/**
 * Agent Sessions API
 *
 * POST /api/projects/[projectId]/agent/sessions
 *   Create a new agent session and kick it off via vibn-agent-runner.
 *   Body: { appName, appPath, task }
 *
 * GET /api/projects/[projectId]/agent/sessions
 *   List all sessions for a project, newest first.
 */
import { NextResponse } from "next/server";
import { getServerSession } from "next-auth";
import { authOptions } from "@/lib/auth/authOptions";
import { query } from "@/lib/db-postgres";

const AGENT_RUNNER_URL = process.env.AGENT_RUNNER_URL ?? "http://localhost:3333";

// Ensure the agent_sessions table exists (idempotent).
async function ensureTable() {
  await query(`
    CREATE TABLE IF NOT EXISTS agent_sessions (
      id              UUID PRIMARY KEY DEFAULT gen_random_uuid(),
      project_id      UUID NOT NULL,
      app_name        TEXT NOT NULL,
      app_path        TEXT NOT NULL,
      task            TEXT NOT NULL,
      plan            JSONB,
      status          TEXT NOT NULL DEFAULT 'pending',
      output          JSONB NOT NULL DEFAULT '[]'::jsonb,
      changed_files   JSONB NOT NULL DEFAULT '[]'::jsonb,
      error           TEXT,
      started_at      TIMESTAMPTZ,
      completed_at    TIMESTAMPTZ,
      created_at      TIMESTAMPTZ NOT NULL DEFAULT now(),
      updated_at      TIMESTAMPTZ NOT NULL DEFAULT now()
    );
    CREATE INDEX IF NOT EXISTS agent_sessions_project_idx
      ON agent_sessions(project_id, created_at DESC);
  `, []);
}

// ── POST — create session ────────────────────────────────────────────────────

export async function POST(
  req: Request,
  { params }: { params: Promise<{ projectId: string }> }
) {
  try {
    const { projectId } = await params;
    const session = await getServerSession(authOptions);
    if (!session?.user?.email) {
      return NextResponse.json({ error: "Unauthorized" }, { status: 401 });
    }

    const body = await req.json();
    const { appName, appPath, task } = body as {
      appName: string;
      appPath: string;
      task: string;
    };

    if (!appName || !appPath || !task?.trim()) {
      return NextResponse.json({ error: "appName, appPath and task are required" }, { status: 400 });
    }

    await ensureTable();

    // Verify ownership
    const owns = await query<{ id: string }>(
      `SELECT p.id FROM fs_projects p
       JOIN fs_users u ON u.id = p.user_id
       WHERE p.id = $1 AND u.data->>'email' = $2 LIMIT 1`,
      [projectId, session.user.email]
    );
    if (owns.length === 0) {
      return NextResponse.json({ error: "Project not found" }, { status: 404 });
    }

    // Create the session row
    const rows = await query<{ id: string }>(
      `INSERT INTO agent_sessions (project_id, app_name, app_path, task, status, started_at)
       VALUES ($1, $2, $3, $4, 'running', now())
       RETURNING id`,
      [projectId, appName, appPath, task.trim()]
    );
    const sessionId = rows[0].id;

    // Fire-and-forget: call agent-runner to start the execution loop
    // The agent runner is responsible for updating the session row as it works.
    fetch(`${AGENT_RUNNER_URL}/agent/execute`, {
      method: "POST",
      headers: { "Content-Type": "application/json" },
      body: JSON.stringify({
        sessionId,
        projectId,
        appName,
        appPath,
        task: task.trim(),
      }),
    }).catch(err => {
      // Agent runner may not be wired yet — log but don't fail
      console.warn("[agent] runner not reachable:", err.message);
      // Mark session as failed if runner unreachable
      query(
        `UPDATE agent_sessions
         SET status = 'failed',
             error = 'Agent runner not reachable',
             completed_at = now(),
             output = jsonb_build_array(jsonb_build_object(
               'ts', now()::text,
               'type', 'error',
               'text', 'Agent runner service is not connected yet. Phase 2 implementation pending.'
             ))
         WHERE id = $1`,
        [sessionId]
      ).catch(() => {});
    });

    return NextResponse.json({ sessionId }, { status: 201 });
  } catch (err) {
    console.error("[agent/sessions POST]", err);
    return NextResponse.json({ error: "Failed to create session" }, { status: 500 });
  }
}

// ── GET — list sessions ──────────────────────────────────────────────────────

export async function GET(
  req: Request,
  { params }: { params: Promise<{ projectId: string }> }
) {
  try {
    const { projectId } = await params;
    const session = await getServerSession(authOptions);
    if (!session?.user?.email) {
      return NextResponse.json({ error: "Unauthorized" }, { status: 401 });
    }

    await ensureTable();

    const sessions = await query<{
      id: string;
      app_name: string;
      task: string;
      status: string;
      created_at: string;
      started_at: string | null;
      completed_at: string | null;
      output: Array<{ ts: string; type: string; text: string }>;
      changed_files: Array<{ path: string; status: string }>;
      error: string | null;
    }>(
      `SELECT s.id, s.app_name, s.task, s.status,
              s.created_at, s.started_at, s.completed_at,
              s.output, s.changed_files, s.error
       FROM agent_sessions s
       JOIN fs_projects p ON p.id = s.project_id
       JOIN fs_users u ON u.id = p.user_id
       WHERE s.project_id = $1 AND u.data->>'email' = $2
       ORDER BY s.created_at DESC
       LIMIT 50`,
      [projectId, session.user.email]
    );

    return NextResponse.json({ sessions });
  } catch (err) {
    console.error("[agent/sessions GET]", err);
    return NextResponse.json({ error: "Failed to list sessions" }, { status: 500 });
  }
}