import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest';
import { newFixture, type Fixture } from '../helpers/fixture.js';
import { parseMetricsQuery } from '../../src/lib/metrics.js';

let fixture: Fixture;
beforeEach(async () => { vi.resetModules(); fixture = await newFixture([]); });
afterEach(async () => { vi.restoreAllMocks(); await fixture.cleanup(); });

describe('historical metrics', () => {
    it('weights occupancy by time and excludes failed checks and collection gaps', async () => {
        const { recordMetrics, readMetrics } = await import('../../src/lib/server/fleet/metrics.js');
        const sample = { server: 'one', game: 't5', map: 'Moon', players: 2, capacity: 4 };
        const at = Date.UTC(2026, 0, 2, 12);
        recordMetrics([sample], at);
        recordMetrics([{ ...sample, players: 0 }], at + 30_000);
        recordMetrics([{ ...sample, players: null }], at + 60_000);
        const result = readMetrics(1, at + 3600_000);
        expect(result.summary.active * 3600).toBeCloseTo(30);
        expect(result.summary.idle * 3600).toBeCloseTo(30);
        expect(result.summary.unknown * 3600).toBeCloseTo(90);
        expect(result.summary.playerHours * 3600).toBeCloseTo(60);
        expect(result.points.reduce((sum, p) => sum + p.observed, 0)).toBeCloseTo(result.summary.observed);
    });

    it('only counts map saturation when every lobby has known capacity and is full', async () => {
        const { recordMetrics, readMetrics } = await import('../../src/lib/server/fleet/metrics.js');
        const at = Date.UTC(2026, 0, 2, 12);
        const sample = { server: 'one', game: 't5', map: 'Moon', players: 4, capacity: 4 };
        recordMetrics([sample, { ...sample, server: 'two' }], at);
        recordMetrics([sample, { ...sample, server: 'two', players: 2 }], at + 30_000);
        recordMetrics([sample, { ...sample, server: 'two', capacity: null }], at + 60_000);
        recordMetrics([sample, { ...sample, server: 'two', players: null }], at + 90_000);
        const result = readMetrics(1, at + 120_000);
        expect(result.maps[0].full * 3600).toBeCloseTo(30);
        expect(result.maps[0].capacityObserved * 3600).toBeCloseTo(60);
    });

    it('clips the reporting window and splits observations across UTC chart boundaries', async () => {
        const { recordMetrics, readMetrics } = await import('../../src/lib/server/fleet/metrics.js');
        const midnight = Date.UTC(2026, 0, 2);
        const sample = { server: 'one', game: 't5', map: 'Moon', players: 1, capacity: 4 };
        recordMetrics([sample], midnight - 15_000);
        let result = readMetrics(1, midnight + 15_000);
        expect(result.points.filter(p => p.active > 0).map(p => p.active * 3600)).toEqual([15, 15]);
        result = readMetrics(1, midnight + 86400_000);
        expect(result.summary.active * 3600).toBeCloseTo(75);
        expect(result.points.reduce((sum, p) => sum + p.active, 0)).toBeCloseTo(result.summary.active);
    });

    it('retains history without a live server and prunes observations older than 31 days', async () => {
        const { recordMetrics, readMetrics } = await import('../../src/lib/server/fleet/metrics.js');
        const { db } = await import('../../src/lib/server/db/index.js');
        const at = Date.UTC(2026, 0, 2);
        const sample = { server: 'removed', game: 't6', map: 'Town', players: 1, capacity: null };
        recordMetrics([sample], at);
        expect(readMetrics(1, at + 30_000).servers[0].server).toBe('removed');
        recordMetrics([sample], at + 32 * 86400_000);
        expect(db().prepare('SELECT COUNT(*) AS n FROM metric_samples').get()).toEqual({ n: 1 });
    });

    it('distinguishes retained history, an empty range, and current collection targets', async () => {
        const { recordMetrics, readMetrics } = await import('../../src/lib/server/fleet/metrics.js');
        const { db } = await import('../../src/lib/server/db/index.js');
        const at = Date.UTC(2026, 0, 2);
        expect(readMetrics(1, at)).toMatchObject({ firstRetainedSampleAt: null, latestSampleAt: null,
            registeredServerCount: 0, servers: [], maps: [] });
        db().prepare('INSERT INTO servers (name, destroyed_at) VALUES (?, ?)').run('current', null);
        db().prepare('INSERT INTO servers (name, destroyed_at) VALUES (?, ?)').run('removed', new Date(at).toISOString());
        const sample = { server: 'removed', game: 't6', map: 'Town', players: 1, capacity: null };
        recordMetrics([sample], at);
        const emptyRange = readMetrics(1, at + 2 * 86400_000);
        expect(emptyRange).toMatchObject({ firstRetainedSampleAt: at, latestSampleAt: at,
            registeredServerCount: 1, servers: [], maps: [], summary: { observed: 0, unknown: 0 } });
        expect(emptyRange.points.every(point => point.observed === 0 && point.unknown === 0)).toBe(true);
    });

