// Copyright (c) Microsoft Corporation.
// Licensed under the MIT License.

import type { languages } from 'monaco-editor-core';

const namedLiterals = ['true', 'false'];

export const conf: languages.LanguageConfiguration = {
	comments: {
		lineComment: '//',
		blockComment: ['/*', '*/']
	},
	brackets: [
		['{', '}'],
		['[', ']'],
		['(', ')'],
		['<', '>']
	],
	surroundingPairs: [
		{ open: '{', close: '}' },
		{ open: '[', close: ']' },
		{ open: '(', close: ')' },
		{ open: '<', close: '>' },
		{ open: '"', close: '"' },
		{ open: "'", close: "'" }
	],
	autoClosingPairs: [
		{ open: '{', close: '}' },
		{ open: '[', close: ']' },
		{ open: '(', close: ')' },
		{ open: '<', close: '>' },
		{ open: '"', close: '"', notIn: ['string'] },
		{ open: "'", close: "'", notIn: ['string'] }
	],
	autoCloseBefore: ".,=}])>' \n\t",
	indentationRules: {
		increaseIndentPattern: new RegExp('^((?!\\/\\/).)*(\\{[^}"\'`]*|\\([^)"\'`]*|\\[[^\\]"\'`]*)$'),
		decreaseIndentPattern: new RegExp('^((?!.*?\\/\\*).*\\*/)?\\s*[\\}\\]].*$')
	}
};

export const language = <languages.IMonarchLanguage>{
	defaultToken: '',
	tokenPostfix: '.proto',

	brackets: [
		{ open: '{', close: '}', token: 'delimiter.curly' },
		{ open: '[', close: ']', token: 'delimiter.square' },
		{ open: '(', close: ')', token: 'delimiter.parenthesis' },
		{ open: '<', close: '>', token: 'delimiter.angle' }
	],

	symbols: /[=><!~?:&|+\-*/^%]+/,

	keywords: [
		'syntax',
		'import',
		'weak',
		'public',
		'package',
		'option',
		'repeated',
		'oneof',
		'map',
		'reserved',
		'to',
		'max',
		'enum',
		'message',
		'service',
		'rpc',
		'stream',
		'returns',
		'package',
		'optional',
		'true',
		'false'
	],

	builtinTypes: [
		'double',
		'float',
		'int32',
		'int64',
		'uint32',
		'uint64',
		'sint32',
		'sint64',
		'fixed32',
		'fixed64',
		'sfixed32',
		'sfixed64',
		'bool',
		'string',
		'bytes'
	],

	operators: ['=', '+', '-'],

	namedLiterals,

	escapes: `\\\\(u{[0-9A-Fa-f]+}|n|r|t|\\\\|'|\\\${)`,
	identifier: /[a-zA-Z]\w*/,
	fullIdentifier: /@identifier(?:\s*\.\s*@identifier)*/,
	optionName: /(?:@identifier|\(\s*@fullIdentifier\s*\))(?:\s*\.\s*@identifier)*/,
	messageName: /@identifier/,
	enumName: /@identifier/,
	messageType: /\.?\s*(?:@identifier\s*\.\s*)*@messageName/,
	enumType: /\.?\s*(?:@identifier\s*\.\s*)*@enumName/,

	floatLit: /[0-9]+\s*\.\s*[0-9]*(?:@exponent)?|[0-9]+@exponent|\.[0-9]+(?:@exponent)?/,
	exponent: /[eE]\s*[+-]?\s*[0-9]+/,
	boolLit: /true\b|false\b/,

	decimalLit: /[1-9][0-9]*/,
	octalLit: /0[0-7]*/,
	hexLit: /0[xX][0-9a-fA-F]+/,

	type: /double|float|int32|int64|uint32|uint64|sint32|sint64|fixed32|fixed64|sfixed32|sfixed64|bool|string|bytes|@messageType|@enumType/,
	keyType: /int32|int64|uint32|uint64|sint32|sint64|fixed32|fixed64|sfixed32|sfixed64|bool|string/,

	tokenizer: {
		root: [
			{ include: '@whitespace' },
			[/syntax/, 'keyword'],
			[/=/, 'operators'],
			[/;/, 'delimiter'],
			[
				/(")(proto3)(")/,
				['string.quote', 'string', { token: 'string.quote', switchTo: '@topLevel.proto3' }]
			],
			[
				/(")(proto2)(")/,
				['string.quote', 'string', { token: 'string.quote', switchTo: '@topLevel.proto2' }]
			],
			[
				// If no `syntax` provided, regarded as proto2
				/.*?/,
				{ token: '', switchTo: '@topLevel.proto2' }
			]
		],

		topLevel: [
			// whitespace
			{ include: '@whitespace' },
			{ include: '@constant' },
			[/=/, 'operators'],
			[/[;.]/, 'delimiter'],
			[
				/@fullIdentifier/,
				{
					cases: {
						option: { token: 'keyword', next: '@option.$S2' },
						enum: { token: 'keyword', next: '@enumDecl.$S2' },
						message: { token: 'keyword', next: '@messageDecl.$S2' },
						service: { token: 'keyword', next: '@serviceDecl.$S2' },
						extend: {
							cases: {
								'$S2==proto2': { token: 'keyword', next: '@extendDecl.$S2' }
							}
						},
						'@keywords': 'keyword',
						'@default': 'identifier'
					}
				}
			]
		],

