#!/bin/sh

SSH_PORT=${SSH_PORT:-20022}
SSH_USER=${SSH_USER:-"backup"}
SSH_PASSWORD=${SSH_PASSWORD:-"backup"}
HOME="/home/$SSH_USER"
SSH_DIR="$HOME/.ssh"
SSH_CONFIG_DIR="$HOME/.ssh/server"
SSH_HOST_KEYS_DIR="$SSH_CONFIG_DIR/keys"
SSH_CONFIG_FILE="$SSH_CONFIG_DIR/sshd_config"
SSH_PID_FILE="$SSH_CONFIG_DIR/sshd.pid"

if ! id -u "$SSH_USER" >/dev/null 2>&1; then
    echo "Creating user $SSH_USER..."
    adduser -D -s /bin/sh -h "/home/$SSH_USER" "$SSH_USER"
    # Ensure the user is properly initialized in shadow database
    passwd -u "$SSH_USER" 2>/dev/null || true
    # Add default ssh password if not set
    echo "$SSH_USER:$SSH_PASSWORD" | chpasswd
else
    echo "User $SSH_USER already exists."
fi

# Create necessary directories
mkdir -p "$SSH_HOST_KEYS_DIR"

# Generate host keys if they don't exist
for key_type in rsa ed25519; do
    if [ -f "$SSH_HOST_KEYS_DIR/ssh_host_${key_type}_key" ]; then
        echo "Host key for $key_type already exists, skipping generation."
        continue
    else
        key_file="$SSH_HOST_KEYS_DIR/ssh_host_${key_type}_key"
        echo "Generating $key_type host key..."
        ssh-keygen -t "$key_type" -f "$key_file" -N "" -q
    fi 
done

if [ ! -f $SSH_CONFIG_FILE ]; then
 
    cat >"$SSH_CONFIG_FILE" <<EOF
Port $SSH_PORT
ListenAddress 0.0.0.0
HostKey $SSH_HOST_KEYS_DIR/ssh_host_rsa_key
HostKey $SSH_HOST_KEYS_DIR/ssh_host_ed25519_key
PidFile $SSH_PID_FILE
UsePam yes
AuthorizedKeysFile $SSH_DIR/authorized_keys
PasswordAuthentication yes
PubkeyAuthentication yes
ChallengeResponseAuthentication no
PrintMotd no
AcceptEnv LANG LC_*
Subsystem sftp /usr/lib/openssh/sftp-server
EOF

fi

chown -R $SSH_USER:$SSH_USER "/home/$SSH_USER"
# Start SSH daemon
echo "Starting SSH server on port $SSH_PORT..."
exec su-exec $SSH_USER /usr/sbin/sshd.pam -D -f "$SSH_CONFIG_FILE" -e &

SSH_CONFIG_FILE=$SSH_CONFIG_FILE
LAST=$(md5sum "$SSH_CONFIG_FILE")
while true; do
    sleep 0.1
    if [ -f "$SSH_CONFIG_FILE" ]; then
        NEW=$(md5sum "$SSH_CONFIG_FILE")
        if [ "$NEW" != "$LAST" ]; then
            pkill -HUP sshd.pam
            LAST="$NEW"
        fi
    fi
done