#!/usr/bin/env bash
# BugWatch Server Monitoring Agent — Installer
# Usage: curl -sSL https://install.bugwatch.dev | bash -s -- --api-key <key>
# Version: 1.0

set -euo pipefail

# ============================================================================
# Defaults
# ============================================================================

BUGWATCH_API_KEY=""
BUGWATCH_ENDPOINT="https://api.bugwatch.dev"
BUGWATCH_INTERVAL=60
INSTALL_DIR="/opt/bugwatch"
CONFIG_DIR="/etc/bugwatch"
CONFIG_FILE="${CONFIG_DIR}/agent.conf"
AGENT_SCRIPT="${INSTALL_DIR}/agent.sh"

# ============================================================================
# Parse arguments
# ============================================================================

while [[ $# -gt 0 ]]; do
    case $1 in
        --api-key)
            BUGWATCH_API_KEY="$2"
            shift 2
            ;;
        --endpoint)
            BUGWATCH_ENDPOINT="$2"
            shift 2
            ;;
        --interval)
            BUGWATCH_INTERVAL="$2"
            shift 2
            ;;
        --help|-h)
            echo "BugWatch Server Agent Installer"
            echo ""
            echo "Usage:"
            echo "  curl -sSL https://install.bugwatch.dev | bash -s -- --api-key <key>"
            echo ""
            echo "Options:"
            echo "  --api-key    (required) Your BugWatch project API key"
            echo "  --endpoint   API endpoint (default: https://api.bugwatch.dev)"
            echo "  --interval   Collection interval in seconds (default: 60)"
            echo ""
            exit 0
            ;;
        *)
            echo "Unknown option: $1"
            exit 1
            ;;
    esac
done

# ============================================================================
# Validate
# ============================================================================

if [[ -z "$BUGWATCH_API_KEY" ]]; then
    echo "Error: --api-key is required"
    echo "Usage: curl -sSL https://install.bugwatch.dev | bash -s -- --api-key <key>"
    exit 1
fi

if ! command -v curl &>/dev/null; then
    echo "Error: curl is required but not installed"
    exit 1
fi

echo "================================================"
echo "  BugWatch Server Monitoring Agent Installer"
echo "================================================"
echo ""

# ============================================================================
# Create directories
# ============================================================================

echo "[1/5] Creating directories..."
mkdir -p "$INSTALL_DIR"
mkdir -p "$CONFIG_DIR"

# ============================================================================
# Write config
# ============================================================================

echo "[2/5] Writing configuration..."
cat > "$CONFIG_FILE" <<EOF
# BugWatch Agent Configuration
# Generated by install.sh on $(date -u +"%Y-%m-%dT%H:%M:%SZ")

BUGWATCH_API_KEY="${BUGWATCH_API_KEY}"
BUGWATCH_ENDPOINT="${BUGWATCH_ENDPOINT}"
BUGWATCH_INTERVAL=${BUGWATCH_INTERVAL}
BUGWATCH_COLLECT_DOCKER=auto
BUGWATCH_DISK_PATHS="/"
EOF

chmod 0600 "$CONFIG_FILE"
echo "  Config: $CONFIG_FILE"

# ============================================================================
# Install agent script
# ============================================================================

echo "[3/5] Installing agent script..."

# Try to download from the endpoint, fall back to embedded version
AGENT_URL="${BUGWATCH_ENDPOINT}/agent/agent.sh"
if curl -sSf "$AGENT_URL" -o "$AGENT_SCRIPT" 2>/dev/null; then
    echo "  Downloaded agent from $AGENT_URL"
else
    # Embedded fallback — write the agent inline
    cat > "$AGENT_SCRIPT" << 'AGENT_EOF'
#!/usr/bin/env bash
# BugWatch Server Monitoring Agent (embedded)
set -euo pipefail

CONFIG_FILE="/etc/bugwatch/agent.conf"
NET_PREV_FILE="/tmp/bugwatch_net_prev"

[[ -f "$CONFIG_FILE" ]] && source "$CONFIG_FILE"

BUGWATCH_API_KEY="${BUGWATCH_API_KEY:-}"
BUGWATCH_ENDPOINT="${BUGWATCH_ENDPOINT:-https://api.bugwatch.dev}"
BUGWATCH_COLLECT_DOCKER="${BUGWATCH_COLLECT_DOCKER:-auto}"
BUGWATCH_DISK_PATHS="${BUGWATCH_DISK_PATHS:-/}"

[[ -z "$BUGWATCH_API_KEY" ]] && { echo "Error: BUGWATCH_API_KEY not set" >&2; exit 1; }

json_escape() { printf '%s' "$1" | sed 's/\\/\\\\/g; s/"/\\"/g; s/\t/\\t/g; s/\n/\\n/g'; }

