// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
// All rights reserved.

// func-builtins.go
package expr

import (
	"math"
	"strconv"
)

func isNilFunc(ctx ExprContext, name string, args []any) (result any, err error) {
	if len(args) == 1 {
		result = args[0] == nil
	} else {
		err = errOneParam(name)
	}
	return
}

func isIntFunc(ctx ExprContext, name string, args []any) (result any, err error) {
	result = IsInteger(args[0])
	return
}

func isFloatFunc(ctx ExprContext, name string, args []any) (result any, err error) {
	result = IsFloat(args[0])
	return
}

func isBoolFunc(ctx ExprContext, name string, args []any) (result any, err error) {
	result = IsBool(args[0])
	return
}

func isStringFunc(ctx ExprContext, name string, args []any) (result any, err error) {
	result = IsString(args[0])
	return
}

func isFractionFunc(ctx ExprContext, name string, args []any) (result any, err error) {
	result = IsFract(args[0])
	return
}

func isRationalFunc(ctx ExprContext, name string, args []any) (result any, err error) {
	result = IsRational(args[0])
	return
}

func isListFunc(ctx ExprContext, name string, args []any) (result any, err error) {
	result = IsList(args[0])
	return
}

func isDictionaryFunc(ctx ExprContext, name string, args []any) (result any, err error) {
	result = IsDict(args[0])
	return
}

func intFunc(ctx ExprContext, name string, args []any) (result any, err error) {
	if len(args) == 1 {
		switch v := args[0].(type) {
		case int64:
			result = v
		case float64:
			result = int64(math.Trunc(v))
		case bool:
			if v {
				result = int64(1)
			} else {
				result = int64(0)
			}
		case string:
			var i int
			if i, err = strconv.Atoi(v); err == nil {
				result = int64(i)
			}
		default:
			err = errCantConvert(name, v, "int")
		}
	} else {
		err = errOneParam(name)
	}
	return
}

func iteratorFunc(ctx ExprContext, name string, args []any) (result any, err error) {
	return
}

func ImportBuiltinsFuncs(ctx ExprContext) {
	ctx.RegisterFunc("isNil", &simpleFunctor{f: isNilFunc}, 1, 1)
	ctx.RegisterFunc("isInt", &simpleFunctor{f: isIntFunc}, 1, 1)
	ctx.RegisterFunc("isFloat", &simpleFunctor{f: isFloatFunc}, 1, 1)
	ctx.RegisterFunc("isBool", &simpleFunctor{f: isBoolFunc}, 1, 1)
	ctx.RegisterFunc("isString", &simpleFunctor{f: isStringFunc}, 1, 1)
	ctx.RegisterFunc("isFraction", &simpleFunctor{f: isFractionFunc}, 1, 1)
	ctx.RegisterFunc("isFract", &simpleFunctor{f: isFractionFunc}, 1, 1)
	ctx.RegisterFunc("isRational", &simpleFunctor{f: isRationalFunc}, 1, 1)
	ctx.RegisterFunc("isList", &simpleFunctor{f: isListFunc}, 1, 1)
	ctx.RegisterFunc("isDictionary", &simpleFunctor{f: isDictionaryFunc}, 1, 1)
	ctx.RegisterFunc("isDict", &simpleFunctor{f: isDictionaryFunc}, 1, 1)
	ctx.RegisterFunc("int", &simpleFunctor{f: intFunc}, 1, 1)
}

func init() {
	registerImport("base", ImportBuiltinsFuncs, "Base expression tools like isNil(), int(), etc.")
}