		enumDecl: [
			{ include: '@whitespace' },
			[/@identifier/, 'type.identifier'],
			[/{/, { token: '@brackets', bracket: '@open', switchTo: '@enumBody.$S2' }]
		],

		enumBody: [
			{ include: '@whitespace' },
			{ include: '@constant' },
			[/=/, 'operators'],
			[/;/, 'delimiter'],
			[/option\b/, 'keyword', '@option.$S2'],
			[/@identifier/, 'identifier'],
			[/\[/, { token: '@brackets', bracket: '@open', next: '@options.$S2' }],
			[/}/, { token: '@brackets', bracket: '@close', next: '@pop' }]
		],

		messageDecl: [
			{ include: '@whitespace' },
			[/@identifier/, 'type.identifier'],
			[/{/, { token: '@brackets', bracket: '@open', switchTo: '@messageBody.$S2' }]
		],

		messageBody: [
			{ include: '@whitespace' },
			{ include: '@constant' },
			[/=/, 'operators'],
			[/;/, 'delimiter'],
			[
				'(map)(s*)(<)',
				['keyword', 'white', { token: '@brackets', bracket: '@open', next: '@map.$S2' }]
			],
			[
				/@identifier/,
				{
					cases: {
						option: { token: 'keyword', next: '@option.$S2' },
						enum: { token: 'keyword', next: '@enumDecl.$S2' },
						message: { token: 'keyword', next: '@messageDecl.$S2' },
						oneof: { token: 'keyword', next: '@oneofDecl.$S2' },
						extensions: {
							cases: {
								'$S2==proto2': { token: 'keyword', next: '@reserved.$S2' }
							}
						},
						reserved: { token: 'keyword', next: '@reserved.$S2' },
						'(?:repeated|optional)': { token: 'keyword', next: '@field.$S2' },
						required: {
							cases: {
								'$S2==proto2': { token: 'keyword', next: '@field.$S2' }
							}
						},
						'$S2==proto3': { token: '@rematch', next: '@field.$S2' }
					}
				}
			],
			[/\[/, { token: '@brackets', bracket: '@open', next: '@options.$S2' }],
			[/}/, { token: '@brackets', bracket: '@close', next: '@pop' }]
		],

		extendDecl: [
			{ include: '@whitespace' },
			[/@identifier/, 'type.identifier'],
			[/{/, { token: '@brackets', bracket: '@open', switchTo: '@extendBody.$S2' }]
		],

		extendBody: [
			{ include: '@whitespace' },
			{ include: '@constant' },
			[/;/, 'delimiter'],
			[/(?:repeated|optional|required)/, 'keyword', '@field.$S2'],
			[/\[/, { token: '@brackets', bracket: '@open', next: '@options.$S2' }],
			[/}/, { token: '@brackets', bracket: '@close', next: '@pop' }]
		],

		options: [
			{ include: '@whitespace' },
			{ include: '@constant' },
			[/;/, 'delimiter'],
			[/@optionName/, 'annotation'],
			[/[()]/, 'annotation.brackets'],
			[/=/, 'operator'],
			[/\]/, { token: '@brackets', bracket: '@close', next: '@pop' }]
		],

		option: [
			{ include: '@whitespace' },
			[/@optionName/, 'annotation'],
			[/[()]/, 'annotation.brackets'],
			[/=/, 'operator', '@pop']
		],

		oneofDecl: [
			{ include: '@whitespace' },
			[/@identifier/, 'identifier'],
			[/{/, { token: '@brackets', bracket: '@open', switchTo: '@oneofBody.$S2' }]
		],

		oneofBody: [
			{ include: '@whitespace' },
			{ include: '@constant' },
			[/;/, 'delimiter'],
			[/(@identifier)(\s*)(=)/, ['identifier', 'white', 'delimiter']],
			[
				/@fullIdentifier|\./,
				{
					cases: {
						'@builtinTypes': 'keyword',
						'@default': 'type.identifier'
					}
				}
			],
			[/\[/, { token: '@brackets', bracket: '@open', next: '@options.$S2' }],
			[/}/, { token: '@brackets', bracket: '@close', next: '@pop' }]
		],

		reserved: [
			{ include: '@whitespace' },
			[/,/, 'delimiter'],
			[/;/, 'delimiter', '@pop'],
			{ include: '@constant' },
			[/to\b|max\b/, 'keyword']
		],

		map: [
			{ include: '@whitespace' },
			[
				/@fullIdentifier|\./,
				{
					cases: {
						'@builtinTypes': 'keyword',
						'@default': 'type.identifier'
					}
				}
			],
			[/,/, 'delimiter'],
			[/>/, { token: '@brackets', bracket: '@close', switchTo: 'identifier' }]
		],

