/**
 * Dailymotion Pro – Admin Video Embed: state toggles
 *
 * Enables/disables controls based on checkbox states and the global contextual toggle.
 */

import { getFormState, qs } from '../../Libs/Utils';

let initialFormStates = new Map<HTMLFormElement, string>();

/**
 * Initializes the form state tracking.
 */
export function initFormState(form: HTMLFormElement): void {
    initialFormStates.set(form, getFormState(form));
    updateSubmitButtonState(form);
}

/**
 * Resets the stored initial state to the form's current state.
 * Use after an action that changes the form (e.g. disabling contextual) so
 * beforeunload no longer treats the form as dirty.
 */
export function resetFormState(form: HTMLFormElement): void {
    initialFormStates.set(form, getFormState(form));
    updateSubmitButtonState(form);
}

const TOGGLE_FIELD = 'contextual_embed';

/**
 * Returns true when the only difference between initial and current is
 * contextual_embed going from on (truthy) to off (falsy).
 */
function isOnlyToggleOnToOff(initialJson: string, currentJson: string): boolean {
    try {
        const initial = JSON.parse(initialJson) as Record<string, unknown>;
        const current = JSON.parse(currentJson) as Record<string, unknown>;
        if (!(TOGGLE_FIELD in initial) && !(TOGGLE_FIELD in current)) return false;
        const initialToggle = initial[TOGGLE_FIELD];
        const currentToggle = current[TOGGLE_FIELD];
        const wasOn = initialToggle !== undefined && initialToggle !== '' && initialToggle !== null;
        const isOff = currentToggle === undefined || currentToggle === '' || currentToggle === null;
        if (!wasOn || !isOff) return false;
        delete initial[TOGGLE_FIELD];
        delete current[TOGGLE_FIELD];
        return JSON.stringify(initial) === JSON.stringify(current);
    } catch {
        return false;
    }
}

/**
 * Checks if a form has changes compared to its initial state.
 * Exception: not dirty when the only change is contextual_embed toggling from on to off.
 */
export function isFormDirty(form: HTMLFormElement): boolean {
    const initialState = initialFormStates.get(form);
    if (initialState === undefined) return false;
    const current = getFormState(form);
    if (initialState === current) return false;
    if (isOnlyToggleOnToOff(initialState, current)) return false;
    return true;
}

/**
 * Updates the disabled state of the submit button based on form changes.
 */
export function updateSubmitButtonState(form: HTMLFormElement): void {
    const saveBtn = form.querySelector('button[type="submit"]') as HTMLButtonElement | null;
    if (!saveBtn) return;
    saveBtn.disabled = !isFormDirty(form);
}