// The server-log tab's own filters in the address bar (`?page=activity&at=logs&lgrp=error&lreq=…`),
// so a filtered view — a request's lines, say — is a link. The filters every activity tab shares
// (time range, account, text) live in ./activityUrlState. Keys are namespaced (`l…`) like the Plex
// and Channels ones; setPage clears them (via ACTIVITY_KEYS) and the tab re-mirrors them while open.
import type { LevelGroup } from "./log";

export interface LogsUrlState {
  group: LevelGroup;
  sources: string[];
  /** An event code, or `none` for the rows without one. */
  event: string | null;
  requestId: string | null;
  jobId: number | null;
  /** A background run's lines (`job_runs.id`). */
  runId: number | null;
}

export const DEFAULT_LOGS_STATE: LogsUrlState = {
  group: "all",
  sources: [],
  event: null,
  requestId: null,
  jobId: null,
  runId: null,
};

export const LOGS_KEYS = ["lgrp", "lsrc", "lev", "lreq", "ljob", "lrun"] as const;

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 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 pick = (value: string | null, re: RegExp, max = 64) =>
  value && value.length <= max && re.test(value) ? value : null;
const positive = (value: string | null) =>
  value && /^\d{1,10}$/.test(value) && Number(value) > 0 ? Number(value) : null;

export function logsParamsToState(params: URLSearchParams): LogsUrlState {
  const group = params.get("lgrp");
  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),
    event: pick(params.get("lev"), EVENT_RE),
    requestId: pick(params.get("lreq"), REQUEST_RE),
    jobId: positive(params.get("ljob")),
    runId: positive(params.get("lrun")),
  };
}

/** 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,
    lev: state.event,
    lreq: state.requestId,
    ljob: state.jobId === null ? null : String(state.jobId),
    lrun: state.runId === null ? null : String(state.runId),
  };
}