import type { Socket } from "socket.io";
import { Server as SocketIOServer } from "socket.io";
import type { Server as HTTPServer } from "http";
import * as schema from "~/database/schema";
import { eq, and, asc } from "drizzle-orm";
import { checkOvernightPause } from "./overnight-pause-check";
import { calculatePickInfo } from "~/models/draft-utils";
import { logger } from "./logger";
import { db } from "./db";
import { msToSeconds } from "~/lib/draft-timer";

// Socket event types
interface ServerToClientEvents {
  "test-message": (data: {
    originalMessage: unknown;
    serverResponse: string;
    serverTimestamp: string;
    socketId: string;
  }) => void;
  "pick-made": (data: unknown) => void;
  "draft-started": (data: { seasonId: string; currentPickNumber: number }) => void;
  "draft-completed": () => void;
  "draft-room-closed": () => void;
  "timer-bank-updated": (data: { teamId: string; timeRemaining: number }) => void;
  "timer-pick-started": (data: {
    seasonId: string;
    teamId: string;
    pickNumber: number;
    expiresAt: number; // ms timestamp
    timeRemaining: number; // seconds remaining at emit time
  }) => void;
  "timer-overnight-paused": (data: {
    seasonId: string;
    teamId: string;
    resumesAtUTC?: number;
  }) => void;
  "autodraft-updated": (data: {
    teamId: string;
    isEnabled: boolean;
    mode: "next_pick" | "while_on";
    queueOnly: boolean;
    source?: "commissioner" | "user";
    reason?: "queue_empty" | "pick_complete";
  }) => void;
  "team-connected": (data: { teamId: string }) => void;
  "team-disconnected": (data: { teamId: string }) => void;
  "connected-teams-list": (data: { teamIds: string[] }) => void;
  "draft-paused": (data: { seasonId: string; paused: boolean; timers?: Array<{ teamId: string; timeRemaining: number }> }) => void;
  "draft-resumed": (data: { seasonId: string; paused: boolean }) => void;
  "participant-removed-from-queues": (data: { participantId: string }) => void;
  "queue-updated": (data: { queue: Array<{ id: string; teamId: string; seasonId: string; participantId: string; queuePosition: number }> }) => void;
  "watchlist-updated": (data: { participantIds: string[] }) => void;
  "brackt-evs-updated": (data: {
    updates: Array<{ participantId: string; expectedValue: number; vorpValue: number }>;
  }) => void;
  "draft-state-sync": (data: {
    currentPickNumber: number;
    isPaused: boolean;
    status: string;
    isOvernightPause: boolean;
    overnightResumesAt?: number;
    picks: Array<{
      id: string;
      pickNumber: number;
      round: number;
      pickInRound: number;
      timeUsed: number;
      team: unknown;
      participant: unknown;
      sport: unknown;
    }>;
    timers: Array<{
      teamId: string;
      timeRemaining: number;
      expiresAt?: number; // ms timestamp; present for the currently-active team
    }>;
    queue?: Array<{
      id: string;
      teamId: string;
      seasonId: string;
      participantId: string;
      queuePosition: number;
    }>;
    watchlistParticipantIds?: string[];
  }) => void;
}

interface ClientToServerEvents {
  "join-draft": (seasonId: string, teamId?: string) => void;
  "leave-draft": (seasonId: string) => void;
  "test-event": (data: unknown) => void;
}

// Global type augmentation
declare global {
  var __socketIO: SocketIOServer | undefined;
}

let io: SocketIOServer<ClientToServerEvents, ServerToClientEvents> | null = null;

function scheduleDraftRoomClosure(seasonId: string) {
  if (draftRoomClosureTimers.has(seasonId)) return;

  const timeout = setTimeout(() => {
    logger.log(`[Socket] Draft room closure: emitting draft-room-closed for ${seasonId}`);
    io?.to(`draft-${seasonId}`).emit("draft-room-closed");
    draftRoomClosureTimers.delete(seasonId);
  }, ROOM_CLOSURE_DELAY_MS);

  draftRoomClosureTimers.set(seasonId, timeout);
}

export { scheduleDraftRoomClosure };

