import http from "node:http";
import fs from "node:fs/promises";
import path from "node:path";
import { fileURLToPath } from "node:url";
import { WebSocketServer, WebSocket } from "ws";
import { queryServerList } from "./masterQuery.js";
import { GameConnection } from "./gameConnection.js";
import { loadCredentials } from "./auth.js";
import { relayLog } from "./logger.js";
import type { ClientMessage, ServerMessage, ServerInfo } from "./types.js";

const __dirname = path.dirname(fileURLToPath(import.meta.url));
/** Base path for game files (extracted VL2 contents). */
const GAME_BASE_PATH =
  process.env.GAME_BASE_PATH || path.resolve(__dirname, "..", "docs", "base");

const MANIFEST_PATH =
  process.env.MANIFEST_PATH ||
  path.resolve(GAME_BASE_PATH, "..", "..", "public", "manifest.json");

const RELAY_PORT = parseInt(process.env.RELAY_PORT || "8765", 10);
const MASTER_SERVER =
  process.env.T2_MASTER_SERVER || "master.tribesnext.com";

/** HTTP server for health checks; WebSocket upgrades are handled separately. */
const httpServer = http.createServer(async (req, res) => {
  if (req.url === "/health") {
    const checks: Record<string, { ok: boolean; detail?: string }> = {};

    // Check game assets directory.
    try {
      const stat = await fs.stat(GAME_BASE_PATH);
      const entries = await fs.readdir(GAME_BASE_PATH);
      checks.gameAssets = {
        ok: stat.isDirectory() && entries.length > 0,
        detail: `${entries.length} entries in ${GAME_BASE_PATH}`,
      };
    } catch {
      checks.gameAssets = { ok: false, detail: `${GAME_BASE_PATH} not found` };
    }

    // Check manifest.
    try {
      const raw = await fs.readFile(MANIFEST_PATH, "utf-8");
      const manifest = JSON.parse(raw);
      const count = Object.keys(manifest.resources ?? {}).length;
      checks.manifest = { ok: count > 0, detail: `${count} resources` };
    } catch {
      checks.manifest = { ok: false, detail: `${MANIFEST_PATH} not found` };
    }

    // Check credentials.
    const creds = loadCredentials();
    checks.credentials = {
      ok: creds !== null,
      detail: creds ? "loaded" : "missing or incomplete",
    };

    const allOk = Object.values(checks).every((c) => c.ok);
    res.writeHead(allOk ? 200 : 503, { "Content-Type": "application/json" });
    res.end(JSON.stringify({ status: allOk ? "ok" : "degraded", checks }, null, 2));
    return;
  }

  res.writeHead(404);
  res.end();
});

const wss = new WebSocketServer({ server: httpServer });
httpServer.listen(RELAY_PORT, "0.0.0.0", () => {
  relayLog.info({ port: RELAY_PORT }, "Relay server listening");
});

/** Cached server list from the most recent master query. */
let cachedServers: ServerInfo[] = [];

wss.on("connection", (ws) => {
  relayLog.info("Browser client connected");

  let gameConnection: GameConnection | null = null;
  let lastJoinAddress: string | null = null;
  let retryCount = 0;
  let retryTimer: ReturnType<typeof setTimeout> | null = null;

  const MAX_RETRIES = 3;
  const RETRY_DELAY_MS = 6000;
  const RETRYABLE_REASONS = ["Server is cycling mission"];

  async function connectToServer(ws: WebSocket, address: string): Promise<void> {
    if (gameConnection) {
      gameConnection.disconnect();
    }

    gameConnection = new GameConnection(address);

    // Set mapName from the cached server list if available.
    const cachedServer = cachedServers.find(
      (s) => s.address === address,
    );
    if (cachedServer?.mapName) {
      gameConnection.setMapName(cachedServer.mapName);
    }

    gameConnection.on("status", (status, statusMessage) => {
      relayLog.info(
        {
          status,
          statusMessage,
          connectSequence: gameConnection?.connectSequence,
          mapName: gameConnection?.mapName,
        },
        "Game connection status changed",
      );

      // Auto-retry on retryable disconnect reasons.
      if (
        status === "disconnected" &&
        statusMessage &&
        RETRYABLE_REASONS.some((r) => statusMessage.includes(r)) &&
        retryCount < MAX_RETRIES &&
        lastJoinAddress === address
      ) {
        retryCount++;
        relayLog.info(
          { attempt: retryCount, maxRetries: MAX_RETRIES, delay: RETRY_DELAY_MS },
          "Retryable disconnect — will reconnect",
        );
        sendToClient(ws, {
          type: "status",
          status: "connecting",
          message: `${statusMessage} — retrying (${retryCount}/${MAX_RETRIES})...`,
          connectSequence: gameConnection?.connectSequence,
          mapName: gameConnection?.mapName,
        });
        retryTimer = setTimeout(() => {
          retryTimer = null;
          if (lastJoinAddress === address && ws.readyState === WebSocket.OPEN) {
            connectToServer(ws, address);
          }
        }, RETRY_DELAY_MS);
        return;
      }

      sendToClient(ws, {
        type: "status",
        status,
        message: statusMessage,
        connectSequence: gameConnection?.connectSequence,
        mapName: gameConnection?.mapName,
      });
    });

