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

# ==============================================================================
# perf/make-shell-fixture.sh
# Archives frontend from <commit> into perf/fixtures/shell-<tag>/,
# computes the build tag the way server.js computeBuildTag() does,
# and verifies that it matches expected-tag (or live prod tag).
# ==============================================================================

if [ $# -lt 1 ]; then
  echo "Usage: $0 <commit> [expected-tag]" >&2
  exit 1
fi

COMMIT="$1"
EXPECTED_TAG="${2:-}"

REPO_ROOT="$(cd "$(dirname "$0")/.." && pwd)"
PERF_DIR="$REPO_ROOT/perf"
FIXTURES_DIR="$PERF_DIR/fixtures"
TMP_DIR="$PERF_DIR/.tmp"

mkdir -p "$FIXTURES_DIR" "$TMP_DIR"

PROD_URL="https://worship.hesed.sbs/api/version"

fetch_prod_tag() {
  curl -s -S --max-time 10 "$PROD_URL" | node -e '
    let data = "";
    process.stdin.on("data", chunk => { data += chunk; });
    process.stdin.on("end", () => {
      try {
        const j = JSON.parse(data);
        if (j.buildTag) {
          process.stdout.write(j.buildTag);
          process.exit(0);
        }
      } catch {}
      process.exit(1);
    });
  ' 2>/dev/null || echo ""
}

# Verify the commit exists in git
if ! git rev-parse --verify "$COMMIT^{commit}" >/dev/null 2>&1; then
  echo "Error: commit '$COMMIT' not found in git repository" >&2
  exit 1
fi

RESOLVED_COMMIT="$(git rev-parse --short=7 "$COMMIT")"
echo "Extracting frontend from commit $RESOLVED_COMMIT..."

STAGING_DIR="$(mktemp -d "$TMP_DIR/fixture-staging-XXXXXX")"
cleanup() {
  rm -rf "$STAGING_DIR"
}
trap cleanup EXIT

# Archive frontend tree into staging dir
git archive "$COMMIT" frontend | tar -x -C "$STAGING_DIR" --strip-components=1

# Compute build tag using the exact logic from server/server.js computeBuildTag()
COMPUTED_TAG=$(node -e '
const { createHash } = require("crypto");
const { readdirSync, statSync, readFileSync } = require("fs");

function computeTag(dir) {
  const hash = createHash("sha256");
  const walk = (d, prefix) => {
    for (const name of readdirSync(d).sort()) {
      const full = `${d}/${name}`;
      const rel = `${prefix}/${name}`;
      if (statSync(full).isDirectory()) {
        walk(full, rel);
      } else {
        hash.update(rel);
        hash.update(readFileSync(full));
      }
    }
  };
  walk(dir, "./public");
  return hash.digest("hex").slice(0, 12);
}

const tag = computeTag(process.argv[1]);
process.stdout.write(tag);
' "$STAGING_DIR")

echo "Computed build tag for $RESOLVED_COMMIT: $COMPUTED_TAG"

# Determine target expected tag
if [ -z "$EXPECTED_TAG" ]; then
  echo "Querying live production tag from $PROD_URL..."
  EXPECTED_TAG="$(fetch_prod_tag)"
  if [ -z "$EXPECTED_TAG" ]; then
    echo "Error: failed to fetch live buildTag from $PROD_URL" >&2
    exit 1
  fi
  echo "Live production build tag: $EXPECTED_TAG"

  # If mismatch, deploy might be in progress: wait 5 minutes and retry once
  if [ "$COMPUTED_TAG" != "$EXPECTED_TAG" ]; then
    echo "Tag mismatch detected (computed=$COMPUTED_TAG vs prod=$EXPECTED_TAG)."
    echo "Deploy may be in progress. Waiting 300 seconds to retry once..."
    sleep 300
    EXPECTED_TAG="$(fetch_prod_tag)"
    echo "Retried production build tag: $EXPECTED_TAG"
  fi
fi

if [ "$COMPUTED_TAG" != "$EXPECTED_TAG" ]; then
  echo "Error: build tag mismatch! Computed '$COMPUTED_TAG' does not match expected '$EXPECTED_TAG'" >&2
  exit 1
fi

TARGET_FIXTURE_DIR="$FIXTURES_DIR/shell-$COMPUTED_TAG"
echo "Installing fixture into $TARGET_FIXTURE_DIR..."
rm -rf "$TARGET_FIXTURE_DIR"
mkdir -p "$TARGET_FIXTURE_DIR"
cp -a "$STAGING_DIR"/. "$TARGET_FIXTURE_DIR"/

FILE_COUNT=$(find "$TARGET_FIXTURE_DIR" -type f | wc -l)
echo "Success: shell fixture created at $TARGET_FIXTURE_DIR with $FILE_COUNT files."
echo "Verified commit: $RESOLVED_COMMIT"
echo "Verified build tag: $COMPUTED_TAG"