import { parsePatchFiles } from "@pierre/diffs/utils/parsePatchFiles";import type { FileDiffMetadata } from "@pierre/diffs/types"; export const DIFF_THEME_NAMES = {  light: "pierre-light",  dark: "pierre-dark",} as const; export type DiffThemeName = (typeof DIFF_THEME_NAMES)[keyof typeof DIFF_THEME_NAMES]; export function resolveDiffThemeName(theme: "light" | "dark"): DiffThemeName {  return theme === "dark" ? DIFF_THEME_NAMES.dark : DIFF_THEME_NAMES.light;} const FNV_OFFSET_BASIS_32 = 0x811c9dc5;const FNV_PRIME_32 = 0x01000193;const SECONDARY_HASH_SEED = 0x9e3779b9;const SECONDARY_HASH_MULTIPLIER = 0x85ebca6b; export function fnv1a32(  input: string,  seed = FNV_OFFSET_BASIS_32,  multiplier = FNV_PRIME_32,): number {  let hash = seed >>> 0;  for (let index = 0; index < input.length; index += 1) {    hash ^= input.charCodeAt(index);    hash = Math.imul(hash, multiplier) >>> 0;  }  return hash >>> 0;} export function buildPatchCacheKey(patch: string, scope = "diff-panel"): string {  const normalizedPatch = patch.trim();  const primary = fnv1a32(normalizedPatch, FNV_OFFSET_BASIS_32, FNV_PRIME_32).toString(36);  const secondary = fnv1a32(    normalizedPatch,    SECONDARY_HASH_SEED,    SECONDARY_HASH_MULTIPLIER,  ).toString(36);  return `${scope}:${normalizedPatch.length}:${primary}:${secondary}`;} export type RenderablePatch =  | {      kind: "files";      files: FileDiffMetadata[];    }  | {      kind: "raw";      text: string;      reason: string;    }; export interface DiffLineStat {  additions: number;  deletions: number;} export function getDiffLineStat(files: ReadonlyArray<FileDiffMetadata>): DiffLineStat {  return files.reduce<DiffLineStat>(    (total, file) => {      for (const hunk of file.hunks) {        total.additions += hunk.additionLines;        total.deletions += hunk.deletionLines;      }       return total;    },    { additions: 0, deletions: 0 },  );} interface RenderablePatchOptions {  /**   * Pierre's partial-patch parser keeps hunk render starts in source-file   * coordinates. Its virtualizer iterates partial patches as compact rows, so   * review diffs need compact render starts while retaining collapsedBefore   * for the "N unmodified lines" separator.   */  compactPartialHunkOffsets?: boolean;} export function compactPartialHunkOffsets(file: FileDiffMetadata): FileDiffMetadata {  if (!file.isPartial) return file;   let splitLineStart = 0;  let unifiedLineStart = 0;  const hunks = file.hunks.map((hunk) => {    const compactHunk = {      ...hunk,      splitLineStart,      unifiedLineStart,    };    splitLineStart += hunk.splitLineCount;    unifiedLineStart += hunk.unifiedLineCount;    return compactHunk;  });   return {    ...file,    hunks,    splitLineCount: splitLineStart,    unifiedLineCount: unifiedLineStart,    ...(file.cacheKey ? { cacheKey: `${file.cacheKey}:compact-partial` } : {}),  };} export function getRenderablePatch(  patch: string | undefined,  cacheScope = "diff-panel",  options: RenderablePatchOptions = {},): RenderablePatch | null {  if (!patch) return null;  const normalizedPatch = patch.trim();  if (normalizedPatch.length === 0) return null;   try {    const parsedPatches = parsePatchFiles(      normalizedPatch,      buildPatchCacheKey(normalizedPatch, cacheScope),    );    const files = parsedPatches.flatMap((parsedPatch) =>      options.compactPartialHunkOffsets        ? parsedPatch.files.map(compactPartialHunkOffsets)        : parsedPatch.files,    );    if (files.length > 0) {      return { kind: "files", files };    }     return {      kind: "raw",      text: normalizedPatch,      reason: "Unsupported diff format. Showing raw patch.",    };  } catch {    return {      kind: "raw",      text: normalizedPatch,      reason: "Failed to parse patch. Showing raw patch.",    };  }} export function resolveFileDiffPath(fileDiff: FileDiffMetadata): string {  const raw = fileDiff.name ?? fileDiff.prevName ?? "";  if (raw.startsWith("a/") || raw.startsWith("b/")) {    return raw.slice(2);  }  return raw;} /** * What the file was called before the change. Only a rename makes it differ from the current * path, and the hosts that resolve a diff position against both sides need both names. */export function resolveFileDiffPreviousPath(fileDiff: FileDiffMetadata): string {  const raw = fileDiff.prevName ?? fileDiff.name ?? "";  if (raw.startsWith("a/") || raw.startsWith("b/")) {    return raw.slice(2);  }  return raw;} export function buildFileDiffIdentityKey(fileDiff: FileDiffMetadata): string {  return `${resolveFileDiffPreviousPath(fileDiff)}\u0000${resolveFileDiffPath(fileDiff)}`;} export function buildFileDiffRenderKey(fileDiff: FileDiffMetadata): string {  const cacheKey = fileDiff.cacheKey;  if (!cacheKey) return `${fileDiff.prevName ?? "none"}:${fileDiff.name}`;   return cacheKey.endsWith(":hydrated") ? cacheKey.slice(0, -":hydrated".length) : cacheKey;} function hashFileDiffPart(hash: number, value: string | number | boolean | undefined): number {  