// The rules the Automated Tasks page applies, kept pure so they can be tested without the page.
import type { Extension, Questionnaire } from 'fhir/r4';
import { AUTO_ASSIGN_TRIGGER_URL, type AutoAssignTrigger } from '../../../config/autoAssign';

// Both ActivityDefinition and Questionnaire carry the trigger as one extension. Forms settings reads and
// writes the same one, so a change here shows there.
export const getTrigger = (resource: { extension?: Extension[] }): AutoAssignTrigger => {
    const code = resource.extension?.find((ext) => ext.url === AUTO_ASSIGN_TRIGGER_URL)?.valueCode;
    return code === 'all-appointments' || code === 'new-patient-appointments' ? code : 'off';
};

/** The line under the trigger choice, in the deck words. */
export const triggerHelp = (trigger: AutoAssignTrigger | ''): string => {
    switch (trigger) {
        case 'all-appointments': return 'Assigned when any appointment is booked.';
        case 'new-patient-appointments': return 'Assigned when a new patient appointment is booked.';
        case 'off': return 'Off keeps the task saved without assigning it automatically.';
        default: return 'Choose when this questionnaire should be assigned. Nothing is selected automatically.';
    }
};

/** The Assigned when column of a row. Off stays visible rather than hiding the task. */
export const assignedWhen = (trigger: AutoAssignTrigger): string => {
    switch (trigger) {
        case 'all-appointments': return 'Any appointment is booked';
        case 'new-patient-appointments': return 'New patient appointment is booked';
        default: return 'Off';
    }
};

export type QuestionnaireEligibility = 'eligible' | 'draft' | 'public' | 'assigned' | 'unchecked';

/**
 * Only an active clinical questionnaire with no rule may become an automated task, and none while
 * the public forms are unread, so a public form cannot slip through.
 */
export const questionnaireEligibility = (
    questionnaire: Questionnaire,
    publicQuestionnaireIds: ReadonlySet<string> | null,
): QuestionnaireEligibility => {
    if (publicQuestionnaireIds === null) return 'unchecked';
    if (questionnaire.id && publicQuestionnaireIds.has(questionnaire.id)) return 'public';
    if (getTrigger(questionnaire) !== 'off') return 'assigned';
    if (questionnaire.status !== 'active') return 'draft';
    return 'eligible';
};