<?php

namespace App\Services;

use App\Support\MaintenancePolicy as Policy;
use Carbon\Carbon;
use DateTimeImmutable;
use DateTimeZone;
use Illuminate\Support\Facades\DB;
use Illuminate\Support\Facades\Validator;
use Illuminate\Validation\Rule;
use Illuminate\Validation\ValidationException;

class MaintenanceService
{
    public function options(): array
    {
        $options = static fn ($map) => array_map(static fn ($value, $label) => compact('value', 'label'), array_keys($map), array_values($map));
        return ['scopes' => $options(Policy::scopes()), 'categories' => $options(Policy::CATEGORIES),
            'platforms' => $options(['PC' => 'PC', 'H5' => 'H5', 'APP' => 'APP']), 'languages' => $options(Policy::LANGUAGES),
            'states' => $options(Policy::STATES), 'timezones' => DateTimeZone::listIdentifiers(),
            'defaults' => ['enabled' => 0, 'platforms' => ['PC', 'H5', 'APP'], 'timezone' => 'Asia/Shanghai', 'ends_at' => null],
            'business_codes' => ['site' => Policy::SITE_CODE, 'game' => Policy::GAME_CODE]];
    }

    public function listing(array $input): array
    {
        $params = Validator::make($input, [
            'page' => ['nullable', 'integer', 'min:1', 'max:1000000'], 'limit' => ['nullable', 'integer', 'min:1', 'max:100'],
            'scope_code' => ['nullable', Rule::in(array_keys(Policy::scopes()))], 'platform' => ['nullable', Rule::in(['PC', 'H5', 'APP'])],
            'enabled' => ['nullable', 'integer', 'in:0,1'], 'state' => ['nullable', Rule::in(array_keys(Policy::STATES))],
            'language' => ['nullable', Rule::in(array_keys(Policy::LANGUAGES))],
        ])->validate();
        $texts = [];
        foreach (DB::table('maintenance_translations')->get() as $text) $texts[$text->maintenance_id][$text->language] = ['content' => $text->content];
        $rows = [];
        foreach (DB::table('maintenance_settings')->orderBy('id')->get() as $record) {
            $row = $this->dto((array) $record, $texts[$record->id] ?? []);
            if (!empty($params['scope_code']) && $row['scope_code'] !== $params['scope_code']) continue;
            if (!empty($params['platform']) && !in_array($params['platform'], $row['platforms'], true)) continue;
            if (isset($params['enabled']) && $row['enabled'] !== (int) $params['enabled']) continue;
            if (!empty($params['state']) && $row['state'] !== $params['state']) continue;
            if (!empty($params['language']) && !isset($texts[$record->id][$params['language']])) continue;
            $rows[] = $row;
        }
        return ['total' => count($rows), 'data' => array_slice($rows, ((int) ($params['page'] ?? 1) - 1) * (int) ($params['limit'] ?? 20), (int) ($params['limit'] ?? 20))];
    }

    public function detail(int $id): array
    {
        $row = DB::table('maintenance_settings')->where('id', $id)->first();
        if (!$row) $this->invalid('id', '维护设置不存在');
        return $this->dto((array) $row, $this->texts($id));
    }

