/*
 * Copyright 2024 Palantir Technologies, Inc. All rights reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import classNames from "classnames";
import { createElement, forwardRef, useMemo } from "react";

import { type IconName, IconNames } from "@blueprintjs/icons";

import { Classes, DISPLAYNAME_PREFIX, type MaybeElement, type Props } from "../../common";
import { H1, H2, H3, H4, H5, H6 } from "../html/html";
import { Icon } from "../icon/icon";
import { Text, type TextProps } from "../text/text";

export interface EntityTitleProps extends Props {
    /**
     * Whether the overflowing text content should be ellipsized.
     *
     * @default false
     */
    ellipsize?: boolean;

    /** Whether the component should expand to fill its container. */
    fill?: boolean;

    /**
     * React component to render the main title heading. This defaults to
     * Blueprint's `<Text>` component, * which inherits font size from its
     * containing element(s).
     *
     * To render larger, more prominent titles, Use Blueprint's heading
     * components instead (e.g. `{ H1 } from "@blueprintjs/core"`).
     *
     * @default Text
     */
    heading?: React.FC<any>;

    /**
     * Name of a Blueprint UI icon (or an icon element) to render in the section's header.
     * Note that the header will only be rendered if `title` is provided.
     */
    icon?: IconName | MaybeElement;

    /**
     * Whether to render as loading state.
     *
     * @default false
     */
    loading?: boolean;

    /** The content to render below the title. Defaults to render muted text. */
    subtitle?: React.JSX.Element | string;

    /** The primary title to render. */
    title: React.JSX.Element | string;

    /** If specified, the title will be wrapped in an anchor with this URL. */
    titleURL?: string;

    /**
     * <Tag> components work best - if multiple, wrap in <React.Fragment>
     */
    tags?: React.ReactNode;
}

/**
 * EntityTitle component.
 *
 * @see https://blueprintjs.com/docs/#core/components/entity-title
 */
export const EntityTitle: React.FC<EntityTitleProps> = forwardRef<HTMLDivElement, EntityTitleProps>((props, ref) => {
    const {
        className,
        ellipsize = false,
        fill = false,
        heading = Text,
        icon,
        loading = false,
        subtitle,
        tags,
        title,
        titleURL,
    } = props;

    const titleElement = useMemo(() => {
        const maybeTitleWithURL =
            titleURL != null ? (
                <a target="_blank" href={titleURL} rel="noreferrer">
                    {title}
                </a>
            ) : (
                title
            );

        return createElement(
            heading,
            {
                className: classNames(Classes.ENTITY_TITLE_TITLE, {
                    [Classes.SKELETON]: loading,
                    [Classes.TEXT_OVERFLOW_ELLIPSIS]: heading !== Text && ellipsize,
                }),
                ellipsize: heading === Text ? ellipsize : undefined,
            },
            maybeTitleWithURL,
        );
    }, [titleURL, title, heading, loading, ellipsize]);

    const maybeSubtitle = useMemo(() => {
        if (subtitle == null) {
            return null;
        }

        return (
            <Text
                className={classNames(Classes.TEXT_MUTED, Classes.ENTITY_TITLE_SUBTITLE, {
                    [Classes.SKELETON]: loading,
                })}
                ellipsize={ellipsize}
            >
                {subtitle}
            </Text>
        );
    }, [ellipsize, loading, subtitle]);

    return (
        <div
            className={classNames(className, Classes.ENTITY_TITLE, getClassNameFromHeading(heading), {
                [Classes.ENTITY_TITLE_ELLIPSIZE]: ellipsize,
                [Classes.FILL]: fill,
            })}
            ref={ref}
        >
            {icon != null && (
                <div
                    className={classNames(Classes.ENTITY_TITLE_ICON_CONTAINER, {
                        [Classes.ENTITY_TITLE_HAS_SUBTITLE]: maybeSubtitle != null,
                    })}
                >
                    <Icon
                        aria-hidden={true}
                        className={classNames(Classes.TEXT_MUTED, { [Classes.SKELETON]: loading })}
                        icon={loading ? IconNames.SQUARE : icon}
                        tabIndex={-1}
                    />
                </div>
            )}
            <div className={Classes.ENTITY_TITLE_TEXT}>
                <div
                    className={classNames(Classes.ENTITY_TITLE_TITLE_AND_TAGS, {
                        [Classes.SKELETON]: loading,
                    })}
                >
                    {titleElement}
                    {tags != null && <div className={Classes.ENTITY_TITLE_TAGS_CONTAINER}>{tags}</div>}
                </div>
                {maybeSubtitle}
            </div>
        </div>
    );
});
EntityTitle.displayName = `${DISPLAYNAME_PREFIX}.EntityTitle`;

/**
 * Construct header class name from H{*}. Returns `undefined` if `heading` is not a Blueprint heading.
 */
function getClassNameFromHeading(heading: React.FC<TextProps>) {
    const headerIndex = [H1, H2, H3, H4, H5, H6].findIndex(header => header === heading);
    if (headerIndex < 0) {
        return undefined;
    }
    return [Classes.getClassNamespace(), "entity-title-heading", `h${headerIndex + 1}`].join("-");
}