package servlet

import (
	"fmt"

	crp "git.loafle.net/commons/rpc-go/protocol"
	crr "git.loafle.net/commons/rpc-go/registry"
	"git.loafle.net/commons/server-go"
	csw "git.loafle.net/commons/server-go/web"
	cswf "git.loafle.net/commons/server-go/web/fasthttp"
	"github.com/valyala/fasthttp"
)

type MethodMapping struct {
	Method    string
	ParamKeys []string
}

type RESTServlet struct {
	cswf.Servlets

	ServerCodec crp.ServerCodec
	RPCInvoker  crr.RPCInvoker

	MethodMapping map[string]MethodMapping
}

func (s *RESTServlet) Handle(servletCtx server.ServletCtx, ctx *fasthttp.RequestCtx) *csw.Error {
	method := string(ctx.Method())

	switch method {
	case "GET":
		return s.HandleGet(servletCtx, ctx)
	case "POST":
		return s.HandlePost(servletCtx, ctx)
	}

	return nil
}

func (s *RESTServlet) HandleGet(servletCtx server.ServletCtx, ctx *fasthttp.RequestCtx) *csw.Error {
	path := string(ctx.Path())
	if nil == s.MethodMapping {
		return csw.NewError(fasthttp.StatusNotFound, fmt.Errorf("Not Found for %s", path))
	}
	mapping, ok := s.MethodMapping[path]
	if !ok {
		return csw.NewError(fasthttp.StatusNotFound, fmt.Errorf("Not Found for %s", path))
	}

	method := mapping.Method
	params := make([]string, 0)
	if nil != mapping.ParamKeys && 0 < len(mapping.ParamKeys) {
		qargs := ctx.QueryArgs()
		if nil == qargs {
			return csw.NewError(fasthttp.StatusBadRequest, fmt.Errorf("Parameter is not valied"))
		}

		for _, k := range mapping.ParamKeys {
			buf := qargs.Peek(k)
			if nil == buf {
				return csw.NewError(fasthttp.StatusBadRequest, fmt.Errorf("Parameter for %s is not valied", k))
			}
			params = append(params, string(buf))
		}
	}

	reqCodec, err := s.ServerCodec.NewRequestWithString(method, params, nil)
	if nil != err {
		return csw.NewError(fasthttp.StatusBadRequest, err)
	}

	reply, err := s.RPCInvoker.Invoke(reqCodec, servletCtx, ctx)

	buf, err := reqCodec.NewResponse(reply, err)
	if nil != err {
		return csw.NewError(fasthttp.StatusInternalServerError, err)
	}

	ctx.SetBody(buf)

	return nil
}

func (s *RESTServlet) HandlePost(servletCtx server.ServletCtx, ctx *fasthttp.RequestCtx) *csw.Error {
	buf := ctx.PostBody()
	if nil == buf {
		return csw.NewError(fasthttp.StatusBadRequest, fmt.Errorf("Parameter is not valied"))
	}

	reqCodec, err := s.ServerCodec.NewRequest(buf)
	if nil != err {
		return csw.NewError(fasthttp.StatusBadRequest, err)
	}

	reply, err := s.RPCInvoker.Invoke(reqCodec, servletCtx, ctx)

	buf, err = reqCodec.NewResponse(reply, err)
	if nil != err {
		return csw.NewError(fasthttp.StatusInternalServerError, err)
	}

	ctx.SetBody(buf)

	return nil
}