package common

import (
	"bytes"
	"encoding/json"
	"fmt"
	"github.com/benbjohnson/clock"
	"github.com/go-yaml/yaml"
	"github.com/patrickmn/go-cache"
	"github.com/sirupsen/logrus"
	"io/ioutil"
	"os"
	"path"
	"path/filepath"
	"strings"
)

const (
	logFileName   = "stream.log"
	etc_dir       = "/etc/"
	data_dir      = "/data/"
	log_dir       = "/log/"
	StreamConf    = "kuiper.yaml"
	KuiperBaseKey = "KuiperBaseKey"
)

var (
	Log       *logrus.Logger
	Config    *XStreamConf
	IsTesting bool
	Clock     clock.Clock
	logFile   *os.File
)

func LoadConf(confName string) ([]byte, error) {
	confDir, err := GetConfLoc()
	if err != nil {
		return nil, err
	}

	file := confDir + confName
	b, err := ioutil.ReadFile(file)
	if err != nil {
		return nil, err
	}
	return b, nil
}

type XStreamConf struct {
	Debug          bool `yaml:"debug"`
	Port           int  `yaml:"port"`
	Prometheus     bool `yaml:"prometheus"`
	PrometheusPort int  `yaml:"prometheusPort"`
}

func init() {
	Log = logrus.New()
	Log.SetFormatter(&logrus.TextFormatter{
		DisableColors: true,
		FullTimestamp: true,
	})
	Log.Debugf("init with args %s", os.Args)
	for _, arg := range os.Args {
		if strings.HasPrefix(arg, "-test.") {
			IsTesting = true
			break
		}
	}
	if IsTesting {
		Log.Debugf("running in testing mode")
		Clock = clock.NewMock()
	} else {
		Clock = clock.New()
	}
}

func InitConf() {
	b, err := LoadConf(StreamConf)
	if err != nil {
		Log.Fatal(err)
	}
	var cfg map[string]XStreamConf
	if err := yaml.Unmarshal(b, &cfg); err != nil {
		Log.Fatal(err)
	}

	if c, ok := cfg["basic"]; !ok {
		Log.Fatal("No basic config in kuiper.yaml")
	} else {
		Config = &c
	}

	if !Config.Debug {
		logDir, err := GetLoc(log_dir)
		if err != nil {
			Log.Fatal(err)
		}
		file := logDir + logFileName
		logFile, err := os.OpenFile(file, os.O_CREATE|os.O_WRONLY|os.O_APPEND, 0666)
		if err == nil {
			Log.Out = logFile
		} else {
			Log.Infof("Failed to log to file, using default stderr")
		}
	} else {
		Log.SetLevel(logrus.DebugLevel)
	}
}

type KeyValue interface {
	Open() error
	Close() error
	Set(key string, value interface{}) error
	Replace(key string, value interface{}) error
	Get(key string) (interface{}, bool)
	Delete(key string) error
	Keys() (keys []string, err error)
}

type SimpleKVStore struct {
	path string
	c    *cache.Cache
}

var stores = make(map[string]*SimpleKVStore)

func GetSimpleKVStore(path string) *SimpleKVStore {
	if s, ok := stores[path]; ok {
		return s
	} else {
		c := cache.New(cache.NoExpiration, 0)
		if _, err := os.Stat(path); os.IsNotExist(err) {
			os.MkdirAll(path, os.ModePerm)
		}
		sStore := &SimpleKVStore{path: path + "/stores.data", c: c}
		stores[path] = sStore
		return sStore
	}
}

func (m *SimpleKVStore) Open() error {
	if _, err := os.Stat(m.path); os.IsNotExist(err) {
		return nil
	}
	if e := m.c.LoadFile(m.path); e != nil {
		return e
	}
	return nil
}

func (m *SimpleKVStore) Close() error {
	e := m.saveToFile()
	m.c.Flush() //Delete all of the values from memory.
	return e
}

func (m *SimpleKVStore) saveToFile() error {
	if e := m.c.SaveFile(m.path); e != nil {
		return e
	}
	return nil
}

