package sms

import (
	"fmt"
	"io"
	"log"
	"strings"

	"github.com/CGSG-2021-AE4/modem-test/api/modem/at"
)

type dialer struct {
	logger *log.Logger
	port   at.Port
}

type Dialer interface {
	Init() error
	Send(number, msg string) error
	ReadNew() ([]string, error)
	io.Closer
}

func (d *dialer) Init() error {
	// Ensure serial port
	if !d.port.IsConnected() {
		return fmt.Errorf("serial port is not connected")
	}
	// Ensure text format
	if resp, err := d.port.Send("AT+CMGF=1"); err != nil || !resp.Check() {
		if err != nil {
			return fmt.Errorf("AT+CMGF=1 request: %w", err)
		}
		return fmt.Errorf("failed to set SMS format")
	}
	return nil
}

func (d *dialer) Send(number, msg string) error {
	cmd := fmt.Sprintf("AT+CMGS=\"%s\"\r%s%c", number, msg, 26)
	if resp, err := d.port.Send(cmd); err != nil || !resp.Check() {
		if err != nil {
			return fmt.Errorf("AT+CGMS= request: %w", err)
		}
		if errCode, err := GetError(resp.Bytes()); err != nil {
			return fmt.Errorf("failed to send with SMS error: %s", DecodeError(errCode))
		}
		return fmt.Errorf("failed to send SMS")
	}
	return nil
}

// Reads all new messages
func (d *dialer) ReadNew() ([]string, error) {
	resp, err := d.port.Send("AT+CMGL")
	if err != nil {
		return nil, fmt.Errorf("AT+CMGL request: %w", err)
	}
	msgs := strings.Split(strings.Replace(string(resp), "\r", "", -1), "\n")
	return msgs, nil // TODO
}