#!/bin/bash
#
# Dune Weaver - Autohotspot Setup
#
# Sets up the autohotspot system so the Pi creates a "Dune Weaver" WiFi
# hotspot when no known network is available. Users connect to the hotspot
# and configure WiFi through the Dune Weaver app.
#
# DNS redirect for captive portal is handled by NetworkManager's built-in
# dnsmasq (via dnsmasq-shared.d config), not a separate dnsmasq instance.
#
# Run: bash wifi/setup-wifi.sh
# Or:  dw wifi setup
#

set -e

# Colors
RED='\033[0;31m'
GREEN='\033[0;32m'
YELLOW='\033[1;33m'
BLUE='\033[0;34m'
NC='\033[0m'

# Determine script and project directories
SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
PROJECT_DIR="$(dirname "$SCRIPT_DIR")"

HOTSPOT_CON_NAME="DuneWeaver-Hotspot"
HOTSPOT_SSID="Dune Weaver"
HOTSPOT_IP="10.42.0.1/24"
IFACE="wlan0"
NM_DNSMASQ_DIR="/etc/NetworkManager/dnsmasq-shared.d"

print_step() {
    echo -e "\n${BLUE}==>${NC} ${GREEN}$1${NC}"
}

print_success() {
    echo -e "${GREEN}$1${NC}"
}

print_warning() {
    echo -e "${YELLOW}Warning:${NC} $1"
}

print_error() {
    echo -e "${RED}Error:${NC} $1"
}

# Check prerequisites
check_prereqs() {
    print_step "Checking prerequisites..."

    # Check for NetworkManager
    if ! command -v nmcli &>/dev/null; then
        print_error "NetworkManager (nmcli) not found. This requires Pi OS Trixie or later."
        exit 1
    fi

    # Check for wlan0
    if ! nmcli dev show "$IFACE" &>/dev/null; then
        print_warning "WiFi interface '$IFACE' not found. Hotspot may not work."
    fi

    print_success "Prerequisites OK"
}

# Create the NetworkManager hotspot connection profile
create_hotspot_profile() {
    print_step "Creating hotspot connection profile..."

    # Remove existing profile if present
    if nmcli con show "$HOTSPOT_CON_NAME" &>/dev/null; then
        echo "Removing existing hotspot profile..."
        sudo nmcli con delete "$HOTSPOT_CON_NAME" 2>/dev/null || true
    fi

    # Read app name from state.json if available
    local ssid="$HOTSPOT_SSID"
    local state_file="$PROJECT_DIR/state.json"
    if [ -f "$state_file" ]; then
        local app_name
        app_name=$(python3 -c "import json; print(json.load(open('$state_file')).get('app_name', ''))" 2>/dev/null || true)
        if [ -n "$app_name" ]; then
            ssid="$app_name"
            echo "Using app name from state.json: $ssid"
        fi
    fi

    # Create the hotspot profile (open network, no password)
    sudo nmcli con add type wifi ifname "$IFACE" mode ap con-name "$HOTSPOT_CON_NAME" \
        ssid "$ssid" autoconnect no \
        ipv4.method shared ipv4.addresses "$HOTSPOT_IP"

    print_success "Hotspot profile created: SSID='$ssid', IP=${HOTSPOT_IP%/*}"
}

# Install DNS redirect config for captive portal
install_dns_redirect() {
    print_step "Installing DNS redirect for captive portal..."

    # NetworkManager's shared mode runs its own dnsmasq.
    # Configs in dnsmasq-shared.d/ are loaded automatically when a shared
    # connection is active. This redirects ALL DNS to the Pi's hotspot IP,
    # triggering captive portal detection on phones/tablets.
    sudo mkdir -p "$NM_DNSMASQ_DIR"
    sudo cp "$SCRIPT_DIR/dnsmasq-hotspot.conf" "$NM_DNSMASQ_DIR/dune-weaver-captive.conf"

    print_success "DNS redirect installed at $NM_DNSMASQ_DIR/dune-weaver-captive.conf"
}

# Copy autohotspot script and service
install_configs() {
    print_step "Installing autohotspot script..."

    # Copy autohotspot script
    sudo cp "$SCRIPT_DIR/autohotspot" /usr/local/bin/autohotspot
    sudo chmod +x /usr/local/bin/autohotspot
    echo "Installed /usr/local/bin/autohotspot"

    print_success "Autohotspot script installed"
}

# Install and enable the systemd service and timer
install_service() {
    print_step "Installing autohotspot service and timer..."

    # Boot service: runs once at startup with 30s scan
    sudo cp "$SCRIPT_DIR/autohotspot.service" /etc/systemd/system/autohotspot.service

    # Periodic check: runs every 60s to detect WiFi drops and recover
    sudo cp "$SCRIPT_DIR/autohotspot-check.service" /etc/systemd/system/autohotspot-check.service
    sudo cp "$SCRIPT_DIR/autohotspot-check.timer" /etc/systemd/system/autohotspot-check.timer

    sudo systemctl daemon-reload
    sudo systemctl enable autohotspot.service
    sudo systemctl enable --now autohotspot-check.timer

    print_success "autohotspot.service and autohotspot-check.timer installed and enabled"
}

# Main
main() {
    echo -e "${GREEN}Dune Weaver Autohotspot Setup${NC}"
    echo ""

    check_prereqs
    create_hotspot_profile
    install_dns_redirect
    install_configs
    install_service

    echo ""
    echo -e "${GREEN}============================================${NC}"
    echo -e "${GREEN}   Autohotspot Setup Complete!${NC}"
    echo -e "${GREEN}============================================${NC}"
    echo ""
    echo "On next boot, the Pi will:"
    echo "  1. Scan for known WiFi networks (30s timeout)"
    echo "  2. If found → connect normally"
    echo "  3. If not found → create a '$(nmcli -t -f 802-11-wireless.ssid con show "$HOTSPOT_CON_NAME" 2>/dev/null | cut -d: -f2 || echo "$HOTSPOT_SSID")' hotspot"
    echo ""
    echo "A periodic check runs every 60 seconds to:"
    echo "  - Fall back to hotspot if WiFi drops"
    echo "  - Reconnect to known WiFi when it becomes available"
    echo ""
    echo "Users can connect to the hotspot and open the Dune Weaver app"
    echo "to configure WiFi credentials."
    echo ""
    echo "Commands:"
    echo "  dw wifi status   — Show current WiFi mode"
    echo "  dw wifi hotspot  — Manually switch to hotspot mode"
    echo "  dw wifi scan     — Scan for available networks"
}

main "$@"