import { error, fail } from '@sveltejs/kit';
import { BACKEND_URL } from '$env/static/private';

const module = "book"

export async function getItems(project) {
    const response = await fetch(`${BACKEND_URL}/${project}/`);
    return response.json();
}

export async function getItem(project, id) {
    const response = await fetch(`${BACKEND_URL}/${project}/${id}`);
    if (response.status !== 200) throw error(response.status);
    const item = await response.json();
    return item;
}

export async function getEmptyItem(project) {
    const response = await fetch(`${BACKEND_URL}/_module/${project}`);
    if (response.status !== 200) throw error(response.status);
    const result = await response.json();
    const fields = Object.keys(result.fields);
    const entries = new Map(fields.map(field => [field, null]))
    return Object.fromEntries(entries);
}

export async function getProjects() {
    const response = await fetch(`${BACKEND_URL}/_module/`);
    if (response.status !== 200) throw error(response.status);
    return response.json();
}

export async function getProject(project) {
    const response = await fetch(`${BACKEND_URL}/_module/${project}`);
    if (response.status !== 200) throw error(response.status);
    return response.json();
}
    

export async function createItem(project, data) {
    const fields = Object.fromEntries(
        Array.from(data.entries()).filter(
            ([key, value]) => !(value instanceof File)
        )
    );

    const options = {
        method: 'POST',
        headers: {
            'Content-Type': 'application/json'
        },
        body: JSON.stringify(fields)
    }
    const response = await fetch(`${BACKEND_URL}/${project}/`, options);
    if (response.status !== 200) throw error(response.status);

    const item = await response.json();
    
    const files = Object.fromEntries(
        Array.from(data.entries()).filter(
            ([key, value]) => value instanceof File && value.size !== 0
        )
    );

    for (let key in files)
    {
        const data = new FormData()
        data.append('file', files[key]);
        await uploadFile(project, item["id"], key, data);
    }

    return item;
}

export async function updateItem(project, id, data) {
    const files = Object.fromEntries(
        Array.from(data.entries()).filter(
            ([key, value]) => value instanceof File && value.size !== 0
        )
    );

    for (let key in files)
    {
        const data = new FormData()
        data.append('file', files[key]);
        await deleteFile(project, id, key);
        await uploadFile(project, id, key, data);
    }

    const fields = Object.fromEntries(
        Array.from(data.entries()).filter(
            ([key, value]) => !(value instanceof File)
        )
    );

    const options = {
        method: 'PUT',
        headers: {
            'Content-Type': 'application/json'
        },
        body: JSON.stringify(fields)
    }
    const response = await fetch(`${BACKEND_URL}/${project}/${id}`, options);
    if (response.status !== 200) throw error(response.status);

    const item = response.json();
    return item;
}

export async function deleteItem(project, id) {
    const options = {
        method: 'DELETE',
        headers: {
            'Content-Type': 'application/json'
        },
    }
    const response = await fetch(`${BACKEND_URL}/${project}/${id}`, options);
    if (response.status !== 200) throw error(response.status);
    return response.json();
}

export async function readFile(project, id, field) {
    const response = await fetch(`${BACKEND_URL}/${project}/${id}/${field}`);
    return response;
}

export async function uploadFile(project, id, field, data) {
    const options = {
        method: 'POST',
        body: data,
    }
    const response = await fetch(`${BACKEND_URL}/${project}/${id}/${field}`, options);
    if (response.status !== 200) throw error(response.status);
    return response.json();
}

export async function deleteFile(project, id, field) {
    const options = {
        method: 'DELETE',
        headers: {
            'Content-Type': 'application/json'
        },
    }
    const response = await fetch(`${BACKEND_URL}/${project}/${id}/${field}`, options);
    if (response.status !== 200) throw error(response.status);
    return response.json();
}