import { ObjectField } from "./ObjectField";
import { serializable } from "serializr";
import { Deserializable } from "../client/util/SerializationHelper";
import { Copy, ToScriptString } from "./FieldSymbols";
import { scriptingGlobal } from "../client/util/Scripting";

export const ToGoogleDocText = Symbol("PlainText");
export const FromGoogleDocText = Symbol("PlainText");
const delimiter = "\n";
const joiner = "";

@scriptingGlobal
@Deserializable("RichTextField")
export class RichTextField extends ObjectField {
    @serializable(true)
    readonly Data: string;

    constructor(data: string) {
        super();
        this.Data = data;
    }

    [Copy]() {
        return new RichTextField(this.Data);
    }

    [ToScriptString]() {
        return `new RichTextField("${this.Data}")`;
    }

    [ToGoogleDocText]() {
        // Because we're working with plain text, just concatenate all paragraphs
        let content = JSON.parse(this.Data).doc.content;
        let paragraphs = content.filter((item: any) => item.type === "paragraph");

        // Functions to flatten ProseMirror paragraph objects (and their components) to plain text
        // While this function already exists in state.doc.textBeteen(), it doesn't account for newlines 
        let blockText = (block: any) => block.text;
        let concatenateParagraph = (p: any) => (p.content ? p.content.map(blockText).join(joiner) : "") + delimiter;

        // Concatentate paragraphs and string the result together. Trim the last newline, an artifact.
        let textParagraphs = paragraphs.map(concatenateParagraph);
        return textParagraphs.join(joiner).trimEnd(delimiter);
    }

    [FromGoogleDocText](plainText: string) {
        // Remap the text, creating blocks split on newlines
        let elements = plainText.split(delimiter);

        // Google Docs adds in an extra carriage return automatically, so this counteracts it
        !elements[elements.length - 1].length && elements.pop();

        // Preserve the current state, but re-write the content to be the blocks
        let parsed = JSON.parse(this.Data);
        parsed.doc.content = elements.map(text => {
            let paragraph: any = { type: "paragraph" };
            text.length && (paragraph.content = [{ type: "text", marks: [], text }]); // An empty paragraph gets treated as a line break
            return paragraph;
        });

        // If the new content is shorter than the previous content and selection is unchanged, may throw an out of bounds exception, so we reset it
        parsed.selection = { type: "text", anchor: 1, head: 1 };

        // Export the ProseMirror-compatible state object we've jsut built
        return JSON.stringify(parsed);
    }

}