const std = @import("std");
const c = @cImport(@cInclude("pgcd.c")); // No need to have a .h

pub fn main() !void {
    var gpa = std.heap.GeneralPurposeAllocator(.{}){};
    defer _ = gpa.deinit();
    const allocator = gpa.allocator();
    const args = try std.process.argsAlloc(allocator);
    defer std.process.argsFree(allocator, args);
    if (args.len != 3) {
        std.debug.print("Usage: find-pgcd L R\n", .{});
        return error.WrongArgs;
    }
    var l = try std.fmt.parseInt(u32, args[1], 10);
    var r = try std.fmt.parseInt(u32, args[2], 10);
    // A good reading is https://renato.athaydes.com/posts/testing-building-c-with-zig.html
    std.debug.print("PGCD({d},{d}) = {d}\n", .{ l, r, c.pgcd(l, r) });
}

const expect = @import("std").testing.expect;

fn expectidentical(i: u32) !void {
    try expect(c.pgcd(i, i) == i);
}

test "identical" {
    try expectidentical(1);
    try expectidentical(7);
    try expectidentical(18);
}

test "primes" {
    try expect(c.pgcd(4, 13) == 1);
}

test "pgcdexists" {
    try expect(c.pgcd(15, 35) == 5);
}

test "pgcdlower" {
    try expect(c.pgcd(15, 5) == 5);
}