#!/bin/sh
#
# Process (API) docs after a successful build on Travis (via ../.travis.yml).
#
# Updated/changed documentation for "master" is pushed to gh-pages.
# In case of pull requests or other branches, it will get added to a separate branch.
# In case of a pull request, a compare view comment will be posted.
#
# NOTE: stdout/stderr might/should be discarded to not leak sensitive information.

echo "Post-processing (API) documentation."
echo "TRAVIS_PULL_REQUEST: $TRAVIS_PULL_REQUEST"
echo "TRAVIS_BRANCH: $TRAVIS_BRANCH"

# GH_TOKEN won't be available for PRs from forks.
# (http://docs.travis-ci.com/user/pull-requests/#Security-Restrictions-when-testing-Pull-Requests).
if [ -z "GH_TOKEN" ]; then
  echo "No GH_TOKEN available. Skipping."
  exit
fi

# NOTE: DO NOT USE "set -x", or anything else that would reveal GH_TOKEN!
set -e
set +x

REPO_APIDOC="https://${GH_TOKEN}@github.com/awesomeWM/apidoc"
REPO_DIR="$PWD"

# Export these to not add "git config" calls to the long command.
export GIT_AUTHOR_NAME="awesome-robot on Travis CI"
export GIT_AUTHOR_EMAIL="awesome-robot@users.noreply.github.com"
export GIT_COMMITTER_NAME="$GIT_AUTHOR_NAME"
export GIT_COMMITTER_EMAIL="$GIT_AUTHOR_EMAIL"

git clone --quiet --branch gh-pages $REPO_APIDOC build/apidoc
cd build/apidoc

# This will re-use already existing branches (updated PR).
if [ "$TRAVIS_PULL_REQUEST" != false ]; then
  BRANCH="pr-$TRAVIS_PULL_REQUEST"
elif [ "$TRAVIS_BRANCH" != master ]; then
  # Use merge-base of master in branch name, to keep different branches with
  # the same name apart.
  BRANCH=$TRAVIS_BRANCH-$(cd ${REPO_DIR} \
    && git fetch --unshallow origin master \
    && git rev-parse --short $(git merge-base HEAD FETCH_HEAD || true) || true)
else
  BRANCH="gh-pages"
fi
if [ "$BRANCH" != "gh-pages" ]; then
  git checkout -b "$BRANCH" "origin/${BRANCH}" || git checkout -b "$BRANCH"
fi

# Use a temporary branch for the two commits, which allows for a better UI.
git checkout -b merged-update

# Create a patch without irrelevant changes (version / timestamp).
diff -Nur . ../doc -I "Last updated" -I "<strong>Release</strong>:" \
  -I "<h2>API documentation for awesome, a highly configurable X window manager (version .*)\.</h2>" \
  -x .git | patch -p1

git add --all .
if git diff --cached --exit-code --quiet; then
  echo "Documentation has not changed."
  exit
fi

# Commit the relevant changes.
OLD_REV="$(git rev-parse --short HEAD)"
COMMIT_MSG="Update docs for $AWESOME_VERSION via Travis

Last commit message:
$(cd $REPO_DIR && git log -1 --pretty=format:%s)

Build URL: https://travis-ci.org/awesomeWM/awesome/builds/${TRAVIS_BUILD_ID}"
git commit -m "[relevant] $COMMIT_MSG"
NEW_REV="$(git rev-parse --short HEAD)"

# Commit the irrelevant changes.
mv .git ../doc
cd ../doc
git add --all .
git commit -m "[boilerplate] $COMMIT_MSG"

# Reorder/swap commits, to have "relevant" after "boilerplate".
# This makes it show up earlier in the Github interface etc.
git tag _old
git reset --hard HEAD~2
git cherry-pick _old _old~1
git tag -d _old

git checkout "$BRANCH"
git merge --no-ff -m "$COMMIT_MSG" merged-update

git push --quiet origin "$BRANCH"

# Generate compare view links.
COMPARE_LINKS="Compare view: https://github.com/awesomeWM/apidoc/compare/${OLD_REV}...${NEW_REV}"
if [ "$BRANCH" != "gh-pages" ]; then
  COMPARE_LINKS="$COMPARE_LINKS\nComparison against master (gh-pages): https://github.com/awesomeWM/apidoc/compare/gh-pages...${NEW_REV}"
fi
echo "Compare links:\n$COMPARE_LINKS"

# Post a comment to the PR.
if [ "$TRAVIS_PULL_REQUEST" != false ]; then
  curl -H "Authorization: token $GH_TOKEN" \
    -d "{\"body\": \"Documentation has been updated for this PR:\n$COMPARE_LINKS\"}" \
    https://api.github.com/repos/awesomeWM/awesome/issues/${TRAVIS_PULL_REQUEST}/comments
fi