import type { ItemSource, UnifiedItem } from "../shared/types.js";

export const LINE_WIDTH = 60;
export const PAGE_BODY_LINES = 24;

export function renderList(items: UnifiedItem[]): string {
  const lines: string[] = [`COUNT:${items.length}`, "==="];
  for (const it of items) {
    lines.push(`ID:${it.id}`);
    lines.push(`S:${it.source}`);
    lines.push(`R:${it.read ? 1 : 0}`);
    lines.push(`D:${it.fetchedAt}`);
    lines.push(`T:${singleLine(it.title)}`);
    if (it.publication) lines.push(`F:${singleLine(it.publication)}`);
    lines.push("===");
  }
  return lines.join("\n") + "\n";
}

export function renderItem(
  id: string,
  source: ItemSource,
  title: string,
  url: string,
  fetchedAt: number,
  body: string,
  page: number,
  publication?: string,
): string {
  const wrapped = wrapLines(body, LINE_WIDTH);
  const totalPages = Math.max(1, Math.ceil(wrapped.length / PAGE_BODY_LINES));
  const p = clamp(page, 1, totalPages);
  const start = (p - 1) * PAGE_BODY_LINES;
  const pageLines = wrapped.slice(start, start + PAGE_BODY_LINES);
  const header = [
    `ID:${id}`,
    `S:${source}`,
    `T:${singleLine(title)}`,
    `U:${singleLine(url)}`,
    `D:${fetchedAt}`,
    `P:${p}/${totalPages}`,
  ];
  if (publication) header.push(`F:${singleLine(publication)}`);
  return [...header, "---", ...pageLines, ""].join("\n");
}

function singleLine(s: string): string {
  return s.replace(/[\r\n]+/g, " ").trim();
}

function clamp(n: number, lo: number, hi: number): number {
  return Math.max(lo, Math.min(hi, n));
}

export function wrapLines(text: string, width: number): string[] {
  const paragraphs = text.split("\n");
  const out: string[] = [];
  for (const p of paragraphs) {
    const trimmed = p.trim();
    if (!trimmed) {
      out.push("");
      continue;
    }
    out.push(...wrapParagraph(trimmed, width));
  }
  return out;
}

function wrapParagraph(p: string, width: number): string[] {
  const words = p.split(/\s+/);
  const out: string[] = [];
  let cur = "";
  for (const w of words) {
    const cand = cur ? cur + " " + w : w;
    if (cand.length > width && cur) {
      out.push(cur);
      cur = w;
    } else {
      cur = cand;
    }
  }
  if (cur) out.push(cur);
  return out;
}