/**
 * QQ Bot WebSocket Monitor
 *
 * Handles WebSocket connection to QQ Bot Gateway for receiving events.
 */

import WebSocket from "ws";
import type { MoltbotConfig, MarkdownTableMode } from "clawdbot/plugin-sdk";

import type { ResolvedQQAccount } from "./accounts.js";
import {
    getAccessToken,
    getGatewayUrl,
    sendC2CMessage,
    sendGroupMessage,
} from "./api.js";
import { getQQRuntime } from "./runtime.js";
import { chunkQQText } from "./send.js";
import {
    OpCode,
    EventType,
    DEFAULT_INTENTS,
    type GatewayPayload,
    type HelloData,
    type ReadyData,
    type QQMessageEvent,
    type IdentifyData,
    type ResumeData,
} from "./types.js";

export interface QQMonitorOptions {
    account: ResolvedQQAccount;
    config: MoltbotConfig;
    abortSignal: AbortSignal;
    statusSink?: (patch: {
        lastInboundAt?: number;
        lastOutboundAt?: number;
        sessionId?: string;
    }) => void;
    log?: {
        info: (msg: string) => void;
        error: (msg: string) => void;
    };
}

export interface QQMonitorResult {
    stop: () => void;
}

const QQ_TEXT_LIMIT = 2000;
const DEFAULT_MEDIA_MAX_MB = 5;

type QQCoreRuntime = ReturnType<typeof getQQRuntime>;

/**
 * Start QQ Bot WebSocket monitor
 */
export async function monitorQQProvider(
    options: QQMonitorOptions,
): Promise<QQMonitorResult> {
    const { account, config, abortSignal, statusSink, log } = options;

    if (!account.appId || !account.appSecret) {
        throw new Error("QQ appId and appSecret are required");
    }

    const core = getQQRuntime();
    let stopped = false;
    let ws: WebSocket | null = null;
    let heartbeatInterval: ReturnType<typeof setInterval> | null = null;
    let sessionId: string | null = null;
    let lastSeq: number | null = null;
    let reconnectAttempts = 0;
    const maxReconnectAttempts = 10;

    const stop = () => {
        stopped = true;
        if (heartbeatInterval) {
            clearInterval(heartbeatInterval);
            heartbeatInterval = null;
        }
        if (ws) {
            ws.close();
            ws = null;
        }
    };

    abortSignal.addEventListener("abort", stop, { once: true });

    const connect = async () => {
        if (stopped || abortSignal.aborted) return;

        try {
            const token = await getAccessToken(account.appId!, account.appSecret!);
            const gatewayUrl = await getGatewayUrl(token);

            log?.info(`[${account.accountId}] Connecting to gateway: ${gatewayUrl}`);

            ws = new WebSocket(gatewayUrl);

            ws.on("open", () => {
                log?.info(`[${account.accountId}] WebSocket connected`);
                reconnectAttempts = 0;
            });

            ws.on("message", async (data) => {
                try {
                    const payload = JSON.parse(data.toString()) as GatewayPayload;
                    await handlePayload(payload, token);
                } catch (err) {
                    log?.error(
                        `[${account.accountId}] Failed to parse message: ${String(err)}`,
                    );
                }
            });

            ws.on("close", (code, reason) => {
                log?.info(
                    `[${account.accountId}] WebSocket closed: ${code} ${reason.toString()}`,
                );
                if (heartbeatInterval) {
                    clearInterval(heartbeatInterval);
                    heartbeatInterval = null;
                }
                scheduleReconnect();
            });

            ws.on("error", (err) => {
                log?.error(`[${account.accountId}] WebSocket error: ${String(err)}`);
            });
        } catch (err) {
            log?.error(`[${account.accountId}] Failed to connect: ${String(err)}`);
            scheduleReconnect();
        }
    };

    const scheduleReconnect = () => {
        if (stopped || abortSignal.aborted) return;
        if (reconnectAttempts >= maxReconnectAttempts) {
            log?.error(`[${account.accountId}] Max reconnect attempts reached`);
            return;
        }

        reconnectAttempts++;
        const delay = Math.min(1000 * Math.pow(2, reconnectAttempts), 30000);
        log?.info(
            `[${account.accountId}] Reconnecting in ${delay}ms (attempt ${reconnectAttempts})`,
        );
        setTimeout(connect, delay);
    };

    const handlePayload = async (
        payload: GatewayPayload,
        token: string,
    ): Promise<void> => {
        // Update sequence number
        if (payload.s !== undefined) {
            lastSeq = payload.s;
        }

        switch (payload.op) {
            case OpCode.Hello: {
                const hello = payload.d as HelloData;
                log?.info(
                    `[${account.accountId}] Received Hello, heartbeat interval: ${hello.heartbeat_interval}ms`,
                );

                // Start heartbeat
                if (heartbeatInterval) clearInterval(heartbeatInterval);
                heartbeatInterval = setInterval(() => {
                    sendHeartbeat();
                }, hello.heartbeat_interval);

