package main

import "github.com/veandco/go-sdl2/sdl"

/*
#cgo CFLAGS: -I/home/nick/Downloads/include
#cgo LDFLAGS: -L/home/nick/.local/lib -lprojectM-4
#include "projectM-4/projectM.h"
#include <stdlib.h>
*/
import "C"

import (
	"encoding/binary"
	"io"
	"os"
	"time"
	"unsafe"
)

func main() {
	windowWidth := 800
	windowHeight := 600

	err := sdl.Init(sdl.INIT_VIDEO)
	if err != nil {
		panic(err)
	}
	defer sdl.Quit()

	window, err := sdl.CreateWindow("milkbucket", sdl.WINDOWPOS_UNDEFINED, sdl.WINDOWPOS_UNDEFINED, int32(windowWidth), int32(windowHeight), sdl.WINDOW_OPENGL)
	if err != nil {
		panic(err)
	}
	defer window.Destroy()

	context, err := window.GLCreateContext()
	if err != nil {
		panic(err)
	}
	defer sdl.GLDeleteContext(context)

	handle := C.projectm_create()
	if handle == nil {
		panic("nil")
	}
	defer C.projectm_destroy(handle)

	C.projectm_set_window_size(handle, C.ulong(windowWidth), C.ulong(windowHeight))

	preset := C.CString("/usr/share/projectM/presets/presets_stock/Zylot - Wisps.milk")
	defer C.free(unsafe.Pointer(preset))
	C.projectm_load_preset_file(handle, preset, false)

	const bufSize uint = 2048

	running := true
	for running {
		for event := sdl.PollEvent(); event != nil; event = sdl.PollEvent() {
			switch event.(type) {
			case *sdl.QuitEvent:
				running = false
				break
			}
		}

		var audioData [bufSize]int16

		err = binary.Read(os.Stdin, binary.LittleEndian, &audioData)
		if err == io.ErrUnexpectedEOF {
			running = false
			break
		} else if err != nil {
			panic(err)
		}

		C.projectm_pcm_add_int16(handle, (*C.int16_t)(&audioData[0]), C.uint(bufSize), C.PROJECTM_STEREO)

		C.projectm_opengl_render_frame(handle)
		window.GLSwap()
		time.Sleep(1 / 60 * time.Second)
	}
}