<?php

namespace App\Http\Controllers\Business;

use App\Business\SystemizationTodoWorkbookImporter;
use App\Models\Business\SystemizationTodo;
use App\Models\Business\SystemizationTodoAttachment;
use Illuminate\Http\RedirectResponse;
use Illuminate\Http\Request;
use Illuminate\Routing\Controller;
use Illuminate\Support\Collection;
use Illuminate\Support\Facades\Storage;
use Illuminate\Support\Str;
use Illuminate\Validation\Rule;
use Symfony\Component\HttpFoundation\StreamedResponse;
use Throwable;

class SystemizationTodos extends Controller
{
    private const OVERDUE_FILTER = '__overdue__';

    public function page(): array
    {
        $filters = $this->filters();
        $query = SystemizationTodo::query()
            ->with('attachments')
            ->withCount('attachments');

        if ($filters['status'] === self::OVERDUE_FILTER) {
            $query->whereNotIn('status', [SystemizationTodo::STATUS_COMPLETED])
                ->whereNotNull('due_date')
                ->whereDate('due_date', '<', today());
        } elseif ($filters['status'] !== '') {
            $query->where('status', $filters['status']);
        }
        if ($filters['category'] !== '') {
            $query->where('category', $filters['category']);
        }
        if ($filters['owners'] !== []) {
            $query->where(function ($builder) use ($filters): void {
                foreach ($filters['owners'] as $owner) {
                    $builder->orWhere(
                        'owner',
                        'like',
                        '%' . addcslashes($owner, '%_\\') . '%',
                    );
                }
            });
        }
        if ($filters['assignees'] !== []) {
            $query->where(function ($builder) use ($filters): void {
                foreach ($filters['assignees'] as $assignee) {
                    $builder->orWhere(
                        'assignee',
                        'like',
                        '%' . addcslashes($assignee, '%_\\') . '%',
                    );
                }
            });
        }
        if ($filters['start_date'] !== '') {
            $query->whereDate('start_date', $filters['start_date']);
        }
        if ($filters['due_date'] !== '') {
            $query->whereDate('due_date', $filters['due_date']);
        }
        if ($filters['keyword'] !== '') {
            $like = '%' . addcslashes($filters['keyword'], '%_\\') . '%';
            $query->where(function ($builder) use ($like): void {
                $builder->where('title', 'like', $like)
                    ->orWhere('category', 'like', $like)
                    ->orWhere('section', 'like', $like)
                    ->orWhere('owner', 'like', $like)
                    ->orWhere('assignee', 'like', $like)
                    ->orWhere('progress', 'like', $like)
                    ->orWhere('notes', 'like', $like);
            });
        }

        $items = $query
            ->select($query->qualifyColumn('*'))
            ->selectRaw(
                "ROW_NUMBER() OVER (
                    PARTITION BY COALESCE(NULLIF(category, ''), '__uncategorized__')
                    ORDER BY
                        CASE WHEN status = '已完成' THEN 1 ELSE 0 END,
                        CASE WHEN section IS NULL OR section = '' THEN 1 ELSE 0 END,
                        section,
                        CASE WHEN due_date IS NULL THEN 1 ELSE 0 END,
                        due_date,
                        sort_order,
                        id
                ) AS category_sequence"
            )
            ->orderByRaw("CASE WHEN status = '已完成' THEN 1 ELSE 0 END")
            ->orderByRaw("CASE WHEN category IS NULL OR category = '' THEN 1 ELSE 0 END")
            ->orderBy('category')
            ->orderByRaw("CASE WHEN section IS NULL OR section = '' THEN 1 ELSE 0 END")
            ->orderBy('section')
            ->orderByRaw('CASE WHEN due_date IS NULL THEN 1 ELSE 0 END')
            ->orderBy('due_date')
            ->orderBy('sort_order')
            ->orderBy('id')
            ->paginate(50)
            ->withQueryString();

