#!/bin/bash
# Copyright (C) 2026 Cédric Abonnel
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU Affero General Public License for more details.

set -u

SCRIPT_NAME="$(basename "$0")"
SCRIPT_PATH="$(readlink -f "$0" 2>/dev/null || realpath "$0" 2>/dev/null || echo "$0")"

# shellcheck source=/opt/monitoring/lib/monitoring-lib.sh
. /opt/monitoring/lib/monitoring-lib.sh || exit 3

load_conf_if_exists "/opt/monitoring/conf/autoupdate.conf"
load_conf_if_exists "/opt/monitoring/conf/autoupdate.local.conf"

# Définir les variables par défaut si elles ne sont pas dans les fichiers .conf
UPDATE_TMP_DIR="${UPDATE_TMP_DIR:-/tmp/monitoring-update}"
UPDATE_TIMEOUT_CONNECT="${UPDATE_TIMEOUT_CONNECT:-3}"
UPDATE_TIMEOUT_TOTAL="${UPDATE_TIMEOUT_TOTAL:-15}"
UPDATE_MANIFEST_URL="${UPDATE_MANIFEST_URL:-}"
UPDATE_BASE_URL="${UPDATE_BASE_URL:-}"

lock_or_exit "monitoring-update"
require_cmd curl sha256sum awk mktemp chmod dirname mv rm grep sed sort comm cut tr find

[ "${UPDATE_ENABLED:-true}" = "true" ] || {
    log_notice "update_disabled" "Mise à jour désactivée par configuration"
    exit 0
}

mkdir -p "${UPDATE_TMP_DIR:-/tmp/monitoring-update}" || fail_internal "Impossible de créer le répertoire temporaire"

TMP_MANIFEST="$(mktemp "${UPDATE_TMP_DIR}/manifest.XXXXXX")" || fail_internal "mktemp a échoué"
TMP_LOCAL_LIST="$(mktemp "${UPDATE_TMP_DIR}/local.XXXXXX")" || fail_internal "mktemp a échoué"
TMP_REMOTE_LIST="$(mktemp "${UPDATE_TMP_DIR}/remote.XXXXXX")" || fail_internal "mktemp a échoué"

cleanup() {
    rm -f "$TMP_MANIFEST" "$TMP_LOCAL_LIST" "$TMP_REMOTE_LIST"
}
trap cleanup EXIT

fetch_manifest() {
    if ! curl -fsS \
        --connect-timeout "${UPDATE_TIMEOUT_CONNECT:-3}" \
        --max-time "${UPDATE_TIMEOUT_TOTAL:-15}" \
        "${UPDATE_MANIFEST_URL}" \
        -o "$TMP_MANIFEST"; then
        log_error "manifest_download_failed" \
            "Impossible de télécharger le manifeste" \
            "url=${UPDATE_MANIFEST_URL}"
        return 1
    fi

    if ! awk '
        NF == 3 &&
        $1 ~ /^[0-9a-fA-F]{64}$/ &&
        $2 ~ /^(644|755)$/ &&
        $3 ~ /^(bin|lib|conf)\/[A-Za-z0-9._\/-]+$/ &&
        $3 !~ /\.\./
    ' "$TMP_MANIFEST" >/dev/null; then
        log_error "manifest_invalid" \
            "Le manifeste distant est invalide" \
            "url=${UPDATE_MANIFEST_URL}"
        return 1
    fi

    log_info "manifest_downloaded" "Manifeste téléchargé" "url=${UPDATE_MANIFEST_URL}"
    return 0
}

list_remote_files() {
    awk '{print $3}' "$TMP_MANIFEST" | sort -u > "$TMP_REMOTE_LIST"
}

list_local_files() {
    find "${MONITORING_BASE_DIR}/bin" "${MONITORING_BASE_DIR}/lib" "${MONITORING_BASE_DIR}/conf" \
        -type f 2>/dev/null \
        | sed "s#^${MONITORING_BASE_DIR}/##" \
        | sort -u > "$TMP_LOCAL_LIST"
}

apply_mode() {
    local mode="$1"
    local file="$2"

    case "$mode" in
        755) chmod 755 "$file" ;;
        644) chmod 644 "$file" ;;
        *) fail_internal "Mode non supporté: $mode" ;;
    esac
}

