package main

import (
	"context"
	"fmt"
	"kettuRay/core"
	"sync"
	"time"

	"github.com/getlantern/systray"
	"github.com/google/uuid"
	"github.com/wailsapp/wails/v2/pkg/runtime"
)

// VpnConfigItem is the frontend-facing config model (includes transient ping info).
type VpnConfigItem struct {
	ID           string `json:"id"`
	Name         string `json:"name"`
	Link         string `json:"link"`
	ProtocolType string `json:"protocolType"`
	Ping         string `json:"ping"`
	PingColor    string `json:"pingColor"`
}

// App is the Wails application binding.
type App struct {
	ctx     context.Context
	manager *core.CoreManager
	cfgMgr  *core.ConfigManager
	settings *core.AppSettings

	mu              sync.Mutex
	configs         []core.VpnConfig
	pingResults     map[string]core.PingResult
	selectedConfigID string

	// Auto-reconnect state
	isReconnecting   bool
	reconnectFailLog []time.Time

	// Tray
	trayToggleItem *systray.MenuItem
}

func NewApp() *App {
	return &App{
		pingResults: make(map[string]core.PingResult),
	}
}

func (a *App) startup(ctx context.Context) {
	a.ctx = ctx

	var err error
	a.manager, err = core.NewCoreManager()
	if err != nil {
		runtime.LogFatalf(ctx, "Failed to init core manager: %v", err)
		return
	}

	a.cfgMgr, err = core.NewConfigManager()
	if err != nil {
		runtime.LogFatalf(ctx, "Failed to init config manager: %v", err)
		return
	}

	a.settings = core.LoadSettings()

	configs, _ := a.cfgMgr.LoadConfigs()
	if configs != nil {
		a.configs = configs
	}

	a.manager.OnStateChanged = func(state core.ConnectionState) {
		s := state.String()
		runtime.EventsEmit(a.ctx, "state-changed", s)
		a.updateTrayState(s)
		a.sendStateNotification(state)

		if state == core.Error && a.settings.AutoReconnect && !a.isReconnecting {
			go a.tryAutoReconnect()
		}
		if state == core.Connected {
			a.mu.Lock()
			a.isReconnecting = false
			a.reconnectFailLog = nil
			a.mu.Unlock()
		}
	}

	a.manager.OnLog = func(source, message string) {
		runtime.EventsEmit(a.ctx, "log", source, message)
	}

	// Restore last selected config
	if a.settings.LastConfigID != "" {
		a.mu.Lock()
		a.selectedConfigID = a.settings.LastConfigID
		a.mu.Unlock()
	} else if len(a.configs) > 0 {
		a.mu.Lock()
		a.selectedConfigID = a.configs[0].ID
		a.mu.Unlock()
	}

	// Ping all on startup in background
	if len(a.configs) > 0 {
		go a.pingAll()
	}

	// Auto-connect on startup
	if a.settings.AutoConnect {
		go func() {
			time.Sleep(500 * time.Millisecond)
			a.mu.Lock()
			id := a.selectedConfigID
			a.mu.Unlock()
			if id != "" {
				a.connectByID(id)
			}
		}()
	}

	a.settings.ApplyStartupRegistry()

	// System tray
	a.setupTray()

	// Global hotkey Win+Alt+V
	a.registerHotkey()
}

// sendStateNotification emits a custom notification event to the frontend.
func (a *App) sendStateNotification(state core.ConnectionState) {
	a.mu.Lock()
	cfg := a.findSelectedConfig()
	reconnecting := a.isReconnecting
	a.mu.Unlock()

	name := ""
	if cfg != nil {
		name = cfg.DisplayName()
	}

	switch state {
	case core.Connected:
		msg := "VPN Connected"
		if name != "" {
			msg += " — " + name
		}
		runtime.EventsEmit(a.ctx, "notification", msg, "#4CAF50")
	case core.Disconnected:
		if !reconnecting {
			runtime.EventsEmit(a.ctx, "notification", "VPN Disconnected", "#E53935")
		}
	case core.Error:
		if !a.settings.AutoReconnect {
			runtime.EventsEmit(a.ctx, "notification", "VPN Connection Error", "#E53935")
		}
	}
}

func (a *App) findSelectedConfig() *core.VpnConfig {
	for i := range a.configs {
		if a.configs[i].ID == a.selectedConfigID {
			return &a.configs[i]
		}
	}
	return nil
}

func (a *App) shutdown(ctx context.Context) {
	if a.manager != nil {
		a.manager.Close()
	}
	systray.Quit()
}

// --- Configs ---

func (a *App) GetConfigs() []VpnConfigItem {
	a.mu.Lock()
	defer a.mu.Unlock()

	items := make([]VpnConfigItem, 0, len(a.configs))
	for _, c := range a.configs {
		ping := a.pingResults[c.ID]
		display := ""
		color := "#666"
		if ping.Ms >= 0 && ping.Color != "" {
			display = fmt.Sprintf("%dms", ping.Ms)
			color = ping.Color
		}
		items = append(items, VpnConfigItem{
			ID:           c.ID,
			Name:         c.DisplayName(),
			Link:         c.Link,
			ProtocolType: c.ProtocolType(),
			Ping:         display,
			PingColor:    color,
		})
	}
	return items
}

