/**
 * @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); `GET /storage` how much disk each user's home takes
 * (server/lib/user-storage.js — measured in a worker, `?refresh=1` re-measures).
 *
 * `GET /tmux` (S3) is each member's own tmux server — its version beside the
 * installed one, its sessions, whether an agent of theirs works — and an
 * admin restarts one (`POST /:id/tmux-restart`) or every idle outdated one
 * (`POST /tmux-restart-idle`), with their password again and audited
 * (server/lib/member-tmux.js); a restart ends that member's panes.
 *
 * `GET /:id` is one account with the workspaces it owns, for the Edit user form;
 * `GET /:id/avatar` its picture (server/lib/avatars.js), for the sidebar's
 * owner groups — staff only like the rest of `/users`.
 *
 * The Users page's account changes — `POST /` (create), `PATCH /:id` (the Edit
 * user form: display name, email, role, disabled, a new password, workspaces
 * given and taken back, sign out everywhere — every field validated before any
 * is applied), `POST /:id/password` (reset) and `POST /:id/workspaces` (give a
 * workspace) — are an admin's only (`/users` is in ADMIN_WRITE_PREFIXES), each
 * needs the admin's own password again (`currentPassword`, `confirmPassword`),
 * an admin never demotes or disables themselves (ESELF), every change is
 * audited, and in local mode — no login to check — they all refuse. A
 * password an admin gives another account (create, reset) may be anything
 * non-empty and makes that account pick its own at its next login
 * (`must_change_password`); an admin's own new password must pass every
 * rule, like Settings → Account's (`validateOwnPassword`, EWEAKPASSWORD).
 * @author Nguyễn Ngọc Trí Vĩ <vinnt@smartgift.vn>
 */

const { Router } = require("express");
const { db, stmts } = require("../db");
const auth = require("../lib/auth");
const { listUsers } = auth;
const { listAudit, recordAccountChange } = 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",
  "long_input_tokens",
  "long_output_tokens",
  "long_cache_read_tokens",
  "long_cache_write_tokens",
  "long_cache_write_1h_tokens",
];

// Which account each session belongs to — through its workspace, or a
// dashboard run on one (server/lib/scope.js's sessionWhere, for every user at once).
const OWNED_SESSIONS = `
  SELECT s.id AS session_id, l.owner_id AS uid
    FROM sessions s JOIN lanes l ON l.id = s.lane_id
   WHERE l.owner_id IS NOT NULL
  UNION
  SELECT s.id, l.owner_id
    FROM dashboard_runs r JOIN lanes l ON l.id = r.lane_id JOIN sessions s ON s.id = r.session_id
   WHERE l.owner_id IS NOT NULL`;

/** Map(user id → {cost, tokens}) every account's sessions spent since `sinceHour` (UTC `YYYY-MM-DDTHH`). */
function usageSince(sinceHour, rules) {
  const { calculateCost } = require("./pricing");
  const rows = db
    .prepare(
      `WITH owned AS (${OWNED_SESSIONS})
       SELECT o.uid, 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 owned o ON o.session_id = h.session_id
        WHERE h.hour >= ?
        GROUP BY o.uid, h.model, h.speed, h.inference_geo, h.service_tier`
    )
    .all(sinceHour);
  const byUser = new Map();
  for (const r of rows) {
    if (!byUser.has(r.uid)) byUser.set(r.uid, []);
    byUser.get(r.uid).push(r);
  }
  const out = new Map();
  for (const [uid, list] of byUser) {
    const tokens = list.reduce(
      (n, r) => n + r.input_tokens + r.output_tokens + r.cache_read_tokens + r.cache_write_tokens,
      0
    );
    out.set(uid, { cost: calculateCost(list, rules).total_cost, tokens });
  }
  return out;
}