		field: [
			{ include: '@whitespace' },
			[
				'group',
				{
					cases: {
						'$S2==proto2': { token: 'keyword', switchTo: '@groupDecl.$S2' }
					}
				}
			],
			[/(@identifier)(\s*)(=)/, ['identifier', 'white', { token: 'delimiter', next: '@pop' }]],
			[
				/@fullIdentifier|\./,
				{
					cases: {
						'@builtinTypes': 'keyword',
						'@default': 'type.identifier'
					}
				}
			]
		],

		groupDecl: [
			{ include: '@whitespace' },
			[/@identifier/, 'identifier'],
			['=', 'operator'],
			[/{/, { token: '@brackets', bracket: '@open', switchTo: '@messageBody.$S2' }],
			{ include: '@constant' }
		],

		type: [
			{ include: '@whitespace' },
			[/@identifier/, 'type.identifier', '@pop'],
			[/./, 'delimiter']
		],

		identifier: [{ include: '@whitespace' }, [/@identifier/, 'identifier', '@pop']],

		serviceDecl: [
			{ include: '@whitespace' },
			[/@identifier/, 'identifier'],
			[/{/, { token: '@brackets', bracket: '@open', switchTo: '@serviceBody.$S2' }]
		],

		serviceBody: [
			{ include: '@whitespace' },
			{ include: '@constant' },
			[/;/, 'delimiter'],
			[/option\b/, 'keyword', '@option.$S2'],
			[/rpc\b/, 'keyword', '@rpc.$S2'],
			[/\[/, { token: '@brackets', bracket: '@open', next: '@options.$S2' }],
			[/}/, { token: '@brackets', bracket: '@close', next: '@pop' }]
		],

		rpc: [
			{ include: '@whitespace' },
			[/@identifier/, 'identifier'],
			[/\(/, { token: '@brackets', bracket: '@open', switchTo: '@request.$S2' }],
			[/{/, { token: '@brackets', bracket: '@open', next: '@methodOptions.$S2' }],
			[/;/, 'delimiter', '@pop']
		],

		request: [
			{ include: '@whitespace' },
			[
				/@messageType/,
				{
					cases: {
						stream: { token: 'keyword', next: '@type.$S2' },
						'@default': 'type.identifier'
					}
				}
			],
			[/\)/, { token: '@brackets', bracket: '@close', switchTo: '@returns.$S2' }]
		],

		returns: [
			{ include: '@whitespace' },
			[/returns\b/, 'keyword'],
			[/\(/, { token: '@brackets', bracket: '@open', switchTo: '@response.$S2' }]
		],

		response: [
			{ include: '@whitespace' },
			[
				/@messageType/,
				{
					cases: {
						stream: { token: 'keyword', next: '@type.$S2' },
						'@default': 'type.identifier'
					}
				}
			],
			[/\)/, { token: '@brackets', bracket: '@close', switchTo: '@rpc.$S2' }]
		],

		methodOptions: [
			{ include: '@whitespace' },
			{ include: '@constant' },
			[/;/, 'delimiter'],
			['option', 'keyword'],
			[/@optionName/, 'annotation'],
			[/[()]/, 'annotation.brackets'],
			[/=/, 'operator'],
			[/}/, { token: '@brackets', bracket: '@close', next: '@pop' }]
		],

		comment: [
			[/[^\/*]+/, 'comment'],
			[/\/\*/, 'comment', '@push'], // nested comment
			['\\*/', 'comment', '@pop'],
			[/[\/*]/, 'comment']
		],

		string: [
			[/[^\\"]+/, 'string'],
			[/@escapes/, 'string.escape'],
			[/\\./, 'string.escape.invalid'],
			[/"/, { token: 'string.quote', bracket: '@close', next: '@pop' }]
		],

		stringSingle: [
			[/[^\\']+/, 'string'],
			[/@escapes/, 'string.escape'],
			[/\\./, 'string.escape.invalid'],
			[/'/, { token: 'string.quote', bracket: '@close', next: '@pop' }]
		],

		constant: [
			['@boolLit', 'keyword.constant'],
			['@hexLit', 'number.hex'],
			['@octalLit', 'number.octal'],
			['@decimalLit', 'number'],
			['@floatLit', 'number.float'],
			[/("([^"\\]|\\.)*|'([^'\\]|\\.)*)$/, 'string.invalid'], // non-terminated string
			[/"/, { token: 'string.quote', bracket: '@open', next: '@string' }],
			[/'/, { token: 'string.quote', bracket: '@open', next: '@stringSingle' }],
			[/{/, { token: '@brackets', bracket: '@open', next: '@prototext' }],
			[/identifier/, 'identifier']
		],

		whitespace: [
			[/[ \t\r\n]+/, 'white'],
			[/\/\*/, 'comment', '@comment'],
			[/\/\/.*$/, 'comment']
		],

		prototext: [
			{ include: '@whitespace' },
			{ include: '@constant' },
			[/@identifier/, 'identifier'],
			[/[:;]/, 'delimiter'],
			[/}/, { token: '@brackets', bracket: '@close', next: '@pop' }]
		]
	}
};