    it('keeps unknown status separate from no samples and preserves zero elapsed observations', async () => {
        const { recordMetrics, readMetrics } = await import('../../src/lib/server/fleet/metrics.js');
        const at = Date.UTC(2026, 0, 2, 12);
        recordMetrics([{ server: 'one', game: 't5', map: 'Moon', players: null, capacity: null }], at);
        const initial = readMetrics(1, at);
        expect(initial.latestSampleAt).toBe(at);
        expect(initial.servers).toHaveLength(1);
        expect(initial.summary).toEqual({ observed: 0, active: 0, idle: 0, unknown: 0, playerHours: 0 });
        const later = readMetrics(1, at + 120_000);
        expect(later.summary.observed).toBe(0);
        expect(later.summary.unknown * 3600).toBeCloseTo(90);
        expect(later.maps[0].capacityObserved).toBe(0);
    });

    it('returns clipped interval boundaries and marks only partial UTC buckets', async () => {
        const { readMetrics } = await import('../../src/lib/server/fleet/metrics.js');
        const now = Date.UTC(2026, 0, 8, 12, 30);
        for (const days of [1, 7, 30] as const) {
            const result = readMetrics(days, now);
            expect(result.points[0].startAt).toBe(result.since);
            expect(result.points.at(-1)?.endAt).toBe(now);
            expect(result.points[0].partial).toBe(true);
            expect(result.points.at(-1)?.partial).toBe(true);
            expect(result.points.slice(1, -1).every(point => !point.partial)).toBe(true);
            expect(result.points.reduce((ms, point) => ms + point.endAt - point.startAt, 0)).toBe(days * 86400_000);
        }
        expect(readMetrics(1, Date.UTC(2026, 0, 8, 12)).points.every(point => !point.partial)).toBe(true);
    });

    it('uses complete collection boundaries across fleet changes and keeps map pressure in wall time', async () => {
        const { recordMetrics, readMetrics } = await import('../../src/lib/server/fleet/metrics.js');
        const at = Date.UTC(2026, 0, 2, 23, 59, 40);
        const one = { server: 'one', game: 't6', map: 'Town', players: 4, capacity: 4 };
        const two = { ...one, server: 'two' };
        recordMetrics([one, two], at);
        // Removing a lobby ends its previous observation at the next complete collection.
        recordMetrics([{ ...one, map: 'Farm', players: 0 }], at + 30_000);
        // A collection outage is excluded; an identically named map in another game remains separate.
        recordMetrics([{ ...one, game: 't5', players: 2, capacity: null }], at + 150_000);
        const result = readMetrics(1, at + 180_000);
        expect(result.summary.active * 3600).toBeCloseTo(90);
        expect(result.summary.idle * 3600).toBeCloseTo(90);
        expect(result.summary.playerHours * 3600).toBeCloseTo(300);
        expect(result.servers.find(server => server.server === 'two')!.observed * 3600).toBeCloseTo(30);
        const town = result.maps.find(map => map.game === 't6' && map.map === 'Town')!;
        expect(town.observed * 3600).toBeCloseTo(60);
        expect(town.capacityObserved * 3600).toBeCloseTo(30);
        expect(town.full * 3600).toBeCloseTo(30);
        expect(result.maps.find(map => map.game === 't5')!.capacityObserved).toBe(0);
        for (const field of ['observed', 'active', 'idle', 'unknown', 'playerHours'] as const) {
            expect(result.points.reduce((sum, point) => sum + point[field], 0)).toBeCloseTo(result.summary[field]);
            expect(result.servers.reduce((sum, server) => sum + server[field], 0)).toBeCloseTo(result.summary[field]);
            expect(result.maps.reduce((sum, map) => sum + map[field], 0)).toBeCloseTo(result.summary[field]);
        }
    });

