#!/usr/bin/env bash
# Verifies the claims in how-to-install-rubygems-ubuntu.html.
# Standalone-safe: makes no lasting changes to the machine (any probe
# directory it creates to test writability is removed immediately).
set -u

PASS=0
FAIL=0
SKIP=0
CONTENT=0

pass() { echo "PASS: $1"; PASS=$((PASS+1)); }
fail() { echo "FAIL: $1"; FAIL=$((FAIL+1)); }
skip() { echo "SKIP: $1"; SKIP=$((SKIP+1)); }
content() { echo "CONTENT: $1"; CONTENT=$((CONTENT+1)); }

# --- Claim: ruby and gem are both runnable, and gem -v succeeds without any
#     separate "install RubyGems" step having been performed by this script. ---
if ! command -v ruby >/dev/null 2>&1; then
  skip "ruby not found on PATH — cannot check bundled RubyGems"
else
  RUBY_VER="$(ruby -v 2>&1)"
  pass "ruby -v ran: $RUBY_VER"

  if ! command -v gem >/dev/null 2>&1; then
    fail "ruby is installed but gem is not on PATH — this would contradict the article's bundling claim"
  else
    GEM_VER="$(gem -v 2>&1)"
    if [[ "$GEM_VER" =~ ^[0-9]+\.[0-9]+ ]]; then
      pass "gem -v ran with no separate install step: $GEM_VER"
    else
      fail "gem -v did not return a version number: $GEM_VER"
    fi
  fi
fi

# --- Claim: the system/default gem install directory is not writable
#     without sudo, but the user install directory is — without creating
#     any lasting files (probe file is removed immediately either way). ---
if command -v gem >/dev/null 2>&1; then
  SYS_DIR="$(gem environment gemdir 2>/dev/null)"
  if [[ -n "$SYS_DIR" && -d "$SYS_DIR" ]]; then
    PROBE="$SYS_DIR/.verify_probe_$$"
    if ( touch "$PROBE" ) 2>/dev/null; then
      rm -f "$PROBE"
      skip "system gem dir ($SYS_DIR) IS writable without sudo on this machine — the SIP-protected-path claim is macOS-specific and doesn't hold everywhere; not a failure"
    else
      pass "system gem dir ($SYS_DIR) is NOT writable without sudo, matching the article's finding"
    fi
  else
    skip "could not determine system gem dir — cannot test writability"
  fi

  USER_DIR="$(gem environment | grep 'USER INSTALLATION DIRECTORY' | sed 's/.*: *//')"
  if [[ -n "$USER_DIR" ]]; then
    PRE_EXISTED=0
    [[ -d "$USER_DIR" ]] && PRE_EXISTED=1
    mkdir -p "$USER_DIR" 2>/dev/null
    PROBE="$USER_DIR/.verify_probe_$$"
    if ( touch "$PROBE" ) 2>/dev/null; then
      rm -f "$PROBE"
      pass "user gem dir ($USER_DIR) is writable without sudo, matching the article's --user-install claim"
    else
      fail "user gem dir ($USER_DIR) was not writable without sudo"
    fi
    # Clean up: if this script created the directory (it did not pre-exist),
    # remove it so the script leaves no trace, same as the article's own probe.
    if [[ "$PRE_EXISTED" -eq 0 ]]; then
      rmdir "$USER_DIR" 2>/dev/null
      rmdir "$(dirname "$USER_DIR")" 2>/dev/null
    fi
  else
    skip "could not determine user gem install directory"
  fi
else
  skip "gem not available — cannot test system/user gem dir writability"
fi

# --- Ubuntu-specific claims (ruby-full pulls Ruby 3.2 on 24.04, apt install
#     ruby-full) are cited from packages.ubuntu.com, not executable here
#     unless this is actually Ubuntu with apt available. ---
if [[ -f /etc/os-release ]] && grep -qi ubuntu /etc/os-release 2>/dev/null && command -v apt-cache >/dev/null 2>&1; then
  APT_VER="$(apt-cache policy ruby-full 2>/dev/null | grep Candidate | awk '{print $2}')"
  if [[ -n "$APT_VER" ]]; then
    pass "apt-cache reports ruby-full candidate version: $APT_VER (compare to article's cited 1:3.2~ubuntu1 for 24.04)"
  else
    skip "apt-cache could not resolve a candidate version for ruby-full"
  fi
else
  skip "not running on Ubuntu with apt available — ruby-full package version claim is a citation to packages.ubuntu.com, not executable here"
fi

ARTICLE="$(dirname "$0")/how-to-install-rubygems-ubuntu.html"
if [[ -f "$ARTICLE" ]]; then
  grep -q "RubyGems ships with Ruby" "$ARTICLE" && content "article cites the RubyGems bundling guide" || fail "article missing the RubyGems bundling citation"
  grep -q -- "--user-install" "$ARTICLE" && content "article explains --user-install as the sudo alternative" || fail "article missing --user-install guidance"
else
  skip "article HTML not present alongside script — content checks skipped (expected for a standalone /verify/ download)"
  skip "article HTML not present alongside script — content checks skipped (expected for a standalone /verify/ download)"
fi

echo "PASS=$PASS FAIL=$FAIL SKIP=$SKIP CONTENT=$CONTENT"
[[ $FAIL -eq 0 ]]