/*
  Copyright (C) 1997-2024 Sam Lantinga <slouken@libsdl.org>

  This software is provided 'as-is', without any express or implied
  warranty.  In no event will the authors be held liable for any damages
  arising from the use of this software.

  Permission is granted to anyone to use this software for any purpose,
  including commercial applications, and to alter it and redistribute it
  freely.
*/

#define SDL_MAIN_USE_CALLBACKS 1
#include <SDL3/SDL.h>
#include <SDL3/SDL_main.h>
#include <SDL3/SDL_test.h>

static SDL_Window *window = NULL;
static SDL_Renderer *renderer = NULL;
static SDL_AudioStream *stream_in = NULL;
static SDL_AudioStream *stream_out = NULL;
static SDLTest_CommonState *state = NULL;

int SDL_AppInit(void **appstate, int argc, char **argv)
{
    SDL_AudioDeviceID *devices;
    SDL_AudioSpec outspec;
    SDL_AudioSpec inspec;
    SDL_AudioDeviceID device;
    SDL_AudioDeviceID want_device = SDL_AUDIO_DEVICE_DEFAULT_CAPTURE;
    const char *devname = NULL;
    int i;

    /* this doesn't have to run very much, so give up tons of CPU time between iterations. */
    SDL_SetHint(SDL_HINT_MAIN_CALLBACK_RATE, "15");

    /* Initialize test framework */
    state = SDLTest_CommonCreateState(argv, 0);
    if (!state) {
        return 1;
    }

    /* Enable standard application logging */
    SDL_LogSetPriority(SDL_LOG_CATEGORY_APPLICATION, SDL_LOG_PRIORITY_INFO);

    /* Parse commandline */
    for (i = 1; i < argc;) {
        int consumed;

        consumed = SDLTest_CommonArg(state, i);
        if (!consumed) {
            if (!devname) {
                devname = argv[i];
                consumed = 1;
            }
        }
        if (consumed <= 0) {
            static const char *options[] = { "[device_name]", NULL };
            SDLTest_CommonLogUsage(state, argv[0], options);
            return -1;
        }

        i += consumed;
    }

    /* Load the SDL library */
    if (SDL_Init(SDL_INIT_VIDEO | SDL_INIT_AUDIO) < 0) {
        SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Couldn't initialize SDL: %s\n", SDL_GetError());
        return 1;
    }

    if (SDL_CreateWindowAndRenderer("testaudiocapture", 320, 240, 0, &window, &renderer) < 0) {
        SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Couldn't create SDL window and renderer: %s\n", SDL_GetError());
        return 1;
    }
    SDL_SetRenderDrawColor(renderer, 0, 0, 0, 255);
    SDL_RenderClear(renderer);
    SDL_RenderPresent(renderer);

    SDL_Log("Using audio driver: %s\n", SDL_GetCurrentAudioDriver());

    devices = SDL_GetAudioCaptureDevices(NULL);
    for (i = 0; devices[i] != 0; i++) {
        char *name = SDL_GetAudioDeviceName(devices[i]);
        SDL_Log(" Capture device #%d: '%s'\n", i, name);
        if (devname && (SDL_strcmp(devname, name) == 0)) {
            want_device = devices[i];
        }
        SDL_free(name);
    }

    if (devname && (want_device == SDL_AUDIO_DEVICE_DEFAULT_CAPTURE)) {
        SDL_LogWarn(SDL_LOG_CATEGORY_APPLICATION, "Didn't see a capture device named '%s', using the system default instead.\n", devname);
        devname = NULL;
    }

    /* DirectSound can fail in some instances if you open the same hardware
       for both capture and output and didn't open the output end first,
       according to the docs, so if you're doing something like this, always
       open your capture devices second in case you land in those bizarre
       circumstances. */

    SDL_Log("Opening default playback device...\n");
    device = SDL_OpenAudioDevice(SDL_AUDIO_DEVICE_DEFAULT_OUTPUT, NULL);
    if (!device) {
        SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Couldn't open an audio device for playback: %s!\n", SDL_GetError());
        return -1;
    }
    SDL_PauseAudioDevice(device);
    SDL_GetAudioDeviceFormat(device, &outspec, NULL);
    stream_out = SDL_CreateAudioStream(&outspec, &outspec);
    if (!stream_out) {
        SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Couldn't create an audio stream for playback: %s!\n", SDL_GetError());
        return -1;
    } else if (SDL_BindAudioStream(device, stream_out) == -1) {
        SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Couldn't bind an audio stream for playback: %s!\n", SDL_GetError());
        return -1;
    }

