const std = @import("std");
const thespian = @import("thespian");
const cbor = @import("cbor");
const framing = @import("framing");
const protocol = @import("protocol");
const endpoint = @import("endpoint");
const build_options = @import("build_options");

const Allocator = std.mem.Allocator;
const result = thespian.result;
const unexpected = thespian.unexpected;
const pid_ref = thespian.pid_ref;
const Receiver = thespian.Receiver;
const message = thespian.message;
const extract = thespian.extract;

/// Top-level test actor. Registers as "test_receiver", spawns the endpoint,
/// sends ["hello"] to the child's echo actor, and verifies the reply.
const TestActor = struct {
    allocator: Allocator,
    ep: thespian.pid,
    receiver: Receiver(*@This()),

    const Args = struct { allocator: Allocator };

    fn start(args: Args) result {
        return init(args) catch |e| return thespian.exit_error(e, @errorReturnTrace());
    }

    fn init(args: Args) !void {
        // Register self so the endpoint can deliver the echo reply here.
        thespian.env.get().proc_set("test_receiver", thespian.self_pid().ref());

        const argv = try args.allocator.dupe(u8, message.fmt(.{build_options.remote_child_endpoint_path}).buf);
        const ep = try thespian.spawn_link(
            args.allocator,
            endpoint.Args{
                .allocator = args.allocator,
                .argv = argv,
            },
            endpoint.start,
            "endpoint",
        );

        // Send ["hello"] to the child's "echo" actor through the endpoint.
        try ep.send(.{ "send", @as(u64, 1), "echo", .{"hello"} });

        const self = try args.allocator.create(@This());
        self.* = .{
            .allocator = args.allocator,
            .ep = ep,
            .receiver = .init(receive_fn, deinit, self),
        };
        errdefer self.deinit();
        thespian.receive(&self.receiver);
    }

    fn deinit(self: *@This()) void {
        self.ep.deinit();
        self.allocator.destroy(self);
    }

    fn receive_fn(self: *@This(), from: pid_ref, m: message) result {
        return self.receive(from, m) catch |e| return thespian.exit_error(e, @errorReturnTrace());
    }

    fn receive(_: *@This(), _: pid_ref, m: message) !void {
        // The endpoint delivers the echo reply as the raw payload: ["hello"]
        if (try m.match(.{"hello"})) {
            return thespian.exit("success");
        } else {
            return unexpected(m);
        }
    }
};

test "remote: endpoint delivers message cross-process and receives reply" {
    const allocator = std.testing.allocator;
    var ctx = try thespian.context.init(allocator);
    defer ctx.deinit();

    var success = false;
    var exit_handler = thespian.make_exit_handler(&success, struct {
        fn handle(ok: *bool, status: []const u8) void {
            ok.* = std.mem.eql(u8, status, "success");
        }
    }.handle);

    _ = try ctx.spawn_link(
        TestActor.Args{ .allocator = allocator },
        TestActor.start,
        "test_actor",
        &exit_handler,
        null,
    );

    ctx.run();

    if (!success) return error.TestFailed;
}