use shared::intcode::{IntCode, SimulateStep, CELL};

pub fn run_stages(ic: &IntCode, phases: &[CELL]) -> CELL {
	let mut value = 0;
	for ndx in 0..5 {
		let mut stage = ic.clone();
		stage.next_input = Some(phases[ndx]);
		stage.simulate_step().expect_wait_for_input();
		stage.next_input = Some(value);
		value = stage.simulate_step().expect_output();
		stage.simulate_step().expect_finished();
	}
	value
}

pub fn run_feedback_stages(ic: &IntCode, phases: &[CELL]) -> CELL {
	let mut stages = [ ic.clone(), ic.clone(), ic.clone(), ic.clone(), ic.clone() ];
	// init all with phase
	for ndx in 0..5 {
		stages[ndx].next_input = Some(phases[ndx]);
		stages[ndx].simulate_step().expect_wait_for_input();
	}

	let mut output = 0;
	stages[0].next_input = Some(output);
	let mut current_ndx = 0;
	loop {
		match stages[current_ndx].simulate_step() {
			SimulateStep::Output(v) => {
				current_ndx = (current_ndx + 1) % 5;
				stages[current_ndx].next_input = Some(v);
				if current_ndx == 0 {
					// remember last final output
					output = v;
				}
			},
			SimulateStep::WaitForInput => {
				panic!("Can't wait for new input before generating one");
			},
			SimulateStep::Finished => break,
		}
	}

	assert_eq!(current_ndx, 0, "first amplifiert should be first to stop");
	for ndx in current_ndx+1..5 {
		stages[ndx].simulate_step().expect_finished();
	}

	output
}

pub fn best_amplifier(ic: &IntCode) -> (Vec<CELL>, CELL) {
	use itertools::Itertools;
	(0..5).permutations(5).map(|phases| {
		let value = run_stages(ic, &phases);
		(phases, value)
	}).max_by_key(|(_, value)| *value).unwrap()
}

pub fn best_feedback_amplifier(ic: &IntCode) -> (Vec<CELL>, CELL) {
	use itertools::Itertools;
	(5..10).permutations(5).map(|phases| {
		let value = run_feedback_stages(ic, &phases);
		(phases, value)
	}).max_by_key(|(_, value)| *value).unwrap()
}

fn main() {
	let ic = include_str!("input.txt").parse::<IntCode>().unwrap();

	let (phases, max_value) = best_amplifier(&ic);
	println!("Max Value: {} (from phases: {:?}", max_value, phases);

	let (phases, max_value) = best_feedback_amplifier(&ic);
	println!("Max Feedback Value: {} (from phases: {:?}", max_value, phases);
}

#[cfg(test)]
mod day7test {
	use super::*;

	#[test]
	fn examples1() {
		assert_eq!(best_amplifier(&"3,15,3,16,1002,16,10,16,1,16,15,15,4,15,99,0,0".parse::<IntCode>().unwrap()), (vec![4,3,2,1,0], 43210));
		assert_eq!(best_amplifier(&"3,23,3,24,1002,24,10,24,1002,23,-1,23,101,5,23,23,1,24,23,23,4,23,99,0,0".parse::<IntCode>().unwrap()), (vec![0,1,2,3,4], 54321));
		assert_eq!(best_amplifier(&"3,31,3,32,1002,32,10,32,1001,31,-2,31,1007,31,0,33,1002,33,7,33,1,33,31,31,1,32,31,31,4,31,99,0,0,0".parse::<IntCode>().unwrap()), (vec![1,0,4,3,2], 65210));
	}

	#[test]
	fn examples2() {
		assert_eq!(best_feedback_amplifier(&"3,26,1001,26,-4,26,3,27,1002,27,2,27,1,27,26,27,4,27,1001,28,-1,28,1005,28,6,99,0,0,5".parse::<IntCode>().unwrap()), (vec![9,8,7,6,5], 139629729));
		assert_eq!(best_feedback_amplifier(&"3,52,1001,52,-5,52,3,53,1,52,56,54,1007,54,5,55,1005,55,26,1001,54,-5,54,1105,1,12,1,53,54,53,1008,54,0,55,1001,55,1,55,2,53,55,53,4,53,1001,56,-1,56,1005,56,6,99,0,0,0,0,10".parse::<IntCode>().unwrap()), (vec![9,7,8,5,6], 18216));
	}
}