// Core server: HTTP + WebSocket + SSE

import type { ServerWebSocket } from "bun";
import {
  appendOutput,
  createPrompt,
  createSession,
  endSession,
  getActiveSessions,
  getDeviceBySecret,
  getPrompt,
  getSession,
  initDb,
  respondToPrompt,
  updateLastSeen,
} from "./db";
import type {
  AnswerResponse,
  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, clean up
      console.debug("SSE client write error:", error);
      sseClients.delete(controller);
    }
  }
}

// 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") {
      let ctrl: ReadableStreamDefaultController<string>;
      const stream = new ReadableStream<string>({
        start(controller) {
          ctrl = controller;
          sseClients.add(controller);
          // Send initial headers
          controller.enqueue(": connected\n\n");
        },
        cancel() {
          sseClients.delete(ctrl);
        },
      });

      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);
    }

    // Create prompt for a session
    if (
      url.pathname.match(/^\/api\/sessions\/\d+\/prompts$/) &&
      req.method === "POST"
    ) {
      const parts = url.pathname.split("/");
      const sessionId = Number.parseInt(parts[3] || "", 10);

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

      const session = getSession(sessionId);
      if (!session) {
        return new Response("Session not found", { status: 404 });
      }

      const body = (await req.json()) as { prompt_text?: unknown };
      if (!body.prompt_text || typeof body.prompt_text !== "string") {
        return new Response("Missing or invalid prompt_text", { status: 400 });
      }

      const prompt = createPrompt(sessionId, body.prompt_text);

      // Broadcast to dashboards
      broadcastSSE({
        type: "prompt",
        prompt_id: prompt.id,
        session_id: sessionId,
        prompt_text: prompt.prompt_text,
        prompt_json: prompt.prompt_json
          ? JSON.stringify(prompt.prompt_json)
          : null,
      });

      return Response.json(prompt);
    }

    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 });
      }

      // New unified answer endpoint
      if (url.pathname.endsWith("/answer") && 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 });
        }

        const body = (await req.json()) as { response?: unknown };
        if (!body.response || typeof body.response !== "object") {
          return new Response("Missing or invalid response", { status: 400 });
        }

        const answer = body.response as AnswerResponse;
        let inputData: string;

        // Handle each response type
        if (answer.type === "option") {
          inputData = `${answer.value}\n`;
        } else if (answer.type === "text") {
          inputData = `${answer.value}\n`;
        } else if (answer.type === "tab_instructions") {
          // Execute key sequence for tab instructions with delays:
          // 1. Navigate to selected_option (up/down arrows)
          // 2. Wait 100ms
          // 3. Send Tab key
          // 4. Wait 100ms
          // 5. Write instruction text
          // 6. Send Enter key

          const promptData = prompt.prompt_json;
          if (!promptData || promptData.prompt_type !== "permission") {
            return new Response("Tab instructions only valid for permission prompts", { status: 400 });
          }

          const currentOption = promptData.selected_option;
          const targetOption = answer.selected_option;

          // Mark as responded in DB first
          respondToPrompt(
            promptId,
            `tab:${answer.selected_option}`,
          );

          // Broadcast to dashboards
          broadcastSSE({
            type: "prompt_response",
            prompt_id: promptId,
            response: answer.selected_option === 1 ? "approve" : "reject",
          });

          // Get WebSocket for async execution
          const ws = sessionWebSockets.get(prompt.session_id);
          if (!ws) {
            return new Response("Session WebSocket not found", { status: 404 });
          }

          // Execute key sequence asynchronously with delays
          (async () => {
            const sendInput = (data: string) => {
              const message: ServerMessage = { type: "input", data };
              ws.send(JSON.stringify(message));
            };

            // Navigate to target option
            const diff = targetOption - currentOption;
            const arrow = diff > 0 ? '\x1b[B' : '\x1b[A';
            for (let i = 0; i < Math.abs(diff); i++) {
              sendInput(arrow);
              await Bun.sleep(50); // Small delay between arrows
            }

            await Bun.sleep(100);
            sendInput('\t'); // Tab key

            await Bun.sleep(100);
            sendInput(answer.instruction); // Instruction text
            sendInput('\n'); // Enter key
          })().catch((err) => {
            console.error("Error executing tab instruction sequence:", err);
          });

          // Return immediately (async execution continues in background)
          return Response.json({ success: true });
        } else {
          return new Response("Invalid response type", { status: 400 });
        }

        // Mark as responded in DB
        respondToPrompt(
          promptId,
          answer.type === "option" ? answer.value : "custom",
        );

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

        // Broadcast to dashboards
        broadcastSSE({
          type: "prompt_response",
          prompt_id: promptId,
          response:
            answer.type === "option" && answer.value === "1"
              ? "approve"
              : "reject",
        });

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

      // Legacy approve endpoint (backward compatibility)
      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 (using "1\n" for option 1)
        const ws = sessionWebSockets.get(prompt.session_id);
        if (ws) {
          const message: ServerMessage = { type: "input", data: "1\n" };
          ws.send(JSON.stringify(message));
        }

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

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

      // Legacy reject endpoint (backward compatibility)
      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 (using "3\n" for option 3)
        const ws = sessionWebSockets.get(prompt.session_id);
        if (ws) {
          const message: ServerMessage = { type: "input", data: "3\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.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.close(1008, "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 prompt message
        if (msg.type === "prompt") {
          const prompt = createPrompt(msg.session_id, msg.prompt_text);
          broadcastSSE({
            type: "prompt",
            prompt_id: prompt.id,
            session_id: msg.session_id,
            prompt_text: msg.prompt_text,
            prompt_json: prompt.prompt_json
              ? JSON.stringify(prompt.prompt_json)
              : null,
          });
          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.close(1008, "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 };