<?php

namespace App\Http\Controllers;

use App\Models\Attachment;
use App\Models\AttachmentGroup;
use Illuminate\Http\JsonResponse;
use Illuminate\Http\Request;

class AttachmentGroupController extends Controller
{
    private function ensureAdmin(Request $request): ?JsonResponse
    {
        $user = $request->user();
        if (!$user || !$user->roles()->where('name', 'ROLE_ADMIN')->exists()) {
            return response()->json(['message' => 'Forbidden'], 403);
        }

        return null;
    }

    public function index(Request $request): JsonResponse
    {
        if ($error = $this->ensureAdmin($request)) {
            return $error;
        }

        $groups = AttachmentGroup::query()
            ->withCount('extensions')
            ->orderBy('parent_id')
            ->orderBy('position')
            ->orderBy('name')
            ->get()
            ->map(fn (AttachmentGroup $group) => $this->serializeGroup($group));

        return response()->json($groups);
    }

    public function store(Request $request): JsonResponse
    {
        if ($error = $this->ensureAdmin($request)) {
            return $error;
        }

        $data = $this->validatePayload($request);
        $name = trim($data['name']);
        $parentId = $this->normalizeParentId($data['parent_id'] ?? null);

        if (AttachmentGroup::query()->whereRaw('LOWER(name) = ?', [strtolower($name)])->exists()) {
            return response()->json(['message' => 'Attachment group already exists.'], 422);
        }

        $position = (AttachmentGroup::query()
            ->where('parent_id', $parentId)
            ->max('position') ?? 0) + 1;

        $group = AttachmentGroup::create([
            'name' => $name,
            'parent_id' => $parentId,
            'position' => $position,
            'max_size_kb' => $data['max_size_kb'],
            'is_active' => $data['is_active'],
        ]);

        $group->loadCount('extensions');

        return response()->json($this->serializeGroup($group), 201);
    }

    public function update(Request $request, AttachmentGroup $attachmentGroup): JsonResponse
    {
        if ($error = $this->ensureAdmin($request)) {
            return $error;
        }

        $data = $this->validatePayload($request);
        $name = trim($data['name']);
        $parentId = $this->normalizeParentId($data['parent_id'] ?? null);
        $position = $attachmentGroup->position ?? 1;

        if (AttachmentGroup::query()
            ->where('id', '!=', $attachmentGroup->id)
            ->whereRaw('LOWER(name) = ?', [strtolower($name)])
            ->exists()
        ) {
            return response()->json(['message' => 'Attachment group already exists.'], 422);
        }

        if ($attachmentGroup->parent_id !== $parentId) {
            $position = (AttachmentGroup::query()
                ->where('parent_id', $parentId)
                ->max('position') ?? 0) + 1;
        }

        $attachmentGroup->update([
            'name' => $name,
            'parent_id' => $parentId,
            'position' => $position,
            'max_size_kb' => $data['max_size_kb'],
            'is_active' => $data['is_active'],
        ]);

        $attachmentGroup->loadCount('extensions');

        return response()->json($this->serializeGroup($attachmentGroup));
    }

    public function destroy(Request $request, AttachmentGroup $attachmentGroup): JsonResponse
    {
        if ($error = $this->ensureAdmin($request)) {
            return $error;
        }

        if ($attachmentGroup->extensions()->exists()) {
            return response()->json(['message' => 'Attachment group has extensions.'], 422);
        }

        if (Attachment::query()->where('attachment_group_id', $attachmentGroup->id)->exists()) {
            return response()->json(['message' => 'Attachment group is in use.'], 422);
        }

        $attachmentGroup->delete();

        return response()->json(null, 204);
    }

    public function reorder(Request $request): JsonResponse
    {
        if ($error = $this->ensureAdmin($request)) {
            return $error;
        }

        $data = $request->validate([
            'parentId' => ['nullable'],
            'orderedIds' => ['required', 'array'],
            'orderedIds.*' => ['integer'],
        ]);

        $parentId = $data['parentId'] ?? null;
        if ($parentId === '' || $parentId === 'null') {
            $parentId = null;
        } elseif ($parentId !== null) {
            $parentId = (int) $parentId;
        }

        foreach ($data['orderedIds'] as $index => $groupId) {
            AttachmentGroup::where('id', $groupId)
                ->where('parent_id', $parentId)
                ->update(['position' => $index + 1]);
        }

        return response()->json(['status' => 'ok']);
    }

    private function validatePayload(Request $request): array
    {
        return $request->validate([
            'name' => ['required', 'string', 'max:150'],
            'parent_id' => ['nullable', 'integer', 'exists:attachment_groups,id'],
            'max_size_kb' => ['required', 'integer', 'min:1', 'max:512000'],
            'is_active' => ['required', 'boolean'],
        ]);
    }

    private function serializeGroup(AttachmentGroup $group): array
    {
        return [
            'id' => $group->id,
            'name' => $group->name,
            'parent_id' => $group->parent_id,
            'position' => $group->position,
            'max_size_kb' => $group->max_size_kb,
            'is_active' => $group->is_active,
            'extensions_count' => $group->extensions_count ?? null,
        ];
    }

    private function normalizeParentId($value): ?int
    {
        if ($value === '' || $value === 'null') {
            return null;
        }

        if ($value === null) {
            return null;
        }

        return (int) $value;
    }
}