#!/usr/bin/env bash
set -Eeuo pipefail

SCRIPT_NAME="$(basename "${BASH_SOURCE[0]}")"
readonly SCRIPT_NAME

readonly SERVER_RESPONSE_FILE="/run/tuxflotte/server/response.json"
readonly RUNTIME_DIR="/run/tuxflotte/assignment"
readonly PROFILE_FILE="${RUNTIME_DIR}/profile.json"

log() {
    printf '[%s] %s\n' "${SCRIPT_NAME}" "$*"
}

fatal() {
    printf '[%s] FEHLER: %s\n' "${SCRIPT_NAME}" "$*" >&2
    exit 1
}

require_root() {
    if [[ "${EUID}" -ne 0 ]]; then
        fatal "Das Profilauswahlmodul muss als root ausgeführt werden."
    fi
}

prepare_runtime() {
    install -d -m 0700 "${RUNTIME_DIR}"
    rm -f -- "${PROFILE_FILE}"
}

validate_server_response() {
    [[ -r "${SERVER_RESPONSE_FILE}" ]] ||
        fatal "Serverantwort nicht gefunden: ${SERVER_RESPONSE_FILE}"

    jq --exit-status . "${SERVER_RESPONSE_FILE}" >/dev/null ||
        fatal "Serverantwort enthält kein gültiges JSON."

    jq --exit-status '
        .success == true
        and (.profiles | type == "array")
        and (.profiles | length > 0)
    ' "${SERVER_RESPONSE_FILE}" >/dev/null ||
        fatal "Serverantwort enthält keine auswählbaren Profile."
}

show_profiles() {
    local index=1
    local profile

    log "Verfügbare Provisioning-Profile:"

    while IFS= read -r profile; do
        printf '\n'
        printf '  %d) %s\n' \
            "${index}" \
            "$(jq -r '.label' <<<"${profile}")"

        printf '     Distribution: %s %s\n' \
            "$(jq -r '.distribution' <<<"${profile}")" \
            "$(jq -r '.version' <<<"${profile}")"

        printf '     %s\n' \
            "$(jq -r '.description // ""' <<<"${profile}")"

        ((index += 1))
    done < <(jq -c '.profiles[]' "${SERVER_RESPONSE_FILE}")
}

select_profile() {
    local profile_count
    local selection

    profile_count="$(jq '.profiles | length' "${SERVER_RESPONSE_FILE}")"

    while true; do
        printf '\n'
        read -r -p "Profil auswählen [1-${profile_count}]: " selection

        if [[ "${selection}" =~ ^[0-9]+$ ]] &&
            ((selection >= 1 && selection <= profile_count)); then
            break
        fi

        log "Ungültige Auswahl."
    done

    jq \
        --argjson index "$((selection - 1))" \
        '{
            schema_version: 1,
            profile: .profiles[$index]
        }' \
        "${SERVER_RESPONSE_FILE}" >"${PROFILE_FILE}"

    chmod 0600 "${PROFILE_FILE}"

    jq --exit-status '
        .schema_version == 1
        and (.profile | type == "object")
        and (.profile.id | type == "string")
        and (.profile.id | length > 0)
    ' "${PROFILE_FILE}" >/dev/null ||
        fatal "Ausgewähltes Profil konnte nicht gültig gespeichert werden."

    log "Profil $(jq -r '.profile.id' "${PROFILE_FILE}") wurde ausgewählt."
    log "Profilauswahl wurde unter ${PROFILE_FILE} gespeichert."
}

main() {
    require_root
    prepare_runtime
    validate_server_response
    show_profiles
    select_profile
}

main "$@"