package main

import (
	"flag"
	"fmt"
	"log"
	"os"
	"strconv"
	"time"

	"github.com/hashicorp/logutils"
)

func getEnvFloat64(env string, def float64) (val float64) {
	osVal := os.Getenv(env)

	if osVal == "" {
		return def
	}

	var err error
	if val, err = strconv.ParseFloat(osVal, 64); err != nil {
		log.Fatalf("[ERROR] Unable to parse floating point number from environment variable (%s): %v", env, err)
	}
	return
}

func getEnvInt(env string, def int) (ret int) {
	val := os.Getenv(env)

	if val == "" {
		return def
	}

	ret, err := strconv.Atoi(val)
	if err != nil {
		log.Fatalf("[ERROR] Environment variable is not of numeric type: %v\n", env)
	}

	return
}

func getEnvString(env, def string) (val string) {
	val = os.Getenv(env)

	if val == "" {
		return def
	}

	return
}

func getEnvBool(env string, def bool) (val bool) {
	osVal := os.Getenv(env)

	if osVal == "" {
		return def
	}

	var err error
	if val, err = strconv.ParseBool(osVal); err != nil {
		log.Fatalf("[ERROR] Environment variable is not of boolean type: %v\n", env)
	}

	return
}

func setLogLevel(l int) {
	switch {
	case l <= 20:
		config.Log.SetMinLevel(logutils.LogLevel("ERROR"))
	case l > 20 && l <= 40:
		config.Log.SetMinLevel(logutils.LogLevel("WARNING"))
	case l > 40 && l <= 60:
		config.Log.SetMinLevel(logutils.LogLevel("INFO"))
	case l > 60 && l <= 80:
		config.Log.SetMinLevel(logutils.LogLevel("DEBUG"))
	case l > 80:
		config.Log.SetMinLevel(logutils.LogLevel("TRACE"))
	}
}

func initialize() {
	var (
		tz  string
		dt  string
		err error
	)

	flag.IntVar(&config.LogLevel,
		"log",
		getEnvInt("LOG_LEVEL", 0),
		"(LOG_LEVEL) Set the log verbosity.",
	)
	flag.Float64Var(&config.SunRiseSet.Latitude,
		"latitude",
		getEnvFloat64("LATITUDE", 38.749020),
		"(LATITUDE) Latitude for the sunset/sunrise calculation.",
	)
	flag.Float64Var(&config.SunRiseSet.Longitude,
		"longitude",
		getEnvFloat64("LONGITUDE", -90.521360),
		"(LONGITUDE) Longitude for the sunrise/sunset calculation.",
	)
	flag.StringVar(&tz,
		"timezone",
		getEnvString("TIMEZONE", "America/Chicago"),
		"(TIMEZONE) Timezone for the sunrise/sunset calculation.",
	)
	flag.StringVar(&dt,
		"date",
		getEnvString("DATE", time.Now().Format(config.TimeFormat)),
		"(DATE) Date to use for sunrise/sunset calculation.",
	)
	flag.BoolVar(&config.NextSunrise,
		"next-sunrise",
		getEnvBool("SUNRISE", false),
		"(NEXT) Return the number of seconds until the next sunrise.",
	)
	flag.BoolVar(&config.NextSunset,
		"next-sunset",
		getEnvBool("SUNSET", false),
		"(NEXT) Return the number of seconds until the next sunrise.",
	)
	flag.StringVar(&config.Host,
		"host",
		getEnvString("HOST", ""),
		"(HOST) Hostname or IP address of device.",
	)
	flag.IntVar(&config.DeviceID,
		"device-id",
		getEnvInt("DEVICE_ID", 0),
		"(DEVICE_ID) For devices with multiple switchable elements, the\ndevice-id is used to identify the switch port.\nIDs start at 0.",
	)
	flag.BoolVar(&config.GetState,
		"get-state",
		getEnvBool("GET_STATE", false),
		"(ON) Get the power state of the device.",
	)
	flag.BoolVar(&config.On,
		"on",
		getEnvBool("ON", false),
		"(ON) Turn the device on.",
	)
	flag.BoolVar(&config.Off,
		"off",
		getEnvBool("OFF", false),
		"(OFF) Turn the device off.",
	)
	flag.Parse()

	setLogLevel(config.LogLevel)
	log.SetOutput(config.Log)

	// check to make sure options were formatted correctly and can be parsed
	config.CalculateDate, err = time.Parse(config.TimeFormat, dt)
	if err != nil {
		runError(fmt.Sprintf("Unable to parse time: %v\n", err))
	}
	config.TimeZone, err = time.LoadLocation(tz)
	if err != nil {
		runError(fmt.Sprintf("Unable to parse time zone: %v\n", err))
	}

	// check to see if the program was called correctly
	if config.On && config.Off {
		runError("Can not set '-on' and '-off' at the same time.")
	}
	if config.Host == "" && (config.On || config.Off || config.GetState) {
		runError("Must supply '-host' with '-on', '-off', '-get-state'.")
	}
	if config.NextSunrise && config.NextSunset {
		runError("Can not set '-next-sunrise' and '-next-sunset' at the same time.")
	}

	// Get timezone offset
	_, tzOffset := config.CalculateDate.In(config.TimeZone).Zone()
	config.SunRiseSet.UtcOffset = float64(tzOffset / 60 / 60)
}

func runError(errorMsg string) {
	flag.PrintDefaults()
	fmt.Printf("\n\n")
	fmt.Printf("[ERROR] %s\n", errorMsg)
	os.Exit(1)
}