y-bin-default

#!/usr/bin/env bash
[ -z "$DEBUG" ] || set -x
set -eo pipefail

YBIN="$(cd "$(dirname "$0")" && pwd)"

YHELP='y-bin-default - Ensure ystack-managed binaries take precedence via ~/.local/bin symlinks

Usage: y-bin-default [help] SUBCOMMAND [BIN...]

Subcommands:
  check               Verify symlinks exist and take precedence in PATH
  ensure              Create symlinks and verify precedence (fails if link exists but loses to PATH)

Arguments:
  BIN                  Binary name (e.g. yarn). If omitted, iterates all known defaults.

Known defaults: yarn, npx

The convention is to symlink ~/.local/bin/BIN -> $YSTACK_HOME/bin/BIN so that
the ystack-managed version takes precedence without requiring PATH changes to
$YSTACK_HOME/bin itself. Users must ensure ~/.local/bin is early in their PATH.

Dependencies:

Exit codes:
  0          Success
  1          Usage error
  2          Check or ensure failed
'

case "${1:-}" in
  help) echo "$YHELP"; exit 0 ;;
  --help) echo "$YHELP"; exit 0 ;;
esac

USER_BIN="$HOME/.local/bin"
KNOWN_DEFAULTS="yarn npx" # no_npx: manages the npx default symlink

subcmd="${1:-}"
# y-script-lint:disable=or-true # shift fails when no args after subcmd
shift || true

case "$subcmd" in
  check|ensure) ;;
  "") echo "ERROR: subcommand required (check or ensure)" >&2; exit 1 ;;
  *) echo "ERROR: unknown subcommand: $subcmd (use: check, ensure)" >&2; exit 1 ;;
esac

bins=("$@")
if [ ${#bins[@]} -eq 0 ]; then
  IFS=' ' read -ra bins <<< "$KNOWN_DEFAULTS"
fi

failed=0

for bin in "${bins[@]}"; do
  source_bin="$YBIN/$bin"
  target_link="$USER_BIN/$bin"

  if [[ "$bin" == y-* ]]; then
    echo "ERROR: refusing to install y- prefixed binary $bin (y-* binaries belong in ystack PATH, not ~/.local/bin)" >&2
    failed=1
    continue
  fi

  if [ ! -e "$source_bin" ] && [ ! -L "$source_bin" ]; then
    echo "ERROR: $source_bin does not exist" >&2
    failed=1
    continue
  fi

  link_exists=false
  link_correct=false
  if [ -L "$target_link" ]; then
    link_exists=true
    existing_target="$(readlink "$target_link")"
    if [ "$existing_target" = "$source_bin" ] || [ "$existing_target" = "$(cd "$YBIN" && pwd)/$bin" ]; then
      link_correct=true
    fi
  elif [ -e "$target_link" ]; then
    echo "ERROR: $target_link exists but is not a symlink" >&2
    failed=1
    continue
  fi

  case "$subcmd" in
    check)
      if [ "$link_exists" = "false" ]; then
        echo "MISSING $target_link -> $source_bin"
        failed=1
        continue
      fi
      if [ "$link_correct" = "false" ]; then
        echo "WRONG $target_link -> $existing_target (expected $source_bin)"
        failed=1
        continue
      fi
      ;;
    ensure)
      if [ "$link_exists" = "true" ] && [ "$link_correct" = "false" ]; then
        echo "ERROR: $target_link -> $existing_target (not managed by ystack, remove manually)" >&2
        failed=1
        continue
      fi
      if [ "$link_correct" = "false" ]; then
        mkdir -p "$USER_BIN"
        ln -s "$source_bin" "$target_link"
        echo "CREATED $target_link -> $source_bin"
      fi
      ;;
  esac

  # Check PATH precedence
  # y-script-lint:disable=or-true # command -v returns 1 when bin not in PATH
  resolved="$(command -v "$bin" 2>/dev/null || true)"
  if [ -z "$resolved" ]; then
    echo "WARN $bin not found in PATH after linking" >&2
    failed=1
    continue
  fi

  # Check that the resolved path is our symlink in USER_BIN or our bin, not some other bin earlier in PATH
  if [ "$resolved" != "$target_link" ] && [ "$resolved" != "$source_bin" ]; then
    echo "NO_PRECEDENCE $bin resolves to $resolved via $(dirname "$resolved")"
    echo "  Recommendation: ensure $USER_BIN appears before $(dirname "$resolved") in PATH" >&2
    if [ "$subcmd" = "ensure" ]; then
      failed=1
    fi
  else
    echo "OK $bin -> $resolved"
  fi
done

[ "$failed" -ne 0 ] && exit 2
exit 0