/*
  cttei, a TEI interface to the ct library & its computer opponent

  Copyright (C) 2021, tslil clingman

  This program is free software: you can redistribute it and/or modify
  it under the terms of the GNU General Public License as published by
  the Free Software Foundation, either version 3 of the License, or
  (at your option) any later version.

  This program is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  GNU General Public License for more details.

  You should have received a copy of the GNU General Public License
  along with this program.  If not, see <https://www.gnu.org/licenses/>.
*/

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

#include <negamax.h>
#include <tak.h>
#include <tps.h>

// Set up output function for negamax
inline void negamax_display_progress(const uint8_t cur_depth,
                                     const uint8_t init_depth,
                                     const uint32_t length) {
  (void)(cur_depth);
  (void)(init_depth);
  (void)(length);
}

enum TEI_RETURN { TEI_QUIT, TEI_OK, TEI_FAILURE };

// expects ``(startpos|tps <tps>) moves <ptn>''
static enum TEI_RETURN parse_position_string(tak_state_p state, char *line) {
  // Find the word ``moves''
  char *beg = strstr(line, "moves");

  if (!strncasecmp(line, "tps", 3)) {
    // Split the string on the space before moves
    if (beg)
      *(beg - 1) = 0;
    // so that we can load it as a TPS description
    load_tps(state, line + 4);
  } else if (!strncasecmp(line, "startpos", 8)) {
    reset_state(state, 5);
  } else {
    return TEI_FAILURE;
  }

  if (beg == NULL)
    return TEI_OK;

  // parse the PTN sequence
  strtok(beg, " ");
  char *ptn = strtok(NULL, " ");
  while (ptn != NULL) {
    if (do_ptn(state, ptn) != ACT_OK)
      return TEI_FAILURE;
    ptn = strtok(NULL, " ");
  }

  return TEI_OK;
}

static enum TEI_RETURN handle_tei(tak_state_p state, char *line) {
  if (!strcmp(line, "quit")) {
    return TEI_QUIT;
  }
  if (!strcmp(line, "isready")) {
    puts("readyok");
  } else if (!strncmp(line, "setoption Depth value ", 22)) {
    negamax_search_depth = atoi(line + 23);
  } else if (!strncmp(line, "go", 2)) {
    // TODO: for now we ignore all of the parameters
    float minimax = negamax_generate(state);
    enum ACT_RESULT r = do_ptn(state, negamax_ptn);
    if (r != ACT_OK && r != GAME_END)
      return TEI_FAILURE;
    printf("info score cp %f pv %s\nbestmove %s\n", minimax, negamax_ptn,
           negamax_ptn);
  } else if (!strncmp(line, "position", 8)) {
    return parse_position_string(state, line + 9);
  } else if (!strncmp(line, "teinewgame", 10)) {
    if (line[11] != '5')
      return TEI_FAILURE;
    const uint8_t size = atoi(line + 11);
    if (size != 5) {
      return TEI_FAILURE;
    } else {
      reset_state(state, 5);
    }
  }
  fflush(stdout);
  return TEI_OK;
}

const char *license =
    "cttei, a TEI interface to the ct library & its computer opponent\n\
\n\
Copyright (C) 2021, tslil clingman\n\
\n\
This program comes with ABSOLUTELY NO WARRANTY; and is made available under the terms of the GNU GPL v3 license. This is free software, and you are welcome to redistribute it under certain conditions; see COPYING for details.\n";

int main(int argc, char **argv) {
  (void)(argc);
  (void)(argv);

  puts(license);

  char *line = NULL;
  ssize_t read = -1;
  size_t alloc_size;

  // Wait for tei
  while ((read = getline(&line, &alloc_size, stdin))) {
    if (read > 0 && !strncmp("tei", line, 3)) {
      break;
    } else
      return EXIT_FAILURE;
  }

  if (line)
    free(line);
  line = NULL;

  // Identify ourselves, and send the options
  puts("id name cttei");
  puts("id author tslil clingman");
  puts("option name Depth type spin default 4 min 2 max 6");
  puts("teiok");
  fflush(stdout);

  // Set default option
  struct tak_state_s state_s;
  tak_state_p state = &state_s;
  negamax_search_depth = 4;
  negamax_init(5);
  reset_state(state, 5);

  for (int playing = 1; playing;) {
    if ((read = getline(&line, &alloc_size, stdin)) > 0) {
      line[read - 1] = 0;
      switch (handle_tei(state, line)) {
      case TEI_FAILURE:
        return EXIT_FAILURE;
      case TEI_QUIT:
        playing = 0; // fall-through
      case TEI_OK: {
        if (line) {
          free(line);
          line = NULL;
        }
        break;
      }
      }
    } else {
      break;
    }
  }

  if (line)
    free(line);
  negamax_free();

  return EXIT_SUCCESS;
}