    public function save(array $input): array
    {
        $params = Validator::make($input, [
            'id' => ['required', 'integer', 'min:1'], 'scope_code' => ['prohibited'],
            'platforms' => ['sometimes', 'required', 'array', 'min:1', 'max:3'],
            'platforms.*' => ['required', 'distinct', Rule::in(['PC', 'H5', 'APP'])],
            'enabled' => ['sometimes', 'required', 'integer', 'in:0,1'], 'start_now' => ['sometimes', 'boolean'],
            'starts_at' => ['sometimes', 'required', 'date_format:Y-m-d H:i:s'], 'ends_at' => ['nullable', 'date_format:Y-m-d H:i:s'],
            'timezone' => ['sometimes', 'required', 'string', Rule::in(DateTimeZone::listIdentifiers())],
            'translations' => ['sometimes', 'array'],
        ])->validate();
        return DB::transaction(function () use ($params) {
            $id = (int) $params['id'];
            $found = DB::table('maintenance_settings')->where('id', $id)->lockForUpdate()->first();
            if (!$found) $this->invalid('id', '维护设置不存在');
            $before = $this->snapshot($id); $row = (array) $found;
            foreach (['enabled', 'timezone', 'platforms'] as $field) if (array_key_exists($field, $params)) $row[$field] = $params[$field];
            $row['platforms'] = array_values(array_intersect(['PC', 'H5', 'APP'], Policy::platforms($row)));
            if (!empty($params['start_now'])) $row['starts_at'] = $this->now()->format('Y-m-d H:i:s');
            elseif (isset($params['starts_at'])) $row['starts_at'] = $this->utc($params['starts_at'], $row['timezone'], 'starts_at');
            if (array_key_exists('ends_at', $params)) $row['ends_at'] = $params['ends_at'] === null ? null : $this->utc($params['ends_at'], $row['timezone'], 'ends_at');
            if ($row['ends_at'] !== null && $row['ends_at'] <= $row['starts_at']) $this->invalid('ends_at', '结束时间必须晚于开始时间');
            $texts = $before['translations'];
            foreach ($texts as &$text) unset($text['title']); unset($text);
            if (array_key_exists('translations', $params)) {
                if (array_diff(array_keys($params['translations']), array_keys(Policy::LANGUAGES))) $this->invalid('translations', '仅支持zh/en/vi');
                $texts = [];
                foreach ($params['translations'] as $language => $text) {
                    if (!is_array($text)) $this->invalid('translations', '语言内容必须为对象');
                    $value = Validator::make($text, ['content' => ['nullable', 'string', 'max:5000']])->validate();
                    if (trim((string) ($value['content'] ?? '')) !== '') $texts[$language] = ['content' => $value['content']];
                }
            }
            $values = array_intersect_key($row, array_flip(['enabled', 'timezone', 'platforms', 'starts_at', 'ends_at']));
            $values['enabled'] = (int) $values['enabled']; $values['platforms'] = json_encode($values['platforms'], JSON_THROW_ON_ERROR);
            $values['updated_at'] = $this->now()->format('Y-m-d H:i:s');
            DB::table('maintenance_settings')->where('id', $id)->update($values);
            if (array_key_exists('translations', $params)) {
                DB::table('maintenance_translations')->where('maintenance_id', $id)->delete();
                foreach ($texts as $language => $text) DB::table('maintenance_translations')->insert(['maintenance_id' => $id, 'language' => $language, 'content' => $text['content']]);
            }
            $after = $this->snapshot($id);
            if ($before !== $after) {
                OperationAuditService::record('maintenance', $id, 'update', $before, $after, $this->now()->setTimezone('Asia/Shanghai')->format('Y-m-d H:i:s'));
                $local = static fn ($at) => $at === null ? null : Carbon::parse($at, 'UTC')->setTimezone('Asia/Shanghai')->format('Y-m-d H:i:s');
                SiteRealtimeService::changed('maintenance', $id, 'update',
                    $after['enabled'] ? ['start' => $local($after['starts_at']), 'end' => $local($after['ends_at'])] : []);
            }
            return $this->detail($id);
        });
    }

    public function status(int $id, int $enabled): array { return $this->save(compact('id', 'enabled')); }

    public function logs(array $input): array { return LocalizedAuditService::listing('maintenance', $input); }

    public function runtimeRows(string $language): array
    {
        return DB::table('maintenance_settings as m')->leftJoin('maintenance_translations as t', function ($join) use ($language) {
            $join->on('t.maintenance_id', '=', 'm.id')->where('t.language', $language);
        })->where('m.enabled', 1)->select('m.*', 't.content')->get()->map(fn ($row) => (array) $row)->all();
    }

    private function dto(array $row, array $texts): array
    {
        $public = Policy::publicRule($row, 'zh'); unset($public['language'], $public['content']);
        return ['id' => (int) $row['id'], 'scope_code' => $row['scope_code'], 'scope_name' => Policy::scopes()[$row['scope_code']],
            'enabled' => (int) $row['enabled'], 'state' => Policy::state($row, $this->now()->getTimestamp()),
            'translations' => (object) $texts] + $public;
    }

    private function texts(int $id): array
    {
        $texts = [];
        foreach (DB::table('maintenance_translations')->where('maintenance_id', $id)->orderBy('language')->get() as $text) $texts[$text->language] = ['content' => $text->content];
        return $texts;
    }

    private function snapshot(int $id): array
    {
        $row = (array) DB::table('maintenance_settings')->where('id', $id)->first();
        unset($row['created_at'], $row['updated_at']); $row['enabled'] = (int) $row['enabled']; $row['platforms'] = Policy::platforms($row);
        $row['translations'] = $this->texts($id);
        foreach ($row['translations'] as &$text) $text['title'] = Policy::scopes()[$row['scope_code']];
        return $row;
    }

    private function utc(string $value, string $timezone, string $field): string
    {
        $date = DateTimeImmutable::createFromFormat('!Y-m-d H:i:s', $value, new DateTimeZone($timezone));
        if (!$date || $date->format('Y-m-d H:i:s') !== $value) $this->invalid($field, '该时区中不存在此时间');
        // Repeated local wall times during DST transitions require a different, unambiguous time.
        $utc = $date->getTimestamp();
        foreach ([-7200, -3600, -1800, 1800, 3600, 7200] as $offset) {
            if ($date->setTimestamp($utc + $offset)->format('Y-m-d H:i:s') === $value) $this->invalid($field, '该时区中此时间存在夏令时歧义，请选择其他时间');
        }
        return $date->setTimezone(new DateTimeZone('UTC'))->format('Y-m-d H:i:s');
    }

    private function now(): Carbon { return Carbon::now('UTC'); }
    private function invalid(string $field, string $message): void { throw ValidationException::withMessages([$field => $message]); }
}