<?php

declare(strict_types=1);

namespace Antlr\Antlr4\Runtime;

/**
 * This class provides access to the current version of the ANTLR 4 runtime
 * library as compile-time and runtime constants, along with methods for
 * checking for matching version numbers and notifying listeners in the case
 * where a version mismatch is detected.
 *
 * The runtime version information is provided by {@see RuntimeMetaData::VERSION} and
 * {@see RuntimeMetaData::getRuntimeVersion()}. Detailed information about these values is
 * provided in the documentation for each member.
 *
 * The runtime version check is implemented by {@see RuntimeMetaData::checkVersion()}. Detailed
 * information about incorporating this call into user code, as well as its use
 * in generated code, is provided in the documentation for the method.</p>
 *
 * Version strings x.y and x.y.z are considered "compatible" and no error
 * would be generated. Likewise, version strings x.y-SNAPSHOT and x.y.z are
 * considered "compatible" because the major and minor components x.y
 * are the same in each.
 *
 * @since 4.3
 */
final class RuntimeMetaData
{
    /**
     * A compile-time constant containing the current version of the ANTLR 4
     * runtime library.
     *
     * This compile-time constant value allows generated parsers and other
     * libraries to include a literal reference to the version of the ANTLR 4
     * runtime library the code was compiled against. At each release, we
     * change this value.
     *
     * Version numbers are assumed to have the form
     * `major.minor.patch.evision-suffix`, with the individual components
     * defined as follows.
     *
     * - major is a required non-negative integer, and is equal to
     * `4 for ANTLR 4.
     * - minor< is a required non-negative integer.
     * - patch is an optional non-negative integer. When `patch` is omitted,
     * the `.` (dot) appearing before it is also omitted.
     * - revision is an optional non-negative integer, and may only be included
     * when `patch` is also included. When `revision` is omitted, the `.` (dot)
     * appearing before it is also omitted.
     * - suffix is an optional string. When `suffix` is omitted, the `-`
     * (hyphen-minus) appearing before it is also omitted.
     */
    public const VERSION = '4.13.2';

    /**
     * Gets the currently executing version of the ANTLR 4 runtime library.
     *
     * This method provides runtime access to the
     * {@see RuntimeMetaData::VERSION} field, as opposed to directly
     * referencing the field as a compile-time constant.</p>
     *
     * @return string The currently executing version of the ANTLR 4 library
     */
    public static function getRuntimeVersion(): string
    {
        return self::VERSION;
    }

    /**
     * This method provides the ability to detect mismatches between the version
     * of ANTLR 4 used to generate a parser, the version of the ANTLR runtime a
     * parser was compiled against, and the version of the ANTLR runtime which
     * is currently executing.
     *
     * The version check is designed to detect the following two specific
     * scenarios.
     *
     * The ANTLR Tool version used for code generation does not match the
     * currently executing runtime version.
     * The ANTLR Runtime version referenced at the time a parser was
     * compiled does not match the currently executing runtime version.
     *
     * Starting with ANTLR 4.3, the code generator emits a call to this method
     * using two constants in each generated lexer and parser: a hard-coded
     * constant indicating the version of the tool used to generate the parser
     * and a reference to the compile-time constant {@link VERSION}. At
     * runtime, this method is called during the initialization of the generated
     * parser to detect mismatched versions, and notify the registered listeners
     * prior to creating instances of the parser.
     *
     * This method does not perform any detection or filtering of semantic
     * changes between tool and runtime versions. It simply checks for a
     * version match and emits an error to stderr if a difference
     * is detected.
     *
     * Note that some breaking changes between releases could result in other
     * types of runtime exceptions, prior to calling this method. In these
     * cases, the underlying version mismatch will not be reported here.
     * This method is primarily intended to notify users of potential
     * semantic changes between releases that do not result in binary
     * compatibility problems which would be detected by the class loader.
     * As with semantic changes, changes that break binary compatibility
     * between releases are mentioned in the release notes accompanying
     * the affected release.
     *
     * *Additional note for target developers:* The version check
     * implemented by this class is designed to address specific compatibility
     * concerns that may arise during the execution of Java applications. Other
     * targets should consider the implementation of this method in the context
     * of that target's known execution environment, which may or may not
     * resemble the design provided for the Java target.
     *
     * @param string $generatingToolVersion The version of the tool used to
     *                                      generate a parser. This value may
     *                                      be null when called from user code
     *                                      that was not generated by, and does
     *                                      not reference, the ANTLR 4 Tool itself.
     * @param string $compileTimeVersion    The version of the runtime the parser
     *                                      was compiled against. This should
     *                                      always be passed using a direct reference
     *                                      to {@see RuntimeMetaData::VERSION}.
     */
    public static function checkVersion(string $generatingToolVersion, string $compileTimeVersion): void
    {
        $runtimeConflictsWithGeneratingTool = $generatingToolVersion !== self::VERSION
            && self::getMajorMinorVersion($generatingToolVersion) !== self::getMajorMinorVersion(self::VERSION);

        $runtimeConflictsWithCompileTimeTool = $compileTimeVersion !== self::VERSION
            && self::getMajorMinorVersion($compileTimeVersion) !== self::getMajorMinorVersion(self::VERSION);

        if ($runtimeConflictsWithGeneratingTool) {
            \trigger_error(
                \sprintf(
                    'ANTLR Tool version %s used for code generation does not ' .
                    'match the current runtime version %s',
                    $generatingToolVersion,
                    self::VERSION,
                ),
                \E_USER_WARNING,
            );
        }

        if ($runtimeConflictsWithCompileTimeTool) {
            \trigger_error(
                \sprintf(
                    'ANTLR Runtime version %s used for parser compilation does not ' .
                    'match the current runtime version %s',
                    $compileTimeVersion,
                    self::VERSION,
                ),
                \E_USER_WARNING,
            );
        }
    }

    /**
     * Gets the major and minor version numbers from a version string. For
     * details about the syntax of the input `version`.
     * E.g., from x.y.z return x.y.
     *
     * @param string $version The complete version string.
     *
     * @return string A string of the form `major`.`minor` containing
     * only the major and minor components of the version string.
     */
    public static function getMajorMinorVersion(string $version): string
    {
        $firstDot = \strpos($version, '.');
        $referenceLength = \strlen($version);
        $secondDot = false;

        if ($firstDot !== false && $firstDot < $referenceLength) {
            $secondDot = \strpos($version, '.', $firstDot + 1);
        }

        $firstDash = \strpos($version, '-');

        if ($secondDot !== false) {
            $referenceLength = \min($secondDot, $secondDot);
        }

        if ($firstDash !== false) {
            $referenceLength = \min($referenceLength, $firstDash);
        }

        return \substr($version, 0, $referenceLength);
    }
}
