import {
  renderLayout,
  renderPostCard,
  renderAdminCard,
  markdownPlaceholder,
  pageTitle
} from "./render.js";
import {
  escapeHtml,
  escapeAttr,
  formatDateTime,
  cleanText,
  isTruthy
} from "./utils.js";

export default {
  async fetch(request, env) {
    const url = new URL(request.url);
    const path = normalizePath(url.pathname);

    if (!env.DB) {
      return htmlResponse(renderLayout("配置缺失", `
        <h1>DB 绑定未配置</h1>
        <p>请先在 <code>wrangler.toml</code> 里配置 D1 数据库。</p>
      `, env), 500);
    }

    if (request.method === "OPTIONS") {
      return new Response(null, { headers: corsHeaders() });
    }

    try {
      if (path === "/admin/session" && request.method === "POST") {
        return await handleAdminSession(request, env);
      }

      if (request.method === "GET") {
        if (path === "/") return await handleIndex(env, url);
        if (path.startsWith("/post/")) return await handlePost(env, path.slice(6));
        if (path === "/admin" || path === "/admin/new" || path.startsWith("/admin/edit/")) {
          return await handleAdminPage(request, env, url, path);
        }
        if (path === "/api/posts") return await handleApiList(env, url);
        if (path.startsWith("/api/posts/")) return await handleApiRead(env, path.slice(11));
      }

      if (path === "/admin/save" && request.method === "POST") {
        return await handleAdminSave(request, env, url);
      }

      if (path === "/admin/delete" && request.method === "POST") {
        return await handleAdminDelete(request, env, url);
      }

      if (path === "/api/posts" && request.method === "POST") {
        return await handleApiCreate(request, env);
      }

      if (path.startsWith("/api/posts/")) {
        const idOrSlug = path.slice(11);
        if (request.method === "PUT") return await handleApiUpdate(request, env, idOrSlug);
        if (request.method === "DELETE") return await handleApiDelete(request, env, idOrSlug);
      }

      return notFoundPage(env);
    } catch (error) {
      return htmlResponse(renderLayout("错误", `
        <h1>发生错误</h1>
        <pre>${escapeHtml(error?.stack || error?.message || String(error))}</pre>
      `, env), 500);
    }
  }
};
async function handleIndex(env, url) {
  const q = (url.searchParams.get("q") || "").trim();
  const posts = await listPosts(env.DB, { publishedOnly: true, q });
  return htmlResponse(renderLayout(pageTitle(env, "首页"), `
    ${q ? `<p>搜索：<strong>${escapeHtml(q)}</strong></p>` : ""}
    ${posts.length ? posts.map(renderPostCard).join("") : "<p>暂无文章。</p>"}
  `, env));
}

async function handlePost(env, slug) {
  const post = await env.DB.prepare(
    "SELECT * FROM posts WHERE slug = ? AND published = 1 LIMIT 1"
  ).bind(decodeURIComponent(slug)).first();

  if (!post) return notFoundPage(env);

  await env.DB.prepare(
    "UPDATE posts SET view_count = COALESCE(view_count, 0) + 1 WHERE id = ?"
  ).bind(post.id).run();
  const views = (Number(post.view_count) || 0) + 1;

  return htmlResponse(renderLayout(`${post.title} - ${pageTitle(env)}`, `
    <p><a href="/">返回</a></p>
    <article>
      <h1>${escapeHtml(post.title)}</h1>
      <p class="post-detail-meta"><span class="post-detail-time">${formatDateTime(post.updated_at)}</span><span class="post-detail-views">浏览 ${views}</span></p>
      ${markdownPlaceholder(post.content)}
    </article>
  `, env, { markdownPage: true, cwdPostSlug: post.slug }));
}

async function handleAdminPage(request, env, url, path) {
  const auth = await requireAdmin(request, env);
  if (auth) return auth;

  let post = blankPost();
  if (path.startsWith("/admin/edit/")) {
    const id = Number(path.slice("/admin/edit/".length));
    if (Number.isFinite(id) && id > 0) {
      post = await getPostById(env.DB, id) || post;
    }
  } else if (path === "/admin" && url.searchParams.get("id")) {
    const id = Number(url.searchParams.get("id"));
    if (Number.isFinite(id) && id > 0) {
      post = await getPostById(env.DB, id) || post;
    }
  }

