errors.go

//go:generate protoc -I pb -I proto --go_opt=Moption.proto=.;pb,Mqbit/errors.proto=.;pb --go_out=./pb pb/option.proto proto/qbit/errors.proto

package main

import (
	"fmt"
	"regexp"
	"strconv"
	"strings"

	"google.golang.org/protobuf/compiler/protogen"
	"google.golang.org/protobuf/proto"
	"google.golang.org/protobuf/reflect/protoreflect"

	"github.com/go-qbit/protoc-gen-go-grpc-errors/pb"
)

const (
	fileDescriptorProtoPackageFieldNumber = 2
	fileDescriptorProtoSyntaxFieldNumber  = 12

	grpcPackage   = protogen.GoImportPath("google.golang.org/grpc")
	statusPackage = protogen.GoImportPath("google.golang.org/grpc/status")
)

var reSplit = regexp.MustCompile(`[\s_]+`)

func generateFile(gen *protogen.Plugin, file *protogen.File) *protogen.GeneratedFile {
	if len(file.Services) == 0 {
		return nil
	}
	filename := file.GeneratedFilenamePrefix + "_grpc_errors.pb.go"
	g := gen.NewGeneratedFile(filename, file.GoImportPath)
	// Attach all comments associated with the syntax field.
	genLeadingComments(g, file.Desc.SourceLocations().ByPath(protoreflect.SourcePath{fileDescriptorProtoSyntaxFieldNumber}))
	g.P("// Code generated by protoc-gen-go-grpc-errors. DO NOT EDIT.")
	g.P("// versions:")
	g.P("// - protoc-gen-go-grpc-errors v", version)
	g.P("// - protoc                    ", protocVersion(gen))
	if file.Proto.GetOptions().GetDeprecated() {
		g.P("// ", file.Desc.Path(), " is a deprecated file.")
	} else {
		g.P("// source: ", file.Desc.Path())
	}
	g.P()
	// Attach all comments associated with the package field.
	genLeadingComments(g, file.Desc.SourceLocations().ByPath(protoreflect.SourcePath{fileDescriptorProtoPackageFieldNumber}))
	g.P("package ", file.GoPackageName)
	g.P()
	generateFileContent(gen, file, g)
	return g
}

func generateFileContent(gen *protogen.Plugin, file *protogen.File, g *protogen.GeneratedFile) {
	if len(file.Services) == 0 {
		return
	}

	g.P("// This is a compile-time assertion to ensure that this generated file")
	g.P("// is compatible with the grpc package it is being compiled against.")
	g.P("// Requires gRPC-Go v1.32.0 or later.")
	g.P("const _ = ", grpcPackage.Ident("SupportPackageIsVersion7"))
	g.P()
	for _, service := range file.Services {
		genService(gen, file, g, service)
	}
}

func genService(gen *protogen.Plugin, file *protogen.File, g *protogen.GeneratedFile, service *protogen.Service) {
	g.P(protogen.Comments(service.GoName))
	g.P("var (")

	for _, m := range service.Methods {
		data, err := proto.Marshal(m.Desc.Options())
		if err != nil {
			gen.Error(err)
		}

		qOption := &pb.QBitMethodOptions{}
		if err := proto.Unmarshal(data, qOption); err != nil {
			gen.Error(err)
		}

		if len(qOption.Error) == 0 {
			continue
		}

		g.P("Errors", m.GoName, " = struct {")
		for _, e := range qOption.Error {
			g.P(stringToGoId(e.Message), " error")
		}
		g.P("}{")
		for _, e := range qOption.Error {
			g.P(stringToGoId(e.Message), ": ", statusPackage.Ident("Error("+strconv.FormatInt(int64(e.Code), 10)+`, "`+e.Message+`"),`))
		}
		g.P("}")
		g.P()
	}

	g.P(")")
}

func genLeadingComments(g *protogen.GeneratedFile, loc protoreflect.SourceLocation) {
	for _, s := range loc.LeadingDetachedComments {
		g.P(protogen.Comments(s))
		g.P()
	}
	if s := loc.LeadingComments; s != "" {
		g.P(protogen.Comments(s))
		g.P()
	}
}

func protocVersion(gen *protogen.Plugin) string {
	v := gen.Request.GetCompilerVersion()
	if v == nil {
		return "(unknown)"
	}
	var suffix string
	if s := v.GetSuffix(); s != "" {
		suffix = "-" + s
	}
	return fmt.Sprintf("v%d.%d.%d%s", v.GetMajor(), v.GetMinor(), v.GetPatch(), suffix)
}

func stringToGoId(s string) string {
	parts := reSplit.Split(s, -1)
	for i, s := range parts {
		parts[i] = strings.ToUpper(s[:1]) + s[1:]
	}

	return strings.Join(parts, "")
}