# Copyright 2013 Gentoo Foundation
# Distributed under the terms of the GNU GPL version 2 or later

inherit config multilib

DESCRIPTION="Manage active Clang version"
MAINTAINER="eselect@gentoo.org"
VERSION="20130521"

B_PATH="${EROOT%/}/usr"
S_PATH="${EROOT%/}/usr/share/eselect-clang"

# Global Data
active_slot() {
    local link="${B_PATH}/bin/clang"
    if [[ -e "${link}" ]] ; then
        echo $(readlink -sf "${link}") | \
            sed -re 's#.*clang-([0-9]+(\.[0-9]+)?)$#\1#'
    fi
}

# Utility Functions
add_slot_suffix() {
    local file="$1"
    local slot="$2"
    local ext=""
    if [[ "${file}" =~ \. ]] ; then
        ext=".${file#*.}"
    fi
    local base="${file%%.*}"
    echo "${base}-${slot}${ext}"
}

### Linker Function ###
# Takes two arguments:
#   - Full path to versioned file (e.g. /usr/share/eselect-clang/slots/3.2/versioned)
#   - Slot to link (e.g. 3.2)
linker() {
    local versioned_file=$1
    local slot=$2
    if [[ -r ${versioned_file} ]] ; then
        local versioned=($(<"${versioned_file}"))

        local link_path
        for link_path in "${versioned[@]}" ; do
            link_path="${ROOT%/}/${link_path#/}"
            local link_dir=$(dirname "${link_path}")
            local link_name=$(basename "${link_path}")
            local rel_target=$(add_slot_suffix "${link_name}" "${slot}")
            local target="${link_dir}/${rel_target}"

            # For good measure, remove target before creating the symlink
            [[ -h ${link_path} ]] && rm -f "${link_path}"
            [[ -e ${link_path} ]] && \
                die -q "The target '${link_path}' still exists and could not be removed!"

            if [[ ! -e "${target}" ]] && [[ "${link_path}" == *man* ]] ; then
                local suffix=$(echo "${target}"* | sed 's/.*\.1//')
                if [[ "${suffix}" != "*" ]] ; then
                    rel_target="${rel_target}${suffix}"
                    link_path="${link_path}${suffix}"
                fi
            fi

            # Create relative links so that they work both here and inside the new
            # root if $ROOT is not "/".
            ln -s "${rel_target}" "${link_path}" || die -q "Unable to create link!"
        done
    fi
}

### Unlinker Function ###
# Takes one argument:
#   - Full path to versioned file (e.g. /usr/share/eselect-clang/slots/3.2/versioned)
unlinker() {
    local versioned_file=$1

    if [[ -r ${versioned_file} ]] ; then
        local versioned=($(<"${versioned_file}"))

        local link_path
        for link_path in "${versioned[@]}" ; do
            if [[ ! -e "${link_path}" ]] && [[ "${link_path}" == *man* ]] ; then
                local suffix=$(echo "${link_path}"* | sed 's/.*\.1//')
                if [[ "${suffix}" != "*" ]] ; then
                    link_path="${link_path}${suffix}"
                fi
            fi

            [[ -h "${ROOT%/}/${link_path}" ]] && \
                rm -f "${ROOT%/}/${link_path}"
            [[ -e "${ROOT%/}/${link_path}" ]] && \
                die -q "The target '${link_path}' still exists and could not be removed!"
        done
    fi
}

### Get Slots Function ###
# Find all available slots and return them.
get_slots() {
    echo $(find "${B_PATH}/bin/" -maxdepth 1 -type f \
        -regex '.*clang-[0-9][0-9]*\(\.[0-9][0-9]*\)?' | \
        sed -re 's#.*clang-([0-9]+(\.[0-9]+)?)$#\1#' | sort -n)
}

### List Action ###
describe_list() {
    echo "List available Clang slots."
}

do_list() {
    write_list_start "Available Clang slots"

    if $(is_output_mode brief) ; then
        echo $(get_slots)
    else
        local slot
        for slot in $(get_slots) ; do
            local ebuild=($(<"${S_PATH}/slots/${slot}/ebuild"))

            case "${slot}" in
                "$(active_slot)" ) write_kv_list_entry \
                    "$(highlight_marker ${slot})" "${ebuild}";;
                *                ) write_kv_list_entry \
                    "${slot}" "${ebuild}";;
            esac
        done

        [[ -z "${slot}" ]] && write_warning_msg "No slots available."
    fi
}

### Show Action ###
describe_show() {
    echo "Show which slot is currently active."
}

do_show() {
    local slot=$(active_slot)
    if [[ -n "${slot}" ]] ; then
        echo "${slot}"
    else
        echo "(none)"
    fi
}

### Set Action ###
describe_set() {
    echo "Create symbolic links for Clang libraries and applications."
}

do_set() {
    local slot=$1
    if [[ ! -e ${B_PATH}/bin/clang-${slot} ]] ; then
        die -q "Not a valid slot."
    fi

    echo -ne "Switching to Clang-${slot}... "

    # Remove the active links to start a fresh list
    local active=$(active_slot)
    if [[ -n "${active}" ]] ; then
        unlinker "${S_PATH}/slots/${active}/versioned"
    fi

    linker "${S_PATH}/slots/${slot}/versioned" ${slot}
    echo "done."
}

### Unset Action ###
describe_unset() {
    echo "Deselect the current or given slot."
}

do_unset() {
    local slot=${1:-$(active_slot)}
    if [[ -n ${slot} ]] && [[ ${slot} = $(active_slot) ]] ; then
        echo -n "Removing symlinks... "
        unlinker "${S_PATH}/slots/${slot}/versioned"
        echo "done."
        do_update
    else
        echo "Inactive slot selected. Nothing to do."
    fi
}

### Clear Action ###
describe_clear() {
    echo "Remove all active symlinks."
}

do_clear() {
    local slot=$(active_slot)
    if [[ -n ${slot} ]] ; then
        echo -n "Removing symlinks... "
        unlinker "${S_PATH}/slots/${slot}/versioned"
        echo "done."
    else
        echo "No slot selected. Nothing to do."
    fi
}

### Reset Action ###
describe_reset() {
    echo "Recreate symbolic links for currently active slot."
}

do_reset() {
    local slot=$(active_slot)
    [[ -z ${slot} ]] && die -q "No active slot to reset."
    do_clear
    do_set ${slot}
}

### Update Action ###
describe_update() {
    echo "Refreshes all symbolic links managed by this module"
}

do_update() {
    local slot=$(active_slot)

    local slots=($(get_slots))
    local index=${#slots[@]}

    # In case all slots have been unmerged
    if [[ ${index} -eq 0 ]] ; then
        if [[ -n ${slot} ]] ; then
            do_clear
        else
            write_warning_msg "No slots found! Nothing to do."
        fi
        return 0
    fi

    # Reset, otherwise set the highest slot available.
    if [[ -n ${slot} ]] && [[ ${slots[@]} =~ ${slot} ]] ; then
        do_set ${slot}
    else
        # best_version doesn't work here as pkg_postrm runs before the world
        # file is updated, thereby returning a false positive.
        do_set ${slots[$index-1]}
    fi

    do_action env update &> /dev/null
}