        $base = SystemizationTodo::query();
        $categories = SystemizationTodo::query()
            ->whereNotNull('category')
            ->where('category', '<>', '')
            ->distinct()
            ->orderBy('category')
            ->pluck('category');
        $statusCounts = (clone $base)
            ->selectRaw('status, COUNT(*) AS aggregate')
            ->groupBy('status')
            ->pluck('aggregate', 'status');
        $overdueCount = (clone $base)
            ->whereNotIn('status', [SystemizationTodo::STATUS_COMPLETED])
            ->whereNotNull('due_date')
            ->whereDate('due_date', '<', today())
            ->count();
        $statusOptions = collect();
        if ($overdueCount > 0) {
            $statusOptions->push([
                'value' => self::OVERDUE_FILTER,
                'label' => '已逾期',
            ]);
        }
        foreach (SystemizationTodo::STATUSES as $status) {
            if ((int) $statusCounts->get($status, 0) > 0) {
                $statusOptions->push([
                    'value' => $status,
                    'label' => $status,
                ]);
            }
        }

        return [
            'view' => 'business.pages.systemization-todos',
            'title' => '系统化待办',
            'items' => $items,
            'todoFilters' => $filters,
            'todoCategories' => $categories,
            'todoOwners' => $this->peopleOptions('owner'),
            'todoAssignees' => $this->peopleOptions('assignee'),
            'todoStatuses' => SystemizationTodo::STATUSES,
            'todoStatusOptions' => $statusOptions,
            'todoSummary' => [
                'total' => (clone $base)->count(),
                'pending' => (int) $statusCounts->get(SystemizationTodo::STATUS_PENDING, 0),
                'in_progress' => (int) $statusCounts->get(SystemizationTodo::STATUS_IN_PROGRESS, 0),
                'completed' => (int) $statusCounts->get(SystemizationTodo::STATUS_COMPLETED, 0),
                'overdue' => $overdueCount,
            ],
            'todoRoutes' => [
                'store' => route('business.systemization-todos.store'),
                'update' => route('business.systemization-todos.update', ['todo' => '__TODO__']),
                'destroy' => route('business.systemization-todos.destroy', ['todo' => '__TODO__']),
                'attachment' => route('business.systemization-todos.attachments.show', [
                    'todo' => '__TODO__',
                    'attachment' => '__ATTACHMENT__',
                ]),
                'import' => route('business.systemization-todos.import'),
            ],
        ];
    }

    public function store(Request $request): RedirectResponse
    {
        $data = $this->validated($request);
        $data['company_id'] = (int) company_id();
        $data['sort_order'] = (int) SystemizationTodo::query()->max('sort_order') + 1;
        $data['created_by'] = user_id();
        $data['updated_by'] = user_id();
        $this->normalizeCompletionDates($data);
        $todo = SystemizationTodo::query()->create($data);
        $this->storeAttachments($request, $todo);

        return $this->backToPage('待办事项已新增。');
    }

    public function update(Request $request, SystemizationTodo $todo): RedirectResponse
    {
        $data = $this->validated($request);
        $data['updated_by'] = user_id();
        $this->normalizeCompletionDates($data);

        $removeIds = collect($request->input('remove_attachments', []))
            ->map(static fn (mixed $id): int => (int) $id)
            ->filter()
            ->unique()
            ->values();
        if ($removeIds->isNotEmpty()) {
            $attachments = $todo->attachments()
                ->where('company_id', (int) company_id())
                ->whereIn('id', $removeIds)
                ->get();
            foreach ($attachments as $attachment) {
                Storage::disk('uploads')->delete($attachment->path);
                $attachment->delete();
            }
        }

        $todo->update($data);
        $this->storeAttachments($request, $todo);

        return $this->backToPage('待办事项已更新。');
    }

    public function destroy(SystemizationTodo $todo): RedirectResponse
    {
        $todo->update(['updated_by' => user_id()]);
        $todo->delete();

        return $this->backToPage('待办事项已删除。');
    }

    public function attachment(SystemizationTodo $todo, SystemizationTodoAttachment $attachment): StreamedResponse
    {
        abort_unless((int) $attachment->systemization_todo_id === (int) $todo->id, 404);
        abort_unless((int) $attachment->company_id === (int) company_id(), 404);

        $disk = Storage::disk('uploads');
        abort_unless($disk->exists($attachment->path), 404, '截图不存在。');

        return $disk->response($attachment->path, $attachment->original_name, [
            'Cache-Control' => 'private, no-store',
            'Content-Type' => $attachment->mime_type,
            'X-Content-Type-Options' => 'nosniff',
        ]);
    }

    public function importWorkbook(
        Request $request,
        SystemizationTodoWorkbookImporter $importer,
    ): RedirectResponse {
        $data = $request->validate([
            'source' => ['required', 'file', 'mimes:xlsx', 'max:20480'],
        ]);

        try {
            $result = $importer->import(
                $data['source']->getRealPath(),
                (int) company_id(),
                user_id(),
            );
        } catch (Throwable $exception) {
            report($exception);

