/*
 * Entertain plugin — chess_cmd.c
 * /chess command handler (join/leave/list/move/resign/draw/clear/status/board).
 */
#include "entertain_chess.h"
#include "hybbx/session.h"
#include "hybbx/service.h"
#include "hybbx/command.h"

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

/* Forward declaration */
hybbx_result_t entertain_cmd_chess(struct hybbx_service *service,
                                   struct hybbx_session *session,
                                   const struct hybbx_parsed_command *cmd);

static int ieq(const char *a, const char *b)
{
    if (!a || !b) return 0;
    while (*a && *b) {
        char ca = (*a >= 'A' && *a <= 'Z') ? *a + 32 : *a;
        char cb = (*b >= 'A' && *b <= 'Z') ? *b + 32 : *b;
        if (ca != cb) return 0;
        a++; b++;
    }
    return *a == *b;
}

hybbx_result_t entertain_cmd_chess(struct hybbx_service *service,
                                   struct hybbx_session *session,
                                   const struct hybbx_parsed_command *cmd)
{
    const char *sub;
    char line[128];
    (void)service;

    if (!hybbx_session_logged_in(session)) {
        hybbx_session_write_line(session, "Log in to play chess.");
        return HYBBX_ERR_DENIED;
    }

    sub = (cmd->argc >= 1) ? cmd->argv[0] : "help";

    /* ── help ──────────────────────────────────────────────── */
    if (ieq(sub, "help") || ieq(sub, "?")) {
        hybbx_session_write_line(session, "Chess commands:");
        hybbx_session_write_line(session, "  /chess new        - Create game (you are White)");
        hybbx_session_write_line(session, "  /chess join [id]  - Join game as Black");
        hybbx_session_write_line(session, "  /chess watch [id] - Spectate");
        hybbx_session_write_line(session, "  /chess board      - Show board");
        hybbx_session_write_line(session, "  /chess move e2 e4 - Move (alias: /mv e2 e4)");
        hybbx_session_write_line(session, "  /chess resign     - Resign");
        hybbx_session_write_line(session, "  /chess draw       - Offer draw");
        hybbx_session_write_line(session, "  /chess list       - List games + boards");
        hybbx_session_write_line(session, "  /chess leave      - Stop watching");
        hybbx_session_write_line(session, "  /chess clear      - Clear game history");
        snprintf(line, sizeof(line), "Board refreshes every %ds for all.", CHESS_REFRESH_SEC);
        hybbx_session_write_line(session, line);
        return HYBBX_OK;
    }

    /* ── status ────────────────────────────────────────────── */
    if (ieq(sub, "status")) {
        snprintf(line, sizeof(line), "Chess: %u max games", chess_max_games());
        hybbx_session_write_line(session, line);
        return HYBBX_OK;
    }

    /* ── list ──────────────────────────────────────────────── */
    if (ieq(sub, "list") || ieq(sub, "ls")) {
        unsigned found = 0;
        hybbx_session_write_line(session, "Chess games:");
        for (unsigned i = 0; i < chess_max_games(); i++) {
            chess_game_t *g = chess_get_game(i);
            if (!g) continue;
            const char *st = (g->result != CHESS_RESULT_NONE) ? "finished" :
                             (!g->black_session) ? "waiting" : "playing";
            snprintf(line, sizeof(line), "  [%s] %s(W) vs %s(B)  %s  move %u",
                     g->game_id, g->white_name,
                     g->black_session ? g->black_name : "...",
                     st, g->move_number);
            hybbx_session_write_line(session, line);
            chess_send_board(g, session);
            if (g->spectator_count > 0) {
                int n = snprintf(line, sizeof(line), "  Spectators (%u): ", g->spectator_count);
                for (unsigned j = 0; j < g->spectator_count; j++) {
                    const char *nm = hybbx_session_display_name(g->spectators[j]);
                    if (j > 0) n += snprintf(line+n, sizeof(line)-(size_t)n, ", ");
                    n += snprintf(line+n, sizeof(line)-(size_t)n, "%s", nm ? nm : "?");
                }
                hybbx_session_write_line(session, line);
            }
            hybbx_session_write_line(session, "");
            found++;
        }
        if (!found) hybbx_session_write_line(session, "  No active games.");
        return HYBBX_OK;
    }