// Track connected teams per season (in-memory, single-instance only).
// If the server restarts or runs as multiple instances this map resets.
// For multi-instance deployments, replace with a Redis-backed Socket.IO adapter.
const connectedTeams = new Map<string, Set<string>>(); // seasonId -> Set<teamId>

const ROOM_CLOSURE_DELAY_MS = 5 * 60 * 1000; // 5 minutes
const draftRoomClosureTimers = new Map<string, NodeJS.Timeout>(); // seasonId -> timeout

/**
 * Initialize Socket.IO server
 */
export function initializeSocketIO(httpServer: HTTPServer): SocketIOServer {
  if (io) {
    logger.log("Socket.IO already initialized");
    return io;
  }

  // Create typed Socket.IO server
  io = new SocketIOServer<ClientToServerEvents, ServerToClientEvents>(httpServer, {
    // Faster dead-connection detection than the defaults (20s/25s).
    // pingTimeout: how long to wait for a pong before declaring the connection dead.
    // pingInterval: how often to send a ping.
    // Together these detect a crashed server in ~15s instead of ~45s.
    // Trade-off: more heartbeat traffic at scale; revisit if server load becomes a concern.
    pingTimeout: 5000,
    pingInterval: 10000,
    cors: process.env.NODE_ENV === "production" && process.env.APP_URL
      ? {
          origin: process.env.APP_URL,
          credentials: true,
        }
      : undefined,
  });

  // Connection handling
  io.on("connection", (socket: Socket<ClientToServerEvents, ServerToClientEvents>) => {
    logger.log("Client connected:", socket.id);

    // Store team ID for this socket
    let currentTeamId: string | undefined;
    let currentSeasonId: string | undefined;

    socket.on("join-draft", async (seasonId: string, teamId?: string) => {
      if (!seasonId) {
        logger.error("No seasonId provided for join-draft");
        return;
      }

      try {
        const seasonData = await db.query.seasons.findFirst({
          where: eq(schema.seasons.id, seasonId),
          columns: { id: true, status: true, draftCompletedAt: true },
        });

        if (seasonData?.draftCompletedAt) {
          const elapsed = Date.now() - seasonData.draftCompletedAt.getTime();
          if (elapsed >= ROOM_CLOSURE_DELAY_MS) {
            socket.emit("draft-room-closed");
            logger.log(`[Socket] join-draft rejected for ${seasonId}: room closed (completed ${Math.round(elapsed / 60000)}m ago)`);
            return;
          }

          if (!draftRoomClosureTimers.has(seasonId)) {
            const remaining = ROOM_CLOSURE_DELAY_MS - elapsed;
            const timeout = setTimeout(() => {
              logger.log(`[Socket] Draft room closure: emitting draft-room-closed for ${seasonId}`);
              io?.to(`draft-${seasonId}`).emit("draft-room-closed");
              draftRoomClosureTimers.delete(seasonId);
            }, remaining);
            draftRoomClosureTimers.set(seasonId, timeout);
          }
        }
      } catch (err) {
        logger.error("[Socket] join-draft room-closure check failed:", err);
      }

      socket.join(`draft-${seasonId}`);
      currentSeasonId = seasonId;
      logger.log(`Socket ${socket.id} joined draft-${seasonId}`);

      // If teamId provided, validate it belongs to this season before tracking
      if (teamId) {
        try {
          const team = await db.query.teams.findFirst({
            where: and(eq(schema.teams.id, teamId), eq(schema.teams.seasonId, seasonId)),
          });
          if (!team) {
            logger.warn(`[Socket] join-draft rejected: team ${teamId} does not belong to season ${seasonId}`);
            return;
          }
        } catch (err) {
          logger.error("[Socket] join-draft team validation failed:", err);
          return;
        }

        currentTeamId = teamId;
        socket.join(`team-${teamId}`);

        // Initialize the season's connected teams set if it doesn't exist
        if (!connectedTeams.has(seasonId)) {
          connectedTeams.set(seasonId, new Set());
        }

