import {
  APIErrorCode,
  APIException,
  type Comment,
} from "../model/interfaces.ts";
import { type SQLOutputValue } from "node:sqlite";
import { commentRowToApi, db, isCommentRow } from "../model/db.ts";
import { notifyMentions } from "./notification-service.ts";

const SELECT_COLS =
  `c.id, c.dump_id, c.user_id, c.parent_id, c.body, c.created_at, c.updated_at, c.deleted,
  u.username as author_username, u.avatar_mime as author_avatar_mime`;

function fetchComment(commentId: string): Comment {
  const row = db.prepare(
    `SELECT ${SELECT_COLS} FROM comments c JOIN users u ON c.user_id = u.id WHERE c.id = ?;`,
  ).get(commentId);
  if (!row || !isCommentRow(row as Record<string, SQLOutputValue>)) {
    throw new APIException(APIErrorCode.NOT_FOUND, 404, "Comment not found");
  }
  if (!isCommentRow(row)) {
    throw new APIException(
      APIErrorCode.SERVER_ERROR,
      500,
      "Malformed comment data",
    );
  }
  return commentRowToApi(row);
}

export function getComments(dumpId: string): Comment[] {
  const rows = db.prepare(
    `SELECT ${SELECT_COLS} FROM comments c JOIN users u ON c.user_id = u.id
     WHERE c.dump_id = ? ORDER BY c.created_at ASC;`,
  ).all(dumpId);
  if (!rows.every(isCommentRow)) {
    throw new APIException(
      APIErrorCode.SERVER_ERROR,
      500,
      "Malformed comment data",
    );
  }
  return rows.map(commentRowToApi);
}

export function createComment(
  dumpId: string,
  userId: string,
  body: string,
  parentId?: string,
): Comment {
  const id = crypto.randomUUID();
  const createdAt = new Date();
  db.prepare(
    `INSERT INTO comments (id, dump_id, user_id, parent_id, body, created_at) VALUES (?, ?, ?, ?, ?, ?);`,
  ).run(
    id,
    dumpId,
    userId,
    parentId ?? null,
    body.trim(),
    createdAt.toISOString(),
  );
  const comment = fetchComment(id);
  const dumpRow = db.prepare(`SELECT title FROM dumps WHERE id = ?;`).get(
    dumpId,
  ) as { title: string } | undefined;
  notifyMentions(userId, body, "comment", id, dumpRow?.title ?? "", dumpId);
  return comment;
}

export function updateComment(
  commentId: string,
  body: string,
  requestingUserId: string,
  isAdmin: boolean,
): { comment: Comment; dumpId: string; isPrivate: boolean } {
  const row = db.prepare(
    `SELECT c.dump_id, d.is_private FROM comments c JOIN dumps d ON c.dump_id = d.id WHERE c.id = ?;`,
  ).get(commentId) as { dump_id: string; is_private: number } | undefined;
  if (!row) {
    throw new APIException(APIErrorCode.NOT_FOUND, 404, "Comment not found");
  }
  const existing = fetchComment(commentId);
  if (existing.deleted) {
    throw new APIException(
      APIErrorCode.VALIDATION_ERROR,
      400,
      "Cannot edit a deleted comment",
    );
  }
  if (existing.userId !== requestingUserId && !isAdmin) {
    throw new APIException(
      APIErrorCode.UNAUTHORIZED,
      401,
      "Not authorized to edit this comment",
    );
  }
  const now = new Date().toISOString();
  db.prepare(`UPDATE comments SET body = ?, updated_at = ? WHERE id = ?;`).run(
    body.trim(),
    now,
    commentId,
  );
  const dumpRow = db.prepare(`SELECT title FROM dumps WHERE id = ?;`).get(
    row.dump_id,
  ) as { title: string } | undefined;
  notifyMentions(
    requestingUserId,
    body,
    "comment",
    commentId,
    dumpRow?.title ?? "",
    row.dump_id,
  );
  return {
    comment: fetchComment(commentId),
    dumpId: row.dump_id,
    isPrivate: Boolean(row.is_private),
  };
}

export function deleteComment(
  commentId: string,
  requestingUserId: string,
  isAdmin: boolean,
): { dumpId: string; isPrivate: boolean } {
  const row = db.prepare(
    `SELECT c.dump_id, d.is_private FROM comments c JOIN dumps d ON c.dump_id = d.id WHERE c.id = ?;`,
  ).get(commentId) as { dump_id: string; is_private: number } | undefined;
  if (!row) {
    throw new APIException(APIErrorCode.NOT_FOUND, 404, "Comment not found");
  }
  const comment = fetchComment(commentId);
  if (comment.userId !== requestingUserId && !isAdmin) {
    throw new APIException(
      APIErrorCode.UNAUTHORIZED,
      401,
      "Not authorized to delete this comment",
    );
  }
  db.prepare(`UPDATE comments SET deleted = 1, body = '' WHERE id = ?;`).run(
    commentId,
  );
  return { dumpId: row.dump_id, isPrivate: Boolean(row.is_private) };
}