<?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('*'))
            ->orderBy('sort_order')
            ->orderBy('id')
            ->get();
        $sequenceMap = $this->hierarchySequenceMap();
        $items->each(function (SystemizationTodo $todo) use ($sequenceMap): void {
            $sequence = $sequenceMap[$todo->id] ?? [
                'type_sequence' => 0,
                'content_sequence' => 0,
                'item_sequence' => 0,
                'order' => PHP_INT_MAX,
                'category_display' => '',
                'section_display' => '',
            ];
            $todo->setAttribute('type_sequence', $sequence['type_sequence']);
            $todo->setAttribute('content_sequence', $sequence['content_sequence']);
            $todo->setAttribute('item_sequence', $sequence['item_sequence']);
            $todo->setAttribute('hierarchy_order', $sequence['order']);
            $todo->setAttribute('category_display', $sequence['category_display']);
            $todo->setAttribute('section_display', $sequence['section_display']);
        });
        $items = $items->sortBy('hierarchy_order')->values();
        if ($filters['type_sequence'] > 0) {
            $items = $items
                ->filter(static fn (SystemizationTodo $todo): bool =>
                    (int) $todo->type_sequence === $filters['type_sequence']
                )
                ->values();
        }
        if ($filters['content_sequence'] > 0) {
            $items = $items
                ->filter(static fn (SystemizationTodo $todo): bool =>
                    (int) $todo->content_sequence === $filters['content_sequence']
                )
                ->values();
        }
        if ($filters['item_sequence'] > 0) {
            $items = $items
                ->filter(static fn (SystemizationTodo $todo): bool =>
                    (int) $todo->item_sequence === $filters['item_sequence']
                )
                ->values();
        }

        $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'),
            ],
        ];
    }

    private function hierarchySequenceMap(): array
    {
        $todos = SystemizationTodo::query()
            ->orderBy('sort_order')
            ->orderBy('id')
            ->get(['id', 'category', 'section', 'sort_order']);
        $rows = $todos->map(function (SystemizationTodo $todo): array {
            $category = $this->hierarchyLabel($todo->category);
            $section = $this->hierarchyLabel($todo->section);

            return [
                'category_key' => $category === '' ? "\0" : $category,
                'category_label' => $category,
                'section_key' => $section === '' ? "\0" : $section,
                'section_label' => $section,
                'sort_order' => (int) $todo->sort_order,
                'id' => (int) $todo->id,
            ];
        })->all();

        $categoryOrder = [];
        $categoryLabels = [];
        $sectionOrder = [];
        $sectionLabels = [];
        $groupedRows = [];
        foreach ($rows as $row) {
            $categoryKey = $row['category_key'];
            $sectionKey = $row['section_key'];
            $categoryOrder[$categoryKey] = min(
                $categoryOrder[$categoryKey] ?? PHP_INT_MAX,
                $row['sort_order'],
            );
            $categoryLabels[$categoryKey] = $row['category_label'];
            $sectionOrder[$categoryKey][$sectionKey] = min(
                $sectionOrder[$categoryKey][$sectionKey] ?? PHP_INT_MAX,
                $row['sort_order'],
            );
            $sectionLabels[$categoryKey][$sectionKey] = $row['section_label'];
            $groupedRows[$categoryKey][$sectionKey][] = $row;
        }

        $categoryKeys = array_keys($categoryOrder);
        usort($categoryKeys, function (string $left, string $right) use (
            $categoryOrder,
            $categoryLabels,
        ): int {
            return $this->compareHierarchyGroups(
                $left,
                $right,
                $categoryOrder,
                $categoryLabels,
            );
        });

        $sequenceMap = [];
        $hierarchyOrder = 0;
        foreach ($categoryKeys as $categoryIndex => $categoryKey) {
            $contentKeys = array_keys($sectionOrder[$categoryKey]);
            usort($contentKeys, function (string $left, string $right) use (
                $categoryKey,
                $sectionOrder,
                $sectionLabels,
            ): int {
                return $this->compareHierarchyGroups(
                    $left,
                    $right,
                    $sectionOrder[$categoryKey],
                    $sectionLabels[$categoryKey],
                );
            });

            foreach ($contentKeys as $contentIndex => $contentKey) {
                $contentRows = $groupedRows[$categoryKey][$contentKey];
                usort($contentRows, static fn (array $left, array $right): int =>
                    [$left['sort_order'], $left['id']] <=> [$right['sort_order'], $right['id']]
                );

                foreach ($contentRows as $itemIndex => $row) {
                    $sequenceMap[$row['id']] = [
                        'type_sequence' => $categoryIndex + 1,
                        'content_sequence' => $contentIndex + 1,
                        'item_sequence' => $itemIndex + 1,
                        'order' => $hierarchyOrder++,
                        'category_display' => $row['category_label'],
                        'section_display' => $row['section_label'],
                    ];
                }
            }
        }

        return $sequenceMap;
    }

    private function compareHierarchyGroups(
        string $left,
        string $right,
        array $sortOrders,
        array $labels,
    ): int {
        $comparison = ($sortOrders[$left] ?? PHP_INT_MAX) <=> ($sortOrders[$right] ?? PHP_INT_MAX);

        return $comparison !== 0
            ? $comparison
            : strnatcasecmp($labels[$left] ?? '', $labels[$right] ?? '');
    }

    private function hierarchyLabel(?string $value): string
    {
        return trim((string) preg_replace(
            '/^\s*(?:\d+|[一二三四五六七八九十百]+)\s*[、.．:：)]\s*/u',
            '',
            (string) $value,
        ));
    }

    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('待办事项已新增并定位。', 'success', $todo);
    }

    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('待办事项已更新并定位。', 'success', $todo);
    }

    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->sync(
                $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(
            '同步完成：%s，新增 %d 条，更新 %d 条，保留工作簿外事项 %d 条。',
            $result['sheet'],
            $result['created'],
            $result['updated'],
            $result['retained'],
        ));
    }

    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')),
            'type_sequence' => max(0, (int) request('type_sequence', 0)),
            'content_sequence' => max(0, (int) request('content_sequence', 0)),
            'item_sequence' => max(0, (int) request('item_sequence', 0)),
            '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',
        ?SystemizationTodo $focus = null,
    ): RedirectResponse
    {
        $parameters = [
            'section' => 'other',
            'page' => 'systemization-todos',
        ];
        if ($focus) {
            $parameters['highlight'] = $focus->id;
        }

        return redirect()
            ->route('business.pages.show', $parameters)
            ->with($type === 'success' ? 'success' : 'error', $message);
    }
}