/* web/js/state.js — small app-wide state: run mode, theme, and the
 * transcript accumulated so far. No framework, just a plain object plus a
 * handful of pub/sub-free helper functions; main.js owns when to re-render. */

"use strict";

const STORAGE_THEME_KEY = "lsa-web-theme";
const STORAGE_BASE_KEY = "lsa-web-base";
const STORAGE_SESSION_KEY = "lsa-web-session-id";
const STORAGE_INTERPRET_KEY = "lsa-web-interpret";
const STORAGE_LANG_KEY = "lsa-web-lang";

export const state = {
  // "live" is the default. A deployment is live and the analysts opening
  // this page expect real answers; defaulting to "simulated" would mean
  // synthetic, made-up numbers render in the exact same UI as real ones
  // — clearly labelled, but still the wrong DEFAULT once the system is
  // actually serving people. Simulated mode stays fully available (it is
  // genuinely used for demos and training — see web/README.md's
  // "Modes"); only the default changes. See resolveBootMode below for
  // how `?live=0` / `?live=1` override this — the only override left;
  // run mode is a deploy/debug concern now, not a topbar control an
  // analyst could mis-click into showing synthetic data as real.
  // Consequence to hold honestly: on a first load against
  // an unreachable backend, an analyst now sees an error (from
  // refreshHealth in main.js) instead of a working simulated demo — see
  // that error's own wording for why that is the right trade.
  mode: "live", // "simulated" | "live"
  // Placeholder only -- every real page boot (web/js/main.js,
  // web/admin/main.js) overwrites this immediately via
  // resolveDefaultBaseUrl (config.js's DEFAULT_BASE_URL/DEFAULT_API_PORT)
  // before loadPersisted() even runs. Kept non-empty here only so a
  // module that imports state.js without running either boot sequence
  // (a stray test, say) still gets a syntactically valid URL rather than
  // an empty string.
  baseUrl: "http://localhost:8000",
  theme: "system", // "system" | "light" | "dark"
  lang: "fa", // "fa" | "en" — chrome only; questions may be either
  sessionId: null,
  sessions: [], // SessionSummary[] — the conversation-list sidebar's index
  turns: [], // Turn[] rendered so far, in order
  memory: null, // {entries, rememberable} | null — the memory panel's last fetch
  // Whether each turn asks for a plain-language summary. Off by default,
  // matching the API: an interpretation sends up to twenty rows of real
  // result data to the model, and defaulting that on would be deciding
  // for the analyst rather than asking them.
  interpret: false,
  busy: false,
  nextScriptedIndex: 0, // pointer into SCENARIO.turns for the "sample" flow
};

export function loadPersisted() {
  try {
    const t = localStorage.getItem(STORAGE_THEME_KEY);
    if (t === "light" || t === "dark" || t === "system") state.theme = t;
  } catch { /* localStorage unavailable (private mode, etc.) — keep default */ }
  try {
    const b = localStorage.getItem(STORAGE_BASE_KEY);
    if (b) {
      // A value saved before normalizeBaseUrl existed (or saved by a
      // build that had a bug, like the real "172.16.101.42:8076" no
      // scheme/trailing-path incident this normalisation exists for)
      // must not go on shadowing the deploy default forever just
      // because it once made it into localStorage. Repair it in place
      // when it is fixable (e.g. missing scheme); when it is not
      // parseable/valid at all, drop it instead of loading a value that
      // would only fail every request — the deploy-time default (already
      // in state.baseUrl at this point in the boot sequence) stands.
      const result = normalizeBaseUrl(b);
      if (result.ok) {
        state.baseUrl = result.url;
        if (result.url !== b) {
          try { localStorage.setItem(STORAGE_BASE_KEY, result.url); } catch { /* ignore */ }
        }
      } else {
        try { localStorage.removeItem(STORAGE_BASE_KEY); } catch { /* ignore */ }
      }
    }
  } catch { /* ignore */ }
  try {
    const s = localStorage.getItem(STORAGE_SESSION_KEY);
    if (s) state.sessionId = s;
  } catch { /* ignore — reload just won't return the analyst to the same conversation */ }
  try {
    state.interpret = localStorage.getItem(STORAGE_INTERPRET_KEY) === "1";
  } catch { /* ignore — the toggle just won't survive a reload */ }
  try {
    const lang = localStorage.getItem(STORAGE_LANG_KEY);
    if (lang === "fa" || lang === "en") state.lang = lang;
  } catch { /* ignore — default fa */ }
}

