<?php

namespace App\Http\Controllers\Admin;

use App\Http\Controllers\Controller;
use App\Models\Activity;
use App\Models\Banner;
use App\Models\Course;
use App\Models\News;
use App\Support\ApiResponse;
use Illuminate\Http\JsonResponse;
use Illuminate\Http\Request;
use Illuminate\Validation\Rule;
use Illuminate\Validation\ValidationException;

class BannerController extends Controller
{
    use ApiResponse;

    public function index(Request $request): JsonResponse
    {
        $query = Banner::query()->with(['course', 'activity', 'news']);

        if ($request->filled('type')) {
            $query->where('type', $request->query('type'));
        }
        if ($request->filled('status')) {
            $query->where('status', (int) $request->query('status'));
        }
        if ($kw = $request->query('keyword')) {
            $query->where(function ($q) use ($kw) {
                $q->where('title', 'like', "%{$kw}%")
                    ->orWhereHas('course', fn ($cq) => $cq->where('title', 'like', "%{$kw}%"))
                    ->orWhereHas('activity', fn ($aq) => $aq->where('title', 'like', "%{$kw}%"))
                    ->orWhereHas('news', fn ($nq) => $nq->where('title', 'like', "%{$kw}%"));
            });
        }

        $paginator = $query
            ->orderBy('sort')
            ->orderByDesc('id')
            ->paginate((int) $request->query('page_size', 20))
            ->withQueryString();

        $paginator->getCollection()->transform(fn (Banner $b) => $this->serialize($b));

        return $this->paginated($paginator);
    }

    public function show(int $banner): JsonResponse
    {
        $model = Banner::query()->with(['course', 'activity', 'news'])->findOrFail($banner);

        return $this->ok($this->serialize($model));
    }

    public function store(Request $request): JsonResponse
    {
        $data = $this->validatedBanner($request);
        $row = Banner::query()->create($data);

        return $this->ok(['id' => $row->id], '已创建');
    }

    public function update(Request $request, int $banner): JsonResponse
    {
        $model = Banner::query()->findOrFail($banner);
        $data = $this->validatedBanner($request, $model);
        $model->fill($data);
        $model->save();

        return $this->ok($this->serialize($model->fresh(['course', 'activity', 'news'])), '已保存');
    }

    public function destroy(int $banner): JsonResponse
    {
        Banner::query()->findOrFail($banner)->delete();

        return $this->ok(null, '已删除');
    }

    /**
     * @return array<string, mixed>
     */
    protected function validatedBanner(Request $request, ?Banner $existing = null): array
    {
        $base = $request->validate([
            'type' => array_merge(
                [$existing ? 'sometimes' : 'required', 'string'],
                [Rule::in([Banner::TYPE_COURSE, Banner::TYPE_ACTIVITY, Banner::TYPE_NEWS, Banner::TYPE_CUSTOM])]
            ),
            'course_id' => ['nullable', 'integer', 'exists:courses,id'],
            'activity_id' => ['nullable', 'integer', 'exists:activities,id'],
            'news_id' => ['nullable', 'integer', 'exists:news,id'],
            'title' => ['nullable', 'string', 'max:255'],
            'cover_url' => ['nullable', 'string', 'max:512'],
            'content_html' => ['nullable', 'string'],
            'sort' => [$existing ? 'sometimes' : 'required', 'integer', 'min:0'],
            'status' => ['sometimes', 'integer', 'in:0,1'],
        ]);

        $type = $base['type'] ?? $existing?->type;
        if (! $type) {
            throw ValidationException::withMessages(['type' => ['请选择 Banner 类型']]);
        }

