#!/usr/bin/env bash
# Pi-hole: A black hole for Internet advertisements
# (c) 2017 Pi-hole, LLC (https://pi-hole.net)
# Network-wide ad blocking via your own hardware.
#
# Switch Pi-hole subsystems to a different GitHub branch.
#
# This file is copyright under the latest version of the EUPL.
# Please see LICENSE file for your rights under this license.

readonly PI_HOLE_FILES_DIR="/etc/.pihole"
SKIP_INSTALL="true"
source "${PI_HOLE_FILES_DIR}/automated install/basic-install.sh"

# webInterfaceGitUrl set in basic-install.sh
# webInterfaceDir set in basic-install.sh
# piholeGitURL set in basic-install.sh
# is_repo() sourced from basic-install.sh
# setupVars set in basic-install.sh
# check_download_exists sourced from basic-install.sh

source "${setupVars}"

warning1() {
    echo "  Please note that changing branches or tags severely alters your Pi-hole subsystems"
    echo "  Features that work on the master branch, may not on a development branch"
    echo -e "  ${COL_LIGHT_RED}This feature is NOT supported unless a Pi-hole developer explicitly asks!${COL_NC}"
    read -r -p "  Have you read and understood this? [y/N] " response
    case "${response}" in
        [yY][eE][sS]|[yY])
            echo ""
            return 0
            ;;
        *)
            echo -e "\\n  ${INFO} Branch/Tag change has been canceled"
            return 1
            ;;
    esac
}

fully_fetch_repo() {
    # Add upstream branches/tags to shallow clone
    local directory="${1}"

    cd "${directory}" || return 1
    if is_repo "${directory}"; then
        git remote set-branches origin '*' || return 1
        git fetch --tags --quiet || return 1
    else
        return 1
    fi
    return 0
}

get_available_refs() {
    # Return available branches and tags
    local directory
    directory="${1}"
    local output

    cd "${directory}" || return 1
    # Get reachable remote branches and tags, but store STDERR as STDOUT variable
    output=$( { git ls-remote --heads --tags --quiet | cut -d'/' -f3- -; } 2>&1 )
    # echo status for calling function to capture
    echo "$output"
    return
}

fetch_checkout_pull_branch() {
    # Check out specified branch
    local directory
    directory="${1}"
    local branch
    branch="${2}"

    # Set the reference for the requested branch, fetch, check it put and pull it
    cd "${directory}" || return 1
    git remote set-branches origin "${branch}" || return 1
    git stash --all --quiet &> /dev/null || true
    git clean --quiet --force -d || true
    git fetch --quiet || return 1
    checkout_pull_ref "${directory}" "${branch}" || return 1
}

checkout_pull_ref() {
    # Check out specified branch/tag
    local directory
    directory="${1}"
    local ref
    ref="${2}"
    local oldref
    local ref_is_tag

    cd "${directory}" || return 1

    # Get current branch name.
    oldref="$(git symbolic-ref --quiet HEAD)"

    str="Switching to branch/tag: '${ref}' from '${oldref}'"
    printf "  %b %s" "${INFO}" "$str"

    # check if the ref is a branch or a tag on the remote repo
    if git show-ref -q --verify "refs/remotes/origin/$ref" 2>/dev/null; then
        ref_is_tag=false
    elif git show-ref -q --verify "refs/tags/$ref" 2>/dev/null; then
        ref_is_tag=true
    fi

    if [ "$ref_is_tag" = true ]; then
        # in case we want to checkout a tag we need explicitly create a new branch/reset the existing one
        git checkout -B "${ref}" "refs/tags/${ref}" --quiet || return 1
        printf "%b  %b %s\\n" "${OVER}" "${TICK}" "$str"
    else
        # checkout a branch, this also sets tracking branch
        git checkout "${ref}" --quiet || return 1
        printf "%b  %b %s\\n" "${OVER}" "${TICK}" "$str"
        git_pull=$(git pull --no-rebase || return 1)
        printf "  %b %s\\n" "${INFO}" "${git_pull}"
    fi

