// The admin diagnostics console's filters in the address bar (`?page=logs&lgrp=error&lreq=…`), so a
// filtered view — a request's lines, say — is a link. Keys are namespaced (`l…`) like the Plex and
// Channels ones; setPage clears them (LOGS_KEYS) and the console re-mirrors them while it is open.
import type { LevelGroup } from "./log";

export type LogWindow = "1h" | "24h" | "7d";

export interface LogsUrlState {
  group: LevelGroup;
  sources: string[];
  /** An account id, or `none` for the rows without one. */
  user: string | null;
  /** An event code, or `none` for the rows without one. */
  event: string | null;
  requestId: string | null;
  jobId: number | null;
  q: string;
  window: LogWindow;
}

export const DEFAULT_LOGS_STATE: LogsUrlState = {
  group: "all",
  sources: [],
  user: null,
  event: null,
  requestId: null,
  jobId: null,
  q: "",
  window: "24h",
};

export const LOGS_KEYS = ["lgrp", "lsrc", "lu", "lev", "lreq", "ljob", "lq", "lwin"] as const;

export const WINDOW_HOURS: Record<LogWindow, number> = { "1h": 1, "24h": 24, "7d": 24 * 7 };

const GROUPS: readonly LevelGroup[] = ["all", "error", "warning", "info", "detail"];
// The same shapes the API validates: a link someone edited by hand degrades to "no filter" here
// instead of to a 422 on every request the console makes.
const USER_RE = /^(none|\d{1,10})$/;
const EVENT_RE = /^(none|[a-z][a-z0-9_]*(\.[a-z0-9_]+)*)$/;
const REQUEST_RE = /^[A-Za-z0-9._-]{8,64}$/;
const SOURCE_RE = /^[a-z]{1,16}$/;
const SOURCES_MAX = 8;
const Q_MAX = 200;

const pick = (value: string | null, re: RegExp, max = 64) =>
  value && value.length <= max && re.test(value) ? value : null;

export function logsParamsToState(params: URLSearchParams): LogsUrlState {
  const group = params.get("lgrp");
  const window = params.get("lwin");
  const job = params.get("ljob");
  return {
    group: GROUPS.includes(group as LevelGroup) ? (group as LevelGroup) : DEFAULT_LOGS_STATE.group,
    sources: (params.get("lsrc") ?? "")
      .split(",")
      .filter((s) => SOURCE_RE.test(s))
      .slice(0, SOURCES_MAX),
    user: pick(params.get("lu"), USER_RE),
    event: pick(params.get("lev"), EVENT_RE),
    requestId: pick(params.get("lreq"), REQUEST_RE),
    jobId: job && /^\d{1,10}$/.test(job) && Number(job) > 0 ? Number(job) : null,
    q: (params.get("lq") ?? "").slice(0, Q_MAX),
    window: window && window in WINDOW_HOURS ? (window as LogWindow) : DEFAULT_LOGS_STATE.window,
  };
}

/** The URL updates for a state: a filter at its default clears its key. */
export function logsParamUpdates(state: LogsUrlState): Record<string, string | null> {
  return {
    lgrp: state.group === DEFAULT_LOGS_STATE.group ? null : state.group,
    lsrc: state.sources.length ? state.sources.join(",") : null,
    lu: state.user,
    lev: state.event,
    lreq: state.requestId,
    ljob: state.jobId === null ? null : String(state.jobId),
    lq: state.q.trim() ? state.q : null,
    lwin: state.window === DEFAULT_LOGS_STATE.window ? null : state.window,
  };
}