package uhf

import (
	"errors"
	"fmt"
	"net"
	"sync"
	"sync/atomic"
	"time"

	"go.uber.org/zap"
	"wails-app/internal/global"
)

type TCPReader struct {
	IP        string
	Port      int
	conn      net.Conn
	connected atomic.Bool
	buffer    []byte // 内部拼包缓冲区（关键修复）
	ioMu      sync.Mutex
}

// 实现 Reader 接口的继电器方法（不再panic）
func (t *TCPReader) CloseRelay1(validTime byte) error {
	frame := buildRelayFrame(0x0077, RELAY_OP_CLOSE, validTime)
	return t.sendRelayCommand("open", 1, validTime, frame)
}

func (t *TCPReader) ReleaseRelay1() error {
	frame := buildRelayFrame(0x0077, RELAY_OP_RELEASE, 0)
	return t.sendRelayCommand("release", 1, 0, frame)
}

func (t *TCPReader) CloseRelay2(validTime byte) error {
	frame := buildRelayFrame(0x0078, RELAY_OP_CLOSE, validTime)
	return t.sendRelayCommand("close", 2, validTime, frame)
}

func (t *TCPReader) ReleaseRelay2() error {
	frame := buildRelayFrame(0x0078, RELAY_OP_RELEASE, 0)
	return t.sendRelayCommand("release", 2, 0, frame)
}

func NewTCPReader(ip string, port int) *TCPReader {
	return &TCPReader{
		IP:   ip,
		Port: port,
	}
}

func (t *TCPReader) Connect() error {
	t.ioMu.Lock()
	defer t.ioMu.Unlock()
	addr := net.JoinHostPort(t.IP, fmt.Sprintf("%d", t.Port))
	conn, err := net.DialTimeout("tcp", addr, 5*time.Second)
	if err != nil {
		t.connected.Store(false)
		t.logWarn("UHF TCP 连接失败", zap.Error(err))
		return err
	}
	t.conn = conn
	t.connected.Store(true)
	t.logInfo("UHF TCP 连接成功")
	return nil
}

func (t *TCPReader) Disconnect() error {
	t.ioMu.Lock()
	defer t.ioMu.Unlock()
	if t.conn != nil {
		_ = t.conn.Close()
	}
	t.connected.Store(false)
	t.buffer = nil
	t.logInfo("UHF TCP 连接已关闭")
	return nil
}

func (t *TCPReader) IsConnected() bool {
	return t.connected.Load()
}

func (t *TCPReader) SendData(data []byte) error {
	t.ioMu.Lock()
	defer t.ioMu.Unlock()
	return t.sendDataLocked(data)
}

func (t *TCPReader) sendDataLocked(data []byte) error {
	if !t.connected.Load() {
		return errors.New("TCP未连接")
	}
	_, err := t.conn.Write(data)
	if err != nil {
		t.connected.Store(false)
		t.logWarn("UHF TCP 写入失败", zap.String("packet_hex", fmt.Sprintf("%x", data)), zap.Error(err))
	}
	return err
}

// ==============================
// 🔥 关键修复：TCP 自动拼包，按协议变长帧提取（标签帧25字节，继电器应答9字节等）
// ==============================
func (t *TCPReader) ReadData() ([]byte, error) {
	t.ioMu.Lock()
	defer t.ioMu.Unlock()
	return t.readDataLocked()
}

func (t *TCPReader) readDataLocked() ([]byte, error) {
	if !t.connected.Load() {
		return nil, errors.New("TCP未连接")
	}

	// 读超时，防止永久阻塞
	t.conn.SetReadDeadline(time.Now().Add(3 * time.Second))

	buf := make([]byte, 1024)
	n, err := t.conn.Read(buf)
	if err != nil {
		if netErr, ok := err.(net.Error); ok && netErr.Timeout() {
			return nil, ErrReadTimeout
		}
		t.connected.Store(false)
		t.logWarn("UHF TCP 读取失败", zap.Error(err))
		return nil, err
	}

