import { dbGlobal } from "drizzle-pkg/lib/db";
import { users } from "drizzle-pkg/lib/schema/auth";
import { mediaRefs, posts } from "drizzle-pkg/lib/schema/content";
import { eq, inArray } from "drizzle-orm";
import { MEDIA_REF_OWNER_POST, MEDIA_REF_OWNER_PROFILE } from "#server/constants/media-refs";
import { extractMediaUrlsFromMarkdown, publicAssetUrlToStorageKey } from "#server/utils/post-media-urls";
import { allowedOriginsFromSitePublicEnv } from "#server/utils/site-public";

export type MediaRefContextDto = {
  ownerType: string;
  ownerId: number;
  /** 人类可读，如文章标题与位置、资料中的头像/简介 */
  label: string;
  /** 可跳转的站内路径；无权限或私密时为空 */
  href: string | null;
};

function extractUrls(markdown: string | null | undefined): string[] {
  return extractMediaUrlsFromMarkdown(markdown ?? "", {
    allowedAssetOrigins: allowedOriginsFromSitePublicEnv(),
  });
}

function postUsageParts(bodyMarkdown: string, coverUrl: string | null, storageKey: string): string[] {
  const parts: string[] = [];
  if (publicAssetUrlToStorageKey(coverUrl ?? "") === storageKey) {
    parts.push("封面");
  }
  if (extractUrls(bodyMarkdown).some((u) => publicAssetUrlToStorageKey(u) === storageKey)) {
    parts.push("正文 Markdown");
  }
  return parts;
}

function profileUsageParts(avatar: string | null, bioMarkdown: string | null, storageKey: string): string[] {
  const parts: string[] = [];
  if (publicAssetUrlToStorageKey(avatar ?? "") === storageKey) {
    parts.push("头像");
  }
  if (extractUrls(bioMarkdown).some((u) => publicAssetUrlToStorageKey(u) === storageKey)) {
    parts.push("简介 Markdown");
  }
  return parts;
}

function postHref(
  post: {
    id: number;
    userId: number;
    visibility: string;
    slug: string;
    authorPublicSlug: string | null;
  },
  viewerUserId: number,
): string | null {
  if (post.userId === viewerUserId) {
    return `/me/posts/${post.id}`;
  }
  if (post.visibility === "public" && post.authorPublicSlug) {
    return `/@${post.authorPublicSlug}/posts/${encodeURIComponent(post.slug)}`;
  }
  return null;
}

/**
 * 为一批资源构建引用上下文（文章 / 个人资料），用于媒体库与存储审计展示。
 */
export async function buildRefContextsForAssets(
  assets: Array<{ id: number; storageKey: string }>,
  viewer: { userId: number; role: string },
): Promise<Map<number, MediaRefContextDto[]>> {
  const map = new Map<number, MediaRefContextDto[]>();
  if (assets.length === 0) {
    return map;
  }
  const assetIds = assets.map((a) => a.id);
  const idToKey = new Map(assets.map((a) => [a.id, a.storageKey]));

  const refRows = await dbGlobal
    .select({
      assetId: mediaRefs.assetId,
      ownerType: mediaRefs.ownerType,
      ownerId: mediaRefs.ownerId,
    })
    .from(mediaRefs)
    .where(inArray(mediaRefs.assetId, assetIds));

  const refsByAsset = new Map<number, { ownerType: string; ownerId: number }[]>();
  for (const r of refRows) {
    const list = refsByAsset.get(r.assetId) ?? [];
    list.push({ ownerType: r.ownerType, ownerId: r.ownerId });
    refsByAsset.set(r.assetId, list);
  }

  const postIds = [...new Set(refRows.filter((r) => r.ownerType === MEDIA_REF_OWNER_POST).map((r) => r.ownerId))];
  const profileUserIds = [
    ...new Set(refRows.filter((r) => r.ownerType === MEDIA_REF_OWNER_PROFILE).map((r) => r.ownerId)),
  ];

  const postMap = new Map<
    number,
    {
      id: number;
      userId: number;
      title: string;
      slug: string;
      visibility: string;
      bodyMarkdown: string;
      coverUrl: string | null;
      authorPublicSlug: string | null;
    }
  >();
  if (postIds.length > 0) {
    const rows = await dbGlobal
      .select({
        id: posts.id,
        userId: posts.userId,
        title: posts.title,
        slug: posts.slug,
        visibility: posts.visibility,
        bodyMarkdown: posts.bodyMarkdown,
        coverUrl: posts.coverUrl,
        authorPublicSlug: users.publicSlug,
      })
      .from(posts)
      .innerJoin(users, eq(posts.userId, users.id))
      .where(inArray(posts.id, postIds));
    for (const p of rows) {
      postMap.set(p.id, p);
    }
  }

  const userMap = new Map<number, { id: number; username: string; avatar: string | null; bioMarkdown: string | null }>();
  if (profileUserIds.length > 0) {
    const urows = await dbGlobal
      .select({
        id: users.id,
        username: users.username,
        avatar: users.avatar,
        bioMarkdown: users.bioMarkdown,
      })
      .from(users)
      .where(inArray(users.id, profileUserIds));
    for (const u of urows) {
      userMap.set(u.id, u);
    }
  }

  for (const asset of assets) {
    const storageKey = idToKey.get(asset.id);
    if (!storageKey) {
      continue;
    }
    const refs = refsByAsset.get(asset.id) ?? [];
    const contexts: MediaRefContextDto[] = [];
    for (const r of refs) {
      if (r.ownerType === MEDIA_REF_OWNER_POST) {
        const p = postMap.get(r.ownerId);
        if (!p) {
          contexts.push({
            ownerType: r.ownerType,
            ownerId: r.ownerId,
            label: `文章 #${r.ownerId}（记录已不存在）`,
            href: null,
          });
          continue;
        }
        const usage = postUsageParts(p.bodyMarkdown, p.coverUrl, storageKey);
        const usageText = usage.length ? ` · ${usage.join("、")}` : "";
        contexts.push({
          ownerType: r.ownerType,
          ownerId: r.ownerId,
          label: `文章「${truncateTitle(p.title)}」${usageText}`,
          href: postHref(
            {
              id: p.id,
              userId: p.userId,
              visibility: p.visibility,
              slug: p.slug,
              authorPublicSlug: p.authorPublicSlug,
            },
            viewer.userId,
          ),
        });
      } else if (r.ownerType === MEDIA_REF_OWNER_PROFILE) {
        const u = userMap.get(r.ownerId);
        if (!u) {
          contexts.push({
            ownerType: r.ownerType,
            ownerId: r.ownerId,
            label: `个人资料用户 #${r.ownerId}（记录已不存在）`,
            href: null,
          });
          continue;
        }
        const slots = profileUsageParts(u.avatar, u.bioMarkdown, storageKey);
        const slotText = slots.length ? slots.join("、") : "图片";
        const href = viewer.userId === u.id ? "/me/profile" : null;
        contexts.push({
          ownerType: r.ownerType,
          ownerId: r.ownerId,
          label: `用户 @${u.username} 的个人资料 · ${slotText}`,
          href,
        });
      } else {
        contexts.push({
          ownerType: r.ownerType,
          ownerId: r.ownerId,
          label: `${r.ownerType} #${r.ownerId}`,
          href: null,
        });
      }
    }
    map.set(asset.id, contexts);
  }

  return map;
}

function truncateTitle(title: string, max = 48): string {
  const t = title.trim();
  if (t.length <= max) {
    return t;
  }
  return `${t.slice(0, max - 1)}…`;
}