/* Copyright (c) 2020, Peter Barrett
**
** Permission to use, copy, modify, and/or distribute this software for
** any purpose with or without fee is hereby granted, provided that the
** above copyright notice and this permission notice appear in all copies.
**
** THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL
** WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED
** WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR
** BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES
** OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
** WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
** ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
** SOFTWARE.
*/

#include "esp_system.h"
#include "esp_int_wdt.h"
#include "esp_spiffs.h"

#define PERF  // some stats about where we spend our time
#include "src/emu.h"
#include "src/video_out.h"

// esp_8_bit
// Atari 8 computers, NES and SMS game consoles on your TV with nothing more than a ESP32 and a sense of nostalgia
// Supports NTSC/PAL composite video, Bluetooth Classic keyboards and joysticks

//  Choose one of the video standards: PAL,NTSC
#define VIDEO_STANDARD NTSC

//  Choose one of the following emulators: EMU_NES,EMU_SMS,EMU_ATARI
#define EMULATOR EMU_ATARI

//  Many emus work fine on a single core (S2), file system access can cause a little flickering
//  #define SINGLE_CORE

// The filesystem should contain folders named for each of the emulators i.e.
//    atari800
//    nofrendo
//    smsplus
// Folders will be auto-populated on first launch with a built in selection of sample media.
// Use 'ESP32 Sketch Data Upload' from the 'Tools' menu to copy a prepared data folder to ESP32

// Create a new emulator, messy ifdefs ensure that only one links at a time
Emu* NewEmulator()
{  
  #if (EMULATOR==EMU_NES)
  return NewNofrendo(VIDEO_STANDARD);
  #endif
  #if (EMULATOR==EMU_SMS)
  return NewSMSPlus(VIDEO_STANDARD);
  #endif
  #if (EMULATOR==EMU_ATARI)
  return NewAtari800(VIDEO_STANDARD);
  #endif
  printf("Must choose one of the following emulators: EMU_NES,EMU_SMS,EMU_ATARI\n");
}

Emu* _emu = 0;            // emulator running on core 0
uint32_t _frame_time = 0;
uint32_t _drawn = 1;
bool _inited = false;

void emu_init()
{
    std::string folder = "/" + _emu->name;
    gui_start(_emu,folder.c_str());
    _drawn = _frame_counter;
}

void emu_loop()
{
    // wait for blanking before drawing to avoid tearing
    video_sync();

    // Draw a frame, update sound, process hid events
    uint32_t t = xthal_get_ccount();
    gui_update();
    _frame_time = xthal_get_ccount() - t;
    _lines = _emu->video_buffer();
    _drawn++;
}

// dual core mode runs emulator on comms core
void emu_task(void* arg)
{
    printf("emu_task %s running on core %d at %dmhz\n",
      _emu->name.c_str(),xPortGetCoreID(),rtc_clk_cpu_freq_value(rtc_clk_cpu_freq_get()));
    emu_init();
    for (;;)
      emu_loop();
}

esp_err_t mount_filesystem()
{
  printf("\n\n\nesp_8_bit\n\nmounting spiffs (will take ~15 seconds if formatting for the first time)....\n");
  uint32_t t = millis();
  esp_vfs_spiffs_conf_t conf = {
    .base_path = "",
    .partition_label = NULL,
    .max_files = 5,
    .format_if_mount_failed = true  // force?
  };
  esp_err_t e = esp_vfs_spiffs_register(&conf);
  if (e != 0)
    printf("Failed to mount or format filesystem: %d. Use 'ESP32 Sketch Data Upload' from 'Tools' menu\n",e);
  vTaskDelay(1);
  printf("... mounted in %d ms\n",millis()-t);
  return e;
}

void setup()
{ 
  rtc_clk_cpu_freq_set(RTC_CPU_FREQ_240M);  
  mount_filesystem();                       // mount the filesystem!
  _emu = NewEmulator();                     // create the emulator!
  hid_init("emu32");                        // bluetooth hid on core 1!

  #ifdef SINGLE_CORE
  emu_init();
  video_init(_emu->cc_width,_emu->flavor,_emu->composite_palette(),_emu->standard); // start the A/V pump on app core
  #else
  xTaskCreatePinnedToCore(emu_task, "emu_task", EMULATOR == EMU_NES ? 5*1024 : 3*1024, NULL, 0, NULL, 0); // nofrendo needs 5k word stack, start on core 0
  #endif
}

#ifdef PERF
void perf()
{
  static int _next = 0;
  if (_drawn >= _next) {
    float elapsed_us = 120*1000000/(_emu->standard ? 60 : 50);
    _next = _drawn + 120;
    
    printf("frame_time:%d drawn:%d displayed:%d blit_ticks:%d->%d, isr time:%2.2f%%\n",
      _frame_time/240,_drawn,_frame_counter,_blit_ticks_min,_blit_ticks_max,(_isr_us*100)/elapsed_us);
      
    _blit_ticks_min = 0xFFFFFFFF;
    _blit_ticks_max = 0;
    _isr_us = 0;
  }
}
#else
void perf(){};
#endif

// this loop always runs on app_core (1).
void loop()
{    
  #ifdef SINGLE_CORE
  emu_loop();
  #else
  // start the video after emu has started
  if (!_inited) {
    if (_lines) {
      printf("video_init\n");
      video_init(_emu->cc_width,_emu->flavor,_emu->composite_palette(),_emu->standard); // start the A/V pump
      _inited = true;
    } else {
      vTaskDelay(1);
    }
  }
  #endif
  
  // update the bluetooth edr/hid stack
  hid_update();

  // Dump some stats
  perf();
}