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

/** Map(key → n) from rows of `{k, n}`. */
const counts = (rows) => new Map(rows.map((r) => [r.k, r.n]));

router.get("/", (_req, res) => {
  const rules = stmts.listPricing.all();
  // A fixed number of grouped queries, however many accounts there are.
  const logins = auth.allLoginStats();
  const workspaces = counts(
    db.prepare("SELECT owner_id AS k, COUNT(*) AS n FROM lanes GROUP BY owner_id").all()
  );
  const sessions = counts(
    db.prepare(`SELECT uid AS k, COUNT(*) AS n FROM (${OWNED_SESSIONS}) GROUP BY uid`).all()
  );
  const last7d = usageSince(hourAgo(7), rules);
  const last30d = usageSince(hourAgo(30), rules);
  const none = { cost: 0, tokens: 0 };
  const users = listUsers().map((u) => ({
    ...u,
    ...(logins.get(u.id) || { logins: 0, lastLoginAt: null }),
    workspaces: workspaces.get(u.id) || 0,
    sessions: sessions.get(u.id) || 0,
    last7d: last7d.get(u.id) || none,
    last30d: last30d.get(u.id) || none,
  }));
  res.json({ users });
});

router.get("/storage", (req, res) => {
  const { storageFor } = require("../lib/user-storage");
  res.json(storageFor(listUsers(), { refresh: req.query.refresh === "1" }));
});

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

/** S3: each member's tmux server — its version beside the installed one (member-tmux.js). */
router.get("/tmux", (_req, res) => {
  res.json(require("../lib/member-tmux").overview(listUsers()));
});

const STATUS = {
  EBADUSER: 400,
  EBADEMAIL: 400,
  ENOTOWNED: 409,
  EBADPASSWORD: 400,
  EWEAKPASSWORD: 400,
  EBADROLE: 400,
  EBADFIELD: 400,
  EREAUTH: 403,
  ELOCALMODE: 403,
  ENOUSER: 404,
  ENOLANE: 404,
  EEXISTS: 409,
  ESELF: 409,
  EOWNERFOLDER: 409, // S3: a workspace in one member's home, assigned to another
  ELASTADMIN: 409,
  ETOOMANY: 429,
  // S3: the Linux account could not be created/locked (the helper said why).
  EPROVISION: 502,
  ENOS3: 409,
  // A member's tmux server that would not stop: root has to kill it.
  ETMUXSTUCK: 409,
};

/**
 * One account change: server mode only, the admin's password confirmed, the
 * change made, then audited. `fn(target)` returns the audit text.
 */
function accountChange(handler) {
  return async (req, res) => {
    try {
      if (!auth.isServerMode() || !req.user) {
        throw Object.assign(new Error("accounts are managed in server mode only"), {
          code: "ELOCALMODE",
        });
      }
      const body = req.body && typeof req.body === "object" ? req.body : {};
      await auth.confirmPassword(req.user, body.currentPassword);
      const out = await handler(req, body);
      recordAccountChange(req.user.id, out.user.id, req.method, out.action);
      res.status(out.status || 200).json({ user: out.user });
    } catch (err) {
      const status = STATUS[err.code];
      if (!status) return res.status(500).json({ error: { message: err.message } });
      res.status(status).json({
        error: { code: err.code, message: err.message, ...(err.rules && { rules: err.rules }) },
      });
    }
  };
}

/** The account `:id` names (404 ENOUSER otherwise). */
function target(req) {
  const u = db.prepare("SELECT * FROM users WHERE id = ?").get(Number(req.params.id));
  if (!u) throw Object.assign(new Error("no such user"), { code: "ENOUSER" });
  return u;
}

router.get("/:id", (req, res) => {
  const u = db.prepare("SELECT * FROM users WHERE id = ?").get(Number(req.params.id));
  if (!u) return res.status(404).json({ error: { code: "ENOUSER", message: "no such user" } });
  res.json({
    user: { ...auth.publicUser(u), ...auth.loginStats(u.id) },
    workspaces: auth.ownedWorkspaces(u.id),
  });
});

router.get("/:id/avatar", (req, res) => {
  const id = Number(req.params.id);
  const file = Number.isSafeInteger(id) && id > 0 ? require("../lib/avatars").avatarFile(id) : null;
  if (!file) return res.status(404).json({ error: { code: "ENOAVATAR", message: "no avatar" } });
  res.set("Content-Type", file.type);
  res.set("X-Content-Type-Options", "nosniff");
  res.set("Content-Security-Policy", "sandbox; default-src 'none'");
  // Versioned by the client with the owner's `avatarAt`.
  res.set("Cache-Control", "private, max-age=86400");
  res.sendFile(file.path);
});

