import { DOMSerializer, Slice } from "prosemirror-model"
import { EditorView } from "prosemirror-view";

export function serializeForClipboard(view: EditorView, slice: Slice) {
    view.someProp("transformCopied", f => {
        slice = f(slice!, view)
    })

    const context = [];
    let {
        content,
        openStart,
        openEnd
    } = slice
    while (openStart > 1 && openEnd > 1 && content.childCount == 1 && content.firstChild!.childCount == 1) {
        openStart--
        openEnd--
        const node = content.firstChild!
        // @ts-ignore
        context.push(node.type.name, node.attrs != node.type.defaultAttrs ? node.attrs : null)
        content = node.content
    }

    const serializer = view.someProp("clipboardSerializer") || DOMSerializer.fromSchema(view.state.schema)
    const doc = detachedDoc(), wrap = doc.createElement("div")
    wrap.appendChild(serializer.serializeFragment(content, { document: doc }))

    let firstChild = wrap.firstChild, needsWrap, wrappers = 0
    while (firstChild && firstChild.nodeType == 1 && (needsWrap = wrapMap[firstChild.nodeName.toLowerCase()])) {
        for (let i = needsWrap.length - 1; i >= 0; i--) {
            const wrapper = doc.createElement(needsWrap[i])
            while (wrap.firstChild) wrapper.appendChild(wrap.firstChild)
            wrap.appendChild(wrapper)
            wrappers++
        }
        firstChild = wrap.firstChild
    }

    if (firstChild && firstChild.nodeType == 1)
        (firstChild as HTMLElement).setAttribute(
            "data-pm-slice", `${openStart} ${openEnd}${wrappers ? ` -${wrappers}` : ""} ${JSON.stringify(context)}`)

    const text = view.someProp("clipboardTextSerializer", f => f(slice, view)) ||
        slice.content.textBetween(0, slice.content.size, "\n\n")

    return {
        dom: wrap,
        text,
        slice
    }
}

// Trick from jQuery -- some elements must be wrapped in other
// elements for innerHTML to work. I.e. if you do `div.innerHTML =
// "<td>..</td>"` the table cells are ignored.
const wrapMap: { [node: string]: string[] } = {
    thead: ["table"],
    tbody: ["table"],
    tfoot: ["table"],
    caption: ["table"],
    colgroup: ["table"],
    col: ["table", "colgroup"],
    tr: ["table", "tbody"],
    td: ["table", "tbody", "tr"],
    th: ["table", "tbody", "tr"]
}

let _detachedDoc: Document | null = null

function detachedDoc() {
    return _detachedDoc || (_detachedDoc = document.implementation.createHTMLDocument("title"))
}