Initial commit: omp-edit DSH plugin (oh-my-pi port) with docs and tests

lib/text.js

@@ -0,0 +1,78 @@
+// Text helpers shared by every edit mode: line splitting that remembers the
+// trailing newline, snapshot tags, and compact numbered previews.
+import crypto from 'node:crypto'
+
+/** Normalize CRLF/CR to LF. */
+export const toLF = (s) => String(s).replace(/\r\n?/g, '\n')
+
+/** Split LF text into lines plus whether it ended with a newline. Empty text has no lines. */
+export function splitLines(text) {
+  const t = toLF(text)
+  if (t === '') return { lines: [], eol: false }
+  const eol = t.endsWith('\n')
+  const lines = (eol ? t.slice(0, -1) : t).split('\n')
+  return { lines, eol }
+}
+
+/** Inverse of splitLines. A file that gained content keeps (or adopts) a trailing newline. */
+export function joinLines(lines, eol) {
+  if (lines.length === 0) return ''
+  return lines.join('\n') + (eol ? '\n' : '')
+}
+
+/** Dominant line ending of the original file, so writes preserve CRLF files. */
+export function detectEol(raw) {
+  const crlf = (raw.match(/\r\n/g) || []).length
+  const lf = (raw.match(/\n/g) || []).length - crlf
+  return crlf > lf ? '\r\n' : '\n'
+}
+export const restoreEol = (lfText, eol) => (eol === '\r\n' ? lfText.replace(/\n/g, '\r\n') : lfText)
+
+/** Four uppercase hex characters derived from the whole LF-normalized file. */
+export function fileTag(text) {
+  return crypto.createHash('sha256').update(toLF(text)).digest('hex').slice(0, 4).toUpperCase()
+}
+
+export const HEADER_RE = /^\[(.+?)#([0-9A-Fa-f]{4})\]\s*$/
+
+export const formatHeader = (path, tag) => `[${path}#${tag}]`
+export const numbered = (n, text) => `${n}:${text}`
+
+/**
+ * Compact post-edit preview: changed regions of the new text (by line numbers)
+ * with `context` lines around them, separated by `…`.
+ * @param {string[]} lines new file lines
+ * @param {Array<[number, number]>} regions 1-based inclusive [start, end] in new numbering
+ */
+export function preview(lines, regions, { context = 2, maxLines = 80 } = {}) {
+  if (!regions.length || !lines.length) return []
+  const spans = regions
+    .map(([a, b]) => [Math.max(1, a - context), Math.min(lines.length, Math.max(a, b) + context)])
+    .sort((x, y) => x[0] - y[0])
+  const merged = []
+  for (const s of spans) {
+    const last = merged.at(-1)
+    if (last && s[0] <= last[1] + 1) last[1] = Math.max(last[1], s[1])
+    else merged.push([...s])
+  }
+  const out = []
+  for (const [a, b] of merged) {
+    if (out.length) out.push('…')
+    for (let n = a; n <= b; n++) {
+      if (out.length >= maxLines) { out.push('… (preview truncated; read the file for more)'); return out }
+      out.push(numbered(n, lines[n - 1]))
+    }
+  }
+  return out
+}
+
+/** Error type that carries a model-facing message. */
+export class EditError extends Error {
+  constructor(message, extra = {}) {
+    super(message)
+    this.name = 'EditError'
+    Object.assign(this, extra)
+  }
+}
+
+export const jsonQuote = (s) => JSON.stringify(String(s))