<?php

namespace App\Services;

use App\Ai\Agents\MealMaker;
use App\Enums\IngredientUnit;
use App\Enums\MealPostType;
use App\Enums\MealPostVisibility;
use App\Models\MealPosts;
use App\Models\User;
use Illuminate\Contracts\Support\Arrayable;
use Illuminate\Support\Facades\DB;
use Illuminate\Support\Facades\Hash;
use Illuminate\Support\Str;
use Laravel\Ai\Image;
use RuntimeException;

class AiMealPostGenerator
{
    public function generate(): MealPosts
    {
        $draft = $this->generateMealDraft();
        $imagePath = $this->generateMealImage($draft);
        $ingredients = $draft['ingredients'];

        unset($draft['ingredients'], $draft['image_prompt']);

        return DB::transaction(function () use ($draft, $imagePath, $ingredients): MealPosts {
            $mealPost = MealPosts::create([
                ...$draft,
                'user_id' => $this->aiUser()->getKey(),
                'image_url' => $imagePath,
                'visibility' => MealPostVisibility::Public,
                'ai_generated' => true,
                'eaten_at' => now(),
            ]);

            if ($ingredients !== []) {
                $mealPost->ingredients()->createMany($ingredients);
            }

            return $mealPost->loadMissing('user:id,name,avatar_url', 'ingredients');
        });
    }

    private function generateMealDraft(): array
    {
        $response = MealMaker::make()->prompt($this->mealPrompt(), timeout: $this->textTimeout());

        return $this->normalizeDraft(
            $response instanceof Arrayable
                ? $response->toArray()
                : (json_decode($response->text ?? '', true) ?: [])
        );
    }

    private function generateMealImage(array $draft): string
    {
        $path = Image::of($this->imagePrompt($draft))
            ->landscape()
            ->quality($this->imageQuality())
            ->timeout($this->imageTimeout())
            ->generate()
            ->storePublicly($this->imageStoragePath(), 'public');

        if (! is_string($path)) {
            throw new RuntimeException("L'image du repas IA n'a pas pu etre stockee.");
        }

        return $path;
    }

    private function aiUser(): User
    {
        $email = $this->configString('user_email', 'ai@daily-meal.local');

        return User::query()->firstOrCreate(
            ['email' => $email],
            [
                'name' => $this->configString('user_name', 'Daily Meal AI'),
                'password' => Hash::make(Str::random(64)),
                'bio' => 'Compte utilise pour publier des repas generes automatiquement.',
            ],
        );
    }

    private function mealPrompt(): string
    {
        $season = now()->locale('fr')->translatedFormat('F');

        return <<<PROMPT
Genere un plat aleatoire pour le mois de {$season}.

Contraintes:
- Le plat doit etre realiste, appetissant et suffisamment different des classiques trop evidents.
- Retourne une seule portion avec calories, macros et ingredients coherents.
- Evite les aliments impossibles a representer clairement en photo.
- Auncun texte sur l'image
PROMPT;
    }

    private function imagePrompt(array $draft): string
    {
        $prompt = $this->cleanString($draft['image_prompt'] ?? '', 1500);

        if ($prompt === '') {
            $prompt = "Photorealistic food photography of {$draft['title']}, single serving, natural light, restaurant plating.";
        }

        return $prompt.' No text, no watermark, no people, no hands.';
    }

    private function normalizeDraft(array $draft): array
    {
        $type = MealPostType::tryFrom($this->cleanString($draft['type'] ?? '', 32))
            ?? MealPostType::OTHER;

        return [
            'title' => $this->cleanString($draft['title'] ?? 'Repas IA', 255) ?: 'Repas IA',
            'caption' => $this->cleanString($draft['caption'] ?? '', 1000),
            'type' => $type,
            'calories' => $this->positiveInteger($draft['calories'] ?? 0),
            'proteins' => $this->positiveNumber($draft['proteins'] ?? 0),
            'carbs' => $this->positiveNumber($draft['carbs'] ?? 0),
            'fats' => $this->positiveNumber($draft['fats'] ?? 0),
            'ingredients' => $this->normalizeIngredients($draft['ingredients'] ?? []),
            'image_prompt' => $this->cleanString($draft['image_prompt'] ?? '', 1500),
        ];
    }

    private function normalizeIngredients(mixed $ingredients): array
    {
        if (! is_array($ingredients)) {
            return [];
        }

        $normalized = [];

        foreach (array_slice($ingredients, 0, 12) as $ingredient) {
            if (! is_array($ingredient)) {
                continue;
            }

            $name = $this->cleanString($ingredient['ingredient'] ?? '', 255);

            if ($name === '') {
                continue;
            }

            $unit = IngredientUnit::tryFrom($this->cleanString($ingredient['unit'] ?? '', 16))
                ?? IngredientUnit::GRAM;

            $normalized[] = [
                'position' => count($normalized) + 1,
                'ingredient' => $name,
                'quantity' => max(1, $this->positiveInteger($ingredient['quantity'] ?? 1)),
                'unit' => $unit,
            ];
        }

        return $normalized;
    }

    private function cleanString(mixed $value, int $limit): string
    {
        if (! is_string($value) && ! is_numeric($value)) {
            return '';
        }

        $cleaned = trim((string) preg_replace('/\s+/', ' ', (string) $value));

        return Str::limit($cleaned, $limit, '');
    }

    private function positiveInteger(mixed $value): int
    {
        if (! is_numeric($value)) {
            return 0;
        }

        return max(0, (int) round((float) $value));
    }

    private function positiveNumber(mixed $value): float
    {
        if (! is_numeric($value)) {
            return 0;
        }

        return round(max(0, (float) $value), 1);
    }

    private function imageQuality(): string
    {
        $quality = $this->configString('image_quality', 'medium');

        return in_array($quality, ['low', 'medium', 'high'], true) ? $quality : 'medium';
    }

    private function imageStoragePath(): string
    {
        return $this->configString('image_path', 'meal-posts/ai-generated');
    }

    private function textTimeout(): int
    {
        return max(1, (int) config('meal_posts.ai_generation.text_timeout', 90));
    }

    private function imageTimeout(): int
    {
        return max(1, (int) config('meal_posts.ai_generation.image_timeout', 120));
    }

    private function configString(string $key, string $fallback): string
    {
        $value = trim((string) config("meal_posts.ai_generation.{$key}", $fallback));

        return $value !== '' ? $value : $fallback;
    }
}