        setVoiceStatus(status);
      },
      onInterimTranscript: setInterimTranscript,
      onFinalTranscript: handleVoiceFinalTranscript,
      onAmplitude: setVoiceAmplitude,
      onError: handleVoiceError,
    },
    {
      getAuthToken: () => null,
    }
  );

  const handleStreamComplete = useCallback(async () => {
    if (pendingVoiceQueueRef.current.length > 0) {
      console.info('[RAHVoice] SSE stream complete, draining queued transcripts', {
        queued: pendingVoiceQueueRef.current.length,
      });
    }
    while (pendingVoiceQueueRef.current.length > 0) {
      const nextQueued = pendingVoiceQueueRef.current.shift();
      if (!nextQueued) {
        break;
      }
      const queueLatency = Date.now() - nextQueued.queuedAt;
      setVoiceStatus('thinking');
      console.info('[RAHVoice] Dispatching queued transcript to /api/rah/chat', {
        queuedMs: queueLatency,
      });
      await sendMessage(nextQueued.text);
    }
    await refetchUsage();
  }, [sendMessage, setVoiceStatus, refetchUsage]);

  useEffect(() => {
    streamCompleteHandlerRef.current = handleStreamComplete;
  }, [handleStreamComplete]);

  useEffect(() => {
    setMessagesRef.current = setMessages;
  }, [setMessages]);

  useEffect(() => {
    if (!voiceError) {
      voiceErrorHandledRef.current = false;
      return;
    }
    if (voiceErrorHandledRef.current) return;
    voiceErrorHandledRef.current = true;
    voiceRealtime.stop();
    stopAssistantTTS();
  }, [voiceError, voiceRealtime, stopAssistantTTS]);

  const focusSummary = useMemo(() => {
    if (!openTabsData.length) return null;
    const titles = openTabsData.map((node) => node?.title || 'Untitled');
    const activeNode = openTabsData.find((node) => node.id === activeTabId) || openTabsData[0];
    const truncate = (value: string, limit = 64) => {
      if (value.length <= limit) return value;
      return `${value.slice(0, limit - 1)}…`;
    };
    return {
      id: activeNode?.id ?? null,
      title: truncate(activeNode?.title || 'Untitled'),
      total: titles.length,
    };
  }, [openTabsData, activeTabId]);

  useEffect(() => {
    messagesEndRef.current?.scrollIntoView({ behavior: 'smooth' });
  }, [messages]);

  useEffect(() => {
    if (!isVoiceActive) {
      assistantSpeechMapRef.current.clear();
      stopAssistantTTS();
      return;
    }
    if (sse.isLoading) return;
    const assistantMessages = messages.filter((m) => m.role === MessageRole.ASSISTANT);
    if (!assistantMessages.length) return;
    const latest = assistantMessages[assistantMessages.length - 1];
    const spokenContent = assistantSpeechMapRef.current.get(latest.id);
    if (!latest.content.trim() || spokenContent === latest.content) return;
    assistantSpeechMapRef.current.set(latest.id, latest.content);
    const voiceRequestId = createVoiceRequestId();
    speakAssistantResponse(latest.content, {
      flush: true,
      metadata: {
        sessionId,
        helper: helperKey,
        requestId: voiceRequestId,
        messageId: latest.id,
      },
    });
  }, [helperKey, isVoiceActive, messages, sessionId, sse.isLoading, speakAssistantResponse, stopAssistantTTS]);


  const handleNewChat = () => {
    if (delegationMode) return;
    sse.abort();
    setMessages((_prev) => []);
    setSessionId(createSessionId());
    if (isVoiceActive) {
      stopVoice();
      resetVoiceTranscript();
    }
  };

