<?php

namespace App\Http\Controllers;

use App\Exceptions\OptimisticLockConflictException;
use App\Models\Project;
use App\Models\ProjectEvent;
use App\Models\ProjectRevision;
use Illuminate\Http\RedirectResponse;
use Illuminate\Http\Request;
use Illuminate\Support\Facades\DB;
use Illuminate\Validation\ValidationException;

/**
 * The project's "confirmed current revision" is a separate pointer from the
 * per-listing liveRelease pointers on project_listing_links: it marks which
 * revision is the project's current source of truth independent of what is
 * released to any particular Etsy listing. Uploading a new revision never
 * moves this pointer; only an explicit confirm or clear does, under an
 * optimistic concurrency check on the project's own lock_version. Nothing
 * here ever mutates a revision row — it is purely a pointer update, so an
 * older revision can always be re-confirmed ("rollback") without overwriting
 * any immutable history.
 */
class ProjectCurrentRevisionController extends Controller
{
    public function update(Request $request, Project $project, ProjectRevision $revision): RedirectResponse
    {
        abort_unless($revision->project_id === $project->id, 404);
        abort_unless($request->user()->can('confirmCurrentRevision', $project), 403);

        $data = $request->validate([
            'lock_version' => ['required', 'integer', 'min:0'],
        ]);

        try {
            DB::transaction(function () use ($request, $project, $revision, $data): void {
                $locked = Project::query()->whereKey($project->id)->lockForUpdate()->firstOrFail();
                if ((int) $locked->lock_version !== (int) $data['lock_version']) {
                    throw new OptimisticLockConflictException('The project changed since you loaded it.');
                }

                $lockedRevision = ProjectRevision::query()->whereKey($revision->id)->firstOrFail();
                if ($lockedRevision->project_id !== $locked->id) {
                    abort(404);
                }
                if (! $lockedRevision->isApproved()) {
                    throw ValidationException::withMessages(['revision_id' => 'Only an approved revision can be confirmed as current.']);
                }
                if ($lockedRevision->files()->count() === 0) {
                    throw ValidationException::withMessages(['revision_id' => 'An approved revision must have at least one file before it can be confirmed as current.']);
                }

                $previousId = $locked->current_revision_id;
                $locked->update([
                    'current_revision_id' => $lockedRevision->id,
                    'lock_version' => $locked->lock_version + 1,
                ]);

                ProjectEvent::record($locked->id, 'current_revision_confirmed', $request->user()->id, ProjectRevision::class, $lockedRevision->id, [
                    'previous_current_revision_id' => $previousId,
                    'new_current_revision_id' => $lockedRevision->id,
                ]);
            });
        } catch (OptimisticLockConflictException $exception) {
            return back()->withErrors(['lock_version' => $exception->getMessage()])->setStatusCode(409);
        }

        return redirect()->route('projects.show', $project)->with('status', 'Current revision confirmed.');
    }

    public function destroy(Request $request, Project $project): RedirectResponse
    {
        abort_unless($request->user()->can('confirmCurrentRevision', $project), 403);

        $data = $request->validate([
            'lock_version' => ['required', 'integer', 'min:0'],
        ]);

        try {
            DB::transaction(function () use ($request, $project, $data): void {
                $locked = Project::query()->whereKey($project->id)->lockForUpdate()->firstOrFail();
                if ((int) $locked->lock_version !== (int) $data['lock_version']) {
                    throw new OptimisticLockConflictException('The project changed since you loaded it.');
                }

                $previousId = $locked->current_revision_id;
                $locked->update(['current_revision_id' => null, 'lock_version' => $locked->lock_version + 1]);

                ProjectEvent::record($locked->id, 'current_revision_cleared', $request->user()->id, metadata: [
                    'previous_current_revision_id' => $previousId,
                    'new_current_revision_id' => null,
                ]);
            });
        } catch (OptimisticLockConflictException $exception) {
            return back()->withErrors(['lock_version' => $exception->getMessage()])->setStatusCode(409);
        }

        return redirect()->route('projects.show', $project)->with('status', 'Current revision cleared.');
    }
}