<?php
class TSGen
{

    public static function fromJSON(string $json, string $interfaceName): string
    {
        try {
            return self::generateInterface(json_decode($json, true, 512, JSON_THROW_ON_ERROR), $interfaceName);
        } catch (JsonException $e) {
            throw new InvalidArgumentException("Error parsing JSON: " . $e->getMessage());
        }
    }
    public static function fromArray(array $data, string $interfaceName): string
    {
        return self::generateInterface($data, $interfaceName);
    }
    //note that this only works for public properties
    public static function fromObject(object $object, string $interfaceName = "", bool $useNamespacedClassName = false, $glue = "_"): string
    {
        if ($interfaceName !== "")
            return self::generateInterface(get_object_vars($object), $interfaceName);
        if ((new ReflectionClass($object))->isAnonymous()) {
            throw new InvalidArgumentException("Anonymous classes must have an interface name");
        }
        if (!$useNamespacedClassName) {
            $name = self::toCamelCase(strrchr(get_class($object), "\\"));
        } else {
            $name = self::toCamelCase(str_replace("\\", $glue, get_class($object)));
        }
        return self::generateInterface(get_object_vars($object), $name);
    }
    // Implementation details
    private static function toCamelCase(string $string): string
    {
        return lcfirst(str_replace(' ', '', ucwords(str_replace(['-', '_'], ' ', $string))));
    }
    // Generate TypeScript interface definitions from JSON data
    private static function generateInterface(array $data, string $interfaceName): string
    {
        return "interface $interfaceName " . self::generateInterfaceImpl($data) . ";\n";
    }

    private static function indent(string $code, int $level = 1): string
    {
        return implode("\n", array_map(fn($line) => str_repeat("    ", $level) . $line, explode("\n", $code)));
    }
    private static function generateInterfaceImpl(array $data, int $indent = 0): string
    {
        $definitions = ["{"];
        $indent++;

        foreach ($data as $key => $value) {
            array_push($definitions, self::indent("$key: " .
                match (gettype($value)) {
                    'array' => array_is_list($value) ? self::guessArrayElementType($value) : self::generateInterfaceImpl($value),
                    'object' => self::generateInterfaceImpl(get_object_vars($value)),
                    default => self::getTSType($value)
                } . ";", $indent));
        }

        $definitions[] = "}";
        return implode("\n", $definitions);
    }
    private static function getTSType($value): string
    {
        return match (gettype($value)) {
            'integer', 'double' => 'number',
            'boolean' => 'boolean',
            'string' => 'string',
            'array' => self::guessArrayElementType($value),
            'NULL' => 'null',
            default => 'any'
        };
    }

    private static function guessArrayElementType(array $data): string
    {
        $types = [];
        foreach ($data as $value) {
            $types[] = self::getTSType($value);
        }
        return "Array<" . implode(' | ', array_unique($types)) . ">";
    }
}