// Copyright 2022 Michael Fisher <mfisher@lvtk.org>
// SPDX-License-Identifier: ISC

#pragma once

#include "lvtk/ext/extension.hpp"

#include <lv2/log/log.h>

namespace lvtk {

/** Wrapper around LV2_Log_Log

    Use this on the stack to log messages
    @headerfile lvtk/ext/log.hpp
    @ingroup utility
 */
struct Logger final : FeatureData<LV2_Log_Log> {
    /** ctor */
    Logger() : FeatureData (LV2_LOG__log) {}

    /** Log a log:Trace message with stream operator */
    inline void operator<< (const std::string& out) const { operator<< (out.c_str()); }

    /** Log log:Trace with stream operator */
    inline void operator<< (const char* out) const {
        if (Trace > 0)
            this->printf (Trace, out);
    }

    /** Log message with va_list

        @param type     LV2_URID type to log
        @param fmt      Format / message
        @param ap       Arguments
    */
    inline int vprintf (uint32_t type, const char* fmt, va_list ap) const {
        if (data != nullptr)
            return data->vprintf (data->handle, type, fmt, ap);
        return 0;
    }

    /** Log message with var args

        @param type     LV2_URID type to log
        @param fmt      Format / message
    */
    inline int printf (uint32_t type, const char* fmt, ...) const {
        va_list argptr;
        va_start (argptr, fmt);
        int res = this->vprintf (type, fmt, argptr);
        va_end (argptr);

        return res;
    }

    /** Assign LV2_URIDs needed to log messages

        @param map  A LV2_URID_Map to inititialize with
     */
    inline void init (LV2_URID_Map* const map) {
        Entry   = map->map (map->handle, LV2_LOG__Entry);
        Error   = map->map (map->handle, LV2_LOG__Error);
        Note    = map->map (map->handle, LV2_LOG__Note);
        Trace   = map->map (map->handle, LV2_LOG__Trace);
        Warning = map->map (map->handle, LV2_LOG__Warning);
    }

private:
    uint32_t Entry   = 0;
    uint32_t Error   = 0;
    uint32_t Note    = 0;
    uint32_t Trace   = 0;
    uint32_t Warning = 0;
};

/** Adds a @ref Logger `log` to your instance.
    
    @tparam Mod Your Plugin or UI type
    
    @ingroup ext
    @headerfile lvtk/ext/log.hpp
*/
template <class Mod>
struct Log : NullExtension {
    /** @private */
    Log (const FeatureList& features) {
        for (const auto& f : features) {
            int n_ok = 0;
            if (strcmp (f.URI, LV2_LOG__log) == 0) {
                _logger.set (f);
                ++n_ok;
            }
            if (strcmp (f.URI, LV2_URID__map) == 0) {
                _logger.init ((LV2_URID_Map*) f.data);
                ++n_ok;
            }
            if (n_ok >= 2)
                break;
        }
    }

    /** Use this logger to log messages with the host. @see Logger */
    Logger& logger() noexcept { return _logger; }

private:
    /** Use this logger to log messages with the host. @see Logger */
    Logger _logger;
};

} // namespace lvtk