#!/bin/bash
#
# LogWhisperer Agent - Script di Installazione
# Installa lo script di monitoraggio log e configura l'ambiente
#

set -euo pipefail

SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
INSTALL_DIR="/usr/local/bin"
CONFIG_DIR="/etc/logwhisperer"
DATA_DIR="/var/lib/logwhisperer"
LOG_DIR="/var/log/logwhisperer"

# Colori per output
RED='\033[0;31m'
GREEN='\033[0;32m'
YELLOW='\033[1;33m'
NC='\033[0m' # No Color

log_info() {
    echo -e "${GREEN}[INFO]${NC} $1"
}

log_warn() {
    echo -e "${YELLOW}[WARN]${NC} $1"
}

log_error() {
    echo -e "${RED}[ERROR]${NC} $1"
}

# Genera UUID v4
generate_uuid() {
    # Usa /proc/sys/kernel/random/uuid se disponibile (Linux)
    if [[ -r /proc/sys/kernel/random/uuid ]]; then
        cat /proc/sys/kernel/random/uuid
    else
        # Fallback con uuidgen o generazione manuale
        if command -v uuidgen &> /dev/null; then
            uuidgen
        else
            # Generazione manuale semplice
            local hex="0123456789abcdef"
            local uuid=""
            for i in {0..35}; do
                if [[ $i == 8 || $i == 13 || $i == 18 || $i == 23 ]]; then
                    uuid+="-"
                elif [[ $i == 14 ]]; then
                    uuid+="4"
                elif [[ $i == 19 ]]; then
                    uuid+="${hex:$((RANDOM % 4 + 8)):1}"
                else
                    uuid+="${hex:$((RANDOM % 16)):1}"
                fi
            done
            echo "$uuid"
        fi
    fi
}

# Verifica prerequisiti
check_prerequisites() {
    log_info "Verifica prerequisiti..."
    
    # Verifica bash
    if [[ "${BASH_VERSION:-}" < "4.0" ]]; then
        log_error "Richiesto Bash 4.0 o superiore"
        exit 1
    fi
    
    # Verifica curl
    if ! command -v curl &> /dev/null; then
        log_error "curl non trovato. Installa curl: apt-get install curl / yum install curl"
        exit 1
    fi
    
    # Verifica permessi root per installazione system-wide
    if [[ $EUID -ne 0 ]]; then
        log_warn "Esecuzione senza root. Installazione in modalità utente..."
        INSTALL_DIR="$HOME/.local/bin"
        CONFIG_DIR="$HOME/.config/logwhisperer"
        DATA_DIR="$HOME/.local/share/logwhisperer"
        LOG_DIR="$HOME/.local/log/logwhisperer"
    fi
    
    log_info "Prerequisiti OK"
}

# Crea directory necessarie
create_directories() {
    log_info "Creazione directory..."
    
    mkdir -p "$CONFIG_DIR"
    mkdir -p "$DATA_DIR"
    mkdir -p "$LOG_DIR"
    mkdir -p "$INSTALL_DIR"
    
    log_info "Directory create"
}

# Configura il client
configure_client() {
    log_info "Configurazione LogWhisperer..."
    
    local config_file="$CONFIG_DIR/config.env"
    local client_id
    local webhook_url
    local log_sources
    
    # Genera CLIENT_ID
    client_id=$(generate_uuid)
    log_info "Client ID generato: $client_id"
    
    # Chiedi WEBHOOK_URL
    echo ""
    echo "=========================================="
    echo "Configurazione Webhook"
    echo "=========================================="
    read -p "Inserisci l'URL del webhook n8n: " webhook_url
    
    if [[ -z "$webhook_url" ]]; then
        log_warn "Nessun webhook URL fornito. Lo script funzionerà in modalità offline."
        webhook_url=""
    elif [[ ! "$webhook_url" =~ ^https:// ]]; then
        log_warn "L'URL non usa HTTPS. Si consiglia di usare HTTPS per la sicurezza."
    fi
    
    # Configura LOG_SOURCES
    echo ""
    echo "=========================================="
    echo "Configurazione Sorgenti Log"
    echo "=========================================="
    
    # Rileva sistema e propone defaults
    local default_sources="/var/log/syslog"
    if [[ -f /etc/redhat-release ]]; then
        default_sources="/var/log/messages"
    fi
    
    if [[ -f /var/log/nginx/error.log ]]; then
        default_sources="$default_sources,/var/log/nginx/error.log"
    fi
    
    if [[ -d /var/log/postgresql ]]; then
        default_sources="$default_sources,/var/log/postgresql/*.log"
    fi
    
    read -p "Sorgenti log da monitorare [$default_sources]: " log_sources
    log_sources="${log_sources:-$default_sources}"
    
    # Chiedi POLL_INTERVAL
    echo ""
    read -p "Intervallo di polling in secondi [5]: " poll_interval
    poll_interval="${poll_interval:-5}"
    
    # Scrivi configurazione
    cat > "$config_file" <<EOF
# LogWhisperer Configuration
# Generato automaticamente il $(date)

WEBHOOK_URL="$webhook_url"
CLIENT_ID="$client_id"
LOG_SOURCES="$log_sources"
POLL_INTERVAL=$poll_interval
MAX_LINE_LENGTH=2000
EOF
    
    chmod 600 "$config_file"
    log_info "Configurazione salvata in: $config_file"
    
