const c = @cImport({
    @cInclude("zaprus.h");
});

fn zigToCMessage(msg: zaprus.Message) !c.SaprusMessage {
    return switch (msg) {
        .relay => |r| .{
            .packet_type = @intFromEnum(msg),
            .payload_len = @intCast(r.payload.len),
            .headers = .{ .relay = .{
                .dest = r.header.dest,
            } },
            .payload = @constCast(r.payload.ptr),
        },
        .connection => |con| .{
            .packet_type = @intFromEnum(msg),
            .payload_len = @intCast(con.payload.len),
            .headers = .{ .connection = .{
                .src_port = con.header.src_port,
                .dest_port = con.header.dest_port,
                .seq_num = con.header.seq_num,
                .msg_id = con.header.msg_id,
                ._reserved = con.header.reserved,
                .options = @bitCast(con.header.options),
            } },
            .payload = @constCast(con.payload.ptr),
        },
        .file_transfer => return zaprus.Error.NotImplementedSaprusType,
        else => return zaprus.Error.UnknownSaprusType,
    };
}

fn cToZigMessage(msg: c.SaprusMessage) !zaprus.Message {
    const msg_type: zaprus.PacketType = @enumFromInt(msg.packet_type);
    return switch (msg_type) {
        .relay => .{
            .relay = .{
                .header = .{
                    .dest = msg.headers.relay.dest[0..4].*,
                },
                .payload = msg.payload[0..msg.payload_len],
            },
        },
        .connection => .{
            .connection = .{
                .header = .{
                    .src_port = msg.headers.connection.src_port,
                    .dest_port = msg.headers.connection.dest_port,
                    .seq_num = msg.headers.connection.seq_num,
                    .msg_id = msg.headers.connection.msg_id,
                    .reserved = msg.headers.connection._reserved,
                    .options = @bitCast(msg.headers.connection.options),
                },
                .payload = msg.payload[0..msg.payload_len],
            },
        },
        .file_transfer => return zaprus.Error.NotImplementedSaprusType,
        else => return zaprus.Error.UnknownSaprusType,
    };
}

// client
export fn zaprus_init() c_int {
    SaprusClient.init() catch return 1;
    return 0;
}

export fn zaprus_deinit() c_int {
    SaprusClient.deinit();
    return 0;
}

export fn zaprus_send_relay(payload: [*]const u8, len: usize, dest: [*]u8) c_int {
    SaprusClient.sendRelay(payload[0..len], dest[0..4].*, allocator) catch return 1;
    return 0;
}

export fn zaprus_send_initial_connection(payload: [*]const u8, len: usize, initial_port: u16) c_int {
    _ = SaprusClient.sendInitialConnection(payload[0..len], initial_port, allocator) catch return 1;
    return 0;
}

export fn zaprus_connect(payload: [*]const u8, len: usize) ?*c.SaprusMessage {
    if (SaprusClient.connect(payload[0..len], allocator)) |msg| {
        var m = zigToCMessage(msg) catch return null;
        return &m;
    } else |_| {
        return null;
    }
}

// message

/// ptr should be freed by the caller.
export fn zaprus_message_to_bytes(msg: c.SaprusMessage, ptr: *[*]u8, len: *usize) c_int {
    var m = cToZigMessage(msg) catch return 1;
    const bytes = m.toBytes(allocator) catch return 1;
    ptr.* = bytes.ptr;
    len.* = bytes.len;
    return 0;
}

/// Return value should be destroyed with zaprus_message_deinit.
export fn zaprus_message_from_bytes(bytes: [*]const u8, len: usize) ?*c.SaprusMessage {
    if (zaprus.Message.fromBytes(bytes[0..len], allocator)) |msg| {
        var m = zigToCMessage(msg) catch return null;
        return &m;
    } else |_| return null;
}

export fn zaprus_message_deinit(msg: *c.SaprusMessage) void {
    if (cToZigMessage(msg.*)) |m| {
        m.deinit(allocator);
    } else |_| unreachable;
}

const std = @import("std");

const zaprus = @import("./root.zig");
const SaprusClient = zaprus.Client;

const allocator = std.heap.c_allocator;

test {
    std.testing.refAllDeclsRecursively(@This());
}