<?php

namespace App\Http\Controllers;

use App\Models\Project;
use App\Models\ProjectEvent;
use App\Models\ProjectFile;
use App\Models\ProjectRevision;
use App\Services\ManufacturingFileValidator;
use Illuminate\Http\RedirectResponse;
use Illuminate\Http\Request;
use Illuminate\Support\Facades\DB;
use Illuminate\Support\Facades\Storage;
use Illuminate\Validation\ValidationException;
use RuntimeException;
use Throwable;

class ProjectRevisionController extends Controller
{
    public function store(Request $request, Project $project): RedirectResponse
    {
        abort_unless($request->user()->can('manageFiles', $project), 403);
        $data = $request->validate([
            'change_notes' => ['nullable', 'string', 'max:2000'],
            'revision_id' => ['nullable', 'integer'],
            'files' => ['required', 'array', 'min:1', 'max:10'],
            'files.*' => ['file', 'max:'.(ManufacturingFileValidator::MAX_FILE_SIZE / 1024)],
            'roles' => ['sometimes', 'array'],
            'roles.*' => ['nullable', 'string', 'max:64'],
            'fusion_project_id' => ['nullable', 'string', 'max:255'],
            'fusion_document_id' => ['nullable', 'string', 'max:255'],
            'fusion_version' => ['nullable', 'string', 'max:255'],
        ]);

        $totalBytes = array_sum(array_map(fn ($file) => (int) $file->getSize(), $data['files']));
        if ($totalBytes > ManufacturingFileValidator::MAX_TOTAL_BATCH_SIZE) {
            throw ValidationException::withMessages(['files' => 'The combined size of all files in this upload is too large.']);
        }

        $validator = new ManufacturingFileValidator;
        $disk = Storage::disk('project_files');
        $storedKeys = [];

        try {
            $revision = DB::transaction(function () use ($request, $project, $data, $validator, $disk, &$storedKeys): ProjectRevision {
                Project::query()->whereKey($project->id)->lockForUpdate()->firstOrFail();
                $revision = $this->resolveWritableRevision($project, $request->user()->id, $data);

                foreach ($data['files'] as $index => $uploadedFile) {
                    try {
                        $validated = $validator->validate($uploadedFile);
                    } catch (RuntimeException $exception) {
                        throw ValidationException::withMessages(["files.{$index}" => $exception->getMessage()]);
                    }

                    $key = bin2hex(random_bytes(20)).'.'.$validated['extension'];
                    $stream = fopen($uploadedFile->getRealPath(), 'rb');
                    if ($stream === false || $disk->put($key, $stream) === false) {
                        if (is_resource($stream)) {
                            fclose($stream);
                        }

                        throw new RuntimeException("Unable to store uploaded file: {$uploadedFile->getClientOriginalName()}.");
                    }
                    if (is_resource($stream)) {
                        fclose($stream);
                    }
                    $storedKeys[] = $key;

                    ProjectFile::create([
                        'revision_id' => $revision->id,
                        'role' => $data['roles'][$index] ?? 'component',
                        'original_filename' => $uploadedFile->getClientOriginalName(),
                        'storage_key' => $key,
                        'extension' => $validated['extension'],
                        'media_type' => $validated['media_type'],
                        'byte_size' => $uploadedFile->getSize(),
                        'sha256' => hash_file('sha256', $uploadedFile->getRealPath()),
                        'uploaded_by' => $request->user()->id,
                    ]);
                }

                ProjectEvent::record($project->id, 'revision_uploaded', $request->user()->id, ProjectRevision::class, $revision->id, [
                    'revision_number' => $revision->revision_number,
                    'file_count' => count($data['files']),
                ]);

                return $revision;
            });
        } catch (Throwable $exception) {
            foreach ($storedKeys as $key) {
                $disk->delete($key);
            }

            throw $exception;
        }

        return redirect()->route('projects.show', $project)->with('status', 'Revision uploaded.');
    }

    public function approve(Request $request, Project $project, ProjectRevision $revision): RedirectResponse
    {
        abort_unless($revision->project_id === $project->id, 404);
        abort_unless($request->user()->can('manageFiles', $project), 403);

        DB::transaction(function () use ($request, $project, $revision): void {
            Project::query()->whereKey($project->id)->lockForUpdate()->firstOrFail();
            $locked = ProjectRevision::query()->whereKey($revision->id)->lockForUpdate()->firstOrFail();

            abort_if($locked->isApproved(), 422, 'This revision is already approved.');
            abort_if($locked->files()->count() === 0, 422, 'A revision needs at least one file before it can be approved.');

            $locked->update([
                'status' => ProjectRevision::STATUS_APPROVED,
                'approved_by' => $request->user()->id,
                'approved_at' => now(),
            ]);
            ProjectEvent::record($project->id, 'revision_approved', $request->user()->id, ProjectRevision::class, $locked->id, [
                'revision_number' => $locked->revision_number,
            ]);
        });

        return redirect()->route('projects.show', $project)->with('status', 'Revision approved.');
    }

    /**
     * @param  array<string, mixed>  $data
     */
    private function resolveWritableRevision(Project $project, int $userId, array $data): ProjectRevision
    {
        if (! empty($data['revision_id'])) {
            $candidate = $project->revisions()->find($data['revision_id']);
            if ($candidate && ! $candidate->isApproved()) {
                return $candidate;
            }
        }

        $nextNumber = (int) $project->revisions()->max('revision_number') + 1;

        return $project->revisions()->create([
            'revision_number' => $nextNumber,
            'change_notes' => $data['change_notes'] ?? null,
            'fusion_project_id' => $data['fusion_project_id'] ?? null,
            'fusion_document_id' => $data['fusion_document_id'] ?? null,
            'fusion_version' => $data['fusion_version'] ?? null,
            'status' => ProjectRevision::STATUS_DRAFT,
            'created_by' => $userId,
        ]);
    }
}