	// 加入缓冲区
	t.buffer = append(t.buffer, buf[:n]...)
	t.logDebug("UHF TCP 收到数据块",
		zap.Int("packet_bytes", n),
		zap.Int("buffered_bytes", len(t.buffer)),
		zap.String("packet_hex", fmt.Sprintf("%x", buf[:n])),
	)

	frame, rest, ok := extractUHFFrame(t.buffer)
	t.buffer = rest
	if !ok {
		if len(t.buffer) > 0 {
			return nil, ErrIncompleteFrame
		}
		return nil, ErrReadTimeout
	}
	return frame, nil
}

func (t *TCPReader) SendAndRecv(data []byte) ([]byte, error) {
	t.ioMu.Lock()
	defer t.ioMu.Unlock()
	if err := t.sendDataLocked(data); err != nil {
		return nil, err
	}
	t.conn.SetReadDeadline(time.Now().Add(3 * time.Second))
	return t.readDataLocked()
}

// isRelayAckFor 判断响应帧是否为对应指令的应答（设备回显命令字）。
func isRelayAckFor(response, frame []byte) bool {
	return len(response) >= 7 && response[0] == 0xCF &&
		response[2] == frame[2] && response[3] == frame[3]
}

func (t *TCPReader) sendRelayCommand(action string, relay int, validTime byte, frame []byte) error {
	t.logInfo("UHF TCP 道闸指令下发",
		zap.String("action", action),
		zap.Int("relay", relay),
		zap.Uint8("valid_time_seconds", validTime),
		zap.String("packet_hex", fmt.Sprintf("%x", frame)),
	)
	t.ioMu.Lock()
	defer t.ioMu.Unlock()
	if err := t.sendDataLocked(frame); err != nil {
		t.logWarn("UHF TCP 道闸指令失败", zap.String("action", action), zap.Error(err))
		return err
	}
	// 等待设备应答（回显命令字）。期间收到的标签上报帧放回缓冲区交还读循环。
	for attempt := 0; attempt < 3; attempt++ {
		response, err := t.readDataLocked()
		if err != nil {
			break
		}
		if isRelayAckFor(response, frame) {
			status := "unknown"
			if len(response) >= 7 {
				status = fmt.Sprintf("0x%02x", response[5])
			}
			t.logInfo("UHF TCP 道闸指令收到响应",
				zap.String("action", action),
				zap.Int("relay", relay),
				zap.String("status", status),
				zap.String("response_hex", fmt.Sprintf("%x", response)),
			)
			if len(response) >= 7 && response[5] != 0x00 {
				return fmt.Errorf("道闸指令被设备拒绝: 状态码 %s", status)
			}
			return nil
		}
		t.buffer = append(append(make([]byte, 0, len(response)+len(t.buffer)), response...), t.buffer...)
	}
	err := fmt.Errorf("道闸指令未收到设备应答（帧已发出）")
	t.logWarn("UHF TCP 道闸指令失败", zap.String("action", action), zap.Error(err))
	return err
}

func (t *TCPReader) logInfo(message string, fields ...zap.Field) {
	if global.GVA_LOG == nil {
		return
	}
	fields = append([]zap.Field{zap.String("tcp_address", net.JoinHostPort(t.IP, fmt.Sprintf("%d", t.Port)))}, fields...)
	global.GVA_LOG.Info(message, fields...)
}

func (t *TCPReader) logDebug(message string, fields ...zap.Field) {
	if global.GVA_LOG == nil {
		return
	}
	fields = append([]zap.Field{zap.String("tcp_address", net.JoinHostPort(t.IP, fmt.Sprintf("%d", t.Port)))}, fields...)
	global.GVA_LOG.Debug(message, fields...)
}

func (t *TCPReader) logWarn(message string, fields ...zap.Field) {
	if global.GVA_LOG == nil {
		return
	}
	fields = append([]zap.Field{zap.String("tcp_address", net.JoinHostPort(t.IP, fmt.Sprintf("%d", t.Port)))}, fields...)
	global.GVA_LOG.Warn(message, fields...)
}