/**
 * The game session host (`src/server/session.ts`) — pure logic, no sockets, exercised directly.
 */

import { describe, it } from 'node:test';
import assert from 'node:assert/strict';

import type { GameConfig, PlayerIndex } from '../../src/engine/state.ts';
import type { GameSession, Push } from '../../src/server/session.ts';
import { createSession, resumeSession, tryResumeSession } from '../../src/server/session.ts';

const config: GameConfig = {
  mode: 'competitive',
  days: 5,
  minCombinedRevenue: 0,
  maxCollisionsPerDay: 0,
  maxCollisionsTotal: 0,
  pvpCardsAllowed: false,
  optionalRules: {
    reducedVisibility: false,
    employeeRotation: false,
    emergencyToolbox: false,
  },
};

describe('the game session host', () => {
  it('gives a fresh connect a full Frame — nothing nulled', () => {
    const session = createSession(42, config, ['Alice', 'Bob']);
    const push = session.connect(0 as PlayerIndex);
    assert.notEqual(push.frame!.cells, null, 'a first connect nulled the board');
    assert.notEqual(push.frame!.division, null, 'a first connect nulled the division');
  });

  it('only the current actor gets a real Menu; every other seat gets null', () => {
    const session = createSession(42, config, ['Alice', 'Bob']);
    const a = session.connect(0 as PlayerIndex);
    const b = session.connect(1 as PlayerIndex);
    const actorPushes = [a, b].filter((p) => p.menu !== null);
    assert.equal(actorPushes.length, 1, 'more than one seat (or zero) was given a real Menu');
  });

  it('rejects an intent from a seat that is not the current actor, with NOT_YOUR_TURN', () => {
    const session = createSession(42, config, ['Alice', 'Bob']);
    // Whichever seat is NOT the current actor should be refused, regardless of the intent's content.
    const bPush = session.connect(1 as PlayerIndex);
    const notActor = (bPush.menu === null ? 1 : 0) as PlayerIndex;
    const result = session.intent(notActor, 1, { type: 'localOps.choose', option: 'draw' });
    assert.equal(result.accepted, false);
    if (!result.accepted) assert.equal(result.code, 'NOT_YOUR_TURN');
  });

  it('accepts a legal intent from the current actor and pushes every seat', () => {
    const session = createSession(42, config, ['Alice', 'Bob']);
    const aPush = session.connect(0 as PlayerIndex);
    const actor = (aPush.menu !== null ? 0 : 1) as PlayerIndex;

    const result = session.intent(actor, 1, { type: 'localOps.choose', option: 'draw' });
    assert.equal(result.accepted, true);
    if (result.accepted) assert.equal(result.pushes.size, 2, 'not every connected seat was pushed to');
  });

  it('rejects an illegal intent with its real RejectionCode, and does not remember the seq', () => {
    const session = createSession(42, config, ['Alice', 'Bob']);
    const aPush = session.connect(0 as PlayerIndex);
    const actor = (aPush.menu !== null ? 0 : 1) as PlayerIndex;

    // Discarding before ever drawing is illegal on an opening hand at the limit — a safe "this is
    // definitely rejected" fixture that does not depend on exactly which cards were dealt.
    const bad = session.intent(actor, 1, { type: 'card.discard', cardId: 'not-a-real-card', toSlot: 0 });
    assert.equal(bad.accepted, false);
    if (!bad.accepted) assert.ok(bad.code.length > 0, 'a rejection carried no code at all');

    // The same seq, now with a legal intent, must still go through — a rejection is not "applied".
    const retry = session.intent(actor, 1, { type: 'localOps.choose', option: 'draw' });
    assert.equal(retry.accepted, true, 'a seq burned by an earlier rejection could not be reused');
  });

  it('treats a repeated seq as an already-applied no-op, not a second application', () => {
    const session = createSession(42, config, ['Alice', 'Bob']);
    const aPush = session.connect(0 as PlayerIndex);
    const actor = (aPush.menu !== null ? 0 : 1) as PlayerIndex;

    const first = session.intent(actor, 1, { type: 'localOps.choose', option: 'draw' });
    assert.equal(first.accepted, true);
    const second = session.intent(actor, 1, { type: 'localOps.choose', option: 'draw' });
    assert.equal(second.accepted, true, 'a resend of an already-applied seq was rejected instead of ignored');
    if (second.accepted) assert.equal(second.pushes.size, 0, 'a resend produced pushes as if newly applied');
  });

