use std::collections::VecDeque;
use itertools::Itertools;

fn main() {
    let program = vec![3,8,1001,8,10,8,105,1,0,0,21,38,63,88,97,118,199,280,361,442,99999,3,9,1002,9,3,9,101,2,9,9,1002,9,4,9,4,9,99,3,9,101,3,9,9,102,5,9,9,101,3,9,9,1002,9,3,9,101,3,9,9,4,9,99,3,9,1002,9,2,9,1001,9,3,9,102,3,9,9,101,2,9,9,1002,9,4,9,4,9,99,3,9,102,2,9,9,4,9,99,3,9,102,4,9,9,101,5,9,9,102,2,9,9,101,5,9,9,4,9,99,3,9,1002,9,2,9,4,9,3,9,101,1,9,9,4,9,3,9,102,2,9,9,4,9,3,9,101,1,9,9,4,9,3,9,101,2,9,9,4,9,3,9,1001,9,2,9,4,9,3,9,102,2,9,9,4,9,3,9,102,2,9,9,4,9,3,9,101,1,9,9,4,9,3,9,102,2,9,9,4,9,99,3,9,101,1,9,9,4,9,3,9,102,2,9,9,4,9,3,9,1001,9,2,9,4,9,3,9,1001,9,2,9,4,9,3,9,1001,9,1,9,4,9,3,9,1001,9,1,9,4,9,3,9,1001,9,2,9,4,9,3,9,102,2,9,9,4,9,3,9,1002,9,2,9,4,9,3,9,1001,9,1,9,4,9,99,3,9,1002,9,2,9,4,9,3,9,1002,9,2,9,4,9,3,9,102,2,9,9,4,9,3,9,1002,9,2,9,4,9,3,9,1001,9,1,9,4,9,3,9,102,2,9,9,4,9,3,9,102,2,9,9,4,9,3,9,101,1,9,9,4,9,3,9,102,2,9,9,4,9,3,9,102,2,9,9,4,9,99,3,9,102,2,9,9,4,9,3,9,101,1,9,9,4,9,3,9,1002,9,2,9,4,9,3,9,1002,9,2,9,4,9,3,9,102,2,9,9,4,9,3,9,1002,9,2,9,4,9,3,9,1001,9,2,9,4,9,3,9,101,2,9,9,4,9,3,9,1001,9,2,9,4,9,3,9,101,1,9,9,4,9,99,3,9,101,1,9,9,4,9,3,9,101,1,9,9,4,9,3,9,101,1,9,9,4,9,3,9,102,2,9,9,4,9,3,9,1001,9,1,9,4,9,3,9,1001,9,2,9,4,9,3,9,101,2,9,9,4,9,3,9,102,2,9,9,4,9,3,9,1001,9,1,9,4,9,3,9,1001,9,2,9,4,9,99];

    let mut max_storage = 0;
    let mut max_settings: Vec<i32> = Vec::new();

    {
        let settings = vec![0, 1, 2, 3, 4];
        // Cheese.
        for permutation in settings.into_iter().permutations(5) {
            //println!("{:?}", permutation);
            let storage = run_amplifiers(&program, permutation.clone());
            if storage > max_storage {
                max_storage = storage;
                max_settings = permutation.clone();
            }
        }
        println!("[Part 1] Settings {:?} produced a value of {}", max_settings, max_storage);
    }

    {
        let settings = vec![5, 6, 7, 8, 9];
        for permutation in settings.into_iter().permutations(5) {
            let storage = run_feedback_amplifiers(&program, permutation.clone());
            if storage > max_storage {
                max_storage = storage;
                max_settings = permutation.clone();
            }
        }
        println!("[Part 2] Settings {:?} produced a value of {}", max_settings, max_storage);
    }
}

fn run_amplifiers(program: &Vec<i32>, settings: Vec<i32>) -> i32 {
    let mut storage: i32 = 0;
    for setting in settings {
        let mut input = VecDeque::from([setting, storage]);
        let mut output: Vec<i32> = Vec::new();
        icc::simulate(&mut program.clone(), &mut input, &mut output, 0);
        storage = output[0];
    }
    return storage;
}

fn run_feedback_amplifiers(program: &Vec<i32>, settings: Vec<i32>) -> i32 {
    let amplifiers = [
        // program, input signal, entrypoint, setting
        (&mut program.clone(), &mut 0, &mut 0usize, &mut icc::Status::Running),
        (&mut program.clone(), &mut 0, &mut 0usize, &mut icc::Status::Running),
        (&mut program.clone(), &mut 0, &mut 0usize, &mut icc::Status::Running),
        (&mut program.clone(), &mut 0, &mut 0usize, &mut icc::Status::Running),
        (&mut program.clone(), &mut 0, &mut 0usize, &mut icc::Status::Running),
    ];
    let mut iter: i32 = 0;
    loop {
        for (index, setting) in settings.iter().enumerate() {
            match amplifiers[index].3 {
                icc::Status::Finished => {
                    if index == 4 {
                        // the output of amplifier 4 is stored on the input of amplifier 0
                        return *amplifiers[0].1;
                    }
                    continue;
                },
                _ => {}
            }
            println!("[Iter {}] Running amplifier {} from instruction {}", iter, index, *amplifiers[index].2);
            let mut input = if iter == 0 {
                VecDeque::from([*setting, *amplifiers[index].1])
            } else {
                VecDeque::from([*amplifiers[index].1])
            };
            let mut output: Vec<i32> = Vec::new();
            let result = icc::simulate(amplifiers[index].0, &mut input, &mut output, *amplifiers[index].2);
            match result.status {
                icc::Status::WaitingForInput => {
                    println!("[Iter {}] Amplifier {} is waiting for input", iter, index);
                },
                _ => {},
            }
            let amp_index = (index+1) % settings.len();
            *amplifiers[amp_index].1 = output[0];
            println!("[Iter {}] Amplifier {}->{}: {}", iter, index, amp_index, output[0]);
            *amplifiers[index].2 = result.instruction;
            *amplifiers[index].3 = result.status;
        }
        iter += 1;
    }
}

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

    #[test]
    fn example_1() {
        let program = vec![3,15,3,16,1002,16,10,16,1,16,15,15,4,15,99,0,0];
        let settings = vec![4, 3, 2, 1, 0];
        assert_eq!(run_amplifiers(&program, settings), 43210);
    }

    #[test]
    fn example_2() {
        let program = vec![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];
        let settings = vec![0,1,2,3,4];
        assert_eq!(run_amplifiers(&program, settings), 54321);
    }

    #[test]
    fn example_3() {
        let program = vec![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];
        let settings = vec![1,0,4,3,2];
        assert_eq!(run_amplifiers(&program, settings), 65210);
    }

    #[test]
    fn part2_example_1() {
        let program = vec![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];
        let settings = vec![9,8,7,6,5];
        assert_eq!(run_feedback_amplifiers(&program, settings), 139629729);
    }

    #[test]
    fn part2_example_2() {
        let program = vec![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];
        let settings = vec![9,7,8,5,6];
        assert_eq!(run_feedback_amplifiers(&program, settings), 18216);
    }
}