package modem

import (
	"fmt"
	"io"
	"log"
	"os"
	"os/exec"
	"strings"
	"sync"
	"time"

	"github.com/CGSG-2021-AE4/modem-test/api/modem/at"
	"github.com/CGSG-2021-AE4/modem-test/api/modem/gpio"
	"github.com/CGSG-2021-AE4/modem-test/api/modem/gps"
	"github.com/CGSG-2021-AE4/modem-test/api/modem/internet"
	"github.com/CGSG-2021-AE4/modem-test/api/modem/sms"
)

type ModemData struct {
	Port string `json:"Port"`
	gps.Data
}

type modem struct {
	// Internal values
	logger *log.Logger
	mutex  sync.Mutex

	// Serial values
	baudrate   int
	deviceName string
	port       at.Port

	// Gpio values
	onOffPin gpio.Pin // For turning on and off

	// Other values
	lastUpdateTime time.Time

	// GPS
	gps gps.Gps

	// Internet connection
	ic internet.Conn

	// Sms and calls
	sms sms.Sms
}

type Modem interface {
	Init() error
	IsConnected() bool
	Update() error
	GetData() ModemData

	PowerOn() error
	PowerOff() error

	// Access to SMS, GPS, AT interfaces mostly for debug
	At() at.Port  // Send
	Gps() gps.Gps // Update, GetData, GetStatus
	Sms() sms.Sms // Send, ReadNew

	io.Closer
}

func New(logger *log.Logger) Modem {
	return &modem{
		logger:   logger,
		baudrate: 115200,
		onOffPin: gpio.New(log.New(logger.Writer(), "gpio", log.LstdFlags), 6),

		lastUpdateTime: time.Now(),
	}
}

func (m *modem) Init() error {
	m.mutex.Lock()
	defer m.mutex.Unlock()

	// Turn module on
	m.logger.Println("=============================== Turn on module")
	if err := m.onOffPin.Init(); err != nil {
		return fmt.Errorf("gpio pin init: %w", err)
	}

	// Search
	m.logger.Println("=============================== Search")
	// Soft search
	if err := m.searchPort(true); err != nil {
		return fmt.Errorf("soft port search: %w", err)
	}
	// Wide search
	if m.port == nil {
		if err := m.searchPort(false); err != nil {
			return fmt.Errorf("not soft port search: %w", err)
		}
	}
	if m.port == nil {
		return fmt.Errorf("no port is detected")
	}

	// Connect
	m.logger.Println("=============================== Connect")
	if err := m.connect(); err != nil {
		return fmt.Errorf("connect: %w", err)
	}

	// Init submodules
	submodulesLogger := m.logger.Writer() // FOR more logs
	// submodulesLogger := io.Discard // FOR less logs

	m.logger.Println("=============================== Init submodules")
	m.ic = internet.New(log.New(submodulesLogger, "modem-internet : ", log.LstdFlags), m.port)
	if err := m.ic.Init(); err != nil {
		m.logger.Printf("\x1b[38;2;255;0;0mInternet: %s\x1b[38;2;255;255;255m\n", err.Error())
	} else {
		m.logger.Println("\x1b[38;2;0;255;0mInternet OK\x1b[38;2;255;255;255m")
	}

	m.sms = sms.New(log.New(submodulesLogger, "modem-sms : ", log.LstdFlags), m.port)
	if err := m.sms.Init(); err != nil {
		m.logger.Printf("\x1b[38;2;255;0;0mSMS: %s\x1b[38;2;255;255;255m\n", err.Error())
	} else {
		m.logger.Println("\x1b[38;2;0;255;0mSMS OK\x1b[38;2;255;255;255m")
	}

	m.gps = gps.New(log.New(submodulesLogger, "modem-gps : ", log.LstdFlags), m.port)
	if err := m.gps.Init(); err != nil {
		m.logger.Printf("\x1b[38;2;255;0;0mgps init %w\x1b[38;2;255;255;255m\n", err)
	} else {
		m.logger.Println("\x1b[38;2;0;255;0mGPS OK\x1b[38;2;255;255;255m")
	}

