#!/usr/bin/env bash
# Recomputes the coverage dashboard after a merge and commits what changed, as one commit
# on the current branch. The one entry point for keeping the README's coverage table
# current: bench/after-land.sh runs it in the primary checkout after every landing, so a
# spec that edits docs/feature-map.json no longer has to run `npm run dashboard` and
# commit its output.
#
#   bench/dashboard-update.sh [--no-commit]
#
# Run from anywhere inside a checkout; it works on that checkout's root. Steps:
#   1. refuse if docs/dashboard.json, docs/dashboard-history.json,
#      docs/dashboard-history.svg or README.md has uncommitted changes (they are this
#      script's to write)
#   2. node oracle/suites/dashboard.mjs --check: when every file already matches a fresh
#      computation (the date alone is allowed to differ), print "unchanged" and exit 0
#      with nothing written and nothing committed
#   3. otherwise node oracle/suites/dashboard.mjs --render rewrites the four files
#   4. commit exactly the files that changed ("dashboard: regenerate ..."), unless
#      --no-commit
#
# The computation is offline (browser-compat-data from oracle/node_modules and
# docs/feature-map.json) and takes seconds, so it runs in place like
# bench/web-features-update.sh. docs/feature-map.json is an input, never written here.
#
# Exit 0 when the dashboard is current afterwards (committed, or unchanged); 1 on any
# failure, with the reason on stderr and the four files put back as they were, so a
# failure never leaves the checkout dirty and never touches anything else. It never
# merges, resets or pushes. Rules and format: docs/dashboard.md.
set -euo pipefail

NO_COMMIT=0
for arg in "$@"; do
  case "$arg" in
    --no-commit) NO_COMMIT=1 ;;
    *) echo "usage: bench/dashboard-update.sh [--no-commit]" >&2; exit 1 ;;
  esac
done

ROOT="$(git -C "$(dirname "${BASH_SOURCE[0]}")" rev-parse --show-toplevel)"
cd "$ROOT"
FILES=(docs/dashboard.json docs/dashboard-history.json docs/dashboard-history.svg README.md)

if [ -n "$(git status --porcelain -- "${FILES[@]}")" ]; then
  echo "dashboard not updated: ${FILES[*]} has uncommitted changes" >&2
  exit 1
fi

DONE=0
restore() {
  local code=$?
  if [ "$DONE" = 0 ]; then
    git reset -q -- "${FILES[@]}" 2>/dev/null || true
    git checkout -q -- "${FILES[@]}" 2>/dev/null || true
    # A file the checkout did not track yet is removed rather than left behind.
    local f
    for f in "${FILES[@]}"; do
      git ls-files --error-unmatch "$f" >/dev/null 2>&1 || rm -f "$f"
    done
  fi
  exit "$code"
}
trap restore EXIT

if node oracle/suites/dashboard.mjs --check >/dev/null 2>&1; then
  DONE=1
  echo "dashboard unchanged"
  exit 0
fi

if ! node oracle/suites/dashboard.mjs --render >&2; then
  echo "dashboard not updated: the generator failed" >&2
  exit 1
fi

CHANGED=()
for f in "${FILES[@]}"; do
  if [ -n "$(git status --porcelain -- "$f")" ]; then CHANGED+=("$f"); fi
done
if [ "${#CHANGED[@]}" = 0 ]; then
  DONE=1
  echo "dashboard unchanged"
  exit 0
fi

if [ "$NO_COMMIT" = 1 ]; then
  DONE=1
  echo "dashboard regenerated: ${CHANGED[*]} (not committed)"
  exit 0
fi

AT="$(git rev-parse --short HEAD)"
git add -- "${CHANGED[@]}"
if ! git commit -q -m "dashboard: regenerate at $AT" -- "${CHANGED[@]}"; then
  echo "dashboard not updated: the commit failed" >&2
  exit 1
fi
DONE=1
echo "dashboard committed at $(git rev-parse --short HEAD): ${CHANGED[*]}"