  const q = (url.searchParams.get("q") || "").trim();
  const posts = await listPosts(env.DB, { publishedOnly: false, q });

  return htmlResponse(renderLayout(`后台 - ${pageTitle(env)}`, `
    <p><a href="/">返回</a></p>
    <h1>后台</h1>
    <section>
      <h2>${post.id ? `编辑 #${post.id}` : "新建文章"}</h2>
      <form method="post" action="/admin/save">
        <input type="hidden" name="id" value="${escapeAttr(post.id || "")}">
        <p>
          <label>标题<br><input name="title" type="text" value="${escapeAttr(post.title || "")}" required></label>
        </p>
        <p>
          <label>Slug<br><input name="slug" type="text" value="${escapeAttr(post.slug || "")}"></label>
        </p>
        <p>
          <label>摘要<br><input name="excerpt" type="text" value="${escapeAttr(post.excerpt || "")}"></label>
        </p>
        <p>
          <label>内容<br><textarea name="content" required>${escapeHtml(post.content || "")}</textarea></label>
        </p>
        <p>
          <label><input name="published" type="checkbox" value="1" ${post.published ? "checked" : ""}> 发布</label>
        </p>
        <p><button type="submit">保存</button></p>
      </form>
    </section>

    <hr>

    <section>
      <h2>文章列表</h2>
      <form method="get" action="/admin">
        <p>
          <label>查询<br><input name="q" type="text" value="${escapeAttr(q)}"></label>
        </p>
        <p><button type="submit">搜索</button></p>
      </form>
      ${posts.length ? posts.map(renderAdminCard).join("") : "<p>没有找到文章。</p>"}
    </section>
  `, env));
}

async function handleAdminSave(request, env, url) {
  const auth = await requireAdmin(request, env);
  if (auth) return auth;

  const data = await readBody(request);
  const rawId = data.id ? Number(data.id) : null;
  const id = Number.isFinite(rawId) && rawId > 0 ? rawId : null;
  const title = cleanText(data.title);
  const content = cleanText(data.content);
  const excerpt = cleanText(data.excerpt);
  const slugBase = cleanText(data.slug) || title;
  const published = isTruthy(data.published) ? 1 : 0;

  if (!title || !content) {
    return htmlResponse(renderLayout("表单错误", `
      <h1>标题和内容不能为空</h1>
      <p><a href="/admin">返回后台</a></p>
    `, env), 400);
  }

  const slug = await uniqueSlug(env.DB, slugify(slugBase), id);
  const now = new Date().toISOString();

  if (id) {
    const exists = await getPostById(env.DB, id);
    if (!exists) return notFoundPage(env);
    await env.DB.prepare(`
      UPDATE posts
      SET title = ?, slug = ?, excerpt = ?, content = ?, published = ?, updated_at = ?
      WHERE id = ?
    `).bind(title, slug, excerpt, content, published, now, id).run();
  } else {
    const result = await env.DB.prepare(`
      INSERT INTO posts (title, slug, excerpt, content, published, created_at, updated_at)
      VALUES (?, ?, ?, ?, ?, ?, ?)
    `).bind(title, slug, excerpt, content, published, now, now).run();
    return Response.redirect(new URL(`/admin?id=${result.meta.last_row_id}&saved=1`, url), 303);
  }

  return Response.redirect(new URL(`/admin?id=${id}&saved=1`, url), 303);
}

async function handleAdminDelete(request, env, url) {
  const auth = await requireAdmin(request, env);
  if (auth) return auth;

  const data = await readBody(request);
  const id = Number(data.id);
  if (!Number.isFinite(id) || id <= 0) {
    return htmlResponse(renderLayout("表单错误", `
      <h1>无效的文章 ID</h1>
      <p><a href="/admin">返回后台</a></p>
    `, env), 400);
  }

  await env.DB.prepare("DELETE FROM posts WHERE id = ?").bind(id).run();
  return Response.redirect(new URL(`/admin?deleted=1`, url), 303);
}

async function handleAdminSession(request, env) {
  const password = cleanText(env.ADMIN_PASSWORD);
  if (!password) {
    return jsonResponse({ ok: false, error: "not_configured" }, 503);
  }

  const data = await readBody(request);
  const token = cleanText(data.token);
  if (token !== password) {
    return jsonResponse({ ok: false, error: "invalid" }, 401);
  }

