/* eslint-disable no-use-before-define */
import { Interface, ToInterface, Cast, ToConstructor, HasTail, Head, Tail, ListSpec, ToType, DefaultFieldConstructor } from './Types';
import { Doc, FieldType } from './Doc';
import { ObjectField } from './ObjectField';
import { RefField } from './RefField';
import { SelfProxy } from './DocSymbols';
import { List } from './List';

type AllToInterface<T extends Interface[]> = {
    1: ToInterface<Head<T>> & AllToInterface<Tail<T>>;
    0: ToInterface<Head<T>>;
}[HasTail<T> extends true ? 1 : 0];

export const emptySchema = createSchema({});
export const Document = makeInterface(emptySchema);
export type Document = makeInterface<[typeof emptySchema]>;

export interface InterfaceFunc<T extends Interface[]> {
    (docs: Doc[]): makeInterface<T>[];
    (): makeInterface<T>;
    (doc: Doc): makeInterface<T>;
}

export type makeInterface<T extends Interface[]> = AllToInterface<T> & Doc & { proto: Doc | undefined };
export function makeInterface<T extends Interface[]>(...schemas: T): InterfaceFunc<T> {
    const schema: Interface = {};
    for (const s of schemas) {
        for (const key in s) {
            schema[key] = s[key];
        }
    }
    const proto = new Proxy(
        {},
        {
            get(target: unknown, prop, receiver) {
                const field = receiver.doc?.[prop];
                if (prop in schema) {
                    // eslint-disable-next-line @typescript-eslint/no-explicit-any
                    const desc = prop === 'proto' ? Doc : (schema as any)[prop]; // bcz: proto doesn't appear in schemas ... maybe it should?
                    if (typeof desc === 'object' && 'defaultVal' in desc && 'type' in desc) {
                        // defaultSpec
                        return Cast(field, desc.type, desc.defaultVal);
                    }
                    // eslint-disable-next-line no-prototype-builtins
                    if (typeof desc === 'function' && !ObjectField.isPrototypeOf(desc) && !RefField.isPrototypeOf(desc)) {
                        const doc = Cast(field, Doc);
                        if (doc === undefined) {
                            return undefined;
                        }
                        if (doc instanceof Doc) {
                            return desc(doc);
                        }
                        return doc.then(d => d && desc(d));
                    }
                    return Cast(field, desc);
                }
                return field;
            },
            set(target: unknown, prop, value, receiver) {
                receiver.doc && (receiver.doc[prop] = value); // receiver.doc may be undefined as the result of a change in acls
                return true;
            },
        }
    );
    // !(doc instanceof Doc) && (throw new Error("Currently wrapping a schema in another schema isn't supported"));
    const fn = (doc: Doc) => Object.create(proto, { doc: { value: doc[SelfProxy], writable: false } });
    return ((doc?: Doc | Doc[]) => (doc instanceof List ? doc : undefined)?.map?.(fn) ?? fn((doc as Doc) ?? new Doc())) as InterfaceFunc<T>;
}

export type makeStrictInterface<T extends Interface> = Partial<ToInterface<T>>;
export function makeStrictInterface<T extends Interface>(schema: T): (doc: Doc) => makeStrictInterface<T> {
    const proto = {};
    for (const key in schema) {
        const type = schema[key];
        Object.defineProperty(proto, key, {
            get() {
                return Cast(this.__doc[key], type as never);
            },
            set(setValue) {
                const value = Cast(setValue, type as never);
                if (value !== undefined) {
                    this.__doc[key] = value;
                    return;
                }
                throw new TypeError('Expected type ' + type);
            },
        });
    }
    return function (doc: unknown) {
        if (!(doc instanceof Doc)) {
            throw new Error("Currently wrapping a schema in another schema isn't supported");
        }
        const obj = Object.create(proto);
        obj.__doc = doc;
        return obj;
    };
}

// eslint-disable-next-line @typescript-eslint/no-unused-vars
export function createSchema<T extends Interface>(schema: T): T & { proto: ToConstructor<Doc> } {
    return undefined as never;
    // (schema as any).proto = Doc;
    // return schema as any;
}

export function listSpec<U extends ToConstructor<FieldType>>(type: U): ListSpec<ToType<U>> {
    return { List: type as never }; // TODO Types
}

export function defaultSpec<T extends ToConstructor<FieldType>>(type: T, defaultVal: ToType<T>): DefaultFieldConstructor<ToType<T>> {
    return {
        type: type as never,
        defaultVal,
    };
}