  it('deltas the board on a second push when it has not changed since the first', () => {
    const session = createSession(42, config, ['Alice', 'Bob']);
    const aPush = session.connect(0 as PlayerIndex);
    session.connect(1 as PlayerIndex); // both seats need a baseline Frame before a delta means anything
    const actor = (aPush.menu !== null ? 0 : 1) as PlayerIndex;

    const result = session.intent(actor, 1, { type: 'localOps.choose', option: 'draw' });
    assert.equal(result.accepted, true);
    if (!result.accepted) return;
    // Choosing "draw" doesn't move a single card on the board — the division/cells should be nulled
    // on this push for a seat that already had them from `connect`.
    const push = result.pushes.get(actor)!;
    assert.equal(push.frame!.division, null, 'the board was resent even though nothing on it changed');
  });

  it('only sends narration NEW since the last push to that specific seat', () => {
    const session = createSession(42, config, ['Alice', 'Bob']);
    const aPush = session.connect(0 as PlayerIndex);
    const actor = (aPush.menu !== null ? 0 : 1) as PlayerIndex;
    // A first connect is this seat's first contact, so it gets everything narrated so far (the
    // "Game Begins" intro and whatever `drain()` said entering the first Stage) — not an empty log.
    assert.ok(aPush.lines.length > 0, 'a first connect got no narration at all, not even the game-begins intro');

    const first = session.intent(actor, 1, { type: 'localOps.choose', option: 'draw' });
    assert.equal(first.accepted, true);
    if (!first.accepted) return;
    const firstLines = first.pushes.get(actor)!.lines;
    assert.ok(firstLines.length > 0, 'the acting seat got no narration for its own action');

    const second = session.intent(actor, 2, { type: 'draw.end' });
    assert.equal(second.accepted, true);
    if (!second.accepted) return;
    const secondLines = second.pushes.get(actor)!.lines;
    assert.ok(secondLines.length > 0, 'a second real action produced no narration at all');
    for (const line of firstLines) {
      assert.ok(!secondLines.includes(line), 'the second push repeated narration already sent in the first');
    }
  });
});

describe('turn timings (lobby-and-sessions.md §5)', () => {
  it('records a wall-clock span once the acting player, phase, Day or Stage changes', () => {
    const session = createSession(42, config, ['Alice', 'Bob']);
    let pushes = new Map<PlayerIndex, Push>([
      [0 as PlayerIndex, session.connect(0 as PlayerIndex)],
      [1 as PlayerIndex, session.connect(1 as PlayerIndex)],
    ]);
    const seq = new Map<PlayerIndex, number>([[0 as PlayerIndex, 1], [1 as PlayerIndex, 1]]);
    const timings = [];

    for (let step = 0; step < 60 && timings.length === 0; step++) {
      const acting = [0, 1].find((seat) => pushes.get(seat as PlayerIndex)!.menu !== null) as PlayerIndex | undefined;
      const menu = acting === undefined ? null : pushes.get(acting)!.menu;
      if (acting === undefined || !menu || menu.options.length === 0) break;

      const n = seq.get(acting)!;
      seq.set(acting, n + 1);
      const result = session.intent(acting, n, menu.options[0]!);
      assert.equal(result.accepted, true, `step ${step}: ${JSON.stringify(menu.options[0])} rejected`);
      if (!result.accepted) break;
      if (result.timing) timings.push(result.timing);
      pushes = result.pushes;
    }

    assert.ok(timings.length > 0, 'no turn timing ever closed across 60 real steps of actual play');
    const [timing] = timings;
    assert.ok(timing!.endedAt >= timing!.startedAt, 'a span ended before it started');
    assert.ok([0, 1].includes(timing!.player), 'a timing named a player outside the table');
  });
});

describe('bot seats (Phase 4 — D8, lobby-and-sessions.md §2)', () => {
  it('a bot never becomes the observable current actor — it plays before anyone can see it waiting', () => {
    // Seat 0 acts first (the opening Superintendent), so marking it a bot exercises `driveBots()`
    // at CONSTRUCTION time — before any external `intent()` has run at all.
    const session = createSession(11, config, ['Bot', 'Alice'], [0 as PlayerIndex]);
    assert.equal(session.isBot(0 as PlayerIndex), true);
    assert.equal(session.isBot(1 as PlayerIndex), false);

    const botPush = session.connect(0 as PlayerIndex);
    const humanPush = session.connect(1 as PlayerIndex);
    assert.equal(botPush.menu, null, 'the bot seat was handed a real decision to make');
    assert.notEqual(humanPush.menu, null, 'nobody was left with a turn to take — the bot never played');
  });

