const std = @import("std");
const stub = @import("frontend/stub.zig");
const IO = @import("frontend/io_interface.zig").IOInterface;
const Action = @import("actions.zig").Action;

pub fn run(allocator: std.mem.Allocator, io: *IO) !void {
    try io.displayMessage("Initialized");

    var action = Action.illegal;
    var tick_count: usize = 0;
    while (action != Action.exit) {
        const str = try std.fmt.allocPrint(allocator, "{}", .{tick_count});
        defer allocator.free(str);
        try io.displayMessage(str);

        action = try io.waitForTick();
        switch (action) {
            Action.tick => {
                tick_count += 1;
            },
            else => {},
        }
    }
}

test "can run game" {
    const allocator = std.testing.allocator;

    var as = stub.ActionStack.init(allocator);
    defer as.deinit();

    var io = try stub.IO.init(allocator, as);
    defer io.deinit();

    var res: ?anyerror = null;
    run(allocator, &io) catch |err| {
        res = err;
    };
    try std.testing.expect(res != null);
    try std.testing.expectEqual(error.NoAvailableAction, res.?);
}

test "game exits on Action.exit" {
    const allocator = std.testing.allocator;

    var as = stub.ActionStack.init(allocator);
    defer as.deinit();
    try as.scheduleAction(Action.exit);

    var io = try stub.IO.init(allocator, as);
    defer io.deinit();

    try run(allocator, &io);
    const io_obj: *const stub.IO = @ptrCast(@alignCast(io.ptr));
    var actions = io_obj.out_as;

    const act = actions.next().?;
    try std.testing.expectEqual(Action.exit, act);
}

test "game processes stream of actions" {
    const allocator = std.testing.allocator;

    var as = stub.ActionStack.init(allocator);
    defer as.deinit();

    try as.scheduleAction(Action.exit);
    try as.scheduleAction(Action.move_right);
    try as.scheduleAction(Action.move_left);
    try as.scheduleAction(Action.move_down);
    try as.scheduleAction(Action.move_up);
    try as.scheduleAction(Action.tick);

    var io = try stub.IO.init(allocator, as);
    defer io.deinit();

    try run(allocator, &io);
    const io_obj: *const stub.IO = @ptrCast(@alignCast(io.ptr));
    var actions = io_obj.out_as;

    var act = actions.next().?;
    try std.testing.expectEqual(Action.exit, act);
    act = actions.next().?;
    try std.testing.expectEqual(Action.move_right, act);
    act = actions.next().?;
    try std.testing.expectEqual(Action.move_left, act);
    act = actions.next().?;
    try std.testing.expectEqual(Action.move_down, act);
    act = actions.next().?;
    try std.testing.expectEqual(Action.move_up, act);
    act = actions.next().?;
    try std.testing.expectEqual(Action.tick, act);
}