package encode // import "udico.de/uditaren/opier/encode"
import (
	"bytes"
	"fmt"
	"sort"
	"strconv"
	"strings"
	"udico.de/opier/openapi"
)

type simpleparam struct {
	Name string
	Type string
	In   string
}

// implement sort interface on simpleparam
type simpleparamslice []*simpleparam

func (s simpleparamslice) Len() int      { return len(s) }
func (s simpleparamslice) Swap(i, j int) { s[i], s[j] = s[j], s[i] }
func (s simpleparamslice) Less(i, j int) bool {
	val := func(s string) int {
		switch s {
		case "path":
			return 0
		case "header":
			return 1
		case "query":
			return 2
		}
		return 99
	}
	iVal := val(s[i].In)
	jVal := val(s[j].In)
	iStr := s[i].Name
	jStr := s[j].Name
	if iVal == jVal {
		return strings.Compare(iStr, jStr) < 0
	}
	return iVal < jVal
}

// Funcs generates all functions for a given tag
//
// tag is a
//     tag name
func (e Encoder) Funcs(tag string, operations []*openapi.Operation) string {

	tBuf := bytes.Buffer{}
	tBuf.WriteString(fmt.Sprintf("package %v\n\n", e.Package))
	tBuf.WriteString(e.GeneratedHeader())
	tBuf.WriteString(e.tagType(tag))

	tFuncPrefix := "p" + NormalizeName(tag)

	for _, op := range operations {
		// name -> type
		tParams := make([]*simpleparam, 0, 5)

		if op.Description != "" {
			tDesc := strings.Split(strings.TrimSpace(op.Description), "\n")
			for _, tLine := range tDesc {
				tBuf.WriteString(fmt.Sprintf("// %v\n", tLine))
			}
		}
		for _, params := range op.Path().Parameters {
			tBuf.WriteString("// param [PATH] ")
			if params.Ref != "" {
				// ref param
				tRefParam := e.api.ResolveParameter(params.Ref)
				tBuf.WriteString(fmt.Sprintf("REF: %v\n", params.Ref))
				tBuf.WriteString(Comment(tRefParam.Name, 2))
				tParams = append(tParams, &simpleparam{
					Name: tRefParam.Name,
					Type: tRefParam.Schema.GoType(),
					In:   "path",
				})
			} else {
				tBuf.WriteString(fmt.Sprintf("TYPE: %v\n", params.Schema.Type))
				tParams = append(tParams, &simpleparam{
					Name: params.Name,
					Type: params.Schema.GoType(),
					In:   "path",
				})
			}
		}
		for _, params := range op.Parameters {
			//tBuf.WriteString("// param ")
			tBuf.WriteString(Comment(fmt.Sprintf("param [%v] %v: %v\n", params.In, params.Name, params.Description), 0))
			tParams = append(tParams, &simpleparam{
				Name: params.Name,
				Type: params.Schema.GoType(),
				In:   string(params.In),
			})
		}
		if op.RequestBody != nil {
			tBuf.WriteString(fmt.Sprintf("// body: %v\n", op.RequestBody.Description))
			for k, v := range op.RequestBody.Content {
				tBuf.WriteString(fmt.Sprintf("//   [%v]: %v\n", k, v.Schema.Ref))
			}
		}

		var tResponseType *openapi.ResponseObject = nil
		for tCode, tResponse := range op.Responses {
			tBuf.WriteString(Comment(fmt.Sprintf("response [%v]: %v\n", tCode, tResponse.Description), 0))
			tCodeVal, _ := strconv.Atoi(tCode)
			if tCodeVal/100 == 2 {
				tResponseType = tResponse
			}
		}
		tResponses := make([]*simpleparam, 0, 2)
		if tResponseType != nil {
			for k, v := range tResponseType.Headers {
				// each given responseheader is a return parameter
				tResponses = append(tResponses, &simpleparam{
					Name: k,
					Type: v.Schema.TypeOrReference(),
					In:   "header",
				})
			}
			if len(tResponseType.Content) > 0 {
				tSchema := tResponseType.Content["application/json"].Schema
				tResponses = append(tResponses, &simpleparam{
					Name: "ret",
					Type: tSchema.GoType(),
					In:   "body",
				})
			}
		}

		sort.Sort(simpleparamslice(tParams))
		sort.Sort(simpleparamslice(tResponses))

		// parameter list:
		tResponses = append(tResponses, &simpleparam{
			Name: "err",
			Type: "error",
		})
		tParamBuf := &strings.Builder{}
		for i, tParam := range tParams {
			if i > 0 {
				tParamBuf.WriteString(", ")
			}
			tParamBuf.WriteString(NormalizeName(tParam.Name))
			tParamBuf.WriteString(" " + tParam.Type)
		}

