import { OnTypeFormattingEditProvider, FormattingOptions, TextEdit, CancellationToken, TextDocument } from 'vscode';

import { Position } from 'vscode';

import { CodeBlockFormatProvider } from './codeBlockFormatProvider';

import { IF_REGEX, ELIF_REGEX, ELSE_REGEX, FOR_IN_REGEX, ASYNC_FOR_IN_REGEX, WHILE_REGEX } from './contracts';

import { TRY_REGEX, FINALLY_REGEX, EXCEPT_REGEX } from './contracts';

import { DEF_REGEX, ASYNC_DEF_REGEX, CLASS_REGEX } from './contracts';

export class BlockFormatProviders implements OnTypeFormattingEditProvider {

private providers: CodeBlockFormatProvider[];

constructor() {

this.providers = [];

const boundaryBlocks = [

DEF_REGEX,

ASYNC_DEF_REGEX,

CLASS_REGEX

];

const elseParentBlocks = [

IF_REGEX,

ELIF_REGEX,

FOR_IN_REGEX,

ASYNC_FOR_IN_REGEX,

WHILE_REGEX,

TRY_REGEX,

EXCEPT_REGEX

];

this.providers.push(new CodeBlockFormatProvider(ELSE_REGEX, elseParentBlocks, boundaryBlocks));

const elifParentBlocks = [

IF_REGEX,

ELIF_REGEX

];

this.providers.push(new CodeBlockFormatProvider(ELIF_REGEX, elifParentBlocks, boundaryBlocks));

const exceptParentBlocks = [

TRY_REGEX,

EXCEPT_REGEX

];

this.providers.push(new CodeBlockFormatProvider(EXCEPT_REGEX, exceptParentBlocks, boundaryBlocks));

const finallyParentBlocks = [

TRY_REGEX,

EXCEPT_REGEX

];

this.providers.push(new CodeBlockFormatProvider(FINALLY_REGEX, finallyParentBlocks, boundaryBlocks));

}

provideOnTypeFormattingEdits(document: TextDocument, position: Position, ch: string, options: FormattingOptions, token: CancellationToken): TextEdit[] {

if (position.line === 0) {

return [];

}

const currentLine = document.lineAt(position.line);

const prevousLine = document.lineAt(position.line - 1);

// We're only interested in cases where the current block is at the same indentation level as the previous line

// E.g. if we have an if..else block, generally the else statement would be at the same level as the code in the if...

if (currentLine.firstNonWhitespaceCharacterIndex !== prevousLine.firstNonWhitespaceCharacterIndex) {

return [];

}

const currentLineText = currentLine.text;

const provider = this.providers.find(provider => provider.canProvideEdits(currentLineText));

if (provider) {

return provider.provideEdits(document, position, ch, options, currentLine);

}

return [];

}

}