#include "types.h"
#include "help.h"
#include "moves.h"
#include <stddef.h>
#include <ctype.h>
#include <stdio.h>

#define PAWN_VALUE 100
#define KNIGHT_VALUE 320
#define BISHOP_VALUE 330
#define ROOK_VALUE 500
#define QUEEN_VALUE 900
#define KING_VALUE 20000
#define INF 9000000
#define MAX_DEPTH 3

int evaluateBoard(game *game);
void makeMove(game *g, move* m);
int negamax(game *g, int depth, int alpha, int beta, int color);

move *findBest(move* moves, size_t size, game* g){
  int bestScore = -INF;
  move *bestMove = NULL;
  int color = g->whiteToMove ? 1 : -1;

  for (int i = 0; i < size; i++) {
    game gg = *g;
    makeMove(&gg, &moves[i]);
    int score = -negamax(&gg, MAX_DEPTH, -INF, INF, -color);
    if (score > bestScore || bestScore == -INF) {
      bestScore = score;
      bestMove = &moves[i];
      printf("info score cp %d\n", g->whiteToMove ? bestScore : -bestScore);
    }
  }
  return bestMove;
}

int evaluateBoard(game *game) {
    int score = 0;
    score += __builtin_popcountll(game->white.pawns) * PAWN_VALUE;
    score += __builtin_popcountll(game->white.knights) * KNIGHT_VALUE;
    score += __builtin_popcountll(game->white.bishops) * BISHOP_VALUE;
    score += __builtin_popcountll(game->white.rooks) * ROOK_VALUE;
    score += __builtin_popcountll(game->white.queen) * QUEEN_VALUE;
    score += __builtin_popcountll(game->white.king) * KING_VALUE;

    score -= __builtin_popcountll(game->black.pawns) * PAWN_VALUE;
    score -= __builtin_popcountll(game->black.knights) * KNIGHT_VALUE;
    score -= __builtin_popcountll(game->black.bishops) * BISHOP_VALUE;
    score -= __builtin_popcountll(game->black.rooks) * ROOK_VALUE;
    score -= __builtin_popcountll(game->black.queen) * QUEEN_VALUE;
    score -= __builtin_popcountll(game->black.king) * KING_VALUE;

    return score;
}

void makeMove(game *g, move* m) {
  unsigned long long from_bit = 1ULL << m->From;
  unsigned long long to_bit = 1ULL << m->To;

  unsigned long long *set = findSet(g, from_bit);
  if (!set)
    return;
  *set &= ~from_bit;

  unsigned long long *captured = findSet(g, to_bit);
  if (captured) *captured &= ~to_bit;

  if (m->Promo) {
    char promoChar = g->whiteToMove ? toupper(m->Promo) : m->Promo;
    unsigned long long *newSet = charToSet(g, promoChar);
    if (newSet)
      *newSet |= to_bit;
  } else {
    *set |= to_bit;
  }

  g->whiteToMove = !g->whiteToMove;
}

int negamax(game *g, int depth, int alpha, int beta, int color) {
  if (depth == 0)
    return color * evaluateBoard(g);

  move moves[1500];
  int cnt = pawnMove(g, moves);
  cnt += knightMove(g, moves + cnt);
  cnt += rookMove(g, moves + cnt);
  cnt += bishopMove(g, moves + cnt);
  cnt += kingMove(g, moves + cnt);
  cnt += queenMove(g, moves + cnt);

  if (cnt == 0)
    return 0;

  int bestValue = -INF;
  for (int i = 0; i < cnt; i++) {
    game gg = *g;
    makeMove(&gg, &moves[i]);

    int value = -negamax(&gg, depth - 1, -beta, -alpha, -color);

    if (value > bestValue) bestValue = value;
    if (value > alpha) alpha = value;
    if (alpha >= beta) break;
  }
  return bestValue;
}