package parking

import (
	"errors"
	"fmt"
	"sync"
	"time"

	"go.uber.org/zap"
	"wails-app/internal/dao"
	"wails-app/internal/global"
	incidentService "wails-app/internal/modules/incident/service"
)

const defaultGateValidTime byte = 2

var incidentSvc = incidentService.NewIncidentService()

// GateCommandContext 道闸指令上下文（用于指令流水审计）。
type GateCommandContext struct {
	Source     string // passage / manual / test
	OperatorID uint
	SessionID  uint
}

// GateController 统一道闸设备控制接口，具体协议由设备模块实现。
type GateController interface {
	OpenGate(deviceCode string, validTime byte) error
	CloseGate(deviceCode string, validTime byte) error
	IsGateConnected(deviceCode string) bool
}

// GateDeviceOption 是工作台可见的安全设备信息，不包含串口、IP 等连接参数。
type GateDeviceOption struct {
	DeviceCode   string `json:"device_code"`
	DeviceName   string `json:"device_name"`
	ChannelID    uint   `json:"channel_id"`
	ChannelCode  string `json:"channel_code"`
	ChannelName  string `json:"channel_name"`
	Direction    string `json:"direction"`
	ParkingLotID uint   `json:"parking_lot_id"`
	Connected    bool   `json:"connected"`
	Simulated    bool   `json:"simulated"`
}

// GateRuntimeStatus 表示统一控制器中的设备实时状态。
type GateRuntimeStatus struct {
	Connected bool
	Simulated bool
}

// SimulatedGateController 用于无硬件环境联调，只记录指令，不访问串口或网络设备。
type SimulatedGateController struct {
	mu         sync.RWMutex
	lastAction map[string]string
}

// NewSimulatedGateController 创建模拟道闸控制器。
func NewSimulatedGateController() *SimulatedGateController {
	return &SimulatedGateController{lastAction: make(map[string]string)}
}

func (c *SimulatedGateController) record(deviceCode, action string) error {
	if deviceCode == "" {
		return errors.New("道闸设备编码不能为空")
	}
	c.mu.Lock()
	c.lastAction[deviceCode] = action
	c.mu.Unlock()
	if global.GVA_LOG != nil {
		global.GVA_LOG.Warn("模拟道闸指令", zap.String("device_code", deviceCode), zap.String("action", action), zap.Time("time", time.Now()))
	}
	return nil
}

// OpenGate 模拟开闸。
func (c *SimulatedGateController) OpenGate(deviceCode string, _ byte) error {
	return c.record(deviceCode, "open")
}

// CloseGate 模拟关闸。
func (c *SimulatedGateController) CloseGate(deviceCode string, _ byte) error {
	return c.record(deviceCode, "close")
}

// IsGateConnected 在模拟模式下将所有有效设备编码视为在线。
func (c *SimulatedGateController) IsGateConnected(deviceCode string) bool {
	return deviceCode != ""
}

func (c *SimulatedGateController) isSimulator() bool {
	return true
}

var (
	gateControllerMu sync.RWMutex
	gateController   GateController
)

// SetGateController 注入设备控制实现，避免停车业务反向依赖具体设备协议。
func SetGateController(controller GateController) {
	gateControllerMu.Lock()
	defer gateControllerMu.Unlock()
	gateController = controller
}

func currentGateController() GateController {
	gateControllerMu.RLock()
	defer gateControllerMu.RUnlock()
	return gateController
}

// GetGateRuntimeStatus 返回设备在当前控制器中的实时连接状态。
func GetGateRuntimeStatus(deviceCode string) GateRuntimeStatus {
	controller := currentGateController()
	if controller == nil || deviceCode == "" {
		return GateRuntimeStatus{}
	}
	status := GateRuntimeStatus{Connected: controller.IsGateConnected(deviceCode)}
	if simulator, ok := controller.(interface{ isSimulator() bool }); ok {
		status.Simulated = simulator.isSimulator()
	}
	return status
}

// OpenGateByDeviceCode 通过统一控制器开闸。
func (s *PassageService) OpenGateByDeviceCode(deviceCode string, validTime byte) error {
	if deviceCode == "" {
		return errors.New("道闸设备编码不能为空")
	}
	controller := currentGateController()
	if controller == nil {
		return errors.New("道闸控制器未初始化")
	}
	if validTime == 0 {
		validTime = defaultGateValidTime
	}
	return controller.OpenGate(deviceCode, validTime)
}

