#!/usr/bin/env bash
# GitKS bare-metal installation script
#
# Installs the gitks binary, systemd service, environment config,
# logrotate config, and creates the service user and data directory.
#
# Usage:
#   sudo ./install.sh                     # install from local build
#   sudo ./install.sh /path/to/gitks      # install from prebuilt binary
#   sudo GITKS_USER=custom ./install.sh   # use a different service user

set -euo pipefail

GITKS_USER="${GITKS_USER:-gitks}"
GITKS_GROUP="${GITKS_GROUP:-gitks}"
BINARY_SRC="${1:-target/release/gitks}"
INSTALL_PREFIX="${INSTALL_PREFIX:-/usr/local}"
DATA_DIR="${DATA_DIR:-/data/repos}"

RED='\033[0;31m'
GREEN='\033[0;32m'
YELLOW='\033[1;33m'
NC='\033[0m'

log()  { echo -e "${GREEN}[INFO]${NC}  $*"; }
warn() { echo -e "${YELLOW}[WARN]${NC}  $*"; }
err()  { echo -e "${RED}[ERROR]${NC} $*"; exit 1; }

# ── Preflight checks ──────────────────────────────────────────────
[[ $EUID -eq 0 ]] || err "This script must be run as root (use sudo)"

SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
PROJECT_DIR="$(dirname "$SCRIPT_DIR")"

command -v git >/dev/null 2>&1 || {
    warn "git not found in PATH. Installing git..."
    if command -v apt-get >/dev/null 2>&1; then
        apt-get update -qq && apt-get install -y -qq git
    elif command -v yum >/dev/null 2>&1; then
        yum install -y git
    elif command -v dnf >/dev/null 2>&1; then
        dnf install -y git
    else
        err "Cannot install git automatically. Please install git first."
    fi
}

# ── Create service user ───────────────────────────────────────────
if id "$GITKS_USER" &>/dev/null; then
    log "User '$GITKS_USER' already exists"
else
    log "Creating system user '$GITKS_USER'"
    useradd --system --user-group --home-dir /var/lib/gitks \
        --shell /usr/sbin/nologin --comment "GitKS service" "$GITKS_USER"
fi

# ── Install binary ────────────────────────────────────────────────
BINARY_DST="${INSTALL_PREFIX}/bin/gitks"
if [[ -f "$BINARY_SRC" ]]; then
    log "Installing gitks binary: $BINARY_SRC → $BINARY_DST"
    install -o root -g root -m 0755 "$BINARY_SRC" "$BINARY_DST"
elif [[ -f "$PROJECT_DIR/$BINARY_SRC" ]]; then
    log "Installing gitks binary: $PROJECT_DIR/$BINARY_SRC → $BINARY_DST"
    install -o root -g root -m 0755 "$PROJECT_DIR/$BINARY_SRC" "$BINARY_DST"
else
    warn "Binary not found at '$BINARY_SRC'. Skipping binary install."
    warn "Build first: cargo build --release"
    warn "Or specify path: sudo ./install.sh /path/to/gitks"
fi

# ── Create directories ────────────────────────────────────────────
log "Creating directories..."
install -d -o "$GITKS_USER" -g "$GITKS_GROUP" -m 0750 /var/lib/gitks
install -d -o "$GITKS_USER" -g "$GITKS_GROUP" -m 0750 /var/log/gitks
install -d -o root -g root -m 0755 /etc/gitks
[[ -d "$DATA_DIR" ]] || {
    log "Creating repo data directory: $DATA_DIR"
    mkdir -p "$DATA_DIR"
    chown "$GITKS_USER:$GITKS_GROUP" "$DATA_DIR"
}

# ── Install config ────────────────────────────────────────────────
CONF_SRC="${PROJECT_DIR}/etc/gitks.env"

if [[ -f /etc/gitks/gitks.env ]]; then
    warn "/etc/gitks/gitks.env already exists — skipping (preserving existing config)"
else
    log "Installing environment config..."
    install -o root -g "$GITKS_GROUP" -m 0640 "$CONF_SRC" /etc/gitks/gitks.env
    log "Edit /etc/gitks/gitks.env to configure your deployment"
fi

# ── Install systemd service ───────────────────────────────────────
log "Installing systemd service..."
install -o root -g root -m 0644 \
    "${PROJECT_DIR}/etc/systemd/gitks.service" \
    /etc/systemd/system/gitks.service

# ── Install logrotate config ──────────────────────────────────────
LOG_ROTATE_SRC="${PROJECT_DIR}/etc/logrotate.d/gitks"
if [[ -d /etc/logrotate.d ]]; then
    if [[ -f /etc/logrotate.d/gitks ]]; then
        warn "/etc/logrotate.d/gitks already exists — skipping"
    else
        log "Installing logrotate config..."
        install -o root -g root -m 0644 "$LOG_ROTATE_SRC" /etc/logrotate.d/gitks
    fi
fi

# ── Reload systemd & enable ───────────────────────────────────────
log "Reloading systemd..."
systemctl daemon-reload

log "Enabling gitks to start on boot..."
systemctl enable gitks.service

# ── Done ──────────────────────────────────────────────────────────
echo ""
log "Installation complete!"
echo ""
echo "  Next steps:"
echo "    1. Edit config:   vim /etc/gitks/gitks.env"
echo "    2. Start service: systemctl start gitks"
echo "    3. Check status:  systemctl status gitks"
echo "    4. View logs:     journalctl -fu gitks"
echo ""
echo "  Cluster setup (multi-node):"
echo "    - Set STORAGE_NAME uniquely per node"
echo "    - Set GITKS_CLUSTER_HOSTNAME to each node's hostname"
echo "    - Set GITKS_ADVERTISE_ADDR to each node's reachable IP:port"
echo "    - Point GITKS_ETCD_ENDPOINTS to your etcd cluster"
echo ""