const std = @import("std");

const zigeru = @import("zigeru");
const Bot = zigeru.bot.Bot;
const Error = zigeru.bot.Error;
const UserCommand = zigeru.commands.UserCommand;
const AdminCommand = zigeru.commands.AdminCommand;
const BotMessage = zigeru.bot.Message;
const BotResponse = zigeru.bot.Response;
const zircon = @import("zircon");

var debug_allocator = std.heap.DebugAllocator(.{}).init;

pub fn main() !void {
    const allocator = debug_allocator.allocator();
    defer _ = debug_allocator.deinit();

    var channels: [0][]const u8 = .{};

    // Create a zircon.Client with a given configuration.
    var client = try zircon.Client.init(allocator, .{
        .user = "eru",
        .nick = "eru",
        .real_name = "Eru (zigeru) bot",
        .server = "irc.dtek.se",
        .port = 6697,
        .tls = true,
        .channels = &channels,
    });
    defer client.deinit();

    var bot_adapter = try BotAdapter.init(allocator);
    defer bot_adapter.deinit();
    client.register_message_closure(bot_adapter.closure());
    // Connect to the IRC server and perform registration.
    try client.connect();
    try client.register();
    try client.join("#eru-tests");
    try client.join("#eru-admin");

    client.loop(.{}) catch |err| {
        std.debug.print("eru exited with error: {}\n", .{err});
        return;
    };
}

pub const Adapter = struct {
    ptr: *anyopaque,
    callbackFn: *const fn (*anyopaque, zircon.Message) ?zircon.Message,
};

pub const BotAdapter = struct {
    bot: Bot,
    allocator: std.mem.Allocator,

    pub fn init(allocator: std.mem.Allocator) !BotAdapter {
        return BotAdapter{
            .bot = try Bot.init(allocator),
            .allocator = allocator,
        };
    }

    pub fn deinit(self: *BotAdapter) void {
        self.bot.deinit();
    }

    pub fn callback(self: *BotAdapter, message: zircon.Message) ?zircon.Message {
        switch (message) {
            .PRIVMSG => |msg| {
                std.log.debug(
                    "received message: nick {?s}, user: {?s}, host: {?s}, targets: {s}, text: {s}",
                    .{ msg.prefix.?.nick, msg.prefix.?.user, msg.prefix.?.host, msg.targets, msg.text },
                );
                const nick = if (msg.prefix) |prefix| if (prefix.nick) |nick| nick else "unknown" else "unknown";
                if (UserCommand.parse(nick, msg.text)) |cmd| {
                    return toIRC(self.bot.execute(&cmd, msg.targets) catch |err| return report_error(err));
                }
                if (AdminCommand.parse(msg.text)) |cmd| {
                    return toIRC(self.bot.execute_admin(&cmd, "#eru-admin") catch |err| return report_error(err));
                }
                const bot_msg = BotMessage.init_owned(
                    self.allocator,
                    std.time.timestamp(),
                    nick,
                    msg.targets,
                    msg.text,
                ) catch |err| return report_error(err);
                self.bot.store(bot_msg);
                return null;
            },
            .JOIN => |msg| {
                std.log.debug("received join message: channels {s}", .{msg.channels});
                return null;
            },
            else => {
                std.log.debug("received unknown message {}", .{message});
                return null;
            },
        }
    }

    fn report_error(err: Error) zircon.Message {
        const err_msg = switch (err) {
            Error.NoMessage => "no matching message",
            Error.OutOfMemory => "out of memory",
            Error.WriteFailed => "write failed",
        };
        return .{ .PRIVMSG = .{ .prefix = null, .targets = "#eru-admin", .text = err_msg } };
    }

    pub fn erased_callback(self: *anyopaque, message: zircon.Message) ?zircon.Message {
        const a: *@This() = @ptrCast(@alignCast(self));
        return a.callback(message);
    }

    pub fn closure(self: *BotAdapter) zircon.MessageClosure {
        return .{
            .ptr = self,
            .callbackFn = BotAdapter.erased_callback,
        };
    }
};

/// toIRC converts a bot response and converts it to a IRC message.
fn toIRC(response: BotResponse) zircon.Message {
    switch (response) {
        .join => |join| return .{
            .JOIN = .{ .prefix = null, .channels = join.channels },
        },
        .privmsg => |msg| return .{
            .PRIVMSG = .{ .prefix = null, .targets = msg.targets, .text = msg.text },
        },
    }
}

test "substitute" {
    var bot_adapter = try BotAdapter.init(std.testing.allocator);
    defer bot_adapter.deinit();
    const prefix = zircon.Prefix{ .nick = "jassob", .user = "jassob", .host = "localhost" };
    const msg = zircon.Message{
        .PRIVMSG = .{
            .prefix = prefix,
            .targets = "#test",
            .text = "hello world",
        },
    };
    if (bot_adapter.callback(msg)) |_| {
        @panic("unexpected response");
    }
    const cmd_msg = zircon.Message{
        .PRIVMSG = .{
            .prefix = prefix,
            .targets = "#test",
            .text = "s/world/zig/",
        },
    };
    const response = bot_adapter.callback(cmd_msg);
    try std.testing.expect(response != null);
    try std.testing.expectEqualStrings("jassob: \"hello zig\"", response.?.PRIVMSG.text);
}

test "get empty backlog message" {
    var bot_adapter = try BotAdapter.init(std.testing.allocator);
    defer bot_adapter.deinit();
    const prefix = zircon.Prefix{ .nick = "jassob", .user = "jassob", .host = "localhost" };
    const msg = zircon.Message{
        .PRIVMSG = .{ .prefix = prefix, .targets = "#eru-admin", .text = "!backlog 0" },
    };
    try std.testing.expectEqualDeep("no matching message", bot_adapter.callback(msg).?.PRIVMSG.text);
}