package main

import "core:fmt"
import "core:os"
import SDL "vendor:sdl2"

WINDOW_TITLE :: "PPM Viewer"
WINDOW_X := i32(400)
WINDOW_Y := i32(400)
WINDOW_WIDTH_MIN := i32(920)
WINDOW_HEIGHT_MIN := i32(920)
WINDOW_FLAGS :: SDL.WindowFlags{.SHOWN, .RESIZABLE, .ALWAYS_ON_TOP}

print_usage :: proc() {
	fmt.printfln("Usage:\n\t%s [ppm file]", os.args[0])
	os.exit(1)
}


main :: proc() {
	file := Ppm_file{}

	if len(os.args) > 3 || len(os.args) < 2 {
		print_usage()
	}
	filename := os.args[1]
	success := load_ppm(&file, filename)

	if !success {
		fmt.eprintfln("Could not load file %s", filename)
		os.exit(1)
	}
	ppm_parse(&file)

	window_width: i32 = i32(
		file.width,
	); if i32(file.width) < WINDOW_WIDTH_MIN {window_width = WINDOW_WIDTH_MIN}
	window_height: i32 = i32(
		file.width,
	); if i32(file.height) < WINDOW_WIDTH_MIN {window_height = WINDOW_HEIGHT_MIN}

	sdl_init_error := SDL.Init(SDL.INIT_VIDEO)
	assert(sdl_init_error == 0, SDL.GetErrorString())

	defer SDL.Quit()
	window := SDL.CreateWindow(
		WINDOW_TITLE,
		SDL.WINDOWPOS_CENTERED,
		SDL.WINDOWPOS_CENTERED,
		window_width,
		window_height,
		WINDOW_FLAGS,
	)

	assert(window != nil, SDL.GetErrorString())
	defer SDL.DestroyWindow(window)

	surface := SDL.GetWindowSurface(window)

	colour_bg := SDL.MapRGB(surface.format, 42, 42, 42)
	SDL.FillRect(surface, nil, colour_bg)

	i := 0
	pixel := SDL.Rect{0, 0, 1, 1}

	for y: i32 = 0; y < i32(file.height); y += 1 {
		for x: i32 = 0; x < i32(file.width); x += 1 {
			red: u8
			green: u8
			blue: u8
			red = file.pixels[i].red
			green = file.pixels[i].green
			blue = file.pixels[i].blue
			pixel.x = x
			pixel.y = y

			SDL.FillRect(surface, &pixel, SDL.MapRGB(surface.format, red, green, blue))
			i += 1
		}
	}
	SDL.UpdateWindowSurface(window)

	//Loop!
	quit := false
	e: SDL.Event
	for (!quit) {
		for SDL.PollEvent(&e) {
			#partial switch (e.type) {
			case .QUIT:
				quit = true
			case .KEYDOWN:
				#partial switch (e.key.keysym.sym) {
				case .ESCAPE:
					quit = true
				}
			}
		}
	}
}