package redisx

import (
	"context"
	"time"

	"github.com/redis/go-redis/v9"
	"github.com/zeromicro/go-zero/core/stores/cache"
)

type MasterSlaveCluster struct {
	Client     *redis.ClusterClient
	MasterHost string
	SlaveHost  string
	HasSlave   bool
}

func NewMasterSlaveCluster(cacheConf cache.CacheConf) *MasterSlaveCluster {
	cacheConf = filterCacheConf(cacheConf)
	if len(cacheConf) == 0 {
		return &MasterSlaveCluster{}
	}

	master := cacheConf[0]
	slave := cacheConf[0]
	hasSlave := len(cacheConf) > 1
	if hasSlave {
		slave = cacheConf[1]
	}

	client := redis.NewClusterClient(&redis.ClusterOptions{
		Addrs:    []string{master.Host},
		Username: master.User,
		Password: master.Pass,
		ReadOnly: hasSlave,
		ClusterSlots: func(ctx context.Context) ([]redis.ClusterSlot, error) {
			nodes := []redis.ClusterNode{{Addr: master.Host}}
			if hasSlave {
				nodes = append(nodes, redis.ClusterNode{Addr: slave.Host})
			}

			return []redis.ClusterSlot{{
				Start: 0,
				End:   16383,
				Nodes: nodes,
			}}, nil
		},
	})

	return &MasterSlaveCluster{
		Client:     client,
		MasterHost: master.Host,
		SlaveHost:  slave.Host,
		HasSlave:   hasSlave,
	}
}

func ConnectMasterSlaveCluster(cacheConf cache.CacheConf, timeout time.Duration) (*MasterSlaveCluster, error) {
	cluster := NewMasterSlaveCluster(cacheConf)
	if cluster == nil || cluster.Client == nil {
		return cluster, nil
	}

	ctx, cancel := context.WithTimeout(context.Background(), timeout)
	defer cancel()

	if err := cluster.Ping(ctx); err != nil {
		return cluster, err
	}

	return cluster, nil
}

func (m *MasterSlaveCluster) Ping(ctx context.Context) error {
	if m == nil || m.Client == nil {
		return nil
	}

	return m.Client.Ping(ctx).Err()
}

func filterCacheConf(cacheConf cache.CacheConf) cache.CacheConf {
	if len(cacheConf) == 0 {
		return cacheConf
	}

	filtered := make(cache.CacheConf, 0, len(cacheConf))
	for _, node := range cacheConf {
		if node.Host == "" {
			continue
		}
		filtered = append(filtered, node)
	}

	return filtered
}