    gameConnection.on("ping", (ms) => {
      sendToClient(ws, { type: "ping", ms });
    });

    let forwardedPackets = 0;
    gameConnection.on("packet", (packetData) => {
      forwardedPackets++;
      if (ws.readyState === WebSocket.OPEN) {
        ws.send(packetData, { binary: true });
      } else {
        relayLog.warn(
          { wsState: ws.readyState, total: forwardedPackets },
          "Dropped game packet — WebSocket not open",
        );
      }
      if (forwardedPackets <= 5 || forwardedPackets % 500 === 0) {
        relayLog.debug(
          { bytes: packetData.length, total: forwardedPackets },
          "Forwarded game packet to browser",
        );
      }
    });

    gameConnection.on("error", (err) => {
      relayLog.error({ err }, "Game connection error");
      sendToClient(ws, {
        type: "error",
        message: err.message,
      });
    });

    gameConnection.on("close", () => {
      relayLog.info("Game connection closed");
      gameConnection = null;
    });

    await gameConnection.connect();
  }

  ws.on("message", async (data, isBinary) => {
    try {
      if (isBinary) {
        return;
      }

      const message: ClientMessage = JSON.parse(data.toString());
      await handleClientMessage(ws, message);
    } catch (e) {
      const err = e instanceof Error ? e.message : String(e);
      relayLog.error({ err: e }, "Error handling client message");
      sendToClient(ws, { type: "error", message: err });
    }
  });

  ws.on("close", () => {
    relayLog.info("Browser client disconnected");
    if (retryTimer) {
      clearTimeout(retryTimer);
      retryTimer = null;
    }
    if (gameConnection) {
      gameConnection.disconnect();
      gameConnection = null;
    }
  });

  async function handleClientMessage(
    ws: WebSocket,
    message: ClientMessage,
  ): Promise<void> {
    switch (message.type) {
      case "listServers": {
        relayLog.info("Querying master server for server list");
        try {
          const servers = await queryServerList(MASTER_SERVER);
          cachedServers = servers;
          relayLog.info(
            { count: servers.length },
            "Returning server list to browser",
          );
          sendToClient(ws, { type: "serverList", servers });
        } catch (e) {
          relayLog.error({ err: e }, "Master query failed");
          sendToClient(ws, {
            type: "error",
            message: `Master query failed: ${e}`,
          });
        }
        break;
      }

      case "joinServer": {
        relayLog.info({ address: message.address }, "Join server requested");
        if (gameConnection) {
          relayLog.info("Disconnecting existing game connection");
          gameConnection.disconnect();
        }
        if (retryTimer) {
          clearTimeout(retryTimer);
          retryTimer = null;
        }
        retryCount = 0;
        lastJoinAddress = message.address;

        await connectToServer(ws, message.address);
        break;
      }

      case "disconnect": {
        relayLog.info("Disconnect requested");
        if (retryTimer) {
          clearTimeout(retryTimer);
          retryTimer = null;
        }
        if (gameConnection) {
          gameConnection.disconnect();
          gameConnection = null;
        }
        break;
      }

      case "sendCommand": {
        if (gameConnection) {
          const authEvents = [
            "t2csri_pokeClient",
            "t2csri_getChallengeChunk",
            "t2csri_decryptChallenge",
          ];
          if (authEvents.includes(message.command)) {
            relayLog.debug(
              { event: message.command },
              "Forwarding auth event from browser",
            );
            gameConnection.handleAuthEvent(
              message.command,
              message.args,
            );
          } else {
            relayLog.debug(
              { command: message.command },
              "Forwarding command to server",
            );
            gameConnection.sendCommand(message.command, ...message.args);
          }
        }
        break;
      }

      case "sendCRCResponse": {
        if (gameConnection) {
          relayLog.debug("Forwarding CRC response from browser (legacy echo)");
          gameConnection.handleCRCChallenge(
            message.crcValue,
            message.field1,
            message.field2,
          );
        }
        break;
      }

      case "sendCRCCompute": {
        if (gameConnection) {
          relayLog.info(
            { datablocks: message.datablocks.length, includeTextures: message.includeTextures },
            "Computing CRC from game files",
          );
          gameConnection.computeAndSendCRC(
            message.seed,
            message.field2,
            message.datablocks,
            message.includeTextures,
            GAME_BASE_PATH,
          );
        }
        break;
      }

      case "sendGhostAck": {
        if (gameConnection) {
          relayLog.debug("Forwarding ghost ack from browser");
          gameConnection.handleGhostAlwaysDone(
            message.sequence,
            message.ghostCount,
          );
        }
        break;
      }

      case "wsPing": {
        sendToClient(ws, { type: "wsPong", ts: message.ts });
        break;
      }

      case "sendMove": {
        if (gameConnection) {
          gameConnection.sendMove({
            x: message.move.x,
            y: message.move.y,
            z: message.move.z,
            yaw: message.move.yaw,
            pitch: message.move.pitch,
            roll: message.move.roll,
            freeLook: message.move.freeLook,
            trigger: message.move.trigger,
          });
        }
        break;
      }
    }
  }
});

function sendToClient(ws: WebSocket, message: ServerMessage): void {
  if (ws.readyState === WebSocket.OPEN) {
    ws.send(JSON.stringify(message));
  }
}