/*
 * TR8 VM Player
 * Copyright (C) 2023 by Juan J. Martinez <jjm@usebox.net>
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 *
 */

#include <stdio.h>
#include <stdint.h>
#include <string.h>

#include "SDL.h"
#include "opl3.h"

#include "vm.h"

#define ARGB(r, g, b) ((uint32_t)(0xff000000|((r)<<16)|((g)<<8)|(b)))

#define APP_NAME "TR8 VM Player"
#define APP_VERSION "0.1-alpha"

#define TR8_W 128
#define TR8_H 128

#define WINDOW_SCALE 4
#define WINDOW_W (TR8_W * WINDOW_SCALE)
#define WINDOW_H (TR8_H * WINDOW_SCALE)

#define TR8_SAMPLE_RATE     44100
#define TR8_SAMPLE_CHANNELS 1
#define TR8_SAMPLE_SIZE     1024

static void resize_full_screen(SDL_Window *win, SDL_Renderer *renderer, int fullscreen, SDL_Rect *s)
{
    if (!fullscreen)
    {
        SDL_SetWindowFullscreen(win, 0);
        s->x = 0;
        s->y = 0;
        s->w = WINDOW_W;
        s->h = WINDOW_H;
    }
    else
    {
        SDL_SetWindowFullscreen(win, SDL_WINDOW_FULLSCREEN_DESKTOP);

        int sw, sh, w, h, scale;

        SDL_GetRendererOutputSize(renderer, &w, &h);

        sw = w / TR8_W;
        sh = h / TR8_H;
        scale = sw > sh ? sh : sw;

        s->x = (w - (TR8_W * scale)) / 2;
        s->y = (h - (TR8_H * scale)) / 2;
        s->w = TR8_W * scale;
        s->h = TR8_H * scale;
    }
}

static uint32_t palette[] =
{
    ARGB(0x00, 0x00, 0x00),
    ARGB(0x00, 0x00, 0xaa),
    ARGB(0x00, 0xaa, 0x00),
    ARGB(0x00, 0xaa, 0xaa),
    ARGB(0xaa, 0x00, 0x00),
    ARGB(0xaa, 0x00, 0xaa),
    ARGB(0xaa, 0x55, 0x00),
    ARGB(0xaa, 0xaa, 0xaa),
    ARGB(0x55, 0x55, 0x55),
    ARGB(0x55, 0x55, 0xff),
    ARGB(0x55, 0xff, 0x55),
    ARGB(0x55, 0xff, 0xff),
    ARGB(0xff, 0x55, 0x55),
    ARGB(0xff, 0x55, 0xff),
    ARGB(0xff, 0xff, 0x55),
    ARGB(0xff, 0xff, 0xff),
};

uint8_t ram[UINT16_MAX + 1] = { 0 };
uint32_t *fb_data = NULL;

static void update_fb()
{
    for (uint16_t addr = 0; addr < VIDEO_RAM_LEN; addr++)
        fb_data[addr] = palette[ram[VIDEO_RAM + addr] & 15];
}

void write_m(uint16_t addr, uint8_t b)
{
    if (addr >= VIDEO_RAM && addr < VIDEO_RAM + VIDEO_RAM_LEN)
        fb_data[addr - VIDEO_RAM] = palette[b & 15];

    ram[addr] = b;
}

uint8_t read_m(uint16_t addr)
{
    return ram[addr];
}

#define CTL_FIRE1   (1 << 0)
#define CTL_FIRE2   (1 << 1)
#define CTL_UP      (1 << 2)
#define CTL_DOWN    (1 << 3)
#define CTL_LEFT    (1 << 4)
#define CTL_RIGHT   (1 << 5)
#define CTL_SELECT  (1 << 6)
#define CTL_START   (1 << 7)

uint8_t ctl[2] = { 0 };