HOSTNAME_VAL=$(hostname 2>/dev/null || echo "unknown")
MACHINE_ID=$(head -c 8 /etc/machine-id 2>/dev/null || head -c 8 /var/lib/dbus/machine-id 2>/dev/null || echo "00000000")
SERVER_ID="${HOSTNAME_VAL}-${MACHINE_ID}"
OS_INFO=$(grep -oP '(?<=^PRETTY_NAME=").*(?="$)' /etc/os-release 2>/dev/null || echo "Linux")
KERNEL_VER=$(uname -r 2>/dev/null || echo "unknown")

read_cpu() { awk '/^cpu / {print $2+$3+$4, $5}' /proc/stat; }
CPU_B=$(read_cpu); sleep 1; CPU_A=$(read_cpu)
ACT_D=$(( $(echo "$CPU_A" | awk '{print $1}') - $(echo "$CPU_B" | awk '{print $1}') ))
IDL_D=$(( $(echo "$CPU_A" | awk '{print $2}') - $(echo "$CPU_B" | awk '{print $2}') ))
TOT_D=$((ACT_D + IDL_D))
[[ $TOT_D -gt 0 ]] && CPU_PCT=$(awk "BEGIN {printf \"%.1f\", ($ACT_D/$TOT_D)*100}") || CPU_PCT="0.0"

MEM_TOT=$(awk '/^MemTotal:/{print $2*1024}' /proc/meminfo)
MEM_AVL=$(awk '/^MemAvailable:/{print $2*1024}' /proc/meminfo)
MEM_USD=$((MEM_TOT - MEM_AVL))
[[ $MEM_TOT -gt 0 ]] && MEM_PCT=$(awk "BEGIN {printf \"%.1f\", ($MEM_USD/$MEM_TOT)*100}") || MEM_PCT="0.0"
SWP_TOT=$(awk '/^SwapTotal:/{print $2*1024}' /proc/meminfo)
SWP_FRE=$(awk '/^SwapFree:/{print $2*1024}' /proc/meminfo)
SWP_USD=$((SWP_TOT - SWP_FRE))

read -r L1 L5 L15 _ < /proc/loadavg

NET=$(awk 'NR>2 && $1!~/lo:/{rx+=$2;tx+=$10}END{print rx,tx}' /proc/net/dev)
NRX=$(echo "$NET"|awk '{print $1}'); NTX=$(echo "$NET"|awk '{print $2}')
NRXS=0; NTXS=0
if [[ -f "$NET_PREV_FILE" ]]; then
    read -r PRX PTX PTS < "$NET_PREV_FILE"
    EL=$(($(date +%s) - PTS))
    [[ $EL -gt 0 ]] && { NRXS=$(((NRX-PRX)/EL)); NTXS=$(((NTX-PTX)/EL)); }
    [[ $NRXS -lt 0 ]] && NRXS=0; [[ $NTXS -lt 0 ]] && NTXS=0
fi
echo "$NRX $NTX $(date +%s)" > "$NET_PREV_FILE"

UPT=$(awk '{printf "%d",$1}' /proc/uptime)

DISKS="["
FD=true
IFS=',' read -ra DPS <<< "$BUGWATCH_DISK_PATHS"
for DP in "${DPS[@]}"; do
    DP=$(echo "$DP"|xargs)
    if df -B1 "$DP" >/dev/null 2>&1; then
        DL=$(df -B1 "$DP"|tail -1)
        FS=$(echo "$DL"|awk '{print $1}')
        DT=$(echo "$DL"|awk '{print $2}')
        DU=$(echo "$DL"|awk '{print $3}')
        DA=$(echo "$DL"|awk '{print $4}')
        [[ $DT -gt 0 ]] && DP_PCT=$(awk "BEGIN {printf \"%.1f\",($DU/$DT)*100}") || DP_PCT="0.0"
        [[ "$FD" != "true" ]] && DISKS+=","
        DISKS+="{\"mount\":\"$(json_escape "$DP")\",\"filesystem\":\"$(json_escape "$FS")\",\"total_bytes\":$DT,\"used_bytes\":$DU,\"available_bytes\":$DA,\"usage_percent\":$DP_PCT}"
        FD=false
    fi
done
DISKS+="]"

PROCS="["
FP=true
while IFS= read -r line; do
    PU=$(echo "$line"|awk '{print $1}'); PP=$(echo "$line"|awk '{print $2}')
    PC=$(echo "$line"|awk '{print $3}'); PM=$(echo "$line"|awk '{print $4}')
    PN=$(echo "$line"|awk '{print $11}'|sed 's/.*\///')
    [[ "$FP" != "true" ]] && PROCS+=","
    PROCS+="{\"pid\":$PP,\"name\":\"$(json_escape "$PN")\",\"cpu_percent\":$PC,\"mem_percent\":$PM,\"user\":\"$(json_escape "$PU")\"}"
    FP=false
done < <(ps aux --sort=-%cpu 2>/dev/null|head -6|tail -5)
PROCS+="]"

