package grpcall

import (
	"context"
	"fmt"

	"github.com/jhump/protoreflect/desc"
	"google.golang.org/grpc/metadata"
)

type Response struct {
	method *desc.MethodDescriptor
	header *metadata.MD
	data   string
	send   chan string
	recv   chan string
	done   chan error
	cancel context.CancelFunc
}

func (this Response) Header() metadata.MD {
	return *this.header
}

func (this Response) Data() (string, error) {
	if this.method.IsClientStreaming() || this.method.IsServerStreaming() {
		return "", fmt.Errorf("%q is %s, cannot use unary data", this.method.GetFullyQualifiedName(), this.GetCategory())
	}
	return this.data, nil
}

// 发送数据流
func (this Response) Send() (chan<- string, error) {
	if !this.method.IsClientStreaming() || !this.method.IsServerStreaming() {
		return nil, fmt.Errorf("%q is %s, cannot use send streaming func", this.method.GetFullyQualifiedName(), this.GetCategory())
	}
	return this.send, nil
}

// 接收数据流
func (this Response) Recv() (<-chan string, error) {
	if !this.method.IsServerStreaming() {
		return nil, fmt.Errorf("%q is %s, cannot use streaming func", this.method.GetFullyQualifiedName(), this.GetCategory())
	}
	return this.recv, nil
}

// 数据是否响应结束
func (this Response) Done() (<-chan error, error) {
	if !this.method.IsServerStreaming() {
		return nil, fmt.Errorf("%q is %s, cannot use streaming func", this.method.GetFullyQualifiedName(), this.GetCategory())
	}
	return this.done, nil
}

// 取消接收数据
func (this Response) Cancel() {
	if this.method.IsServerStreaming() {
		this.cancel()
	}
}

func (this Response) GetCategory() string {
	if this.method.IsClientStreaming() && this.method.IsServerStreaming() {
		return "bidi-streaming"
	} else if this.method.IsClientStreaming() {
		return "client-streaming"
	} else if this.method.IsServerStreaming() {
		return "server-streaming"
	} else {
		return "unary"
	}
}