changelog

#!/bin/bash

# generates a markdown-formatted changelog

set -euo pipefail

commit_url_base='https://github.com/segmentio/aws-okta/commit'

# generates a changelog between the current commit and the previous tag
changelog() {
  local repo_url prev current current_sha current_tag
  
  # if HEAD is a tag already, prev will the be second (non-prerelease) line
  if git describe --exact-match --tags > /dev/null 2>&1; then
    current_tag="$(git -c versionsort.suffix=- tag -l --sort=-v:refname | awk 'NR == 1 {print}')"
    prev="$(git -c versionsort.suffix=- tag -l --sort=-v:refname | awk 'NR > 1 {print}' | grep -v '-' | awk 'NR == 1 {print}')"
  else
    prev="$(git -c versionsort.suffix=- tag -l --sort=-v:refname | grep -v '-' | awk 'NR == 1 {print}')"
  fi
  current=HEAD

  # head -1 actually closes the pipe early, causing a SIGPIPE
  set +o pipefail
  current_sha="$(git log --pretty=format:%h | head -1)"
  set -o pipefail

  if [[ -z "${current_tag:-}" ]]; then
    echo "# ${current_sha} vs ${prev}"
  else
    echo "# ${current_tag} vs ${prev}"
  fi


  declare -a feat pipeline fix meta misc lines
  local lines
  local lines_s
  local feat=()
  local pipeline=()
  local fix=()
  local meta=()
  local misc=()
  oldifs=$IFS
  lines_s=$(git log --pretty=format:"* [\`%h\`](${commit_url_base}/%H) %s (%an)"   "${prev}..${current}" -- .)
  local IFS=$'\n'
  lines=($lines_s)
  for line in "${lines[@]:-}"; do
    if echo $line | grep -E ') feat[^:]*:' > /dev/null 2>&1; then
      feat+=("$line")
    elif echo $line | grep -E ') pipeline[^:]*:' > /dev/null 2>&1; then
      pipeline+=("$line")
    elif echo $line | grep -E ') fix[^:]*:' > /dev/null 2>&1; then
      fix+=("$line")
    elif echo $line | grep -E ') meta[^:]*:' > /dev/null 2>&1; then
      meta+=("$line")
    else
      misc+=("$line")
    fi
  done 

  if [[ "${#feat[@]}" -gt 0 ]]; then
    echo "# Features"
    for l in "${feat[@]}"; do
      echo "$l"
    done
  fi

  if [[ "${#fix[@]}" -gt 0 ]]; then
    echo "# Fixes"
    for l in "${fix[@]}"; do
      echo "$l"
    done
  fi

  if [[ "${#pipeline[@]}" -gt 0 ]]; then
    echo "# Pipeline"
    for l in "${pipeline[@]}"; do
      echo "$l"
    done
  fi

  if [[ "${#meta[@]}" -gt 0 ]]; then
    echo "# Meta"
    for l in "${meta[@]}"; do
      echo "$l"
    done
  fi

  if [[ "${#misc[@]}" -gt 0 ]]; then
    echo "# Misc"
    for l in "${misc[@]}"; do
      echo "$l"
    done
  fi
}

changelog