    it('does not include future samples in collection metadata or aggregates', async () => {
        const { recordMetrics, readMetrics } = await import('../../src/lib/server/fleet/metrics.js');
        const at = Date.UTC(2026, 0, 2, 12);
        const sample = { server: 'one', game: 't5', map: 'Moon', players: 1, capacity: 4 };
        recordMetrics([sample], at);
        recordMetrics([{ ...sample, players: 4 }], at + 60_000);
        const result = readMetrics(1, at + 30_000);
        expect(result.latestSampleAt).toBe(at);
        expect(result.summary.playerHours * 3600).toBeCloseTo(30);
    });

    it('shares the range parser and response contract between SSR and the uncached refresh endpoint', async () => {
        const { recordMetrics } = await import('../../src/lib/server/fleet/metrics.js');
        const { GET } = await import('../../src/routes/api/metrics/+server.js');
        const { load } = await import('../../src/routes/metrics/+page.server.js');
        const at = Date.UTC(2026, 0, 2, 12);
        recordMetrics([{ server: 'one', game: 't5', map: 'Moon', players: 2, capacity: 4 }], at);
        vi.spyOn(Date, 'now').mockReturnValue(at + 30_000);
        for (const range of ['1', '7', '30', 'invalid', '365', '-1', '']) {
            const url = new URL(`http://localhost/metrics?days=${range}`);
            const response = await GET({ url });
            const payload = await response.json();
            expect(response.headers.get('cache-control')).toBe('no-store');
            expect(payload).toEqual(await load({ url } as Parameters<typeof load>[0]));
            expect(payload.days).toBe(['1', '7', '30'].includes(range) ? Number(range) : 7);
        }
        expect((await (await GET({ url: new URL('http://localhost/api/metrics') })).json()).days).toBe(7);
        for (const search of ['days=1&game=t5&map=Moon&timeZone=Asia%2FKathmandu', 'days=7&map=Moon', 'game=t6&timeZone=Invalid']) {
            const url = new URL(`http://localhost/metrics?${search}`);
            const payload = await (await GET({ url })).json();
            const { days, ...scope } = parseMetricsQuery(url.searchParams);
            expect(payload).toEqual(await load({ url } as Parameters<typeof load>[0]));
            expect(payload).toMatchObject({ days, scope });
        }
    });

    it('normalizes malformed scopes consistently and requires a game for a map selection', () => {
        expect(parseMetricsQuery(new URLSearchParams('days=365&map=Moon&timeZone=Invalid/Zone')))
            .toEqual({ days: 7, game: null, map: null, timeZone: 'America/New_York' });
        expect(parseMetricsQuery(new URLSearchParams({ game: 't5; DROP TABLE', map: 'Moon' }))).toMatchObject({ game: null, map: null });
        expect(parseMetricsQuery(new URLSearchParams({ game: ' t5 ', map: 'Moon', timeZone: 'Asia/Kathmandu', days: '30' })))
            .toEqual({ days: 30, game: 't5', map: 'Moon', timeZone: 'Asia/Kathmandu' });
        for (const map of ['', ' ', 'a'.repeat(201), 'Moon\nTown']) {
            expect(parseMetricsQuery(new URLSearchParams({ game: 't5', map })).map).toBeNull();
        }
        expect(parseMetricsQuery(new URLSearchParams({ game: 't5', map: 'Not recorded yet' })).map).toBe('Not recorded yet');
    });

