package main

import (
	"fmt"
	"strings"
	"time"

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

const (
	errorsPackage       = protogen.GoImportPath("gitee.com/dhcy/go-protobuf/errors")
	enumNameRequired    = "REASON" // 枚举命名需要带有字段
	enumValueMinxLength = 4
	enumModuleNumKey    = "+module="
	dateFormat          = "2006-01-02 15:04:05"
)

// generateFile generates a _errors.pb.go file containing go-protobuf errors definitions.
func generateFile(gen *protogen.Plugin, file *protogen.File) *protogen.GeneratedFile {
	if len(file.Enums) == 0 {
		return nil
	}
	filename := file.GeneratedFilenamePrefix + "_errors.pb.go"
	g := gen.NewGeneratedFile(filename, file.GoImportPath)
	g.P("// Code generated by protoc-gen-go-errors. DO NOT EDIT.")
	g.P(strings.Join([]string{"// protoc-gen-go-errors:", release}, " "))
	g.P(strings.Join([]string{"// build-date:", time.Now().Format(dateFormat)}, " "))
	g.P()
	g.P("package ", file.GoPackageName)
	g.P()
	generateFileContent(gen, file, g)
	return g
}

// generateFileContent generates the go-protobuf errors definitions, excluding the package statement.
func generateFileContent(gen *protogen.Plugin, file *protogen.File, g *protogen.GeneratedFile) {
	if len(file.Enums) == 0 {
		return
	}

	g.P("// This is a compile-time assertion to ensure that this generated file")
	g.P("// is compatible with the go-protobuf package it is being compiled against.")
	g.P("const _ = ", errorsPackage.Ident("SupportPackageIsVersion1"))
	g.P()
	index := 0
	for _, enum := range file.Enums {
		skip := genErrorsReason(gen, file, g, enum)
		if !skip {
			index++
		}
	}
	// If all enums do not contain 'errors.code', the current file is skipped
	if index == 0 {
		g.Skip()
	}
}

func genErrorsReason(gen *protogen.Plugin, file *protogen.File,
	g *protogen.GeneratedFile, enum *protogen.Enum) bool {

	// 匹配符合规则的枚举
	name := string(enum.Desc.Name())
	nameUpper := strings.ToUpper(name)
	if !strings.Contains(nameUpper, enumNameRequired) {
		return true
	}
	nameModule := strings.Replace(nameUpper, enumNameRequired, "", -1)
	moduleNum := getNotModuleNum(enum)
	// 对module进行表
	var ew errorWrapper
	for _, v := range enum.Values {
		// 枚举值 如:INFO_SYSTEM_CACHE_TIMEOUT
		enumValue := string(v.Desc.Name())
		values := strings.Split(enumValue, "_")
		if len(values) < enumValueMinxLength {
			continue
		}
		// module
		module := strings.ToUpper(values[2])
		// 检查当前枚举中module命名
		if module != nameModule {
			panic(fmt.Sprintf("enmu %s name not equal to the module name %s err %s != %s",
				enum.Desc.Name(), enumValue, nameModule, module))
		}
		// 获取注释message
		message := string(v.Comments.Leading)
		if len(message) == 0 {
			panic(fmt.Errorf("enmu %s no valid comment %s, please check", enum.Desc.Name(), enumValue))
		}
		message = strings.Replace(message, "//", "", -1)
		message = strings.Replace(message, "\n", "", -1)
		message = strings.Replace(message, " ", "", -1)
		// typ
		typ := strings.ToUpper(values[0])
		// source
		source := strings.ToUpper(values[1])
		// code
		code := buildErrorCode(typ, source, moduleNum, int32(v.Desc.Number()))

		err := &errorInfo{
			Name:       string(enum.Desc.Name()),
			Value:      enumValue,
			Code:       code,
			Message:    message,
			CamelValue: case2Camel(enumValue),
		}
		ew.Errors = append(ew.Errors, err)
	}
	if len(ew.Errors) == 0 {
		return true
	}
	g.P(ew.execute())
	return false
}

func case2Camel(name string) string {
	if !strings.Contains(name, "_") {
		upperName := strings.ToUpper(name)
		if upperName == name {
			name = strings.ToLower(name)
		}
		return strings.Title(name)
	}
	name = strings.ToLower(name)
	name = strings.Replace(name, "_", " ", -1)
	name = strings.Title(name)
	return strings.Replace(name, " ", "", -1)
}

// getNotModuleNum 获取注释中的模块号(如果没有会panic)
func getNotModuleNum(enum *protogen.Enum) string {
	// 获取注释中的模块号
	nots := strings.Split(string(enum.Comments.Leading), "\n")
	for i := 0; i < len(nots); i++ {
		// 匹配是否包含模块key
		if strings.Contains(nots[i], enumModuleNumKey) {
			moduleNum := strings.Replace(nots[i], enumModuleNumKey, "", -1)
			return strings.Replace(moduleNum, " ", "", -1)
		}
	}
	panic(fmt.Sprintf("enmu %s no %s data, please check", enum.Desc.Name(), enumModuleNumKey))
}

// buildErrorCode 组装error code
func buildErrorCode(typ, source, module string, enumNum int32) string {
	return fmt.Sprintf("%s%s%s%05d", string(typ[0]), string(source[0]), module, enumNum)
}