<?php

namespace App\Support;

use App\Models\Application;
use App\Models\Competition;

/**
 * 报名表 schema 字段与 applications 表列对齐。
 * 标量列名单从 Application::$fillable 自动派生；新增数据库列后只需加入 fillable 即可全链路生效。
 */
final class SignupApplicationFieldRegistry
{
    public const COMMITMENT_KEY = 'commitment_accepted';

    public const PROMISE_SIGNATURE_KEY = 'promise_signature';

    /** @var list<string> */
    public const FILE_FIELD_KEYS = ['plan', 'supporting'];

    /** 无专属类型约束时，标量字段允许的 schema type */
    private const GENERIC_SCALAR_TYPES = [
        'text',
        'textarea',
        'email',
        'tel',
        'select',
        'number',
        'date',
    ];

    /**
     * 可选：为常用字段收窄允许的 schema type；未列出的 fillable 列使用 GENERIC_SCALAR_TYPES。
     *
     * @var array<string, list<string>>
     */
    private const SCALAR_TYPE_HINTS = [
        'player_name' => ['text'],
        'school' => ['text'],
        'degree' => ['select'],
        'contact_email' => ['email', 'text'],
        'contact_mobile' => ['tel', 'text'],
        'company_name' => ['text'],
        'project_name' => ['text'],
        'track' => ['select'],
        'location_country' => ['select'],
        'location_province' => ['select', 'text'],
        'location_city' => ['select', 'text'],
        'oversea_country' => ['text'],
        'event_location' => ['select', 'text'],
        'team_members' => ['text', 'textarea'],
        'intro' => ['textarea', 'text'],
        'recommend' => ['text', 'textarea'],
    ];

    /**
     * @return list<string>
     */
    public static function scalarColumnKeys(): array
    {
        return Application::signupScalarFillableKeys();
    }

    /**
     * @return list<string>
     */
    public static function allSupportedFormKeys(): array
    {
        return array_values(array_unique([
            ...self::scalarColumnKeys(),
            ...self::FILE_FIELD_KEYS,
            self::COMMITMENT_KEY,
        ]));
    }

    /**
     * 供管理端报名表编辑器拉取：与后端 fillable 实时同步。
     *
     * @return array{
     *     scalar_field_keys: list<string>,
     *     file_field_keys: list<string>,
     *     commitment_field_key: string,
     *     scalar_type_hints: array<string, list<string>>,
     *     generic_scalar_types: list<string>,
     *     all_supported_form_keys: list<string>
     * }
     */
    public static function manifest(): array
    {
        $hints = [];
        foreach (self::scalarColumnKeys() as $key) {
            if (isset(self::SCALAR_TYPE_HINTS[$key])) {
                $hints[$key] = self::SCALAR_TYPE_HINTS[$key];
            }
        }

        return [
            'scalar_field_keys' => self::scalarColumnKeys(),
            'file_field_keys' => self::FILE_FIELD_KEYS,
            'commitment_field_key' => self::COMMITMENT_KEY,
            'scalar_type_hints' => $hints,
            'generic_scalar_types' => self::GENERIC_SCALAR_TYPES,
            'all_supported_form_keys' => self::allSupportedFormKeys(),
        ];
    }

    /**
     * @param  array<int, mixed>|null  $schemaJson
     * @return list<string>
     */
    public static function keysFromSchemaJson(?array $schemaJson): array
    {
        if (! is_array($schemaJson)) {
            return [];
        }

        $keys = [];
        foreach ($schemaJson as $row) {
            if (! is_array($row)) {
                continue;
            }
            $key = trim((string) ($row['key'] ?? ''));
            if ($key !== '') {
                $keys[] = $key;
            }
        }

        return array_values(array_unique($keys));
    }

    public static function schemaHasKey(Competition $competition, string $key): bool
    {
        $competition->loadMissing('formSchema');
        $rows = $competition->formSchema?->schema_json;

        return in_array($key, self::keysFromSchemaJson(is_array($rows) ? $rows : null), true);
    }

    /**
     * @return list<string>
     */
    public static function allowedTypesForScalarKey(string $key): array
    {
        return self::SCALAR_TYPE_HINTS[$key] ?? self::GENERIC_SCALAR_TYPES;
    }

    /**
     * @param  array<int, mixed>  $schemaJson
     */
    public static function validateSignupSchemaJson(array $schemaJson): ?string
    {
        $seen = [];
        $scalarKeys = array_flip(self::scalarColumnKeys());

        foreach ($schemaJson as $index => $row) {
            if (! is_array($row)) {
                return '报名表字段定义第 '.($index + 1).' 项格式无效';
            }

            $key = trim((string) ($row['key'] ?? ''));
            $type = trim((string) ($row['type'] ?? ''));
            $label = trim((string) ($row['label'] ?? ''));

            if ($key === '') {
                return '报名表存在未填写字段 key 的项（须与 applications 表列名一致）';
            }
            if ($label === '') {
                return '字段「'.$key.'」缺少显示标签';
            }
            if (isset($seen[$key])) {
                return '字段 key「'.$key.'」重复';
            }
            $seen[$key] = true;

            if ($key === self::COMMITMENT_KEY) {
                if ($type !== 'checkbox') {
                    return '参赛承诺书字段须为 checkbox 类型（key='.self::COMMITMENT_KEY.'）';
                }

                continue;
            }

            if (in_array($key, self::FILE_FIELD_KEYS, true)) {
                if ($type !== 'file') {
                    return '附件字段「'.$key.'」须为 file 类型';
                }

                continue;
            }

            if (! isset($scalarKeys[$key])) {
                if (! in_array($type, self::GENERIC_SCALAR_TYPES, true)) {
                    return '自定义字段「'.$key.'」类型须为：'.implode(' / ', self::GENERIC_SCALAR_TYPES);
                }

                continue;
            }

            $allowedTypes = self::allowedTypesForScalarKey($key);
            if ($type === '' || ! in_array($type, $allowedTypes, true)) {
                return '字段「'.$key.'」类型须为：'.implode(' / ', $allowedTypes);
            }
        }

        return null;
    }

    /**
     * @return array<string, mixed>
     */
    public static function scalarAttributesFromApplication(Application $app): array
    {
        $out = [];
        foreach (self::scalarColumnKeys() as $key) {
            $out[$key] = $app->{$key};
        }

        return $out;
    }

    /**
     * @param  array<string, mixed>  $data
     * @return array<string, mixed>
     */
    public static function filterFillableScalarData(array $data): array
    {
        $allowed = array_flip(self::scalarColumnKeys());
        $out = [];
        foreach ($data as $key => $value) {
            if (isset($allowed[$key])) {
                $out[$key] = $value;
            }
        }

        return $out;
    }

    /**
     * @param  array<string, mixed>  $data
     * @return array<string, mixed>
     */
    public static function filterAnswersJsonData(array $data): array
    {
        $columnKeys = array_flip(self::scalarColumnKeys());
        $out = [];
        foreach ($data as $key => $value) {
            if (! is_string($key) || $key === '' || isset($columnKeys[$key])) {
                continue;
            }
            if (in_array($key, self::FILE_FIELD_KEYS, true) || $key === self::COMMITMENT_KEY || $key === self::PROMISE_SIGNATURE_KEY) {
                continue;
            }
            $out[$key] = $value;
        }

        return $out;
    }
}