#!/usr/bin/env bash
# UI drift ratchet — a one-way gate that prevents UI legacy patterns from
# growing while UI5–UI8 migrations are still in flight.
#
# How it works:
#   - Reads tracked baseline counts from scripts/ui-drift-baseline.json
#   - Counts current matches per category by re-using the same patterns
#     as scripts/ui-drift-audit.sh
#   - FAILS if any category COUNT is GREATER than its baseline
#   - PASSES (and reports the delta) if counts equal or fall below baseline
#
# Usage:
#   ./scripts/ui-drift-ratchet.sh            # check against baseline (CI mode)
#   ./scripts/ui-drift-ratchet.sh --update   # rewrite baseline to current counts
#                                            #   (commit the result with a UI
#                                            #    migration that lowered them)

set -euo pipefail

ROOT="$(git rev-parse --show-toplevel)"
cd "$ROOT"

BASELINE_FILE="scripts/ui-drift-baseline.json"

if [[ ! -f "$BASELINE_FILE" ]]; then
  echo "FAIL: missing $BASELINE_FILE" >&2
  exit 2
fi

MODE="check"
if [[ "${1:-}" == "--update" ]]; then
  MODE="update"
fi

# Detect ripgrep availability with a grep fallback (same logic as ui-drift-audit.sh).
if command -v rg >/dev/null 2>&1; then
  SEARCH_BACKEND="rg"
else
  SEARCH_BACKEND="grep"
fi

count_matches() {
  local pattern="$1"
  shift
  local n
  if [[ "$SEARCH_BACKEND" == "rg" ]]; then
    n=$(rg -n "$pattern" "$@" --glob '!**/*.test.*' 2>/dev/null | wc -l | tr -d ' ')
  else
    n=$(grep -rnE "$pattern" "$@" \
      --include="*.ts" --include="*.tsx" --include="*.js" --include="*.jsx" \
      --exclude="*.test.*" --exclude="*.spec.*" \
      --exclude-dir=node_modules --exclude-dir=.next 2>/dev/null | wc -l | tr -d ' ')
  fi
  echo "$n"
}

# Read baseline values. Avoid jq dependency by using grep + sed.
read_baseline() {
  local key="$1"
  grep -E "\"$key\"" "$BASELINE_FILE" | head -1 | sed -E 's/.*: *([0-9]+).*/\1/'
}

BASE_RAW=$(read_baseline raw_interactive_controls)
BASE_LEGACY=$(read_baseline legacy_global_surface_classes)
BASE_COLORS=$(read_baseline hardcoded_color_literals)
BASE_IMPORTS=$(read_baseline direct_bytelyst_ui_imports_outside_adapter)

CUR_RAW=$(count_matches '<button|<input|<textarea|<select' web/src/app web/src/components)
CUR_LEGACY=$(count_matches 'className="[^"]*(badge|surface-card|surface-muted|input-shell)' web/src/app web/src/components)
CUR_COLORS=$(count_matches '#[0-9a-fA-F]{3,8}|rgba?\(' web/src/app web/src/components)
# For the adapter exclusion, filter out the adapter file post-hoc since we
# want a stable raw count.
CUR_IMPORTS_RAW=$(count_matches 'from "@bytelyst/ui"|from '\''@bytelyst/ui'\''' web/src/app web/src/components)
# Adapter file is allowed to import @bytelyst/ui; subtract one line per
# import line in Primitives.tsx so the ratchet doesn't drift just because
# the adapter grows its re-export list.
ADAPTER_LINES=$(grep -cE 'from "@bytelyst/ui"|from '\''@bytelyst/ui'\''' web/src/components/ui/Primitives.tsx 2>/dev/null || echo 0)
CUR_IMPORTS=$((CUR_IMPORTS_RAW - ADAPTER_LINES))
if [[ "$CUR_IMPORTS" -lt 0 ]]; then CUR_IMPORTS=0; fi

if [[ "$MODE" == "update" ]]; then
  cat >"$BASELINE_FILE" <<JSON
{
  "//": "Baseline UI drift counts. Updated $(date -u +%Y-%m-%dT%H:%M:%SZ) by scripts/ui-drift-ratchet.sh --update. Commit alongside the migration that lowered the counts.",
  "raw_interactive_controls": $CUR_RAW,
  "legacy_global_surface_classes": $CUR_LEGACY,
  "hardcoded_color_literals": $CUR_COLORS,
  "direct_bytelyst_ui_imports_outside_adapter": $CUR_IMPORTS
}
JSON
  echo "Wrote new baseline to $BASELINE_FILE"
  cat "$BASELINE_FILE"
  exit 0
fi

# Compare and report.
failures=0
report() {
  local title="$1"
  local cur="$2"
  local base="$3"
  if [[ "$cur" -gt "$base" ]]; then
    printf "  ✗ %-50s %4d (baseline %d, +%d) — REGRESSION\n" "$title" "$cur" "$base" "$((cur - base))"
    failures=$((failures + 1))
  elif [[ "$cur" -lt "$base" ]]; then
    printf "  ↓ %-50s %4d (baseline %d, -%d) — progress, run --update\n" "$title" "$cur" "$base" "$((base - cur))"
  else
    printf "  = %-50s %4d (at baseline)\n" "$title" "$cur"
  fi
}

echo "UI drift ratchet (baseline: $BASELINE_FILE)"
report "raw interactive controls"               "$CUR_RAW"     "$BASE_RAW"
report "legacy global surface classes"          "$CUR_LEGACY"  "$BASE_LEGACY"
report "hardcoded color literals"               "$CUR_COLORS"  "$BASE_COLORS"
report "direct @bytelyst/ui imports outside adapter" "$CUR_IMPORTS" "$BASE_IMPORTS"

if [[ "$failures" -gt 0 ]]; then
  echo
  echo "FAIL: $failures category/categories regressed above baseline." >&2
  echo "      Migrate the new call site(s) to @bytelyst/ui primitives via" >&2
  echo "      @/components/ui/Primitives, or — if migration lowered other" >&2
  echo "      counts — run 'pnpm run audit:ui:ratchet:update' and commit." >&2
  exit 1
fi

echo
echo "OK — no UI drift regressions above baseline."