use std::{env, time};
use time::Instant;

use opencv::core::Size;
use opencv::prelude::*;
use opencv::{core, imgcodecs, imgproc, Result};

const ITERATIONS: usize = 100;

fn main() -> Result<()> {
	let img_file = env::args().nth(1).expect("Please supply image file name");

	let dev_count = core::get_cuda_enabled_device_count()?;
	let cuda_available = dev_count > 0;
	if cuda_available {
		for dev_num in 0..dev_count {
			core::print_short_cuda_device_info(dev_num)?;
		}
	}
	println!(
		"CUDA is {}",
		if cuda_available {
			"available"
		} else {
			"not available"
		}
	);
	println!("Timing CPU implementation... ");
	let img = imgcodecs::imread_def(&img_file)?;
	let start = Instant::now();
	for _ in 0..ITERATIONS {
		let mut gray = Mat::default();
		imgproc::cvt_color_def(&img, &mut gray, imgproc::COLOR_BGR2GRAY)?;
		let mut blurred = Mat::default();
		imgproc::gaussian_blur_def(&gray, &mut blurred, Size::new(7, 7), 1.5)?;
		let mut edges = Mat::default();
		imgproc::canny_def(&blurred, &mut edges, 0., 50.)?;
	}
	println!("{:#?}", start.elapsed());
	#[cfg(all(ocvrs_has_module_cudafilters, ocvrs_has_module_cudaimgproc))]
	if cuda_available {
		use opencv::core::GpuMat;
		use opencv::{cudafilters, cudaimgproc};

		println!("Timing CUDA implementation... ");
		let img = imgcodecs::imread_def(&img_file)?;
		let mut img_gpu = GpuMat::new_def()?;
		img_gpu.upload(&img)?;
		let mut stream = core::Stream::default()?;
		let start = Instant::now();
		for _ in 0..ITERATIONS {
			let mut gray = GpuMat::new_def()?;
			cudaimgproc::cvt_color(&img_gpu, &mut gray, imgproc::COLOR_BGR2GRAY, 0, &mut stream)?;
			let mut blurred = GpuMat::new_def()?;
			let mut filter = cudafilters::create_gaussian_filter_def(gray.typ()?, blurred.typ()?, Size::new(7, 7), 1.5)?;
			filter.apply(&gray, &mut blurred, &mut stream)?;
			let mut edges = GpuMat::new_def()?;
			let mut detector = cudaimgproc::create_canny_edge_detector_def(0., 50.)?;
			detector.detect(&blurred, &mut edges, &mut stream)?;
			stream.wait_for_completion()?;
		}
		println!("{:#?}", start.elapsed());
	}
	Ok(())
}