#!/usr/bin/env bash
# Usage: ./scripts/fetch-year.sh YEAR [--reverse]
# Fetches sequentially; prints JSON responses to stdout and errors to stderr.
set -euo pipefail

reverse=false
year=
for arg in "$@"; do
  case "$arg" in
    --reverse) reverse=true ;;
    *)
      if [[ -n $year ]]; then
        echo "Usage: $0 YEAR [--reverse]" >&2
        exit 1
      fi
      year=$arg
      ;;
  esac
done
if [[ -z $year ]]; then
  echo "Usage: $0 YEAR [--reverse]" >&2
  exit 1
fi
if [[ ! $year =~ ^[0-9]{4}$ || $year == 0000 ]]; then
  echo "YEAR must be a four-digit year from 0001 to 9999." >&2
  exit 1
fi

year_number=$((10#$year))
days_in_month=(31 28 31 30 31 30 31 31 30 31 30 31)
if (( year_number % 400 == 0 || (year_number % 4 == 0 && year_number % 100 != 0) )); then
  days_in_month[1]=29
fi

# Reuse a reachable service, or keep a port-forward alive while fetching.
service_ready() {
  curl --fail --silent --output /dev/null --connect-timeout 1 --max-time 2 \
    'http://localhost:4101/api/health'
}

forward_pid=
cleanup() {
  if [[ -n $forward_pid ]]; then
    kill "$forward_pid" 2>/dev/null || true
    wait "$forward_pid" 2>/dev/null || true
    forward_pid=
  fi
}
trap cleanup EXIT
trap 'exit 130' INT
trap 'exit 143' TERM

wait_for_pod() {
  local selector
  # Use the service's selector rather than assuming a particular pod label.
  if ! selector=$(kubectl -n sejs get svc btcdata --request-timeout=10s \
    -o go-template='{{range $key, $value := .spec.selector}}{{$key}}={{$value}},{{end}}'); then
    return 1
  fi
  selector=${selector%,}
  if [[ -z $selector ]]; then
    echo "Service sejs/btcdata has no pod selector." >&2
    return 1
  fi
  echo "Waiting up to 5 minutes for btcdata pods to become Ready..." >&2
  kubectl -n sejs wait --for=condition=Ready pod --selector="$selector" \
    --timeout=300s --request-timeout=310s >&2
}

start_forward() {
  local attempt
  cleanup
  if ! command -v kubectl >/dev/null 2>&1; then
    echo "Service unavailable on localhost:4101 and kubectl is not installed." >&2
    return 1
  fi
  if ! wait_for_pod; then
    echo "btcdata pod readiness check failed; not opening a tunnel." >&2
    return 1
  fi
  echo "Starting kubectl port-forward for sejs/btcdata..." >&2
  kubectl -n sejs port-forward svc/btcdata 4101:4101 >&2 &
  forward_pid=$!

  for (( attempt = 0; attempt < 30; attempt++ )); do
    if ! kill -0 "$forward_pid" 2>/dev/null; then
      echo "Port-forward exited before the service became ready." >&2
      cleanup
      return 1
    fi
    if service_ready; then
      return 0
    fi
    sleep 1
  done
  echo "Timed out waiting for the service on localhost:4101." >&2
  cleanup
  return 1
}

ensure_service() {
  local retry
  if service_ready; then
    return 0
  fi
  for (( retry = 1; retry <= 3; retry++ )); do
    echo "Recovering port-forward (attempt $retry/3)..." >&2
    if start_forward; then
      return 0
    fi
    if (( retry < 3 )); then
      sleep 2
    fi
  done
  echo "Unable to restore the service on localhost:4101." >&2
  return 1
}

fetch_date() {
  curl --fail --silent --show-error --connect-timeout 5 -X GET \
    "http://localhost:4101/api/price/day/$1" \
    -H "accept: application/json" --write-out '\n'
}

ensure_service || exit 1

# Generate dates without relying on platform-specific date command options.
status=0
for (( month_index = 0; month_index < 12; month_index++ )); do
  month=$((month_index + 1))
  if [[ $reverse == true ]]; then
    month=$((12 - month_index))
  fi
  days=${days_in_month[month - 1]}
  for (( day_index = 0; day_index < days; day_index++ )); do
    day=$((day_index + 1))
    if [[ $reverse == true ]]; then
      day=$((days - day_index))
    fi
    printf -v date '%s-%02d-%02d' "$year" "$month" "$day"
    if ! fetch_date "$date"; then
      if ! service_ready; then
        ensure_service || exit 1
        echo "Retrying $date after tunnel recovery..." >&2
        if fetch_date "$date"; then
          continue
        fi
      fi
      echo "Failed to fetch $date" >&2
      status=1
    fi
  done
done
exit "$status"