package statusupdate

import (
	"encoding/csv"
	"errors"
	"strings"
	"sync"

	"src.dualinventive.com/go/lib/dilog"
)

// StatusDecoder decodes cp3000 status messages
type StatusDecoder struct {
	mu              sync.RWMutex
	prevUpdateState *StatusUpdate
	resetFields     StatUpdateField
	logger          dilog.Logger
}

// NewStatusDecoder creates a new status decoder. The initial parameter is already set.
func NewStatusDecoder(logger dilog.Logger, fields StatUpdateField) *StatusDecoder {
	return &StatusDecoder{
		prevUpdateState: &StatusUpdate{
			Fields: fields,
		},
		resetFields: fields,
		logger:      logger,
	}
}

// Decode decodes the cp3000 status message
func (d *StatusDecoder) Decode(args []string) error {
	r := csv.NewReader(strings.NewReader(args[1]))
	r.Comma = ','
	r.LazyQuotes = true
	record, err := r.Read()
	if err != nil {
		return err
	}
	if len(record) != 22 {
		return errors.New("wrong record count for statusupdate")
	}

	// This decoder is based on the original TCP-server implemetation,
	//  a status message can contains all fields but some may miss.
	//  no errors are checked since the checksum is complete and we know
	//  we have 22 fields at this point, this MUST be a generic status update
	//        ---- SAME AS LEGACY ---- >:-D
	s := &StatusUpdate{}

	// IMPORTANT the order here is important
	records := decodeState(d.logger, s, StatUpdateAll, record)
	records = decodeWCPUState(d.logger, s, StatUpdateAll, records)
	records = decodeAutocal(d.logger, s, StatUpdateAll, records)
	records = decodeRMS(d.logger, s, StatUpdateAll, records)
	records = decodeBA(d.logger, s, StatUpdateAll, records)
	records = decodeBatSelected(d.logger, s, StatUpdateAll, records)
	records = decodeBatt1Level(d.logger, s, StatUpdateAll, records)
	records = decodeBatt2Level(d.logger, s, StatUpdateAll, records)
	records = decodeTempOnBoard(d.logger, s, StatUpdateAll, records)
	records = decodeTempNTC(d.logger, s, StatUpdateAll, records)
	records = decodeGSM(d.logger, s, StatUpdateAll, records)
	decodeGPS(d.logger, s, StatUpdateAll, records)

	// The GPS is updated every 30 minutes we want to send all sensor
	//  every once in a while, so we abuse the GPS-time :-)
	if d.prevUpdateState.GPSTime != s.GPSTime {
		s.Fields = d.resetFields
	}
	d.mu.Lock()
	d.prevUpdateState = s
	d.mu.Unlock()
	return nil
}

// StatusUpdate returns the last known status update
func (d *StatusDecoder) StatusUpdate() *StatusUpdate {
	d.mu.RLock()
	defer d.mu.RUnlock()
	return d.prevUpdateState
}