    /* ── new ───────────────────────────────────────────────── */
    if (ieq(sub, "new") || ieq(sub, "create")) {
        for (unsigned i = 0; i < chess_max_games(); i++) {
            chess_game_t *g = chess_get_game(i);
            if (g && chess_is_player(g, session)) {
                hybbx_session_write_line(session, "Already in a game. /chess resign first.");
                return HYBBX_ERR_DENIED;
            }
        }
        chess_game_t *g = chess_create_game(session, hybbx_session_username(session));
        if (!g) { hybbx_session_write_line(session, "No free game slots."); return HYBBX_ERR_DENIED; }
        snprintf(line, sizeof(line), "Game %s created. You are White.", g->game_id);
        hybbx_session_write_line(session, line);
        hybbx_session_write_line(session, "Waiting for Black to /chess join...");
        chess_send_board(g, session);
        return HYBBX_OK;
    }

    /* ── join ──────────────────────────────────────────────── */
    if (ieq(sub, "join")) {
        const char *id = (cmd->argc >= 2) ? cmd->argv[1] : NULL;
        for (unsigned i = 0; i < chess_max_games(); i++) {
            chess_game_t *g = chess_get_game(i);
            if (g && chess_is_player(g, session)) {
                hybbx_session_write_line(session, "Already in a game. /chess resign first.");
                return HYBBX_ERR_DENIED;
            }
        }
        chess_game_t *g = NULL;
        if (id) {
            g = chess_find_game_by_id(id);
            if (!g || !g->active) { hybbx_session_write_line(session, "Game not found."); return HYBBX_ERR_NOT_FOUND; }
            if (g->black_session) { hybbx_session_write_line(session, "Game is full."); return HYBBX_ERR_DENIED; }
        } else {
            g = chess_find_open_game();
            if (!g) { hybbx_session_write_line(session, "No open games. /chess new"); return HYBBX_ERR_NOT_FOUND; }
        }
        chess_join_game(g, session, hybbx_session_username(session));
        snprintf(line, sizeof(line), "Joined %s as Black. Game on!", g->game_id);
        hybbx_session_write_line(session, line);
        chess_send_board(g, g->white_session);
        chess_send_board(g, session);
        return HYBBX_OK;
    }

    /* ── watch ─────────────────────────────────────────────── */
    if (ieq(sub, "watch") || ieq(sub, "spectate")) {
        const char *id = (cmd->argc >= 2) ? cmd->argv[1] : NULL;
        chess_game_t *g = NULL;
        if (id) {
            g = chess_find_game_by_id(id);
        } else {
            for (unsigned i = 0; i < chess_max_games(); i++) {
                chess_game_t *t = chess_get_game(i);
                if (t && t->black_session) { g = t; break; }
            }
        }
        if (!g || !g->active) { hybbx_session_write_line(session, "No game to watch."); return HYBBX_ERR_NOT_FOUND; }
        if (!chess_add_spectator(g, session)) { hybbx_session_write_line(session, "Spectator list full."); return HYBBX_ERR_DENIED; }
        snprintf(line, sizeof(line), "Watching %s. Board refreshes every %ds.", g->game_id, CHESS_REFRESH_SEC);
        hybbx_session_write_line(session, line);
        chess_send_board(g, session);
        return HYBBX_OK;
    }

    /* ── leave ─────────────────────────────────────────────── */
    if (ieq(sub, "leave") || ieq(sub, "unwatch")) {
        for (unsigned i = 0; i < chess_max_games(); i++) {
            chess_game_t *g = chess_get_game(i);
            if (g && chess_is_spectator(g, session)) {
                chess_remove_spectator(g, session);
                hybbx_session_write_line(session, "Stopped watching.");
                return HYBBX_OK;
            }
        }
        hybbx_session_write_line(session, "Not watching any game.");
        return HYBBX_ERR_NOT_FOUND;
    }

    /* ── board ─────────────────────────────────────────────── */
    if (ieq(sub, "board") || ieq(sub, "show")) {
        for (unsigned i = 0; i < chess_max_games(); i++) {
            chess_game_t *g = chess_get_game(i);
            if (g && (chess_is_player(g, session) || chess_is_spectator(g, session))) {
                chess_send_board(g, session);
                return HYBBX_OK;
            }
        }
        hybbx_session_write_line(session, "Not in a game. /chess new, join, or watch.");
        return HYBBX_ERR_NOT_FOUND;
    }

