package redis

import (
	"fmt"
	"time"
)

type PubSub struct {
	*baseClient
}

func (c *Client) PubSub() *PubSub {
	return &PubSub{
		baseClient: &baseClient{
			opt:      c.opt,
			connPool: newSingleConnPool(c.connPool, nil, false),
		},
	}
}

func (c *Client) Publish(channel, message string) *IntReq {
	req := NewIntReq("PUBLISH", channel, message)
	c.Process(req)
	return req
}

type Message struct {
	Channel string
	Payload string
}

type PMessage struct {
	Channel string
	Pattern string
	Payload string
}

type Subscription struct {
	Kind    string
	Channel string
	Count   int
}

func (c *PubSub) Receive() (interface{}, error) {
	return c.ReceiveTimeout(0)
}

func (c *PubSub) ReceiveTimeout(timeout time.Duration) (interface{}, error) {
	cn, err := c.conn()
	if err != nil {
		return nil, err
	}
	cn.readTimeout = timeout

	replyIface, err := NewIfaceSliceReq().ParseReply(cn.Rd)
	if err != nil {
		return nil, err
	}
	reply, ok := replyIface.([]interface{})
	if !ok {
		return nil, fmt.Errorf("redis: unexpected reply type %T", replyIface)
	}

	switch msgName := reply[0].(string); msgName {
	case "subscribe", "unsubscribe", "psubscribe", "punsubscribe":
		return &Subscription{
			Kind:    msgName,
			Channel: reply[1].(string),
			Count:   int(reply[2].(int64)),
		}, nil
	case "message":
		return &Message{
			Channel: reply[1].(string),
			Payload: reply[2].(string),
		}, nil
	case "pmessage":
		return &PMessage{
			Pattern: reply[1].(string),
			Channel: reply[2].(string),
			Payload: reply[3].(string),
		}, nil
	default:
		return nil, fmt.Errorf("redis: unsupported message name: %q", msgName)
	}
}

func (c *PubSub) subscribe(cmd string, channels ...string) error {
	cn, err := c.conn()
	if err != nil {
		return err
	}

	args := append([]string{cmd}, channels...)
	req := NewIfaceSliceReq(args...)
	return c.writeReq(cn, req)
}

func (c *PubSub) Subscribe(channels ...string) error {
	return c.subscribe("SUBSCRIBE", channels...)
}

func (c *PubSub) PSubscribe(patterns ...string) error {
	return c.subscribe("PSUBSCRIBE", patterns...)
}

func (c *PubSub) unsubscribe(cmd string, channels ...string) error {
	cn, err := c.conn()
	if err != nil {
		return err
	}

	args := append([]string{cmd}, channels...)
	req := NewIfaceSliceReq(args...)
	return c.writeReq(cn, req)
}

func (c *PubSub) Unsubscribe(channels ...string) error {
	return c.unsubscribe("UNSUBSCRIBE", channels...)
}

func (c *PubSub) PUnsubscribe(patterns ...string) error {
	return c.unsubscribe("PUNSUBSCRIBE", patterns...)
}