const serialized = value === undefined ? "undefined" : String(value);  const withLength = fnv1a32(`${typeof value}:${serialized.length}:`, hash);  return fnv1a32(serialized, withLength);} /** * Content-only version for CodeView reconciliation. Pierre's cache key includes * the whole patch, so using it here would repaint every file when one changes. */export function buildFileDiffContentVersion(fileDiff: FileDiffMetadata): number {  let hash = FNV_OFFSET_BASIS_32;  const append = (value: string | number | boolean | undefined) => {    hash = hashFileDiffPart(hash, value);  };   append(fileDiff.name);  append(fileDiff.prevName);  append(fileDiff.lang);  append(fileDiff.newObjectId);  append(fileDiff.prevObjectId);  append(fileDiff.mode);  append(fileDiff.prevMode);  append(fileDiff.type);  append(fileDiff.isPartial);  append(fileDiff.splitLineCount);  append(fileDiff.unifiedLineCount);   for (const line of fileDiff.additionLines) append(line);  for (const line of fileDiff.deletionLines) append(line);  for (const hunk of fileDiff.hunks) {    append(hunk.collapsedBefore);    append(hunk.additionStart);    append(hunk.additionCount);    append(hunk.additionLines);    append(hunk.additionLineIndex);    append(hunk.deletionStart);    append(hunk.deletionCount);    append(hunk.deletionLines);    append(hunk.deletionLineIndex);    append(hunk.hunkContext);    append(hunk.hunkSpecs);    append(hunk.splitLineStart);    append(hunk.splitLineCount);    append(hunk.unifiedLineStart);    append(hunk.unifiedLineCount);    append(hunk.noEOFCRAdditions);    append(hunk.noEOFCRDeletions);    for (const content of hunk.hunkContent) {      append(content.type);      append(content.additionLineIndex);      append(content.deletionLineIndex);      append(content.type === "change" ? content.additions : content.lines);      append(content.type === "change" ? content.deletions : undefined);    }  }   return hash;} export function getDiffCollapseIconClassName(fileDiff: FileDiffMetadata): string {  switch (fileDiff.type) {    case "new":      return "text-[var(--diffs-addition-base)]";    case "deleted":      return "text-[var(--diffs-deletion-base)]";    case "change":    case "rename-pure":    case "rename-changed":      return "text-[var(--diffs-modified-base)]";    default:      return "text-muted-foreground/80";  }} /** * Maps every diff/file surface the @pierre/diffs renderer paints onto the * app's code tokens, so themed palettes reach the code body, gutter, and * row tints instead of the renderer's bundled colors. Shared by the diff * panel and the file preview. */export const DIFF_SURFACE_THEME_UNSAFE_CSS = `[data-diffs-header],[data-diff],[data-file],[data-error-wrapper],[data-virtualizer-buffer] {  --diffs-header-font-family: var(--font-sans) !important;  --diffs-font-family: var(--font-mono) !important;  --diffs-bg: var(--code-background) !important;  --diffs-light-bg: var(--code-background) !important;  --diffs-dark-bg: var(--code-background) !important;  --diffs-token-light-bg: transparent;  --diffs-token-dark-bg: transparent;   /* Gutter, context, and row tints all derive from the code surface the diff     body sits on — mixing from the canvas leaves the gutter looking unthemed     when a palette separates the two. */  --diffs-bg-context-override: color-mix(in srgb, var(--code-background) 97%, var(--code-foreground));  --diffs-bg-hover-override: color-mix(in srgb, var(--code-background) 94%, var(--code-foreground));  --diffs-bg-separator-override: color-mix(    in srgb,    var(--code-background) 95%,    var(--code-foreground)  );  --diffs-bg-buffer-override: color-mix(in srgb, var(--code-background) 90%, var(--code-foreground));   --diffs-bg-addition-override: light-dark(    color-mix(in srgb, var(--code-background) 50%, var(--success)),    color-mix(in srgb, var(--code-background) 70%, var(--success))  );  --diffs-bg-addition-number-override: light-dark(    color-mix(in srgb, var(--code-background) 35%, var(--success)),    color-mix(in srgb, var(--code-background) 60%, var(--success))  );  --diffs-bg-addition-hover-override: color-mix(in srgb, var(--code-background) 85%, var(--success));  --diffs-bg-addition-emphasis-override: color-mix(    in srgb,    var(--code-background) 80%,    var(--success)  );   --diffs-bg-deletion-override: light-dark(    color-mix(in srgb, var(--code-background) 50%, var(--destructive)),    color-mix(in srgb, var(--code-background) 70%, var(--destructive))  );  --diffs-bg-deletion-number-override: light-dark(    color-mix(in srgb, var(--code-background) 35%, var(--destructive)),    color-mix(in srgb, var(--code-background) 60%, var(--destructive))  );  --diffs-bg-deletion-hover-override: color-mix(    in srgb,    var(--code-background) 85%,    var(--destructive)  );  --diffs-bg-deletion-emphasis-override: color-mix(    in srgb,    var(--code-background) 80%,    var(--destructive)  );   background-color: var(--diffs-bg) !important;  color: var(--code-foreground) !important;}`;