export type LogLevel = "debug" | "info" | "warn" | "error";

export interface LogRecord {
  level: LogLevel;
  msg: string;
  at: string;
  fields: Record<string, unknown>;
}

export type LogSink = (record: LogRecord) => void;

export interface TaskLogger {
  debug(msg: string, fields?: Record<string, unknown>): void;
  info(msg: string, fields?: Record<string, unknown>): void;
  warn(msg: string, fields?: Record<string, unknown>): void;
  error(msg: string, fields?: Record<string, unknown>): void;
  child(fields: Record<string, unknown>): TaskLogger;
}

const SENSITIVE_KEY = /pass(word|key)?|secret|token|cookie|authorization|api[-_]?key|credential|session/i;
// URL 查询参数里的凭证(passkey、token、apikey、sign 等)
const SENSITIVE_QUERY = /([?&](?:passkey|token|apikey|api_key|key|sign|secret|auth)=)[^&#\s]+/gi;
const REDACTED = "***";

/** 深拷贝并脱敏:敏感键名整体替换,字符串里的凭证型 URL 参数替换 */
export function redact(value: unknown, depth = 0): unknown {
  if (depth > 8) return "[depth]";
  if (typeof value === "string") return value.replace(SENSITIVE_QUERY, `$1${REDACTED}`);
  if (Array.isArray(value)) return value.map((v) => redact(v, depth + 1));
  if (value instanceof Error) return { name: value.name, message: redact(value.message, depth + 1) };
  if (value && typeof value === "object") {
    const out: Record<string, unknown> = {};
    for (const [k, v] of Object.entries(value)) out[k] = SENSITIVE_KEY.test(k) ? REDACTED : redact(v, depth + 1);
    return out;
  }
  return value;
}

export const consoleSink: LogSink = (r) => {
  const line = JSON.stringify(r);
  if (r.level === "error" || r.level === "warn") console.error(line);
  else console.log(line);
};

export const silentSink: LogSink = () => {};

export function createLogger(sink: LogSink = consoleSink, base: Record<string, unknown> = {}): TaskLogger {
  const emit =
    (level: LogLevel) =>
    (msg: string, fields: Record<string, unknown> = {}) =>
      sink({
        level,
        msg: redact(msg) as string,
        at: new Date().toISOString(),
        fields: redact({ ...base, ...fields }) as Record<string, unknown>,
      });
  return {
    debug: emit("debug"),
    info: emit("info"),
    warn: emit("warn"),
    error: emit("error"),
    child: (fields) => createLogger(sink, { ...base, ...fields }),
  };
}