import { Term } from 'rethinkdbdash';

import { ColumnInfo } from './column';
import { assignWithArrays, pick as _pick } from './utils';
import { RethinkAdapter } from './adapter';
import { Hooks } from './hooks';
import { RelationshipInfo } from './relationships';

export const modelInfoKey = Symbol('rethink model info');

export interface ModelCtor<T> {
    new(): T;
}

export interface IndexInfo {
    name: string;
    keys: string[] | ((r: Term<any>) => any);
    options?: {
        multi?: boolean;
        geo?: boolean;
    }
}

export interface ModelInfo {
    database: string;
    table: string;
    columns: ColumnInfo[];
    indexes: IndexInfo[];
    primaryKey: string;
    tags: Map<string, Set<string>>;
    relationships: RelationshipInfo[];
}

export function createModelInfo(target: ModelCtor<any>, ...objs: Partial<ModelInfo>[]): ModelInfo {
    return target[modelInfoKey] = assignWithArrays(<Partial<ModelInfo>> {
        columns: [],
        indexes: [],
        relationships: [],
        primaryKey: 'id',
        tags: new Map<string, Set<string>>(),
    }, target[modelInfoKey], ...objs);
}

/**
 * Model decorator
 */
export function Model(info: Partial<ModelInfo>): ClassDecorator {
    return (target: ModelCtor<any>) => {
        const modelInfo = createModelInfo(target, info);

        target.prototype.toJSON = function () {
            return [...modelInfo.columns, ...modelInfo.relationships]
                .filter(column => this[column.key] !== undefined)
                .reduce((t, column) => ({ ...t, [column.key]: this[column.key] }), {});
        };
    };
}

function getKeys(ctor: ModelCtor<any>, tagsOrKeys: string[] | string): string[] {
    const modelTags = Model.getInfo(ctor).tags;

    let keys: string[];
    if (Array.isArray(tagsOrKeys)) {
        keys = tagsOrKeys;
    } else {
        keys = [tagsOrKeys];
    }

    return keys.reduce((keys, tagOrKey) => {
        if (modelTags.has(tagOrKey)) {
            return [...keys, ...modelTags.get(tagOrKey)];
        }

        return [...keys, tagOrKey];
    }, []);
}

export namespace Model {
    export function construct<M>(ctor: ModelCtor<M>, data: Partial<M>): M {
        return Model.assign(new ctor(), data);
    }

    export function assign<M>(model: M, ...sources: Partial<M>[]): M {
        return Object.assign(model, ...sources);
    }

    export function pickAssign<M>(model: M, tagsOrKeys: string[] | string, ...sources: Partial<M>[]): M {
        const ctor = <ModelCtor<M>> model.constructor;
        const keys = getKeys(ctor, tagsOrKeys) as Array<keyof M>;

        return Model.assign(model, ...sources.map(source => _pick(source, ...keys)));
    }

    export function pick<M>(model: M, ...tagsOrKeys: string[]): Partial<M> {
        const ctor = <ModelCtor<M>> model.constructor;
        const modelTags = Model.getInfo(ctor).tags;

        const data = tagsOrKeys.reduce((target, tagOrKey) => {
            if (modelTags.has(tagOrKey)) {
                return { ...target, ..._pick<M, any>(model, ...modelTags.get(tagOrKey)) };
            }

            return { ...target, [tagOrKey]: model[tagOrKey] };
        }, {});

        return Model.construct(ctor, data);
    }

    export function without<M>(model: M, ...tagsOrKeys: string[]): Partial<M> {
        const ctor = <ModelCtor<M>> model.constructor;

        const keys = getKeys(ctor, tagsOrKeys);

        const pickKeys = Object.keys(model)
            .filter(key => !keys.includes(key));

        return Model.construct(ctor, _pick<M, any>(model, ...pickKeys));
    }

    export function getInfo(ctor: ModelCtor<any>): ModelInfo {
        return ctor[modelInfoKey];
    }

    export function notify(model: any, hook: Hooks, ...args: any[]): any {
        if (model[hook]) {
            return model[hook](...args);
        }
    }
}