package client

import (
	"fmt"
	"github.com/apache/thrift/lib/go/thrift"
	"sync"
)

var (
	pool *Pool
)

type Pool struct {
	sync.RWMutex
	client  map[string]*Client //有几个不同的机群,它们之间没有联系
	factory map[string]thrift.TProtocolFactory
}

func newPool() *Pool {
	if pool != nil {
		return pool
	}
	pool = &Pool{
		client:  make(map[string]*Client, 0),
		factory: make(map[string]thrift.TProtocolFactory, 0),
	}
	return pool
}

func NewClient(cfg Config) (*Client, error) {
	p := newPool()
	return p.newClient(cfg)
}

func (p *Pool) newClient(cfg Config) (*Client, error) {
	p.Lock()
	defer p.Unlock()

	f, err := p.createFactory(cfg.Protocol)
	if err != nil {
		return nil, err
	}

	return p.createClient(f, cfg.Target)
}

func (p *Pool) createFactory(protocol string) (thrift.TProtocolFactory, error) {

	if f, ok := p.factory[protocol]; ok {
		return f, nil
	}

	f, err := newFactory(protocol)
	if err != nil {
		return nil, err
	}
	p.factory[protocol] = f
	return f, nil
}

func (p *Pool) createClient(tpf thrift.TProtocolFactory, target string) (*Client, error) {

	if cli, ok := p.client[target]; ok {
		return cli, nil
	}
	cli, err := newClient(tpf, target)
	if err != nil {
		return nil, err
	}

	p.client[target] = cli

	return cli, nil
}

func newFactory(protocol string) (thrift.TProtocolFactory, error) {

	var factory thrift.TProtocolFactory
	var err error

	switch protocol {
	case "compact":
		factory = thrift.NewTCompactProtocolFactoryConf(&thrift.TConfiguration{})
		break
	case "simple_json":
		factory = thrift.NewTCompactProtocolFactoryConf(&thrift.TConfiguration{})
		break
	case "json":
		factory = thrift.NewTJSONProtocolFactory()
		break
	case "binary", "":
		factory = thrift.NewTBinaryProtocolFactoryConf(&thrift.TConfiguration{})
		break
	default:
		err = fmt.Errorf("NOT support %v protocol factory", protocol)
	}
	return factory, err
}