	// Tests
	// GPS works fine but almost always there is no signal
	// m.logger.Println("=============================== Test")
	// if err := m.testGPS(); err != nil {
	// 	return fmt.Errorf("testGPS: %w", err)
	// }

	return nil
}

func (m *modem) Update() error {
	m.mutex.Lock()
	defer m.mutex.Unlock()

	if !m.IsConnected() {
		m.logger.Println("No connection to module")
		return nil
	}
	m.logger.Println("Update", m.gps)
	if err := m.gps.Update(); err != nil {
		m.logger.Println("gps update:", err.Error())
	}
	// Read new messages

	return nil
}

func (m *modem) GetData() ModemData {
	m.mutex.Lock()
	defer m.mutex.Unlock()

	return ModemData{
		Port: m.port.GetName(),
		Data: m.gps.GetData(),
	}
}

func (m *modem) PowerOn() error {
	m.onOffPin.PowerOn() // DEBUG do not want to wait 30 seconds
	return nil
}

func (m *modem) PowerOff() error {
	_, err := m.At().Send("AT+CPOF")
	return err
}

func (m *modem) Sms() sms.Sms {
	return m.sms
}

func (m *modem) Gps() gps.Gps {
	return m.gps
}

func (m *modem) At() at.Port {
	return m.port
}

func (m *modem) Close() error { // I can't return error so I log it
	m.mutex.Lock()
	defer m.mutex.Unlock()

	if err := m.sms.Close(); err != nil {
		m.logger.Printf("\x1b[38;2;255;0;0mclose sms error: %s\x1b[38;2;255;255;255m\n", err.Error())
	}

	if err := m.port.Close(); err != nil {
		m.logger.Printf("\x1b[38;2;255;0;0mclose serial port error: %s\x1b[38;2;255;255;255m\n", err.Error())
	}
	if err := m.onOffPin.Close(); err != nil {
		m.logger.Printf("\x1b[38;2;255;0;0mclose gpio pin error: %s\x1b[38;2;255;255;255m\n", err.Error())
	}
	if err := m.ic.Close(); err != nil {
		m.logger.Printf("\x1b[38;2;255;0;0mclose internet connection error: %s\x1b[38;2;255;255;255m\n", err.Error())
	}

	return nil
}

///////////// Private functions

func (m *modem) connect() error {
	if m.port == nil {
		return fmt.Errorf("port is not defined")
	}
	return m.port.Connect()
}

func (m *modem) disconnect() error {
	if m.port == nil {
		return fmt.Errorf("port is not defined")
	}
	return m.port.Disconnect()
}

func (m *modem) IsConnected() bool {
	if m.port != nil {
		return m.port.IsConnected()
	}
	return false
}

func (m *modem) testGPS() error {
	m.logger.Println("Testing GPS")

	if err := m.Update(); err != nil {
		return fmt.Errorf("update: %w", err)
	}

	m.logger.Println("Current coords:", m.getShortInfo())
	return nil
}

// Difference: I do not set \n at the end of string
func (m *modem) getShortInfo() string {
	d := m.gps.GetData()
	return fmt.Sprintf("%f,%s,%f,%s", d.Latitude, d.LatitudeIndicator, d.Longitude, d.LongitudeIndicator)
}

func (m *modem) saveGPS(path string) error {
	f, err := os.OpenFile(path, os.O_APPEND|os.O_WRONLY|os.O_CREATE, 0600)
	if err != nil {
		return fmt.Errorf("open file: %w", err)
	}
	defer f.Close()

	if _, err = f.WriteString(m.getShortInfo()); err != nil {
		return fmt.Errorf("write file: %W", err)
	}
	return nil
}

// Short way to send command
func (m *modem) printCmd(cmd string) {
	if resp, err := m.port.Send(cmd); err != nil {
		m.logger.Println("FAILED TO SEND REQ", cmd, ":", err.Error())
	} else {
		_ = resp
		// m.logger.Println("CMD", cmd, ":", resp)
	}
}

