package api

import (
	"errors"
	consulapi "github.com/hashicorp/consul/api"
	"os"
)

// Interface to have all signature methods.
type DataStoreRequester interface {
	InitializeDataStoreClient() error
	CheckDataStoreHealth() error
	RequestPUT(string, string) error
	RequestGET(string) (string, error)
	RequestGETS() ([]string, error)
	RequestDELETE(string) error
}

// Consul Struct
type ConsulStruct struct {
	consulClient *consulapi.Client
}

func (c *ConsulStruct) InitializeDataStoreClient() error {
	if os.Getenv("DATASTORE_IP") == "" {
		return errors.New("DATASTORE_IP (consul/cassandra) environment variable not set.")
	}
	config := consulapi.DefaultConfig()
	config.Address = os.Getenv("DATASTORE_IP") + ":8500"

	client, err := consulapi.NewClient(config)
	if err != nil {
		return err
	}
	c.consulClient = client

	return nil
}

func (c *ConsulStruct) CheckDataStoreHealth() error {
	kv := c.consulClient.KV()
	_, _, err := kv.Get("test", nil)
	if err != nil {
		return errors.New("[ERROR] Cannot talk to Consul. Check if it is running/reachable.")
	}
	return nil
}

func (c *ConsulStruct) RequestPUT(key string, value string) error {
	kv := c.consulClient.KV()
	p := &consulapi.KVPair{Key: key, Value: []byte(value)}
	_, err := kv.Put(p, nil)
	if err != nil {
		return err
	}
	return nil
}

func (c *ConsulStruct) RequestGET(key string) (string, error) {
	kv := c.consulClient.KV()
	pair, _, err := kv.Get(key, nil)
	if pair == nil {
		return string("No value found for key."), err
	}
	return string(pair.Value), err

}

func (c *ConsulStruct) RequestGETS() ([]string, error) {
	kv := c.consulClient.KV()
	pairs, _, err := kv.List("", nil)
	if len(pairs) == 0 {
		return []string{"No keys found."}, err
	}

	var res []string

	for _, keypair := range pairs {
		res = append(res, keypair.Key)
	}
	return res, err
}

func (c *ConsulStruct) RequestDELETE(key string) error {
	kv := c.consulClient.KV()
	_, err := kv.Delete(key, nil)
	if err != nil {
		return err
	}
	return nil
}

// TODO(sshank): Place holder to add connection to MUSIC's Cassandra.
type CassandraStruct struct {
	// Add necesary Cassandra client.
}

func (cs *CassandraStruct) InitializeDataStoreClient() error {

	return nil
}

func (cs *CassandraStruct) CheckDataStoreHealth() error {

	return nil
}

func (cs *CassandraStruct) RequestPUT(string, string) error {

	return nil
}

func (cs *CassandraStruct) RequestGET(string) error {
	return nil
}

func (cs *CassandraStruct) RequestGETS() ([]string, error) {
	return []string{""}, nil
}

func (cs *CassandraStruct) RequestDELETE(string) error {
	return nil
}