package builtin

import (
	"strings"

	"gitee.com/blizzard1413/dsl/function"
	"gitee.com/blizzard1413/dsl/types"
)

// RegisterString 注册所有字符串函数
func RegisterString(registry function.Registry) error {
	stringFuncs := []struct {
		name string
		fn   func([]interface{}) (interface{}, error)
		sig  *function.Signature
	}{
		{"String.concat", stringConcat, function.NewVariadicSignature(0, types.NewStringType())},
		{"String.length", stringLength, function.NewSignature([]types.Type{types.NewStringType()}, types.NewNumberType())},
		{"String.toUpperCase", stringToUpperCase, function.NewSignature([]types.Type{types.NewStringType()}, types.NewStringType())},
		{"String.toLowerCase", stringToLowerCase, function.NewSignature([]types.Type{types.NewStringType()}, types.NewStringType())},
		{"String.trim", stringTrim, function.NewSignature([]types.Type{types.NewStringType()}, types.NewStringType())},
		{"String.split", stringSplit, function.NewSignature([]types.Type{types.NewStringType(), types.NewStringType()}, types.NewArrayType(types.NewStringType()))},
	}

	for _, sf := range stringFuncs {
		if err := registry.RegisterNative(sf.name, sf.sig, sf.fn); err != nil {
			return err
		}
	}

	return nil
}

// stringConcat 连接字符串
func stringConcat(args []interface{}) (interface{}, error) {
	var sb strings.Builder
	for _, arg := range args {
		sb.WriteString(toString(arg))
	}
	return sb.String(), nil
}

// stringLength 返回字符串长度
func stringLength(args []interface{}) (interface{}, error) {
	s := toString(args[0])
	return float64(len(s)), nil
}

// stringToUpperCase 转换为大写
func stringToUpperCase(args []interface{}) (interface{}, error) {
	s := toString(args[0])
	return strings.ToUpper(s), nil
}

// stringToLowerCase 转换为小写
func stringToLowerCase(args []interface{}) (interface{}, error) {
	s := toString(args[0])
	return strings.ToLower(s), nil
}

// stringTrim 去除首尾空白
func stringTrim(args []interface{}) (interface{}, error) {
	s := toString(args[0])
	return strings.TrimSpace(s), nil
}

// stringSplit 分割字符串
func stringSplit(args []interface{}) (interface{}, error) {
	s := toString(args[0])
	separator := toString(args[1])

	parts := strings.Split(s, separator)

	// 转换为 []interface{}
	result := make([]interface{}, len(parts))
	for i, part := range parts {
		result[i] = part
	}

	return result, nil
}