#!/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.

MONITORING_LIB_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"  
MONITORING_BASE_DIR="$(cd "${MONITORING_LIB_DIR}/.." && pwd)"  
MONITORING_CONF_DIR="${MONITORING_BASE_DIR}/conf"

# Chargement config globale
if [ -f "${MONITORING_CONF_DIR}/monitoring.conf" ]; then
    # shellcheck source=/dev/null
    . "${MONITORING_CONF_DIR}/monitoring.conf"
fi

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

STATUS_OK=0
STATUS_WARNING=1
STATUS_ERROR=2
STATUS_INTERNAL=3

CURRENT_STATUS=$STATUS_OK

LOG_LEVEL=${LOG_LEVEL:-INFO}

json_escape() {
    local s="${1:-}"
    s="${s//\\/\\\\}"
    s="${s//\"/\\\"}"
    s="${s//$'\n'/\\n}"
    s="${s//$'\r'/\\r}"
    s="${s//$'\t'/\\t}"
    printf '%s' "$s"
}

log_event() {
    local level="$1"
    local event="$2"
    local message="$3"
    shift 3

    local ts extra key value kv host
    ts="$(date --iso-8601=seconds)"
    
    # Détection dynamique du hostname si HOSTNAME_FQDN n'est pas défini
    # On utilise 'hostname -f' pour le nom complet ou 'hostname' en secours
    host="${HOSTNAME_FQDN:-$(hostname -f 2>/dev/null || hostname)}"
    
    extra=""

    for kv in "$@"; do
        key="${kv%%=*}"
        value="${kv#*=}"
        extra="${extra},\"$(json_escape "$key")\":\"$(json_escape "$value")\""
    done

    # Utilisation de la variable 'host' détectée ci-dessus
    printf '{"ts":"%s","host":"%s","app":"%s","level":"%s","event":"%s","message":"%s"%s}\n' \
        "$(json_escape "$ts")" \
        "$(json_escape "$host")" \
        "$(json_escape "$SCRIPT_NAME")" \
        "$(json_escape "$level")" \
        "$(json_escape "$event")" \
        "$(json_escape "$message")" \
        "$extra" >> "${LOG_FILE:-/var/log/monitoring/events.jsonl}"
}

set_status() {
    local new_status="$1"
    if [ "$new_status" -gt "$CURRENT_STATUS" ]; then
        CURRENT_STATUS="$new_status"
    fi
}

log_debug()    { log_event "DEBUG"    "$@"; }
log_info()     { log_event "INFO"     "$@"; }
log_notice()   { log_event "NOTICE"   "$@"; }
log_warning()  { log_event "WARNING"  "$@"; set_status "$STATUS_WARNING"; }
log_error()    { log_event "ERROR"    "$@"; set_status "$STATUS_ERROR"; }
log_critical() { log_event "CRITICAL" "$@"; set_status "$STATUS_ERROR"; }

fail_internal() {
    log_event "ERROR" "internal_error" "$1"
    exit "$STATUS_INTERNAL"
}

exit_with_status() {
    exit "$CURRENT_STATUS"
}

require_cmd() {
    local cmd
    for cmd in "$@"; do
        command -v "$cmd" >/dev/null 2>&1 || fail_internal "Commande requise absente: $cmd"
    done
}

load_conf_if_exists() {
    local conf="$1"
    [ -f "$conf" ] && . "$conf"
}

lock_or_exit() {
    local lock_name="${1:-$SCRIPT_NAME}"
    local lock_file="${MONITORING_LOCK_DIR:-/var/lock/monitoring}/${lock_name}.lock"

    exec 9>"$lock_file" || fail_internal "Impossible d'ouvrir le lock $lock_file"
    flock -n 9 || {
        log_notice "already_running" "Une autre instance est déjà en cours" "lock=$lock_file"
        exit 0
    }
}

threshold_level() {
    local value="$1"
    local warning="$2"
    local critical="$3"

    if [ "$value" -ge "$critical" ]; then
        printf 'CRITICAL'
    elif [ "$value" -ge "$warning" ]; then
        printf 'WARNING'
    else
        printf 'INFO'
    fi
}

safe_mv() {
    local src="$1"
    local dst="$2"
    mv -f "$src" "$dst" || fail_internal "Échec du déplacement de $src vers $dst"
}

ensure_parent_dir() {  
	local file="$1"  
	mkdir -p "$(dirname "$file")" || fail_internal "Impossible de créer le répertoire parent de $file"  
}