package schema

import (
	"errors"
	"reflect"
	"strconv"

	"github.com/google/generative-ai-go/genai"
	"github.com/openai/openai-go"
)

// just enforcing that basic implements Type
var _ Type = basic{}

type DataType string

const (
	TypeString  DataType = "string"
	TypeInteger DataType = "integer"
	TypeNumber  DataType = "number"
	TypeBoolean DataType = "boolean"
	TypeObject  DataType = "object"
	TypeArray   DataType = "array"
)

type basic struct {
	DataType
	typeName string

	// index is the position of the parameter in the StructField of the function's parameter struct
	index int

	// required is a flag that indicates whether the parameter is required in the function's parameter struct.
	// this is inferred by if the parameter is a pointer type or not.
	required bool

	// description is a llm-readable description of the parameter passed to openai
	description string
}

func (b basic) OpenAIParameters() openai.FunctionParameters {
	return openai.FunctionParameters{
		"type":        b.typeName,
		"description": b.description,
	}
}

func (b basic) GoogleParameters() *genai.Schema {
	var t = genai.TypeUnspecified

	switch b.DataType {
	case TypeString:
		t = genai.TypeString
	case TypeInteger:
		t = genai.TypeInteger
	case TypeNumber:
		t = genai.TypeNumber
	case TypeBoolean:
		t = genai.TypeBoolean
	case TypeObject:
		t = genai.TypeObject
	case TypeArray:
		t = genai.TypeArray
	default:
		t = genai.TypeUnspecified
	}
	return &genai.Schema{
		Type:        t,
		Description: b.description,
	}
}

func (b basic) Required() bool {
	return b.required
}

func (b basic) Description() string {
	return b.description
}

func (b basic) FromAny(val any) (reflect.Value, error) {
	v := reflect.ValueOf(val)

	switch b.DataType {
	case TypeString:
		var val = v.String()

		return reflect.ValueOf(val), nil

	case TypeInteger:
		if v.Kind() == reflect.Float64 {
			return v.Convert(reflect.TypeOf(int(0))), nil
		} else if v.Kind() != reflect.Int {
			return reflect.Value{}, errors.New("expected int, got " + v.Kind().String())
		} else {
			return v, nil
		}

	case TypeNumber:
		if v.Kind() == reflect.Float64 {
			return v.Convert(reflect.TypeOf(float64(0))), nil
		} else if v.Kind() != reflect.Float64 {
			return reflect.Value{}, errors.New("expected float64, got " + v.Kind().String())
		} else {
			return v, nil
		}

	case TypeBoolean:
		if v.Kind() == reflect.Bool {
			return v, nil
		} else if v.Kind() == reflect.String {
			b, err := strconv.ParseBool(v.String())
			if err != nil {
				return reflect.Value{}, errors.New("expected bool, got " + v.Kind().String())
			}
			return reflect.ValueOf(b), nil
		} else {
			return reflect.Value{}, errors.New("expected bool, got " + v.Kind().String())
		}

	default:
		return reflect.Value{}, errors.New("unknown type")
	}
}

func (b basic) SetValueOnField(obj reflect.Value, val reflect.Value) {
	// if this basic type is not required that means it's a pointer type
	// so we need to create a new value of the type of the pointer
	if !b.required {
		vv := reflect.New(obj.Field(b.index).Type().Elem())

		// and then set the value of the pointer to the new value
		vv.Elem().Set(val)

		obj.Field(b.index).Set(vv)
		return
	}
	obj.Field(b.index).Set(val)
}