// removeParticipant + computeTurnOrderAfterRemoval edge cases.

const shared = require('@ttrpg/shared');
const { makeParticipant, startEncounter, nextTurn, removeParticipant, toggleParticipantActive, applyHpChange } = shared;

function p(id, init, extra = {}) {
  return makeParticipant({ id, name: id, type: 'monster',
    initiative: init, maxHp: 100, currentHp: 100, ...extra });
}
function enc(ps) {
  return { name:'t', participants:ps, isStarted:false, isPaused:false,
    round:0, currentTurnParticipantId:null, turnOrderIds:[] };
}

describe('removeParticipant turn-order edges', () => {
  test('removing current picks next active as current', () => {
    let e = enc([p('a',20),p('b',15),p('c',10)]);
    e = { ...e, ...startEncounter(e).patch };
    e = { ...e, ...removeParticipant(e, 'a').patch }; // a was current
    expect(e.currentTurnParticipantId).toBe('b');
  });

  test('removing last in order wraps current to first', () => {
    let e = enc([p('a',20),p('b',15),p('c',10)]);
    e = { ...e, ...startEncounter(e).patch };
    e = { ...e, ...nextTurn(e).patch }; // b
    e = { ...e, ...nextTurn(e).patch }; // c (current)
    e = { ...e, ...removeParticipant(e, 'c').patch };
    expect(e.currentTurnParticipantId).toBe('a');
  });

  test('removing current when all others inactive → no active, isStarted stays (BUG-9 candidate)', () => {
    let e = enc([p('a',20),p('b',15),p('c',10)]);
    e = { ...e, ...startEncounter(e).patch }; // [a,b,c], cur=a
    // deactivate b + c (stay in slot, inactive)
    e = { ...e, ...toggleParticipantActive(e, 'b').patch };
    e = { ...e, ...toggleParticipantActive(e, 'c').patch };
    // remove current a
    e = { ...e, ...removeParticipant(e, 'a').patch };
    // 1-list: turnOrderIds=[b,c], no active → current null, isStarted stays true
    expect(e.turnOrderIds).toEqual(['b', 'c']);
    expect(e.currentTurnParticipantId).toBeNull();
    // isStarted still true but no turn → nextTurn throws (stale state)
  });

  test('removing non-current keeps currentTurn', () => {
    let e = enc([p('a',20),p('b',15),p('c',10)]);
    e = { ...e, ...startEncounter(e).patch };
    e = { ...e, ...removeParticipant(e, 'b').patch };
    expect(e.currentTurnParticipantId).toBe('a');
    expect(e.turnOrderIds).toEqual(['a', 'c']);
  });

  test('removing current that is dead (HP=0) - BUG-3 overlap', () => {
    // Dead participant removed mid-combat. Desired (M4): they STAY in order.
    // removeParticipant is explicit DM action, distinct from auto-skip.
    let e = enc([p('a',20),p('b',15),p('c',10)]);
    e = { ...e, ...startEncounter(e).patch };
    e = { ...e, ...applyHpChange(e, 'b', 'damage', 100).patch }; // b dead
    e = { ...e, ...removeParticipant(e, 'b').patch };
    expect(e.turnOrderIds).not.toContain('b');
    expect(e.participants.find(x => x.id === 'b')).toBeUndefined();
  });
});
