// Core server: HTTP + WebSocket + SSE

import type { ServerWebSocket } from "bun";
import {
  appendOutput,
  createSession,
  endSession,
  getActiveSessions,
  getDeviceBySecret,
  getPrompt,
  initDb,
  respondToPrompt,
  updateLastSeen,
} from "./db";
import type { ClientMessage, ServerMessage, SSEEvent } from "./types";

// Server state
const sseClients = new Set<ReadableStreamDefaultController<string>>();
const sessionWebSockets = new Map<number, ServerWebSocket<SessionData>>();

interface SessionData {
  deviceId: number;
  sessionId: number | null;
}

// Broadcast SSE event to all connected dashboards
function broadcastSSE(event: SSEEvent): void {
  const eventStr = `event: ${event.type}\ndata: ${JSON.stringify(event)}\n\n`;
  for (const controller of sseClients) {
    try {
      controller.enqueue(eventStr);
    } catch (error) {
      // Client disconnected, will be cleaned up
      console.debug("SSE client write error:", error);
    }
  }
}

// Initialize database
const port = Number.parseInt(process.env.PORT || "3000", 10);
initDb();

// Start server
const server = Bun.serve<SessionData>({
  port,
  async fetch(req, server) {
    const url = new URL(req.url);

    // Upgrade WebSocket connections
    if (url.pathname === "/ws") {
      const upgraded = server.upgrade(req, {
        data: { deviceId: 0, sessionId: null },
      });
      if (!upgraded) {
        return new Response("WebSocket upgrade failed", { status: 400 });
      }
      return undefined;
    }

    // SSE endpoint for dashboard
    if (url.pathname === "/events") {
      const stream = new ReadableStream<string>({
        start(controller) {
          sseClients.add(controller);
          // Send initial headers
          controller.enqueue(": connected\n\n");
        },
        cancel() {
          sseClients.delete(
            this as unknown as ReadableStreamDefaultController<string>,
          );
        },
      });

      return new Response(stream, {
        headers: {
          "Content-Type": "text/event-stream",
          "Cache-Control": "no-cache",
          Connection: "keep-alive",
        },
      });
    }

    // REST API endpoints
    if (url.pathname === "/api/sessions" && req.method === "GET") {
      const sessions = getActiveSessions();
      return Response.json(sessions);
    }

    if (url.pathname.startsWith("/api/prompts/")) {
      const parts = url.pathname.split("/");
      const promptId = Number.parseInt(parts[3] || "", 10);

      if (Number.isNaN(promptId)) {
        return new Response("Invalid prompt ID", { status: 400 });
      }

      if (url.pathname.endsWith("/approve") && req.method === "POST") {
        const prompt = getPrompt(promptId);
        if (!prompt) {
          return new Response("Prompt not found", { status: 404 });
        }
        if (prompt.response !== null) {
          return new Response("Prompt already responded", { status: 400 });
        }

        respondToPrompt(promptId, "approve");

        // Notify CLI via WebSocket
        const ws = sessionWebSockets.get(prompt.session_id);
        if (ws) {
          const message: ServerMessage = { type: "input", data: "y\n" };
          ws.send(JSON.stringify(message));
        }

        // Broadcast to dashboards
        broadcastSSE({
          type: "prompt_response",
          prompt_id: promptId,
          response: "approve",
        });

        return Response.json({ success: true });
      }

      if (url.pathname.endsWith("/reject") && req.method === "POST") {
        const prompt = getPrompt(promptId);
        if (!prompt) {
          return new Response("Prompt not found", { status: 404 });
        }
        if (prompt.response !== null) {
          return new Response("Prompt already responded", { status: 400 });
        }

        respondToPrompt(promptId, "reject");

        // Notify CLI via WebSocket
        const ws = sessionWebSockets.get(prompt.session_id);
        if (ws) {
          const message: ServerMessage = { type: "input", data: "n\n" };
          ws.send(JSON.stringify(message));
        }

        // Broadcast to dashboards
        broadcastSSE({
          type: "prompt_response",
          prompt_id: promptId,
          response: "reject",
        });

        return Response.json({ success: true });
      }
    }

    // Serve static files from public/
    if (url.pathname === "/") {
      return new Response(Bun.file("public/index.html"));
    }

    // Handle other static files
    const filePath = `public${url.pathname}`;
    const file = Bun.file(filePath);
    if (await file.exists()) {
      return new Response(file);
    }

    return new Response("Not found", { status: 404 });
  },

  websocket: {
    open(_ws) {
      console.debug("WebSocket connected, awaiting auth");
    },

    async message(ws, message) {
      try {
        const msg: ClientMessage = JSON.parse(message.toString());

        // Handle auth message
        if (msg.type === "auth") {
          const device = getDeviceBySecret(msg.secret);
          if (!device) {
            ws.send(
              JSON.stringify({ type: "error", message: "Invalid secret" }),
            );
            ws.close(1008, "Invalid secret");
            return;
          }

          updateLastSeen(device.id);
          ws.data.deviceId = device.id;

          // Create new session
          const session = createSession(
            device.id,
            msg.cwd || null,
            msg.command || null,
          );
          ws.data.sessionId = session.id;
          sessionWebSockets.set(session.id, ws);

          console.debug(
            `Session ${session.id} started for device ${device.id}`,
          );

          // Broadcast session start
          broadcastSSE({
            type: "session_start",
            session_id: session.id,
            cwd: session.cwd,
            command: session.command,
          });

          ws.send(
            JSON.stringify({ type: "authenticated", session_id: session.id }),
          );
          return;
        }

        // All other messages require authentication
        if (!ws.data.sessionId) {
          ws.send(
            JSON.stringify({ type: "error", message: "Not authenticated" }),
          );
          return;
        }

        // Handle output message
        if (msg.type === "output") {
          appendOutput(ws.data.sessionId, msg.data);
          broadcastSSE({
            type: "output",
            session_id: ws.data.sessionId,
            data: msg.data,
          });
          return;
        }

        // Handle resize message
        if (msg.type === "resize") {
          // Store resize info if needed (not yet implemented)
          console.debug(
            `Session ${ws.data.sessionId} resized to ${msg.cols}x${msg.rows}`,
          );
          return;
        }

        // Handle exit message
        if (msg.type === "exit") {
          endSession(ws.data.sessionId);
          sessionWebSockets.delete(ws.data.sessionId);

          console.debug(
            `Session ${ws.data.sessionId} ended with code ${msg.code}`,
          );

          broadcastSSE({
            type: "session_end",
            session_id: ws.data.sessionId,
            exit_code: msg.code,
          });

          ws.close(1000, "Session ended");
          return;
        }
      } catch (error) {
        console.error("WebSocket message error:", error);
        ws.send(
          JSON.stringify({ type: "error", message: "Invalid message format" }),
        );
      }
    },

    close(ws) {
      if (ws.data.sessionId) {
        sessionWebSockets.delete(ws.data.sessionId);
        // Mark session as ended if not already
        const sessionId = ws.data.sessionId;
        endSession(sessionId);
        console.debug(`WebSocket closed for session ${sessionId}`);
      }
    },
  },
});

console.log(`Server listening on http://localhost:${port}`);

// Periodic ping to keep WebSocket connections alive (every 30s)
setInterval(() => {
  for (const ws of sessionWebSockets.values()) {
    try {
      const ping: ServerMessage = { type: "ping" };
      ws.send(JSON.stringify(ping));
    } catch (error) {
      console.debug("Ping error:", error);
    }
  }
}, 30_000);

export { server };