#include <string.h>
#include <assert.h>
#include <stdlib.h>

#include "response.h"
#include "../fen.h"
#include "../bitboard.h"

void apply_option(uci_state *state, char *name, char *buffer) {
  int settings_count = sizeof(state->option_settings)/sizeof(option_setting_t);
  for (int i = 0; i < settings_count; i++) {
    option_setting_t setting = state->option_settings[i];

    if (strcmp(setting.option_name, name)) continue;
    if (OPTION_SPIN == setting.type) {
      option_spin_setting_t data = setting.data.spin;
      int num = atoi(buffer);
      if (num < data.min) return;
      if (num > data.max) return;
      *setting.value.spin = num;
    } else if (OPTION_COMBO == setting.type) {
      option_combo_setting_t data = setting.data.combo;
      for (int j = 0; j < data.count; j++) {
        if (strcmp(data.combination[i], buffer)) continue;
        *setting.value.combo = j;
      }
    } else if (OPTION_CHECK == setting.type) {
      *setting.value.check = strcmp(buffer, "true") == 0;
    } else if (OPTION_STRING == setting.type) {
      free(setting.value.string->data);
      setting.value.string->length = strlen(buffer);
      setting.value.string->data = malloc(setting.value.string->length);
      memcpy(setting.value.string->data, buffer, setting.value.string->length);
    } else if (OPTION_BUTTON == setting.type) {
      *setting.value.button = true;
    } else { assert(0); }
    return;
  }
  if (state->debug) {
    printf("debug: invalid option\n");
  }
}

// examples from uci_min.txt
// option name Nullmove type check default true\n
// option name Selectivity type spin default 2 min 0 max 4\n
// option name Style type combo default Normal var Solid var Normal var Risky\n
// option name NalimovPath type string default c:\\n
// option name Clear Hash type button\n
void print_setting(option_setting_t setting) {
  printf("option name %s type ", setting.option_name);
  // accidently did the yoda style if statement, i am keeping it
  if (OPTION_SPIN == setting.type) {
    option_spin_setting_t data = setting.data.spin;
    printf(
      "spin default %d min %d max %d\n",
      data.default_value,
      data.min,
      data.max
    );
  } else if (OPTION_COMBO == setting.type) {
    option_combo_setting_t data = setting.data.combo;
    printf("combo default %s", data.combination[data.default_index]);
    for (int i = 0; i < data.count; i++) {
      printf(" var %s", data.combination[i]);
    }
    printf("\n");
  } else if (OPTION_CHECK == setting.type) {
    printf("check default %d\n", setting.data.check_default);
  } else if (OPTION_STRING == setting.type) {
    printf("string default %s\n", setting.data.string_default);
  } else if (OPTION_BUTTON == setting.type) {
    printf("button\n");
  } else { assert(0); }
}

enum {
  STATE_INITIAL,
  STATE_IDLE,
  STATE_SYNC,
  STATE_PING,
  STATE_ACTIVE,
  STATE_HALT,
};
int current_state = STATE_INITIAL;

void handle_uci(
  uci_state *state,
  engine_messages *engine_message,
  ucicmd cmd
) {
  if (current_state == STATE_INITIAL) {
    return handle_initial(state, cmd);
  }
  if (current_state == STATE_IDLE) {
    return handle_idle(state, cmd);
  }
  if (current_state == STATE_SYNC) {
    return handle_sync(state, cmd);
  }
  if (current_state == STATE_PING) {
    return handle_ping(state, cmd);
  }
  if (current_state == STATE_ACTIVE) {
    return handle_active(state, engine_message, cmd);
  }
  return handle_halt(state, cmd);
}

void handle_initial(uci_state *state, ucicmd cmd) {
  if (cmd.empty || strcmp(cmd.root, "uci") != 0) return;
  // TIMEOUT NOTICE: THE FOLLOWING BLOCK SHOULDN'T TAKE MORE THAN 5 SECONDS
  printf("id name %s\n", state->name);
  printf("id author %s\n", state->author);
  int settings_count = sizeof(state->option_settings)/sizeof(option_setting_t);
  for (int i = 0; i < settings_count; i++) {
    print_setting(state->option_settings[i]);
  }
  // ---
  printf("uciok\n");
  current_state = STATE_IDLE;
}

void handle_idle(
  uci_state *state,
  ucicmd cmd) {
  if (cmd.empty) return;
  if (strcmp(cmd.root, "debug") == 0) {
    state->debug = strcmp(ucicmd_get_arg(cmd, 0), "on") == 0;
  } else if (strcmp(cmd.root, "setoption") == 0) {
    char buffer[2048] = {0};
    char name[64] = {0};
    char *cursor = name;
    for (int i = 1; i < cmd.args_count; i++) {
      assert((long)cursor - (long)buffer < 2048);
      char *arg = ucicmd_get_arg(cmd, i);
      if (strcmp(arg, "value") == 0) {
        *(--cursor) = 0;
        cursor = buffer;
        continue;
      }
      cursor = stpncpy(cursor, arg, MAX_TOKEN_SIZE);
      *(cursor++) = ' ';
    }
    *(--cursor) = 0;
    apply_option(state, name, buffer);
  } else if (strcmp(cmd.root, "ucinewgame") == 0) {
    if (state->moves != NULL) {
      free(state->moves);
      state->moves = NULL;
      state->moves_count = 0;
    }
  } else if (strcmp(cmd.root, "position") == 0) {
    int k = 0;
    char* mode = ucicmd_get_arg(cmd, 0);
    if (strcmp(mode, "startpos") == 0) {
      struct fen_load fen = load_fen(
        "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1"
      );
      if (fen.failed) {
        printf("info invalid fen\n");
        return;
      }
      state->position = fen.position;
    }
    else if (strcmp(mode, "fen") == 0) {
      struct fen_load fen = load_fen(ucicmd_get_arg(cmd, k++));
      if (fen.failed) {
        printf("info invalid fen\n");
        return;
      }
      state->position = fen.position;
    } else { assert(0); }