// AddConfig adds a new VPN config. Returns error message or "" on success.
func (a *App) AddConfig(link string) string {
	if link == "" {
		return "Link cannot be empty"
	}
	if core.TryParseLink(link) == nil {
		return "Invalid or unsupported link format"
	}

	cfg := core.VpnConfig{
		ID:   uuid.NewString(),
		Name: core.ExtractNameFromLink(link),
		Link: link,
	}

	a.mu.Lock()
	a.configs = append(a.configs, cfg)
	a.mu.Unlock()

	_ = a.cfgMgr.SaveConfigs(a.configs)

	// Ping new config in background
	go func() {
		result := core.PingConfig(&cfg)
		a.mu.Lock()
		a.pingResults[cfg.ID] = result
		a.mu.Unlock()
		display := ""
		if result.Ms >= 0 {
			display = fmt.Sprintf("%dms", result.Ms)
		}
		runtime.EventsEmit(a.ctx, "ping-update", cfg.ID, display, result.Color)
	}()

	return ""
}

func (a *App) DeleteConfig(id string) {
	a.mu.Lock()
	for i, c := range a.configs {
		if c.ID == id {
			a.configs = append(a.configs[:i], a.configs[i+1:]...)
			delete(a.pingResults, id)
			break
		}
	}
	if a.selectedConfigID == id {
		a.selectedConfigID = ""
	}
	a.mu.Unlock()

	_ = a.cfgMgr.SaveConfigs(a.configs)
}

func (a *App) SetSelectedConfig(id string) {
	a.mu.Lock()
	a.selectedConfigID = id
	a.mu.Unlock()

	a.settings.LastConfigID = id
	_ = a.settings.Save()
}

func (a *App) GetSelectedConfigID() string {
	a.mu.Lock()
	defer a.mu.Unlock()
	return a.selectedConfigID
}

// --- Connection ---

func (a *App) Connect(id string) {
	go a.connectByID(id)
}

func (a *App) connectByID(id string) {
	a.mu.Lock()
	var link string
	for _, c := range a.configs {
		if c.ID == id {
			link = c.Link
			break
		}
	}
	a.mu.Unlock()

	if link == "" {
		runtime.EventsEmit(a.ctx, "toast", "Config not found", true)
		return
	}

	if err := a.manager.Connect(link); err != nil {
		runtime.EventsEmit(a.ctx, "toast", "Connection failed: "+err.Error(), true)
	}
}

func (a *App) Disconnect() {
	go a.manager.Disconnect()
}

func (a *App) GetState() string {
	if a.manager == nil {
		return "Disconnected"
	}
	return a.manager.State.String()
}

// --- Ping ---

func (a *App) PingAll() {
	go a.pingAll()
}

func (a *App) pingAll() {
	a.mu.Lock()
	configs := make([]core.VpnConfig, len(a.configs))
	copy(configs, a.configs)
	a.mu.Unlock()

	var wg sync.WaitGroup
	for _, c := range configs {
		c := c
		wg.Add(1)
		go func() {
			defer wg.Done()
			result := core.PingConfig(&c)
			a.mu.Lock()
			a.pingResults[c.ID] = result
			a.mu.Unlock()
			display := ""
			if result.Ms >= 0 {
				display = fmt.Sprintf("%dms", result.Ms)
			}
			runtime.EventsEmit(a.ctx, "ping-update", c.ID, display, result.Color)
		}()
	}
	wg.Wait()
}

// --- Settings ---

func (a *App) GetSettings() *core.AppSettings {
	return a.settings
}

func (a *App) SaveSettings(runOnStartup, autoConnect, autoReconnect bool) {
	a.settings.RunOnStartup = runOnStartup
	a.settings.AutoConnect = autoConnect
	a.settings.AutoReconnect = autoReconnect
	_ = a.settings.Save()
	a.settings.ApplyStartupRegistry()
}

// --- Window ---

func (a *App) ResizeWindow(width, height int) {
	runtime.WindowSetSize(a.ctx, width, height)
}

// --- Auto-reconnect ---

const reconnectFailWindow = 30 * time.Second
const reconnectFailThreshold = 5

func (a *App) tryAutoReconnect() {
	a.mu.Lock()
	now := time.Now()
	fresh := make([]time.Time, 0, len(a.reconnectFailLog)+1)
	for _, t := range a.reconnectFailLog {
		if now.Sub(t) < reconnectFailWindow {
			fresh = append(fresh, t)
		}
	}
	fresh = append(fresh, now)
	a.reconnectFailLog = fresh
	count := len(fresh)
	id := a.selectedConfigID
	a.mu.Unlock()

	if count >= reconnectFailThreshold {
		a.mu.Lock()
		a.reconnectFailLog = nil
		a.isReconnecting = false
		a.mu.Unlock()
		runtime.EventsEmit(a.ctx, "notification", "Auto-reconnect stopped", "#E53935")
		return
	}

	a.mu.Lock()
	a.isReconnecting = true
	a.mu.Unlock()

	runtime.EventsEmit(a.ctx, "notification", fmt.Sprintf("Reboot: attempt %d...", count), "#FDD835")
	time.Sleep(1 * time.Second)

	if id != "" {
		a.connectByID(id)
	}
}