package wpasupplicant

import (
	"fmt"
	"log"
	"time"

	"github.com/godbus/dbus/v5"
	"github.com/nemunaire/repeater/internal/wifi/backend"
)

// WPABackend implements the WiFiBackend interface for wpa_supplicant
type WPABackend struct {
	conn           *dbus.Conn
	wpasupplicant  dbus.BusObject
	iface          *WPAInterface
	signalMonitor  *SignalMonitor
	interfaceName  string
	currentNetwork dbus.ObjectPath
}

// NewWPABackend creates a new wpa_supplicant backend instance
func NewWPABackend() *WPABackend {
	return &WPABackend{}
}

// Initialize initializes the wpa_supplicant backend with the given interface name
func (b *WPABackend) Initialize(interfaceName string) error {
	b.interfaceName = interfaceName
	var err error

	// Connect to D-Bus
	b.conn, err = dbus.SystemBus()
	if err != nil {
		return fmt.Errorf("failed to connect to D-Bus: %v", err)
	}

	// Get wpa_supplicant root object
	b.wpasupplicant = b.conn.Object(Service, dbus.ObjectPath(RootPath))

	// Get interface path for the given interface name
	interfacePath, err := b.getInterfacePath(interfaceName)
	if err != nil {
		return fmt.Errorf("failed to get interface for %s: %v", interfaceName, err)
	}

	b.iface = NewWPAInterface(b.conn, interfacePath)

	return nil
}

// getInterfacePath gets or creates the wpa_supplicant Interface object path
func (b *WPABackend) getInterfacePath(interfaceName string) (dbus.ObjectPath, error) {
	var interfacePath dbus.ObjectPath

	// Try to get existing interface
	err := b.wpasupplicant.Call(Service+".GetInterface", 0, interfaceName).Store(&interfacePath)
	if err == nil {
		return interfacePath, nil
	}

	// Interface doesn't exist, create it
	args := map[string]dbus.Variant{
		"Ifname": dbus.MakeVariant(interfaceName),
	}

	err = b.wpasupplicant.Call(Service+".CreateInterface", 0, args).Store(&interfacePath)
	if err != nil {
		return "", fmt.Errorf("failed to create interface: %v", err)
	}

	return interfacePath, nil
}

// Close closes the D-Bus connection
func (b *WPABackend) Close() error {
	if b.conn != nil {
		b.conn.Close()
	}
	return nil
}

// ScanNetworks triggers a network scan
func (b *WPABackend) ScanNetworks() error {
	err := b.iface.Scan("active")
	if err != nil {
		return fmt.Errorf("failed to trigger scan: %v", err)
	}
	return nil
}

// GetOrderedNetworks returns networks sorted by signal strength in backend-agnostic format
func (b *WPABackend) GetOrderedNetworks() ([]backend.BackendNetwork, error) {
	// Get BSS list
	bssPaths, err := b.iface.GetBSSs()
	if err != nil {
		return nil, fmt.Errorf("failed to get BSSs: %v", err)
	}

	var networks []backend.BackendNetwork
	seenSSIDs := make(map[string]bool)

	// Iterate through BSSs and collect network info
	for _, bssPath := range bssPaths {
		bss := NewBSS(b.conn, bssPath)
		props, err := bss.GetProperties()
		if err != nil {
			continue
		}

		ssid := string(props.SSID)
		if ssid == "" || seenSSIDs[ssid] {
			continue
		}
		seenSSIDs[ssid] = true

		// Get BSSID string
		bssidStr, err := bss.GetBSSIDString()
		if err != nil {
			bssidStr = ""
		}

		// Convert to backend-agnostic format
		backendNet := backend.BackendNetwork{
			SSID:         ssid,
			SignalDBm:    props.Signal,
			SecurityType: props.DetermineSecurityType(),
			BSSID:        bssidStr,
			Frequency:    props.Frequency,
		}

		networks = append(networks, backendNet)
	}

	// Sort by signal strength (descending)
	// Note: This is a simple bubble sort for demonstration
	// In production, use sort.Slice
	for i := 0; i < len(networks); i++ {
		for j := i + 1; j < len(networks); j++ {
			if networks[j].SignalDBm > networks[i].SignalDBm {
				networks[i], networks[j] = networks[j], networks[i]
			}
		}
	}

	return networks, nil
}

// IsScanning checks if a scan is currently in progress
func (b *WPABackend) IsScanning() (bool, error) {
	return b.iface.GetScanning()
}

