import { jsonUtf8Bytes } from "../infra/json-utf8-bytes.js";

import { hasInterSessionUserProvenance } from "../sessions/input-provenance.js";

import { extractAssistantVisibleText } from "../shared/chat-message-content.js";

import { escapeRegExp } from "../shared/regexp.js";

import { estimateStringChars, estimateTokensFromChars } from "../utils/cjk-chars.js";

import { stripInlineDirectiveTagsForDisplay } from "../utils/directive-tags.js";

import { extractToolCallNames, hasToolCall } from "../utils/transcript-tools.js";

readSessionTranscriptIndex,

type IndexedTranscriptEntry,

} from "./session-transcript-index.fs.js";

import {

extractJsonNullableStringFieldPrefix,

extractJsonNumberFieldPrefix,

extractJsonStringFieldPrefix,

} from "./session-transcript-json.js";

import type { SessionPreviewItem } from "./session-utils.types.js";

type SessionTitleFields = {

return Buffer.byteLength(line, "utf8") > MAX_TRANSCRIPT_PARSE_LINE_BYTES;

}

function extractJsonStringFieldPrefix(prefix: string, field: string): string | undefined {

const match = new RegExp(`"${escapeRegExp(field)}"\\s*:\\s*"((?:\\\\.|[^"\\\\])*)"`).exec(prefix);

if (!match) {

return undefined;

}

try {

const decoded = JSON.parse(`"${match[1]}"`) as unknown;

return normalizeTailEntryString(decoded);

} catch {

return undefined;

}

}

function extractJsonNullableStringFieldPrefix(

prefix: string,

field: string,

): string | null | undefined {

if (new RegExp(`"${escapeRegExp(field)}"\\s*:\\s*null`).test(prefix)) {

return null;

}

return extractJsonStringFieldPrefix(prefix, field);

}

function extractJsonNumberFieldPrefix(prefix: string, field: string): number | undefined {

const match = new RegExp(

`"${escapeRegExp(field)}"\\s*:\\s*(-?\\d+(?:\\.\\d+)?(?:[eE][+-]?\\d+)?)`,

).exec(prefix);

if (!match) {

return undefined;

}

const decoded = Number(match[1]);

return Number.isFinite(decoded) ? decoded : undefined;

}

function buildOversizedTranscriptRecord(line: string): TailTranscriptRecord {

const prefix = line.slice(0, OVERSIZED_TRANSCRIPT_METADATA_PREFIX_CHARS);

const messageMatch = /"message"\s*:/.exec(prefix);

return { record };

}

function normalizeTailEntryString(value: unknown): string | undefined {

return typeof value === "string" && value.trim().length > 0 ? value : undefined;

}

function parseTailTranscriptRecord(line: string): TailTranscriptRecord | null {

if (isOversizedTranscriptLine(line)) {

return buildOversizedTranscriptRecord(line);