muninn/app/Support/VideoWorkflow/StepHandlers/StoryboardHandler.php

<?php

namespace App\Support\VideoWorkflow\StepHandlers;

use App\Models\AiProvider;
use App\Models\WorkflowStep;
use App\Support\AiProviders\AiGenerationException;
use App\Support\AiProviders\AiProviderManager;
use App\Support\AssetStorage\AssetStorage;
use App\Support\VideoWorkflow\WorkflowEngine;

/**
 * Breaks the project's script into a numbered scene-by-scene storyboard —
 * each scene gets a description and an image-generation prompt — via an
 * OpenAI-backed AiProvider in JSON mode. Produces the text/description
 * layer only; VideoGenerationHandler turns each scene's visual_prompt into
 * an actual image.
 */
class StoryboardHandler implements StepHandler
{
    public function __construct(
        private readonly AiProviderManager $aiProviders,
        private readonly AssetStorage $assets,
    ) {}

    public function type(): string
    {
        return 'storyboard';
    }

    public function handle(WorkflowStep $step, WorkflowEngine $engine): void
    {
        $provider = AiProvider::query()->where('provider', 'openai')->where('is_active', true)->first();

        if (! $provider) {
            $engine->failStep($step, 'No active OpenAI provider configured.');

            return;
        }

        $script = $this->resolveScript($step);

        if (! $script) {
            $engine->failStep($step, 'No script available to storyboard — complete a script_generation step first.');

            return;
        }

        try {
            $result = $this->aiProviders->generate($provider, $this->buildPrompt($step, $script), ['json_mode' => true]);
        } catch (AiGenerationException $e) {
            $engine->failStep($step, $e->getMessage());

            return;
        }

        $decoded = json_decode($result->content, true);
        $scenes = $decoded['scenes'] ?? null;

        if (! is_array($scenes) || empty($scenes)) {
            $engine->failStep($step, 'AI provider returned an unusable storyboard: no scenes found.');

            return;
        }

        $asset = $this->assets->store(
            $step->videoProject,
            'other',
            json_encode(['scenes' => $scenes], JSON_PRETTY_PRINT),
            'json',
            step: $step,
            mimeType: 'application/json',
            metadata: ['kind' => 'storyboard', 'scene_count' => count($scenes)],
        );

        $engine->completeStep($step, [
            'asset_id' => $asset->id,
            'scene_count' => count($scenes),
        ]);
    }

    private function resolveScript(WorkflowStep $step): ?string
    {
        $input = $step->input ?? [];

        if (! empty($input['script'])) {
            return $input['script'];
        }

        $scriptAsset = $step->videoProject->assets()
            ->where('type', 'script')
            ->orderByDesc('version')
            ->first();

        return $scriptAsset ? $this->assets->contents($scriptAsset) : null;
    }

    private function buildPrompt(WorkflowStep $step, string $script): string
    {
        $input = $step->input ?? [];

        $prompt = "Break the following video script into a numbered scene-by-scene storyboard.\n\n"
            ."Script:\n{$script}\n\n"
            .'For each scene provide: scene_number (integer), description (what happens on screen), '
            ."and visual_prompt (a concise, self-contained image-generation prompt describing this scene's visual).";

        if (! empty($input['style'])) {
            $prompt .= " Every visual_prompt must consistently reflect this visual style: {$input['style']}.";
        }

        $prompt .= "\n\nRespond with JSON only, in exactly this shape: "
            .'{"scenes": [{"scene_number": 1, "description": "...", "visual_prompt": "..."}]}';

        return $prompt;
    }
}