  it('botSeats round-trips through exportSave/resumeSession', () => {
    const session = createSession(11, config, ['Bot', 'Alice'], [0 as PlayerIndex]);
    const resumed = resumeSession(session.exportSave());
    assert.equal(resumed.isBot(0 as PlayerIndex), true);
    assert.equal(resumed.connect(0 as PlayerIndex).menu, null, 'a resumed bot seat still never gets a real decision');
  });

  it('a bot seat is driven forward after a human intent too, not only at construction', () => {
    // Two bots and one human: whichever of the two non-human seats comes up next after the human's
    // own move must be played automatically, with no external `intent()` for either of them.
    const session = createSession(11, config, ['Alice', 'Bot', 'Bot'], [1 as PlayerIndex, 2 as PlayerIndex]);
    const before = session.exportSave().history.length;
    const applied = session.intent(0 as PlayerIndex, 1, { type: 'localOps.choose', option: 'draw' });
    assert.equal(applied.accepted, true);
    assert.equal(session.connect(1 as PlayerIndex).menu, null, 'bot seat 1 was left with a real decision');
    assert.equal(session.connect(2 as PlayerIndex).menu, null, 'bot seat 2 was left with a real decision');
    // Not a strict proof either bot actually moved (the human's own turn may not have ended yet),
    // but the history can only ever have grown, never shrunk, and never rejected mid-drive.
    assert.ok(session.exportSave().history.length >= before + 1);
  });
});

describe('persistence hooks — exportSave / resumeSession (Phase 3)', () => {
  it('exportSave carries enough to reconstruct the exact same game', () => {
    const session = createSession(42, config, ['Alice', 'Bob']);
    const push = session.connect(0 as PlayerIndex);
    const actor = (push.menu !== null ? 0 : 1) as PlayerIndex;
    const applied = session.intent(actor, 1, { type: 'localOps.choose', option: 'draw' });
    assert.equal(applied.accepted, true);

    const saved = session.exportSave();
    assert.equal(saved.seed, 42);
    assert.deepEqual(saved.playerNames, ['Alice', 'Bob']);
    assert.equal(saved.history.length, 1);
    assert.equal(saved.status, 'active');
    assert.ok(saved.createdAt > 0, 'createdAt was not set');

    const resumed = resumeSession(saved);
    const before = session.connect(actor);
    const after = resumed.connect(actor);
    assert.deepEqual(after.frame, before.frame, 'resumeSession did not reconstruct the same board/state');
  });

  it('a resumed session keeps enforcing whose turn it is', () => {
    const session = createSession(7, config, ['Alice', 'Bob']);
    const push = session.connect(0 as PlayerIndex);
    const actor = (push.menu !== null ? 0 : 1) as PlayerIndex;
    session.intent(actor, 1, { type: 'localOps.choose', option: 'draw' });

    const resumed = resumeSession(session.exportSave());
    const notActor = (actor === 0 ? 1 : 0) as PlayerIndex;
    const rejected = resumed.intent(notActor, 1, { type: 'draw.end' });
    assert.equal(rejected.accepted, false);
    if (!rejected.accepted) assert.equal(rejected.code, 'NOT_YOUR_TURN');
  });

  it('marks status finished only once the game actually is', () => {
    const session = createSession(42, config, ['Alice', 'Bob']);
    assert.equal(session.exportSave().status, 'active');
  });
});

describe('summary() — what an administrator sees without replaying the game', () => {
  it('describes a fresh game: who is at the table, where it has got to, and who it waits on', () => {
    const session = createSession(42, config, ['Alice', 'Bob']);
    const s = session.summary();

    assert.equal(s.playerCount, 2);
    assert.deepEqual(s.playerNames, ['Alice', 'Bob']);
    assert.equal(s.status, 'active');
    assert.equal(s.day, 1);
    assert.equal(s.stage, 1);
    assert.equal(typeof s.phase, 'string');
    assert.ok(s.waitingOn, 'a game in play must be waiting on somebody');
    assert.equal(s.waitingOn!.name, s.playerNames[s.waitingOn!.seat]);
  });

  it('does not hand back a copy of the history the way exportSave must', () => {
    // The health check polls this on a timer, so it answering with every intent of every game
    // would make a question about none of them cost a copy of all of them.
    const session = createSession(42, config, ['Alice', 'Bob']);
    assert.equal('history' in session.summary(), false);
  });

  it('moves lastMoveAt when a move is accepted, and leaves it alone when one is refused', async () => {
    const session = createSession(42, config, ['Alice', 'Bob']);
    const created = session.summary();
    assert.equal(created.lastMoveAt, created.createdAt, 'an untouched game has not moved since it began');

    const actor = (session.connect(0 as PlayerIndex).menu !== null ? 0 : 1) as PlayerIndex;
    const idle = (1 - actor) as PlayerIndex;

