<?php

namespace App\Domains\Tenant\Services;

use App\Domains\Attachable\Enums\AttachmentType;
use App\Domains\Attachable\Models\Attachment;
use App\Domains\Attachable\Services\AttachmentService;
use App\Domains\Shared\Rules\ImageOrBase64Rule;
use App\Domains\Tenant\Models\Tenant;
use App\Domains\Tenant\Models\WebsiteType;
use App\Domains\Tenant\Models\WebsiteTypeExtra;
use Illuminate\Support\Collection;
use Illuminate\Support\Facades\Validator;
use Illuminate\Support\Str;
use Illuminate\Validation\ValidationException;
use InvalidArgumentException;

class WebsiteExtraService
{
    public function __construct(protected AttachmentService $attachmentService) {}

    /**
     * Build the request rules declared by the selected website type.
     *
     * @return array<string, mixed>
     */
    public function requestRules(?string $websiteTypeCode): array
    {
        if (! is_string($websiteTypeCode) || $websiteTypeCode === '') {
            return [
                'extras' => ['prohibited'],
            ];
        }

        $definitions = $this->definitionsFor($websiteTypeCode);
        $allowedNames = $definitions->pluck('nombre')->all();
        $hasRequiredExtras = $definitions->contains(
            fn (WebsiteTypeExtra $definition): bool => $definition->is_required
        );

        $rules = [
            'extras' => [
                $hasRequiredExtras ? 'required' : 'sometimes',
                'array',
                function (string $attribute, mixed $value, \Closure $fail) use ($allowedNames): void {
                    if (! is_array($value)) {
                        return;
                    }

                    $unknownNames = array_diff(array_keys($value), $allowedNames);

                    if ($unknownNames !== []) {
                        $fail(
                            'The '.$attribute.' field contains extras not supported by the website type: '
                            .implode(', ', $unknownNames).'.'
                        );
                    }
                },
            ],
        ];

        foreach ($definitions as $definition) {
            $schemaRules = $definition->config_schema['request_rules'] ?? [];
            $rootRules = $this->compileRules($schemaRules['$'] ?? []);
            $rootRules = array_values(array_filter(
                $rootRules,
                fn (mixed $rule): bool => ! in_array($rule, ['required', 'sometimes'], true)
            ));
            array_unshift($rootRules, $definition->is_required ? 'required' : 'sometimes');

            $rules["extras.{$definition->nombre}"] = $rootRules;

            foreach ($schemaRules as $path => $pathRules) {
                if ($path === '$') {
                    continue;
                }

                $rules[$this->requestAttribute($definition->nombre, $path)] = $this->compileRules($pathRules);
            }
        }

        return $rules;
    }

    /**
     * Transform and persist each extra selected for a tenant.
     *
     * @param  array<string, mixed>  $extras
     */
    public function createForTenant(Tenant $tenant, array $extras): void
    {
        if ($extras === []) {
            return;
        }

        $definitions = $this->definitionsFor((string) $tenant->website_type_code)
            ->keyBy('nombre');

        foreach ($extras as $name => $config) {
            /** @var WebsiteTypeExtra|null $definition */
            $definition = $definitions->get($name);

            if (! $definition) {
                throw ValidationException::withMessages([
                    'extras' => ["The extra {$name} is not supported by the selected website type."],
                ]);
            }

            $transformedConfig = $this->applyTransforms($tenant, $definition, $config);
            $this->validateDatabaseConfig($definition, $transformedConfig);

            $tenant->websiteExtras()->create([
                'website_type_extra_id' => $definition->id,
                'config' => $transformedConfig,
            ]);
        }

