package request

import (
	"go/ast"
	"go/parser"
	"go/token"
	"reflect"
	"strconv"
	"strings"
	"testing"
	"unicode"
)

func TestRequestStructTagsUseSnakeCase(t *testing.T) {
	fset := token.NewFileSet()
	packages, err := parser.ParseDir(fset, ".", nil, 0)
	if err != nil {
		t.Fatalf("parse request package: %v", err)
	}

	for _, pkg := range packages {
		for filename, file := range pkg.Files {
			ast.Inspect(file, func(node ast.Node) bool {
				field, ok := node.(*ast.Field)
				if !ok || field.Tag == nil {
					return true
				}
				rawTag, err := strconv.Unquote(field.Tag.Value)
				if err != nil {
					t.Errorf("%s: invalid struct tag %s: %v", filename, field.Tag.Value, err)
					return true
				}
				for _, key := range []string{"json", "form", "query", "uri"} {
					name := strings.Split(reflect.StructTag(rawTag).Get(key), ",")[0]
					if name == "" || name == "-" {
						continue
					}
					if !isSnakeCaseRequestName(name) {
						t.Errorf("%s: %s tag %q must use snake_case", filename, key, name)
					}
				}
				return true
			})
		}
	}
}

func isSnakeCaseRequestName(name string) bool {
	for _, r := range name {
		if unicode.IsLower(r) || unicode.IsDigit(r) || r == '_' {
			continue
		}
		return false
	}
	return true
}