  // Subscribe to delegation stream if in delegation mode
  useEffect(() => {
    if (!delegationMode || !delegationSessionId) return;

    const eventSource = new EventSource(`/api/rah/delegations/stream?sessionId=${delegationSessionId}`);

    eventSource.onmessage = (event) => {
      try {
        const data = JSON.parse(event.data);
        
        if (data.type === 'text-delta' && data.delta) {
          setMessagesRef.current((prev) => {
            const lastMsg = prev[prev.length - 1];
            if (lastMsg && lastMsg.role === MessageRole.ASSISTANT) {
              const updated = [...prev];
              updated[updated.length - 1] = { ...lastMsg, content: lastMsg.content + data.delta };
              return updated;
            }
            return [...prev, {
              id: crypto.randomUUID(),
              role: MessageRole.ASSISTANT,
              content: data.delta,
              timestamp: new Date()
            }];
          });
        }

        if (data.type === 'tool-input-start' || data.type === 'tool-call') {
          const toolMessage: ChatMessage = {
            id: `tool-${data.toolCallId || crypto.randomUUID()}`,
            role: MessageRole.TOOL,
            content: data.toolName,
            timestamp: new Date(),
            toolName: data.toolName,
            status: (data.status as ChatMessage['status']) || 'running',
            toolArgs: data.input ?? data.args ?? data.parameters
          };
          setMessagesRef.current((prev) => [...prev, toolMessage]);
        }

        if (data.type === 'tool-output-available' || data.type === 'tool-result') {
          setMessagesRef.current((prev) =>
            prev.map((m) =>
              m.id === `tool-${data.toolCallId}`
                ? {
                    ...m,
                    content: `${m.toolName} ${data.status === 'error' ? '✗' : '✓'}`,
                    status: (data.status as ChatMessage['status']) || (data.error ? 'error' : 'complete'),
                    toolResult: data.result ?? data.output ?? (data.summary ? { summary: data.summary } : undefined),
                  }
                : m
            )
          );
        }

        if (data.type === 'assistant-message') {
          setMessagesRef.current((prev) => [...prev, {
            id: crypto.randomUUID(),
            role: MessageRole.ASSISTANT,
            content: '',
            timestamp: new Date()
          }]);
        }
      } catch (error) {
        console.error('[RAHChat] Failed to parse delegation stream event:', error);
      }
    };

    eventSource.onerror = () => {
      console.error('[RAHChat] Delegation stream connection error');
    };

    return () => {
      eventSource.close();
    };
  }, [delegationMode, delegationSessionId]);

  useEffect(() => {
    if (delegationMode && isVoiceActive) {
      voiceRealtime.stop();
      stopVoice();
      resetVoiceTranscript();
      stopAssistantTTS();
    }
  }, [delegationMode, isVoiceActive, resetVoiceTranscript, stopAssistantTTS, stopVoice, voiceRealtime]);

  const handleVoiceToggle = useCallback(async () => {
    if (isVoiceActive) {
      voiceRealtime.stop();
      stopVoice();
      resetVoiceTranscript();
      setVoiceAmplitude(0);
      setVoiceStatus('idle');
      assistantSpeechMapRef.current.clear();
      pendingVoiceQueueRef.current = [];
      stopAssistantTTS();
      voiceStartTimestampRef.current = null;
      return;
    }
    setVoiceError(null);
    try {
      voiceStartTimestampRef.current = performance.now();
      console.info('[RAHVoice] Voice session starting');
      await voiceRealtime.start();
      startVoice();
      setVoiceStatus('listening');
    } catch (error) {
      voiceStartTimestampRef.current = null;
      handleVoiceError(error instanceof Error ? error : new Error(String(error)));
    }
  }, [
    handleVoiceError,
    isVoiceActive,
    resetVoiceTranscript,
    setVoiceAmplitude,
    setVoiceStatus,
    setVoiceError,
    startVoice,
    stopAssistantTTS,
    stopVoice,
    voiceRealtime,
  ]);

