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// Copyright 2018-2024 the Deno authors. All rights reserved. MIT license.// This module is browser compatible.import { getLevelByName, getLevelName, LogLevels } from "./levels.ts";import type { LevelName, LogLevel } from "./levels.ts";import type { BaseHandler } from "./base_handler.ts";
// deno-lint-ignore no-explicit-anyexport type GenericFunction = (...args: any[]) => any;
export interface LogRecordOptions {  msg: string;  args: unknown[];  level: LogLevel;  loggerName: string;}
export class LoggerConfig {  level?: LevelName;  handlers?: string[];}
export interface LogConfig {  handlers?: {    [name: string]: BaseHandler;  };  loggers?: {    [name: string]: LoggerConfig;  };}
/** * An object that encapsulates provided message and arguments as well some * metadata that can be later used when formatting a message. */export class LogRecord {  readonly msg: string;  #args: unknown[];  #datetime: Date;  readonly level: number;  readonly levelName: string;  readonly loggerName: string;
  constructor(options: LogRecordOptions) {    this.msg = options.msg;    this.#args = [...options.args];    this.level = options.level;    this.loggerName = options.loggerName;    this.#datetime = new Date();    this.levelName = getLevelName(options.level);  }  get args(): unknown[] {    return [...this.#args];  }  get datetime(): Date {    return new Date(this.#datetime.getTime());  }}
export interface LoggerOptions {  handlers?: BaseHandler[];}
export class Logger {  #level: LogLevel;  handlers: BaseHandler[];  readonly #loggerName: string;
  constructor(    loggerName: string,    levelName: LevelName,    options: LoggerOptions = {},  ) {    this.#loggerName = loggerName;    this.#level = getLevelByName(levelName);    this.handlers = options.handlers || [];  }
  /** Use this to retrieve the current numeric log level. */  get level(): LogLevel {    return this.#level;  }
  /** Use this to set the numeric log level. */  set level(level: LogLevel) {    try {      this.#level = getLevelByName(getLevelName(level));    } catch (_) {      throw new TypeError(`Invalid log level: ${level}`);    }  }
  get levelName(): LevelName {    return getLevelName(this.#level);  }  set levelName(levelName: LevelName) {    this.#level = getLevelByName(levelName);  }
  get loggerName(): string {    return this.#loggerName;  }
  /**   * If the level of the logger is greater than the level to log, then nothing   * is logged, otherwise a log record is passed to each log handler.  `msg` data   * passed in is returned.  If a function is passed in, it is only evaluated   * if the msg will be logged and the return value will be the result of the   * function, not the function itself, unless the function isn't called, in which   * case undefined is returned.  All types are coerced to strings for logging.   */  #log<T>(    level: LogLevel,    msg: (T extends GenericFunction ? never : T) | (() => T),    ...args: unknown[]  ): T | undefined {    if (this.level > level) {      return msg instanceof Function ? undefined : msg;    }
    let fnResult: T | undefined;    let logMessage: string;    if (msg instanceof Function) {      fnResult = msg();      logMessage = this.asString(fnResult);    } else {      logMessage = this.asString(msg);    }    const record: LogRecord = new LogRecord({      msg: logMessage,      args: args,      level: level,      loggerName: this.loggerName,    });
    this.handlers.forEach((handler) => {      handler.handle(record);    });
    return msg instanceof Function ? fnResult : msg;  }
  asString(data: unknown, isProperty = false): string {    if (typeof data === "string") {      if (isProperty) return `"${data}"`;      return data;    } else if (      data === null ||      typeof data === "number" ||      typeof data === "bigint" ||      typeof data === "boolean" ||      typeof data === "undefined" ||      typeof data === "symbol"    ) {      return String(data);    } else if (data instanceof Error) {      return data.stack!;    } else if (typeof data === "object") {      return `{${        Object.entries(data)          .map(([k, v]) => `"${k}":${this.asString(v, true)}`)          .join(",")      }}`;    }    return "undefined";  }
  debug<T>(msg: () => T, ...args: unknown[]): T | undefined;  debug<T>(msg: T extends GenericFunction ? never : T, ...args: unknown[]): T;  debug<T>(    msg: (T extends GenericFunction ? never : T) | (() => T),    ...args: unknown[]  ): T | undefined {    return this.#log(LogLevels.DEBUG, msg, ...args);  }
  info<T>(msg: () => T, ...args: unknown[]): T | undefined;  info<T>(msg: T extends GenericFunction ? never : T, ...args: unknown[]): T;  info<T>(    msg: (T extends GenericFunction ? never : T) | (() => T),    ...args: unknown[]  ): T | undefined {    return this.#log(LogLevels.INFO, msg, ...args);  }
  warn<T>(msg: () => T, ...args: unknown[]): T | undefined;  warn<T>(msg: T extends GenericFunction ? never : T, ...args: unknown[]): T;  warn<T>(    msg: (T extends GenericFunction ? never : T) | (() => T),    ...args: unknown[]  ): T | undefined {    return this.#log(LogLevels.WARN, msg, ...args);  }
  error<T>(msg: () => T, ...args: unknown[]): T | undefined;  error<T>(msg: T extends GenericFunction ? never : T, ...args: unknown[]): T;  error<T>(    msg: (T extends GenericFunction ? never : T) | (() => T),    ...args: unknown[]  ): T | undefined {    return this.#log(LogLevels.ERROR, msg, ...args);  }
  critical<T>(msg: () => T, ...args: unknown[]): T | undefined;  critical<T>(    msg: T extends GenericFunction ? never : T,    ...args: unknown[]  ): T;  critical<T>(    msg: (T extends GenericFunction ? never : T) | (() => T),    ...args: unknown[]  ): T | undefined {    return this.#log(LogLevels.CRITICAL, msg, ...args);  }}