A bash script to render a graph with the number of releases per day

release_chart.sh

#!/usr/bin/env bash

###################################################################################
# usage example: bash local/release_chart.sh TypedDevs/bashunit --last 300
###################################################################################

set -euo pipefail

REPO=""
LIMIT_DAYS=0

main() {
  parse_args "$@"
  fetch_release_dates
  filter_by_days
  count_releases_per_day
  render_chart
}

parse_args() {
  if [[ $# -eq 0 ]]; then
    echo "Usage: $0 <owner/repo> [--last X]"
    exit 1
  fi

  REPO="$1"
  shift

  if [[ "${1:-}" == "--last" && -n "${2:-}" ]]; then
    LIMIT_DAYS="$2"
  fi
}

fetch_release_dates() {
  echo "Fetching data from GitHub for '$REPO'..."
  repo_name=$(gh api "/repos/$REPO" --jq '.full_name')

  all_dates=$(
    gh api -H "Accept: application/vnd.github+json" \
      "/repos/$REPO/releases" \
      --paginate \
    | jq -r '.[].published_at' \
    | cut -d'T' -f1 \
    | sort
  )
}

filter_by_days() {
  if [[ "$LIMIT_DAYS" -gt 0 ]]; then
    if date --version >/dev/null 2>&1; then
      cutoff_date=$(date -d "$LIMIT_DAYS days ago" +%F)
    else
      cutoff_date=$(date -v-"$LIMIT_DAYS"d +%F)
    fi
    release_dates=$(echo "$all_dates" | awk -v cutoff="$cutoff_date" '$0 >= cutoff')
  else
    release_dates="$all_dates"
  fi
}

count_releases_per_day() {
  counts=$(echo "$release_dates" | uniq -c | sort -k2)

  dates=()
  values=()
  max_count=0

  while read -r count date; do
    dates+=("$date")
    values+=("$count")
    (( count > max_count )) && max_count=$count
  done <<< "$counts"

  if [[ "${#dates[@]}" -eq 0 ]]; then
    echo "No releases found for '$repo_name' in the last $LIMIT_DAYS days."
    exit 0
  fi
}

render_chart() {
  echo ""
  echo "📦 Repo: $repo_name"
  [[ "$LIMIT_DAYS" -gt 0 ]] && echo "📅 Last $LIMIT_DAYS days" || echo "📅 All release history"

  find_peak_day
  echo "🏆 Peak day: ${dates[$peak_index]} (${values[$peak_index]} releases)"
  echo ""

  render_vertical_bars
  render_x_axis
}

find_peak_day() {
  peak_index=0
  for i in "${!values[@]}"; do
    if (( values[i] > values[peak_index] )); then
      peak_index=$i
    fi
  done
}

render_vertical_bars() {
  for (( level=max_count; level>=1; level-- )); do
    line=""
    for count in "${values[@]}"; do
      if (( count >= level )); then
        line+=" █ "
      else
        line+="   "
      fi
    done
    echo "$line"
  done
}

render_x_axis() {
  printf '%s\n' "$(printf '───'%.0s "${dates[@]}")"
  for date in "${dates[@]}"; do
    printf " %s" "${date:5:2}"  # MM
  done
  echo ""
  for date in "${dates[@]}"; do
    printf " %s" "${date:8:2}"  # DD
  done
  echo ""
}

main "$@"