    # Mostra riepilogo
    echo ""
    echo "=========================================="
    echo "Riepilogo Configurazione"
    echo "=========================================="
    echo "Client ID: $client_id"
    echo "Webhook URL: ${webhook_url:-<non configurato>}"
    echo "Log Sources: $log_sources"
    echo "Poll Interval: ${poll_interval}s"
    echo "Config File: $config_file"
    echo "=========================================="
}

# Installa lo script
install_script() {
    log_info "Installazione script..."
    
    local source_script="$SCRIPT_DIR/logwhisperer.sh"
    local target_script="$INSTALL_DIR/logwhisperer"
    
    if [[ ! -f "$source_script" ]]; then
        log_error "Script sorgente non trovato: $source_script"
        exit 1
    fi
    
    cp "$source_script" "$target_script"
    chmod +x "$target_script"
    
    log_info "Script installato in: $target_script"
}

# Crea systemd service (se root)
create_systemd_service() {
    if [[ $EUID -ne 0 ]]; then
        log_info "Installazione utente: salto creazione servizio systemd"
        return 0
    fi
    
    log_info "Creazione servizio systemd..."
    
    local service_file="/etc/systemd/system/logwhisperer.service"
    
    cat > "$service_file" <<EOF
[Unit]
Description=LogWhisperer Agent - Log Monitoring Service
After=network.target

[Service]
Type=simple
ExecStart=$INSTALL_DIR/logwhisperer --config $CONFIG_DIR/config.env
Restart=always
RestartSec=10
User=root
Group=adm
StandardOutput=append:$LOG_DIR/agent.log
StandardError=append:$LOG_DIR/agent.log

[Install]
WantedBy=multi-user.target
EOF
    
    systemctl daemon-reload
    log_info "Servizio systemd creato"
    log_info "Per avviare: systemctl start logwhisperer"
    log_info "Per abilitare all'avvio: systemctl enable logwhisperer"
}

# Testa l'installazione
test_installation() {
    log_info "Test installazione..."
    
    if ! command -v logwhisperer &> /dev/null; then
        # Aggiungi a PATH se necessario
        if [[ $EUID -ne 0 ]]; then
            log_warn "Aggiungi $INSTALL_DIR al tuo PATH:"
            echo "  export PATH=\"\$PATH:$INSTALL_DIR\""
            echo "  oppure riavvia la shell"
        fi
    fi
    
    # Testa la configurazione
    local config_file="$CONFIG_DIR/config.env"
    if [[ -f "$config_file" ]]; then
        # shellcheck source=/dev/null
        source "$config_file"
        
        if [[ -n "${WEBHOOK_URL:-}" ]]; then
            log_info "Test di connettività al webhook..."
            if curl -s -o /dev/null -w "%{http_code}" "$WEBHOOK_URL" | grep -q "200\\|404"; then
                log_info "Webhook raggiungibile"
            else
                log_warn "Webhook non raggiungibile. Verifica l'URL."
            fi
        fi
    fi
    
    log_info "Test completato"
}

# Mostra istruzioni finali
show_instructions() {
    echo ""
    echo "=========================================="
    echo "Installazione Completata!"
    echo "=========================================="
    echo ""
    echo "Comandi disponibili:"
    echo "  logwhisperer --help              Mostra help"
    echo "  logwhisperer --validate          Verifica configurazione"
    echo "  logwhisperer --dry-run --test-line 'FATAL error'  Test pattern"
    echo ""
    
    if [[ $EUID -eq 0 ]]; then
        echo "Gestione servizio:"
        echo "  systemctl start logwhisperer     Avvia servizio"
        echo "  systemctl stop logwhisperer      Ferma servizio"
        echo "  systemctl status logwhisperer    Stato servizio"
        echo "  journalctl -u logwhisperer -f    Log servizio"
        echo ""
    fi
    
    echo "File importanti:"
    echo "  Config: $CONFIG_DIR/config.env"
    echo "  Logs:   $LOG_DIR/"
    echo "  Data:   $DATA_DIR/"
    echo ""
    echo "Prossimi passi:"
    echo "  1. Verifica la configurazione: logwhisperer --validate"
    echo "  2. Testa il pattern matching: logwhisperer --dry-run --test-line 'ERROR test'"
    echo "  3. Avvia il monitoraggio"
    
    if [[ $EUID -eq 0 ]]; then
        echo "     systemctl start logwhisperer"
    else
        echo "     logwhisperer --config $CONFIG_DIR/config.env"
    fi
    echo ""
    echo "=========================================="
}

# Main
main() {
    echo ""
    echo "╔══════════════════════════════════════════╗"
    echo "║      LogWhisperer Agent Installer        ║"
    echo "║          Versione 1.0.0                  ║"
    echo "╚══════════════════════════════════════════╝"
    echo ""
    
    check_prerequisites
    create_directories
    configure_client
    install_script
    create_systemd_service
    test_installation
    show_instructions
}

# Se eseguito direttamente
if [[ "${BASH_SOURCE[0]}" == "${0}" ]]; then
    main "$@"
fi