static void update_ctl(SDL_Event *ev)
{
    switch (ev->key.keysym.sym)
    {
        case SDLK_z:
            ctl[0] = ev->type == SDL_KEYDOWN ? ctl[0] | CTL_FIRE1 : ctl[0] & ~CTL_FIRE1;
            break;
        case SDLK_x:
            ctl[0] = ev->type == SDL_KEYDOWN ? ctl[0] | CTL_FIRE2 : ctl[0] & ~CTL_FIRE2;
            break;
        case SDLK_UP:
            ctl[0] = ev->type == SDL_KEYDOWN ? ctl[0] | CTL_UP : ctl[0] & ~CTL_UP;
            break;
        case SDLK_DOWN:
            ctl[0] = ev->type == SDL_KEYDOWN ? ctl[0] | CTL_DOWN : ctl[0] & ~CTL_DOWN;
            break;
        case SDLK_LEFT:
            ctl[0] = ev->type == SDL_KEYDOWN ? ctl[0] | CTL_LEFT : ctl[0] & ~CTL_LEFT;
            break;
        case SDLK_RIGHT:
            ctl[0] = ev->type == SDL_KEYDOWN ? ctl[0] | CTL_RIGHT : ctl[0] & ~CTL_RIGHT;
            break;
        case SDLK_s:
            ctl[0] = ev->type == SDL_KEYDOWN ? ctl[0] | CTL_START : ctl[0] & ~CTL_START;
            break;
        case SDLK_d:
            ctl[0] = ev->type == SDL_KEYDOWN ? ctl[0] | CTL_SELECT : ctl[0] & ~CTL_SELECT;
            break;
        default:
            break;
    }
}

SDL_mutex *amutex = NULL;

opl3_chip opl;
uint8_t snd_reg[2] = { 0 };

static void audio_callback(void *userdata, uint8_t *stream, int32_t len)
{
    if (!SDL_LockMutex(amutex))
    {
        SDL_memset(stream, 0, len);
        while (len >= 2)
        {
            OPL3_GenerateResampled((opl3_chip *)userdata, (int16_t *)stream);
            stream += 2;
            len -= 2;
        }
        SDL_UnlockMutex(amutex);
    }
}

uint8_t blt_set = 0;
uint8_t blt_paramc = 0;
uint8_t blt_param[6] = { 0 };

uint8_t port(uint8_t p, uint8_t v)
{
    switch (p)
    {
        /* blitter control */
        case 0xb0:
            /* settings mode */
            if (v & 128)
            {
                blt_set = 1;
                blt_paramc = 0;
                return p;
            }
            /* draw (read or write) */
            if (v & 5)
            {
                blt_set = 0;

                /* can't be both */
                if ((v & 1) && (v & 4))
                    return 0xff;

                /* missing parameters */
                if (blt_paramc != 6)
                    return 0xff;

                /* write into vram */
                if (v & 1)
                {
                    uint16_t src = blt_param[0] | (blt_param[1] << 8);

                    for (int16_t y = (int8_t)blt_param[3]; y < (int8_t)blt_param[3] + blt_param[5]; y++)
                        for (int16_t x = (int8_t)blt_param[2]; x < (int8_t)blt_param[2] + blt_param[4]; x++)
                        {
                            uint8_t b = read_m(src++);

                            /* skip transparent if transparent flag is set */
                            if ((v & 2) && (b & 128))
                                continue;

                            /* clipping */
                            if (x < 0 || x >= TR8_W || y < 0 || y >= TR8_H)
                                continue;

                            write_m((uint16_t)(VIDEO_RAM + x + y * 128), b);
                        }
                }
                /* read from vram */
                else
                {
                    uint16_t dst = blt_param[0] | (blt_param[1] << 8);

                    for (int16_t y = (int8_t)blt_param[3]; y < (int8_t)blt_param[3] + blt_param[5]; y++)
                        for (int16_t x = (int8_t)blt_param[2]; x < (int8_t)blt_param[2] + blt_param[4]; x++)
                        {
                            uint8_t b = 0;

