package astfoo

import (
	"bytes"
	"fmt"
	"go/ast"
	"go/format"
	"go/parser"
	"go/token"
	"os"
)

func FormatFoo(parseFilePath, outputFunction string) {
	fileContent := `
package algorithmfoo

import (
	"strings"
)

// ConvertCamelCase2SnakeCaseWithPhrase 将驼峰命名法转换为蛇形命名法：XxxYyyZzz -> xxx_yyy_zzz
// Abc 开头 | 中间 DONE
// ABC 开头 | 中间
func ConvertCamelCase2SnakeCaseWithPhrase(camelCase string, phraseMap map[string]struct{}) string {
	builder := strings.Builder{}
	// ...
	return builder.String()
}

`

	fileAST, err := parser.ParseFile(token.NewFileSet(), "", fileContent, parser.ParseComments)
	if err != nil {
		panic(err)
	}

	outputFile, err := os.OpenFile(fmt.Sprintf("%v.bak", parseFilePath), os.O_CREATE|os.O_TRUNC|os.O_RDWR, 0644)
	if err != nil {
		panic(err)
	}
	defer outputFile.Close()

	buffer := &bytes.Buffer{}
	if fileAST.Scope != nil {
		for name, object := range fileAST.Scope.Objects {
			if object.Kind == ast.Fun && name == outputFunction {
				decl := object.Decl.(*ast.FuncDecl)
				if declLen := decl.End() - decl.Pos(); buffer.Cap() < int(declLen) {
					buffer.Grow(int(declLen))
				}
				err = format.Node(buffer, token.NewFileSet(), decl)
				if err != nil {
					panic(err)
				}
				outputFile.Write(buffer.Bytes())
				buffer.Reset()
				break
			}
		}
	}
}

package astfoo

import (
	"io/fs"
	"reflect"
	"testing"
)

func TestFormatFoo(t *testing.T) {
	type args struct {
		parseFilePath  string
		outputFunction string
	}
	tests := []struct {
		name string
		args args
	}{
		// TODO: Add test cases.
		{
			"test case 1",
			args{
				parseFilePath:  ".\\tmp.go",
				outputFunction: "ConvertCamelCase2SnakeCaseWithPhrase",
			},
		},
	}
	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			FormatFoo(tt.args.parseFilePath, tt.args.outputFunction)
		})
	}
}

// ConvertCamelCase2SnakeCaseWithPhrase 将驼峰命名法转换为蛇形命名法：XxxYyyZzz -> xxx_yyy_zzz
// Abc 开头 | 中间 DONE
// ABC 开头 | 中间
func ConvertCamelCase2SnakeCaseWithPhrase(camelCase string, phraseMap map[string]struct{}) string {
	builder := strings.Builder{}
	return builder.String()
}

func ConvertCamelCase2SnakeCaseWithPhrase(camelCase string, phraseMap map // ConvertCamelCase2SnakeCaseWithPhrase 将驼峰命名法转换为蛇形命名法：XxxYyyZzz -> xxx_yyy_zzz
// Abc 开头 | 中间 DONE
// ABC 开头 | 中间
[string]struct{}) string {
	builder := strings.Builder{}
	return builder.String()
}