import { env } from "process";
import { inspect } from "util";
import { bimap } from "../utils";

export interface Logger {
  trace(...objs: any[]): void;
  debug(...objs: any[]): void;
  info(...objs: any[]): void;
  warn(...objs: any[]): void;
  error(...objs: any[]): void;
}

const levels = bimap({ TRACE: 1, DEBUG: 2, INFO: 3, WARN: 4, ERROR: 5 });

class LoggerImpl implements Logger {
  private level: number;

  constructor(level: string) {
    this.level = levels[level] || 1000;
  }

  private log(level: number, objs: any[]) {
    if (this.level <= level) {
      const prefix: string = levels[level];
      const str = objs
        .map((obj, index) => {
          if (index === objs.length - 1 && obj instanceof Error) {
            if (this.level <= levels.DEBUG) {
              return obj.stack || obj;
            } else {
              return obj.message || obj;
            }
          }
          return obj;
        })
        .map(obj =>
          typeof obj === "object" ? inspect(obj, false, null, true) : obj
        );
      console.error.apply(console, [prefix, ...str]);
    }
  }

  trace = (...objs: any[]) => this.log(levels.TRACE, objs);
  debug = (...objs: any[]) => this.log(levels.DEBUG, objs);
  info = (...objs: any[]) => this.log(levels.INFO, objs);
  warn = (...objs: any[]) => this.log(levels.WARN, objs);
  error = (...objs: any[]) => this.log(levels.ERROR, objs);
}

export const logger: Logger = new LoggerImpl(
  env.NODE_ENV === "test" ? "" : (env.LOG_LEVEL || "INFO").toUpperCase()
);