    # Data in the repositories is public anyway so we can make it readable by everyone (+r to keep executable permission if already set by git)
    chmod -R a+rX "${directory}"

    return 0
}

checkout() {
    local corerefs
    local webrefs

    # Check if FTL is installed - do this early on as FTL is a hard dependency for Pi-hole
    local funcOutput
    funcOutput=$(get_binary_name) #Store output of get_binary_name here
    local binary
    binary="pihole-FTL${funcOutput##*pihole-FTL}" #binary name will be the last line of the output of get_binary_name (it always begins with pihole-FTL)

    # Avoid globbing
    set -f

    # This is unlikely
    if ! is_repo "${PI_HOLE_FILES_DIR}" ; then
        echo -e "  ${COL_LIGHT_RED}Error: Core Pi-hole repo is missing from system!"
        echo -e "  Please re-run install script from https://github.com/pi-hole/pi-hole${COL_NC}"
        exit 1;
    fi
    if [[ "${INSTALL_WEB_INTERFACE}" == "true" ]]; then
        if ! is_repo "${webInterfaceDir}" ; then
            echo -e "  ${COL_LIGHT_RED}Error: Web Admin repo is missing from system!"
            echo -e "  Please re-run install script from https://github.com/pi-hole/pi-hole${COL_NC}"
            exit 1;
        fi
    fi

    if [[ -z "${1}" ]]; then
        echo -e "  ${COL_LIGHT_RED}Invalid option${COL_NC}"
        echo -e "  Try 'pihole checkout --help' for more information."
        exit 1
    fi

    if ! warning1 ; then
        exit 1
    fi

    if [[ "${1}" == "dev" ]] ; then
        # Shortcut to check out development branches
        echo -e "  ${INFO} Shortcut \"dev\" detected - checking out development / devel branches..."
        echo ""
        echo -e "  ${INFO} Pi-hole Core"
        fetch_checkout_pull_branch "${PI_HOLE_FILES_DIR}" "development" || { echo "  ${CROSS} Unable to pull Core development branch"; exit 1; }
        if [[ "${INSTALL_WEB_INTERFACE}" == "true" ]]; then
            echo ""
            echo -e "  ${INFO} Web interface"
            fetch_checkout_pull_branch "${webInterfaceDir}" "devel" || { echo "  ${CROSS} Unable to pull Web development branch"; exit 1; }
        fi
        #echo -e "  ${TICK} Pi-hole Core"

        local path
        path="development/${binary}"
        echo "development" > /etc/pihole/ftlbranch
        chmod 644 /etc/pihole/ftlbranch
    elif [[ "${1}" == "master" ]] ; then
        # Shortcut to check out master branches
        echo -e "  ${INFO} Shortcut \"master\" detected - checking out master branches..."
        echo -e "  ${INFO} Pi-hole core"
        fetch_checkout_pull_branch "${PI_HOLE_FILES_DIR}" "master" || { echo "  ${CROSS} Unable to pull Core master branch"; exit 1; }
        if [[ ${INSTALL_WEB_INTERFACE} == "true" ]]; then
            echo -e "  ${INFO} Web interface"
            fetch_checkout_pull_branch "${webInterfaceDir}" "master" || { echo "  ${CROSS} Unable to pull Web master branch"; exit 1; }
        fi
        #echo -e "  ${TICK} Web Interface"
        local path
        path="master/${binary}"
        echo "master" > /etc/pihole/ftlbranch
        chmod 644 /etc/pihole/ftlbranch
    elif [[ "${1}" == "core" ]] ; then
        str="Fetching branches/tags from ${piholeGitUrl}"
        echo -ne "  ${INFO} $str"
        if ! fully_fetch_repo "${PI_HOLE_FILES_DIR}" ; then
            echo -e "${OVER}  ${CROSS} $str"
            exit 1
        fi
        mapfile -t corerefs < <(get_available_refs "${PI_HOLE_FILES_DIR}")

