#!/bin/bash

set -e

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

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

log_success() {
    echo -e "${GREEN}[SUCCESS]${NC} $1"
}

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

# -----------------------------------------------------------------------------
# Input Framework
# -----------------------------------------------------------------------------

# Ensure we have a tty for input
if [ ! -e /dev/tty ]; then
    echo "Error: Script must be run in an interactive terminal (cannot find /dev/tty)." >&2
    exit 1
fi

# Function to prompt for user input
# Usage: get_input "VARIABLE_NAME" "Prompt Text" "Default Value" "is_secret(true/false)"
get_input() {
    local var_name="$1"
    local prompt_text="$2"
    local default_value="$3"
    local is_secret="$4"

    local input_val=""
    local prompt_full="${GREEN}${prompt_text}${NC}"

    if [ -n "$default_value" ]; then
        prompt_full+=" [$default_value]"
    fi
    prompt_full+=": "

    while true; do
        # Print prompt to stderr so it shows up even if stdout is redirected
        if [ "$is_secret" == "true" ]; then
            echo -ne "$prompt_full" >&2
            read -s input_val < /dev/tty
            echo "" >&2 # Newline after secret input
        else
            echo -ne "$prompt_full" >&2
            read input_val < /dev/tty
        fi

        # Use default if input is empty
        if [ -z "$input_val" ] && [ -n "$default_value" ]; then
            input_val="$default_value"
        fi

        # Validation: Require input if no default exists
        if [ -z "$input_val" ]; then
            echo -e "${RED}Error: This value is required.${NC}" >&2
        else
            break
        fi
    done

    # Set the variable dynamically in the parent scope
    printf -v "$var_name" "%s" "$input_val"
    export "$var_name=$input_val"
}

# Function to confirm collected inputs
# Usage: confirm_inputs "VAR1" "VAR2" "VAR3" ...
confirm_inputs() {
    echo "" >&2
    echo -e "${GREEN}=== Configuration Summary ===${NC}" >&2
    
    for var in "$@"; do
        local val="${!var}"
        # Mask secrets in summary if needed, or just show length
        # For now, just printing value. 
        # To improve: pass a list of secret vars to mask them.
        echo -e "${YELLOW}$var:${NC} $val" >&2
    done
    echo "" >&2
    
    get_input "CONFIRM" "Is this correct? (y/n)" "y" "false"
    if [[ "${CONFIRM,,}" != "y" ]]; then
        echo -e "${RED}Aborted by user.${NC}" >&2
        exit 1
    fi
}

install_unit() {
    local template_url=$1
    local filename=$(basename "$template_url")
    local dest_path=/etc/systemd/system/"$filename"

    if [ -e "$dest_path" ]; then
        get_input "CONFIRM_OVERWRITE" "Overwrite $dest_path? (y/n)" "y" "false"
        if [[ "${CONFIRM_OVERWRITE,,}" != "y" ]]; then
            echo "Skipping overwrite of ${dest_path}."
            return
        fi
    fi

    log_info "Installing $filename..."
    curl -sL $template_url | envsubst > "$dest_path"
    log_success "$filename installed to $dest_path"
}

# -----------------------------------------------------------------------------
# Script Logic
# -----------------------------------------------------------------------------

echo "Starting Interactive Setup..."
echo "-----------------------------"

# Verify required external binaries
if ! command -v step >/dev/null 2>&1; then
    # Prompt the user to install the step CLI
    get_input "INSTALL_STEP" "The 'step' CLI was not found. Install now? (y/n)" "y" "false"

    if [[ "${INSTALL_STEP,,}" == "y" ]]; then
        apt-get update && apt-get install -y --no-install-recommends curl vim gpg ca-certificates
        curl -fsSL https://packages.smallstep.com/keys/apt/repo-signing-key.gpg -o /etc/apt/trusted.gpg.d/smallstep.asc && \
            echo 'deb [signed-by=/etc/apt/trusted.gpg.d/smallstep.asc] https://packages.smallstep.com/stable/debian debs main' \
            | tee /etc/apt/sources.list.d/smallstep.list
        apt-get update && apt-get -y install step-cli step-ca
    else
        log_error "Cannot continue without 'step'. Aborting." >&2
        exit 1
    fi
else
    log_success "Step CA installed\n"
fi

get_input "CERT_DIR" "Enter directory for certificates" "/var/lib/tls" "false"
get_input "CERT_FILENAME" "Name for cert file" "cert.pem" "false"
get_input "KEY_FILENAME" "Name for private key" "key.pem" "false"

if [ ! -e "$CERT_DIR" ]; then
    (umask 077; mkdir -p "${CERT_DIR}")
    log_info "Created ${CERT_DIR}"
fi

# These need to get set so that they get filled into the service correctly.
export CERT_LOCATION=$(readlink -f ${CERT_DIR}/$CERT_FILENAME)
export KEY_LOCATION=$(readlink -f ${CERT_DIR}/$KEY_FILENAME)

confirm_inputs "CERT_LOCATION" "KEY_LOCATION"

if [ ! -e "${CERT_DIR}/root_ca.crt" ]; then
    step ca root "${CERT_DIR}/root_ca.crt"
fi

if [ ! -f "$CERT_LOCATION" ] || [ ! -f "$KEY_LOCATION" ]; then
    hostname=$(hostname -s)
    ip_address=$(ip -4 addr show dev eth0 | awk '/inet /{print $2}' | cut -d/ -f1)
    step ca certificate "$hostname" \
        "${CERT_DIR}/cert.pem" "${CERT_DIR}/key.pem" \
        --san "$hostname" \
        --san "$hostname.john-stream.com" \
        --san "$ip_address" \
        --provisioner admin
fi

echo "" >&2
echo -e "${GREEN}=== Cert information ===${NC}" >&2
openssl x509 -noout -subject -issuer -ext extendedKeyUsage -ext subjectAltName -enddate -in "$CERT_LOCATION"

SERVICE_FILE="cert-renewer.service"
TIMER_FILE="cert-renewer.timer"
REPO_URL_BASE=https://gitea.john-stream.com/john/soteria/raw/branch/main/
SERVICE_TEMPLATE_URL="${REPO_URL_BASE}systemd/${SERVICE_FILE}"
TIMER_TEMPLATE_URL="${REPO_URL_BASE}systemd/${TIMER_FILE}"

echo "" >&2
echo -e "${GREEN}=== Installing rotation services ===${NC}" >&2
install_unit ${SERVICE_TEMPLATE_URL}
install_unit ${TIMER_TEMPLATE_URL}

echo "" >&2
echo -e "${GREEN}=== Reloading services ===${NC}" >&2
systemctl daemon-reload
systemctl enable --now "${TIMER_FILE}" "${SERVICE_FILE}"
systemctl list-unit-files $SERVICE_FILE $TIMER_FILE