package etcd

import (
	"context"
	"errors"
	"strings"

	"git.giftfish.de/ston1th/haproxy-lb/pkg/cluster"
	"github.com/go-logr/logr"
	clientv3 "go.etcd.io/etcd/client/v3"
)

type Cluster struct {
	log logr.Logger
	cli *clientv3.Client
	ctx context.Context

	stepdown  chan struct{}
	stop      chan struct{}
	done      chan struct{}
	callbacks cluster.Callbacks

	kvPrefix      string
	id            string
	keyID         string
	session       bool
	sessionCancel func()
	fatal         error
}

func NewCluster(log logr.Logger) cluster.Cluster {
	c := &Cluster{log: log}
	c.Reset()
	return c
}

func (c *Cluster) Reset() {
	c.ctx = context.Background()
	c.stepdown = make(chan struct{}, 1)
	c.stop = make(chan struct{}, 1)
	c.done = make(chan struct{}, 1)
	c.session = false
	c.fatal = nil
}

func (c *Cluster) Get(k string) (v []byte, err error) {
	r, err := c.cli.Get(c.ctx, c.kvPrefix+"/"+k)
	if err != nil {
		return
	}
	if len(r.Kvs) == 0 {
		err = cluster.ErrKeyNotFound
		return
	}
	v = r.Kvs[0].Value
	return
}

func (c *Cluster) GetPrefix(pk string) (m map[string][]byte, err error) {
	r, err := c.cli.Get(c.ctx, c.kvPrefix+"/"+pk, clientv3.WithPrefix())
	if err != nil {
		return
	}
	if len(r.Kvs) == 0 {
		err = cluster.ErrPrefixNotFound
		return
	}
	m = make(map[string][]byte)
	for _, kv := range r.Kvs {
		key := strings.TrimPrefix(string(kv.Key), c.kvPrefix+"/"+pk)
		m[key] = kv.Value
	}
	return
}

func (c *Cluster) Set(k string, v []byte) (err error) {
	_, err = c.cli.Put(c.ctx, c.kvPrefix+"/"+k, string(v))
	return
}

func (c *Cluster) Delete(k string) (err error) {
	_, err = c.cli.Delete(c.ctx, c.kvPrefix+"/"+k)
	return
}

func (c *Cluster) SetCallbacks(callbacks cluster.Callbacks) error {
	c.callbacks = callbacks
	return c.checkConfig()
}

func (c *Cluster) Logger() logr.Logger {
	return c.log
}

func (c *Cluster) ID() string {
	return c.id
}

func (c *Cluster) checkConfig() error {
	if c.callbacks.Leader == nil {
		return errors.New("Leader callback is nil")
	}
	if c.callbacks.Follower == nil {
		return errors.New("Follower callback is nil")
	}
	return nil
}