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

if [[ "$#" -lt 2 || "$#" -gt 3 ]]; then
  echo "usage: $0 <40-char-git-sha> <source-dir> [web-root]" >&2
  exit 2
fi

release_sha="$1"
source_dir="$2"
web_root="${3:-/srv/www/quant-os}"

if [[ ! "${release_sha}" =~ ^[0-9a-f]{40}$ ]]; then
  echo "release SHA must be a 40-character lowercase Git SHA" >&2
  exit 2
fi
if [[ ! -d "${source_dir}" ]]; then
  echo "source directory does not exist" >&2
  exit 2
fi
if [[ -L "${source_dir}" ]]; then
  echo "source directory must not be a symlink" >&2
  exit 2
fi
if [[ "${web_root}" != /* || "${web_root}" == "/" ]]; then
  echo "web root must be an explicit absolute non-root path" >&2
  exit 2
fi

source_entries=()
while IFS= read -r -d '' entry; do
  source_entries+=("${entry}")
done < <(find "${source_dir}" -mindepth 1 -maxdepth 1 -print0)
if [[ "${#source_entries[@]}" != "2" ]]; then
  echo "source must contain exactly index.html and status-data.js" >&2
  exit 1
fi
for required in index.html status-data.js; do
  if [[ ! -f "${source_dir}/${required}" || -L "${source_dir}/${required}" ]]; then
    echo "source must contain a regular non-symlink ${required}" >&2
    exit 1
  fi
done
for entry in "${source_entries[@]}"; do
  case "$(basename "${entry}")" in
    index.html|status-data.js)
      ;;
    *)
      echo "unexpected source entry: $(basename "${entry}")" >&2
      exit 1
      ;;
  esac
  if [[ ! -f "${entry}" || -L "${entry}" ]]; then
    echo "source entries must be regular non-symlink files" >&2
    exit 1
  fi
done

release_dir="${web_root}/releases/${release_sha}"
incoming_dir="${web_root}/.incoming-${release_sha}"
lock_dir="${web_root}/.status-deploy.lock"
incoming_created=false
lock_acquired=false

cleanup() {
  exit_status="$?"
  if [[ "${incoming_created}" == "true" ]]; then
    chmod 0755 "${incoming_dir}" 2>/dev/null || true
    rm -f \
      "${incoming_dir}/index.html" \
      "${incoming_dir}/status-data.js"
    rmdir "${incoming_dir}" 2>/dev/null || true
  fi
  if [[ "${lock_acquired}" == "true" ]]; then
    rmdir "${lock_dir}" 2>/dev/null || true
  fi
  exit "${exit_status}"
}
trap cleanup EXIT HUP INT TERM

install -d -m 0755 "${web_root}"
if ! mkdir "${lock_dir}" 2>/dev/null; then
  echo "another status deployment or activation holds ${lock_dir}" >&2
  exit 1
fi
lock_acquired=true

if [[ -L "${web_root}/releases" ]]; then
  echo "releases directory must not be a symlink" >&2
  exit 1
fi
install -d -m 0755 "${web_root}/releases"
if [[ -L "${web_root}/releases" ]]; then
  echo "releases directory must not be a symlink" >&2
  exit 1
fi
if [[ -e "${release_dir}" || -L "${release_dir}" ]]; then
  echo "refusing to overwrite existing release: ${release_dir}" >&2
  exit 1
fi
if [[ -e "${incoming_dir}" || -L "${incoming_dir}" ]]; then
  echo "stale incoming path must be inspected and removed: ${incoming_dir}" >&2
  exit 1
fi
install -d -m 0755 "${incoming_dir}"
incoming_created=true
install -m 0644 "${source_dir}/index.html" "${incoming_dir}/index.html"
install -m 0644 \
  "${source_dir}/status-data.js" \
  "${incoming_dir}/status-data.js"

hash_command=()
if command -v sha256sum >/dev/null 2>&1; then
  hash_command=(sha256sum)
elif command -v shasum >/dev/null 2>&1; then
  hash_command=(shasum -a 256)
else
  echo "sha256sum or shasum is required" >&2
  exit 1
fi

for required in index.html status-data.js; do
  source_hash="$("${hash_command[@]}" "${source_dir}/${required}" | awk '{print $1}')"
  incoming_hash="$("${hash_command[@]}" "${incoming_dir}/${required}" | awk '{print $1}')"
  if [[ "${source_hash}" != "${incoming_hash}" ]]; then
    echo "release hash mismatch: ${required}" >&2
    exit 1
  fi
  echo "${required} ${incoming_hash}"
done

incoming_entries=()
while IFS= read -r -d '' entry; do
  incoming_entries+=("${entry}")
done < <(find "${incoming_dir}" -mindepth 1 -maxdepth 1 -print0)
if [[ "${#incoming_entries[@]}" != "2" ]]; then
  echo "incoming release must contain exactly two files" >&2
  exit 1
fi
for required in index.html status-data.js; do
  if [[ ! -f "${incoming_dir}/${required}" || -L "${incoming_dir}/${required}" ]]; then
    echo "incoming release is not a regular immutable payload: ${required}" >&2
    exit 1
  fi
done
chmod 0444 \
  "${incoming_dir}/index.html" \
  "${incoming_dir}/status-data.js"

if mv --version >/dev/null 2>&1; then
  mv -T "${incoming_dir}" "${release_dir}"
else
  if [[ -e "${release_dir}" || -L "${release_dir}" ]]; then
    echo "refusing to overwrite concurrently created release" >&2
    exit 1
  fi
  mv "${incoming_dir}" "${release_dir}"
fi
incoming_created=false
chmod 0555 "${release_dir}"

script_dir="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
export QUANT_OS_STATUS_DEPLOY_LOCK_HELD=1
"${script_dir}/activate_static_status.sh" "${release_sha}" "${web_root}"