    it('filters every derived value by exact game and map while preserving unfiltered collection boundaries', async () => {
        const { recordMetrics, readMetrics } = await import('../../src/lib/server/fleet/metrics.js');
        const now = Date.UTC(2026, 0, 3, 12);
        const since = now - 86400_000;
        const moon = { server: 'one', game: 't5', map: 'Moon', players: 4, capacity: 4 };
        const other = { ...moon, server: 'other', game: 't6', players: 2 };
        recordMetrics([moon, other], since - 30_000);
        recordMetrics([other], since);
        recordMetrics([moon, other, { ...moon, server: 'town', map: 'Town', players: 0 }], now - 60_000);
        recordMetrics([other], now - 45_000);
        recordMetrics([{ ...moon, players: 0 }, other], now - 30_000);
        const query = parseMetricsQuery(new URLSearchParams({ days: '1', game: 't5', map: 'Moon', timeZone: 'UTC' }));
        const result = readMetrics(query, now);
        expect(result.scope).toEqual({ game: 't5', map: 'Moon', timeZone: 'UTC' });
        expect(result.summary.active * 3600).toBeCloseTo(15);
        expect(result.summary.idle * 3600).toBeCloseTo(30);
        expect(result.summary.playerHours * 3600).toBeCloseTo(60);
        expect(result.previous.summary.active * 3600).toBeCloseTo(30);
        expect(result.previous.summary.playerHours * 3600).toBeCloseTo(120);
        expect(result.servers.map(server => server.server)).toEqual(['one']);
        expect(result.maps.map(map => [map.game, map.map])).toEqual([['t5', 'Moon']]);
        expect(result.scopeOptions).toEqual({ games: ['t5', 't6'], maps: [
            { game: 't5', map: 'Moon' }, { game: 't5', map: 'Town' }, { game: 't6', map: 'Moon' }
        ] });
        expect(result.scopeFirstSampleAt).toBe(since - 30_000);
        expect(result.scopeLatestSampleAt).toBe(now - 30_000);
        expect(result.pooledPressure.value).toBeCloseTo(100 / 3);
        for (const field of ['observed', 'active', 'idle', 'unknown', 'playerHours'] as const) {
            expect(result.points.reduce((sum, point) => sum + point[field], 0)).toBeCloseTo(result.summary[field]);
            expect(result.heatmap.cells.reduce((sum, cell) => sum + cell[field], 0)).toBeCloseTo(result.summary[field]);
        }
        const gameOnly = readMetrics({ ...query, map: null }, now);
        expect(gameOnly.maps.map(map => map.map).sort()).toEqual(['Moon', 'Town']);
        const missing = readMetrics({ ...query, map: 'Unrecorded' }, now);
        expect(missing).toMatchObject({ scopeFirstSampleAt: null, scopeLatestSampleAt: null,
            summary: { observed: 0, unknown: 0 }, maps: [], servers: [], pooledPressure: { value: null },
            previous: { firstSampleAt: null, lastSampleAt: null, partialHistory: true } });
        expect(missing.scopeOptions).toEqual(result.scopeOptions);
    });

    it('separates scoped evidence timestamps from global collection timestamps', async () => {
        const { recordMetrics, readMetrics } = await import('../../src/lib/server/fleet/metrics.js');
        const at = Date.UTC(2026, 0, 3, 12);
        const sample = { server: 'one', game: 't5', map: 'Moon', players: 1, capacity: 4 };
        recordMetrics([{ ...sample, game: 't6' }], at - 60_000);
        recordMetrics([sample], at - 30_000);
        recordMetrics([{ ...sample, game: 't6' }], at);
        const result = readMetrics(parseMetricsQuery(new URLSearchParams({ game: 't5' })), at + 30_000);
        expect(result.firstRetainedSampleAt).toBe(at - 60_000);
        expect(result.latestSampleAt).toBe(at);
        expect(result.scopeFirstSampleAt).toBe(at - 30_000);
        expect(result.scopeLatestSampleAt).toBe(at - 30_000);
    });

    it('compares adjacent equal windows and splits an observation at their shared boundary', async () => {
        const { recordMetrics, readMetrics } = await import('../../src/lib/server/fleet/metrics.js');
        const now = Date.UTC(2026, 0, 3, 12);
        const since = now - 86400_000;
        const sample = { server: 'one', game: 't5', map: 'Moon', players: 2, capacity: 4 };
        recordMetrics([sample], since - 15_000);
        recordMetrics([{ ...sample, players: 0 }], since + 15_000);
        const result = readMetrics(1, now);
        expect(result.previous.since).toBe(now - 2 * 86400_000);
        expect(result.previous.until).toBe(result.since);
        expect(result.previous.summary.active * 3600).toBeCloseTo(15);
        expect(result.summary.active * 3600).toBeCloseTo(15);
        expect(result.summary.idle * 3600).toBeCloseTo(90);
        expect(result.previous).toMatchObject({ firstSampleAt: since - 15_000, lastSampleAt: since - 15_000, partialHistory: true });
    });

    it('returns the available prior evidence when a thirty-day comparison exceeds retained history', async () => {
        const { recordMetrics, readMetrics } = await import('../../src/lib/server/fleet/metrics.js');
        const now = Date.UTC(2026, 2, 3, 12);
        const day = 86400_000;
        const sample = { server: 'one', game: 't5', map: 'Moon', players: 2, capacity: 4 };
        recordMetrics([sample], now - 31 * day + 30_000);
        recordMetrics([{ ...sample, players: 0 }], now - 30 * day + 30_000);
        recordMetrics([sample], now - 30_000);
        const result = readMetrics(30, now);
        expect(result.previous).toMatchObject({ since: now - 60 * day, until: now - 30 * day, partialHistory: true });
        expect(result.previous.summary.active * 3600).toBeCloseTo(90);
        expect(result.previous.firstSampleAt).toBe(now - 31 * day + 30_000);
        expect(result.summary.active * 3600).toBeCloseTo(30);
        expect(result.summary.idle * 3600).toBeCloseTo(90);
    });

