/**
 *    Copyright (C) 2018-present MongoDB, Inc.
 *
 *    This program is free software: you can redistribute it and/or modify
 *    it under the terms of the Server Side Public License, version 1,
 *    as published by MongoDB, Inc.
 *
 *    This program is distributed in the hope that it will be useful,
 *    but WITHOUT ANY WARRANTY; without even the implied warranty of
 *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *    Server Side Public License for more details.
 *
 *    You should have received a copy of the Server Side Public License
 *    along with this program. If not, see
 *    <http://www.mongodb.com/licensing/server-side-public-license>.
 *
 *    As a special exception, the copyright holders give permission to link the
 *    code of portions of this program with the OpenSSL library under certain
 *    conditions as described in each individual source file and distribute
 *    linked combinations including the program with the OpenSSL library. You
 *    must comply with the Server Side Public License in all respects for
 *    all of the code used other than as permitted herein. If you modify file(s)
 *    with this exception, you may extend this exception to your version of the
 *    file(s), but you are not obligated to do so. If you do not wish to do so,
 *    delete this exception statement from your version. If you delete this
 *    exception statement from all source files in the program, then also delete
 *    it in the license file.
 */

#ifndef UTIL_VERSION_HEADER
#define UTIL_VERSION_HEADER

#include <string>
#include <vector>

#include "mongo/base/string_data.h"
#include "mongo/bson/bsonobj.h"

namespace mongo {

class BSONObjBuilder;

/**
 * An interface for accessing version information about the current process. A singleton instance of
 * this interface is expected to be available via the 'instance' method in processes that need to be
 * able to access version information.
 */
class VersionInfoInterface {
public:
    struct BuildInfoField {
        StringData key;
        StringData value;
        bool inBuildInfo;  // included in buildInfo BSON
        bool inVersion;    // included in --version output
    };

    enum class NotEnabledAction {
        kAbortProcess,
        kFallback,
    };

    VersionInfoInterface(const VersionInfoInterface&) = delete;
    VersionInfoInterface& operator=(const VersionInfoInterface&) = delete;
    virtual ~VersionInfoInterface() = default;

    /**
     * The provided implementation of this interface will be returned by the 'instance' method
     * below. Ownership of the object is not transferred.
     */
    static void enable(const VersionInfoInterface* handler);

    /**
     * Obtain the currently configured instance of the VersionInfoInterface. By default, if this
     * method is called and no implementation has been configured with the 'enable' method above,
     * the process will be terminated. If it is not acceptable to terminate the process, the above
     * 'kFallback' constant can be provided and defaulted information will be provided.
     */
    static const VersionInfoInterface& instance(
        NotEnabledAction action = NotEnabledAction::kAbortProcess) noexcept;

    /**
     * Returns the major version as configured via MONGO_VERSION.
     */
    virtual int majorVersion() const noexcept = 0;

    /**
     * Returns the minor version as configured via MONGO_VERSION.
     */
    virtual int minorVersion() const noexcept = 0;

    /**
     * Returns the patch version as configured via MONGO_VERSION.
     */
    virtual int patchVersion() const noexcept = 0;

    /**
     * Returns the extra version as configured via MONGO_VERSION.
     */
    virtual int extraVersion() const noexcept = 0;

    /**
     * Returns a string representation of MONGO_VERSION.
     */
    virtual StringData version() const noexcept = 0;

    /**
     * Returns a string representation of MONGO_GIT_HASH.
     */
    virtual StringData gitVersion() const noexcept = 0;

    /**
     * Returns a vector describing the enabled modules.
     */
    virtual std::vector<StringData> modules() const = 0;

    /**
     * Returns a string describing the configured memory allocator.
     */
    virtual StringData allocator() const noexcept = 0;

    /**
     * Returns a string describing the configured javascript engine.
     */
    virtual StringData jsEngine() const noexcept = 0;

    /**
     * Returns a string describing the minimum requred OS. Note that this method is currently only
     * valid to call when running on Windows.
     */
    virtual StringData targetMinOS() const noexcept = 0;

    /**
     * Returns build information (e.g. LINKFLAGS, compiler, etc.).
     */
    virtual std::vector<BuildInfoField> buildInfo() const = 0;

    /**
     * Returns the version of OpenSSL in use, if any, adorned with the provided prefix and suffix.
     */
    std::string openSSLVersion(StringData prefix = "", StringData suffix = "") const;

    /**
     * Uses the provided text to make a pretty representation of the version.
     */
    std::string makeVersionString(StringData binaryName) const;

    /**
     * Appends several fields of build information to the `result`. One of them is
     * "buildEnvironment", mapped to a subobject containing most of the information associated
     * with 'buildInfo', above, but with the elements for which inBuildInfo == false
     * removed.
     */
    void appendBuildInfo(BSONObjBuilder* result) const;

    /**
     * Logs the result of 'targetMinOS', above.
     */
    void logTargetMinOS() const;

    /**
     * Logs similar info to `appendBuildInfo`, suitable for the --version flag or for a
     * startup log message (trimmed for user-friendliness). The `buildInfo` data appear
     * in a subobject mapped to the "environment" key, but with the elements for which
     * inVersion == false removed. Puts to `os` if nonnull, else to LOGV2.
     */
    void logBuildInfo(std::ostream* os) const;

protected:
    constexpr VersionInfoInterface() = default;
};

/**
 * Returns a pretty string describing the provided binary's version.
 */
std::string formatVersionString(StringData versioned, const VersionInfoInterface& provider);

/**
 * Returns a pretty string describing the current shell version.
 */
std::string mongoShellVersion(const VersionInfoInterface& provider);

/**
 * Returns a pretty string describing the current mongos version.
 */
std::string mongosVersion(const VersionInfoInterface& provider);

/**
 * Returns a pretty string describing the current mongod version.
 */
std::string mongodVersion(const VersionInfoInterface& provider);

}  // namespace mongo

#endif  // UTIL_VERSION_HEADER