import type {SembleCard, SembleCollection} from "../semble/types";

export interface ParsedSource {
  cards: SembleCard[];
  collections: SembleCollection[];
}

export function parseMarkdownSource(sourceId: string, text: string): ParsedSource {
  const lines = text.split(/\r?\n/);
  const cards: SembleCard[] = [];
  const collections: SembleCollection[] = [];
  let collection: string | undefined;

  for (let index = 0; index < lines.length; index += 1) {
    const line = lines[index];
    if (!line) continue;

    const headerMatch = line.match(/^#\s+(.+?)\s*$/);
    if (headerMatch) {
      collection = headerMatch[1]?.trim();
      if (collection) {
        const {description, nextIndex} = parseCollectionDescription(lines, index + 1);
        collections.push({
          name: collection,
          description,
          sourceId,
          line: index + 1
        });
        if (nextIndex > index + 1) {
          index = nextIndex - 1;
        }
      }
      continue;
    }

    const listMatch = line.match(/^\s*[-*]\s+(.+)$/);
    const candidate = listMatch ? listMatch[1] ?? "" : line.trim();
    const parsed = parseCardLine(candidate);
    if (!parsed) continue;

    const cardId = `${sourceId}#L${index + 1}:${parsed.url}`;
    cards.push({
      ...parsed,
      collection,
      sourceId,
      line: index + 1,
      id: cardId
    });
  }

  return {cards, collections};
}

function parseCollectionDescription(lines: string[], startIndex: number): {
  description?: string;
  nextIndex: number;
} {
  const descriptionParts: string[] = [];
  let index = startIndex;

  for (; index < lines.length; index += 1) {
    const line = lines[index] ?? "";
    const trimmed = line.trim();
    if (!trimmed) {
      if (descriptionParts.length > 0) {
        index += 1;
      }
      break;
    }
    if (/^#\s+/.test(trimmed) || /^\s*[-*]\s+/.test(trimmed)) {
      break;
    }
    descriptionParts.push(trimmed);
  }

  const description = descriptionParts.length > 0 ? descriptionParts.join(" ") : undefined;
  return {description, nextIndex: index};
}

function parseCardLine(text: string): Omit<SembleCard, "collection" | "sourceId" | "line" | "id"> | null {
  const trimmed = text.trim();
  if (!trimmed) return null;

  const splitIndex = trimmed.indexOf(" : ");
  const linkPart = splitIndex >= 0 ? trimmed.slice(0, splitIndex).trim() : trimmed;
  const notePart = splitIndex >= 0 ? trimmed.slice(splitIndex + 3).trim() : undefined;

  const markdownLink = linkPart.match(/^\[(.+?)\]\((.+?)\)$/);
  if (markdownLink) {
    const title = markdownLink[1]?.trim();
    const url = markdownLink[2]?.trim();
    if (!url) return null;
    return {
      url,
      title: title || undefined,
      note: notePart || undefined
    };
  }

  const angleLink = linkPart.match(/^<([^>]+)>$/);
  if (angleLink) {
    const url = angleLink[1]?.trim();
    if (!url) return null;
    return {
      url,
      note: notePart || undefined
    };
  }

  if (!/^(https?:\/\/|at:\/\/)\S+$/i.test(linkPart)) {
    return null;
  }

  return {
    url: linkPart,
    note: notePart || undefined
  };
}