import { chmodSync, mkdirSync, writeFileSync } from "node:fs";
import path from "node:path";

// A stand-in for stagit, for the source step's tests (sourceHistory.test.ts,
// source.test.ts; the real one is tested where it is installed). It writes
// what stagit writes, where stagit writes it (its CWD), the way stagit.c does:
//   - `-c <file>`: walks from HEAD down to the commit the file names, writes a
//     log line and a page for each NEW commit, appends the file's old lines,
//     and rewrites the file (the head, then every line);
//   - `-l <n>`: a log line for the newest n and "<m> more commits remaining,
//     fetch the repository"; a page for EVERY commit that has none (-l does
//     not cap the pages);
//   - neither: a line and a page for every commit;
//   - `-c` with `-l`: stagit's usage error;
//   - and every run: files.html, refs.html, the two feeds (atom.xml carries
//     the -u base), a per-file page, a leftover in the CWD. A commit page is
//     never rewritten once it exists.
// Each call is appended to `log` as `cache=… limit=… base=… repo=<dir name>`.
// `exit` fails at once (with a stderr line); `extra` goes into every commit
// page; `pad` bytes are added to the head's page.
export function writeFakeStagit(
  file: string,
  log: string,
  o: { exit?: number; extra?: string; pad?: number } = {},
): string {
  mkdirSync(path.dirname(file), { recursive: true });
  writeFileSync(
    file,
    `#!/bin/sh
cache=""; base=""; repo=""; limit=""
while [ $# -gt 0 ]; do
  case "$1" in
    -c) cache="$2"; shift 2;;
    -l) limit="$2"; shift 2;;
    -u) base="$2"; shift 2;;
    *) repo="$1"; shift;;
  esac
done
echo "cache=$cache limit=$limit base=$base repo=$(basename "$repo")" >> '${log}'
${o.exit ? `echo 'stagit: something broke' >&2; exit ${o.exit}` : ""}
if [ -n "$cache" ] && [ -n "$limit" ]; then echo 'usage: stagit [-c cachefile | -l commits] [-u baseurl] repodir' >&2; exit 1; fi
mkdir -p commit file
tip=$(git --git-dir "$repo" rev-parse HEAD)
last=""
if [ -n "$cache" ] && [ -f "$cache" ]; then last=$(head -n 1 "$cache"); fi
: > lines.tmp
n=0; rem=0
for c in $(git --git-dir "$repo" rev-list HEAD); do
  [ "$c" = "$last" ] && break
  if [ -n "$limit" ] && [ "$n" -ge "$limit" ]; then
    rem=$((rem + 1))
    [ -f "commit/$c.html" ] && continue
  else
    n=$((n + 1))
    echo "<tr><td><a href=\\"commit/$c.html\\">$c</a></td></tr>" >> lines.tmp
  fi
  [ -f "commit/$c.html" ] || printf '<html>\\n<head>\\n</head>\\n<body>\\n<a href="../file/README.md.html">README</a> ${o.extra ?? ""}\\n</body>\\n</html>\\n' > "commit/$c.html"
done
if [ -n "$cache" ]; then
  if [ -n "$last" ]; then tail -n +2 "$cache" >> lines.tmp; fi
  { echo "$tip"; cat lines.tmp; } > "$cache"
fi
if [ "$rem" -gt 0 ]; then echo "<tr><td></td><td colspan=\\"5\\">$rem more commits remaining, fetch the repository</td></tr>" >> lines.tmp; fi
{
  printf '<html>\\n<head>\\n</head>\\n<body>\\n<span class="desc">%s</span> %s <a href="file/README.md.html">README</a> <img src="logo.png" />\\n<table id="log">\\n' "$(cat "$repo/description")" "$(cat "$repo/url")"
  cat lines.tmp
  printf '</table>\\n</body>\\n</html>\\n'
} > log.html
rm -f lines.tmp
printf '<html>\\n<head>\\n</head>\\n<body>\\n<a href="file/app/%%5Bslug%%5D/page.tsx.html">x</a>\\n</body>\\n</html>\\n' > files.html
printf '<html>\\n<head>\\n</head>\\n<body>\\n</body>\\n</html>\\n' > refs.html
printf '<feed>%s file/README.md.html</feed>\\n' "$base" > atom.xml
printf '<feed/>\\n' > tags.xml
printf 'x\\n' > file/README.md.html
touch cache.XXXXleftover
${o.pad ? `head -c ${o.pad} /dev/zero >> "commit/$tip.html"` : ""}
exit 0
`,
  );
  chmodSync(file, 0o755);
  return file;
}