                // Send Identify or Resume
                if (sessionId && lastSeq !== null) {
                    sendResume(token);
                } else {
                    sendIdentify(token);
                }
                break;
            }

            case OpCode.HeartbeatAck:
                // Heartbeat acknowledged
                break;

            case OpCode.Dispatch:
                statusSink?.({ lastInboundAt: Date.now() });
                await handleEvent(payload.t!, payload.d, token);
                break;

            case OpCode.Reconnect:
                log?.info(`[${account.accountId}] Received Reconnect, reconnecting...`);
                ws?.close();
                break;

            case OpCode.InvalidSession: {
                const resumable = payload.d as boolean;
                log?.info(
                    `[${account.accountId}] Invalid session, resumable: ${resumable}`,
                );
                if (!resumable) {
                    sessionId = null;
                    lastSeq = null;
                }
                // Wait a bit before reconnecting
                setTimeout(() => {
                    if (resumable && sessionId) {
                        sendResume(token);
                    } else {
                        sendIdentify(token);
                    }
                }, 1000 + Math.random() * 4000);
                break;
            }
        }
    };

    const sendHeartbeat = () => {
        if (!ws || ws.readyState !== WebSocket.OPEN) return;

        const payload: GatewayPayload<number | null> = {
            op: OpCode.Heartbeat,
            d: lastSeq,
        };

        ws.send(JSON.stringify(payload));
    };

    const sendIdentify = async (token: string) => {
        if (!ws || ws.readyState !== WebSocket.OPEN) return;

        const intents = account.config.intents ?? DEFAULT_INTENTS;

        const payload: GatewayPayload<IdentifyData> = {
            op: OpCode.Identify,
            d: {
                token: `QQBot ${token}`,
                intents,
                properties: {
                    $os: "linux",
                    $browser: "moltbot",
                    $device: "moltbot",
                },
            },
        };

        log?.info(`[${account.accountId}] Sending Identify with intents: ${intents}`);
        ws.send(JSON.stringify(payload));
    };

    const sendResume = (token: string) => {
        if (!ws || ws.readyState !== WebSocket.OPEN || !sessionId) return;

        const payload: GatewayPayload<ResumeData> = {
            op: OpCode.Resume,
            d: {
                token: `QQBot ${token}`,
                session_id: sessionId,
                seq: lastSeq ?? 0,
            },
        };

        log?.info(`[${account.accountId}] Sending Resume for session: ${sessionId}`);
        ws.send(JSON.stringify(payload));
    };

    const handleEvent = async (
        eventType: string,
        data: unknown,
        token: string,
    ): Promise<void> => {
        switch (eventType) {
            case EventType.READY: {
                const ready = data as ReadyData;
                sessionId = ready.session_id;
                statusSink?.({ sessionId });
                log?.info(
                    `[${account.accountId}] Ready! Bot: ${ready.user.username} (${ready.user.id})`,
                );
                break;
            }

            case EventType.RESUMED:
                log?.info(`[${account.accountId}] Session resumed`);
                break;

            case EventType.C2C_MESSAGE_CREATE:
                await handleC2CMessage(data as QQMessageEvent, token);
                break;

            case EventType.GROUP_AT_MESSAGE_CREATE:
                await handleGroupMessage(data as QQMessageEvent, token);
                break;

            case EventType.DIRECT_MESSAGE_CREATE:
            case EventType.AT_MESSAGE_CREATE:
            case EventType.MESSAGE_CREATE:
                // TODO: Implement channel message handling
                log?.info(`[${account.accountId}] Received channel event: ${eventType}`);
                break;

            default:
                log?.info(`[${account.accountId}] Unhandled event: ${eventType}`);
        }
    };

    const handleC2CMessage = async (
        message: QQMessageEvent,
        token: string,
    ): Promise<void> => {
        const senderId = message.author.user_openid;
        if (!senderId) return;

        log?.info(
            `[${account.accountId}] C2C message from ${senderId}: ${message.content?.slice(0, 50)}`,
        );

        await processMessageWithPipeline({
            message,
            token,
            chatType: "c2c",
            chatId: senderId,
            senderId,
            isGroup: false,
        });
    };

    const handleGroupMessage = async (
        message: QQMessageEvent,
        token: string,
    ): Promise<void> => {
        const groupId = message.group_openid;
        const senderId = message.author.member_openid;
        if (!groupId || !senderId) return;

        log?.info(
            `[${account.accountId}] Group message in ${groupId} from ${senderId}: ${message.content?.slice(0, 50)}`,
        );

        await processMessageWithPipeline({
            message,
            token,
            chatType: "group",
            chatId: groupId,
            senderId,
            isGroup: true,
        });
    };

    const processMessageWithPipeline = async (params: {
        message: QQMessageEvent;
        token: string;
        chatType: "c2c" | "group";
        chatId: string;
        senderId: string;
        isGroup: boolean;
    }): Promise<void> => {
        const { message, token, chatType, chatId, senderId, isGroup } = params;

        const rawBody = message.content?.trim() || "";
        if (!rawBody) return;

        const dmPolicy = account.config.dmPolicy ?? "open";
        const configAllowFrom = (account.config.allowFrom ?? []).map((v) =>
            String(v),
        );

