#!/usr/bin/env bash
set -e

# base variables
APP_NAME="$(basename "$0")"
BASE_PWD="$PWD"

# environment variables
# GITHUB_OAUTH_TOKEN    GitHub authentication token, see https://github.com/settings/tokens

# parameters
SOURCE_REPO_SLUG="$1"       # source GitHub repo (e.g. picocms/Pico)
SOURCE_REF="$2"             # source reference (either "[ref] @ [commit]" or "[ref]",
                            #                   [ref] can be e.g. heads/master or tags/v1.0.0)
SOURCE_DIR="$3"             # absolute source path
TARGET_REPO_SLUG="$4"       # target GitHub repo (e.g. picocms/Pico)
TARGET_BRANCH="$5"          # target branch (e.g. gh-pages)
TARGET_DIR="$6"             # relative target path

# print parameters
echo "Deploying phpDocs..."
printf 'SOURCE_REPO_SLUG="%s"\n' "$SOURCE_REPO_SLUG"
printf 'SOURCE_REF="%s"\n' "$SOURCE_REF"
printf 'SOURCE_DIR="%s"\n' "$SOURCE_DIR"
printf 'TARGET_REPO_SLUG="%s"\n' "$TARGET_REPO_SLUG"
printf 'TARGET_BRANCH="%s"\n' "$TARGET_BRANCH"
printf 'TARGET_DIR="%s"\n' "$TARGET_DIR"
echo

# evaluate source reference
if [[ "$SOURCE_REF" == *" @ "* ]]; then
    SOURCE_REF_TYPE="commit"
    SOURCE_REF_HEAD="${SOURCE_REF% @ *}"
    SOURCE_REF_COMMIT="${SOURCE_REF##* @ }"

    if ! git check-ref-format "$SOURCE_REF_HEAD" || ! git rev-parse --verify "$SOURCE_REF_COMMIT" > /dev/null; then
        echo "FATAL: $APP_NAME source reference '$SOURCE_REF' is invalid" >&2
        exit 1
    fi
elif git check-ref-format "$SOURCE_REF"; then
    SOURCE_REF_TYPE="ref"
else
    echo "FATAL: $APP_NAME source reference '$SOURCE_REF' is invalid" >&2
    exit 1
fi

# clone repo
printf 'Cloning repo...\n'
GIT_DIR="$SOURCE_DIR.git"
git clone --branch="$TARGET_BRANCH" "https://github.com/$TARGET_REPO_SLUG.git" "$GIT_DIR"

# setup git
cd "$GIT_DIR"
git config user.name "Travis CI"
git config user.email "travis-ci@picocms.org"

if [ -n "$GITHUB_OAUTH_TOKEN" ]; then
    git config credential.helper 'store --file=.git/credentials'
    (umask 077 && echo "https://GitHub:$GITHUB_OAUTH_TOKEN@github.com" > .git/credentials)
fi

# copy phpdoc
printf '\nCopying phpDocs...\n'
[ ! -d "$TARGET_DIR" ] || rm -rf "$TARGET_DIR"
[ "${SOURCE_DIR:0:1}" == "/" ] || SOURCE_DIR="$BASE_PWD/$SOURCE_DIR"
cp -R "$SOURCE_DIR" "$TARGET_DIR"

# commit changes
printf '\nCommiting changes...\n'
git add --all "$TARGET_DIR"
git commit --message="Update phpDocumentor class docs for $SOURCE_REF"

# very simple race condition protection for concurrent Travis builds
# this is no definite protection (race conditions are still possible during `git push`),
# but it should give a basic protection without disabling concurrent builds completely
if [ "$SOURCE_REF_TYPE" == "commit" ]; then
    # load branch data via GitHub APIv3
    printf '\nRetrieving latest commit...\n'
    LATEST_COMMIT_URL="https://api.github.com/repos/$SOURCE_REPO_SLUG/git/refs/$SOURCE_REF_HEAD"
    if [ -n "$GITHUB_OAUTH_TOKEN" ]; then
        LATEST_COMMIT_RESPONSE="$(wget -O- --header="Authorization: token $GITHUB_OAUTH_TOKEN" "$LATEST_COMMIT_URL" 2> /dev/null)"
    else
        LATEST_COMMIT_RESPONSE="$(wget -O- "$LATEST_COMMIT_URL" 2> /dev/null)"
    fi

    # evaluate JSON response
    LATEST_COMMIT="$(echo "$LATEST_COMMIT_RESPONSE" | php -r "
        \$json = json_decode(stream_get_contents(STDIN), true);
        if (\$json !== null) {
            if (isset(\$json['ref']) && (\$json['ref'] === 'refs/$SOURCE_REF_HEAD')) {
                if (isset(\$json['object']) && isset(\$json['object']['sha'])) {
                    echo \$json['object']['sha'];
                }
            }
        }
    ")"

    # compare source reference against the latest commit
    if [ "$LATEST_COMMIT" != "$SOURCE_REF_COMMIT" ]; then
        echo "WARNING: $APP_NAME source reference '$SOURCE_REF' doesn't match the latest commit '$LATEST_COMMIT'" >&2
        exit 0
    fi
fi

# push changes
printf '\nPushing changes...\n'
git push "https://github.com/$TARGET_REPO_SLUG.git" "$TARGET_BRANCH:$TARGET_BRANCH"

echo