package schema

import (
	"reflect"
	"strings"

	"github.com/sashabaranov/go-openai/jsonschema"
)

// GetType will, given an interface{} that is a struct (NOT a pointer to a struct), return the Type of the struct that
// can be used to generate a json schema and build an object from a parsed json object.
func GetType(a any) Type {
	t := reflect.TypeOf(a)

	if t.Kind() != reflect.Struct {
		panic("GetType expects a struct")
	}

	return getObject(t)
}

func getFromType(t reflect.Type, b basic) Type {
	if t.Kind() == reflect.Ptr {
		t = t.Elem()
		b.required = false
	}

	switch t.Kind() {
	case reflect.String:
		b.DataType = jsonschema.String
		return b

	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
		b.DataType = jsonschema.Integer
		return b

	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
		b.DataType = jsonschema.Integer
		return b

	case reflect.Float32, reflect.Float64:
		b.DataType = jsonschema.Number
		return b

	case reflect.Bool:
		b.DataType = jsonschema.Boolean
		return b

	case reflect.Struct:
		o := getObject(t)

		o.basic.required = b.required
		o.basic.index = b.index
		o.basic.description = b.description

		return o

	case reflect.Slice:
		return getArray(t)

	default:
		panic("unhandled default case for " + t.Kind().String() + " in getFromType")
	}
}

func getField(f reflect.StructField, index int) Type {
	b := basic{
		index:       index,
		required:    true,
		description: "",
	}

	t := f.Type

	// if the tag "description" is set, use that as the description
	if desc, ok := f.Tag.Lookup("description"); ok {
		b.description = desc
	}

	// now if the tag "enum" is set, we need to create an enum type
	if v, ok := f.Tag.Lookup("enum"); ok {
		vals := strings.Split(v, ",")

		for i := 0; i < len(vals); i++ {
			vals[i] = strings.TrimSpace(vals[i])

			if vals[i] == "" {
				vals = append(vals[:i], vals[i+1:]...)
			}
		}

		return enum{
			basic:  b,
			values: vals,
		}

	}

	return getFromType(t, b)
}

func getObject(t reflect.Type) object {
	fields := make(map[string]Type, t.NumField())
	for i := 0; i < t.NumField(); i++ {
		field := t.Field(i)
		fields[field.Name] = getField(field, i)
	}

	return object{
		basic:  basic{DataType: jsonschema.Object},
		fields: fields,
	}
}

func getArray(t reflect.Type) array {
	res := array{
		basic: basic{
			DataType: jsonschema.Array,
		},
	}

	res.items = getFromType(t.Elem(), basic{})

	return res
}