                            /* clipping */
                            if (x >= 0 && x < TR8_W  && y >= 0 && y < TR8_H)
                                /* skip transparent if transparent flag is set */
                                if (!((v & 2) && (b & 128)))
                                    b = read_m(VIDEO_RAM + x + y * 128);

                            write_m(dst++, b);
                        }
                }

                return p;
            }
            return 0xff;

        /* blitter settings */
        case 0xb1:
            if (!blt_set || blt_paramc > 5)
                return 0xff;

            blt_param[blt_paramc++] = v;
            return p;

        /* sound register selector primary */
        case 0xc0:
            snd_reg[0] = v & 0xff;
            return p;

        /* sound data primary */
        case 0xc1:
            if (!SDL_LockMutex(amutex))
            {
                OPL3_WriteReg(&opl, snd_reg[0], v);
                SDL_UnlockMutex(amutex);
            }
            return p;

        /* sound register selector secondary */
        case 0xc2:
            snd_reg[1] = v & 0xff;
            return p;

        /* sound data secondary */
        case 0xc3:
            if (!SDL_LockMutex(amutex))
            {
                OPL3_WriteReg(&opl, 0x100 | snd_reg[1], v);
                SDL_UnlockMutex(amutex);
            }
            return p;

        /* controller 1 */
        case 0xf0:
            return ctl[0];

        /* controller 2 */
        case 0xf1:
            return ctl[1];

        default:
            return 0xff;
    }
}

int main(int argc, char *argv[])
{
    FILE *fd;
    size_t size;

    if (argc < 2)
    {
        fprintf(stderr, "Usage: input.prg\n");
        return 1;
    }
    fd = fopen(argv[1], "rb");
    if (!fd)
    {
        fclose(fd);
        fprintf(stderr, "Error opening input\n");
        return 1;
    }
    if (fseek(fd, 0, SEEK_END) == -1)
    {
        fclose(fd);
        fprintf(stderr, "Error opening input\n");
        return 1;
    }
    size = ftell(fd);
    if (size > UINT16_MAX + 1)
    {
        fclose(fd);
        fprintf(stderr, "Input is too large\n");
        return 1;
    }
    fseek(fd, 0, SEEK_SET);
    if (fread(ram, 1, size, fd) != size)
    {
        fclose(fd);
        fprintf(stderr, "Error reading input\n");
        return 1;
    }
    fclose(fd);

    if (SDL_Init(SDL_INIT_VIDEO | SDL_INIT_AUDIO | SDL_INIT_GAMECONTROLLER))
    {
        fprintf(stderr, "Failed init: %s\n", SDL_GetError());
        return 1;
    }

    /* init audio */
    OPL3_Reset(&opl, TR8_SAMPLE_RATE);

    amutex = SDL_CreateMutex();
    if (!amutex)
    {
        fprintf(stderr, "Failed to create mutex: %s\n", SDL_GetError());
        return 1;
    }

    SDL_AudioSpec audio_spec, audio_want;

    SDL_memset(&audio_want, 0, sizeof(audio_want));

    audio_want.freq = TR8_SAMPLE_RATE,
    audio_want.format = AUDIO_S16,
    audio_want.channels = TR8_SAMPLE_CHANNELS,
    audio_want.callback = audio_callback,
    audio_want.userdata = (void *)&opl;
    audio_want.samples = TR8_SAMPLE_SIZE;

    SDL_AudioDeviceID audio = SDL_OpenAudioDevice(NULL, 0, &audio_want, &audio_spec, 0);
    if (audio == 0)
        fprintf(stderr, "Failed to open audio: %s\n", SDL_GetError());
    else
        SDL_PauseAudioDevice(audio, 0);

    SDL_Window *screen = SDL_CreateWindow(APP_NAME " " APP_VERSION,
                                          SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED,
                                          WINDOW_W, WINDOW_H,
                                          SDL_WINDOW_OPENGL);
    if (!screen)
    {
        fprintf(stderr, "Failed to create a window: %s\n", SDL_GetError());
        return 1;
    }

