const std = @import("std");


const Timestamp = struct {
    hours: u64,
    minutes: u64,
};

const testees:[]const []const u8 = &[_][] const u8 {
    "Gruppe A",
    "Gruppe B",
    "Gruppe C",
    "Gruppe D",
    "Gruppe E",
    "Gruppe F",
    "Gruppe G",
    "Gruppe H",
    "Gruppe I",
    "Gruppe J",
};
const number_of_testees: u64 = testees.len;

const total_minutes: u64 = 190;
const pause_minutes: u64 = 5;


pub fn main () !void {

    var time = Timestamp {
        .hours = 12,
        .minutes = 0,
    };
    
    try printPlan(&time);
}


//? Printet timestamp im Format HH:MM
pub fn printTimestamp(ts: *Timestamp) !void {

    const writer = std.io.getStdOut().writer();

    try writer.print("{0d:0>2}:{1d:0>2}", .{ ts.hours, ts.minutes });
}


//? Add a given minute amount to the given timestamp
pub fn addMinutesToTimestamp(ts: *Timestamp, min: u16) void{

    var addHours: u64 = min / 60;
    var addMinutes: u64 = min%60;

    if ((addMinutes + ts.minutes) >= 60){
        addMinutes = (addMinutes + ts.minutes)%60;
        addHours += 1;
        ts.minutes = 0;
    }

    ts.hours += addHours;
    ts.minutes += addMinutes;
}


//? Print the whole test-plan
pub fn printPlan(ts: *Timestamp) !void {

    const rand = std.crypto.random;
    const writer = std.io.getStdOut().writer();

    //? BLOCK CALCULATION
    const testTime: u64 = total_minutes - ((number_of_testees - 1) * pause_minutes);

    const timePerTest: u64 = testTime / number_of_testees;


    //? CREATE RANDOM ORDER ARRAY 
    const noneNumber:u64 = number_of_testees+1;
    var testees_order: [number_of_testees]u64 = undefined;

    //? Fill order array with noneNumber
    for (testees_order, 0..) |_, index| {
        testees_order[index] = noneNumber;
    }

    //? Fill order array with order until full
    for (testees, 0..) |_, blockIndex| {
        while(true) {
            const randIndex:u64 = rand.intRangeLessThan(u64, 0, number_of_testees);

            if (arrayContains(&testees_order, randIndex)) {
                continue;
            }
            testees_order[blockIndex] = randIndex;
            break;
        }
    }


    //? PLAN OUTPUT
    try writer.print("{d} Gruppen x {d} Minuten ({d} Minuten Pause dazwischen) \n", .{number_of_testees, timePerTest, pause_minutes});
    try writer.print("Beginn des Testat-Termins: ", .{});
    try printTimestamp(ts);
    try writer.print("\n", .{});
    try writer.print("Testat-Bloecke: \n", .{});

    for (testees_order, 0..) |testee, index| {
        try writer.print("{d}.) ", .{index+1});
        try printTimestamp(ts);
        try writer.print("-", .{});
        addMinutesToTimestamp(ts, timePerTest);
        try printTimestamp(ts);
        addMinutesToTimestamp(ts, pause_minutes);
        try writer.print(": {s} \n", .{testees[testee]});
    }
}

//? Check if a given array contains a given element
pub fn arrayContains(arr: []u64, q: u64) bool {
    for (arr) |element| {
        if (element == q) {
            return true;
        }
    }
    return false;
}