import type { InlineCodeState } from "../markdown/code-spans.js";

import { buildCodeSpanIndex, createInlineCodeState } from "../markdown/code-spans.js";

import { normalizeOptionalString } from "../shared/string-coerce.js";

import { findFinalTagMatches } from "../shared/text/final-tags.js";

import { hasOrphanReasoningCloseBoundary } from "../shared/text/reasoning-tags.js";

import { mediaUrlsFromGeneratedAttachments } from "./generated-attachments.js";

import { EmbeddedBlockChunker } from "./pi-embedded-block-chunker.js";

import { stripDowngradedToolCallText, THINKING_TAG_SCAN_RE } from "./pi-embedded-utils.js";

import { hasNonzeroUsage, normalizeUsage, type UsageLike } from "./usage.js";

const FINAL_TAG_SCAN_RE = /<\s*(\/?)\s*final\s*>/gi;

const STREAM_STRIPPED_BLOCK_TAG_NAMES = [

"final",

"think",

if (!fragment.startsWith("<") || fragment.includes(">")) {

return false;

}

const normalized = fragment.toLowerCase().replace(/\s+/g, "");

if (!normalized.startsWith("<")) {

return false;

const body = fragment.toLowerCase().slice(1).trimStart().replace(/^\//, "").trimStart();

if (!body) {

return true;

}

const candidate = normalized.slice(1).replace(/^\//, "");

if (!candidate) {

const namePart = body.split(/[\s/>]/, 1)[0] ?? "";

if (!namePart) {

return true;

}

return STREAM_STRIPPED_BLOCK_TAG_NAMES.some((name) => name.startsWith(candidate));

return STREAM_STRIPPED_BLOCK_TAG_NAMES.some((name) => {

return name.startsWith(namePart) || namePart === name;

});

}

function splitTrailingBlockTagFragment(

const finalCodeSpans = buildCodeSpanIndex(processed, inlineStateStart);

if (!params.enforceFinalTag) {

state.inlineCode = finalCodeSpans.inlineState;

FINAL_TAG_SCAN_RE.lastIndex = 0;

return stripTagsOutsideCodeSpans(processed, FINAL_TAG_SCAN_RE, finalCodeSpans.isInside);

return stripFinalTagsOutsideCodeSpans(processed, finalCodeSpans.isInside);

}

// If enforcement is enabled, only return text that appeared inside a <final> block.

let result = "";

FINAL_TAG_SCAN_RE.lastIndex = 0;

let lastFinalIndex = 0;

let inFinal = state.final;

let everInFinal = state.final;

for (const match of processed.matchAll(FINAL_TAG_SCAN_RE)) {

const idx = match.index ?? 0;

for (const match of findFinalTagMatches(processed)) {

const idx = match.index;

if (finalCodeSpans.isInside(idx)) {

continue;

}

const isClose = match[1] === "/";

const isClose = match.isClose;

const isSelfClosing = match.isSelfClosing;

if (!inFinal && !isClose) {

if (isSelfClosing) {

if (inFinal) {

result += processed.slice(lastFinalIndex, idx);

inFinal = false;

} else {

inFinal = true;

everInFinal = true;

}

lastFinalIndex = idx + match.text.length;

} else if (!inFinal && !isClose) {

// Found <final> start tag.

inFinal = true;

everInFinal = true;

lastFinalIndex = idx + match[0].length;

lastFinalIndex = idx + match.text.length;

} else if (inFinal && isClose) {

// Found </final> end tag.

result += processed.slice(lastFinalIndex, idx);

inFinal = false;

lastFinalIndex = idx + match[0].length;

lastFinalIndex = idx + match.text.length;

}

}

// missed (e.g. nested tags or hallucinations) to prevent leakage.

const resultCodeSpans = buildCodeSpanIndex(result, inlineStateStart);

state.inlineCode = resultCodeSpans.inlineState;

return stripTagsOutsideCodeSpans(result, FINAL_TAG_SCAN_RE, resultCodeSpans.isInside);

return stripFinalTagsOutsideCodeSpans(result, resultCodeSpans.isInside);

};

const stripTagsOutsideCodeSpans = (

text: string,

pattern: RegExp,

isInside: (index: number) => boolean,

) => {

const stripFinalTagsOutsideCodeSpans = (text: string, isInside: (index: number) => boolean) => {

let output = "";

let lastIndex = 0;

pattern.lastIndex = 0;

for (const match of text.matchAll(pattern)) {

const idx = match.index ?? 0;

for (const match of findFinalTagMatches(text)) {

const idx = match.index;

if (isInside(idx)) {

continue;

}

output += text.slice(lastIndex, idx);

lastIndex = idx + match[0].length;

lastIndex = idx + match.text.length;

}

output += text.slice(lastIndex);

return output;