#!/usr/bin/env nix
# vim: set filetype=bash:
#!nix shell .#changelog-d --command bash

set -euo pipefail

# --- CONFIGURATION ---

# This does double duty for
# - including rl-next
# - marking where to insert new links (right after)
SUMMARY_MARKER_LINE='{{#include ./SUMMARY-rl-next.md}}'

# --- LIB ---

log() {
  echo 1>&2 "release-notes:" "$@"
}
logcmd() {
  local cmd="$1"
  shift
  logcmd2 "$cmd" "${*@Q}" "$cmd" "$@"
}
logcmd2() {
  local fakecmd="$1"
  local fakeargs="$2"
  shift
  shift
  printf 1>&2 "release-notes: \033[34;1m$fakecmd\033[0m "
  echo "$fakeargs" 1>&2
  "$@"
}
die() {
  # ANSI red
  printf 1>&2 "release-notes: \033[31;1merror:\033[0m"
  echo 1>&2 "" "$@"
  exit 1
}
confirm() {
  local answer
  echo 1>&2 "$@" "[y/n]"
  read -r answer
  case "$answer" in
    y|Y|yes|Yes|YES)
      return 0
      ;;
    n|N|no|No|NO)
      return 1
      ;;
    *)
      echo 1>&2 "please answer y or n"
      confirm "$@"
      ;;
  esac
}
report_done() {
  logcmd2 "git" "show" git -c pager.show=false show
  printf 1>&2 "release-notes: \033[32;1mdone\033[0m\n"
}

# --- PARSE ARGS ---

if [[ $# -gt 0 ]]; then
  die "Release notes takes no arguments, but make sure to set VERSION."
fi

# --- CHECKS ---

if [[ ! -e flake.nix ]] || [[ ! -e .git ]]; then
  die "must run in repo root"
  exit 1
fi

# repo must be clean
if ! git diff --quiet; then
  die "repo is dirty, please commit or stash changes"
fi

if ! git diff --quiet --cached; then
  die "repo has staged changes, please commit or stash them"
fi

if ! grep "$SUMMARY_MARKER_LINE" doc/manual/source/SUMMARY.md.in >/dev/null; then
  # would have been nice to catch this early, but won't be worth the extra infra
  die "SUMMARY.md.in is missing the marker line '$SUMMARY_MARKER_LINE', which would be used for inserting a new release notes page. Please fix the script."
fi

if [[ ! -n "${VERSION:-}" ]]; then
  die "please set the VERSION environment variable before invoking this script"
  exit 1
fi

# version_major_minor:      MAJOR.MINOR
# version_full:             MAJOR.MINOR.PATCH
# IS_PATCH:                 true if this is a patch release; append instead of create
if grep -E '^[0-9]+\.[0-9]+$' <<< "$VERSION" >/dev/null; then
  log 'is minor'
  IS_PATCH=false
  version_full="$VERSION.0"
  version_major_minor="$VERSION"
elif grep -E '^[0-9]+\.[0-9]+\.0$' <<< "$VERSION" >/dev/null; then
  log 'is minor (.0)'
  IS_PATCH=false
  version_full="$VERSION"
  version_major_minor="$(echo "$VERSION" | sed -e 's/\.0$//')"
elif grep -E '^[0-9]+\.[0-9]+\.[0-9]+$' <<< "$VERSION" >/dev/null; then
  log 'is patch'
  IS_PATCH=true
  version_full="$VERSION"
  version_major_minor="$(echo "$VERSION" | sed -e 's/\.[0-9]*$//')"
else
  die "VERSION must be MAJOR.MINOR[.PATCH], where each is a number, e.g. 2.20 or 2.20.1 (VERSION was set to $VERSION)"
fi

unset VERSION

log "version_major_minor=$version_major_minor"
log "version_full=$version_full"
log "IS_PATCH=$IS_PATCH"

basename=rl-${version_major_minor}.md
file=doc/manual/source/release-notes/$basename

if ! $IS_PATCH; then
  if [[ -e $file ]]; then
    die "release notes file $file already exists. If you'd like to make a minor release, pass a patch version, e.g. 2.20.1"
  fi
fi

# --- DEFAULTS ---

if [[ ! -n "${DATE:-}" ]]; then
  DATE="$(date +%Y-%m-%d)"
  log "DATE not set, using $DATE"
fi

case "$DATE" in
  [0-9][0-9][0-9][0-9]-[0-9][0-9]-[0-9][0-9])
    ;;
  *)
    die "DATE must be YYYY-MM-DD, e.g. 2021-12-31 (DATE was set to $DATE)"
    ;;
esac

# --- DO THE WORK ---

# menu
title="Release $version_major_minor ($DATE)"
# section on page
section_title="Release $version_full ($DATE)"

(
  # TODO add minor number, and append?
  echo "# $section_title"
  echo
  changelog-d doc/manual/rl-next | sed -e 's/ *$//'

  if ! $IS_PATCH; then
    echo
    echo "# Contributors"
    echo
    VERSION=$version_full ./maintainers/release-credits
  fi
) | tee -a $file

log "Wrote $file"

if ! $IS_PATCH; then
  NEW_SUMMARY_LINE="  - [$title](release-notes/$basename)"

  # find the marker line, insert new link after it
  escaped_marker="$(echo "$SUMMARY_MARKER_LINE" | sed -e 's/\//\\\//g' -e 's/ /\\ /g')"
  escaped_line="$(echo "$NEW_SUMMARY_LINE" | sed -e 's/\//\\\//g' -e 's/ /\\ /g')"
  logcmd sed -i -e "/$escaped_marker/a $escaped_line" doc/manual/source/SUMMARY.md.in
fi

for f in doc/manual/rl-next/*.md; do
  if [[ config != "$(basename $f)" ]]; then
    logcmd git rm $f
  fi
done

logcmd git add $file doc/manual/source/SUMMARY.md.in
logcmd git status
logcmd git commit -m "release notes: $version_full"

report_done
