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/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
/**
* Cross-source sessionization for memory generation.
*
* `buildSessions` merges history visits, searches, and chat messages into a
* single timestamped event stream and groups them into sessions by gap and
* maximum session length. A downstream LLM step processes one session at a
* time, so the model sees browsing context and chat context that occurred
* together in time as one bundle.
*
* Source IDs are tracked separately by sources (`history_source_ids` for
* `url_hash` values, `conversation_source_ids` for `convId` values) so a
* revocation hook can match the right kind of ID when the user deletes
* history or a conversation.
*
* This function is pure: it does not read prefs. Callers gate via
* `MemoriesManager.shouldEnableMemoriesFromSchedulers` and pass `[]` for
* any disabled source:
* - both enabled → cross-source sessions
* - history only → history-only sessions
* - chat only → chat-only sessions, time-bucketed by message timestamp
* - neither → caller short-circuits before calling
*
*/
const MS_PER_SEC = 1_000;
const MICROS_PER_MS = 1_000;
const DEFAULT_GAP_SEC = 900;
const DEFAULT_MAX_SESSION_SEC = 7_200;
const KIND_VISIT = "visit";
const KIND_SEARCH = "search";
const KIND_CHAT = "chat";
/**
* Build per-session bundles from history rows and chat messages.
*
* A new session begins when either (a) the gap to the previous event
* exceeds `gapSec`, or (b) the running session length exceeds
* `maxSessionSec`. Visits, searches, and chat messages share the same
* sessionization stream.
*
* @param {Array<object>} [history]
* Output of `getRecentHistory()`. Each row must carry `visitDateMicros`;
* may carry `urlHash`, `source` ("history"|"search"), `url`, `domain`,
* `title`, `frequencyPct`, `domainFrequencyPct`. Rows without a finite
* `visitDateMicros` are skipped.
*
* @param {Array<object>} [chats]
* Output of `getRecentChats()`. Each message must carry a finite
* `createdDate` (epoch ms number or Date) and a non-null `convId`;
* messages missing either are skipped. May carry `role`, `content`,
* `pageUrl`, `freshness_score`.
*
* @param {object} [opts]
* @param {number} [opts.gapSec=900]
* Max allowed gap between consecutive events within one session, seconds.
* @param {number} [opts.maxSessionSec=7200]
* Max total session length, seconds.
*
* @returns {Array<{
* session_id: number,
* session_start_ms: number,
* session_end_ms: number,
* visit_count: number,
* search_count: number,
* chat_count: number,
* total_view_time_ms: number,
* chats: Array<object>,
* history_source_ids: Array<string|number>,
* conversation_source_ids: Array<string>,
* domains: Array<string>,
* titles: Array<string>,
* search_queries: Array<string>,
* }>}
* Sessions in ascending start-time order. `history_source_ids`,
* `conversation_source_ids`, `domains`, `titles`, and `search_queries`
* are deduped. `visit_count` / `search_count` / `chat_count` are raw
* event tallies. `chats` keeps the raw user messages.
*/
export function buildSessions(history = [], chats = [], opts = {}) {
const gapMs = (opts.gapSec ?? DEFAULT_GAP_SEC) * MS_PER_SEC;
const maxSessionMs =
(opts.maxSessionSec ?? DEFAULT_MAX_SESSION_SEC) * MS_PER_SEC;
const events = [];
for (const row of history) {
if (!Number.isFinite(row.visitDateMicros)) {
continue;
}
events.push({
kind: row.source === "search" ? KIND_SEARCH : KIND_VISIT,
timestampMs: Math.floor(row.visitDateMicros / MICROS_PER_MS),
row,
});
}
for (const msg of chats) {
if (msg.convId == null) {
continue;
}
const t = getMessageTimestampMs(msg);
if (!Number.isFinite(t)) {
continue;
}
events.push({ kind: KIND_CHAT, timestampMs: t, row: msg });
}
events.sort((a, b) => a.timestampMs - b.timestampMs);
const sessions = [];
let cur = null;
for (const ev of events) {
const t = ev.timestampMs;
const needNew =
cur === null ||
t - cur._lastMs > gapMs ||
t - cur.session_start_ms > maxSessionMs;
if (needNew) {
cur = {
session_id: t,
session_start_ms: t,
session_end_ms: t,
_lastMs: t,
_urlHashes: new Set(),
_convIds: new Set(),
_domains: new Set(),
_titles: new Set(),
_queries: new Set(),
_visitCount: 0,
_searchCount: 0,
_totalViewTimeMs: 0,
chats: [],
};
sessions.push(cur);
}
const row = ev.row;
if (ev.kind === KIND_VISIT) {
cur._visitCount++;
cur._totalViewTimeMs += row.totalViewTimeMs || 0;
if (row.title) {
cur._titles.add(row.title);
}
if (row.urlHash != null) {
cur._urlHashes.add(row.urlHash);
}
if (row.domain) {
cur._domains.add(row.domain);
}
} else if (ev.kind === KIND_SEARCH) {
cur._searchCount++;
if (row.title) {
cur._queries.add(row.title);
}
if (row.urlHash != null) {
cur._urlHashes.add(row.urlHash);
}
if (row.domain) {
cur._domains.add(row.domain);
}
} else {
cur.chats.push(row);
cur._convIds.add(row.convId);
}
cur.session_end_ms = t;
cur._lastMs = t;
}
return sessions.map(s => ({
session_id: s.session_id,
session_start_ms: s.session_start_ms,
session_end_ms: s.session_end_ms,
visit_count: s._visitCount,
search_count: s._searchCount,
chat_count: s.chats.length,
total_view_time_ms: s._totalViewTimeMs,
chats: s.chats,
history_source_ids: [...s._urlHashes],
conversation_source_ids: [...s._convIds],
domains: [...s._domains],
titles: [...s._titles],
search_queries: [...s._queries],
}));
}
function getMessageTimestampMs(msg) {
return typeof msg.createdDate === "number"
? msg.createdDate
: (msg.createdDate?.getTime?.() ?? NaN);
}