/** Remembers the analyst's interpretation choice for this browser. */
export function persistInterpret(on) {
  state.interpret = !!on;
  try {
    if (state.interpret) localStorage.setItem(STORAGE_INTERPRET_KEY, "1");
    else localStorage.removeItem(STORAGE_INTERPRET_KEY);
  } catch { /* ignore — it just won't survive a reload */ }
}

/** Remembers which conversation the analyst was on, so a reload returns
 * them to it (see resolveActiveSessionId, which reconciles this stored id
 * against the real index once it's fetched — the id might be stale). */
export function persistSessionId(sessionId) {
  state.sessionId = sessionId;
  try {
    if (sessionId) localStorage.setItem(STORAGE_SESSION_KEY, sessionId);
    else localStorage.removeItem(STORAGE_SESSION_KEY);
  } catch { /* ignore — the choice just won't survive a reload */ }
}

/** Picks which session should be active once the real index is known.
 * Pure, total, no localStorage access (loadPersisted already read the
 * raw stored id; this just reconciles it against the index):
 *   - an empty index -> null (first-run: nothing to select yet).
 *   - a stored id still present in the index -> kept as-is.
 *   - a stored id that is stale, missing, or was never set -> the most
 *     recently active session in the index, never a thrown error and
 *     never an arbitrary (e.g. array-order) pick. */
export function resolveActiveSessionId(storedId, sessions) {
  if (!sessions || sessions.length === 0) return null;
  if (storedId && sessions.some((s) => s.session_id === storedId)) return storedId;
  const newest = sessions.slice().sort(
    (a, b) => new Date(b.last_active_at).getTime() - new Date(a.last_active_at).getTime(),
  )[0];
  return newest.session_id;
}

/** Resolves the effective run mode for THIS page load from the `?live=`
 * URL param, falling back to *defaultMode* (state.mode's own initial
 * value, "live" — see its comment above) when the param is absent or
 * unrecognized. Pure, total, no DOM/localStorage access, so the exact
 * precedence rule is unit-testable without standing up the whole page:
 *   - `?live=1` -> "live" (explicit opt-in — e.g. a bookmarked/shared link)
 *   - `?live=0` -> "simulated" (explicit opt-out — demos, training, CI)
 *   - anything else (param absent, or an unrecognized value) -> defaultMode
 * Keeping this a pure function (rather than the inline if/if it used to
 * be in main.js's boot) is what lets the DEFAULT itself change in exactly
 * one place (state.mode's initializer) without this precedence rule
 * needing to change, or be re-verified, along with it. */
export function resolveBootMode(searchParams, defaultMode) {
  const live = searchParams.get("live");
  if (live === "1") return "live";
  if (live === "0") return "simulated";
  return defaultMode;
}

/** Resolves the effective backend base URL for THIS page load. `?base=`
 * is the highest-precedence override (an operator pointing this one load
 * somewhere else for debugging) and always wins when present; otherwise
 * *currentBaseUrl* stands unchanged — by the time main.js calls this,
 * loadPersisted() has already folded in a localStorage override (if any)
 * on top of web/js/config.js's deploy-time DEFAULT_BASE_URL, so "leave it
 * alone" here already means "the persisted value, or the deploy default".
 * Pure, total, no DOM access. */
export function resolveBootBaseUrl(searchParams, currentBaseUrl) {
  const base = searchParams.get("base");
  return base ? base : currentBaseUrl;
}

/** Derives the effective deploy-time DEFAULT backend base URL from
 * web/js/config.js's two constants and THIS page's own location, so both
 * web/ and web/admin/ resolve the same default the same way without
 * either one hardcoding a host.
 *
 * *defaultBaseUrl* (config.js's DEFAULT_BASE_URL) wins whenever it is a
 * non-empty string, unchanged — this is the existing, documented "one
 * file a deployment edits" path, kept exactly as it already worked.
 * Only when it is empty does this derive an address from *pageOrigin*
 * (an object with `protocol`/`hostname`, e.g. `window.location` itself,
 * or a plain object in a test) and *defaultApiPort* (config.js's
 * DEFAULT_API_PORT): `<page protocol>//<page hostname>:<port>`. This is
 * what lets a deployment move the API+UI pair to a new host with no JS
 * edit at all — the API is assumed reachable on the same hostname the
 * page itself was loaded from, just on its own port.
 *
 * Pure, total, no DOM access beyond reading the two fields off
 * *pageOrigin* that are passed in explicitly — unit-testable without a
 * real `window.location`. */
export function resolveDefaultBaseUrl(defaultBaseUrl, defaultApiPort, pageOrigin) {
  const trimmed = (defaultBaseUrl || "").trim();
  if (trimmed) return trimmed;
  return `${pageOrigin.protocol}//${pageOrigin.hostname}:${defaultApiPort}`;
}

