// Copyright (c) Microsoft Corporation. All rights reserved.

// Licensed under the MIT License.

'use strict';

export interface ITextRange {

readonly start: number;

readonly end: number;

readonly length: number;

contains(position: number): boolean;

}

export class TextRange implements ITextRange {

public static readonly empty = TextRange.fromBounds(0, 0);

public readonly start: number;

public readonly length: number;

constructor(start: number, length: number) {

if (start < 0) {

throw new Error('start must be non-negative');

}

if (length < 0) {

throw new Error('length must be non-negative');

}

this.start = start;

this.length = length;

}

public static fromBounds(start: number, end: number) {

return new TextRange(start, end - start);

}

public get end(): number {

return this.start + this.length;

}

public contains(position: number): boolean {

return position >= this.start && position < this.end;

}

}

export interface ITextRangeCollection<T> extends ITextRange {

count: number;

getItemAt(index: number): T;

getItemAtPosition(position: number): number;

getItemContaining(position: number): number;

}

export interface ITextIterator {

readonly length: number;

charCodeAt(index: number): number;

getText(): string;

}

export interface ICharacterStream extends ITextIterator {

position: number;

readonly currentChar: number;

readonly nextChar: number;

readonly prevChar: number;

getText(): string;

isEndOfStream(): boolean;

lookAhead(offset: number): number;

advance(offset: number): void;

moveNext(): boolean;

isAtWhiteSpace(): boolean;

isAtLineBreak(): boolean;

isAtString(): boolean;

skipLineBreak(): void;

skipWhitespace(): void;

skipToEol(): void;

skipToWhitespace(): void;

}

export enum TokenType {

Unknown,

String,

Comment,

Keyword,

Number,

Identifier,

Operator,

Colon,

Semicolon,

Comma,

OpenBrace,

CloseBrace,

OpenBracket,

CloseBracket,

OpenCurly,

CloseCurly

}

export interface IToken extends ITextRange {

readonly type: TokenType;

}

export enum TokenizerMode {

CommentsAndStrings,

Full

}

export interface ITokenizer {

tokenize(text: string): ITextRangeCollection<IToken>;

tokenize(text: string, start: number, length: number, mode: TokenizerMode): ITextRangeCollection<IToken>;

}