        $payload = [
            'type' => $type,
            'course_id' => null,
            'activity_id' => null,
            'news_id' => null,
            'title' => null,
            'cover_url' => null,
            'content_html' => null,
            'sort' => isset($base['sort']) ? (int) $base['sort'] : ($existing?->sort ?? 0),
            'status' => isset($base['status']) ? (int) $base['status'] : ($existing?->status ?? 1),
        ];

        match ($type) {
            Banner::TYPE_COURSE => $this->fillCourse($payload, $base, $existing),
            Banner::TYPE_ACTIVITY => $this->fillActivity($payload, $base, $existing),
            Banner::TYPE_NEWS => $this->fillNews($payload, $base, $existing),
            Banner::TYPE_CUSTOM => $this->fillCustom($payload, $base, $existing),
        };

        return $payload;
    }

    /**
     * @param  array<string, mixed>  $payload
     * @param  array<string, mixed>  $data
     */
    protected function fillCourse(array &$payload, array $data, ?Banner $existing): void
    {
        $courseId = $data['course_id'] ?? $existing?->course_id;
        if (! $courseId) {
            throw ValidationException::withMessages(['course_id' => ['请选择课程']]);
        }
        if (! Course::query()->whereKey($courseId)->exists()) {
            throw ValidationException::withMessages(['course_id' => ['所选课程不存在']]);
        }
        $payload['course_id'] = (int) $courseId;
    }

    /**
     * @param  array<string, mixed>  $payload
     * @param  array<string, mixed>  $data
     */
    protected function fillActivity(array &$payload, array $data, ?Banner $existing): void
    {
        $activityId = $data['activity_id'] ?? $existing?->activity_id;
        if (! $activityId) {
            throw ValidationException::withMessages(['activity_id' => ['请选择活动']]);
        }
        if (! Activity::query()->whereKey($activityId)->exists()) {
            throw ValidationException::withMessages(['activity_id' => ['所选活动不存在']]);
        }
        $payload['activity_id'] = (int) $activityId;
    }

    /**
     * @param  array<string, mixed>  $payload
     * @param  array<string, mixed>  $data
     */
    protected function fillNews(array &$payload, array $data, ?Banner $existing): void
    {
        $newsId = $data['news_id'] ?? $existing?->news_id;
        if (! $newsId) {
            throw ValidationException::withMessages(['news_id' => ['请选择资讯']]);
        }
        $news = News::query()->whereKey($newsId)->first();
        if (! $news) {
            throw ValidationException::withMessages(['news_id' => ['所选资讯不存在']]);
        }
        if ((int) $news->status !== 1) {
            throw ValidationException::withMessages(['news_id' => ['只能选择已发布的资讯']]);
        }
        $payload['news_id'] = (int) $newsId;
    }

    /**
     * @param  array<string, mixed>  $payload
     * @param  array<string, mixed>  $data
     */
    protected function fillCustom(array &$payload, array $data, ?Banner $existing): void
    {
        $title = array_key_exists('title', $data)
            ? trim((string) $data['title'])
            : ($existing?->title ?? '');
        $cover = array_key_exists('cover_url', $data)
            ? trim((string) $data['cover_url'])
            : ($existing?->cover_url ?? '');
        $content = array_key_exists('content_html', $data)
            ? (string) $data['content_html']
            : ($existing?->content_html ?? '');

        if ($title === '') {
            throw ValidationException::withMessages(['title' => ['请填写标题']]);
        }
        if ($cover === '') {
            throw ValidationException::withMessages(['cover_url' => ['请上传封面图']]);
        }

        $payload['title'] = $title;
        $payload['cover_url'] = $cover;
        $payload['content_html'] = trim(strip_tags($content)) === '' ? null : $content;
    }

    /**
     * @return array<string, mixed>
     */
    protected function serialize(Banner $b): array
    {
        $summary = match ($b->type) {
            Banner::TYPE_COURSE => $b->course?->title,
            Banner::TYPE_ACTIVITY => $b->activity?->title,
            Banner::TYPE_NEWS => $b->news?->title,
            Banner::TYPE_CUSTOM => $b->title,
            default => null,
        };

        return [
            'id' => $b->id,
            'type' => $b->type,
            'type_label' => Banner::typeLabel($b->type),
            'course_id' => $b->course_id,
            'course_title' => $b->course?->title,
            'activity_id' => $b->activity_id,
            'activity_title' => $b->activity?->title,
            'news_id' => $b->news_id,
            'news_title' => $b->news?->title,
            'title' => $b->title,
            'cover_url' => $b->cover_url,
            'content_html' => $b->content_html,
            'summary' => $summary,
            'sort' => (int) $b->sort,
            'status' => (int) $b->status,
            'created_at' => $b->created_at?->toIso8601String(),
            'updated_at' => $b->updated_at?->toIso8601String(),
        ];
    }
}