        // Check authorization for DMs
        if (!isGroup && dmPolicy !== "open") {
            const allowed =
                configAllowFrom.includes("*") ||
                configAllowFrom.some(
                    (entry) => entry.toLowerCase() === senderId.toLowerCase(),
                );

            if (!allowed) {
                if (dmPolicy === "pairing") {
                    const { code, created } = await core.channel.pairing.upsertPairingRequest({
                        channel: "qq",
                        id: senderId,
                        meta: {},
                    });

                    if (created) {
                        log?.info(`[${account.accountId}] Pairing request from ${senderId}`);
                        const replyText = core.channel.pairing.buildPairingReply({
                            channel: "qq",
                            idLine: `Your QQ OpenID: ${senderId}`,
                            code,
                        });

                        await sendC2CMessage(token, senderId, {
                            content: replyText,
                            msg_type: 0,
                            msg_id: message.id,
                        });
                        statusSink?.({ lastOutboundAt: Date.now() });
                    }
                }
                return;
            }
        }

        // Resolve agent route
        const route = core.channel.routing.resolveAgentRoute({
            cfg: config,
            channel: "qq",
            accountId: account.accountId,
            peer: {
                kind: isGroup ? "group" : "dm",
                id: chatId,
            },
        });

        const fromLabel = isGroup ? `group:${chatId}` : `user:${senderId}`;
        const storePath = core.channel.session.resolveStorePath(config.session?.store, {
            agentId: route.agentId,
        });
        const envelopeOptions = core.channel.reply.resolveEnvelopeFormatOptions(config);
        const previousTimestamp = core.channel.session.readSessionUpdatedAt({
            storePath,
            sessionKey: route.sessionKey,
        });

        const body = core.channel.reply.formatAgentEnvelope({
            channel: "QQ",
            from: fromLabel,
            timestamp: new Date(message.timestamp).getTime(),
            previousTimestamp,
            envelope: envelopeOptions,
            body: rawBody,
        });

        const ctxPayload = core.channel.reply.finalizeInboundContext({
            Body: body,
            RawBody: rawBody,
            CommandBody: rawBody,
            From: isGroup ? `qq:group:${chatId}` : `qq:${senderId}`,
            To: `qq:${chatId}`,
            SessionKey: route.sessionKey,
            AccountId: route.accountId,
            ChatType: isGroup ? "group" : "direct",
            ConversationLabel: fromLabel,
            SenderId: senderId,
            Provider: "qq",
            Surface: "qq",
            MessageSid: message.id,
            OriginatingChannel: "qq",
            OriginatingTo: `qq:${chatId}`,
        });

        await core.channel.session.recordInboundSession({
            storePath,
            sessionKey: ctxPayload.SessionKey ?? route.sessionKey,
            ctx: ctxPayload,
            onRecordError: (err) => {
                log?.error(`[${account.accountId}] Failed updating session: ${String(err)}`);
            },
        });

        const tableMode = core.channel.text.resolveMarkdownTableMode({
            cfg: config,
            channel: "qq",
            accountId: account.accountId,
        });

        await core.channel.reply.dispatchReplyWithBufferedBlockDispatcher({
            ctx: ctxPayload,
            cfg: config,
            dispatcherOptions: {
                deliver: async (payload) => {
                    await deliverQQReply({
                        payload,
                        token,
                        chatType,
                        chatId,
                        msgId: message.id,
                        tableMode,
                    });
                },
                onError: (err, info) => {
                    log?.error(
                        `[${account.accountId}] QQ ${info.kind} reply failed: ${String(err)}`,
                    );
                },
            },
        });
    };

    const deliverQQReply = async (params: {
        payload: { text?: string; mediaUrls?: string[]; mediaUrl?: string };
        token: string;
        chatType: "c2c" | "group";
        chatId: string;
        msgId?: string;
        tableMode?: MarkdownTableMode;
    }): Promise<void> => {
        const { payload, token, chatType, chatId, msgId } = params;
        const tableMode = params.tableMode ?? "code";
        const text = core.channel.text.convertMarkdownTables(payload.text ?? "", tableMode);

        if (!text) return;

        const chunkMode = core.channel.text.resolveChunkMode(config, "qq", account.accountId);
        const chunks = core.channel.text.chunkMarkdownTextWithMode(
            text,
            QQ_TEXT_LIMIT,
            chunkMode,
        );

        const sendFn = chatType === "c2c" ? sendC2CMessage : sendGroupMessage;

        for (let i = 0; i < chunks.length; i++) {
            const chunk = chunks[i];
            try {
                await sendFn(token, chatId, {
                    content: chunk,
                    msg_type: 0,
                    msg_id: i === 0 ? msgId : undefined, // Only use msg_id for first chunk
                    msg_seq: i + 1,
                });
                statusSink?.({ lastOutboundAt: Date.now() });
            } catch (err) {
                log?.error(`[${account.accountId}] QQ message send failed: ${String(err)}`);
            }
        }
    };

    // Start initial connection
    await connect();

    return { stop };
}