#!/usr/bin/env bash
#
# Usage: affected-projects.sh <state-dir> [base-commit]
#
# Runs the checkAffected task of every project for the changes between the base commit and HEAD
# and writes the result to $GITHUB_OUTPUT:
#   projects - space separated paths of the affected projects
#   tasks    - space separated Gradle tasks to run (empty if nothing is affected)
#
# The projects exchange files with this script through the state directory. If it contains
# previous-dependency-versions (deploys only), projects whose resolved dependency versions changed are
# affected as well and the collected dependency-versions, deploy-artifacts and deploy-commands of all
# projects are written to it. Without a known base commit everything is affected.

set -euo pipefail
shopt -s nullglob

mkdir -p "$1"
state="$(realpath "$1")"
base="${2:-}"

deploy=false
if [[ -f "${state}/previous-dependency-versions" ]]; then
  deploy=true
fi

# Whether the diff of settings.gradle.kts only touches library versions of the version catalog
catalog_only() {
  ! git diff -U0 --no-renames "$base" HEAD -- settings.gradle.kts \
    | grep -E '^[+-]' \
    | grep -vE '^(\+\+\+|---) ' \
    | grep -qvE '^[+-][[:space:]]*(library\("|val [A-Za-z]+Version = "|$)'
}

# All lines the projects wrote for the given kind
collect() {
  local files=("${state}/projects/$1"/*)
  if (( ${#files[@]} )); then
    sort "${files[@]}"
  fi
}

rm -f "${state}/changed-files"

if [[ -z "$base" ]]; then
  echo "No base commit, everything is affected"
elif ! git cat-file -e "${base}^{commit}" 2>/dev/null; then
  echo "Base commit ${base} is unknown, everything is affected"
else
  echo "Changed files since ${base}:"
  git diff --name-only --no-renames "$base" HEAD | tee "${state}/changed-files"

  # Library version changes are detected through the resolved dependency versions of the projects using them
  if [[ "$deploy" == "true" ]] && grep -qx 'settings.gradle.kts' "${state}/changed-files" && catalog_only; then
    echo "settings.gradle.kts only changed library versions, relying on the dependency versions"
    grep -vx 'settings.gradle.kts' "${state}/changed-files" > "${state}/changed-files.filtered" || true
    mv "${state}/changed-files.filtered" "${state}/changed-files"
  fi
fi

args=(-q --no-daemon checkAffected -PciDir="$state")
if [[ "$deploy" == "true" ]]; then
  args+=(deployInfo --refresh-dependencies)
fi
./gradlew "${args[@]}"

if [[ "$deploy" == "true" ]]; then
  collect dependency-versions > "${state}/dependency-versions"
  collect deploy-artifacts > "${state}/deploy-artifacts"
  collect deploy-commands > "${state}/deploy-commands"
fi

projects="$(collect affected | cut -d ' ' -f 1 | sort -u | paste -sd ' ' -)"
tasks="$(collect affected | cut -d ' ' -f 1 | sort -u | sed 's/$/:build/' | paste -sd ' ' -)"

echo "projects=${projects}"
echo "tasks=${tasks}"

{
  echo "projects=${projects}"
  echo "tasks=${tasks}"
} >> "$GITHUB_OUTPUT"