  const value = await adminSessionCookieValue(env);
  const maxAge = 60 * 60 * 24 * 7;
  const secure = new URL(request.url).protocol === "https:";
  const parts = [`sb_admin=${value}`, "Path=/", "HttpOnly", "SameSite=Lax", `Max-Age=${maxAge}`];
  if (secure) parts.push("Secure");

  return jsonResponse({ ok: true }, 200, {
    "Set-Cookie": parts.join("; ")
  });
}

async function handleApiList(env, url) {
  const q = (url.searchParams.get("q") || "").trim();
  const posts = await listPosts(env.DB, { publishedOnly: false, q });
  return jsonResponse({ ok: true, posts });
}

async function handleApiRead(env, idOrSlug) {
  const post = await readPost(env.DB, idOrSlug);
  if (!post) return jsonResponse({ ok: false, error: "Not found" }, 404);
  return jsonResponse({ ok: true, post });
}

async function handleApiCreate(request, env) {
  const auth = await requireAdmin(request, env);
  if (auth) return auth;

  const data = await readBody(request);
  const created = await createOrUpdatePost(env.DB, data, null);
  return jsonResponse({ ok: true, post: created }, 201);
}

async function handleApiUpdate(request, env, idOrSlug) {
  const auth = await requireAdmin(request, env);
  if (auth) return auth;

  const data = await readBody(request);
  const existing = await readPost(env.DB, idOrSlug);
  if (!existing) return jsonResponse({ ok: false, error: "Not found" }, 404);
  const updated = await createOrUpdatePost(env.DB, data, existing.id);
  return jsonResponse({ ok: true, post: updated });
}

async function handleApiDelete(request, env, idOrSlug) {
  const auth = await requireAdmin(request, env);
  if (auth) return auth;

  const post = await readPost(env.DB, idOrSlug);
  if (!post) return jsonResponse({ ok: false, error: "Not found" }, 404);
  await env.DB.prepare("DELETE FROM posts WHERE id = ?").bind(post.id).run();
  return jsonResponse({ ok: true, deleted: post.id });
}

async function createOrUpdatePost(db, data, currentId) {
  const rawId = currentId ? Number(currentId) : null;
  const id = Number.isFinite(rawId) && rawId > 0 ? rawId : null;
  const title = cleanText(data.title);
  const content = cleanText(data.content);
  const excerpt = cleanText(data.excerpt);
  const slugBase = cleanText(data.slug) || title;
  const published = isTruthy(data.published) ? 1 : 0;

  if (!title || !content) {
    throw new Error("title 和 content 不能为空");
  }

  const slug = await uniqueSlug(db, slugify(slugBase), id);
  const now = new Date().toISOString();

  if (id) {
    await db.prepare(`
      UPDATE posts
      SET title = ?, slug = ?, excerpt = ?, content = ?, published = ?, updated_at = ?
      WHERE id = ?
    `).bind(title, slug, excerpt, content, published, now, id).run();
    return await getPostById(db, id);
  }

  const result = await db.prepare(`
    INSERT INTO posts (title, slug, excerpt, content, published, created_at, updated_at)
    VALUES (?, ?, ?, ?, ?, ?, ?)
  `).bind(title, slug, excerpt, content, published, now, now).run();
  return await getPostById(db, result.meta.last_row_id);
}

async function readPost(db, idOrSlug) {
  if (!idOrSlug) return null;
  const trimmed = decodeURIComponent(String(idOrSlug)).trim();
  if (/^\d+$/.test(trimmed)) {
    return await getPostById(db, Number(trimmed));
  }
  return await db.prepare("SELECT * FROM posts WHERE slug = ? LIMIT 1").bind(trimmed).first();
}

async function getPostById(db, id) {
  return await db.prepare("SELECT * FROM posts WHERE id = ? LIMIT 1").bind(Number(id)).first();
}

async function listPosts(db, { publishedOnly = true, q = "" } = {}) {
  const params = [];
  const where = [];
  if (publishedOnly) where.push("published = 1");
  if (q) {
    where.push("(title LIKE ? OR slug LIKE ? OR excerpt LIKE ? OR content LIKE ?)");
    const like = `%${q}%`;
    params.push(like, like, like, like);
  }
  const sql = `
    SELECT * FROM posts
    ${where.length ? `WHERE ${where.join(" AND ")}` : ""}
    ORDER BY published DESC, updated_at DESC, id DESC
  `;
  const statement = db.prepare(sql);
  const { results } = params.length ? await statement.bind(...params).all() : await statement.all();
  return results || [];
}