		// body parameter:
		if op.RequestBody != nil {
			ref := op.RequestBody.Content["application/json"].Schema.Ref
			if ref != "" {
				if tParamBuf.Len() > 0 {
					tParamBuf.WriteString(", ")
				}
				tParamBuf.WriteString(fmt.Sprintf("data *%v", e.api.ResolveSchema(ref).Name()))
			} else {
				tParamBuf.WriteString(" /* IMPLEMENT BODY SCHEMA which is not $ref */")
			}
		}
		tParamStr := tParamBuf.String()

		tResponseBuf := &strings.Builder{}
		tResponseBuf.WriteString("(")
		for i, tResponse := range tResponses {
			if i > 0 {
				tResponseBuf.WriteString(", ")
			}
			tResponseBuf.WriteString(tResponse.Name + " ")
			tResponseBuf.WriteString(tResponse.Type)
		}
		tResponseBuf.WriteString(")")
		tResponseStr := tResponseBuf.String()

		tBuf.WriteString(fmt.Sprintf("func (p %v) %v(%v) %v {\n", tFuncPrefix, NormalizeName(op.OperationId), tParamStr, tResponseStr))

		tBuf.WriteString(fmt.Sprintf("  // [%v]%v operation here \n", op.Method(), op.Path().Name))
		// assemble request
		// insert path parameters
		tBuf.WriteString(fmt.Sprintf("  tPath := p.base+\"%v\"\n", op.Path().Name))
		for _, p := range tParams {
			if p.In == "path" {
				tBuf.WriteString(fmt.Sprintf("  replacePathParam(&tPath, \"%v\", %v)\n", p.Name, NormalizeName(p.Name)))
			}
		}

		// post/put params ("body")
		tBufBody := "nil"
		if op.RequestBody != nil {
			tBuf.WriteString("  var tData []byte = nil\n")
			tBuf.WriteString("  tData, err = json.Marshal(data)\n")
			tBuf.WriteString("  if err != nil {\n")
			tBuf.WriteString("    return\n")
			tBuf.WriteString("  }\n")
			tBuf.WriteString("  tBuf := bytes.NewBuffer(tData)\n")
			tBufBody = "tBuf"
		}

		tBuf.WriteString(fmt.Sprintf("  req, _ := http.NewRequest(\"%v\", tPath, %v)\n", op.Method(), tBufBody))
		// add header parameters
		for _, p := range tParams {
			if p.In == "header" {
				tBuf.WriteString(fmt.Sprintf("  req.Header.Add(\"%v\", \"%v\")\n", p.Name, NormalizeName(p.Name)))
			}
		}

		// add query parameters
		tQBuf := &strings.Builder{}
		tQBufHasData := false
		tQBuf.WriteString("  q := req.URL.Query()\n")
		for _, p := range tParams {
			if p.In == "query" {
				tQBuf.WriteString(fmt.Sprintf("  addQueryParameter(&q, \"%v\", joinIfArray(%v))\n", p.Name, NormalizeName(p.Name)))
				tQBufHasData = true
			}
		}
		tQBuf.WriteString("  req.URL.RawQuery = q.Encode()\n\n")
		if tQBufHasData {
			tBuf.WriteString(tQBuf.String())
		}

		tBuf.WriteString("  resp, err := p.client.Do(req)\n")
		tBuf.WriteString("  if err != nil {\n    return\n  }\n")
		tBuf.WriteString("  defer resp.Body.Close()\n")
		tBuf.WriteString("  if resp.StatusCode / 100 != 2 {\n    err = errors.New(resp.Status)\n    return\n  }\n")
		// parse response
		for _, r := range tResponses {
			if r.In == "header" {
				tBuf.WriteString(fmt.Sprintf("  %v = resp.Header.Get(\"%v\")\n", NormalizeName(r.Name), r.Name))
			}
		}
		for _, r := range tResponses {
			if r.In == "body" {
				tType := r.Type
				if strings.HasPrefix(tType, "*") {
					tType = "&" + strings.TrimPrefix(tType, "*")
				}
				tBuf.WriteString("  tResponseData, err := ioutil.ReadAll(resp.Body)\n")
				tBuf.WriteString("  if err != nil {\n")
				tBuf.WriteString("    return\n")
				tBuf.WriteString("  }\n")
				tBuf.WriteString(fmt.Sprintf("  ret = %v{}\n", tType))
				tBuf.WriteString("  err = json.Unmarshal(tResponseData, ret)\n")
				break // there can be only one
			}
		}

		tBuf.WriteString(fmt.Sprintf("  return\n}\n\n"))
	}



	return tBuf.String()
}

func (e Encoder) tagType(tag string) string {
	tNorm := NormalizeName(tag)
	tBuf := bytes.Buffer{}
	tBuf.WriteString("import (\n  \"bytes\"\n  \"encoding/json\"\n  \"errors\"\n  \"io/ioutil\"\n  \"net/http\"\n)\n")
	tBuf.WriteString(Comment(e.getTagDescription(tag), 0))
	tBuf.WriteString(fmt.Sprintf("type p%v struct {\n", tNorm))
	tBuf.WriteString("  client *http.Client\n")
	tBuf.WriteString("  base   string\n")
	tBuf.WriteString("}\n\n")
	tBuf.WriteString(fmt.Sprintf("func %v(aClient *http.Client, aBase string) p%v {\n", NormalizeName("new-"+tag), tNorm))
	tBuf.WriteString(fmt.Sprintf("  return p%v{\n", tNorm))
	tBuf.WriteString("    client: aClient,\n")
	tBuf.WriteString("    base:   aBase,\n")
	tBuf.WriteString("  }\n")
	tBuf.WriteString("}\n\n")
	return tBuf.String()
}

func (e Encoder) getTagDescription(tag string) string {
	for _, v := range e.api.Tags {
		if v.Name == tag {
			return v.Description
		}
	}
	return ""
}