#!/usr/bin/env bash
# Install we_monitor as a systemd user service.
#
# What this script does:
#   1. Creates ~/.config/we_monitor/ and a credentials template if missing
#   2. Writes a systemd user service unit
#   3. Enables the service (does not start it — edit credentials first)
#
# Usage:
#   chmod +x install.sh
#   ./install.sh
#   # then edit ~/.config/we_monitor/credentials.json
#   systemctl --user start we_monitor

set -euo pipefail

SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
SERVICE_NAME="we_monitor"
CREDS_DIR="$HOME/.config/we_monitor"
CREDS_FILE="$CREDS_DIR/credentials.json"
SYSTEMD_DIR="$HOME/.config/systemd/user"
SERVICE_FILE="$SYSTEMD_DIR/$SERVICE_NAME.service"
LOG_DIR="$SCRIPT_DIR/logs"

VENV="$SCRIPT_DIR/.venv"
PYTHON="$VENV/bin/python"

echo "==> we_monitor installer"
echo "    Project : $SCRIPT_DIR"
echo "    User    : $USER"
echo ""

# ── 1. virtual environment ────────────────────────────────────────────────────
if [[ ! -x "$PYTHON" ]]; then
    echo "==> Creating virtual environment : $VENV"
    python3 -m venv "$VENV"
else
    echo "==> Virtual environment exists   : $VENV"
fi

echo "==> Installing / updating dependencies"
"$VENV/bin/pip" install --quiet --upgrade pip
"$VENV/bin/pip" install --quiet -r "$SCRIPT_DIR/requirements.txt"
echo "    Python  : $PYTHON"
echo ""

# ── 2. credentials template ───────────────────────────────────────────────────
mkdir -p "$CREDS_DIR"
chmod 700 "$CREDS_DIR"

if [[ ! -f "$CREDS_FILE" ]]; then
    cat > "$CREDS_FILE" <<'EOF'
{
  "username": "me@example.com",
  "password": "secret",
  "vin":      "",
  "domains":  ["charging", "measurements", "readiness"]
}
EOF
    chmod 600 "$CREDS_FILE"
    echo "==> Created credentials template : $CREDS_FILE"
    echo "    *** Edit this file before starting the service! ***"
else
    echo "==> Credentials file exists      : $CREDS_FILE"
fi

# ── 3. log directory ──────────────────────────────────────────────────────────
mkdir -p "$LOG_DIR"
echo "==> Log directory                : $LOG_DIR"

# ── 4. systemd user service ───────────────────────────────────────────────────
mkdir -p "$SYSTEMD_DIR"

cat > "$SERVICE_FILE" <<EOF
[Unit]
Description=WeConnect vehicle data collector
After=network-online.target
Wants=network-online.target

[Service]
Type=simple
WorkingDirectory=$SCRIPT_DIR
ExecStart=$PYTHON $SCRIPT_DIR/collect.py -c $CREDS_FILE
Restart=on-failure
RestartSec=60
StandardOutput=journal
StandardError=journal
SyslogIdentifier=$SERVICE_NAME

[Install]
WantedBy=default.target
EOF

echo "==> Installed service unit       : $SERVICE_FILE"

# ── 5. enable linger (service survives logout / starts at boot) ───────────────
if loginctl enable-linger "$USER" 2>/dev/null; then
    echo "==> Linger enabled for $USER (service starts at boot)"
else
    echo "    Note: could not enable linger — service runs only while logged in"
    echo "    Run as root to fix: loginctl enable-linger $USER"
fi

# ── 6. reload and enable (but do NOT start yet) ───────────────────────────────
systemctl --user daemon-reload
systemctl --user enable "$SERVICE_NAME"

echo ""
echo "━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━"
echo " Installation complete."
echo ""
echo " Next steps:"
echo "   1. Edit credentials:"
echo "        \$EDITOR $CREDS_FILE"
echo ""
echo "   2. Start the service:"
echo "        systemctl --user start $SERVICE_NAME"
echo ""
echo "   3. Check status:"
echo "        systemctl --user status $SERVICE_NAME"
echo ""
echo "   4. Follow logs:"
echo "        journalctl --user -u $SERVICE_NAME -f"
echo "━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━"