/* Copyright: Ankitects Pty Ltd and contributors
 * License: GNU AGPL, version 3 or later; http://www.gnu.org/licenses/agpl.html */

import { EditingArea } from ".";
import { nodeIsElement } from "./helpers";
import { triggerChangeTimer } from "./changeTimer";

function inListItem(currentField: EditingArea): boolean {
    const anchor = currentField.getSelection()!.anchorNode!;

    let inList = false;
    let n = nodeIsElement(anchor) ? anchor : anchor.parentElement;
    while (n) {
        inList = inList || window.getComputedStyle(n).display == "list-item";
        n = n.parentElement;
    }

    return inList;
}

export function onInput(event: Event): void {
    // make sure IME changes get saved
    triggerChangeTimer(event.currentTarget as EditingArea);
}

export function onKey(evt: KeyboardEvent): void {
    const currentField = evt.currentTarget as EditingArea;

    // esc clears focus, allowing dialog to close
    if (evt.code === "Escape") {
        currentField.blurEditable();
        return;
    }

    // prefer <br> instead of <div></div>
    if (evt.code === "Enter" && !inListItem(currentField)) {
        evt.preventDefault();
        document.execCommand("insertLineBreak");
    }

    // // fix Ctrl+right/left handling in RTL fields
    if (currentField.isRightToLeft()) {
        const selection = currentField.getSelection();
        const granularity = evt.ctrlKey ? "word" : "character";
        const alter = evt.shiftKey ? "extend" : "move";

        switch (evt.code) {
            case "ArrowRight":
                selection.modify(alter, "right", granularity);
                evt.preventDefault();
                return;
            case "ArrowLeft":
                selection.modify(alter, "left", granularity);
                evt.preventDefault();
                return;
        }
    }

    triggerChangeTimer(currentField);
}

export function onKeyUp(evt: KeyboardEvent): void {
    const currentField = evt.currentTarget as EditingArea;

    // Avoid div element on remove
    if (evt.code === "Enter" || evt.code === "Backspace") {
        const anchor = currentField.getSelection().anchorNode as Node;

        if (
            nodeIsElement(anchor) &&
            anchor.tagName === "DIV" &&
            !(anchor instanceof EditingArea) &&
            anchor.childElementCount === 1 &&
            anchor.children[0].tagName === "BR"
        ) {
            anchor.replaceWith(anchor.children[0]);
        }
    }
}