  return (
    <div style={{
      height: '100%',
      display: 'flex',
      flexDirection: 'column',
      background: '#0a0a0a'
    }}>
      {focusSummary && (
        <header style={{
          display: 'flex',
          alignItems: 'center',
          justifyContent: 'space-between',
          padding: '8px 16px',
          borderBottom: '1px solid #1a1a1a',
          background: '#0a0a0a'
        }}>
          {/* Focused node info */}
          <div style={{ display: 'flex', alignItems: 'center', gap: '12px', minWidth: 0, flex: 1 }}>
            <span style={{
              color: '#22c55e',
              fontSize: '10px',
              letterSpacing: '0.18em',
              textTransform: 'uppercase'
            }}>
              Focused Node ({focusSummary.total})
            </span>
            <span style={{ color: '#d0d0d0', fontSize: '10px' }}>#{focusSummary.id}</span>
            <span
              style={{
                color: '#f3f3f3',
                fontSize: '12px',
                fontWeight: 600,
                flex: 1,
                minWidth: 0,
                whiteSpace: 'nowrap',
                overflow: 'hidden',
                textOverflow: 'ellipsis'
              }}
              title={focusSummary.title}
            >
              {focusSummary.title}
            </span>
          </div>
          <DelegationIndicator delegations={delegations} />
        </header>
      )}

      <div style={{ flex: 1, overflow: 'auto', padding: '16px', background: '#0a0a0a' }}>
        {messages.length === 0 ? (
          <AsciiBanner helperName="ra-h" displayName={helperDisplayName} />
        ) : (
          <>
            {messages.map((message) => (
              <TerminalMessage
                key={message.id}
                role={message.role}
                content={message.content}
                timestamp={message.timestamp}
                toolName={message.toolName}
                status={message.status}
                toolArgs={message.toolArgs}
                toolResult={message.toolResult}
                onNodeClick={onNodeClick}
              />
            ))}
          </>
        )}
        {/* Voice transcript preview removed for streamlined UI */}
        <div ref={messagesEndRef} />
      </div>

      {!delegationMode && (
        <div style={{
          padding: '0 16px 16px',
          display: 'flex',
          flexDirection: 'column',
          gap: '12px'
        }}>
          {(quotaError || isQuotaExceeded) && (
            <div style={{
              background: 'rgba(239,68,68,0.12)',
              border: '1px solid rgba(239,68,68,0.35)',
              color: '#fca5a5',
              fontSize: '11px',
              padding: '10px 12px',
              borderRadius: '6px',
              lineHeight: 1.4
            }}>
              {quotaError?.message ?? 'Rate limit reached. Please wait a moment and try again.'}
            </div>
          )}
          <TerminalInput
            onSubmit={sendMessage}
            isProcessing={sse.isLoading || isQuotaExceeded}
            placeholder={isVoiceActive ? 'voice mode active — end session to type…' : `ask ${helperDisplayName}...`}
            helperId={activeTabId ?? undefined}
            disabledExternally={isVoiceActive}
            disabledMessage="voice mode active"
            onVoiceToggle={handleVoiceToggle}
            isVoiceActive={isVoiceActive}
            voiceAmplitude={voiceAmplitude}
            voiceError={voiceError || undefined}
          />
          <div style={{
            display: 'flex',
            alignItems: 'center',
            justifyContent: 'space-between',
            gap: '12px',
            flexWrap: 'wrap'
          }}>
            <div style={{ display: 'flex', alignItems: 'center', gap: '12px', flexWrap: 'wrap' }}>
              <ModelSelector chatMode={chatMode} />
            </div>
            <button
              onClick={handleNewChat}
              style={{
                background: 'none',
                border: 'none',
                color: '#fff',
                fontSize: '12px',
                cursor: 'pointer',
                padding: '4px 8px',
                transition: 'color 0.2s',
                fontFamily: 'inherit',
                display: 'flex',
                alignItems: 'center',
                gap: '6px',
                textTransform: 'uppercase',
                letterSpacing: '0.05em'
              }}
              onMouseEnter={(e) => {
                e.currentTarget.style.color = '#d0d0d0';
              }}
              onMouseLeave={(e) => {
                e.currentTarget.style.color = '#fff';
              }}
            >
              <span style={{ 
                display: 'flex',
                alignItems: 'center',
                justifyContent: 'center',
                width: '16px',
                height: '16px',
                borderRadius: '50%',
                background: '#fff',
                color: '#0a0a0a',
                fontSize: '12px',
                lineHeight: 1,
                fontWeight: 300,
                flexShrink: 0
              }}>+</span>
              New Chat
            </button>
          </div>
        </div>
      )}
    </div>
  );
}

