import axios from 'axios';

// In development, the API URL is '/api', but in production, it's just '/'
const API_URL = '';

// Define types based on the backend API
export interface NewGameOptions {
  player_color: 'white' | 'black';
  difficulty: 'beginner' | 'easy' | 'medium' | 'hard' | 'expert' | 'master';
  time_limit: number;
  use_opening_book: boolean;
  enable_analysis: boolean;
}

export interface MoveRequest {
  move: string;
}

// Promotion-related types
export type PromotionPiece = 'queen' | 'rook' | 'bishop' | 'knight';

export interface PromotionMove {
  from: string;           // e.g., "e7"
  to: string;             // e.g., "e8"
  piece?: PromotionPiece; // promotion piece selection
  required: boolean;      // true if promotion piece selection is required
}

export interface PromotionRequirement {
  from: string;
  to: string;
  available_pieces: PromotionPiece[];
}

export interface PromotionRequest {
  move: string;
  promotion_piece: PromotionPiece;
}

export interface GameState {
  fen: string;
  turn: 'white' | 'black';
  game_state: string;
  legal_moves: string[];
  in_check: boolean;
  move_count: number;
}

export interface GameResponse {
  status: string;
  message?: string;
  board_state: GameState;
  player_color?: 'white' | 'black';
  player_move?: string;
  ai_move?: string;
  analysis?: any;
  result?: string;
  winner?: string;
  reason?: string;
  // Promotion support
  promotion_required?: PromotionRequirement;
}

export interface HintResponse {
  status: string;
  hint: string;
  explanation: string;
  board_state: GameState;
}

// API functions
export const startNewGame = async (options: NewGameOptions): Promise<GameResponse> => {
  const response = await axios.post(`${API_URL}/game/new`, options);
  return response.data;
};

export const makeMove = async (move: string, promotionPiece?: PromotionPiece): Promise<GameResponse> => {
  try {
    // If promotion piece is specified, append it to the move in UCI notation
    const moveWithPromotion = promotionPiece ? createPromotionMove(move.substring(0, 2), move.substring(2, 4), promotionPiece) : move;
    
    const response = await axios.post(`${API_URL}/game/move`, { move: moveWithPromotion });
    return response.data;
  } catch (error) {
    // Handle promotion-required errors specifically
    if (axios.isAxiosError(error) && error.response?.status === 400) {
      const errorData = error.response.data;
      
      // Check if this is a promotion-required error
      if (errorData.status === 'promotion_required' || errorData.promotion_details) {
        return {
          status: 'promotion_required',
          message: errorData.message || 'Pawn promotion requires piece selection',
          board_state: errorData.board_state || {} as GameState,
          promotion_required: {
            from: errorData.promotion_details?.from || move.substring(0, 2),
            to: errorData.promotion_details?.to || move.substring(2, 4),
            available_pieces: errorData.promotion_details?.available_pieces || ['queen', 'rook', 'bishop', 'knight']
          }
        };
      }
    }
    
    // Re-throw other errors
    throw error;
  }
};

export const getGameState = async (): Promise<GameResponse> => {
  const response = await axios.get(`${API_URL}/game/state`);
  return response.data;
};

export const getHint = async (): Promise<HintResponse> => {
  const response = await axios.post(`${API_URL}/game/hint`);
  return response.data;
};

export const undoMove = async (count: number = 2): Promise<GameResponse> => {
  const response = await axios.post(`${API_URL}/game/undo`, { count });
  return response.data;
};

export const resignGame = async (): Promise<GameResponse> => {
  const response = await axios.post(`${API_URL}/game/resign`);
  return response.data;
};

// Utility functions for promotion handling
export const isPromotionRequired = (response: GameResponse): boolean => {
  return response.status === 'promotion_required' && !!response.promotion_required;
};

export const getPromotionRequirement = (response: GameResponse): PromotionRequirement | null => {
  return response.promotion_required || null;
};

export const createPromotionMove = (from: string, to: string, piece: PromotionPiece): string => {
  // Map promotion pieces to UCI notation
  const pieceMap: Record<PromotionPiece, string> = {
    'queen': 'q',
    'rook': 'r',
    'bishop': 'b',
    'knight': 'n'  // Knight uses 'n' in UCI notation, not 'k'
  };
  
  return `${from}${to}${pieceMap[piece]}`;
};