import {type Dispatch, type SetStateAction,useState} from 'react';

import {
  generateCharacterPanelChatSuggestions,
  generateCharacterPanelChatSummary,
  streamCharacterPanelChatReply,
} from '../../services/aiService';
import type {StoryGenerationContext} from '../../services/aiTypes';
import type {
  Character,
  CharacterChatRecord,
  CharacterChatTurn,
  GameState,
} from '../../types';

const MAX_CHARACTER_CHAT_TURNS = 24;

export type CharacterChatTarget = {
  character: Character;
  npcId: string | null;
  roleLabel: string;
  hp: number;
  maxHp: number;
  mana: number;
  maxMana: number;
  affinity?: number | null;
};

export type CharacterChatModalState = {
  target: CharacterChatTarget;
  draft: string;
  messages: CharacterChatTurn[];
  suggestions: string[];
  summary: string;
  isSending: boolean;
  isLoadingSuggestions: boolean;
  error: string | null;
};

export interface CharacterChatUi {
  modal: CharacterChatModalState | null;
  openChat: (target: CharacterChatTarget) => void;
  closeChat: () => void;
  setDraft: (value: string) => void;
  useSuggestion: (value: string) => void;
  refreshSuggestions: () => void;
  sendDraft: () => void;
}

export function getCharacterChatRecord(state: GameState, characterId: string): CharacterChatRecord {
  return state.characterChats[characterId] ?? {
    history: [],
    summary: '',
    updatedAt: null,
  };
}

export function trimCharacterChatHistory(history: CharacterChatTurn[]) {
  return history.slice(-MAX_CHARACTER_CHAT_TURNS);
}

export function buildLocalCharacterChatSummary(
  character: Character,
  history: CharacterChatTurn[],
  previousSummary: string,
) {
  const latestTurns = history
    .slice(-4)
    .map(turn => `${turn.speaker === 'player' ? '玩家' : character.name}: ${turn.text}`)
    .join(' ');

  const currentSummary = latestTurns
    ? `${character.name} 在私下对话中变得更加开放。最近的交流：${latestTurns}`
    : `${character.name} 愿意继续私下对话，并逐渐更加信任玩家。`;

  if (!previousSummary) {
    return currentSummary.slice(0, 118);
  }

  return `${previousSummary} ${currentSummary}`.slice(0, 118);
}

export function buildLocalCharacterChatSuggestions(character: Character) {
  return [
    '请更清楚地告诉我你的意思。',
    `${character.name}，你真正担心的是什么？`,
    '暂时放下大局。我想更好地了解你。',
  ];
}

function buildCharacterChatRecordUpdate(
  state: GameState,
  characterId: string,
  record: CharacterChatRecord,
) {
  return {
    ...state,
    characterChats: {
      ...state.characterChats,
      [characterId]: record,
    },
  };
}

type CharacterChatTargetStatus = {
  roleLabel: string;
  hp: number;
  maxHp: number;
  mana: number;
  maxMana: number;
  affinity?: number | null;
};

function buildTargetStatus(target: CharacterChatTarget): CharacterChatTargetStatus {
  return {
    roleLabel: target.roleLabel,
    hp: target.hp,
    maxHp: target.maxHp,
    mana: target.mana,
    maxMana: target.maxMana,
    affinity: target.affinity ?? null,
  };
}

export function useCharacterChatFlow({
  gameState,
  setGameState,
  buildStoryContextFromState,
}: {
  gameState: GameState;
  setGameState: Dispatch<SetStateAction<GameState>>;
  buildStoryContextFromState: (state: GameState) => StoryGenerationContext;
}) {
  const [characterChatModal, setCharacterChatModal] = useState<CharacterChatModalState | null>(null);

  const loadCharacterChatSuggestions = async (
    target: CharacterChatTarget,
    messages: CharacterChatTurn[],
    summary: string,
  ) => {
    if (!gameState.worldType || !gameState.playerCharacter) {
      setCharacterChatModal(current =>
        current && current.target.character.id === target.character.id
          ? {
              ...current,
              suggestions: buildLocalCharacterChatSuggestions(target.character),
              isLoadingSuggestions: false,
            }
          : current,
      );
      return;
    }

    setCharacterChatModal(current =>
      current && current.target.character.id === target.character.id
        ? {
            ...current,
            isLoadingSuggestions: true,
          }
        : current,
    );

    try {
      const suggestions = await generateCharacterPanelChatSuggestions(
        gameState.worldType,
        gameState.playerCharacter,
        target.character,
        gameState.storyHistory,
        buildStoryContextFromState(gameState),
        messages,
        summary,
        buildTargetStatus(target),
      );

      setCharacterChatModal(current =>
        current && current.target.character.id === target.character.id
          ? {
              ...current,
              suggestions,
              isLoadingSuggestions: false,
            }
          : current,
      );
    } catch (error) {
      console.error('Failed to generate character chat suggestions:', error);
      setCharacterChatModal(current =>
        current && current.target.character.id === target.character.id
          ? {
              ...current,
              suggestions: buildLocalCharacterChatSuggestions(target.character),
              isLoadingSuggestions: false,
            }
          : current,
      );
    }
  };

