import { describe, expect, it } from 'vitest';

import {
    GAME_TICKS_PER_TURN,
    GameClock,
    MAX_SAFE_GAME_TICK,
    asGameTick,
    asObservedGameInstant,
    buildExactClockAlignmentPlan,
    createDeadline,
    scheduleNotBefore,
} from '../src/time/GameClock.js';

describe('GameClock', () => {
    const baseTime = new Date('2042-01-01T00:00:00.000Z');

    it('projects the fixed Ref turn tick and ignores wall time in manual mode', () => {
        const clock = new GameClock({
            baseTime,
            tick: GAME_TICKS_PER_TURN,
            mode: 'manual',
            wallAnchor: new Date('2026-01-01T00:00:00.000Z'),
            turnSeconds: 3_600,
        });

        expect(clock.ticksPerSecond).toBe(10_000);
        expect(clock.nowTick(new Date('2126-01-01T00:00:00.000Z'))).toBe(GAME_TICKS_PER_TURN);
        expect(clock.now(new Date('2126-01-01T00:00:00.000Z')).toISOString()).toBe('2042-01-01T01:00:00.000Z');
    });

    it('accepts a large forward wall jump without losing tick precision', () => {
        const wallAnchor = new Date('2026-01-01T00:00:00.000Z');
        const clock = new GameClock({
            baseTime,
            tick: 0,
            mode: 'realtime',
            wallAnchor,
            turnSeconds: 7_200,
        });
        const jumped = new Date('2126-01-01T00:00:00.000Z');
        const tick = clock.nowTick(jumped);

        expect(Number.isSafeInteger(tick)).toBe(true);
        expect(clock.tickToDate(tick).getTime() - baseTime.getTime()).toBe(jumped.getTime() - wallAnchor.getTime());
    });

    it('projects a negative tick before a future realtime anchor', () => {
        const clock = new GameClock({
            baseTime,
            tick: 0,
            mode: 'realtime',
            wallAnchor: new Date('2026-01-01T01:00:00.000Z'),
            turnSeconds: 3_600,
            phase: 'PREOPEN',
        });

        expect(clock.nowTick(new Date('2026-01-01T00:30:00.000Z'))).toBe(-GAME_TICKS_PER_TURN / 2);
        expect(clock.nowTick(new Date('2026-01-01T01:00:00.000Z'))).toBe(0);
    });

    it('does not rewind a RUNNING realtime tick when wall time moves backward', () => {
        const clock = new GameClock({
            baseTime,
            tick: GAME_TICKS_PER_TURN,
            mode: 'realtime',
            wallAnchor: new Date('2026-01-01T01:00:00.000Z'),
            turnSeconds: 3_600,
            phase: 'RUNNING',
            revision: 7,
        });

        expect(clock.nowTick(new Date('2026-01-01T00:59:55.000Z'))).toBe(GAME_TICKS_PER_TURN);
        expect(clock.revision).toBe(7);
    });

    it('floors PREOPEN executable schedules at opening tick zero', () => {
        const observed = asObservedGameInstant(-GAME_TICKS_PER_TURN / 2);

        expect(scheduleNotBefore(observed, 'PREOPEN')).toBe(0);
        expect(createDeadline(observed, asGameTick(GAME_TICKS_PER_TURN / 4), 'PREOPEN')).toBe(0);
        expect(scheduleNotBefore(observed, 'RUNNING')).toBe(observed);
    });

    it('preserves a 65 minute 17.250 second sub-turn suspension remainder exactly', () => {
        const plan = buildExactClockAlignmentPlan({
            sourceRevision: 11,
            cutTick: 123_456,
            cutWall: new Date('2026-01-01T00:00:00.000Z'),
            resumeWall: new Date('2026-01-01T01:05:17.250Z'),
            ticksPerSecond: 10_000,
        });

        expect(plan).toMatchObject({
            sourceRevision: 11,
            targetRevision: 12,
            gapTicks: 39_172_500,
            shiftTicks: 39_172_500,
            alignedTick: 39_295_956,
        });
        expect(plan.shiftTicks % GAME_TICKS_PER_TURN).toBe(3_172_500);
    });

    it('aligns a 24 hour exact maintenance without catch-up', () => {
        const plan = buildExactClockAlignmentPlan({
            sourceRevision: 1,
            cutTick: 2 * GAME_TICKS_PER_TURN,
            cutWall: new Date('2026-01-01T00:00:00.000Z'),
            resumeWall: new Date('2026-01-02T00:00:00.000Z'),
            ticksPerSecond: 10_000,
        });

        expect(plan.gapTicks).toBe(24 * GAME_TICKS_PER_TURN);
        expect(plan.alignedTick).toBe(26 * GAME_TICKS_PER_TURN);
    });

    it('projects near the safe tick boundary without unsafe intermediate multiplication', () => {
        const clock = new GameClock({
            baseTime: new Date(0),
            tick: 0,
            mode: 'manual',
            wallAnchor: new Date(0),
            turnSeconds: 7_200,
        });
        const tick = MAX_SAFE_GAME_TICK - (MAX_SAFE_GAME_TICK % clock.ticksPerSecond);
        const projected = clock.tickToDate(tick);

        expect(Number.isNaN(projected.getTime())).toBe(false);
        expect(clock.dateToTick(projected)).toBe(tick);
    });

    it('truncates sub-millisecond projections like Ref GameClock', () => {
        const clock = new GameClock({
            baseTime,
            tick: 0,
            mode: 'manual',
            wallAnchor: baseTime,
            turnSeconds: 600,
        });

        expect(clock.tickToDate(14_115_919).toISOString()).toBe('2042-01-01T00:03:55.265Z');
        expect(clock.tickToDate(-1).toISOString()).toBe('2041-12-31T23:59:59.999Z');
    });
});