const prefix = ""


async function unknownResponse(resp: Response): Promise<Error> {
    let json = await resp.json()
    try {
        return new Error(`${json["message"]} (${resp.status})`)
    } catch (error) {
        return new Error(`Server sent unknown error: ${await resp.text()} (${resp.status})`)
    }
}

function buildQuery(options: any[][]): string {
    let query: string[]
    options.forEach(element => {
        if (element[1] !== undefined) {
            if (element[1] instanceof Date) {
                element[1] = element[1].getSeconds()
            } else if (element[1] instanceof Array) {
                element[1] = JSON.stringify(element[1])
            }
            query.push(`${element[0]}&${element[1]}`)
        }
    });
    return query.join("=")
}

interface Author {
    id: number,
    name: string,
    information: string
}

interface ArticleSummary {
    id: number,
    title: string,
    summary: string
    authors: Author[],
    image?: string,
    tags: string[],
    created: Date,
    modified?: Date,
    link: string
}

interface Asset {
    id: number,
    name: string,
    link: string
}

async function login(username: string, password: string): Promise<void> {
    let result = await fetch(`${prefix}/api/login`, {
        method: "POST",
        body: JSON.stringify({"username": username, "password": password})
    })
    switch (result.status) {
        case 200:
            return
        case 401:
            throw new Error("Wrong username and/or password")
        default:
            throw await unknownResponse(result)
    }
}

async function authors(name?: string, limit?: number): Promise<Author[]> {
    let query = [["name", name], ["limit", limit]]

    let result = await fetch(`${prefix}/api/authors?${buildQuery(query)}`)
    if (result.status == 200) {
        return await result.json()
    } else {
        throw await unknownResponse(result)
    }
}

async function tags(name?: string, limit?: number): Promise<string[]> {
    let query = [["name", name], ["limit", limit]]

    let result = await fetch(`${prefix}/api/tags?${buildQuery(query)}`)
    if (result.status == 200) {
        return await result.json()
    } else {
        throw await unknownResponse(result)
    }
}

async function recent(limit: number = 20): Promise<ArticleSummary[]> {
    let query = [["limit", limit]]

    let result = await fetch(`${prefix}/api/recent?limit=${buildQuery(query)}`)
    if (result.status == 200) {
        return await result.json()
    } else {
        throw await unknownResponse(result)
    }
}

interface SearchQuery {
    query?: string,
    from?: Date,
    to?: Date,
    authors?: number[],
    tags?: string[],
    limit?: number
}

async function search(q: SearchQuery): Promise<ArticleSummary[]> {
    let query = [["q", q.query], ["from", q.from], ["to", q.to], ["authors", q.authors], ["tags", q.tags], ["limit", q.limit]]

    let result = await fetch(`${prefix}/api/search?${buildQuery(query)}`)
    if (result.status == 200) {
        return await result.json()
    } else {
        throw unknownResponse(result)
    }
}

interface ArticleUploadPayload {
    title: string,
    summary: string,
    authors: number[],
    image?: string,
    tags: string[],
    link?: string
    content: string
}

async function uploadArticle(payload: ArticleUploadPayload): Promise<ArticleSummary> {
    let result = await fetch(`${prefix}/api/article`, {
        method: "POST",
        body: JSON.stringify(payload)
    })
    switch (result.status) {
        case 201:
            return await result.json()
        case 401:
            throw new Error("Not authorized")
        case 409:
            throw new Error("An article with the same title already exists")
        default:
            throw await unknownResponse(result)
    }
}

interface ArticleEditPayload {
    id: number,
    title?: string,
    summary?: string,
    authors?: number[],
    image?: string,
    tags?: string[],
    link?: string
    content?: string
}

async function editArticle(payload: ArticleEditPayload): Promise<ArticleSummary> {
    let result = await fetch(`${prefix}/api/article`, {
        method: "PATCH",
        body: JSON.stringify(payload)
    })
    let json = await result.json()

    switch (result.status) {
        case 201:
            return json
        case 401:
            throw new Error("Not authorized")
        case 404:
            throw new Error("Could not find article")
        case 409:
            throw new Error("An article with the same title already exists")
        default:
            throw await unknownResponse(result)
    }
}

async function deleteArticle(id: number): Promise<void> {
    let result = await fetch(`${prefix}/api/article`, {
        method: "DELETE",
        body: JSON.stringify({"id": id})
    })
    switch (result.status) {
        case 200:
            return
        case 401:
            throw new Error("Not authorized")
        case 404:
            throw new Error("Could not find article")
        default:
            throw await unknownResponse(result)
    }
}

async function getAssets(name?: string, limit: number = 20): Promise<Asset[]> {
    let query = [["q", name], ["limit", limit]]

    let result = await fetch(`${prefix}/api/assets?${buildQuery(query)}`, {
        method: "GET",
    })
    switch (result.status) {
        case 200:
            return await result.json()
        case 401:
            throw new Error("Not authorized")
        default:
            throw await unknownResponse(result)
    }
}

async function addAsset(name: string, content: string): Promise<Asset> {
    let result = await fetch(`${prefix}/api/assets`, {
        method: "POST",
        body: JSON.stringify({
            "name": name,
            "content": content,
        })
    })
    switch (result.status) {
        case 201:
            return await result.json()
        case 401:
            throw new Error("Not authorized")
        case 409:
            throw new Error("An asset with the same name already exists")
        default:
            throw await unknownResponse(result)
    }
}

async function deleteAsset(id: number): Promise<void> {
    let result = await fetch(`${prefix}/api/assets`, {
        method: "DELETE",
        body: JSON.stringify({"id": id})
    })
    switch (result.status) {
        case 200:
            return
        case 401:
            throw new Error("Not authorized")
        case 404:
            throw new Error("An asset with this id does not exist")
        default:
            throw await unknownResponse(result)
    }
}