// Copyright 2024, Command Line Inc.
// SPDX-License-Identifier: Apache-2.0

import { CodeEdit } from "@/app/view/codeedit";
import { PlotView } from "@/app/view/plotview";
import { PreviewView } from "@/app/view/preview";
import { TerminalView } from "@/app/view/term/term";
import { ErrorBoundary } from "@/element/errorboundary";
import { CenteredDiv } from "@/element/quickelems";
import { ContextMenuModel } from "@/store/contextmenu";
import { atoms, setBlockFocus, useBlockAtom } from "@/store/global";
import * as WOS from "@/store/wos";
import clsx from "clsx";
import * as jotai from "jotai";
import * as React from "react";

import "./block.less";

const HoverPixels = 15;
const HoverTimeoutMs = 100;

interface BlockProps {
    blockId: string;
    onClose?: () => void;
    dragHandleRef?: React.RefObject<HTMLDivElement>;
}

function getBlockHeaderText(blockData: Block): string {
    if (!blockData) {
        return "no block data";
    }
    return `${blockData?.view} [${blockData.oid.substring(0, 8)}]`;
}

interface FramelessBlockHeaderProps {
    blockId: string;
    onClose?: () => void;
    dragHandleRef?: React.RefObject<HTMLDivElement>;
}

const FramelessBlockHeader = ({ blockId, onClose, dragHandleRef }: FramelessBlockHeaderProps) => {
    const [blockData] = WOS.useWaveObjectValue<Block>(WOS.makeORef("block", blockId));

    return (
        <div key="header" className="block-header" ref={dragHandleRef}>
            <div className="block-header-text text-fixed">{getBlockHeaderText(blockData)}</div>
            {onClose && (
                <div className="close-button" onClick={onClose}>
                    <i className="fa fa-solid fa-xmark-large" />
                </div>
            )}
        </div>
    );
};

const hoverStateOff = "off";
const hoverStatePending = "pending";
const hoverStateOn = "on";

interface BlockFrameProps {
    blockId: string;
    onClose?: () => void;
    onClick?: () => void;
    preview: boolean;
    children?: React.ReactNode;
    blockRef?: React.RefObject<HTMLDivElement>;
    dragHandleRef?: React.RefObject<HTMLDivElement>;
}

const BlockFrame_Tech = ({
    blockId,
    onClose,
    onClick,
    preview,
    blockRef,
    dragHandleRef,
    children,
}: BlockFrameProps) => {
    const [blockData] = WOS.useWaveObjectValue<Block>(WOS.makeORef("block", blockId));
    const isFocusedAtom = useBlockAtom<boolean>(blockId, "isFocused", () => {
        return jotai.atom((get) => {
            const winData = get(atoms.waveWindow);
            return winData.activeblockid === blockId;
        });
    });
    let isFocused = jotai.useAtomValue(isFocusedAtom);
    if (preview) {
        isFocused = true;
    }
    function handleContextMenu(e: React.MouseEvent<HTMLDivElement>) {
        let menu: ContextMenuItem[] = [];
        menu.push({
            label: "Close",
            click: onClose,
        });
        ContextMenuModel.showContextMenu(menu, e);
    }
    return (
        <div
            className={clsx(
                "block",
                "block-frame-tech",
                isFocused ? "block-focused" : null,
                preview ? "block-preview" : null
            )}
            onClick={onClick}
            ref={blockRef}
        >
            <div className="block-frame-tech-header" ref={dragHandleRef} onContextMenu={handleContextMenu}>
                {getBlockHeaderText(blockData)}
            </div>
            <div className={clsx("block-frame-tech-close")} onClick={onClose}>
                <i className="fa fa-solid fa-xmark fa-fw" />
            </div>
            {preview ? <div className="block-frame-preview" /> : children}
        </div>
    );
};

const BlockFrame_Frameless = ({
    blockId,
    onClose,
    onClick,
    preview,
    blockRef,
    dragHandleRef,
    children,
}: BlockFrameProps) => {
    const localBlockRef = React.useRef<HTMLDivElement>(null);
    const [showHeader, setShowHeader] = React.useState(preview ? true : false);
    const hoverState = React.useRef(hoverStateOff);

    // this forward the lcal ref to the blockRef
    React.useImperativeHandle(blockRef, () => localBlockRef.current);

