// dsh-plugin-mcn 视频/账号匹配工具（纯函数，拆分自 index.js）
import { homedir } from "node:os";
import { join } from "node:path";
import { readFileSync, existsSync } from "node:fs";

function normTitle(s) {
  return String(s || "").toLowerCase().replace(/[\s#，。！？、,.!?·\-_～~:："“”（）()【】]+/g, "");
}

function extractTopic(content) {
  const s = String(content || "");
  if (!s.trim()) return "";
  const lines = s.replace(/\r\n/g, "\n").split("\n");
  let start = -1;
  for (let i = 0; i < lines.length; i++) {
    const t = lines[i].trim();
    if (/^#{1,4}\s*选题\s*$/.test(t)) { start = i + 1; break; }
  }
  if (start < 0) return "";
  const out = [];
  for (let i = start; i < lines.length; i++) {
    const t = lines[i].trim();
    if (/^#{1,6}\s/.test(t) && !/^#{1,6}\s*选题\s*$/.test(t)) break;
    if (t) out.push(lines[i].trim());
  }
  return out.join("\n").trim();
}

function titleDistance(a, b) {
  const m = a.length, n = b.length;
  if (!m) return n;
  if (!n) return m;
  let prev = new Array(n + 1), curr = new Array(n + 1);
  for (let j = 0; j <= n; j++) prev[j] = j;
  for (let i = 1; i <= m; i++) {
    curr[0] = i;
    for (let j = 1; j <= n; j++) {
      curr[j] = Math.min(prev[j] + 1, curr[j - 1] + 1, prev[j - 1] + (a[i - 1] === b[j - 1] ? 0 : 1));
    }
    [prev, curr] = [curr, prev];
  }
  return prev[n];
}

function findVideoByFolder(d, accountId, vDir, vName) {
  const rows = d.prepare(`SELECT id, aweme_id, video_title FROM account_videos WHERE account_id=?`).all(accountId);
  const pick = (title) => {
    const t = String(title || "").trim();
    if (!t) return undefined;
    const exact = rows.find((r) => String(r.video_title || "") === t);
    if (exact) return exact;
    const tn = normTitle(t);
    if (!tn) return undefined;
    let best = null;
    for (const r of rows) {
      const cn = normTitle(r.video_title);
      if (!cn || cn.length < 6 || tn.length < 6) continue;
      if (tn.includes(cn) || cn.includes(tn)) {
        if (!best || tn.length > best.len) best = { id: r.id, aweme_id: r.aweme_id, len: tn.length };
      }
    }
    if (best) return best;
    let bestSim = null;
    for (const r of rows) {
      const cn = normTitle(r.video_title);
      if (!cn) continue;
      const ratio = 1 - titleDistance(tn, cn) / Math.max(tn.length, cn.length, 1);
      if (ratio > 0.8 && (!bestSim || ratio > bestSim.ratio)) bestSim = { id: r.id, aweme_id: r.aweme_id, ratio };
    }
    return bestSim ? bestSim : undefined;
  };
  for (const jf of ["原视频解析.json", "content.json"]) {
    const jp = join(vDir, jf);
    if (!existsSync(jp)) continue;
    try {
      const jd = JSON.parse(readFileSync(jp, "utf8"));
      const hit = pick(jd.title);
      if (hit) return hit;
    } catch (e) { /* 单个 json 解析失败不影响后续匹配 */ }
  }
  const first = String(vName || "").split("_")[0].trim();
  if (first) {
    const hit = pick(first);
    if (hit) return hit;
  }
  return undefined;
}

function resolveAccountDirs(acc) {
  const out = [];
  if (acc && typeof acc.source_dir === "string" && acc.source_dir && existsSync(acc.source_dir)) out.push(acc.source_dir);
  const legacy = acc && acc.account_name ? join(homedir(), "Desktop", "账号对标", acc.account_name) : null;
  if (legacy && existsSync(legacy)) out.push(legacy);
  return out;
}

function resolveAccountDir(acc) {
  return resolveAccountDirs(acc)[0] || null;
}

/** 数值化（非法输入返回 0） */
function num(v) {
  const n = Number(v);
  return Number.isFinite(n) ? n : 0;
}

export { num, normTitle, extractTopic, titleDistance, findVideoByFolder, resolveAccountDirs, resolveAccountDir };