import { pad } from 'https://deno.land/std@0.36.0/strings/pad.ts';
import { FormatterFunction } from 'https://deno.land/std@0.151.0/log/handlers.ts';
import { LogRecord } from 'https://deno.land/std@0.151.0/log/logger.ts';

// See: https://github.com/denoland/deno_std/blob/0.151.0/log/README.md#custom-message-format
export const createFormatter = ({
  showTime = false,
  showLogger = false,
  showLevel = false,
  showLevelName = true,
  showBrackets = true,
  depth = 3,
} = {}): FormatterFunction => {
  const column = (value: string) => (showBrackets ? `[${value}]` : ` ${value}`);

  return ({ level, levelName, msg, args, loggerName }: LogRecord) => {
    let line = '';

    if (showLogger) {
      line += column(loggerName);
    }

    if (showTime) {
      const now = new Date();
      const hours = pad(`${now.getHours()}`, 2, { char: '0' });
      const minutes = pad(`${now.getMinutes()}`, 2, { char: '0' });
      const seconds = pad(`${now.getSeconds()}`, 2, { char: '0' });
      const time = [hours, minutes, seconds].join(':');
      line += column(time);
    }

    if (showLevelName) {
      const shortName = levelName.length <= 5 ? levelName : levelName.slice(0, 4);
      line += column(`${pad(shortName, 5, { side: 'left' })}`);
    }

    if (showLevel) {
      line += column(level);
    }

    if (msg) {
      if (line.length > 0) line += ' ';
      line += msg;
    }

    if (args) {
      if (line.length > 0) line += ' ';
      line += args
        .map((value) => {
          switch (typeof value) {
            case 'object':
              return Deno.inspect(value, { depth });
            case 'undefined':
              return 'undefined';
            default:
              return value;
          }
        })
        .join(' ');
    }

    return line;
  };
};

export const formatter = createFormatter();
export const consoleFormatter = createFormatter();
export const fileFormatter = createFormatter({ showTime: true, showLevel: true, showBrackets: false });