const fs = require('fs');
const chalk = require('chalk');

var args = process.argv.slice(2);

function reverseDigitsOf(n) {
    if (n == 0) return [0];
    var a = n;
    digits = [];
    while(a > 0) {
        digits.push(a % 10);
        a = Math.floor(a / 10);
    }
    return digits;
}

function process(intcode,input) {
    var ptr = 0;
    var output = 0;
    while (true) {
        if (intcode[ptr] == 99) break;
        var parts = reverseDigitsOf(intcode[ptr]);
        var opcode = parts[0];
        switch (opcode) {
            // Add
            case 1:
                var a = (parts[2] == 1) ? intcode[ptr+1] : intcode[intcode[ptr+1]];
                var b = (parts[3] == 1) ? intcode[ptr+2] : intcode[intcode[ptr+2]];
                var d = intcode[ptr+3];
                intcode[d] = a + b;
                ptr += 4;
                break;

            // Multiply
            case 2:
                var a = (parts[2] == 1) ? intcode[ptr+1] : intcode[intcode[ptr+1]];
                var b = (parts[3] == 1) ? intcode[ptr+2] : intcode[intcode[ptr+2]];
                var d = intcode[ptr+3];
                intcode[d] = a * b;
                ptr += 4;
                break;

            // Input
            case 3:
                console.log("Input: " + input)
                intcode[intcode[ptr+1]] = input;
                ptr += 2;
                break;

            // Output
            case 4:
                console.log("Output: " + intcode[intcode[ptr+1]]);
                output = intcode[intcode[ptr+1]];
                ptr += 2;
                break;

            // Jump if True
            case 5:
                var a = (parts[2] == 1) ? intcode[ptr+1] : intcode[intcode[ptr+1]];
                var b = (parts[3] == 1) ? intcode[ptr+2] : intcode[intcode[ptr+2]];
                if (a != 0) { ptr = b }
                else { ptr += 3; }
                break;

            // Jump if False
            case 6:
                var a = (parts[2] == 1) ? intcode[ptr+1] : intcode[intcode[ptr+1]];
                var b = (parts[3] == 1) ? intcode[ptr+2] : intcode[intcode[ptr+2]];
                if (a == 0) { ptr = b; }
                else { ptr += 3; }
                break;

            // Less Than
            case 7:
                var a = (parts[2] == 1) ? intcode[ptr+1] : intcode[intcode[ptr+1]];
                var b = (parts[3] == 1) ? intcode[ptr+2] : intcode[intcode[ptr+2]];
                var d = intcode[ptr+3];
                (a < b) ? intcode[d] = 1 : intcode[d] = 0;
                ptr += 4;
                break;

            // Equals
            case 8:
                var a = (parts[2] == 1) ? intcode[ptr+1] : intcode[intcode[ptr+1]];
                var b = (parts[3] == 1) ? intcode[ptr+2] : intcode[intcode[ptr+2]];
                var d = intcode[ptr+3];
                (a == b) ? intcode[d] = 1 : intcode[d] = 0;
                ptr += 4;
                break;

            default:
                console.log("ERROR: Unknown instruction: "+opcode);
                loop = false;
                return;
                break;
        }
    }
    return output;
}

function day05(filename) {

    // Load input
    const input = fs.readFileSync(filename)
        .toString()
        .split(",")
        .map(n => Number(n));

    // Part 1
    var intcode = [...input];
    const part1 = process(intcode,1);

    // Part 2
    intcode = [...input];
    const part2 = process(intcode,5);

    return [part1,part2];
}

const [part1,part2] = day05(args[0]);
console.log(chalk.blue("Part 1: ") + chalk.yellow(part1)); // 7265618
console.log(chalk.blue("Part 2: ") + chalk.yellow(part2)); // 7731427