// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this
// file, You can obtain one at https://mozilla.org/MPL/2.0/.

(() => {
    const darkThemes = ['ayu', 'navy', 'coal'];
    const lightThemes = ['light', 'rust'];

    const classList = document.getElementsByTagName('html')[0].classList;

    let lastThemeWasLight = true;
    for (const cssClass of classList) {
        if (darkThemes.includes(cssClass)) {
            lastThemeWasLight = false;
            break;
        }
    }

    const theme = lastThemeWasLight ? 'default' : 'dark';
    mermaid.initialize({ startOnLoad: false, theme });

    // Simplest way to make mermaid re-render the diagrams in the new theme is via refreshing the page

    function initThemeButtons() {
        for (const darkTheme of darkThemes) {
            const darkBtn = document.getElementById(darkTheme);
            if (darkBtn) {
                darkBtn.addEventListener('click', () => {
                    if (lastThemeWasLight) {
                        window.location.reload();
                    }
                });
            }
        }

        for (const lightTheme of lightThemes) {
            const lightBtn = document.getElementById(lightTheme);
            if (lightBtn) {
                lightBtn.addEventListener('click', () => {
                    if (!lastThemeWasLight) {
                        window.location.reload();
                    }
                });
            }
        }
    }

    if (document.readyState === 'loading') {
        document.addEventListener('DOMContentLoaded', initThemeButtons);
    } else {
        initThemeButtons();
    }
})();