import { describe, expect, test } from 'bun:test';
import { setProperty } from './useDavEdit';
import { parseEvents } from '../../sidecar/ical';

// setProperty is the whole editing story: it decides what an edit keeps and what it destroys. These
// cover the two ways it can quietly destroy something — dropping a property's parameters, and leaving
// half of a folded value behind.

const ICS = [
  'BEGIN:VCALENDAR',
  'VERSION:2.0',
  'BEGIN:VEVENT',
  'UID:abc',
  'DTSTAMP:20260827T100000Z',
  'DTSTART;TZID=Europe/Lisbon:20260828T130000',
  'DTEND;TZID=Europe/Lisbon:20260828T140000',
  'SUMMARY:Before',
  'RRULE:FREQ=WEEKLY',
  'BEGIN:VALARM',
  'ACTION:DISPLAY',
  'TRIGGER:-PT15M',
  'END:VALARM',
  'END:VEVENT',
  'END:VCALENDAR',
].join('\r\n');

describe('setProperty', () => {
  test('changes only the line it owns', () => {
    const out = setProperty(ICS, 'SUMMARY', 'After');
    expect(out.split('\r\n').length).toBe(ICS.split('\r\n').length);
    expect(out).toContain('SUMMARY:After');
    expect(out).toContain('RRULE:FREQ=WEEKLY');
    expect(out).toContain('BEGIN:VALARM');
  });

  test('keeps a property that carries parameters', () => {
    const out = setProperty(ICS, 'DTSTART', '20260901T090000');
    expect(out).toContain('DTSTART;TZID=Europe/Lisbon:20260901T090000');
  });

  test('appends after UID when the property is absent, so it lands in the right component', () => {
    const out = setProperty(ICS, 'LOCATION', 'Ramiro');
    const lines = out.split('\r\n');
    expect(lines[lines.indexOf('UID:abc') + 1]).toBe('LOCATION:Ramiro');
  });

  test('null removes the property', () => {
    expect(setProperty(ICS, 'RRULE', null)).not.toContain('RRULE');
  });

  test('escapes the TEXT separators', () => {
    const out = setProperty(ICS, 'SUMMARY', 'a, b; c');
    expect(out).toContain(String.raw`SUMMARY:a\, b\; c`);
    expect(parseEvents(out)[0]!.summary).toBe('a, b; c');
  });

  // The regression. A folded property spans several lines; replacing only the first left the rest
  // behind, and they folded onto the NEW value — so each edit silently inherited the tail of the last.
  test('replaces the whole of a folded value, continuations included', () => {
    const folded = ICS.replace('SUMMARY:Before', 'SUMMARY:Before, and then quite a lot more text that\r\n  was folded onto a second line');
    const out = setProperty(folded, 'SUMMARY', 'After');
    expect(parseEvents(out)[0]!.summary).toBe('After');
    expect(out).not.toContain('folded onto a second line');
  });

  test('removing a folded property takes all of it', () => {
    const folded = ICS.replace('RRULE:FREQ=WEEKLY', 'RRULE:FREQ=WEEKLY\r\n ;COUNT=10');
    expect(setProperty(folded, 'RRULE', null)).not.toContain('COUNT=10');
  });

  test('a long new value is folded, and reads back whole', () => {
    const long = 'y'.repeat(300);
    const out = setProperty(ICS, 'SUMMARY', long);
    expect(out.split('\r\n').every((l) => Buffer.byteLength(l, 'utf8') <= 75)).toBe(true);
    expect(parseEvents(out)[0]!.summary).toBe(long);
  });

  test('repeated edits do not accumulate', () => {
    let out = ICS;
    for (const v of ['one'.repeat(40), 'two'.repeat(40), 'three']) out = setProperty(out, 'SUMMARY', v);
    expect(parseEvents(out)[0]!.summary).toBe('three');
  });
});