async function uniqueSlug(db, baseSlug, currentId) {
  let slug = baseSlug || "post";
  let suffix = 2;

  while (true) {
    const existing = await db.prepare("SELECT id FROM posts WHERE slug = ? LIMIT 1").bind(slug).first();
    if (!existing || Number(existing.id) === Number(currentId)) return slug;
    slug = `${baseSlug || "post"}-${suffix++}`;
  }
}

function slugify(value) {
  const raw = cleanText(value);
  const slug = raw
    .normalize("NFKD")
    .replace(/[\u0300-\u036f]/g, "")
    .replace(/[^\p{L}\p{N}]+/gu, "-")
    .replace(/^-+|-+$/g, "")
    .replace(/-+/g, "-")
    .toLowerCase();
  return slug || "post";
}
function normalizePath(pathname) {
  if (pathname === "/") return "/";
  return pathname.replace(/\/+$/, "");
}

function htmlResponse(html, status = 200, headers = {}) {
  return new Response(html, {
    status,
    headers: {
      "content-type": "text/html; charset=UTF-8",
      ...headers
    }
  });
}

function jsonResponse(data, status = 200, extraHeaders = {}) {
  return new Response(JSON.stringify(data, null, 2), {
    status,
    headers: {
      "content-type": "application/json; charset=UTF-8",
      ...corsHeaders(),
      ...extraHeaders
    }
  });
}

function notFoundPage(env) {
  return htmlResponse(renderLayout("404", `
    <h1>404</h1>
    <p>页面不存在。</p>
    <p><a href="/">返回</a></p>
  `, env), 404);
}

function corsHeaders() {
  return {
    "access-control-allow-origin": "*",
    "access-control-allow-methods": "GET, POST, PUT, DELETE, OPTIONS",
    "access-control-allow-headers": "*"
  };
}

async function requireAdmin(request, env) {
  const password = cleanText(env.ADMIN_PASSWORD);
  if (!password) return null;

  const cookies = parseCookie(request.headers.get("Cookie") || "");
  const expected = await adminSessionCookieValue(env);
  if (cookies.sb_admin && cookies.sb_admin === expected) {
    return null;
  }

  const header = request.headers.get("Authorization") || "";
  if (header.startsWith("Basic ")) {
    try {
      const decoded = atob(header.slice(6));
      const split = decoded.indexOf(":");
      const inputPassword = split >= 0 ? decoded.slice(split + 1) : "";
      if (inputPassword === password) return null;
    } catch {
      // ignore
    }
  }

  return unauthorized();
}

function parseCookie(header) {
  const out = {};
  if (!header) return out;
  for (const part of header.split(";")) {
    const idx = part.indexOf("=");
    if (idx === -1) continue;
    const k = part.slice(0, idx).trim();
    const v = part.slice(idx + 1).trim();
    try {
      out[k] = decodeURIComponent(v);
    } catch {
      out[k] = v;
    }
  }
  return out;
}

async function adminSessionCookieValue(env) {
  const password = cleanText(env.ADMIN_PASSWORD);
  const enc = new TextEncoder();
  const data = enc.encode(`${password}\0sproutblog_admin_v1`);
  const hash = await crypto.subtle.digest("SHA-256", data);
  return [...new Uint8Array(hash)].map((b) => b.toString(16).padStart(2, "0")).join("");
}

function unauthorized() {
  return new Response("Authentication required", {
    status: 401,
    headers: {
      "content-type": "text/plain; charset=UTF-8"
    }
  });
}

async function readBody(request) {
  const type = request.headers.get("content-type") || "";
  if (type.includes("application/json")) {
    return await request.json();
  }

  if (type.includes("multipart/form-data") || type.includes("application/x-www-form-urlencoded")) {
    const form = await request.formData();
    const data = {};
    for (const [key, value] of form.entries()) {
      data[key] = value;
    }
    return data;
  }

  return {};
}
function blankPost() {
  return {
    id: "",
    title: "",
    slug: "",
    excerpt: "",
    content: "",
    published: 1
  };
}

