// Code originally derived from https://github.com/hadfieldn/node-bunyan-prettystream but since heavily edited
// Neither fork nor original repo appear to be maintained

import { Writable } from 'node:stream';
import * as util from 'node:util';
import { isNonEmptyObject, isPlainObject, isString } from '@sindresorhus/is';
import stringify from 'json-stringify-pretty-compact';
import { regEx } from '../util/regex.ts';
import type { BunyanRecord } from './types.ts';

const bunyanFields = [
  'name',
  'hostname',
  'pid',
  'level',
  'v',
  'time',
  'msg',
  'start_time',
];
/**
 * If a log contains any of these meta fields in the meta, promote them up to the log line, rather than rendering them with other meta fields.
 *
 * This only applies when these fields have a string value, otherwise they are treated as a regular meta field.
 */
const metaFields = [
  'repository',
  'baseBranch',
  'packageFile',
  'depType',
  'dependency',
  'branch',
];

const levels: Record<number, string> = {
  10: 'TRACE',
  20: 'DEBUG',
  30: ' INFO',
  40: ' WARN',
  50: 'ERROR',
  60: 'FATAL',
};

const colorizedLevels: Record<number, string> = {
  10: util.styleText('gray', 'TRACE'),
  20: util.styleText('blue', 'DEBUG'),
  30: util.styleText('green', ' INFO'),
  40: util.styleText('magenta', ' WARN'),
  50: util.styleText('red', 'ERROR'),
  60: util.styleText('bgRed', 'FATAL'),
};

export function indent(str: string, leading = false): string {
  const prefix = leading ? '       ' : '';
  return prefix + str.split(regEx(/\r?\n/)).join('\n       ');
}

export function getMeta(rec: BunyanRecord, colorize = true): string {
  if (!rec) {
    return '';
  }
  let res = rec.module ? ` [${rec.module}]` : ``;
  const filteredMeta = metaFields.filter((elem) => isString(rec[elem]));
  if (!filteredMeta.length) {
    return res;
  }
  const metaStr = filteredMeta
    .map((field) => `${field}=${String(rec[field])}`)
    .join(', ');
  res = ` (${metaStr})${res}`;
  return colorize ? util.styleText('gray', res) : res;
}

export function getDetails(rec: BunyanRecord): string {
  if (!rec) {
    return '';
  }
  const recFiltered = { ...rec };
  delete recFiltered.module;
  Object.keys(recFiltered).forEach((key) => {
    if (
      key === 'logContext' ||
      bunyanFields.includes(key) ||
      (metaFields.includes(key) && isString(recFiltered[key]))
    ) {
      delete recFiltered[key];
    }
  });
  const remainingKeys = Object.keys(recFiltered);
  if (remainingKeys.length === 0) {
    return '';
  }

  // Handle err.stack specially for readable multi-line output
  const err = recFiltered.err;
  if (isPlainObject(err) && isString(err.stack)) {
    const { stack, ...errRest } = err;
    recFiltered.err = isNonEmptyObject(errRest) ? errRest : undefined;
    const parts: string[] = [];
    for (const key of remainingKeys) {
      if (key === 'err' && recFiltered.err === undefined) {
        continue;
      }
      parts.push(indent(`"${key}": ${stringify(recFiltered[key])}`, true));
    }
    const jsonPart = parts.join(',\n');
    const stackPart = indent(stack, true);
    return jsonPart ? `${jsonPart}\n${stackPart}\n` : `${stackPart}\n`;
  }

  return `${remainingKeys
    .map((key) => `${indent(`"${key}": ${stringify(recFiltered[key])}`, true)}`)
    .join(',\n')}\n`;
}

export function formatRecord(rec: BunyanRecord, colorize = true): string {
  const level = colorize ? colorizedLevels[rec.level] : levels[rec.level];
  const msg = `${indent(rec.msg)}`;
  const meta = getMeta(rec, colorize);
  const details = getDetails(rec);
  return util.format('%s: %s%s\n%s', level, msg, meta, details);
}

export class PrettyStdoutStream extends Writable {
  constructor() {
    super({ objectMode: true });
  }

  override _write(
    data: BunyanRecord,
    _encoding: string,
    callback: (error?: Error | null) => void,
  ): void {
    process.stdout.write(formatRecord(data));
    callback();
  }
}