import classNames from "classnames";
import * as React from "react";
import * as Classes from "../../common/classes";
import { Elevation } from "../../common/elevation";
import { DISPLAYNAME_PREFIX, HTMLDivProps, IProps } from "../../common/props";

export interface IPanelProps extends IProps, HTMLDivProps {
    /**
     * Controls the intensity of the drop shadow beneath the panel: the higher
     * the elevation, the higher the drop shadow. At elevation `0`, no drop
     * shadow is applied.
     *
     * @default 0
     */
    elevation?: Elevation;

    /**
     * Whether the panel should respond to user interactions. If set to `true`,
     * hovering over the panel will increase the panel's elevation
     * and change the mouse cursor to a pointer.
     *
     * Recommended when `onClick` is also defined.
     *
     * @default false
     */
    interactive?: boolean;

    /**
     * Header props
     */
    headerProps?: IProps & HTMLDivProps;

    /**
     * Header element
     */
    header?: React.ReactNode;

    /**
     * Callback invoked when the panel is clicked.
     * Recommended when `interactive` is `true`.
     */
    onClick?: (e: React.MouseEvent<HTMLDivElement>) => void;
}

export class Panel extends React.PureComponent<IPanelProps, {}> {
    public static displayName = `${DISPLAYNAME_PREFIX}.Panel`;
    public static defaultProps: IPanelProps = {
        elevation: Elevation.ZERO,
        interactive: false,
    };

    public render() {
        const { className, elevation, interactive, children, header, headerProps, ...htmlProps } = this.props;
        const { className: headerClassName, ...htmHeaderProps } = headerProps || {
            className: null
        };
        
        const classes = classNames(
            Classes.PANEL,
            { [Classes.INTERACTIVE]: interactive },
            Classes.elevationClass(elevation),
            className,
        );

        const classesHeader = classNames(
            Classes.PANEL_HEADER,
            headerClassName,
        );

        return (
            <div className={classes} {...htmlProps}>
                {header && <div className={classesHeader} {...htmHeaderProps}>{header}</div>}
                {children}
            </div>
        );
    }
}