update_one_file() {
    local expected_hash="$1"
    local mode="$2"
    local rel_path="$3"

    local local_file="${MONITORING_BASE_DIR}/${rel_path}"
    local remote_file="${UPDATE_BASE_URL}/${rel_path}"
    local tmp_file local_hash downloaded_hash

    tmp_file="$(mktemp "${UPDATE_TMP_DIR}/$(basename "$rel_path").XXXXXX")" || fail_internal "mktemp a échoué"

    if [ -f "$local_file" ]; then
        local_hash="$(sha256sum "$local_file" | awk '{print $1}')"
    else
        local_hash=""
    fi

    if [ "$local_hash" = "$expected_hash" ]; then
        log_debug "update_not_needed" "Fichier déjà à jour" "file=$rel_path"
        rm -f "$tmp_file"
        return 0
    fi

    if ! curl -fsS \
        --connect-timeout "${UPDATE_TIMEOUT_CONNECT:-3}" \
        --max-time "${UPDATE_TIMEOUT_TOTAL:-15}" \
        "$remote_file" \
        -o "$tmp_file"; then
        log_error "update_download_failed" \
            "Téléchargement impossible" \
            "file=$rel_path" "url=$remote_file"
        rm -f "$tmp_file"
        return 1
    fi

    downloaded_hash="$(sha256sum "$tmp_file" | awk '{print $1}')"
    if [ "$downloaded_hash" != "$expected_hash" ]; then
        log_error "update_hash_mismatch" \
            "Hash téléchargé invalide" \
            "file=$rel_path" "expected=$expected_hash" "got=$downloaded_hash"
        rm -f "$tmp_file"
        return 1
    fi

    ensure_parent_dir "$local_file"
    apply_mode "$mode" "$tmp_file"
    safe_mv "$tmp_file" "$local_file"

    if [ -z "$local_hash" ]; then
        log_notice "file_created" \
            "Fichier créé depuis le manifeste" \
            "file=$rel_path" "mode=$mode" "hash=$expected_hash"
    else
        log_notice "update_applied" \
            "Mise à jour appliquée" \
            "file=$rel_path" "mode=$mode" "old_hash=$local_hash" "new_hash=$expected_hash"
    fi

    return 0
}

delete_extra_local_files() {
    [ "${UPDATE_ALLOW_DELETE:-false}" = "true" ] || return 0

    comm -23 "$TMP_LOCAL_LIST" "$TMP_REMOTE_LIST" | while IFS= read -r rel_path; do
        [ -n "$rel_path" ] || continue

        case "$rel_path" in
            conf/alert-engine.local.conf|conf/autoupdate.local.conf|conf/monitoring.local.conf)
                log_notice "delete_skipped" \
                    "Suppression ignorée pour fichier local protégé" \
                    "file=$rel_path"
                continue
                ;;
        esac

        rm -f "${MONITORING_BASE_DIR}/${rel_path}" \
            && log_notice "file_deleted" \
                "Fichier supprimé car absent du manifeste" \
                "file=$rel_path" \
            || log_error "delete_failed" \
                "Impossible de supprimer le fichier local absent du manifeste" \
                "file=$rel_path"
    done
}

main() {
    local total=0 updated_or_checked=0 failed=0
    local hash mode path

    fetch_manifest || exit 2
    list_remote_files
    list_local_files

    while read -r hash mode path; do
        [ -n "${hash:-}" ] || continue
        total=$((total + 1))

        if update_one_file "$hash" "$mode" "$path"; then
            updated_or_checked=$((updated_or_checked + 1))
        else
            failed=$((failed + 1))
        fi
    done < "$TMP_MANIFEST"

    delete_extra_local_files

    if [ "$failed" -gt 0 ]; then
        log_warning "update_finished_with_errors" \
            "Mise à jour terminée avec erreurs" \
            "total=$total" "updated_or_checked=$updated_or_checked" "failed=$failed"
    else
        log_info "update_finished" \
            "Mise à jour terminée" \
            "total=$total" "updated_or_checked=$updated_or_checked" "failed=0"
    fi
}

main
exit_with_status