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

// Licensed under the MIT License.

'use strict';

import { format } from 'winston';

import { isTestExecution } from '../common/constants';

import { getLevel, LogLevel, LogLevelName } from './levels';

const TIMESTAMP = 'YYYY-MM-DD HH:mm:ss';

// Knobs used when creating a formatter.

type FormatterOptions = {

label?: string;

};

// Pascal casing is used so log files get highlighted when viewing

// in VSC and other editors.

const formattedLogLevels: { [K in LogLevel]: string } = {

[LogLevel.Error]: 'Error',

[LogLevel.Warn]: 'Warn',

[LogLevel.Info]: 'Info',

[LogLevel.Debug]: 'Debug',

[LogLevel.Trace]: 'Trace',

};

// Return a consistent representation of the given log level.

function normalizeLevel(name: LogLevelName): string {

const level = getLevel(name);

if (level) {

const norm = formattedLogLevels[level];

if (norm) {

return norm;

}

}

return `${name.substring(0, 1).toUpperCase()}${name.substring(1).toLowerCase()}`;

}

// Return a log entry that can be emitted as-is.

function formatMessage(level: LogLevelName, timestamp: string, message: string): string {

const levelFormatted = normalizeLevel(level);

return isTestExecution()

? `${process.pid} ${levelFormatted} ${timestamp}: ${message}`

: `${levelFormatted} ${timestamp}: ${message}`;

}

// Return a log entry that can be emitted as-is.

function formatLabeledMessage(level: LogLevelName, timestamp: string, label: string, message: string): string {

const levelFormatted = normalizeLevel(level);

return isTestExecution()

? `${process.pid} ${levelFormatted} ${label} ${timestamp}: ${message}`

: `${levelFormatted} ${label} ${timestamp}: ${message}`;

}

// Return a minimal format object that can be used with a "winston"

// logging transport.

function getMinimalFormatter() {

return format.combine(

format.timestamp({ format: TIMESTAMP }),

format.printf(

// This relies on the timestamp formatter we added above:

({ level, message, timestamp }) => formatMessage(level as LogLevelName, timestamp, message),

),

);

}

// Return a minimal format object that can be used with a "winston"

// logging transport.

function getLabeledFormatter(label_: string) {

return format.combine(

format.label({ label: label_ }),

format.timestamp({ format: TIMESTAMP }),

format.printf(

// This relies on the label and timestamp formatters we added above:

({ level, message, label, timestamp }) =>

formatLabeledMessage(level as LogLevelName, timestamp, label, message),

),

);

}

// Return a format object that can be used with a "winston" logging transport.

export function getFormatter(opts: FormatterOptions = {}) {

if (opts.label) {

return getLabeledFormatter(opts.label);

}

return getMinimalFormatter();

}