<?php

namespace mindplay;

use Closure;
use Error;
use ErrorException;
use Exception;
use ReflectionFunction;
use Throwable;

/**
 * Pseudo-namespace for functions that generate human-readable string representations
 * of most types of PHP values.
 */
abstract class readable
{
    /**
     * @var int strings longer than this number of characters will be truncated when formatting string-values
     */
    public static $max_string_length = 120;

    /**
     * @var string[] map where PHP error severity code => constant name
     */
    public static $severity_names = [
        E_ERROR             => "E_ERROR",
        E_USER_ERROR        => "E_USER_ERROR",
        E_CORE_ERROR        => "E_CORE_ERROR",
        E_COMPILE_ERROR     => "E_COMPILE_ERROR",
        E_PARSE             => "E_PARSE",
        E_WARNING           => "E_WARNING",
        E_USER_WARNING      => "E_USER_WARNING",
        E_CORE_WARNING      => "E_CORE_WARNING",
        E_COMPILE_WARNING   => "E_COMPILE_WARNING",
        E_NOTICE            => "E_NOTICE",
        E_USER_NOTICE       => "E_USER_NOTICE",
        E_STRICT            => "E_STRICT",
        E_RECOVERABLE_ERROR => "E_RECOVERABLE_ERROR",
        E_DEPRECATED        => "E_DEPRECATED",
        E_USER_DEPRECATED   => "E_USER_DEPRECATED",
    ];

    /**
     * @param mixed $value any type of PHP value
     *
     * @return string readable representation of the given value
     */
    public static function value($value)
    {
        $type = is_array($value) && is_callable($value)
            ? "callable"
            : strtolower(gettype($value));

        switch ($type) {
            case "boolean":
                return $value ? "true" : "false";

            case "integer":
                return number_format($value, 0, "", "");

            case "double": // (for historical reasons "double" is returned in case of a float, and not simply "float")
                $formatted = sprintf("%.6g", $value);

                return $value == $formatted
                    ? "{$formatted}"
                    : "~{$formatted}";

            case "string":
                $string = strlen($value) > self::$max_string_length
                    ? substr($value, 0, self::$max_string_length) . "...[" . strlen($value) . "]"
                    : $value;

                return '"' . addslashes($string) . '"';

            case "array":
                return "[" . self::values($value) . "]";

            case "object":
                if ($value instanceof Closure) {
                    $reflection = new ReflectionFunction($value);

                    return "{Closure in " . $reflection->getFileName() . "({$reflection->getStartLine()})}";
                }

                return "{" . ($value instanceof \stdClass ? "object" : get_class($value)) . "}";

            case "resource":
                return "{" . get_resource_type($value) . "}";

            case "callable":
                return is_object($value[0])
                    ? '{' . get_class($value[0]) . "}->{$value[1]}()"
                    : "{$value[0]}::{$value[1]}()";

            case "null":
                return "null";
        }

        return "{{$type}}"; // "unknown type" and possibly unsupported (future) types
    }

    /**
     * @param array $array array containing any type of PHP values
     *
     * @return string comma-separated human-readable representation of the given values
     */
    public static function values(array $array)
    {
        $formatted = array_map(['mindplay\\readable', 'value'], $array);

        if (array_keys($array) !== range(0, count($array) - 1)) {
            foreach ($formatted as $name => $value) {
                $formatted[$name] = self::value($name) . " => {$value}";
            }
        }

        return implode(", ", $formatted);
    }

    /**
     * @param mixed $value any type of PHP value
     *
     * @return string human-readable type-name
     */
    public static function typeof($value)
    {
        $type = ! is_string($value) && ! is_object($value) && is_callable($value)
            ? "callable"
            : strtolower(gettype($value));

        switch ($type) {
            case "boolean":
                return "bool";
            case "integer":
                return "int";
            case "double":
                return "float";
            case "object":
                return $value instanceof \stdClass ? "object" : get_class($value);
            case "string":
            case "array":
            case "resource":
            case "callable":
            case "null":
                return $type;
        }

        return "unknown";
    }

    /**
     * @param mixed $callable
     *
     * @return string human-readable description of callback
     */
    public static function callback($callable)
    {
        if (is_string($callable) && is_callable($callable)) {
            return "{$callable}()";
        } elseif (is_object($callable) && method_exists($callable, "__invoke")) {
            return $callable instanceof Closure
                ? self::value($callable)
                : "{" . get_class($callable) . "}->__invoke()";
        }

        return self::value($callable);
    }

    /**
     * @param Exception|Error|Throwable|int $error an Exception, Error (or one of the E_* error severity constants)
     *
     * @return string
     */
    public static function error($error)
    {
        if (is_int($error)) {
            return static::severity($error);
        }

        $type = get_class($error);

        if ($error instanceof ErrorException) {
            $severity = static::severity($error->getSeverity());

            $type = "{$type}: {$severity}";
        }

        if ($error instanceof Exception || $error instanceof Error) {
            $message = $error->getMessage() ?: '{none}';

            $file = $error->getFile()
                ? $error->getFile() . "(" . $error->getLine() . ")"
                : "{no file}";

            return "{$type} with message: {$message} in {$file}";
        }

        return $type;
    }

    /**
     * @param int $severity one of the E_* error severity constants
     *
     * @return string
     */
    public static function severity($severity)
    {
        return isset(self::$severity_names[$severity])
            ? self::$severity_names[$severity]
            : "{unknown error-code}";
    }

    /**
     * @param array|Exception|Error|Throwable $source      Exception, Error or stack-trace data as provided
     *                                                     by Exception::getTrace() or by debug_backtrace()
     * @param bool                            $with_params if TRUE, calls will be formatted with parameters
     *
     * @return string
     */
    public static function trace($source, $with_params = true)
    {
        if ($source instanceof Exception || $source instanceof Error) {
            $trace = $source->getTrace();
        } elseif (is_array($source)) {
            $trace = $source;
        } else {
            return "{stack-trace unavailable}";
        }

        $formatted = [];

        foreach ($trace as $index => $entry) {
            $line = array_key_exists("line", $entry)
                ? ":" . $entry["line"]
                : "";

            $file = isset($entry["file"])
                ? $entry["file"]
                : "{no file}";

            $function = isset($entry["class"])
                ? $entry["class"] . @$entry["type"] . @$entry["function"]
                : @$entry["function"];

            if ($function === "require" || $function === "include") {
                // bypass argument formatting for include and require statements
                $args = isset($entry["args"]) && is_array($entry["args"])
                    ? reset($entry["args"])
                    : "";
            } else {
                $args = $with_params && isset($entry["args"]) && is_array($entry["args"])
                    ? static::values($entry["args"])
                    : "";
            }

            $call = $function
                ? "{$function}({$args})"
                : "";

            $depth = $index + 1;

            $formatted[] = sprintf("%6s", "{$depth}.") . " {$file}{$line} {$call}";
        }

        return implode("\n", $formatted);
    }
}