package main

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

WINDOW_TITLE :: "PPM Viewer"
WINDOW_X := i32(400)
WINDOW_Y := i32(400)
WINDOW_WIDTH := i32(1024)
WINDOW_HEIGHT := 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)
}


load_ppm :: proc() -> (data: []byte) {
	if len(os.args) > 3 || len(os.args) < 2 {
		print_usage()
	}
	filename := os.args[1]
	//fmt.printfln("filename: %s", filename)

	if !strings.has_suffix(filename, ".ppm") {
		fmt.eprintfln("ERROR: File %s does not have a valid ppm extention (.ppm)", filename)
		os.exit(1)
	}

	//now read file
	succ: bool
	data, succ = os.read_entire_file_from_filename(filename, context.temp_allocator)
	if !succ {
		fmt.eprintfln("ERROR: Failed to load file: %s ", filename)
		os.exit(1)
	}
	return data //don't like naked returns
}

load_ppm_to_rect :: proc() -> (rect: SDL.Rect) {
	if len(os.args) > 3 || len(os.args) < 2 {
		print_usage()
	}
	filename := os.args[1]
	//fmt.printfln("filename: %s", filename)

	if !strings.has_suffix(filename, ".ppm") {
		fmt.eprintfln("ERROR: File %s does not have a valid ppm extention (.ppm)", filename)
		os.exit(1)
	}

	//now read file
	data, succ := os.read_entire_file_from_filename(filename, context.temp_allocator)
	if !succ {
		fmt.eprintfln("ERROR: Failed to load file: %s ", filename)
		os.exit(1)
	}

	it := string(data)
	for line in strings.split_lines_iterator(&it) {
		switch line {
		case "#":
			continue
		//ignore comments
		case "P3":
			fmt.println("has P3")
		case "P6":
			fmt.println("has P6")

		}
	}

	return {0, 0, 0, 0}
}
main :: proc() {
	//first check if the user has provided a ppm file
	load_ppm_to_rect()

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

	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
				}
			}
		}
	}
}