    /* ── move ──────────────────────────────────────────────── */
    if (ieq(sub, "move") || ieq(sub, "mv") || ieq(sub, "m")) {
        if (cmd->argc < 3) { hybbx_session_write_line(session, "Usage: /chess move e2 e4"); return HYBBX_ERR_INVALID; }
        chess_game_t *game = NULL;
        for (unsigned i = 0; i < chess_max_games(); i++) {
            chess_game_t *g = chess_get_game(i);
            if (g && g->result == CHESS_RESULT_NONE && chess_is_player(g, session)) {
                if (chess_player_color(g, session) == g->turn) { game = g; break; }
            }
        }
        if (!game) { hybbx_session_write_line(session, "Not your turn or no active game."); return HYBBX_ERR_DENIED; }
        char err[64];
        if (!chess_make_move(game, cmd->argv[1], cmd->argv[2], 0, err, sizeof(err))) {
            snprintf(line, sizeof(line), "Illegal: %s", err);
            hybbx_session_write_line(session, line);
            return HYBBX_ERR_INVALID;
        }
        /* Broadcast to all */
        if (game->white_session)  chess_send_board(game, game->white_session);
        if (game->black_session)  chess_send_board(game, game->black_session);
        for (unsigned j = 0; j < game->spectator_count; j++)
            chess_send_board(game, game->spectators[j]);
        /* Game over? */
        if (game->result != CHESS_RESULT_NONE) {
            const char *res;
            switch (game->result) {
            case CHESS_WHITE_WINS:     res = "White wins!"; break;
            case CHESS_BLACK_WINS:     res = "Black wins!"; break;
            case CHESS_DRAW_STALEMATE: res = "Stalemate!"; break;
            case CHESS_DRAW_AGREEMENT: res = "Draw!"; break;
            default:                   res = "Game over."; break;
            }
            snprintf(line, sizeof(line), "[%s] %s", game->game_id, res);
            if (game->white_session)  hybbx_session_write_line(game->white_session, line);
            if (game->black_session)  hybbx_session_write_line(game->black_session, line);
            for (unsigned j = 0; j < game->spectator_count; j++)
                hybbx_session_write_line(game->spectators[j], line);
        }
        return HYBBX_OK;
    }

    /* ── resign ────────────────────────────────────────────── */
    if (ieq(sub, "resign")) {
        chess_game_t *game = NULL;
        for (unsigned i = 0; i < chess_max_games(); i++) {
            chess_game_t *g = chess_get_game(i);
            if (g && chess_is_player(g, session)) { game = g; break; }
        }
        if (!game) { hybbx_session_write_line(session, "Not in a game."); return HYBBX_ERR_NOT_FOUND; }
        chess_resign(game, session);
        snprintf(line, sizeof(line), "[%s] %s resigned.", game->game_id, hybbx_session_username(session));
        if (game->white_session)  hybbx_session_write_line(game->white_session, line);
        if (game->black_session)  hybbx_session_write_line(game->black_session, line);
        for (unsigned j = 0; j < game->spectator_count; j++)
            hybbx_session_write_line(game->spectators[j], line);
        return HYBBX_OK;
    }

    /* ── draw ──────────────────────────────────────────────── */
    if (ieq(sub, "draw")) {
        chess_game_t *game = NULL;
        for (unsigned i = 0; i < chess_max_games(); i++) {
            chess_game_t *g = chess_get_game(i);
            if (g && chess_is_player(g, session)) { game = g; break; }
        }
        if (!game) { hybbx_session_write_line(session, "Not in a game."); return HYBBX_ERR_NOT_FOUND; }
        chess_offer_draw(game, session);
        snprintf(line, sizeof(line), "[%s] Draw agreed.", game->game_id);
        if (game->white_session)  hybbx_session_write_line(game->white_session, line);
        if (game->black_session)  hybbx_session_write_line(game->black_session, line);
        for (unsigned j = 0; j < game->spectator_count; j++)
            hybbx_session_write_line(game->spectators[j], line);
        return HYBBX_OK;
    }

    /* ── clear ─────────────────────────────────────────────── */
    if (ieq(sub, "clear") || ieq(sub, "reset")) {
        hybbx_session_write_line(session, "Chess has no persistent history to clear.");
        return HYBBX_OK;
    }

    hybbx_session_write_line(session, "Unknown chess command. /chess help");
    return HYBBX_ERR_NOT_FOUND;
}