    // A rejection is not a move — a player poking at a game they cannot act in must not make it
    // look alive to whoever is deciding whether it has stalled.
    session.intent(idle, 1, { type: 'localOps.choose', option: 'draw' });
    assert.equal(session.summary().lastMoveAt, created.lastMoveAt, 'a refused intent moved the clock');

    await new Promise((r) => setTimeout(r, 2));
    const accepted = session.intent(actor, 1, { type: 'localOps.choose', option: 'draw' });
    assert.equal(accepted.accepted, true);
    assert.ok(session.summary().lastMoveAt > created.lastMoveAt, 'an accepted intent did not move the clock');
  });

  it('carries lastMoveAt across a restart, and falls back to createdAt for a save without one', async () => {
    const session = createSession(42, config, ['Alice', 'Bob']);
    const actor = (session.connect(0 as PlayerIndex).menu !== null ? 0 : 1) as PlayerIndex;
    await new Promise((r) => setTimeout(r, 2));
    session.intent(actor, 1, { type: 'localOps.choose', option: 'draw' });

    const saved = session.exportSave();
    assert.equal(resumeSession(saved).summary().lastMoveAt, saved.lastMoveAt);

    // A game written before the field existed still has to load, and reads as untouched since it
    // began rather than as having just moved.
    const { lastMoveAt: _dropped, ...older } = saved;
    const revived = resumeSession(older).summary();
    assert.equal(revived.lastMoveAt, saved.createdAt);
  });

  it('reports a finished game as waiting on nobody', () => {
    // Every seat a bot, so the game plays itself to a finish inside the constructor.
    const session = createSession(4242, config, ['A', 'B'], [0 as PlayerIndex, 1 as PlayerIndex]);
    const s = session.summary();
    assert.equal(s.status, 'finished');
    assert.equal(s.waitingOn, null, 'a finished game must not name somebody to wait for');
  });
});

describe('a save survives a release that did not change the rules', () => {
  /** Plays a couple of real moves so the history is worth replaying. */
  const played = (): ReturnType<GameSession['exportSave']> => {
    const s = createSession(42, config, ['Alice', 'Bob']);
    const actor = (s.connect(0 as PlayerIndex).menu !== null ? 0 : 1) as PlayerIndex;
    s.intent(actor, 1, { type: 'localOps.choose', option: 'draw' });
    return s.exportSave();
  };

  it('resumes whatever version stamped it, so long as the moves still replay', () => {
    // This is the whole point. The engine version used to gate this, and it is the PACKAGE version
    // — it moves for a CSS fix. Four releases in a row destroyed every game in progress, one of
    // them for a change that only altered how the board is drawn.
    const saved = played();
    const r = tryResumeSession(saved);
    assert.equal(r.ok, true, 'a replayable save was refused');
    if (!r.ok) return;
    assert.deepEqual(r.session.exportSave().history, saved.history);
  });

  it('refuses a save whose moves no longer replay, and says which move and why', () => {
    // A rules change is simulated by corrupting one intent — the engine cannot apply it, which is
    // exactly the shape a genuinely incompatible save has.
    const saved = played();
    const broken = {
      ...saved,
      history: [...saved.history, { type: 'localOps.choose', option: 'not-a-real-option' } as never],
    };
    const r = tryResumeSession(broken);
    assert.equal(r.ok, false, 'a save the rules reject was accepted');
    if (r.ok) return;
    assert.equal(r.failure.of, broken.history.length);
    assert.equal(r.failure.stoppedAt, broken.history.length - 1, 'wrong move blamed');
    assert.equal(r.failure.intent, 'localOps.choose');
    assert.ok(r.failure.code.length > 0, 'no rejection code to act on');
  });

  it('never silently truncates — the old loop stopped at a bad move and said nothing', () => {
    // The silence was survivable only because the version check meant a doomed replay was never
    // attempted. Now that the replay IS the check, a partial one must be impossible to mistake for
    // a whole one.
    const saved = played();
    const broken = { ...saved, history: [{ type: 'draw.end' } as never, ...saved.history] };
    const r = tryResumeSession(broken);
    assert.equal(r.ok, false, 'a truncated replay was returned as a healthy session');
  });
});