    SDL_Renderer *renderer = SDL_CreateRenderer(screen, -1, SDL_RENDERER_TARGETTEXTURE | SDL_RENDERER_PRESENTVSYNC | SDL_RENDERER_ACCELERATED);
    if (!renderer)
    {
        fprintf(stderr, "Failed to create the renderer: %s\n", SDL_GetError());
        return 1;
    }
    SDL_SetHint("SDL_HINT_RENDER_SCALE_QUALITY", "0");

    SDL_Texture *canvas = SDL_CreateTexture(renderer, SDL_PIXELFORMAT_ARGB8888, SDL_TEXTUREACCESS_TARGET, TR8_W, TR8_H);
    if (!canvas)
    {
        fprintf(stderr, "Failed to create the canvas: %s\n", SDL_GetError());
        return 1;
    }

    SDL_Texture *fb = SDL_CreateTexture(renderer, SDL_PIXELFORMAT_ARGB8888, SDL_TEXTUREACCESS_STREAMING, TR8_W, TR8_H);
    if (!fb)
    {
        fprintf(stderr, "Failed to create the frame-buffer: %s\n", SDL_GetError());
        return 1;
    }
    SDL_SetTextureBlendMode(fb, SDL_BLENDMODE_NONE);

    int fullscreen = 0;
    SDL_Rect dst;
    resize_full_screen(screen, renderer, fullscreen, &dst);

    SDL_SetRenderDrawColor(renderer, 18, 18, 18, 255);
    SDL_RenderClear(renderer);
    SDL_RenderPresent(renderer);

    Tr8 vm;
    tr8_init(&vm, write_m, read_m, port);
    int pitch = 0;
    uint8_t rc;

    /* update full fb once to sync with RAM */
    pitch = 0;
    fb_data = NULL;
    SDL_LockTexture(fb, NULL, (void **)&fb_data, &pitch);
    update_fb();
    SDL_UnlockTexture(fb);

    SDL_Event ev;
    uint8_t quit = 0;

    while (!quit)
    {
        while (SDL_PollEvent(&ev))
        {
            if (ev.type == SDL_QUIT)
                quit = 1;

            if (ev.type == SDL_KEYDOWN)
            {
                if (ev.key.keysym.sym == SDLK_ESCAPE)
                {
                    if (fullscreen)
                        resize_full_screen(screen, renderer, 0, &dst);
                    quit = 1;
                }
                if (ev.key.keysym.sym == SDLK_RETURN && (SDL_GetModState() & KMOD_LALT))
                {
                    fullscreen ^= 1;
                    resize_full_screen(screen, renderer, fullscreen, &dst);
                }
                update_ctl(&ev);
            }

            if (ev.type == SDL_KEYUP)
                update_ctl(&ev);
        }

        pitch = 0;
        fb_data = NULL;
        SDL_LockTexture(fb, NULL, (void **)&fb_data, &pitch);
        rc = tr8_frame_int(&vm);
        if (rc)
            rc = tr8_eval(&vm);
        SDL_UnlockTexture(fb);

        if (!rc)
            break;

        /* render to the canvas */
        SDL_SetRenderTarget(renderer, canvas);
        SDL_RenderClear(renderer);

        SDL_RenderCopy(renderer, fb, NULL, NULL);

        /* now target the screen */
        SDL_SetRenderTarget(renderer, NULL);
        SDL_RenderClear(renderer);
        SDL_RenderCopy(renderer, canvas, NULL, &dst);

        SDL_RenderPresent(renderer);
    }

    if (canvas)
        SDL_DestroyTexture(canvas);
    if (fb)
        SDL_DestroyTexture(fb);

    if (audio > 0)
        SDL_CloseAudioDevice(audio);

    if (amutex)
        SDL_DestroyMutex(amutex);

    SDL_DestroyRenderer(renderer);
    SDL_DestroyWindow(screen);

    return 0;
}