DOCKER="null"
if [[ "$BUGWATCH_COLLECT_DOCKER" == "auto" || "$BUGWATCH_COLLECT_DOCKER" == "true" ]]; then
    if command -v docker &>/dev/null && docker info &>/dev/null 2>&1; then
        DOCKER="[]"
    fi
fi

PAYLOAD="{\"server_id\":\"$(json_escape "$SERVER_ID")\",\"hostname\":\"$(json_escape "$HOSTNAME_VAL")\",\"os\":\"$(json_escape "$OS_INFO")\",\"kernel\":\"$(json_escape "$KERNEL_VER")\",\"cpu\":{\"usage_percent\":$CPU_PCT},\"memory\":{\"total_bytes\":$MEM_TOT,\"used_bytes\":$MEM_USD,\"available_bytes\":$MEM_AVL,\"usage_percent\":$MEM_PCT},\"swap\":{\"total_bytes\":$SWP_TOT,\"used_bytes\":$SWP_USD},\"network\":{\"rx_bytes_per_sec\":$NRXS,\"tx_bytes_per_sec\":$NTXS},\"load\":{\"avg_1\":$L1,\"avg_5\":$L5,\"avg_15\":$L15},\"uptime_seconds\":$UPT,\"disks\":$DISKS,\"processes\":$PROCS,\"docker\":$DOCKER}"

curl -sS -o /dev/null -w "" -X POST \
    -H "Authorization: Bearer ${BUGWATCH_API_KEY}" \
    -H "Content-Type: application/json" \
    -H "X-Bugwatch-Agent: server-monitor/1.0" \
    -d "$PAYLOAD" \
    "${BUGWATCH_ENDPOINT}/api/v1/metrics" \
    --max-time 10 2>/dev/null || true
AGENT_EOF
    echo "  Used embedded agent script"
fi

chmod +x "$AGENT_SCRIPT"
echo "  Agent: $AGENT_SCRIPT"

# ============================================================================
# Setup systemd timer (or cron fallback)
# ============================================================================

echo "[4/5] Setting up scheduled execution..."

if command -v systemctl &>/dev/null && systemctl --version &>/dev/null 2>&1; then
    # systemd service
    cat > /etc/systemd/system/bugwatch-agent.service <<EOF
[Unit]
Description=BugWatch Server Monitoring Agent
After=network-online.target
Wants=network-online.target

[Service]
Type=oneshot
ExecStart=${AGENT_SCRIPT}
TimeoutStartSec=30
EOF

    # systemd timer
    cat > /etc/systemd/system/bugwatch-agent.timer <<EOF
[Unit]
Description=Run BugWatch agent every ${BUGWATCH_INTERVAL} seconds

[Timer]
OnBootSec=10
OnUnitActiveSec=${BUGWATCH_INTERVAL}s
AccuracySec=5s

[Install]
WantedBy=timers.target
EOF

    systemctl daemon-reload
    systemctl enable --now bugwatch-agent.timer
    echo "  Systemd timer active (every ${BUGWATCH_INTERVAL}s)"
else
    # Cron fallback
    CRON_ENTRY="* * * * * ${AGENT_SCRIPT} >/dev/null 2>&1"
    ( (crontab -l 2>/dev/null || true) | grep -v "bugwatch" || true; echo "$CRON_ENTRY") | crontab -
    echo "  Cron job installed (every minute)"
fi

# ============================================================================
# Verify connectivity
# ============================================================================

echo "[5/5] Verifying connectivity..."

if "$AGENT_SCRIPT" 2>/dev/null; then
    echo ""
    echo "================================================"
    echo "  BugWatch Agent installed successfully!"
    echo "================================================"
    echo ""
    echo "  Server ID:  $(hostname)-$(head -c 8 /etc/machine-id 2>/dev/null || echo '????????')"
    echo "  Config:     $CONFIG_FILE"
    echo "  Agent:      $AGENT_SCRIPT"
    echo "  Interval:   ${BUGWATCH_INTERVAL}s"
    echo ""
    echo "  Metrics should appear in your BugWatch dashboard"
    echo "  within a few minutes."
    echo ""
else
    echo ""
    echo "================================================"
    echo "  Agent installed but connectivity check failed"
    echo "================================================"
    echo ""
    echo "  The agent was installed but could not reach the"
    echo "  BugWatch API. Check your API key and endpoint."
    echo ""
    echo "  Config: $CONFIG_FILE"
    echo ""
fi