#!/usr/bin/env bash

# This script will generate the next release using changeset.
# However, since changeset has its own semvar versioning system
# and we have our custom tags, this script rewrites the CHANGELOG.md
# with each tag as its header and group respective changeset that has
# the tag under it.
#
# The workflow is here:
# https://github.com/smartcontractkit/chainlink/actions/workflows/changesets-preview-pr.yml

set -euo pipefail

if [[ -z "${GITHUB_OUTPUT:-}" ]]; then
  echo "GITHUB_OUTPUT environment variable is not set."
  exit 1
fi

create_changesets_json() {
  echo "[[]]" > changesets.json
}

create_tags_json() {
  json="{}"
  for tag in "${tags_list[@]}"; do
    tag=${tag:1}
    json=$(jq --arg k "$tag" '.[$k] = []' <<< "$json")
  done
  echo "$json" > tags.json
}

append_changeset_content() {
  if [[ $1 != "" ]]; then
    jq --argjson idx "$changesets_index" --arg str "$1" \
     '.[$idx] += [$str]' changesets.json > tmp.json && mv tmp.json changesets.json
  fi
}

append_changelog_content() {
  for tag in "${tags_list[@]}"; do
    tag=${tag:1}
    array_length=$(jq -r --arg key "$tag" '.[$key] | length' tags.json)
    if [[ $array_length -eq 0 ]]; then
      continue
    fi
    changesets=$(jq -r --arg key "$tag" '.[$key] | join("\n\n")' tags.json)
    read -d '' changelog_content <<EOF || true
${changelog_content}

## ${tag}

${changesets}
EOF
  done
}

set_pr_body() {
  # GitHub Issues/PRs messages have a max size limit on the message body payload.
  # This is the error: `body is too long (maximum is 65536 characters)`.
  max_pr_desc_char_length=65000
  read -d '' pr_header <<EOF || true
This PR is a preview of the changes that will be included in the next release. Please do not merge this PR.
---
EOF
  if [[ ${#changelog_content} -gt $max_pr_desc_char_length ]]; then
    read -d '' pr_body <<EOF || true
${pr_header}
The changelog content is too long for the PR description. Please view the full changelog in the [CHANGELOG.md](https://github.com/smartcontractkit/chainlink/blob/changesets/release-preview/CHANGELOG.md)
EOF
  else
    read -d '' pr_body <<EOF || true
${pr_header}
${changelog_content}
EOF
  fi
  # for multi-line output
  echo "pr_body<<EOF" >> $GITHUB_OUTPUT
  echo "${pr_body}" >> $GITHUB_OUTPUT
  echo "EOF" >> $GITHUB_OUTPUT
}

set_new_changelog_content() {
  read -d '' new_changelog <<EOF || true
${changelog_content}
${current_changelog}
EOF

echo "$new_changelog" > CHANGELOG.md
}

# checks for tags in each changeset entry and append to tags.json
match_tags() {
  changesets_with_index=$(jq -r 'to_entries | .[] | "\(.key) \(.value | join(" "))"' changesets.json)

  echo "$changesets_with_index" | while IFS= read -r line; do
    index="${line%% *}"
    changeset_content="${line#* }"
    changeset_formatted=$(jq -r --argjson idx "$index" '.[$idx] | join("\n")' changesets.json)
    found_tag=""
    for tag in "${tags_list[@]}"; do
      if [[ "$changeset_content" =~ $tag ]]; then
        found_tag=${tag:1}
        jq --arg key "$found_tag" --arg val "$changeset_formatted" \
         '.[$key] += [$val]' tags.json > tmp.json && mv tmp.json tags.json
      fi
    done
    if [[ $found_tag == "" ]] && [[ ! -z $changeset_content ]]; then
      found_tag="untagged"
      jq --arg key "$found_tag" --arg val "$changeset_formatted" \
       '.[$key] += [$val]' tags.json > tmp.json && mv tmp.json tags.json
    fi
  done
}

cleanup() {
  rm -f CHANGELOG.md.tmp
  rm -f changesets.json
  rm -f tags.json
}

### SCRIPT STARTS HERE ###

tail -n +2 CHANGELOG.md > CHANGELOG.md.tmp

pnpm changeset version

version=$(jq -r '.version' package.json)
echo "version=$version" >> $GITHUB_OUTPUT

read -d '' changelog_content <<EOF || true
# Changelog Chainlink Core

## ${version} - PREVIEW

EOF

current_changelog=$(cat CHANGELOG.md.tmp)
is_current_version=false
changesets_index=0
tags_list=( "#nops" "#added" "#changed" "#removed" "#updated" "#deprecation_notice" "#breaking_change" "#db_update" "#wip" "#bugfix" "#internal" "#untagged")

create_changesets_json
create_tags_json

while IFS= read -r line; do
  # break when hits the next version
  if [[ $line == "## "* ]] && [[ $is_current_version = true ]]; then
    break
  fi

  # look for the latest version
  if [[ $line == "## "* ]]; then
    is_current_version=true
  fi

  if [[ $is_current_version = true ]]; then
    # saving each changeset to changeset.json
    # check for start of changeset entry as it could be multi-lined entry
    if [[ $line == "- ["* ]]; then
      changesets_index=$((changesets_index+1))
      append_changeset_content "$line"
    elif [[ $line != "##"* ]]; then
      append_changeset_content "$line"
    fi
  fi
done < CHANGELOG.md

match_tags
append_changelog_content
set_pr_body
set_new_changelog_content
cleanup