import { describe, expect, it, vi } from 'vitest';
import { BridgeEventBus } from '../src/event-bus';
import type { FriendMessage, GroupMessage } from '../src/events';

function makeFriendMessage(): FriendMessage {
    return {
        kind: 'friend_message',
        time: 1700000000,
        selfUin: 10001,
        senderUin: 22222,
        senderNick: 'peer',
        msgSeq: 1,
        msgId: 1,
        elements: [{ type: 'text', text: 'hi' }],
    };
}

function makeGroupMessage(): GroupMessage {
    return {
        kind: 'group_message',
        groupName: '',
        time: 1700000000,
        selfUin: 10001,
        groupId: 99999,
        senderUin: 22222,
        senderNick: 'peer',
        senderCard: '',
        senderRole: 'member',
        msgSeq: 2,
        msgId: 2,
        elements: [{ type: 'text', text: 'hi' }],
    };
}

describe('BridgeEventBus', () => {
    it('keeps the current kind and wildcard subscribers stable while dispatching', async () => {
        const bus = new BridgeEventBus();
        const peer = vi.fn();
        const tap = vi.fn();
        const later = vi.fn();
        const laterTap = vi.fn();
        bus.on('friend_message', () => {
            offPeer();
            offTap();
            bus.on('friend_message', later);
            bus.onAny(laterTap);
        });
        const offPeer = bus.on('friend_message', peer);
        const offTap = bus.onAny(tap);

        await bus.emit(makeFriendMessage());
        expect(peer).toHaveBeenCalledOnce();
        expect(tap).toHaveBeenCalledOnce();
        expect(later).not.toHaveBeenCalled();
        expect(laterTap).not.toHaveBeenCalled();

        await bus.emit(makeFriendMessage());
        expect(peer).toHaveBeenCalledOnce();
        expect(tap).toHaveBeenCalledOnce();
        expect(later).toHaveBeenCalledOnce();
        expect(laterTap).toHaveBeenCalledOnce();
    });

    it('finishes the current dispatch when a handler clears subscriptions', async () => {
        const bus = new BridgeEventBus();
        const peer = vi.fn();
        const tap = vi.fn();
        bus.on('friend_message', () => bus.clear());
        bus.on('friend_message', peer);
        bus.onAny(tap);
        await bus.emit(makeFriendMessage());
        await bus.emit(makeFriendMessage());
        expect(peer).toHaveBeenCalledOnce();
        expect(tap).toHaveBeenCalledOnce();
    });

    it.each(['kind', 'any'] as const)('owns each %s subscription independently', async (type) => {
        const bus = new BridgeEventBus();
        const handler = vi.fn();
        const subscribe = () =>
            type === 'kind' ? bus.on('friend_message', handler) : bus.onAny(handler);
        const off = subscribe();
        subscribe();
        off();
        off();
        await bus.emit(makeFriendMessage());
        expect(handler).toHaveBeenCalledOnce();

        bus.clear();
        subscribe();
        off();
        await bus.emit(makeFriendMessage());
        expect(handler).toHaveBeenCalledTimes(2);
    });

    it('off removes every registration of the named handler', async () => {
        const bus = new BridgeEventBus();
        const handler = vi.fn();
        bus.on('friend_message', handler);
        bus.on('friend_message', handler);
        bus.off('friend_message', handler);
        expect(bus.has('friend_message')).toBe(false);
        await bus.emit(makeFriendMessage());
        expect(handler).not.toHaveBeenCalled();
    });

    it('routes events only to subscribers of the matching kind', async () => {
        const bus = new BridgeEventBus();
        const friend = vi.fn();
        const group = vi.fn();
        bus.on('friend_message', friend);
        bus.on('group_message', group);

        await bus.emit(makeFriendMessage());
        await bus.emit(makeGroupMessage());

        expect(friend).toHaveBeenCalledTimes(1);
        expect(group).toHaveBeenCalledTimes(1);
    });

    it('runs every subscriber in parallel for one kind', async () => {
        const bus = new BridgeEventBus();
        const order: string[] = [];
        bus.on('friend_message', async () => {
            await new Promise((r) => setTimeout(r, 20));
            order.push('slow');
        });
        bus.on('friend_message', () => {
            order.push('fast');
        });

        await bus.emit(makeFriendMessage());
        // The synchronous handler must finish before the async one — proves we
        // don't serialize handlers across the kind.
        expect(order).toEqual(['fast', 'slow']);
    });

    it('isolates handler errors and reports them via onError', async () => {
        const seen: Array<{ kind: string; err: unknown }> = [];
        const bus = new BridgeEventBus({ onError: (kind, err) => seen.push({ kind, err }) });
        const ok = vi.fn();
        bus.on('friend_message', () => {
            throw new Error('boom');
        });
        bus.on('friend_message', ok);

        await bus.emit(makeFriendMessage());

        expect(ok).toHaveBeenCalledTimes(1);
        expect(seen).toHaveLength(1);
        expect(seen[0].kind).toBe('friend_message');
        expect((seen[0].err as Error).message).toBe('boom');
    });

    it('supports unsubscribe via the returned disposer', async () => {
        const bus = new BridgeEventBus();
        const handler = vi.fn();
        const off = bus.on('friend_message', handler);

        await bus.emit(makeFriendMessage());
        expect(handler).toHaveBeenCalledTimes(1);

        off();
        await bus.emit(makeFriendMessage());
        expect(handler).toHaveBeenCalledTimes(1);
    });

    it('supports onAny and isolates its errors separately', async () => {
        const seen: Array<{ kind: string; err: unknown }> = [];
        const bus = new BridgeEventBus({ onError: (kind, err) => seen.push({ kind, err }) });
        const tap = vi.fn();
        bus.onAny(tap);
        bus.onAny(() => {
            throw new Error('any-fail');
        });

        await bus.emit(makeFriendMessage());
        await bus.emit(makeGroupMessage());

        expect(tap).toHaveBeenCalledTimes(2);
        expect(seen).toHaveLength(2);
        expect(seen.every((s) => s.kind === '*')).toBe(true);
    });

    it('reports has() based on per-kind + onAny subscriptions', () => {
        const bus = new BridgeEventBus();
        expect(bus.has('friend_message')).toBe(false);

        const off = bus.on('friend_message', () => {});
        expect(bus.has('friend_message')).toBe(true);
        off();
        expect(bus.has('friend_message')).toBe(false);

        bus.onAny(() => {});
        expect(bus.has('friend_message')).toBe(true);
    });

    it('clear() drops every subscriber', async () => {
        const bus = new BridgeEventBus();
        const handler = vi.fn();
        bus.on('friend_message', handler);
        bus.onAny(handler);

        bus.clear();
        await bus.emit(makeFriendMessage());

        expect(handler).not.toHaveBeenCalled();
    });
});