interface ModelSelectorProps {
  chatMode: 'easy' | 'hard';
}

function ModelSelector({ chatMode }: ModelSelectorProps) {
  const [dropdownOpen, setDropdownOpen] = useState(false);
  
  const currentModel = chatMode === 'easy' ? 'Easy (GPT)' : 'Hard (Claude)';
  const Icon = chatMode === 'easy' ? Zap : Flame;
  const activeColor = chatMode === 'easy' ? '#22c55e' : '#f97316';

  const options = [
    { id: 'easy', label: 'Easy (GPT)', icon: Zap, color: '#22c55e' },
    { id: 'hard', label: 'Hard (Claude)', icon: Flame, color: '#f97316' },
    { id: 'soon', label: 'Ra-h (Soon)', icon: null, color: '#666', disabled: true }
  ];

  return (
    <div style={{ position: 'relative' }}>
      <button 
        onClick={() => setDropdownOpen(!dropdownOpen)}
        style={{
          display: 'flex',
          alignItems: 'center',
          gap: '6px',
          padding: '8px 12px',
          border: '1px solid #1a1a1a',
          borderRadius: '6px',
          background: '#0f0f0f',
          color: '#e5e5e5',
          fontSize: '12px',
          cursor: 'pointer',
          transition: 'all 0.2s'
        }}
        onMouseEnter={(e) => {
          e.currentTarget.style.borderColor = '#333';
        }}
        onMouseLeave={(e) => {
          e.currentTarget.style.borderColor = '#1a1a1a';
        }}
      >
        <Icon size={12} strokeWidth={2.4} color={activeColor} />
        {currentModel}
        <span style={{ 
          marginLeft: '4px', 
          transform: dropdownOpen ? 'rotate(180deg)' : 'rotate(0deg)',
          transition: 'transform 0.2s'
        }}>▲</span>
      </button>
      
      {dropdownOpen && (
        <div style={{
          position: 'absolute',
          bottom: '100%', /* Open upward */
          left: '0',
          marginBottom: '4px',
          background: '#1a1a1a',
          border: '1px solid #333',
          borderRadius: '6px',
          minWidth: '150px',
          zIndex: 1000,
          boxShadow: '0 4px 12px rgba(0, 0, 0, 0.4)'
        }}>
          {options.map((option) => {
            const OptionIcon = option.icon;
            const isActive = (option.id === 'easy' && chatMode === 'easy') || (option.id === 'hard' && chatMode === 'hard');
            
            return (
              <button
                key={option.id}
                onClick={() => {
                  if (!option.disabled && !isActive) {
                    window.dispatchEvent(new CustomEvent('rah:mode-toggle', { detail: { mode: option.id as 'easy' | 'hard' } }));
                  }
                  setDropdownOpen(false);
                }}
                disabled={option.disabled}
                style={{
                  width: '100%',
                  display: 'flex',
                  alignItems: 'center',
                  gap: '8px',
                  padding: '8px 12px',
                  border: 'none',
                  background: isActive ? 'rgba(34, 197, 94, 0.1)' : 'transparent',
                  color: option.disabled ? '#666' : (isActive ? '#22c55e' : '#e5e5e5'),
                  fontSize: '12px',
                  cursor: option.disabled ? 'not-allowed' : 'pointer',
                  transition: 'all 0.2s',
                  borderRadius: '4px'
                }}
                onMouseEnter={(e) => {
                  if (!option.disabled && !isActive) {
                    e.currentTarget.style.background = '#0a0a0a';
                  }
                }}
                onMouseLeave={(e) => {
                  if (!option.disabled && !isActive) {
                    e.currentTarget.style.background = 'transparent';
                  }
                }}
              >
                {OptionIcon && <OptionIcon size={12} strokeWidth={2} color={option.color} />}
                {!OptionIcon && <div style={{ width: '12px' }} />} {/* Spacer for alignment */}
                {option.label}
                {isActive && <span style={{ marginLeft: 'auto', color: '#22c55e' }}>✓</span>}
              </button>
            );
          })}
        </div>
      )}
    </div>
  );
}
