#!/bin/bash
#
# sogrep - find shared library links in an Arch Linux repository.
#
# Copyright (c) 2019 by Eli Schwartz <eschwartz@archlinux.org>
#
# SPDX-License-Identifier: GPL-3.0-or-later

m4_include(lib/common.sh)

# globals
: ${SOLINKS_MIRROR:="https://mirror.pkgbuild.com"}
: ${SOCACHE_DIR:="${XDG_CACHE_HOME:-${HOME}/.cache}/sogrep"}

m4_include(lib/valid-repos.sh)
arches=('x86_64')

# options
REFRESH=0
VERBOSE=0

source /usr/share/makepkg/util/parseopts.sh
source /usr/share/makepkg/util/util.sh

recache() {
    local repo arch verbosity=-s

    (( VERBOSE )) && verbosity=--progress-bar

    for repo in "${_repos[@]}"; do
        for arch in "${arches[@]}"; do
            # delete extracted tarballs from previous sogrep versions
            rm -rf "${SOCACHE_DIR}/${arch}/${repo}"

            # fetch repo links database if newer than our cached copy
            local dbpath=${SOCACHE_DIR}/${arch}/${repo}.links.tar.gz
            mkdir -p "${dbpath%/*}"
            (( VERBOSE )) && echo "Fetching ${repo}.links.tar.gz..."
            curl -LR "${verbosity}" -o "${dbpath}" -z "${dbpath}" \
                "${SOLINKS_MIRROR}/${repo}/os/${arch}/${repo}.links.tar.gz"
        done
    done
}

is_outdated_cache() {
    local repo arch

    # links databases are generated at about the same time every day; we should
    # attempt to check for new database files if any of them are over a day old

    for repo in "${_repos[@]}"; do
        for arch in "${arches[@]}"; do
            local dbpath=${SOCACHE_DIR}/${arch}/${repo}.links.tar.gz
            if [[ ! -f ${dbpath} ]] || [[ $(find "${dbpath}" -mtime +0) ]]; then
                return 0
            fi
        done
    done

    return 1
}

search() {
    local repo=$1 arch lib=$2 srepos=("${_repos[@]}")

    if [[ $repo != all ]]; then
        if ! in_array "${repo}" "${_repos[@]}"; then
            echo "${BASH_SOURCE[0]##*/}: unrecognized repo '$repo'"
            echo "Try '${BASH_SOURCE[0]##*/} --help' for more information."
            exit 1
        fi
        srepos=("${repo}")
    fi

    setup_workdir

    for arch in "${arches[@]}"; do
        for repo in "${srepos[@]}"; do
            local prefix=
            (( VERBOSE && ${#srepos[@]} > 1 )) && prefix=${repo}/
            local db=${SOCACHE_DIR}/${arch}/${repo}.links.tar.gz
            if [[ -f ${db} ]]; then
                local extracted=${WORKDIR}/${arch}/${repo}
                mkdir -p "${extracted}"
                bsdtar -C "${extracted}" -xf "${db}"
                while read -rd '' pkg; do
                    read -r match
                    pkg=${pkg#${extracted}/}
                    pkg="${prefix}${pkg%-*-*/links}"

                    if (( VERBOSE )); then
                        printf '%-35s %s\n' "${pkg}" "${match}"
                    else
                        printf '%s\n' "${pkg}"
                    fi
                done < <(grep -rZ "${lib}" "${extracted}") | sort -u
            fi
        done
    done | resort
}

usage() {
    cat <<- _EOF_
		Usage: ${BASH_SOURCE[0]##*/} [OPTIONS] REPO LIBNAME

		Check the soname links database for Arch Linux repositories containing
		packages linked to a given shared library. If the repository specified
		is "all", then all repositories will be searched, otherwise only the
		named repository will be searched.

		If the links database does not exist, it will be downloaded first.

		OPTIONS
		    -v, --verbose   Show matched links in addition to pkgname
		    -r, --refresh   Refresh the links databases
		    -h, --help      Show this help text
_EOF_
}

# utility function to resort with multiple repos + no-verbose
resort() { sort -u; }

if (( $# == 0 )); then
    echo "error: No arguments passed."
    echo "Try '${BASH_SOURCE[0]##*/} --help' for more information."
    exit 1
fi
OPT_SHORT='vrh'
OPT_LONG=('verbose' 'refresh' 'help')
if ! parseopts "$OPT_SHORT" "${OPT_LONG[@]}" -- "$@"; then
    exit 1
fi
set  -- "${OPTRET[@]}"

while :; do
    case $1 in
        -v|--verbose)
            resort() { cat; }
            VERBOSE=1
            ;;
        -r|--refresh)
            REFRESH=1
            ;;
        -h|--help)
            usage
            exit 0
            ;;
        --)
            shift; break
            ;;
    esac
    shift
done

if ! (( ( REFRESH && $# == 0 ) || $# == 2 )); then
    echo "error: Incorrect number of arguments passed."
    echo "Try '${BASH_SOURCE[0]##*/} --help' for more information."
    exit 1
fi

# trigger a refresh if requested explicitly or the cached dbs might be outdated
if (( REFRESH )) || [[ ! -d ${SOCACHE_DIR} ]] || is_outdated_cache; then
    recache
    (( $# == 2 )) || exit 0
fi

search "$@"