// Some required commands before checking port
func (m *modem) setupPort() error {
	// Reset input
	if err := m.port.SerialPort().ResetInputBuffer(); err != nil {
		return fmt.Errorf("reset input buffer: %w", err)
	}
	// Reset output
	if err := m.port.SerialPort().ResetOutputBuffer(); err != nil {
		return fmt.Errorf("reset output buffer: %w", err)
	}

	// These commands ensure that correct modes are set
	m.printCmd("ATE0")         // Sometimes enables echo mode
	m.printCmd("AT+CGPSFTM=0") // Sometimes does not turn off nmea
	m.printCmd("AT+CMEE=2")    // Turn on errors describtion

	return nil
}

func (m *modem) checkPort(portName string) (outErr error) {
	defer func() {
		if outErr != nil { // Clear port if there is error
			m.port = nil
		}
	}()

	// Check device for existance
	if _, err := os.Stat(portName); err != nil {
		return fmt.Errorf("device does not exist")
	}

	// Check serial connection
	// Connect
	m.port = at.New(m.logger, portName, m.baudrate)
	if err := m.port.Connect(); err != nil {
		return fmt.Errorf("connect: %w", err)
	}
	defer m.port.Disconnect() // Do not bother about errors...

	// To filter dead ports
	if _, err := m.port.Send("AT"); err != nil {
		return fmt.Errorf("ping error: %w", err)
	}

	if err := m.setupPort(); err != nil {
		return fmt.Errorf("setup port: %w", err)
	}

	// Ping
	m.logger.Println("Ping...")
	if err := m.ping(); err != nil {
		return fmt.Errorf("ping error: %w", err)
	}
	m.logger.Println("\x1b[38;2;0;255;0mOK\x1b[38;2;255;255;255m")

	// Check model
	m.logger.Println("Check model...")
	resp, err := m.port.Send("AT+CGMM")
	if err != nil {
		return fmt.Errorf("get model: %w", err)
	}
	if !resp.Check() {
		return fmt.Errorf("get model: error response: %s", resp)
	}
	model := strings.Split(resp.String(), "\n")[0]
	if err != nil {
		return fmt.Errorf("get model: %w", err)
	}
	rightModel := "SIMCOM_SIM7600E-H"
	// m.logger.Printf("[% x]\n [% x]", []byte("SIMCOM_SIM7600E-H"), []byte(model))
	if len(model) >= len(rightModel) && model[:len(rightModel)] != rightModel {
		return fmt.Errorf("invalid modem model: %s", model)
	}
	m.logger.Println("\x1b[38;2;0;255;0mOK\x1b[38;2;255;255;255m")
	return nil
}

func (m *modem) searchPort(isSoft bool) error {
	// Get ports
	ports := []string{"ttyUSB1", "ttyUSB2", "ttyUSB3"}
	if !isSoft {
		ps, err := getTtyDevices()
		if err != nil {
			fmt.Errorf("get serial devices: %w", err)
		}
		ports = ps
	}

	// Check ports
SearchLoop:
	for _, p := range ports {
		m.logger.Printf("Checking port %s ...\n", p)

		if err := m.checkPort("/dev/" + p); err != nil {
			m.logger.Printf("\x1b[38;2;255;0;0mCheck failed: %s\x1b[38;2;255;255;255m\n", err.Error())
			continue SearchLoop
		}

		m.logger.Print("Found modem on port: ", p)
		m.port = at.New(m.logger, "/dev/"+p, m.baudrate)
		return nil
	}
	return nil
}

func (m *modem) ping() error {
	resp, err := m.port.Send("AT")
	if err != nil {
		return fmt.Errorf("AT request: %w", err)
	}
	if !resp.Check() {
		return fmt.Errorf("AT request: error response: %s", resp)
	}
	return nil
}

func getTtyDevices() ([]string, error) {
	// Get ports
	/**/
	out, err := exec.Command("ls", "--", "/dev/tty[!0-9]*").Output()
	if err != nil {
		return nil, fmt.Errorf("execute ls command: %w", err)
	}
	ports := strings.Split(string(out), "\n")
	return ports, nil
}

/*
	TODOs:
		maybe to store read/write buf in obj
	QUESTIONS:
		JSON why you clamp
*/

/*
 */