        $tenant->unsetRelation('websiteExtras');
    }

    /**
     * @return Collection<int, WebsiteTypeExtra>
     */
    private function definitionsFor(string $websiteTypeCode): Collection
    {
        $websiteType = WebsiteType::query()
            ->where('codigo', $websiteTypeCode)
            ->with('extras')
            ->first();

        return $websiteType?->extras ?? collect();
    }

    /**
     * @param  string|array<int, mixed>  $rules
     * @return array<int, mixed>
     */
    private function compileRules(string|array $rules): array
    {
        $compiled = is_string($rules) ? explode('|', $rules) : $rules;

        return array_map(
            fn (mixed $rule): mixed => $rule === 'image_or_base64'
                ? new ImageOrBase64Rule
                : $rule,
            $compiled
        );
    }

    private function requestAttribute(string $extraName, string $path): string
    {
        if ($path === '$') {
            return "extras.{$extraName}";
        }

        if (str_starts_with($path, '$.')) {
            $path = substr($path, 2);
        }

        return "extras.{$extraName}.{$path}";
    }

    private function applyTransforms(
        Tenant $tenant,
        WebsiteTypeExtra $definition,
        mixed $config
    ): mixed {
        foreach ($definition->config_schema['transforms'] ?? [] as $path => $transform) {
            $segments = $this->pathSegments($path);
            $config = $this->transformAtPath(
                $config,
                $segments,
                fn (mixed $value): mixed => $this->transformValue(
                    $tenant,
                    $definition,
                    $path,
                    $value,
                    $transform
                )
            );
        }

        return $config;
    }

    /**
     * @return array<int, string>
     */
    private function pathSegments(string $path): array
    {
        $path = ltrim($path, '$');
        $path = ltrim($path, '.');

        return $path === '' ? [] : explode('.', $path);
    }

    private function transformAtPath(mixed $value, array $segments, callable $transform): mixed
    {
        if ($segments === []) {
            return $transform($value);
        }

        if (! is_array($value)) {
            return $value;
        }

        $segment = array_shift($segments);

        if ($segment === '*') {
            foreach ($value as $key => $item) {
                $value[$key] = $this->transformAtPath($item, $segments, $transform);
            }

            return $value;
        }

        if (array_key_exists($segment, $value)) {
            $value[$segment] = $this->transformAtPath($value[$segment], $segments, $transform);
        }

        return $value;
    }

    /**
     * @param  array<string, mixed>  $transform
     */
    private function transformValue(
        Tenant $tenant,
        WebsiteTypeExtra $definition,
        string $path,
        mixed $value,
        array $transform
    ): mixed {
        if ($value === null) {
            return null;
        }

        if (($transform['handler'] ?? null) !== 'attachment') {
            throw new InvalidArgumentException(
                "Unsupported transform handler for {$definition->nombre}: ".($transform['handler'] ?? 'null')
            );
        }

        if (is_string($value) && Str::isUuid($value)) {
            $attachment = Attachment::query()->where('key', $value)->first();

            if (! $attachment) {
                throw ValidationException::withMessages([
                    $this->requestAttribute($definition->nombre, $path) => [
                        'The selected attachment does not exist.',
                    ],
                ]);
            }
        } else {
            $attachment = $this->attachmentService->store(
                $value,
                "tenants/{$tenant->codigo}/extras/{$definition->nombre}"
            );
        }

        $expectedType = $transform['attachment_type'] ?? null;

        if (
            is_string($expectedType)
            && $attachment->type instanceof AttachmentType
            && $attachment->type->value !== $expectedType
        ) {
            throw ValidationException::withMessages([
                $this->requestAttribute($definition->nombre, $path) => [
                    "The attachment must be of type {$expectedType}.",
                ],
            ]);
        }

        return $attachment->id;
    }

    private function validateDatabaseConfig(
        WebsiteTypeExtra $definition,
        mixed $config
    ): void {
        $schemaRules = $definition->config_schema['database_rules'] ?? [];
        $rules = [];

        foreach ($schemaRules as $path => $pathRules) {
            $attribute = $path === '$'
                ? 'config'
                : 'config.'.ltrim(str_starts_with($path, '$.') ? substr($path, 2) : $path, '.');
            $rules[$attribute] = $this->compileRules($pathRules);
        }

        $validator = Validator::make(['config' => $config], $rules);

        if ($validator->fails()) {
            $messages = [];

            foreach ($validator->errors()->toArray() as $attribute => $errors) {
                $suffix = $attribute === 'config' ? '' : substr($attribute, strlen('config'));
                $messages["extras.{$definition->nombre}{$suffix}"] = $errors;
            }

            throw ValidationException::withMessages($messages);
        }
    }
}