        if [[ "${corerefs[*]}" == *"master"* ]]; then
            echo -e "${OVER}  ${TICK} $str"
            echo -e "  ${INFO} ${#corerefs[@]} branches/tags available for Pi-hole Core"
        else
            # Print STDERR output from get_available_refs
            echo -e "${OVER}  ${CROSS} $str\\n\\n${corerefs[*]}"
            exit 1
        fi

        echo ""
        # Have the user choose the branch/tag they want
        if ! (for e in "${corerefs[@]}"; do [[ "$e" == "${2}" ]] && exit 0; done); then
            echo -e "  ${INFO} Requested branch/tag \"${2}\" is not available"
            echo -e "  ${INFO} Available branches/tags for Core are:"
            for e in "${corerefs[@]}"; do echo "      - $e"; done
            exit 1
        fi
        checkout_pull_ref "${PI_HOLE_FILES_DIR}" "${2}"
    elif [[ "${1}" == "web" ]] && [[ "${INSTALL_WEB_INTERFACE}" == "true" ]] ; then
        str="Fetching branches/tags from ${webInterfaceGitUrl}"
        echo -ne "  ${INFO} $str"
        if ! fully_fetch_repo "${webInterfaceDir}" ; then
            echo -e "${OVER}  ${CROSS} $str"
            exit 1
        fi
        mapfile -t webrefs < <(get_available_refs "${webInterfaceDir}")

        if [[ "${webrefs[*]}" == *"master"* ]]; then
            echo -e "${OVER}  ${TICK} $str"
            echo -e "  ${INFO} ${#webrefs[@]} branches/tags available for Web Admin"
        else
            # Print STDERR output from get_available_refs
            echo -e "${OVER}  ${CROSS} $str\\n\\n${webrefs[*]}"
            exit 1
        fi

        echo ""
        # Have the user choose the branch/tags they want
        if ! (for e in "${webrefs[@]}"; do [[ "$e" == "${2}" ]] && exit 0; done); then
            echo -e "  ${INFO} Requested branch/tag \"${2}\" is not available"
            echo -e "  ${INFO} Available branches/tags for Web Admin are:"
            for e in "${webrefs[@]}"; do echo "      - $e"; done
            exit 1
        fi
        checkout_pull_ref "${webInterfaceDir}" "${2}"
        # Update local and remote versions via updatechecker
        /opt/pihole/updatecheck.sh
    elif [[ "${1}" == "ftl" ]] ; then
        local path
        local oldbranch
        path="${2}/${binary}"
        oldbranch="$(pihole-FTL -b)"

        if check_download_exists "$path"; then
            echo "  ${TICK} Branch ${2} exists"
            echo "${2}" > /etc/pihole/ftlbranch
            chmod 644 /etc/pihole/ftlbranch
            echo -e "  ${INFO} Switching to branch: \"${2}\" from \"${oldbranch}\""
            FTLinstall "${binary}"
            restart_service pihole-FTL
            enable_service pihole-FTL
            # Update local and remote versions via updatechecker
            /opt/pihole/updatecheck.sh
        else
            echo "  ${CROSS} Requested branch \"${2}\" is not available"
            ftlbranches=("$(git ls-remote https://github.com/pi-hole/ftl | grep 'heads' | sed 's/refs\/heads\///;s/ //g' | awk '{print $2}')")
            echo -e "  ${INFO} Available branches for FTL are:"
            for e in "${ftlbranches[@]}"; do echo "      - $e"; done
            exit 1
        fi

    else
        echo -e "  ${INFO} Requested option \"${1}\" is not available"
        exit 1
    fi

    # Force updating everything
    if [[  ! "${1}" == "web" && ! "${1}" == "ftl" ]]; then
        echo -e "  ${INFO} Running installer to upgrade your installation"
        if "${PI_HOLE_FILES_DIR}/automated install/basic-install.sh" --unattended; then
            exit 0
        else
            echo -e "  ${COL_LIGHT_RED} Error: Unable to complete update, please contact support${COL_NC}"
            exit 1
        fi
    fi
}