package rpc

import (
	"context"
	"testing"

	"github.com/iamxvbaba/td/clock"
	"github.com/iamxvbaba/td/tg"
	"go.uber.org/zap/zaptest"

	appchannels "telesrv/internal/app/channels"
	appusers "telesrv/internal/app/users"
	"telesrv/internal/domain"
	"telesrv/internal/store/memory"
)

// A reply inside a forum must inherit the *target's* topic, never the target's
// own message id. Regression: replying to a General message produced
// reply_to_top_id = <that message's id>, a topic that no client can resolve, so
// the reply vanished from every topic view and reply-jump said "doesn't exist".
func TestForumReplyInheritsTargetTopic(t *testing.T) {
	ctx := context.Background()
	userStore := memory.NewUserStore()
	owner, _ := userStore.Create(ctx, domain.User{AccessHash: 91, Phone: "15550009101", FirstName: "Owner"})
	channelStore := memory.NewChannelStore()
	r := New(Config{}, Deps{
		Users:    appusers.NewService(userStore),
		Channels: appchannels.NewService(channelStore),
	}, zaptest.NewLogger(t), clock.System)
	ownerCtx := WithUserID(ctx, owner.ID)

	created, err := r.onChannelsCreateChannel(ownerCtx, &tg.ChannelsCreateChannelRequest{Title: "Forum", Megagroup: true})
	if err != nil {
		t.Fatalf("create channel: %v", err)
	}
	channel := created.(*tg.Updates).Chats[0].(*tg.Channel)
	input := &tg.InputChannel{ChannelID: channel.ID, AccessHash: channel.AccessHash}
	peer := &tg.InputPeerChannel{ChannelID: channel.ID, AccessHash: channel.AccessHash}
	if _, err := r.onChannelsToggleForum(ownerCtx, &tg.ChannelsToggleForumRequest{Channel: input, Enabled: true, Tabs: true}); err != nil {
		t.Fatalf("toggle forum: %v", err)
	}
	topicUpd, err := r.onMessagesCreateForumTopic(ownerCtx, &tg.MessagesCreateForumTopicRequest{
		Peer: peer, Title: "Test", IconColor: domain.DefaultForumTopicIconColor, RandomID: 9101001,
	})
	if err != nil {
		t.Fatalf("create topic: %v", err)
	}
	testTopicID := forumTopicRootMessageID(t, topicUpd, "Test")

	send := func(text string, randomID int64, reply *tg.InputReplyToMessage) *tg.Message {
		req := &tg.MessagesSendMessageRequest{Peer: peer, Message: text, RandomID: randomID}
		if reply != nil {
			req.SetReplyTo(reply)
		}
		upd, err := r.onMessagesSendMessage(ownerCtx, req)
		if err != nil {
			t.Fatalf("send %q: %v", text, err)
		}
		for _, u := range upd.(*tg.Updates).Updates {
			if nm, ok := u.(*tg.UpdateNewChannelMessage); ok {
				if m, ok := nm.Message.(*tg.Message); ok && m.Message == text {
					return m
				}
			}
		}
		t.Fatalf("no new message for %q in %+v", text, upd)
		return nil
	}
	topID := func(m *tg.Message) int {
		h, ok := m.ReplyTo.(*tg.MessageReplyHeader)
		if !ok {
			t.Fatalf("message %d has reply header %T, want *MessageReplyHeader", m.ID, m.ReplyTo)
		}
		id, _ := h.GetReplyToTopID()
		if !h.ForumTopic {
			t.Fatalf("message %d reply header missing forum_topic flag: %+v", m.ID, h)
		}
		return id
	}

	// A plain General message (no reply header).
	g1 := send("g1", 9101002, nil)

	// Reply to it -> topic must be General (1), not g1.ID.
	r1 := send("r1", 9101003, &tg.InputReplyToMessage{ReplyToMsgID: g1.ID})
	if got := topID(r1); got != domain.ForumGeneralTopicID {
		t.Fatalf("reply to a General message: reply_to_top_id = %d, want %d (General), not the target id %d",
			got, domain.ForumGeneralTopicID, g1.ID)
	}

	// Reply again, this time the client also passes top_msg_id: 1 (General).
	// Previously this was rejected because General has no channel_forum_topics row.
	replyWithTop := &tg.InputReplyToMessage{ReplyToMsgID: g1.ID}
	replyWithTop.SetTopMsgID(domain.ForumGeneralTopicID)
	r2 := send("r2", 9101004, replyWithTop)
	if got := topID(r2); got != domain.ForumGeneralTopicID {
		t.Fatalf("reply with top_msg_id=1: reply_to_top_id = %d, want %d", got, domain.ForumGeneralTopicID)
	}

	// Post directly into the "Test" topic, then reply to a plain message there.
	tInTopic := &tg.InputReplyToMessage{ReplyToMsgID: 0}
	tInTopic.SetTopMsgID(testTopicID)
	m1 := send("t1", 9101005, tInTopic)
	if got := topID(m1); got != testTopicID {
		t.Fatalf("message in Test topic: reply_to_top_id = %d, want %d", got, testTopicID)
	}
	rt := send("rt", 9101006, &tg.InputReplyToMessage{ReplyToMsgID: m1.ID})
	if got := topID(rt); got != testTopicID {
		t.Fatalf("reply inside Test topic: reply_to_top_id = %d, want %d (topic), not %d", got, testTopicID, m1.ID)
	}

	// Replying to a General message while claiming a mismatched topic is rejected.
	bad := &tg.InputReplyToMessage{ReplyToMsgID: g1.ID}
	bad.SetTopMsgID(testTopicID)
	req := &tg.MessagesSendMessageRequest{Peer: peer, Message: "bad", RandomID: 9101007}
	req.SetReplyTo(bad)
	if _, err := r.onMessagesSendMessage(ownerCtx, req); err == nil {
		t.Fatal("reply with a topic id that doesn't match the target's topic was accepted")
	}
}