import { NextRequest, NextResponse } from "next/server";
import { z } from "zod";
import { db, recipes, comments, users, userBlocks, eq, and, inArray } from "@epicure/db";
import { requireSession } from "@/lib/api-auth";
import { applyRateLimit } from "@/lib/rate-limit";
import { dispatchWebhook } from "@/lib/webhooks";
import { sendPushNotification } from "@/lib/push";
import { createNotification } from "@/lib/notifications";
import { isBlockedEitherWay } from "@/lib/blocks";
import { extractMentionedUsernames } from "@/lib/mentions";

const Schema = z.object({
  content: z.string().min(1).max(5000),
  parentId: z.string().optional(),
});

type Params = { params: Promise<{ id: string }> };

export async function GET(_req: NextRequest, { params }: Params) {
  const { id } = await params;
  const recipe = await db.query.recipes.findFirst({ where: eq(recipes.id, id) });
  if (!recipe || recipe.visibility === "private") {
    return NextResponse.json({ error: "Not found" }, { status: 404 });
  }

  const { session } = await requireSession();

  const rows = await db
    .select({
      id: comments.id,
      content: comments.content,
      parentId: comments.parentId,
      createdAt: comments.createdAt,
      updatedAt: comments.updatedAt,
      userId: comments.userId,
      userName: users.name,
      userUsername: users.username,
      userAvatarUrl: users.avatarUrl,
    })
    .from(comments)
    .innerJoin(users, eq(comments.userId, users.id))
    .where(eq(comments.recipeId, id))
    .orderBy(comments.createdAt);

  if (!session) return NextResponse.json(rows);

  const blocked = await db
    .select({ blockedId: userBlocks.blockedId })
    .from(userBlocks)
    .where(eq(userBlocks.blockerId, session.user.id));
  const blockedIds = new Set(blocked.map((b) => b.blockedId));

  return NextResponse.json(rows.filter((r) => !blockedIds.has(r.userId)));
}

export async function POST(req: NextRequest, { params }: Params) {
  const { session, response } = await requireSession();
  if (response) return response;
  const { id } = await params;

  const limited = await applyRateLimit(`rl:comment:${session!.user.id}`, 20, 60);
  if (limited) return limited;

  const recipe = await db.query.recipes.findFirst({ where: eq(recipes.id, id) });
  if (!recipe || (recipe.visibility === "private" && recipe.authorId !== session!.user.id)) {
    return NextResponse.json({ error: "Not found" }, { status: 404 });
  }

  if (recipe.authorId !== session!.user.id && await isBlockedEitherWay(session!.user.id, recipe.authorId)) {
    return NextResponse.json({ error: "Not found" }, { status: 404 });
  }

  const body = await req.json() as unknown;
  const parsed = Schema.safeParse(body);
  if (!parsed.success) return NextResponse.json({ error: "Validation error" }, { status: 400 });

  let parent: { id: string; userId: string } | undefined;
  if (parsed.data.parentId) {
    parent = await db.query.comments.findFirst({
      where: and(eq(comments.id, parsed.data.parentId), eq(comments.recipeId, id)),
    });
    if (!parent) return NextResponse.json({ error: "Parent comment not found" }, { status: 404 });
  }

  const commentId = crypto.randomUUID();
  await db.insert(comments).values({
    id: commentId,
    recipeId: id,
    userId: session!.user.id,
    parentId: parsed.data.parentId,
    content: parsed.data.content,
  });

  // Dispatch to recipe author's webhooks (not to the commenter themselves)
  if (recipe.authorId !== session!.user.id) {
    void dispatchWebhook(recipe.authorId, "comment.added", { commentId, recipeId: id, recipeTitle: recipe.title });
    void sendPushNotification(recipe.authorId, {
      title: "New comment on your recipe",
      body: `${session!.user.name} commented on "${recipe.title}"`,
      url: `/recipes/${id}`,
    });
  }

  if (parent && parent.userId !== session!.user.id) {
    void createNotification({ userId: parent.userId, type: "reply", actorId: session!.user.id, recipeId: id, commentId });
  }
  if (recipe.authorId !== parent?.userId) {
    void createNotification({ userId: recipe.authorId, type: "comment", actorId: session!.user.id, recipeId: id, commentId });
  }

  const mentionedUsernames = extractMentionedUsernames(parsed.data.content);
  if (mentionedUsernames.length > 0) {
    const alreadyNotified = new Set([recipe.authorId, parent?.userId].filter(Boolean));
    const mentionedUsers = await db
      .select({ id: users.id, username: users.username })
      .from(users)
      .where(inArray(users.username, mentionedUsernames));
    for (const mentioned of mentionedUsers) {
      if (alreadyNotified.has(mentioned.id)) continue;
      void createNotification({ userId: mentioned.id, type: "mention", actorId: session!.user.id, recipeId: id, commentId });
    }
  }

  return NextResponse.json({ id: commentId }, { status: 201 });
}