import type { Task } from 'fhir/r4';

/**
 * The completed task as it is sent, carrying the patient's optional message.
 *
 * The message goes as a note with no time or author: the server stamps both, and takes only the text
 * of that one note, so the notes already on the task cannot be rewritten from here.
 */
export const completedWithMessage = (task: Task, message?: string): Task => {
    const text = message?.trim();

    return {
        ...task,
        status: 'completed',
        ...(text ? { note: [...(task.note ?? []), { text }] } : {}),
    };
};

const isPatientSide = (reference: string | undefined): boolean =>
    !!reference && (reference.startsWith('Patient/') || reference.startsWith('RelatedPerson/'));

/** What the patient wrote when they marked the task complete, if they wrote anything. */
export const patientCompletionMessage = (task: Task): string | undefined => {
    if (task.status !== 'completed') {
        return undefined;
    }

    const notes = task.note ?? [];

    for (let index = notes.length - 1; index >= 0; index -= 1) {
        const note = notes[index];

        if (isPatientSide(note.authorReference?.reference) && note.text?.trim()) {
            return note.text.trim();
        }
    }

    return undefined;
};