/** A list of workspace ids from the body, or [] when absent. */
function laneIds(value, field) {
  if (value === undefined) return [];
  if (!Array.isArray(value) || value.some((v) => !Number.isInteger(v) || v <= 0)) {
    throw Object.assign(new Error(`${field}: a list of workspace ids`), { code: "EBADFIELD" });
  }
  return [...new Set(value)];
}

router.post(
  "/",
  accountChange(async (_req, body) => {
    const role = body.role === undefined ? "developer" : body.role;
    // The admin's password is a starting one: the user picks their own first.
    const user = await auth.createUser(body.username, body.password, role, { mustChange: true });
    return { status: 201, user, action: `create ${user.username} (${user.role})` };
  })
);

router.patch(
  "/:id",
  accountChange(async (req, body) => {
    const u = target(req);
    const self = u.id === req.user.id;
    const ESELF = (msg) => Object.assign(new Error(msg), { code: "ESELF" });

    // 1. Validate everything — nothing is written until all of it passes.
    const profile = auth.validateProfile(body);
    const roleChange = body.role !== undefined && body.role !== u.role;
    if (roleChange) {
      if (self) throw ESELF("you cannot change your own role");
      if (!auth.ROLES.includes(body.role)) {
        throw Object.assign(new Error(`role: one of ${auth.ROLES.join(", ")}`), {
          code: "EBADROLE",
        });
      }
    }
    if (body.disabled !== undefined) {
      if (typeof body.disabled !== "boolean") {
        throw Object.assign(new Error("disabled: true or false"), { code: "EBADFIELD" });
      }
      if (self && body.disabled) throw ESELF("you cannot disable yourself");
    }
    const disabledChange = body.disabled !== undefined && body.disabled !== Boolean(u.disabled);
    if (body.password !== undefined) {
      // Your own password: every rule. Someone else's: a starting one they replace.
      if (self) {
        auth.validateOwnPassword(body.password, u.username);
        await auth.assertNotCurrent(u.id, body.password);
      } else auth.validatePassword(body.password);
    }
    if (body.signOut !== undefined && body.signOut !== true) {
      throw Object.assign(new Error("signOut: true"), { code: "EBADFIELD" });
    }
    const add = laneIds(body.addWorkspaces, "addWorkspaces");
    const remove = laneIds(body.removeWorkspaces, "removeWorkspaces");
    const runAs = require("../lib/run-as");
    for (const id of [...add, ...remove]) {
      const lane = db.prepare("SELECT owner_id, cwd FROM lanes WHERE id = ?").get(id);
      if (!lane) throw Object.assign(new Error(`no workspace ${id}`), { code: "ENOLANE" });
      if (remove.includes(id) && lane.owner_id !== u.id) {
        throw Object.assign(new Error(`workspace ${id} is not ${u.username}'s`), {
          code: "ENOTOWNED",
        });
      }
      // S3: a workspace in a member's home is theirs alone (EOWNERFOLDER).
      if (add.includes(id)) runAs.assertOwnerFits(lane.cwd, u.id);
    }

    // 2. Apply. Disable last: it may stop panes and lock a Linux account
    //    (EPROVISION), and the admin should learn that after the rest held.
    const done = [];
    if (Object.keys(profile).length) {
      auth.setProfile(u.id, profile);
      if ("display_name" in profile) done.push("display name");
      if ("email" in profile) done.push("email");
    }
    if (roleChange) {
      auth.setRole(u.username, body.role);
      done.push(`role ${body.role}`);
    }
    for (const id of add) auth.assignWorkspace(id, u.username);
    for (const id of remove) auth.unassignWorkspace(id, u.username);
    if (add.length) done.push(`workspace ${add.join(", ")}`);
    if (remove.length) done.push(`removed workspace ${remove.join(", ")}`);
    // An admin changing their own password or signing themselves out keeps
    // the login they are doing it from.
    const keepToken = self ? auth.cookieToken(req) : undefined;
    if (body.password !== undefined) {
      await auth.setPassword(u.username, body.password, { keepToken, mustChange: !self });
      done.push("password reset");
    }
    if (body.signOut) {
      auth.endSessions(u.id, keepToken);
      done.push("signed out everywhere");
    }
    if (disabledChange) {
      auth.setDisabled(u.username, body.disabled);
      done.push(body.disabled ? "disable" : "enable");
    }
    return {
      user: { ...auth.publicUser(target(req)), ...auth.loginStats(u.id) },
      action: `${u.username}: ${done.join(", ") || "no change"}`,
    };
  })
);