    React.useEffect(() => {
        if (preview) {
            return;
        }
        const block = localBlockRef.current;
        let hoverTimeout: NodeJS.Timeout = null;
        const handleMouseMove = (event) => {
            const rect = block.getBoundingClientRect();
            if (event.clientY - rect.top <= HoverPixels) {
                if (hoverState.current == hoverStateOff) {
                    hoverTimeout = setTimeout(() => {
                        if (hoverState.current == hoverStatePending) {
                            hoverState.current = hoverStateOn;
                            setShowHeader(true);
                        }
                    }, HoverTimeoutMs);
                    hoverState.current = hoverStatePending;
                }
            } else {
                if (hoverTimeout) {
                    if (hoverState.current == hoverStatePending) {
                        hoverState.current = hoverStateOff;
                    }
                    clearTimeout(hoverTimeout);
                    hoverTimeout = null;
                }
            }
        };
        block.addEventListener("mousemove", handleMouseMove);
        return () => {
            block.removeEventListener("mousemove", handleMouseMove);
        };
    });
    let mouseLeaveHandler = () => {
        if (preview) {
            return;
        }
        setShowHeader(false);
        hoverState.current = hoverStateOff;
    };
    return (
        <div
            className="block block-frame-frameless"
            ref={localBlockRef}
            onMouseLeave={mouseLeaveHandler}
            onClick={onClick}
        >
            <div
                className={clsx("block-header-animation-wrap", showHeader ? "is-showing" : null)}
                onMouseLeave={mouseLeaveHandler}
            >
                <FramelessBlockHeader blockId={blockId} onClose={onClose} dragHandleRef={dragHandleRef} />
            </div>
            {preview ? <div className="block-frame-preview" /> : children}
        </div>
    );
};

const BlockFrame = (props: BlockFrameProps) => {
    const blockId = props.blockId;
    const [blockData, blockDataLoading] = WOS.useWaveObjectValue<Block>(WOS.makeORef("block", blockId));
    const tabData = jotai.useAtomValue(atoms.tabAtom);

    if (!blockId || !blockData) {
        return null;
    }
    // if 0 or 1 blocks, use frameless, otherwise use tech
    const numBlocks = tabData?.blockids?.length ?? 0;
    if (numBlocks <= 1) {
        return <BlockFrame_Frameless {...props} />;
    }
    return <BlockFrame_Tech {...props} />;
};

const Block = ({ blockId, onClose, dragHandleRef }: BlockProps) => {
    let blockElem: JSX.Element = null;
    const focusElemRef = React.useRef<HTMLInputElement>(null);
    const blockRef = React.useRef<HTMLDivElement>(null);
    const [blockClicked, setBlockClicked] = React.useState(false);
    const [blockData, blockDataLoading] = WOS.useWaveObjectValue<Block>(WOS.makeORef("block", blockId));

    React.useLayoutEffect(() => {
        if (!blockClicked) {
            return;
        }
        setBlockClicked(false);
        const focusWithin = blockRef.current?.contains(document.activeElement);
        if (!focusWithin) {
            focusElemRef.current?.focus();
        }
        setBlockFocus(blockId);
    }, [blockClicked]);

    if (!blockId || !blockData) return null;
    if (blockDataLoading) {
        blockElem = <CenteredDiv>Loading...</CenteredDiv>;
    } else if (blockData.view === "term") {
        blockElem = <TerminalView blockId={blockId} />;
    } else if (blockData.view === "preview") {
        blockElem = <PreviewView blockId={blockId} />;
    } else if (blockData.view === "plot") {
        blockElem = <PlotView />;
    } else if (blockData.view === "codeedit") {
        blockElem = <CodeEdit text={null} filename={null} />;
    }
    return (
        <BlockFrame
            blockId={blockId}
            onClose={onClose}
            preview={false}
            onClick={() => setBlockClicked(true)}
            blockRef={blockRef}
            dragHandleRef={dragHandleRef}
        >
            <div key="focuselem" className="block-focuselem">
                <input type="text" value="" ref={focusElemRef} onChange={() => {}} />
            </div>
            <div key="content" className="block-content">
                <ErrorBoundary>
                    <React.Suspense fallback={<CenteredDiv>Loading...</CenteredDiv>}>{blockElem}</React.Suspense>
                </ErrorBoundary>
            </div>
        </BlockFrame>
    );
};

export { Block, BlockFrame };