        // Get current connected teams for this season
        const seasonConnectedTeams = connectedTeams.get(seasonId) ?? new Set<string>();
        if (!connectedTeams.has(seasonId)) connectedTeams.set(seasonId, seasonConnectedTeams);

        // Send the list of already-connected teams to this socket
        socket.emit("connected-teams-list", { teamIds: Array.from(seasonConnectedTeams) });

        // Add this team to the connected teams set
        seasonConnectedTeams.add(teamId);

        // Broadcast to everyone else that this team connected
        io?.to(`draft-${seasonId}`).emit("team-connected", { teamId });
        logger.log(`Team ${teamId} connected to draft-${seasonId}. Total connected: ${seasonConnectedTeams.size}`);
      }

      // Send full draft state to the joining client so it can sync immediately.
      // This is critical for mobile reconnection: the client may have been in the
      // background for minutes/hours and missed many picks. The revalidate() path
      // (HTTP loader re-fetch) covers this too, but it can fail due to expired auth
      // tokens or flaky mobile networks. This socket-based sync provides an
      // additional, more reliable path since the socket is already connected.
      try {
        const [seasonData, picks, timerRows, draftSlots, queueItems, watchlistItems] = await Promise.all([
          db.query.seasons.findFirst({
            where: eq(schema.seasons.id, seasonId),
          }),
          db
            .select({
              id: schema.draftPicks.id,
              pickNumber: schema.draftPicks.pickNumber,
              round: schema.draftPicks.round,
              pickInRound: schema.draftPicks.pickInRound,
              timeUsed: schema.draftPicks.timeUsed,
              team: schema.teams,
              participant: schema.seasonParticipants,
              sport: schema.sports,
            })
            .from(schema.draftPicks)
            .innerJoin(schema.teams, eq(schema.draftPicks.teamId, schema.teams.id))
            .innerJoin(
              schema.seasonParticipants,
              eq(schema.draftPicks.participantId, schema.seasonParticipants.id)
            )
            .innerJoin(
              schema.sportsSeasons,
              eq(schema.seasonParticipants.sportsSeasonId, schema.sportsSeasons.id)
            )
            .innerJoin(
              schema.sports,
              eq(schema.sportsSeasons.sportId, schema.sports.id)
            )
            .where(eq(schema.draftPicks.seasonId, seasonId))
            .orderBy(asc(schema.draftPicks.pickNumber)),
          db.query.draftTimers.findMany({
            where: eq(schema.draftTimers.seasonId, seasonId),
          }),
          db.query.draftSlots.findMany({
            where: eq(schema.draftSlots.seasonId, seasonId),
            orderBy: asc(schema.draftSlots.draftOrder),
          }),
          teamId
            ? db.query.draftQueue.findMany({
                where: and(
                  eq(schema.draftQueue.teamId, teamId),
                  eq(schema.draftQueue.seasonId, seasonId)
                ),
                orderBy: asc(schema.draftQueue.queuePosition),
              })
            : Promise.resolve([]),
          teamId
            ? db.query.watchlist.findMany({
                where: and(
                  eq(schema.watchlist.teamId, teamId),
                  eq(schema.watchlist.seasonId, seasonId)
                ),
              })
            : Promise.resolve([]),
        ]);

        if (seasonData) {
          // Compute overnight-pause state so reconnecting clients see it immediately.
          let isOvernightPause = false;
          let overnightResumesAt: number | undefined;

          if (
            draftSlots.length > 0 &&
            seasonData.status === "draft" &&
            !seasonData.draftPaused
          ) {
            const { pickInRound } = calculatePickInfo(
              seasonData.currentPickNumber ?? 1,
              draftSlots.length
            );
            const currentSlot = draftSlots.find((s) => s.draftOrder === pickInRound);
            if (currentSlot) {
              const result = await checkOvernightPause(seasonData, currentSlot.teamId);
              isOvernightPause = result.active;
              overnightResumesAt = result.resumesAtUTC;
            }
          }

