// Type definitions for levelup 5.1
// Project: https://github.com/Level/levelup
// Definitions by: Meirion Hughes <https://github.com/MeirionHughes>
//                 Daniel Byrne <https://github.com/danwbyrne>
//                 Carson Farmer <https://github.com/carsonfarmer>
//                 Steffen Park <https://github.com/istherepie>
// Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
// TypeScript Version: 2.3

/// <reference types="node" />

import { EventEmitter } from 'events';
import { AbstractLevelDOWN, AbstractIteratorOptions, AbstractBatch, ErrorCallback, AbstractOptions, ErrorValueCallback, AbstractGetOptions, AbstractIterator } from 'abstract-leveldown';
import { LevelUPError, InitializationError, OpenError, ReadError, WriteError, NotFoundError, EncodingError } from 'level-errors';

type LevelUpPut<K, V, O> =
    ((key: K, value: V, callback: ErrorCallback) => void) &
    ((key: K, value: V, options: O, callback: ErrorCallback) => void) &
    ((key: K, value: V, options?: O) => Promise<void>);

type LevelUpGet<K, V, O> =
    ((key: K, callback: ErrorValueCallback<V>) => void) &
    ((key: K, options: O, callback: ErrorValueCallback<V>) => void) &
    ((key: K, options?: O) => Promise<V>);

type LevelUpGetMany<K, V, O> =
    ((keys: K[], callback: ErrorValueCallback<V[]>) => void) &
    ((keys: K[], options: O, callback: ErrorValueCallback<V[]>) => void) &
    ((keys: K[], options?: O) => Promise<V[]>);

type LevelUpDel<K, O> =
    ((key: K, callback: ErrorCallback) => void) &
    ((key: K, options: O, callback: ErrorCallback) => void) &
    ((key: K, options?: O) => Promise<void>);

type LevelUpClear<O> =
    ((callback: ErrorCallback) => void) &
    ((options: O, callback: ErrorCallback) => void) &
    ((options?: O) => Promise<void>);

type LevelUpBatch<K, O> =
    ((key: K, callback: ErrorCallback) => void) &
    ((key: K, options: O, callback: ErrorCallback) => void) &
    ((key: K, options?: O) => Promise<void>);

type InferDBPut<DB> =
    DB extends { put: (key: infer K, value: infer V, options: infer O, cb: any) => void } ?
    LevelUpPut<K, V, O> :
    LevelUpPut<any, any, AbstractOptions>;

type InferDBGet<DB> =
    DB extends { get: (key: infer K, options: infer O, callback: ErrorValueCallback<infer V>) => void } ?
    LevelUpGet<K, V, O> :
    LevelUpGet<any, any, AbstractGetOptions>;

type InferDBGetMany<DB> =
    DB extends { getMany: (keys: Array<infer K>, options: infer O, callback: ErrorValueCallback<Array<infer V>>) => void } ?
    LevelUpGetMany<K, V, O> :
    LevelUpGetMany<any, any, AbstractGetOptions>;

type InferDBDel<DB> =
    DB extends { del: (key: infer K, options: infer O, callback: ErrorCallback) => void } ?
    LevelUpDel<K, O> :
    LevelUpDel<any, AbstractOptions>;

type InferDBClear<DB> =
    DB extends { clear: (options: infer O, callback: ErrorCallback) => void } ?
    LevelUpClear<O> :
    LevelUpClear<AbstractClearOptions>;

interface AbstractClearOptions<K = any> extends AbstractOptions {
    gt?: K | undefined;
    gte?: K | undefined;
    lt?: K | undefined;
    lte?: K | undefined;
    reverse?: boolean | undefined;
    limit?: number | undefined;
}

declare namespace levelup {
    interface LevelUpChain<K = any, V = any> {
        readonly length: number;
        put(key: K, value: V): this;
        del(key: K): this;
        clear(): this;
        write(callback: ErrorCallback): this;
        write(): Promise<this>;
    }
    interface LevelUp<DB = AbstractLevelDOWN, Iterator = AbstractIterator<any, any>> extends EventEmitter {
        open(): Promise<void>;
        open(callback?: ErrorCallback): void;
        close(): Promise<void>;
        close(callback?: ErrorCallback): void;

        put: InferDBPut<DB>;
        get: InferDBGet<DB>;
        del: InferDBDel<DB>;
        clear: InferDBClear<DB>;
        getMany: InferDBGetMany<DB>;

        batch(array: AbstractBatch[], options?: any): Promise<void>;
        batch(array: AbstractBatch[], options: any, callback: (err?: any) => any): void;
        batch(array: AbstractBatch[], callback: (err?: any) => any): void;

        batch(): LevelUpChain;
        iterator(options?: AbstractIteratorOptions): Iterator;

        isOpen(): boolean;
        isClosed(): boolean;

        readonly status: "closed" | "open" | "opening" | "new" | "closing";
        isOperational(): boolean;

        createReadStream(options?: AbstractIteratorOptions): NodeJS.ReadableStream;
        createKeyStream(options?: AbstractIteratorOptions): NodeJS.ReadableStream;
        createValueStream(options?: AbstractIteratorOptions): NodeJS.ReadableStream;

        /*
        emitted when a new value is 'put'
        */
        on(event: 'put', cb: (key: any, value: any) => void): this;
        /*
        emitted when a value is deleted
        */
        on(event: 'del', cb: (key: any) => void): this;
        /*
        emitted when a batch operation has executed
        */
        on(event: 'batch', cb: (ary: any[]) => void): this;
        /*
        emitted when clear is called
        */
        on(event: 'clear', cb: (opts: any) => void): this;
        /*
        emitted on given event
        */
        on(event: 'open' | 'ready' | 'closed' | 'opening' | 'closing', cb: () => void): this;
    }

    interface LevelUpConstructor {
        <DB extends AbstractLevelDOWN = AbstractLevelDOWN>(
            db: DB,
            options: any,
            cb?: ErrorCallback): LevelUp<DB>;

        <DB extends AbstractLevelDOWN = AbstractLevelDOWN>(
            db: DB,
            cb?: ErrorCallback): LevelUp<DB>;

        new <DB extends AbstractLevelDOWN = AbstractLevelDOWN>(
            db: DB,
            options: any,
            cb?: ErrorCallback): LevelUp<DB>;

        new <DB extends AbstractLevelDOWN = AbstractLevelDOWN>(
            db: DB,
            cb?: ErrorCallback): LevelUp<DB>;

        errors: {
            LevelUPError: typeof LevelUPError;
            InitializationError: typeof InitializationError;
            OpenError: typeof OpenError;
            ReadError: typeof ReadError;
            WriteError: typeof WriteError;
            NotFoundError: typeof NotFoundError;
            EncodingError: typeof EncodingError;
        };
    }
}

declare const levelup: levelup.LevelUpConstructor;

export = levelup;