  const openCharacterChat = (target: CharacterChatTarget) => {
    const record = getCharacterChatRecord(gameState, target.character.id);

    setCharacterChatModal({
      target,
      draft: '',
      messages: record.history,
      suggestions: buildLocalCharacterChatSuggestions(target.character),
      summary: record.summary,
      isSending: false,
      isLoadingSuggestions: true,
      error: null,
    });

    void loadCharacterChatSuggestions(target, record.history, record.summary);
  };

  const sendCharacterChatDraft = async () => {
    if (!characterChatModal || !gameState.worldType || !gameState.playerCharacter) {
      return;
    }

    const draft = characterChatModal.draft.trim();
    if (!draft) {
      return;
    }

    const target = characterChatModal.target;
    const existingRecord = getCharacterChatRecord(gameState, target.character.id);
    const baseMessages = trimCharacterChatHistory(characterChatModal.messages);
    const nextMessages = trimCharacterChatHistory([
      ...baseMessages,
      {
        speaker: 'player' as const,
        text: draft,
      },
    ]);

    setCharacterChatModal(current =>
      current && current.target.character.id === target.character.id
        ? {
            ...current,
            draft: '',
            messages: [...nextMessages, {speaker: 'character', text: ''}],
            suggestions: [],
            isSending: true,
            isLoadingSuggestions: true,
            error: null,
          }
        : current,
    );

    let replyText = '';

    try {
      replyText = await streamCharacterPanelChatReply(
        gameState.worldType,
        gameState.playerCharacter,
        target.character,
        gameState.storyHistory,
        buildStoryContextFromState(gameState),
        nextMessages,
        existingRecord.summary,
        draft,
        buildTargetStatus(target),
        {
          onUpdate: text => {
            setCharacterChatModal(current =>
              current && current.target.character.id === target.character.id
                ? {
                    ...current,
                    messages: [...nextMessages, {speaker: 'character', text}],
                  }
                : current,
            );
          },
        },
      );
    } catch (error) {
      console.error('Failed to stream character panel chat reply:', error);
      setCharacterChatModal(current =>
        current && current.target.character.id === target.character.id
          ? {
              ...current,
              draft,
              messages: baseMessages,
              isSending: false,
              isLoadingSuggestions: false,
              error: error instanceof Error ? error.message : '未知智能生成错误',
              suggestions: current.suggestions.length > 0
                ? current.suggestions
                : buildLocalCharacterChatSuggestions(target.character),
            }
          : current,
      );
      return;
    }

    const finalMessages = trimCharacterChatHistory([
      ...nextMessages,
      {
        speaker: 'character' as const,
        text: replyText,
      },
    ]);

    let nextSummary = existingRecord.summary;
    try {
      nextSummary = await generateCharacterPanelChatSummary(
        gameState.worldType,
        gameState.playerCharacter,
        target.character,
        gameState.storyHistory,
        buildStoryContextFromState(gameState),
        finalMessages,
        existingRecord.summary,
        buildTargetStatus(target),
      );
    } catch (error) {
      console.error('Failed to summarize character chat:', error);
      nextSummary = buildLocalCharacterChatSummary(target.character, finalMessages, existingRecord.summary);
    }

    const nextRecord: CharacterChatRecord = {
      history: finalMessages,
      summary: nextSummary,
      updatedAt: new Date().toISOString(),
    };

    setGameState(current =>
      buildCharacterChatRecordUpdate(current, target.character.id, nextRecord),
    );
    setCharacterChatModal(current =>
      current && current.target.character.id === target.character.id
        ? {
            ...current,
            messages: finalMessages,
            summary: nextSummary,
            isSending: false,
            error: null,
          }
        : current,
    );

    await loadCharacterChatSuggestions(target, finalMessages, nextSummary);
  };

  const characterChatUi: CharacterChatUi = {
    modal: characterChatModal,
    openChat: openCharacterChat,
    closeChat: () => setCharacterChatModal(null),
    setDraft: (value: string) => setCharacterChatModal(current => (current ? {...current, draft: value} : current)),
    useSuggestion: (value: string) => setCharacterChatModal(current => (current ? {...current, draft: value} : current)),
    refreshSuggestions: () => {
      if (!characterChatModal) {
        return;
      }

      void loadCharacterChatSuggestions(
        characterChatModal.target,
        characterChatModal.messages,
        characterChatModal.summary,
      );
    },
    sendDraft: () => {
      void sendCharacterChatDraft();
    },
  };

  return {
    characterChatModal,
    setCharacterChatModal,
    characterChatUi,
    openCharacterChat,
    sendCharacterChatDraft,
    loadCharacterChatSuggestions,
    clearCharacterChatModal: () => setCharacterChatModal(null),
  };
}