package main

import (
	"bytes"
	"fmt"
	"os"
	"path/filepath"
	"text/template"
	"time"

	"google.golang.org/protobuf/compiler/protogen"
)

func (c *Coco) generateErrorCode(plugin *protogen.Plugin) {
	for _, pbFile := range plugin.Files {
		for _, e := range pbFile.Enums {
			if e.Desc.Name() != "ErrCode" {
				continue
			}
			values, err := c.errcodeDefine(string(pbFile.GoPackageName), e)
			if err != nil {
				_, _ = fmt.Fprintf(os.Stderr, "generate error code failed: %v", err)
				continue
			}
			filename := fmt.Sprintf("%s/autogen_errcode_%s.go",
				filepath.Dir(pbFile.GeneratedFilenamePrefix), pbFile.GoPackageName)
			g := plugin.NewGeneratedFile(filename, pbFile.GoImportPath)
			g.P("// Code generated by protoc-gen-coco. DO NOT EDIT.")
			g.P("// source: ", pbFile.GeneratedFilenamePrefix, ".proto")
			g.P("// generate at: ", time.Now().Format(time.DateTime))
			g.P()
			g.P("package ", pbFile.GoPackageName)
			g.P()
			g.P(`import (
	"gitter.top/coco/coco/core"
)`)
			g.P()
			g.P(values)
			g.P()
		}
	}
}

func (c *Coco) errcodeDefine(pkgName string, enum *protogen.Enum) (string, error) {
	tpl, err := template.New("errcode_map").Parse(generateErrorCode)
	if err != nil {
		return "", fmt.Errorf("parse error code template failed: %v", err)
	}

	type T struct {
		ErrorCode   int32
		ErrorMsg    string
		ErrorDefine string
	}
	var ts []T
	for _, enumItem := range enum.Values {
		ts = append(ts, T{
			ErrorCode:   int32(enumItem.Desc.Number()),
			ErrorMsg:    getCommentFromEnumItem(enumItem.Comments),
			ErrorDefine: string(enumItem.Desc.Name()),
		})
	}
	type TT struct {
		PkgName    string
		ErrorCodes []T
	}

	var tt = TT{PkgName: JavascriptCaseToCamelCase(pkgName), ErrorCodes: ts}
	tpl.DefinedTemplates()
	var buf bytes.Buffer
	if err = tpl.Execute(&buf, tt); err != nil {
		return "", fmt.Errorf("execute error code template failed: %v", err)
	}
	return buf.String(), nil
}

const generateErrorCode = `var (
	{{.PkgName}}ErrcodeMap = map[int32]string{ {{range $errcode := .ErrorCodes}}
		int32(ErrCode_{{$errcode.ErrorDefine}}):	"{{$errcode.ErrorMsg}}",{{end}}
	}
)

var (
	{{range $errcode := .ErrorCodes}}{{$errcode.ErrorDefine}} = &core.ErrMsg{ErrCode: {{$errcode.ErrorCode}}, ErrMsg: "{{$errcode.ErrorMsg}}"}
{{end}}
)
`