/** Closed set of reasons normalizeBaseUrl can reject a value — each
 * page renders its OWN message (in its own language) for each reason
 * rather than this shared module owning any UI copy; see
 * web/js/main.js's / web/admin/main.js's own mapping. */
export const BASE_URL_INVALID_EMPTY = "empty";
export const BASE_URL_INVALID_UNPARSEABLE = "unparseable";
export const BASE_URL_INVALID_SCHEME = "scheme";

/** Normalises and validates a typed or saved API base-address string —
 * an admin top-bar entry, a `?base=` query param, or a value already
 * sitting in localStorage from a previous, possibly-bad save.
 *
 * A real deployment typed "172.16.101.42:8076" (no scheme) into the
 * admin top bar; `fetch` then treated it as a RELATIVE path, and every
 * request went to `GET /admin/172.16.101.42:8076/admin/...` on the
 * static file server instead of the API. This exists so that never
 * happens silently again:
 *   1. trim whitespace;
 *   2. if there is no `scheme://` prefix, prepend `http://` (the exact
 *      repair the incident above needed);
 *   3. parse with `new URL()` — a value that still does not parse (spaces,
 *      garbage, ...) is rejected, not silently used as a relative path;
 *   4. reject anything whose scheme is not `http`/`https` (e.g.
 *      `javascript:`, `file:`);
 *   5. on success, keep only the origin — `protocol//host` — discarding
 *      any path, query, or trailing slash, so `http://host:port/some/path`
 *      and `http://host:port/` both normalise to `http://host:port`.
 *
 * A second, narrower repair lives here too: a value that does NOT start
 * with a scheme but has one embedded further in ("/http://host:port" —
 * an accidental leading slash pasted in front of an otherwise-correct
 * address) is deliberately REJECTED rather than guessed at. Blindly
 * prepending "http://" to that one (as step 2 does for the ordinary
 * no-scheme case) parses "successfully" into a nonsense origin
 * (`new URL("http:///http://host:port")` resolves the second "http" as
 * the HOSTNAME, silently) — a wrong answer that never surfaces as an
 * error. An address that already contains "://" somewhere is only safe
 * to accept when that occurrence is the leading scheme; anywhere else,
 * this rejects it with a clear reason instead of risking a silent
 * mis-parse toward the wrong host.
 *
 * Returns `{ok: true, url}` or `{ok: false, reason}` (one of the
 * `BASE_URL_INVALID_*` constants above) — never throws. Pure, total, no
 * DOM/localStorage access. */
export function normalizeBaseUrl(raw) {
  const trimmed = (raw || "").trim();
  if (!trimmed) return { ok: false, reason: BASE_URL_INVALID_EMPTY };
  const hasSchemePrefix = /^[a-zA-Z][a-zA-Z0-9+.-]*:\/\//.test(trimmed);
  const hasSchemeElsewhere = !hasSchemePrefix && /:\/\//.test(trimmed);
  if (hasSchemeElsewhere) return { ok: false, reason: BASE_URL_INVALID_UNPARSEABLE };
  const candidate = hasSchemePrefix ? trimmed : `http://${trimmed}`;
  let parsed;
  try {
    parsed = new URL(candidate);
  } catch {
    return { ok: false, reason: BASE_URL_INVALID_UNPARSEABLE };
  }
  if (parsed.protocol !== "http:" && parsed.protocol !== "https:") {
    return { ok: false, reason: BASE_URL_INVALID_SCHEME };
  }
  return { ok: true, url: parsed.origin };
}

export function persistTheme(theme) {
  state.theme = theme;
  try {
    localStorage.setItem(STORAGE_THEME_KEY, theme);
  } catch { /* ignore — theme just won't survive a reload */ }
}

export function persistBaseUrl(url) {
  state.baseUrl = url;
  try {
    localStorage.setItem(STORAGE_BASE_KEY, url);
  } catch { /* ignore */ }
}

export function applyTheme() {
  const root = document.documentElement;
  if (state.theme === "system") root.removeAttribute("data-theme");
  else root.setAttribute("data-theme", state.theme);
}

export function addTurn(turn) {
  state.turns.push(turn);
  return turn;
}

export function findTurn(turnId) {
  return state.turns.find((t) => t.turn_id === turnId) || null;
}

export function resetTranscript() {
  state.turns = [];
  state.nextScriptedIndex = 0;
}