/**
 * Delete a user for good (auth.deleteUser): their logins, panes, workspaces'
 * records and — under S3 — their Linux account and whole home. Never
 * yourself (ESELF) or the last admin (ELASTADMIN); the admin's password
 * again, like every account change, and written to the audit log.
 */
router.delete(
  "/:id",
  accountChange(async (req) => {
    const u = target(req);
    if (u.id === req.user.id) {
      throw Object.assign(new Error("you cannot delete yourself"), { code: "ESELF" });
    }
    const gone = auth.deleteUser(u.username);
    return {
      user: auth.publicUser(u),
      action: `delete ${u.username} (${gone.workspaces} workspace(s), home removed)`,
    };
  })
);

/**
 * Restart one member's tmux server (every pane of theirs ends, so the next
 * start runs the installed tmux) — the admin's password again, audited.
 */
router.post(
  "/:id/tmux-restart",
  accountChange(async (req) => {
    const u = target(req);
    const r = require("../lib/member-tmux").restart(u);
    return {
      user: auth.publicUser(u),
      action: r.restarted
        ? `${u.username}: tmux restarted (was ${r.before.version || "?"}, ${r.before.sessions ?? "?"} session(s))`
        : `${u.username}: tmux restart — no server was running`,
    };
  })
);

/**
 * Restart the tmux server of every member running an older tmux than the
 * installed one while no agent of theirs works. One password, one audit
 * entry per member restarted.
 */
router.post("/tmux-restart-idle", async (req, res) => {
  try {
    if (!auth.isServerMode() || !req.user) {
      throw Object.assign(new Error("accounts are managed in server mode only"), {
        code: "ELOCALMODE",
      });
    }
    const body = req.body && typeof req.body === "object" ? req.body : {};
    await auth.confirmPassword(req.user, body.currentPassword);
    const mt = require("../lib/member-tmux");
    const all = db.prepare("SELECT * FROM users ORDER BY id").all();
    const rows = mt.overview(all.map(auth.publicUser)).users;
    const restarted = [];
    const skipped = [];
    const failed = [];
    for (const row of rows) {
      if (!row.outdated) continue;
      if (row.busy > 0) {
        skipped.push(row.username);
        continue;
      }
      const u = all.find((x) => x.id === row.id);
      try {
        const r = mt.restart(u);
        if (!r.restarted) continue;
        restarted.push(row.username);
        recordAccountChange(
          req.user.id,
          u.id,
          "POST",
          `${u.username}: tmux restarted (idle, was ${row.version})`
        );
      } catch (e) {
        failed.push({ username: row.username, message: e.message });
      }
    }
    res.json({ restarted, skipped, failed });
  } catch (err) {
    const status = STATUS[err.code];
    if (!status) return res.status(500).json({ error: { message: err.message } });
    res.status(status).json({ error: { code: err.code, message: err.message } });
  }
});

router.post(
  "/:id/password",
  accountChange(async (req, body) => {
    const u = target(req);
    const self = u.id === req.user.id;
    if (self) {
      auth.validateOwnPassword(body.password, u.username);
      await auth.assertNotCurrent(u.id, body.password);
    }
    await auth.setPassword(u.username, body.password, {
      keepToken: self ? auth.cookieToken(req) : undefined,
      mustChange: !self,
    });
    return { user: auth.publicUser(u), action: `${u.username}: password reset` };
  })
);

router.post(
  "/:id/workspaces",
  accountChange(async (req, body) => {
    const u = target(req);
    auth.assignWorkspace(body.laneId, u.username);
    return { user: auth.publicUser(u), action: `${u.username}: workspace ${Number(body.laneId)}` };
  })
);

module.exports = router;