<?php
declare(strict_types=1);

/**
 * ตั้งค่า AI แชท — อ่าน/เขียน Game/data/ai-settings.json
 * ใช้ session Admin หลัก (ไม่ต้องรหัส game-ai-admin แยกเมื่อเปิดจากแผง Admin)
 *
 * GET  -> { model, models[], hasKey, intent, rag_enabled, rag_context }  (ไม่ส่ง api key ดิบ)
 * PUT  -> { openai_api_key?, model?, intent?, rag_enabled?, rag_context? }
 */
require __DIR__ . '/_common.php';

require_login();
require_tab('ai-admin');

define('AI_SETTINGS_FILE', dirname(__DIR__, 2) . '/Game/data/ai-settings.json');

function ai_models(): array
{
    return [
        'gpt-5.2', 'gpt-5.2-pro', 'gpt-5.1', 'gpt-5', 'gpt-5-pro', 'gpt-5-mini', 'gpt-5-nano',
        'gpt-4.1', 'gpt-4.1-mini', 'gpt-4.1-nano',
        'o3', 'o3-mini', 'o3-pro', 'o4-mini', 'o3-deep-research', 'o4-mini-deep-research',
        'o1', 'o1-mini', 'o1-pro',
        'gpt-4o', 'gpt-4o-mini', 'gpt-4-turbo', 'gpt-4',
        'gpt-3.5-turbo',
    ];
}

function ai_defaults(): array
{
    return [
        'openai_api_key' => '',
        'model' => 'gpt-4o-mini',
        'intent' => '',
        'rag_enabled' => false,
        'rag_context' => '',
    ];
}

function ai_read(): array
{
    $base = ai_defaults();
    if (!is_file(AI_SETTINGS_FILE)) {
        return $base;
    }
    $raw = @file_get_contents(AI_SETTINGS_FILE);
    $j = json_decode($raw ?: '{}', true);
    if (!is_array($j)) {
        return $base;
    }
    return array_replace($base, array_intersect_key($j, $base));
}

function ai_write(array $s): bool
{
    $dir = dirname(AI_SETTINGS_FILE);
    if (!is_dir($dir) && !@mkdir($dir, 0755, true)) {
        return false;
    }
    $json = json_encode($s, JSON_UNESCAPED_UNICODE | JSON_PRETTY_PRINT);
    if ($json === false) {
        return false;
    }
    $tmp = AI_SETTINGS_FILE . '.tmp.' . bin2hex(random_bytes(4));
    if (file_put_contents($tmp, $json, LOCK_EX) === false) {
        return false;
    }
    if (!rename($tmp, AI_SETTINGS_FILE)) {
        @unlink($tmp);
        return false;
    }
    return true;
}

function ai_public_payload(array $s): array
{
    $key = trim((string) ($s['openai_api_key'] ?? ''));
    return [
        'ok' => true,
        'model' => (string) ($s['model'] ?? 'gpt-4o-mini') ?: 'gpt-4o-mini',
        'models' => ai_models(),
        'hasKey' => $key !== '',
        'intent' => (string) ($s['intent'] ?? ''),
        'rag_enabled' => !empty($s['rag_enabled']),
        'rag_context' => (string) ($s['rag_context'] ?? ''),
    ];
}

$method = $_SERVER['REQUEST_METHOD'] ?? 'GET';

if ($method === 'GET') {
    json_response(ai_public_payload(ai_read()));
}

if ($method === 'PUT' || $method === 'POST') {
    $body = require_json_body();
    $s = ai_read();
    if (array_key_exists('openai_api_key', $body)) {
        $s['openai_api_key'] = trim((string) $body['openai_api_key']);
    }
    if (array_key_exists('model', $body)) {
        $m = trim((string) $body['model']);
        $s['model'] = $m !== '' ? $m : 'gpt-4o-mini';
    }
    if (array_key_exists('intent', $body)) {
        $s['intent'] = (string) $body['intent'];
    }
    if (array_key_exists('rag_enabled', $body)) {
        $s['rag_enabled'] = !empty($body['rag_enabled']);
    }
    if (array_key_exists('rag_context', $body)) {
        $s['rag_context'] = (string) $body['rag_context'];
    }
    if (!ai_write($s)) {
        json_response(['ok' => false, 'error' => 'บันทึก ai-settings.json ไม่สำเร็จ'], 500);
    }
    json_response(['ok' => true]);
}

json_response(['ok' => false, 'error' => 'Method not allowed'], 405);