    if (cmd.args_count >= k) return;
    assert(strcmp(ucicmd_get_arg(cmd, k++), "moves") == 0);
    assert(state->moves_count <= cmd.args_count - k);
    int old_move_count = state->moves_count;
    state->moves_count = cmd.args_count - k;
    if (state->moves == NULL) {
      state->moves = malloc(
        state->moves_count * sizeof(struct uci_move)
      );
    } else {
      state->moves = realloc(
        state->moves,
        state->moves_count * sizeof(struct uci_move)
      );
    }
    int l = 0;
    k += old_move_count;
    l += old_move_count;
    for (; k < cmd.args_count; k++) {
      char* move = ucicmd_get_arg(cmd, k);
      state->moves[l++] = (struct uci_move) {
        (move[0] - 'a') * 8 + (move[1] - '1'),
        (move[2] - 'a') * 8 + (move[3] - '1')
      };
    }
  } else if (strcmp(cmd.root, "stop") == 0) {
  } else if (strcmp(cmd.root, "quit") == 0) {
    free(cmd.args);

    int settings_count = sizeof(state->option_settings)/sizeof(option_setting_t);
    for (int i = 0; i < settings_count; i++) {
      option_setting_t setting = state->option_settings[i];
      if (OPTION_STRING != setting.type) continue;
      free(setting.value.string->data);
    }

    atomic_store(&state->quit, 1);
  } else if (strcmp(cmd.root, "isready") == 0) {
    current_state = STATE_SYNC;
  } else if (strcmp(cmd.root, "go") == 0) {
    atomic_store(&state->go, 1);
    current_state = STATE_ACTIVE;
  } else {
    printf("info violation\n");
  }
}

void handle_sync(uci_state *state, ucicmd cmd) {
  // TIMEOUT NOTICE: THE FOLLOWING BLOCK SHOULDN'T TAKE MORE THAN 5 SECONDS
 


  // ---
  printf("readyok\n");
  current_state = STATE_IDLE;
}

void handle_ping(uci_state *state, ucicmd cmd) {
  // TIMEOUT NOTICE: THE FOLLOWING BLOCK SHOULDN'T TAKE MORE THAN 1 SECONDS
  
  // if (TODO) {
  //   printf("bestmove\n");
  //   current_state = STATE_IDLE;
  // }
  
  // ---
  printf("readyok\n");
  current_state = STATE_ACTIVE;
}

void handle_active(
  uci_state *state,
  engine_messages* engine_messages,
  ucicmd cmd
) {
  for (int i = 0; i < engine_messages->count; i++) {
    struct engine_message *old = engine_messages->data[i];
    if (!old->ready) continue;
    old->ready = 0;

    printf(
      "info depth %d seldepth %d multipv %d score cp %d nodes %d nps %d hashfull %d tbhits %d time %d pv",
      old->depth,
      old->seldepth,
      old->multipv,
      old->score_cp,
      old->nodes,
      old->nps,
      old->hashfull,
      old->tbhits,
      old->time
    );

    for (int j = 0; j < old->pv.count; j++) {
      struct uci_move move = old->pv.moves[i];
      printf(
        " %c%c%c%c",
        (move.from / 8) + 'a',
        (move.from % 8) + '1',
        (move.to / 8) + 'a',
        (move.to % 8) + '1'
      );
    }
    printf("\n");

    if (old->best_move.from != 0 && old->best_move.to != 0) {
      printf(
        "bestmove %c%c%c%c",
        (old->best_move.from / 8) + 'a',
        (old->best_move.from % 8) + '1',
        (old->best_move.to / 8) + 'a',
        (old->best_move.to % 8) + '1'
      );
      if (old->ponder.from != 0 && old->ponder.to != 0) {
        printf(
          " ponder %c%c%c%c",
          (old->ponder.from / 8) + 'a',
          (old->ponder.from % 8) + '1',
          (old->ponder.to / 8) + 'a',
          (old->ponder.to % 8) + '1'
        );
      }
      printf("\n");
    }

    engine_messages->data[i] = old->next;
    free(old->pv.moves);
    free(old);
  }
  // TODO: this section will call the engine to analysis
  if (cmd.empty) {
    return;
  }
  if (strcmp(cmd.root, "isready") == 0) {
    current_state = STATE_PING;
  } else if (strcmp(cmd.root, "stop") == 0) {
    current_state = STATE_HALT;
  } else {
    printf("info violation\n");
  }
}

void handle_halt(uci_state *state, ucicmd cmd) {
  // TIMEOUT NOTICE: THE FOLLOWING BLOCK SHOULDN'T TAKE MORE THAN 1 SECONDS
  
  
  // ---
  printf("bestmove 0000\n"); // TODO: idk get it rn
  current_state = STATE_IDLE;
}