    SDL_Log("Opening capture device %s%s%s...\n",
            devname ? "'" : "",
            devname ? devname : "[[default]]",
            devname ? "'" : "");

    device = SDL_OpenAudioDevice(want_device, NULL);
    if (!device) {
        SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Couldn't open an audio device for capture: %s!\n", SDL_GetError());
        return -1;
    }
    SDL_PauseAudioDevice(device);
    SDL_GetAudioDeviceFormat(device, &inspec, NULL);
    stream_in = SDL_CreateAudioStream(&inspec, &inspec);
    if (!stream_in) {
        SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Couldn't create an audio stream for capture: %s!\n", SDL_GetError());
        return -1;
    } else if (SDL_BindAudioStream(device, stream_in) == -1) {
        SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Couldn't bind an audio stream for capture: %s!\n", SDL_GetError());
        return -1;
    }

    SDL_SetAudioStreamFormat(stream_in, NULL, &outspec);  /* make sure we output at the playback format. */

    SDL_Log("Ready! Hold down mouse or finger to record!\n");

    return 0;
}

int SDL_AppEvent(void *appstate, const SDL_Event *event)
{
    if (event->type == SDL_EVENT_QUIT) {
        return 1;  /* terminate as success. */
    } else if (event->type == SDL_EVENT_KEY_DOWN) {
        if (event->key.keysym.sym == SDLK_ESCAPE) {
            return 1;  /* terminate as success. */
        }
    } else if (event->type == SDL_EVENT_MOUSE_BUTTON_DOWN) {
        if (event->button.button == 1) {
            SDL_PauseAudioDevice(SDL_GetAudioStreamDevice(stream_out));
            SDL_FlushAudioStream(stream_out);  /* so no samples are held back for resampling purposes. */
            SDL_ResumeAudioDevice(SDL_GetAudioStreamDevice(stream_in));
        }
    } else if (event->type == SDL_EVENT_MOUSE_BUTTON_UP) {
        if (event->button.button == 1) {
            SDL_PauseAudioDevice(SDL_GetAudioStreamDevice(stream_in));
            SDL_FlushAudioStream(stream_in);  /* so no samples are held back for resampling purposes. */
            SDL_ResumeAudioDevice(SDL_GetAudioStreamDevice(stream_out));
        }
    }
    return 0;  /* keep going. */
}

int SDL_AppIterate(void *appstate)
{
    if (!SDL_AudioDevicePaused(SDL_GetAudioStreamDevice(stream_in))) {
        SDL_SetRenderDrawColor(renderer, 0, 255, 0, 255);
    } else {
        SDL_SetRenderDrawColor(renderer, 255, 0, 0, 255);
    }
    SDL_RenderClear(renderer);
    SDL_RenderPresent(renderer);

    /* Feed any new data we captured to the output stream. It'll play when we unpause the device. */
    while (SDL_GetAudioStreamAvailable(stream_in) > 0) {
        Uint8 buf[1024];
        const int br = SDL_GetAudioStreamData(stream_in, buf, sizeof(buf));
        if (br < 0) {
            SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Failed to read from input audio stream: %s\n", SDL_GetError());
            return -1;   /* quit the app, report failure. */
        } else if (SDL_PutAudioStreamData(stream_out, buf, br) < 0) {
            SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Failed to write to output audio stream: %s\n", SDL_GetError());
            return -1;   /* quit the app, report failure. */
        }
    }

    return 0;  /* keep app going. */
}

void SDL_AppQuit(void *appstate)
{
    SDL_Log("Shutting down.\n");
    const SDL_AudioDeviceID devid_in = SDL_GetAudioStreamDevice(stream_in);
    const SDL_AudioDeviceID devid_out = SDL_GetAudioStreamDevice(stream_out);
    SDL_CloseAudioDevice(devid_in);  /* !!! FIXME: use SDL_OpenAudioDeviceStream instead so we can dump this. */
    SDL_CloseAudioDevice(devid_out);
    SDL_DestroyAudioStream(stream_in);
    SDL_DestroyAudioStream(stream_out);
    SDL_DestroyRenderer(renderer);
    SDL_DestroyWindow(window);
    SDLTest_CommonDestroyState(state);
    SDL_Quit();
}