#!/usr/bin/env bash
# Verify dependencies for floppy-utils on Debian-based systems; optionally install via apt.
set -euo pipefail

INSTALL=0
QUIET=0

usage() {
    cat <<'EOF'
Usage: check-deps.sh [OPTIONS]

Check that base tools required by floppy-utils are available.
On Debian, Ubuntu, Raspberry Pi OS, and derivatives, missing packages can be
installed with apt when --install is passed.

Options:
  --install, -i   Install missing packages (requires apt and root/sudo)
  --quiet, -q     Only print errors and the install command
  -h, --help      Show this help

Examples:
  ./check-deps.sh
  ./check-deps.sh --install
  sudo ./check-deps.sh -i
EOF
}

while [[ $# -gt 0 ]]; do
    case "$1" in
        --install|-i) INSTALL=1; shift ;;
        --quiet|-q) QUIET=1; shift ;;
        -h|--help) usage; exit 0 ;;
        *) echo "check-deps.sh: unknown option: $1" >&2; usage >&2; exit 2 ;;
    esac
done

log() {
    if [[ "$QUIET" -eq 0 ]]; then
        echo "$@"
    fi
    return 0
}

warn() {
    echo "check-deps.sh: $*" >&2
    return 0
}

die() {
    warn "$*"
    exit 1
}

is_debian_like() {
    if [[ -f /etc/debian_version ]]; then
        return 0
    fi
    if [[ -f /etc/os-release ]]; then
        # shellcheck source=/dev/null
        source /etc/os-release
        case "${ID:-}:${ID_LIKE:-}" in
            debian:*|*debian*|ubuntu:*|*ubuntu*|raspbian:*|linuxmint:*|pop:*|elementary:*|kali:*|devuan:*)
                return 0
                ;;
        esac
    fi
    return 1
}

os_description() {
    if [[ -f /etc/os-release ]]; then
        # shellcheck source=/dev/null
        source /etc/os-release
        printf '%s %s\n' "${NAME:-Linux}" "${VERSION_ID:-}"
    elif [[ -f /etc/debian_version ]]; then
        printf 'Debian %s\n' "$(cat /etc/debian_version)"
    else
        echo "Unknown"
    fi
}

# command -> Debian package providing it
declare -A CMD_PKG=(
    [lsblk]=util-linux
    [blockdev]=util-linux
    [losetup]=util-linux
    [findmnt]=util-linux
    [fdisk]=util-linux
    [blkid]=util-linux
    [mount]=mount
    [umount]=mount
    [dd]=coreutils
    [readlink]=coreutils
    [mkfs.vfat]=dosfstools
    [sudo]=sudo
    [udisksctl]=udisks2
    [udevadm]=udev
    [eject]=eject
)

REQUIRED_CMDS=(
    lsblk blockdev losetup findmnt blkid mount umount dd readlink mkfs.vfat
)

RECOMMENDED_CMDS=(
    sudo udisksctl udevadm eject fdisk
)

have_cmd() {
    command -v "$1" >/dev/null 2>&1
}

packages_for_cmds() {
    local -A seen=()
    local cmd pkg
    for cmd in "$@"; do
        pkg="${CMD_PKG[$cmd]:-}"
        [[ -n "$pkg" && -z "${seen[$pkg]:-}" ]] || continue
        seen[$pkg]=1
        printf '%s\n' "$pkg"
    done
}

check_cmds() {
    local label="$1"
    local required="$2"
    shift 2
    local cmd
    local -a missing=()

    log "$label"
    for cmd in "$@"; do
        if have_cmd "$cmd"; then
            log "  OK   $cmd"
        else
            if [[ "$required" -eq 1 ]]; then
                log "  MISS $cmd (required)"
            else
                log "  MISS $cmd (recommended)"
            fi
            missing+=("$cmd")
        fi
    done
    log ""

    MISSING_RESULT=("${missing[@]}")
}

run_apt_install() {
    local -a packages=("$@")
    [[ ${#packages[@]} -gt 0 ]] || return 0

    if ! command -v apt-get >/dev/null 2>&1; then
        die "apt-get not found; install manually: ${packages[*]}"
    fi

    local -a apt_cmd=(apt-get)
    if [[ "$(id -u)" -ne 0 ]]; then
        command -v sudo >/dev/null 2>&1 || die "root or sudo required to install: ${packages[*]}"
        apt_cmd=(sudo apt-get)
    fi

    log "Installing: ${packages[*]}"
    "${apt_cmd[@]}" update -qq
    DEBIAN_FRONTEND=noninteractive "${apt_cmd[@]}" install -y --no-install-recommends "${packages[@]}"
}

main() {
    local -a missing_required=() missing_recommended=() packages=()
    local debian=0

    log "floppy-utils dependency check"
    log "OS: $(os_description)"

    if is_debian_like; then
        debian=1
        log "Debian-based system detected."
    else
        warn "Not a Debian-based system — will check commands only (no apt install)."
    fi
    log ""

    check_cmds "Required commands:" 1 "${REQUIRED_CMDS[@]}"
    missing_required=("${MISSING_RESULT[@]}")
    check_cmds "Recommended commands:" 0 "${RECOMMENDED_CMDS[@]}"
    missing_recommended=("${MISSING_RESULT[@]}")

    if [[ ${#missing_required[@]} -eq 0 && ${#missing_recommended[@]} -eq 0 ]]; then
        log "All required and recommended commands are available."
        exit 0
    fi

    if [[ ${#missing_required[@]} -gt 0 ]]; then
        log "Missing required: ${missing_required[*]}"
    fi
    if [[ ${#missing_recommended[@]} -gt 0 ]]; then
        log "Missing recommended: ${missing_recommended[*]}"
    fi

    mapfile -t packages < <(packages_for_cmds "${missing_required[@]}" "${missing_recommended[@]}")
    if [[ ${#packages[@]} -gt 0 ]]; then
        log "Debian packages: ${packages[*]}"
    fi

    if [[ "$INSTALL" -eq 1 ]]; then
        [[ "$debian" -eq 1 ]] || die "refusing --install on non-Debian system"
        run_apt_install "${packages[@]}"
        log ""
        log "Re-checking..."
        INSTALL=0
        main
        return
    fi

    if [[ "$debian" -eq 1 && ${#packages[@]} -gt 0 ]]; then
        log ""
        log "To install:"
        log "  sudo ./check-deps.sh --install"
        log "  # or: sudo apt-get install -y ${packages[*]}"
    fi

    if [[ ${#missing_required[@]} -gt 0 ]]; then
        die "required dependencies missing"
    fi

    warn "recommended tools missing — floppy-utils works with reduced functionality"
    exit 0
}

main