func (m *SimpleKVStore) Set(key string, value interface{}) error {
	if m.c == nil {
		return fmt.Errorf("cache %s has not been initialized yet", m.path)
	}
	if err := m.c.Add(key, value, cache.NoExpiration); err != nil {
		return err
	}
	return m.saveToFile()
}

func (m *SimpleKVStore) Replace(key string, value interface{}) error {
	if m.c == nil {
		return fmt.Errorf("cache %s has not been initialized yet", m.path)
	}
	m.c.Set(key, value, cache.NoExpiration)
	return m.saveToFile()
}

func (m *SimpleKVStore) Get(key string) (interface{}, bool) {
	return m.c.Get(key)
}

func (m *SimpleKVStore) Delete(key string) error {
	if m.c == nil {
		return fmt.Errorf("cache %s has not been initialized yet", m.path)
	}
	if _, found := m.c.Get(key); found {
		m.c.Delete(key)
	} else {
		return fmt.Errorf("%s is not found", key)
	}
	return m.saveToFile()
}

func (m *SimpleKVStore) Keys() (keys []string, err error) {
	if m.c == nil {
		return nil, fmt.Errorf("Cache %s has not been initialized yet.", m.path)
	}
	its := m.c.Items()
	keys = make([]string, 0, len(its))
	for k := range its {
		keys = append(keys, k)
	}
	return keys, nil
}

func PrintMap(m map[string]string, buff *bytes.Buffer) {

	for k, v := range m {
		buff.WriteString(fmt.Sprintf("%s: %s\n", k, v))
	}
}

func CloseLogger() {
	if logFile != nil {
		logFile.Close()
	}
}

func GetConfLoc() (string, error) {
	return GetLoc(etc_dir)
}

func GetDataLoc() (string, error) {
	return GetLoc(data_dir)
}

func GetLoc(subdir string) (string, error) {
	dir, err := os.Getwd()
	if err != nil {
		return "", err
	}

	if base := os.Getenv(KuiperBaseKey); base != "" {
		Log.Infof("Specified Kuiper base folder at location %s.\n", base)
		dir = base
	}

	confDir := dir + subdir
	if _, err := os.Stat(confDir); os.IsNotExist(err) {
		lastdir := dir
		for len(dir) > 0 {
			dir = filepath.Dir(dir)
			if lastdir == dir {
				break
			}
			confDir = dir + subdir
			if _, err := os.Stat(confDir); os.IsNotExist(err) {
				lastdir = dir
				continue
			} else {
				//Log.Printf("Trying to load file from %s", confDir)
				return confDir, nil
			}
		}
	} else {
		//Log.Printf("Trying to load file from %s", confDir)
		return confDir, nil
	}

	return "", fmt.Errorf("conf dir not found, please set KuiperBaseKey program environment variable correctly.")
}

func GetAndCreateDataLoc(dir string) (string, error) {
	dataDir, err := GetDataLoc()
	if err != nil {
		return "", err
	}
	d := path.Join(path.Dir(dataDir), dir)
	if _, err := os.Stat(d); os.IsNotExist(err) {
		err = os.MkdirAll(d, 0755)
		if err != nil {
			return "", err
		}
	}
	return d, nil
}

func ProcessPath(p string) (string, error) {
	if abs, err := filepath.Abs(p); err != nil {
		return "", nil
	} else {
		if _, err := os.Stat(abs); os.IsNotExist(err) {
			return "", err
		}
		return abs, nil
	}
}

/*********** Type Cast Utilities *****/
//TODO datetime type
func ToString(input interface{}) string {
	return fmt.Sprintf("%v", input)
}
func ToInt(input interface{}) (int, error) {
	switch t := input.(type) {
	case float64:
		return int(t), nil
	case int64:
		return int(t), nil
	case int:
		return t, nil
	default:
		return 0, fmt.Errorf("unsupported type %T of %[1]v", input)
	}
}

/*
*   Convert a map into a struct. The output parameter must be a pointer to a struct
*   The struct can have the json meta data
 */
func MapToStruct(input map[string]interface{}, output interface{}) error {
	// convert map to json
	jsonString, err := json.Marshal(input)
	if err != nil {
		return err
	}

	// convert json to struct
	return json.Unmarshal(jsonString, output)
}