export const SELECT_POST = 'SELECT_POST';
export const UNSELECT_POST = 'UNSELECT_POST';

export const RECEIVE_POSTS = 'RECEIVE_POSTS';
export const RECEIVE_POST = 'RECEIVE_POST';
export const REQUEST_POSTS = 'REQUEST_POSTS';

export const MARK_POST_READ = 'MARK_POST_READ';

export const selectPost = post => ({
  type: SELECT_POST,
  post,
});

export const unSelectPost = () => ({
  type: UNSELECT_POST,
});

export const postRead = (post, rule, category) => ({
  type: MARK_POST_READ,
  category: category,
  post: post,
  rule: rule,
});

export const markPostRead = (post, token) => {
  return (dispatch, getState) => {
    const { rules } = getState();
    const { categories } = getState();

    const url = `/api/posts/${post.id}/`;
    const options = {
      method: 'PATCH',
      headers: {
        'Content-Type': 'application/json',
        'X-CSRFToken': token,
      },
      body: JSON.stringify({ read: true }),
    };

    const rule = rules.items[post.rule];
    const category = categories.items[rule.category];

    return fetch(url, options)
      .then(response => response.json())
      .then(updatedPost => {
        const updatedRule = { ...rule, unread: rule.unread - 1 };
        const updatedCategory = { ...category, unread: category.unread - 1 };

        dispatch(receivePost({ ...updatedPost }));
        dispatch(postRead({ ...updatedPost }, updatedRule, updatedCategory));
      });
  };
};

export const receivePosts = json => ({
  type: RECEIVE_POSTS,
  posts: json.items,
  next: json.next,
});

export const receivePost = post => ({
  type: RECEIVE_POST,
  post,
});

export const requestPosts = () => ({ type: REQUEST_POSTS });

export const fetchPostsByCategory = (category, page = false) => {
  return dispatch => {
    dispatch(requestPosts());

    const url = page ? page : `/api/categories/${category.id}/posts/?read=false`;
    return fetch(url)
      .then(response => response.json())
      .then(json => {
        const posts = {};

        json.results.forEach(post => {
          posts[post.id] = post;
        });

        dispatch(receivePosts({ items: posts, next: json.next }));
      })
      .catch(error => {
        if (error instanceof TypeError) {
          console.log(`Unable to parse posts from request: ${error}`);
        }

        dispatch(receivePosts({ items: {}, next: null }));
      });
  };
};

export const fetchPostsByRule = (rule, page = false) => {
  return dispatch => {
    dispatch(requestPosts());

    const url = page ? page : `/api/rules/${rule.id}/posts/?read=false`;
    return fetch(url)
      .then(response => response.json())
      .then(json => {
        const posts = {};

        json.results.forEach(post => {
          posts[post.id] = post;
        });

        dispatch(receivePosts({ items: posts, next: json.next }));
      })
      .catch(error => {
        if (error instanceof TypeError) {
          console.log(`Unable to parse posts from request: ${error}`);
        }

        dispatch(receivePosts({ items: {}, next: null }));
      });
  };
};