<?php
namespace Aws\Api\Serializer;

use Aws\Api\Service;
use Aws\Api\Shape;
use Aws\Api\TimestampShape;
use Aws\Exception\InvalidJsonException;

/**
 * Formats the JSON body of a JSON-REST or JSON-RPC operation.
 * @internal
 */
class JsonBody
{
    private $api;

    public function __construct(Service $api)
    {
        $this->api = $api;
    }

    /**
     * Gets the JSON Content-Type header for a service API
     *
     * @param Service $service
     *
     * @return string
     */
    public static function getContentType(Service $service)
    {
        if ($service->getMetadata('protocol') === 'rest-json') {
            return 'application/json';
        }

        $jsonVersion = $service->getMetadata('jsonVersion');
        if (empty($jsonVersion)) {
            throw new \InvalidArgumentException('invalid json');
        } else {
            return 'application/x-amz-json-'
                . @number_format($service->getMetadata('jsonVersion'), 1);
        }
    }

    /**
     * Builds the JSON body based on an array of arguments.
     *
     * @param Shape $shape Operation being constructed
     * @param array|string $args  Associative array of arguments, or a string.
     *
     * @return string
     */
    public function build(Shape $shape, array|string $args)
    {
        try {
            $result = json_encode($this->format($shape, $args), JSON_THROW_ON_ERROR);
        } catch (\JsonException $e) {
            throw new InvalidJsonException(
                'Unable to encode JSON document ' . $shape->getName() . ': ' .
                $e->getMessage() . PHP_EOL
            );
        }

        return $result === '[]' ? '{}' : $result;
    }

    private function format(Shape $shape, $value)
    {
        switch ($shape['type']) {
            case 'structure':
                $data = [];
                if ($shape['document'] ?? false) {
                    return $value;
                }
                foreach ($value as $k => $v) {
                    if ($v !== null && $shape->hasMember($k)) {
                        $valueShape = $shape->getMember($k);
                        $data[$valueShape['locationName'] ?: $k]
                            = $this->format($valueShape, $v);
                    }
                }
                if (empty($data)) {
                    return new \stdClass;
                }
                return $data;

            case 'list':
                $items = $shape->getMember();
                foreach ($value as $k => $v) {
                    $value[$k] = $this->format($items, $v);
                }
                return $value;

            case 'map':
                if (empty($value)) {
                    return new \stdClass;
                }
                $values = $shape->getValue();
                foreach ($value as $k => $v) {
                    $value[$k] = $this->format($values, $v);
                }
                return $value;

            case 'blob':
                return base64_encode($value);

            case 'timestamp':
                $timestampFormat = !empty($shape['timestampFormat'])
                    ? $shape['timestampFormat']
                    : 'unixTimestamp';
                return TimestampShape::format($value, $timestampFormat);

            default:
                return $value;
        }
    }
}
