#!/usr/bin/env bash
set -euo pipefail

usage() {
  cat <<'EOF'
Usage:
  compare-pack-profile-runs.sh [options] [build-bin-dir] [-- <client args...>]

Examples:
  compare-pack-profile-runs.sh \
    --left-label pck \
    --left-runtime-root /srv/client-runtime-pck \
    --right-label m2p \
    --right-runtime-root /srv/client-runtime-m2p

  compare-pack-profile-runs.sh \
    --left-label legacy \
    --left-runtime-root ../runtime-pck \
    --right-label secure \
    --right-runtime-root ../runtime-m2p \
    ./build-mingw64-lld/bin -- --m2pack-strict-hash 0

Options:
  --left-runtime-root DIR   Runtime root for the first run
  --right-runtime-root DIR  Runtime root for the second run
  --left-label NAME         Label for the first run (default: left)
  --right-label NAME        Label for the second run (default: right)
  --out-dir DIR             Directory for archived reports and compare output
  --timeout SEC             Overrides M2_TIMEOUT for both runs
  --copy-runtime            Materialize runtime instead of symlinking it
  -h, --help                Show this help

Behavior:
  - Runs two captures back-to-back into the same build output
  - Archives both raw reports and summaries
  - Writes a combined compare report and prints it to stdout
EOF
}

sanitize_label() {
  printf '%s' "$1" \
    | tr '[:upper:]' '[:lower:]' \
    | sed -E 's/[^a-z0-9._-]+/-/g; s/^-+//; s/-+$//; s/-{2,}/-/g'
}

script_dir="$(cd -- "$(dirname -- "${BASH_SOURCE[0]}")" && pwd)"
repo_root="$(realpath "$script_dir/..")"
default_build_bin_dir="$repo_root/build-mingw64-lld/bin"

capture_script="${M2_CAPTURE_PACK_PROFILE_SCRIPT:-$script_dir/capture-pack-profile.sh}"
parser_script="${M2_PACK_PROFILE_PARSER:-$script_dir/pack-profile-report.py}"

left_runtime_root=""
right_runtime_root=""
left_label="left"
right_label="right"
out_dir=""
timeout_seconds="${M2_TIMEOUT:-20}"
copy_runtime=0

while [[ $# -gt 0 ]]; do
  case "$1" in
    --left-runtime-root)
      left_runtime_root="$2"
      shift 2
      ;;
    --right-runtime-root)
      right_runtime_root="$2"
      shift 2
      ;;
    --left-label)
      left_label="$2"
      shift 2
      ;;
    --right-label)
      right_label="$2"
      shift 2
      ;;
    --out-dir)
      out_dir="$2"
      shift 2
      ;;
    --timeout)
      timeout_seconds="$2"
      shift 2
      ;;
    --copy-runtime)
      copy_runtime=1
      shift
      ;;
    -h|--help)
      usage
      exit 0
      ;;
    --)
      shift
      break
      ;;
    -*)
      echo "unknown option: $1" >&2
      usage >&2
      exit 1
      ;;
    *)
      break
      ;;
  esac
done

if [[ -z "$left_runtime_root" || -z "$right_runtime_root" ]]; then
  echo "both --left-runtime-root and --right-runtime-root are required" >&2
  usage >&2
  exit 1
fi

build_bin_dir="${1:-$default_build_bin_dir}"
if [[ $# -gt 0 ]]; then
  shift
fi
build_bin_dir="$(realpath -m "$build_bin_dir")"

if [[ -z "$out_dir" ]]; then
  out_dir="$build_bin_dir/log/pack-profile-runs/$(date +%Y%m%d-%H%M%S)"
fi
out_dir="$(realpath -m "$out_dir")"
mkdir -p "$out_dir"

if [[ ! -x "$capture_script" ]]; then
  echo "capture script not executable: $capture_script" >&2
  exit 1
fi

if [[ ! -f "$parser_script" ]]; then
  echo "pack profile parser not found: $parser_script" >&2
  exit 1
fi

if ! command -v python3 >/dev/null 2>&1; then
  echo "python3 not found in PATH" >&2
  exit 1
fi

capture_common_args=(
  --out-dir "$out_dir"
  --timeout "$timeout_seconds"
)
if [[ "$copy_runtime" -eq 1 ]]; then
  capture_common_args+=(--copy-runtime)
fi

"$capture_script" \
  "${capture_common_args[@]}" \
  --runtime-root "$left_runtime_root" \
  --label "$left_label" \
  "$build_bin_dir" \
  -- "$@"

"$capture_script" \
  "${capture_common_args[@]}" \
  --runtime-root "$right_runtime_root" \
  --label "$right_label" \
  "$build_bin_dir" \
  -- "$@"

left_safe_label="$(sanitize_label "$left_label")"
right_safe_label="$(sanitize_label "$right_label")"
left_report="$out_dir/$left_safe_label.pack_profile.txt"
right_report="$out_dir/$right_safe_label.pack_profile.txt"
compare_path="$out_dir/compare-$left_safe_label-vs-$right_safe_label.txt"

python3 "$parser_script" \
  "$left_label=$left_report" \
  "$right_label=$right_report" | tee "$compare_path"

echo
echo "saved compare report: $compare_path"