/**
 * @file users.js
 * @description `/api/users` — server mode's per-user view for an admin or
 * analyst (members are refused by STAFF_ONLY_PREFIXES in server/lib/auth.js):
 * `GET /` lists every account with its workspaces, sessions and $ spent in the
 * last 7 and 30 days (from `token_usage_hourly`, sessions owned through their
 * workspace — server/lib/scope.js); `GET /audit` the newest audit entries
 * (server/lib/audit.js). Read-only: accounts are managed from the host's shell.
 * @author Nguyễn Ngọc Trí Vĩ <vinnt@smartgift.vn>
 */

const { Router } = require("express");
const { db, stmts } = require("../db");
const { listUsers } = require("../lib/auth");
const { sessionWhere } = require("../lib/scope");
const { listAudit } = require("../lib/audit");

const router = Router();

const USAGE_COLS = [
  "input_tokens",
  "output_tokens",
  "cache_read_tokens",
  "cache_write_tokens",
  "cache_write_1h_tokens",
  "web_search_requests",
  "web_fetch_requests",
  "code_execution_requests",
];

/** $ and tokens a member's sessions spent since `sinceHour` (UTC `YYYY-MM-DDTHH`). */
function usageSince(userId, sinceHour, rules) {
  const { calculateCost } = require("./pricing");
  const w = sessionWhere({ user: { id: userId, role: "member" } }, "s.id", "s.lane_id");
  const rows = db
    .prepare(
      `SELECT h.model, h.speed, h.inference_geo, h.service_tier,
              ${USAGE_COLS.map((c) => `SUM(h.${c}) AS ${c}`).join(", ")}
         FROM token_usage_hourly h JOIN sessions s ON s.id = h.session_id
        WHERE h.hour >= ? AND ${w.where}
        GROUP BY h.model, h.speed, h.inference_geo, h.service_tier`
    )
    .all(sinceHour, ...w.params);
  const tokens = rows.reduce(
    (n, r) => n + r.input_tokens + r.output_tokens + r.cache_read_tokens + r.cache_write_tokens,
    0
  );
  return { cost: rows.length ? calculateCost(rows, rules).total_cost : 0, tokens };
}

const hourAgo = (days) => new Date(Date.now() - days * 864e5).toISOString().slice(0, 13);

router.get("/", (_req, res) => {
  const rules = stmts.listPricing.all();
  const users = listUsers().map((u) => {
    const w = sessionWhere({ user: { id: u.id, role: "member" } });
    return {
      ...u,
      workspaces: db.prepare("SELECT COUNT(*) AS n FROM lanes WHERE owner_id = ?").get(u.id).n,
      sessions: db.prepare(`SELECT COUNT(*) AS n FROM sessions WHERE ${w.where}`).get(...w.params)
        .n,
      last7d: usageSince(u.id, hourAgo(7), rules),
      last30d: usageSince(u.id, hourAgo(30), rules),
    };
  });
  res.json({ users });
});

router.get("/audit", (req, res) => {
  res.json({ entries: listAudit(req.query.limit) });
});

module.exports = router;