            return $this->backToPage('导入失败，请确认工作簿表头、文件格式和内容后重试。', 'error');
        }

        return $this->backToPage(sprintf(
            '导入完成：%s，新增 %d 条，跳过已存在 %d 条。',
            $result['sheet'],
            $result['created'],
            $result['skipped'],
        ));
    }

    private function filters(): array
    {
        $status = (string) request('status', '');

        return [
            'status' => $status === self::OVERDUE_FILTER
                || in_array($status, SystemizationTodo::STATUSES, true)
                ? $status
                : '',
            'category' => trim((string) request('category', '')),
            'owners' => $this->peopleFilter('owner'),
            'assignees' => $this->peopleFilter('assignee'),
            'start_date' => $this->normalizeDateFilter(request('start_date')),
            'due_date' => $this->normalizeDateFilter(request('due_date')),
            'keyword' => trim((string) request('keyword', '')),
        ];
    }

    private function peopleFilter(string $key): array
    {
        return collect((array) request($key, []))
            ->filter(static fn (mixed $value): bool => is_string($value))
            ->map(static fn (string $value): string => trim($value))
            ->filter()
            ->unique()
            ->take(50)
            ->values()
            ->all();
    }

    private function peopleOptions(string $column): Collection
    {
        return SystemizationTodo::query()
            ->whereNotNull($column)
            ->where($column, '<>', '')
            ->pluck($column)
            ->flatMap(static fn (string $value): array => array_map('trim', preg_split('/[、,，]/u', $value) ?: []))
            ->filter()
            ->unique()
            ->sort()
            ->values();
    }

    private function normalizeDateFilter(mixed $value): string
    {
        $value = trim((string) $value);
        if ($value === '') {
            return '';
        }

        $date = \DateTimeImmutable::createFromFormat('!Y-m-d', $value);

        return $date instanceof \DateTimeImmutable && $date->format('Y-m-d') === $value
            ? $value
            : '';
    }

    private function validated(Request $request): array
    {
        return $request->validate([
            'category' => ['nullable', 'string', 'max:100'],
            'section' => ['nullable', 'string', 'max:255'],
            'title' => ['required', 'string', 'max:5000'],
            'owner' => ['nullable', 'string', 'max:255'],
            'assignee' => ['nullable', 'string', 'max:255'],
            'start_date' => ['nullable', 'date_format:Y-m-d'],
            'due_date' => ['nullable', 'date_format:Y-m-d', 'after_or_equal:start_date'],
            'status' => ['required', Rule::in(SystemizationTodo::STATUSES)],
            'completed_at' => ['nullable', 'date_format:Y-m-d'],
            'progress' => ['nullable', 'string', 'max:10000'],
            'notes' => ['nullable', 'string', 'max:10000'],
            'screenshots' => ['nullable', 'array', 'max:12'],
            'screenshots.*' => ['file', 'mimes:jpg,jpeg,png,webp', 'max:10240'],
            'remove_attachments' => ['nullable', 'array'],
            'remove_attachments.*' => ['integer'],
        ]);
    }

    private function normalizeCompletionDates(array &$data): void
    {
        $completed = ($data['status'] ?? '') === SystemizationTodo::STATUS_COMPLETED;
        $data['completed_at'] = $completed
            ? (($data['completed_at'] ?? null) ?: ($data['due_date'] ?? null) ?: now()->toDateString())
            : null;
    }

    private function storeAttachments(Request $request, SystemizationTodo $todo): void
    {
        foreach ($request->file('screenshots', []) as $file) {
            $extension = strtolower($file->getClientOriginalExtension());
            $fileName = (string) Str::uuid() . ($extension !== '' ? '.' . $extension : '');
            $path = Storage::disk('uploads')->putFileAs(
                'systemization-todos/' . (int) company_id() . '/' . $todo->id,
                $file,
                $fileName,
            );
            if ($path === false) {
                throw new \RuntimeException('完成截图保存失败。');
            }

            SystemizationTodoAttachment::query()->create([
                'company_id' => (int) company_id(),
                'systemization_todo_id' => $todo->id,
                'path' => $path,
                'original_name' => mb_substr(basename($file->getClientOriginalName()), 0, 240),
                'mime_type' => $file->getMimeType() ?: 'application/octet-stream',
                'size' => $file->getSize() ?: 0,
                'uploaded_by' => user_id(),
            ]);
        }
    }

    private function backToPage(string $message, string $type = 'success'): RedirectResponse
    {
        return redirect()
            ->route('business.pages.show', [
                'section' => 'other',
                'page' => 'systemization-todos',
            ])
            ->with($type === 'success' ? 'success' : 'error', $message);
    }
}