// Connect connects to a WiFi network
func (b *WPABackend) Connect(ssid, password string) error {
	// Best-effort lookup of existing networks, used both to avoid creating
	// duplicate entries for the same SSID and to re-enable other entries
	// after SelectNetwork's "disable all others" side-effect. If listing
	// fails, fall back to plain AddNetwork — saving still works.
	existingNetworks, err := b.iface.GetNetworks()
	if err != nil {
		log.Printf("wpa_supplicant: failed to list configured networks: %v", err)
		existingNetworks = nil
	}

	var networkPath dbus.ObjectPath
	createdNew := false

	for _, p := range existingNetworks {
		net := NewNetwork(b.conn, p)
		netSSID, err := net.GetSSID()
		if err != nil || netSSID != ssid {
			continue
		}
		networkPath = p
		break
	}

	if networkPath == "" {
		// Create network configuration
		config := make(map[string]interface{})
		config["ssid"] = ssid // Raw SSID string, no quotes

		if password != "" {
			// For WPA/WPA2-PSK networks
			config["psk"] = password // Raw password string, no quotes
		} else {
			// For open networks
			config["key_mgmt"] = "NONE"
		}

		networkPath, err = b.iface.AddNetwork(config)
		if err != nil {
			return fmt.Errorf("failed to add network: %v", err)
		}
		createdNew = true
	}

	// Store current network path
	b.currentNetwork = networkPath

	// Select (connect to) the network. Note: SelectNetwork disables every
	// other configured network as a side-effect.
	if err := b.iface.SelectNetwork(networkPath); err != nil {
		if createdNew {
			b.iface.RemoveNetwork(networkPath)
		}
		return fmt.Errorf("failed to select network: %v", err)
	}

	// Re-enable previously configured networks so SelectNetwork's side-effect
	// doesn't mark them all as disabled in the persisted config.
	for _, p := range existingNetworks {
		if p == networkPath {
			continue
		}
		if err := b.iface.EnableNetwork(p); err != nil {
			log.Printf("wpa_supplicant: failed to re-enable network %s: %v", p, err)
		}
	}

	// Save the configuration to persist it across reboots. Requires
	// update_config=1 in the wpa_supplicant.conf wpa_supplicant was started
	// with, and that file being writable by the wpa_supplicant process.
	if err := b.iface.SaveConfig(); err != nil {
		log.Printf("wpa_supplicant: SaveConfig failed: %v", err)
	} else {
		log.Printf("wpa_supplicant: configuration saved for SSID %q", ssid)
	}

	return nil
}

// Disconnect disconnects from the current WiFi network
func (b *WPABackend) Disconnect() error {
	// Disconnect from current network
	if err := b.iface.Disconnect(); err != nil {
		return fmt.Errorf("failed to disconnect: %v", err)
	}

	b.currentNetwork = ""

	return nil
}

// GetConnectionState returns the current WiFi connection state
func (b *WPABackend) GetConnectionState() (backend.ConnectionState, error) {
	state, err := b.iface.GetState()
	if err != nil {
		return backend.StateDisconnected, err
	}
	return mapWPAState(state), nil
}

// GetConnectedSSID returns the SSID of the currently connected network
func (b *WPABackend) GetConnectedSSID() string {
	// Get current BSS
	bssPath, err := b.iface.GetCurrentBSS()
	if err != nil || bssPath == "/" {
		return ""
	}

	// Get BSS object
	bss := NewBSS(b.conn, bssPath)
	ssid, err := bss.GetSSIDString()
	if err != nil {
		return ""
	}

	return ssid
}

// StartEventMonitoring starts monitoring WiFi events
func (b *WPABackend) StartEventMonitoring(callbacks backend.EventCallbacks) error {
	// Create signal monitor
	b.signalMonitor = NewSignalMonitor(b.conn, b.iface)

	// Start monitoring
	return b.signalMonitor.Start(callbacks)
}

// StopEventMonitoring stops monitoring WiFi events
func (b *WPABackend) StopEventMonitoring() {
	if b.signalMonitor != nil {
		b.signalMonitor.Stop()
	}
}

// Wait for scan to complete (helper method)
func (b *WPABackend) waitForScanComplete(timeout time.Duration) error {
	start := time.Now()
	for {
		if time.Since(start) > timeout {
			return fmt.Errorf("scan timeout")
		}

		scanning, err := b.iface.GetScanning()
		if err != nil {
			return err
		}

		if !scanning {
			return nil
		}

		time.Sleep(100 * time.Millisecond)
	}
}