package logfile

import (
	"encoding/csv"
	"fmt"
	"os"
	"strconv"
	"time"

	"github.com/go-flucky/flucky/pkg/types"
)

type csvLogfile struct {
	logfile string
}

func (cl *csvLogfile) Read() ([]*types.MeasuredValue, error) {
	if _, err := os.Stat(cl.logfile); os.IsNotExist(err) {
		return nil, fmt.Errorf("%v: %v", errorLogfileNotFound, cl.logfile)
	}

	f, err := os.Open(cl.logfile)
	if err != nil {
		return nil, fmt.Errorf("%v: %v", errorLogfileOpen, cl.logfile)
	}
	defer f.Close()

	r := csv.NewReader(f)
	records, err := r.ReadAll()
	if err != nil {
		return nil, fmt.Errorf("%v %v: %v", errorLogfileDecode, cl.logfile, err)
	}

	measuredValues := make([]*types.MeasuredValue, 0)

	for _, record := range records {

		// ValueType
		valueType, err := types.SelectMeasuredValueType(record[1])
		if err != nil {
			return nil, fmt.Errorf("%v %v: %v", errorParseFloat, record[1], err)
		}

		// Value
		value, err := strconv.ParseFloat(record[2], 64)
		if err != nil {
			return nil, fmt.Errorf("%v %v: %v", errorParseFloat, record[2], err)
		}

		// Times
		times := make([]time.Time, 0)
		for _, i := range []int{3, 4} {
			time, err := time.Parse(timeFormat, record[i])
			if err != nil {
				return nil, fmt.Errorf("%v %v: %v", errorParseTime, record[i], err)
			}
			times = append(times, time)
		}

		measuredValue := &types.MeasuredValue{
			ID:        record[0],
			ValueType: *valueType,
			Value:     value,
			FromDate:  times[0],
			TillDate:  times[1],
			SensorID:  record[5],
		}

		// Creation date
		creationDate, err := time.Parse(timeFormat, record[6])
		if err != nil {
			return nil, fmt.Errorf("%v %v: %v", errorParseTime, record[6], err)
		}
		measuredValue.CreationDate = &creationDate

		if record[7] != "null" {
			updateDate, err := time.Parse(timeFormat, record[7])
			if err != nil {
				return nil, fmt.Errorf("%v %v: %v", errorParseTime, record[7], err)
			}
			measuredValue.UpdateDate = &updateDate
		}

		measuredValues = append(measuredValues, measuredValue)

	}

	return measuredValues, nil

}

func (cl *csvLogfile) Write(measuredValues []*types.MeasuredValue) error {
	f, err := os.Create(cl.logfile)
	if err != nil {
		return fmt.Errorf("%v: %v", errorLogfileCreate, cl.logfile)
	}
	defer f.Close()

	writeCreationDate(measuredValues)

	w := csv.NewWriter(f)

	for _, measuredValue := range measuredValues {

		record := []string{
			measuredValue.ID,
			fmt.Sprintf("%v", measuredValue.ValueType),
			fmt.Sprintf("%v", measuredValue.Value),
			measuredValue.FromDate.Format(timeFormat),
			measuredValue.TillDate.Format(timeFormat),
			measuredValue.SensorID,
		}

		if measuredValue.CreationDate != nil {
			record = append(record, measuredValue.CreationDate.Format(timeFormat))
		} else {
			record = append(record, "null")
		}

		if measuredValue.UpdateDate != nil {
			record = append(record, measuredValue.UpdateDate.Format(timeFormat))
		} else {
			record = append(record, "null")
		}

		w.Write(record)
	}

	w.Flush()

	return nil
}