          socket.emit("draft-state-sync", {
            currentPickNumber: seasonData.currentPickNumber || 1,
            isPaused: seasonData.draftPaused || false,
            status: seasonData.status,
            isOvernightPause,
            overnightResumesAt,
            picks,
            timers: timerRows.map((t) => {
              const nowMs = Date.now();
              const expiresAt = t.picksExpiresAt?.getTime();
              const computedRemaining =
                expiresAt && expiresAt > nowMs
                  ? msToSeconds(expiresAt - nowMs)
                  : t.timeRemaining;
              return {
                teamId: t.teamId,
                timeRemaining: computedRemaining,
                expiresAt: expiresAt && expiresAt > nowMs ? expiresAt : undefined,
              };
            }),
            queue: teamId ? queueItems : undefined,
            watchlistParticipantIds: teamId ? watchlistItems.map((w) => w.participantId) : undefined,
          });
        }
      } catch (err) {
        logger.error("[Socket] draft-state-sync query failed:", err);
        // Non-fatal — the client will fall back to HTTP revalidation
      }
    });

    socket.on("leave-draft", (seasonId: string) => {
      if (!seasonId) return;
      socket.leave(`draft-${seasonId}`);
      logger.log(`Socket ${socket.id} left draft-${seasonId}`);

      // Emit disconnection event if team was tracked
      if (currentTeamId) {
        socket.leave(`team-${currentTeamId}`);

        // Remove team from connected teams tracking
        const seasonConnectedTeams = connectedTeams.get(seasonId);
        if (seasonConnectedTeams) {
          seasonConnectedTeams.delete(currentTeamId);
          logger.log(`Team ${currentTeamId} removed from tracking. Remaining: ${seasonConnectedTeams.size}`);

          // Clean up empty sets
          if (seasonConnectedTeams.size === 0) {
            connectedTeams.delete(seasonId);
          }
        }

        io?.to(`draft-${seasonId}`).emit("team-disconnected", { teamId: currentTeamId });
        logger.log(`Team ${currentTeamId} disconnected from draft-${seasonId}`);
      }
    });

    socket.on("test-event", (data: unknown) => {
      logger.log("📨 Received test-event from client:", socket.id, data);
      
      socket.emit("test-message", {
        originalMessage: data,
        serverResponse: "Hello from server!",
        serverTimestamp: new Date().toISOString(),
        socketId: socket.id,
      });
      
      logger.log("✅ Sent test-message response to client:", socket.id);
    });

    socket.on("disconnect", () => {
      logger.log("Client disconnected:", socket.id);

      // Emit disconnection event if team was tracked
      if (currentTeamId && currentSeasonId) {
        // Remove team from connected teams tracking
        const seasonConnectedTeams = connectedTeams.get(currentSeasonId);
        if (seasonConnectedTeams) {
          seasonConnectedTeams.delete(currentTeamId);
          logger.log(`Team ${currentTeamId} removed from tracking on disconnect. Remaining: ${seasonConnectedTeams.size}`);

          // Clean up empty sets
          if (seasonConnectedTeams.size === 0) {
            connectedTeams.delete(currentSeasonId);
          }
        }

        io?.to(`draft-${currentSeasonId}`).emit("team-disconnected", { teamId: currentTeamId });
        logger.log(`Team ${currentTeamId} disconnected from draft-${currentSeasonId}`);
      }
    });
  });

  // Store globally for route handlers
  global.__socketIO = io;

  logger.log("Socket.IO initialized");

  // Start the draft timer system (async import but don't await)
  import("./timer").then(({ startDraftTimerSystem }) => {
    startDraftTimerSystem();
  }).catch((error) => {
    logger.error("Failed to start timer system:", error);
  });

  return io;
}

/**
 * Get the Socket.IO server instance
 */
export function getSocketIO(): SocketIOServer {
  const instance = io || global.__socketIO;
  if (!instance) {
    throw new Error("Socket.IO not initialized. Call initializeSocketIO first.");
  }
  return instance;
}