const input = @embedFile("input1");
const std = @import("std");

pub fn main() !void{
    var increments: usize = 0;
    var t = std.mem.tokenize(u8, input, "\n");

    var window = .{        
        try std.fmt.parseInt(usize, t.next().?, 10),
        try std.fmt.parseInt(usize, t.next().?, 10),
        try std.fmt.parseInt(usize, t.next().?, 10),
    };

    while(t.next())|line|{
        var sum1: usize = window[0] + window[1] + window[2];
        
        window[0] = window[1];
        window[1] = window[2];
        window[2] = try std.fmt.parseInt(usize, line, 10);
        var sum2: usize = window[0] + window[1] + window[2];

        if ( sum1 < sum2) increments += 1;

    }

    std.debug.print("result: {}", .{increments});
}



test "part1" {
    var t = std.mem.tokenize(u8, input, "\n");

    var last: usize = std.math.maxInt(usize);
    var increments: usize = 0;

    while(t.next()) |line| {
        const n = try std.fmt.parseInt(usize, line, 10);
        defer last = n;
        if ( n > last) increments += 1;
    }

    try std.testing.expect(1583 == increments);

}

test "part2"{
    var increments: usize = 0;
    var t = std.mem.tokenize(u8, input, "\n");

    // Read the first window
    var window = .{        
        try std.fmt.parseInt(usize, t.next().?, 10),
        try std.fmt.parseInt(usize, t.next().?, 10),
        try std.fmt.parseInt(usize, t.next().?, 10),
    };

    while(t.next())|line|{
        //with this window, calculate the current window sum
        var sum1: usize = window[0] + window[1] + window[2];
        
        //slide window one over
        window[0] = window[1];
        window[1] = window[2];
        window[2] = try std.fmt.parseInt(usize, line, 10);

        var sum2: usize = window[0] + window[1] + window[2];

        if ( sum1 < sum2){
            increments += 1;
        } 

    }

    std.testing.expect(1627 == increments);
}