// CloseGateByDeviceCode 通过统一控制器关闸。
func (s *PassageService) CloseGateByDeviceCode(deviceCode string, validTime byte) error {
	if deviceCode == "" {
		return errors.New("道闸设备编码不能为空")
	}
	controller := currentGateController()
	if controller == nil {
		return errors.New("道闸控制器未初始化")
	}
	if validTime == 0 {
		validTime = defaultGateValidTime
	}
	return controller.CloseGate(deviceCode, validTime)
}

// OpenGateWithContext 开闸并记录指令流水（所有开闸路径的审计入口），返回流水 ID。
func (s *PassageService) OpenGateWithContext(ctx GateCommandContext, deviceCode string, validTime byte) (uint, error) {
	return s.runGateCommand(ctx, "open", deviceCode, validTime)
}

// CloseGateWithContext 关闸并记录指令流水，返回流水 ID。
func (s *PassageService) CloseGateWithContext(ctx GateCommandContext, deviceCode string, validTime byte) (uint, error) {
	return s.runGateCommand(ctx, "close", deviceCode, validTime)
}

// runGateCommand 执行道闸指令并写指令流水（best-effort，流水失败不影响指令结果）。
func (s *PassageService) runGateCommand(ctx GateCommandContext, action, deviceCode string, validTime byte) (uint, error) {
	if ctx.Source == "" {
		ctx.Source = "passage"
	}
	start := time.Now()
	var err error
	if action == "open" {
		err = s.OpenGateByDeviceCode(deviceCode, validTime)
	} else {
		err = s.CloseGateByDeviceCode(deviceCode, validTime)
	}

	rec := incidentService.GateCommandRecord{
		DeviceCode: deviceCode,
		Action:     action,
		Source:     ctx.Source,
		OperatorID: ctx.OperatorID,
		SessionID:  ctx.SessionID,
		DurationMs: time.Since(start).Milliseconds(),
	}
	if err != nil {
		rec.Result = incidentService.CommandFailed
		rec.ErrorMessage = err.Error()
	} else {
		rec.Result = incidentService.CommandSuccess
	}
	// 设备名称快照（查询失败不影响指令结果）
	var device dao.UHFReader
	if global.GVA_DB != nil {
		if qerr := global.GVA_DB.Where("device_code = ?", deviceCode).First(&device).Error; qerr == nil {
			rec.DeviceName = device.DeviceName
		}
	}
	return incidentSvc.RecordGateCommand(rec), err
}

// ListGateDevices 返回已启用且已绑定通道的道闸设备。
func (s *PassageService) ListGateDevices() ([]GateDeviceOption, error) {
	if global.GVA_DB == nil {
		return nil, errors.New("数据库未初始化")
	}
	var readers []dao.UHFReader
	if err := global.GVA_DB.Preload("Channel").
		Where("is_active = ? AND channel_id > 0", true).
		Order("device_name ASC").Find(&readers).Error; err != nil {
		return nil, err
	}

	options := make([]GateDeviceOption, 0, len(readers))
	for _, reader := range readers {
		if reader.Channel == nil {
			continue
		}
		parkingLotID := reader.Channel.ParkingLotID
		if parkingLotID == 0 {
			parkingLotID = reader.ParkingLotID
		}
		runtimeStatus := GetGateRuntimeStatus(reader.DeviceCode)
		options = append(options, GateDeviceOption{
			DeviceCode: reader.DeviceCode, DeviceName: reader.DeviceName,
			ChannelID: reader.ChannelID, ChannelCode: reader.Channel.ChannelCode,
			ChannelName: reader.Channel.ChannelName, Direction: reader.Channel.Direction,
			ParkingLotID: parkingLotID,
			Connected:    runtimeStatus.Connected,
			Simulated:    runtimeStatus.Simulated,
		})
	}
	return options, nil
}

func gateOperationError(action, deviceCode string, err error) error {
	return fmt.Errorf("道闸%s失败（设备 %s）: %w", action, deviceCode, err)
}