package redis

import (
	"context"
	"crypto/tls"
	"net"
	"time"
)

// UniversalOptions information is required by UniversalClient to establish
// connections.
type UniversalOptions struct {
	// Either a single address or a seed list of host:port addresses
	// of cluster/sentinel nodes.
	Addrs []string

	// Database to be selected after connecting to the server.
	// Only single-node and failover clients.
	DB int

	// Common options.

	Dialer    func(ctx context.Context, network, addr string) (net.Conn, error)
	OnConnect func(ctx context.Context, cn *Conn) error

	Username         string
	Password         string
	SentinelPassword string

	MaxRetries      int
	MinRetryBackoff time.Duration
	MaxRetryBackoff time.Duration

	DialTimeout  time.Duration
	ReadTimeout  time.Duration
	WriteTimeout time.Duration

	PoolSize           int
	MinIdleConns       int
	MaxConnAge         time.Duration
	PoolTimeout        time.Duration
	IdleTimeout        time.Duration
	IdleCheckFrequency time.Duration

	TLSConfig *tls.Config

	// Only cluster clients.

	MaxRedirects   int
	ReadOnly       bool
	RouteByLatency bool
	RouteRandomly  bool

	// The sentinel master name.
	// Only failover clients.

	MasterName string
}

// Cluster returns cluster options created from the universal options.
func (o *UniversalOptions) Cluster() *ClusterOptions {
	if len(o.Addrs) == 0 {
		o.Addrs = []string{"127.0.0.1:6379"}
	}

	return &ClusterOptions{
		Addrs:     o.Addrs,
		Dialer:    o.Dialer,
		OnConnect: o.OnConnect,

		Username: o.Username,
		Password: o.Password,

		MaxRedirects:   o.MaxRedirects,
		ReadOnly:       o.ReadOnly,
		RouteByLatency: o.RouteByLatency,
		RouteRandomly:  o.RouteRandomly,

		MaxRetries:      o.MaxRetries,
		MinRetryBackoff: o.MinRetryBackoff,
		MaxRetryBackoff: o.MaxRetryBackoff,

		DialTimeout:        o.DialTimeout,
		ReadTimeout:        o.ReadTimeout,
		WriteTimeout:       o.WriteTimeout,
		PoolSize:           o.PoolSize,
		MinIdleConns:       o.MinIdleConns,
		MaxConnAge:         o.MaxConnAge,
		PoolTimeout:        o.PoolTimeout,
		IdleTimeout:        o.IdleTimeout,
		IdleCheckFrequency: o.IdleCheckFrequency,

		TLSConfig: o.TLSConfig,
	}
}

// Failover returns failover options created from the universal options.
func (o *UniversalOptions) Failover() *FailoverOptions {
	if len(o.Addrs) == 0 {
		o.Addrs = []string{"127.0.0.1:26379"}
	}

	return &FailoverOptions{
		SentinelAddrs: o.Addrs,
		MasterName:    o.MasterName,

		Dialer:    o.Dialer,
		OnConnect: o.OnConnect,

		DB:               o.DB,
		Username:         o.Username,
		Password:         o.Password,
		SentinelPassword: o.SentinelPassword,

		MaxRetries:      o.MaxRetries,
		MinRetryBackoff: o.MinRetryBackoff,
		MaxRetryBackoff: o.MaxRetryBackoff,

		DialTimeout:  o.DialTimeout,
		ReadTimeout:  o.ReadTimeout,
		WriteTimeout: o.WriteTimeout,

		PoolSize:           o.PoolSize,
		MinIdleConns:       o.MinIdleConns,
		MaxConnAge:         o.MaxConnAge,
		PoolTimeout:        o.PoolTimeout,
		IdleTimeout:        o.IdleTimeout,
		IdleCheckFrequency: o.IdleCheckFrequency,

		TLSConfig: o.TLSConfig,
	}
}

// Simple returns basic options created from the universal options.
func (o *UniversalOptions) Simple() *Options {
	addr := "127.0.0.1:6379"
	if len(o.Addrs) > 0 {
		addr = o.Addrs[0]
	}

	return &Options{
		Addr:      addr,
		Dialer:    o.Dialer,
		OnConnect: o.OnConnect,

		DB:       o.DB,
		Username: o.Username,
		Password: o.Password,

		MaxRetries:      o.MaxRetries,
		MinRetryBackoff: o.MinRetryBackoff,
		MaxRetryBackoff: o.MaxRetryBackoff,

		DialTimeout:  o.DialTimeout,
		ReadTimeout:  o.ReadTimeout,
		WriteTimeout: o.WriteTimeout,

		PoolSize:           o.PoolSize,
		MinIdleConns:       o.MinIdleConns,
		MaxConnAge:         o.MaxConnAge,
		PoolTimeout:        o.PoolTimeout,
		IdleTimeout:        o.IdleTimeout,
		IdleCheckFrequency: o.IdleCheckFrequency,

		TLSConfig: o.TLSConfig,
	}
}

// --------------------------------------------------------------------

// UniversalClient is an abstract client which - based on the provided options -
// represents either a ClusterClient, a FailoverClient, or a single-node Client.
// This can be useful for testing cluster-specific applications locally or having different
// clients in different environments.
type UniversalClient interface {
	Cmdable
	Context() context.Context
	AddHook(Hook)
	Watch(ctx context.Context, fn func(*Tx) error, keys ...string) error
	Do(ctx context.Context, args ...interface{}) *Cmd
	Process(ctx context.Context, cmd Cmder) error
	Subscribe(ctx context.Context, channels ...string) *PubSub
	PSubscribe(ctx context.Context, channels ...string) *PubSub
	Close() error
	PoolStats() *PoolStats
}

var (
	_ UniversalClient = (*Client)(nil)
	_ UniversalClient = (*ClusterClient)(nil)
	_ UniversalClient = (*Ring)(nil)
)

// NewUniversalClient returns a new multi client. The type of the returned client depends
// on the following conditions:
//
// 1. If the MasterName option is specified, a sentinel-backed FailoverClient is returned.
// 2. if the number of Addrs is two or more, a ClusterClient is returned.
// 3. Otherwise, a single-node Client is returned.
func NewUniversalClient(opts *UniversalOptions) UniversalClient {
	if opts.MasterName != "" {
		return NewFailoverClient(opts.Failover())
	} else if len(opts.Addrs) > 1 {
		return NewClusterClient(opts.Cluster())
	}
	return NewClient(opts.Simple())
}
