// posts.ts
// Copyright (C) 2020  Dwayne Harris

// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <https://www.gnu.org/licenses/>.


import { apiFetch } from '../api'
import { setEntities } from '../actions/entities'
import { listSet, listAppend } from '../actions/lists'
import { startRequest, finishRequest } from '../actions/requests'

import { objectToQuerystring } from '../utils'
import { normalize } from '../utils/normalization'
import { AppThunkAction, Entity, RequestKey, EntityType, User, Post, Attachment, EntityListKey } from '../types'

interface CreatePostResponse {
    id: string
}

interface CreatePostOptions {
    installation: string
    visible: boolean
    text?: string
    cover?: string
    attachments: Attachment[]
    data?: object
    parent?: string
}

export const createPost = (options: CreatePostOptions): AppThunkAction<string> => {
    return async dispatch => {
        const { installation, visible, text, cover, attachments, data, parent } = options
        dispatch(startRequest(RequestKey.CreatePost))

        try {
            const post = await apiFetch<CreatePostResponse>({
                path: `/v1/post`,
                method: 'post',
                body: {
                    installation,
                    visible,
                    text,
                    cover,
                    attachments,
                    data,
                    parent,
                },
            })

            dispatch(finishRequest(RequestKey.CreatePost, true))
            return post.id
        } catch (err) {
            dispatch(finishRequest(RequestKey.CreatePost, false))
            throw err
        }
    }
}

interface FetchPostResponse {
    post: Post,
    parents: Post[],
    children: Post[],
    users: User[],
}

export const fetchPost = (id: string): AppThunkAction => {
    return async dispatch => {
        dispatch(startRequest(RequestKey.FetchPost))

        try {
            const response = await apiFetch<FetchPostResponse>({
                path: `/v1/post/${id}`
            })

            const parents = normalize(response.parents.map(p => ({
                ...p,
                user: response.users.find(u => u.id === p.userId),
                userId: undefined,
            })), EntityType.Post)

            dispatch(setEntities(parents.entities))
            dispatch(listSet(`post:${id}:parents`, parents.keys))

            const children = normalize(response.children.map(p => ({
                ...p,
                user: response.users.find(u => u.id === p.userId),
                userId: undefined,
            })), EntityType.Post)

            dispatch(setEntities(children.entities))
            dispatch(listSet(`post:${id}:children`, children.keys))

            const post: Entity = {
                ...response.post,
                user: response.users.find(u => u.id === response.post.userId),
                userId: undefined,
            }

            const posts = normalize([post], EntityType.Post)
            dispatch(setEntities(posts.entities))

            dispatch(finishRequest(RequestKey.FetchPost, true))
        } catch (err) {
            dispatch(finishRequest(RequestKey.FetchPost, false))
            throw err
        }
    }
}

interface TimelineResponse {
    posts: Post[]
    continuation?: string
}

export const fetchTimeline = (continuation?: string): AppThunkAction => async dispatch => {
    dispatch(startRequest(RequestKey.FetchTimeline))

    try {
        const response = await apiFetch<TimelineResponse>({
            path: `/v1/timeline?${objectToQuerystring({ continuation })}`,
        })

        const posts = normalize(response.posts, EntityType.Post)

        dispatch(setEntities(posts.entities))
        
        if (continuation) {
            dispatch(listAppend(EntityListKey.Timeline, posts.keys, response.continuation))
        } else {
            dispatch(listSet(EntityListKey.Timeline, posts.keys, response.continuation))
        }

        dispatch(finishRequest(RequestKey.FetchTimeline, true))
    } catch (err) {
        dispatch(finishRequest(RequestKey.FetchTimeline, false))
        throw err
    }
}

interface UserPostsResponse {
    user: User
    posts: Post[]
    continuation?: string
}

export const fetchUserPosts = (id: string, continuation?: string): AppThunkAction => async dispatch => {
    dispatch(startRequest(RequestKey.FetchUserPosts))

    try {
        const response = await apiFetch<UserPostsResponse>({
            path: `/v1/user/${id}/posts`,
        })

        const posts = normalize(response.posts.map(p => ({
            ...p,
            user: response.user,
        })), EntityType.Post)

        dispatch(setEntities(posts.entities))
        
        if (continuation) {
            dispatch(listAppend(`user:${id}:posts`, posts.keys, response.continuation))
        } else {
            dispatch(listSet(`user:${id}:posts`, posts.keys, response.continuation))
        }

        dispatch(finishRequest(RequestKey.FetchUserPosts, true))
    } catch (err) {
        dispatch(finishRequest(RequestKey.FetchUserPosts, false))
        throw err
    }
}