import type { MsgTypeFilter } from './useMessageSearch';

/**
 * [Gitea #106] Discord-style operators typed into the search box. Each one
 * maps onto a filter the search already has (sender chips, room picker, date
 * range, "contains link", media type, pinned), so typing and clicking end up
 * in the same state. Pure and unit-tested.
 *
 *   from:@user            sender (existing)
 *   in:general  in:"a b"  room, by name or alias (resolved by the caller)
 *   after:2026-09-01      from the start of that day (local time)
 *   before:2026-09-01     up to the start of that day
 *   after:7d  before:2w   relative: h, d, w, m (30 d), y (365 d) ago
 *   has:link | image | video | file
 *   is:pinned
 */
export type ParsedSearch = {
  term: string;
  senders: string[];
  rooms: string[];
  fromTs?: number;
  toTs?: number;
  containsUrl?: boolean;
  msgTypes: MsgTypeFilter[];
  pinnedOnly?: boolean;
  /** Operators we didn't understand, left in the term as typed. */
  unknown: string[];
};

const UNIT_MS: Record<string, number> = {
  h: 3_600_000,
  d: 86_400_000,
  w: 7 * 86_400_000,
  m: 30 * 86_400_000,
  y: 365 * 86_400_000,
};

/** A date operand → timestamp, or undefined if it isn't one. Exported for tests. */
export function parseDateOperand(value: string, now: number): number | undefined {
  const rel = /^(\d{1,4})([hdwmy])$/i.exec(value);
  if (rel) return now - Number(rel[1]) * UNIT_MS[rel[2].toLowerCase()];
  const abs = /^(\d{4})-(\d{1,2})-(\d{1,2})$/.exec(value);
  if (abs) {
    const [y, m, d] = [Number(abs[1]), Number(abs[2]), Number(abs[3])];
    const date = new Date(y, m - 1, d);
    if (date.getFullYear() !== y || date.getMonth() !== m - 1 || date.getDate() !== d) {
      return undefined;
    }
    return date.getTime();
  }
  return undefined;
}

const HAS_TYPES: Record<string, MsgTypeFilter> = {
  image: 'm.image',
  images: 'm.image',
  video: 'm.video',
  videos: 'm.video',
  file: 'm.file',
  files: 'm.file',
};

// key:"quoted value" or key:value
const OPERATOR = /(^|\s)(from|in|after|before|has|is):(?:"([^"]*)"|(\S*))/gi;

export function parseSearchQuery(raw: string, now = Date.now()): ParsedSearch {
  const out: ParsedSearch = { term: '', senders: [], rooms: [], msgTypes: [], unknown: [] };
  const kept: string[] = [];
  let last = 0;
  raw.replace(
    OPERATOR,
    (match, lead: string, keyRaw: string, quoted?: string, bare?: string, offset?: number) => {
      const key = keyRaw.toLowerCase();
      const value = (quoted ?? bare ?? '').trim();
      const start = (offset ?? 0) + lead.length;
      kept.push(raw.slice(last, start));
      last = start + match.length - lead.length;
      let understood = value !== '';
      if (understood) {
        if (key === 'from') {
          out.senders.push(value.startsWith('@') ? value : `@${value}`);
        } else if (key === 'in') {
          out.rooms.push(value);
        } else if (key === 'after' || key === 'before') {
          const ts = parseDateOperand(value, now);
          if (ts === undefined) understood = false;
          else if (key === 'after') out.fromTs = ts;
          else out.toTs = ts;
        } else if (key === 'has') {
          const v = value.toLowerCase();
          if (v === 'link' || v === 'links' || v === 'url') out.containsUrl = true;
          else if (HAS_TYPES[v]) {
            if (!out.msgTypes.includes(HAS_TYPES[v])) out.msgTypes.push(HAS_TYPES[v]);
          } else understood = false;
        } else if (key === 'is') {
          if (value.toLowerCase() === 'pinned') out.pinnedOnly = true;
          else understood = false;
        }
      }
      if (!understood) {
        out.unknown.push(match.trim());
        kept.push(match.trim());
      }
      return match;
    },
  );
  kept.push(raw.slice(last));
  out.term = kept.join(' ').replace(/\s+/g, ' ').trim();
  return out;
}

/** True when the query contains any operator at all (for the submit path). */
export const hasOperators = (p: ParsedSearch): boolean =>
  p.senders.length > 0 ||
  p.rooms.length > 0 ||
  p.fromTs !== undefined ||
  p.toTs !== undefined ||
  !!p.containsUrl ||
  p.msgTypes.length > 0 ||
  !!p.pinnedOnly;

/** Resolve an `in:` value to a room id among `rooms`. Exported for tests. */
export function resolveRoomOperand(
  value: string,
  rooms: { roomId: string; name: string; aliases: string[] }[],
): string | undefined {
  const v = value.toLowerCase().replace(/^#/, '');
  const exact = rooms.find(
    (r) =>
      r.roomId.toLowerCase() === value.toLowerCase() ||
      r.aliases.some((a) => {
        const al = a.toLowerCase().replace(/^#/, '');
        return al === v || al.split(':')[0] === v;
      }) ||
      r.name.toLowerCase() === v,
  );
  if (exact) return exact.roomId;
  const partial = rooms.filter((r) => r.name.toLowerCase().includes(v));
  return partial.length === 1 ? partial[0].roomId : undefined;
}