package logger

import (
	"encoding/json"
	"fmt"
	"io"
	"io/ioutil"
	"os"
	"sync"
	"time"

	"git.cryptic.systems/fh-trier/go-flucky/pkg/internal/errutils"

	"git.cryptic.systems/fh-trier/go-flucky/pkg/types"
)

type FileLogger struct {
	LogFiles map[LogValue][]string `json:"logfiles"`
	writer   io.Writer
}

func (fl *FileLogger) AddLogFile(logfile string, logValue LogValue) {
	fl.LogFiles[logValue] = append(fl.LogFiles[logValue], logfile)
}

func (fl *FileLogger) GetHumidities(fromDate *time.Time, tillDate *time.Time, sensorNameOrUUID *[]string) ([]*types.Humidity, error) {
	return nil, nil
}
func (fl *FileLogger) GetTemperatures(from *time.Time, till *time.Time, sensorIDs []string) ([]*types.Temperature, error) {
	cachedTemperatures := []*types.Temperature{}

	// iterate over all configured temperature logfiles
	for _, logfile := range fl.LogFiles[LogTemperature] {

		// skip logfile if not exists
		if _, err := os.Stat(logfile); os.IsNotExist(err) {
			return nil, fmt.Errorf("Logfile %v not exists", logfile)
		}

		loggedTemperatures := []*types.Temperature{}

		f, err := os.Open(logfile)
		if err != nil {
			return nil, fmt.Errorf("Can not open %v: %v", logfile, err)
		}
		defer f.Close()

		decoder := json.NewDecoder(f)
		err = decoder.Decode(&loggedTemperatures)
		if err != nil {
			return nil, fmt.Errorf("Can not decode temperatures from logfile %v: %v", logfile, err)
		}

		// sort all redundant values out
		for _, loggedTemperature := range loggedTemperatures {
			found := false
			for _, cachedTemperature := range cachedTemperatures {
				if cachedTemperature.TemperatureID == loggedTemperature.TemperatureID {
					found = true
					break
				}
			}
			if !found {
				cachedTemperatures = append(cachedTemperatures, loggedTemperature)
			}
		}
	}

	// // sort out all temperatures which are not mesured by sensor id
	// for i, cachedTemperature := range cachedTemperatures {
	// 	found := false
	// 	for _, sensorID := range sensorIDs {
	// 		if cachedTemperature.SensorID == sensorID {
	// 			found = true
	// 			break
	// 		}
	// 	}
	// 	if !found {
	// 		cachedTemperatures = append(cachedTemperatures[:i], cachedTemperatures[i+1:]...)
	// 	}
	// }

	// // sort out all temperatures which are before from date
	// if from != nil {
	// 	for i, cachedTemperature := range cachedTemperatures {
	// 		if cachedTemperature.TemperatureDate.Before(*from) {
	// 			cachedTemperatures = append(cachedTemperatures[:i], cachedTemperatures[i+1:]...)
	// 		}
	// 	}
	// }

	// // sort out all temperatures which are after till date
	// if till != nil {
	// 	for i, cachedTemperature := range cachedTemperatures {
	// 		if cachedTemperature.TemperatureDate.After(*till) {
	// 			cachedTemperatures = append(cachedTemperatures[:i], cachedTemperatures[i+1:]...)
	// 		}
	// 	}
	// }

	return cachedTemperatures, nil
}

func (fl *FileLogger) LogHumidities(humidities []*types.Humidity) error {
	countLogfiles := len(fl.LogFiles[LogHumidity])
	wg := sync.WaitGroup{}
	wg.Add(countLogfiles)

	errChan := make(chan error)

	for _, logfile := range fl.LogFiles[LogHumidity] {
		go func(humidities []*types.Humidity, logfile string) {
			defer wg.Done()

			// read existing humidities as bytes
			bytes, err := ioutil.ReadFile(logfile)
			if err != nil {
				errChan <- err
				return
			}

			// convert bytes into humidities
			logHumidities := []*types.Humidity{}
			err = json.Unmarshal(bytes, &logHumidities)
			if err != nil {
				errChan <- err
				return
			}

			// append new humidities with exsisting humidities from logfile
			logHumidities = append(logHumidities, humidities...)

			// convert humidities into json file
			bytes, err = json.MarshalIndent(logHumidities, "", " ")
			err = json.Unmarshal(bytes, &logHumidities)
			if err != nil {
				errChan <- err
				return
			}

			ioutil.WriteFile(logfile, bytes, os.ModePerm)

		}(humidities, logfile)
	}

	wg.Wait()

	errList := errutils.CollectErrors(errChan)
	err := errutils.FormatErrors(errList)
	if err != nil {
		return err
	}
	return nil
}

func (fl *FileLogger) LogTemperatures(temperatures []*types.Temperature) error {
	for _, logfile := range fl.LogFiles[LogTemperature] {

		logTemperatures := []*types.Temperature{}

		// open logfile
		f, err := os.OpenFile(logfile, os.O_RDWR, os.ModePerm)
		if err != nil {
			return fmt.Errorf("Can not open file %v: %v", logfile, err)
		}
		defer f.Close()

		// if logfile already exists, read temperatures from logfile
		if _, err := os.Stat(logfile); os.IsExist(err) {
			decoder := json.NewDecoder(f)
			err = decoder.Decode(&logTemperatures)
			if err != nil {
				return fmt.Errorf("Can not decode temperatures from reader")
			}
		}

		// append new temperatures with exsisting humidities from logfile
		logTemperatures = append(logTemperatures, temperatures...)

		// encode temperatures
		encoder := json.NewEncoder(f)
		encoder.SetIndent("", " ")
		err = encoder.Encode(logTemperatures)
		if err != nil {
			return fmt.Errorf("Can not encode temperatures for the writer")
		}
	}

	return nil
}

func NewFileLogger(w io.Writer) *FileLogger {
	return &FileLogger{
		writer: w,
	}
}