// Credential references (note section 2, addendum A section 7). A
// reference names where a token lives, never the token. The checks here use
// lstat and realpath only; nothing in this package opens a token file.

import { lstatSync, realpathSync } from "node:fs";
import { isAbsolute, join, normalize, relative, sep } from "node:path";
import { refuse } from "./errors.mjs";
import { credentialKind, isHostKind } from "./vocabulary.mjs";
import { requireObject, rejectUnknownKeys, requireDate } from "./util.mjs";

import { pluginName } from "../../plugins/src/organization.mjs";

const ENV_NAME = /^[A-Z][A-Z0-9_]{0,63}$/;
export const DATE_KEY = Object.freeze({ gitea: "rotateBy", vikunja: "expires" });
const WARN_DAYS = 7;
const DAY_MS = 24 * 60 * 60 * 1000;

// Shape check for one reference. Returns a frozen { service, file | env,
// rotateBy | expires }. Row 199 (#1697, design D1 and D2): `store` is the
// file at <configDir>/secrets/agents/<business>/<agent>/<service>, derived
// here and never written, so an entry can't name another agent's file. A
// reference with no agent (the tracker's sync bot) passes store = null and
// can't use the form. A `file` reference into the agents' store must be the
// agent's own path (`credential-not-yours`).
export function parseCredentialRef(ref, service, where, { store = null } = {}) {
  if (!credentialKind(service) && !pluginName(service)) refuse(`${where}: unknown credential service ${JSON.stringify(service)}`);
  requireObject(ref, where);
  // Row 210 (#1707, design D1): an ssh key doesn't expire, so host.<id> takes rotateBy as gitea does.
  const dateKey = isHostKind(service) ? "rotateBy" : (DATE_KEY[service] ?? "rotateBy");
  rejectUnknownKeys(ref, ["file", "env", "store", dateKey], where);
  const hasFile = ref.file !== undefined;
  const hasEnv = ref.env !== undefined;
  const hasStore = ref.store !== undefined;
  if (Number(hasFile) + Number(hasEnv) + Number(hasStore) !== 1) refuse(`${where} must name exactly one of "file", "env" or "store"`);
  const out = { service };
  if (hasStore) {
    if (ref.store !== true) refuse(`${where}.store must be true`);
    if (!store) refuse(`${where}: a "store" reference needs an agent`);
    out.store = true;
    out.file = storePath(store, service);
  } else if (hasFile) {
    if (typeof ref.file !== "string" || !isAbsolute(ref.file) || normalize(ref.file) !== ref.file || ref.file.includes("\0")) {
      refuse(`${where}.file must be a normalized absolute path`);
    }
    out.file = ref.file;
    if (store && inside(join(store.configDir, "secrets", "agents"), ref.file) && ref.file !== storePath(store, service)) {
      refuse(`${where}.file credential-not-yours: the file is in the agents' store but not this agent's path`);
    }
  } else {
    if (typeof ref.env !== "string" || !ENV_NAME.test(ref.env)) refuse(`${where}.env must match ${ENV_NAME}`);
    out.env = ref.env;
  }
  if (ref[dateKey] === undefined) refuse(`${where} needs "${dateKey}" (YYYY-MM-DD)`);
  out[dateKey] = requireDate(ref[dateKey], `${where}.${dateKey}`);
  return Object.freeze(out);
}

// The store path for one agent and service (design D1).
export function storePath({ configDir, business, agent }, service) {
  return join(configDir, "secrets", "agents", business, agent, service);
}

function inside(root, path) {
  const rel = relative(root, path);
  return rel === "" || (!rel.startsWith(`..${sep}`) && rel !== ".." && !isAbsolute(rel));
}

// Check a parsed reference against the filesystem and the calendar.
// Returns { problems: [...], warnings: [...] }; a caller that finds any
// problem refuses. `forbiddenRoots` are directories a token file must not
// sit in (the repository, dataRoot): each a path, or { path, label } so a
// problem can name it. `where` is the reference's field (for example
// roles.coder.credentials.gitea). `now` is a Date.
// A problem or warning names the reference by its field, its service and its
// kind, and an env reference by its checked variable name. It never quotes the
// token file's path or a root's path (#1873).
export function checkCredentialRef(ref, { forbiddenRoots = [], now = new Date(), env = process.env, uid = process.getuid(), where = null } = {}) {
  const problems = [];
  const warnings = [];
  const label = `${where ?? ref.service} ${ref.store ? "store file" : ref.file ? "file" : `env ${ref.env}`}`;
  let notIssued = false;
  if (ref.file) {
    let stat = null;
    try {
      stat = lstatSync(ref.file);
    } catch (e) {
      // Row 199 (design D3a): a store reference with no file is an agent not issued yet.
      notIssued = Boolean(ref.store) && e.code === "ENOENT";
      if (notIssued) warnings.push(`${label}: not issued`);
      else problems.push(`${label}: not found`);
    }
    if (stat) {
      if (stat.isSymbolicLink() || !stat.isFile()) problems.push(`${label}: must be a regular file, not a symbolic link`);
      else {
        if (stat.uid !== uid) problems.push(`${label}: owned by uid ${stat.uid}, not ${uid}`);
        if ((stat.mode & 0o077) !== 0) problems.push(`${label}: mode ${(stat.mode & 0o777).toString(8)} gives group or other access; use 600`);
        if (stat.size === 0) problems.push(`${label}: empty`);
        let real = ref.file;
        try {
          real = realpathSync(ref.file);
        } catch {
          problems.push(`${label}: path can't be resolved`);
        }
        for (const entry of forbiddenRoots) {
          const root = typeof entry === "string" ? entry : entry.path;
          const name = typeof entry === "string" ? "a forbidden root" : entry.label;
          let realRoot = root;
          try {
            realRoot = realpathSync(root);
          } catch {
            // A root that doesn't exist yet can't contain the file.
          }
          if (inside(realRoot, real)) problems.push(`${label}: inside ${name}; token files live outside the repository and dataRoot`);
        }
      }
    }
  } else if (env[ref.env] === undefined || env[ref.env] === "") {
    warnings.push(`${label}: not set in this environment; the launcher must provide it`);
  }
  // Row 194 (brief item 7, sage-1605 pick a): a human create writes the create day as the date,
  // and issue writes the real one. Until then the date describes no token, so a store reference
  // with no file skips both date checks. Every other reference keeps them.
  if (notIssued) return { problems, warnings };
  const days = (dateText) => Math.floor((Date.parse(`${dateText}T00:00:00Z`) - now.getTime()) / DAY_MS);
  if (ref.expires) {
    const left = days(ref.expires);
    if (Date.parse(`${ref.expires}T00:00:00Z`) <= now.getTime()) problems.push(`${label}: expired on ${ref.expires}`);
    else if (left < WARN_DAYS) warnings.push(`${label}: expires on ${ref.expires}`);
  }
  if (ref.rotateBy && Date.parse(`${ref.rotateBy}T00:00:00Z`) <= now.getTime()) {
    warnings.push(`${label}: rotation was due on ${ref.rotateBy}`);
  }
  return { problems, warnings };
}