    it('marks the retained start bound separately from gaps inside the previous window', async () => {
        const { recordMetrics, readMetrics } = await import('../../src/lib/server/fleet/metrics.js');
        const now = Date.UTC(2026, 0, 3, 12);
        const priorStart = now - 2 * 86400_000;
        const sample = { server: 'one', game: 't5', map: 'Moon', players: null, capacity: null };
        recordMetrics([sample], priorStart - 15_000);
        recordMetrics([sample], now - 30_000);
        const result = readMetrics(1, now);
        expect(result.previous.partialHistory).toBe(false);
        expect(result.previous.summary.unknown * 3600).toBeCloseTo(75);
        expect(result.previous.summary.observed).toBe(0);
        expect(result.previous.firstSampleAt).toBe(priorStart - 15_000);
        // Having the left edge says nothing about the uncaptured time after it.
        expect(result.previous.summary.unknown).toBeLessThan(24);
    });

    it('pools pressure by known map-hours rather than server-hours or fleet elapsed time', async () => {
        const { recordMetrics, readMetrics } = await import('../../src/lib/server/fleet/metrics.js');
        const at = Date.UTC(2026, 0, 3, 12);
        const full = { server: 'one', game: 't5', map: 'Moon', players: 4, capacity: 4 };
        recordMetrics([full, { ...full, server: 'two' }, { ...full, server: 'three', map: 'Town', players: 0 },
            { ...full, server: 'four', map: 'Farm', players: 2, capacity: null }], at);
        const result = readMetrics(1, at + 30_000);
        expect(result.pooledPressure).toMatchObject({ value: 50, coveredMaps: 2, totalMaps: 3 });
        expect(result.pooledPressure.fullMapHours * 3600).toBeCloseTo(30);
        expect(result.pooledPressure.knownMapHours * 3600).toBeCloseTo(60);
        expect(result.summary.observed * 3600).toBeCloseTo(120);
        const empty = readMetrics(parseMetricsQuery(new URLSearchParams({ days: '1', game: 't5', map: 'Town' })), at + 30_000);
        expect(empty.pooledPressure.value).toBe(0);
        const missing = readMetrics(parseMetricsQuery(new URLSearchParams({ days: '1', game: 't5', map: 'Farm' })), at + 30_000);
        expect(missing.pooledPressure.value).toBeNull();
    });

    it.each([
        { zone: 'America/New_York', at: '2026-03-08T06:59:45Z', first: [6, 1], second: [6, 3] },
        { zone: 'Asia/Kolkata', at: '2026-01-01T18:29:45Z', first: [3, 23], second: [4, 0] },
        { zone: 'Asia/Kathmandu', at: '2026-01-01T18:14:45Z', first: [3, 23], second: [4, 0] },
        { zone: 'Australia/Lord_Howe', at: '2026-10-03T15:29:45Z', first: [6, 1], second: [6, 2] }
    ])('splits heatmap time across local boundaries in $zone', async ({ zone, at: timestamp, first, second }) => {
        const { recordMetrics, readMetrics } = await import('../../src/lib/server/fleet/metrics.js');
        const at = Date.parse(timestamp);
        recordMetrics([{ server: 'one', game: 't5', map: 'Moon', players: 2, capacity: 4 }], at);
        const result = readMetrics(parseMetricsQuery(new URLSearchParams({ days: '1', timeZone: zone })), at + 30_000);
        expect(result.heatmap.timeZone).toBe(zone);
        expect(result.heatmap.cells).toHaveLength(168);
        for (const [weekday, hour] of [first, second]) {
            const cell = result.heatmap.cells.find(cell => cell.weekday === weekday && cell.hour === hour)!;
            expect(cell.observed * 3600).toBeCloseTo(15);
            expect(cell.playerHours * 3600).toBeCloseTo(30);
            expect(cell.distinctDates).toBe(1);
        }
        expect(result.heatmap.cells.reduce((sum, cell) => sum + cell.observed, 0)).toBeCloseTo(result.summary.observed);
    });

    it('weights repeated fall-back hours and counts their local date once', async () => {
        const { recordMetrics, readMetrics } = await import('../../src/lib/server/fleet/metrics.js');
        const at = Date.parse('2026-11-01T05:30:00Z');
        const sample = { server: 'one', game: 't5', map: 'Moon', players: 2, capacity: 4 };
        recordMetrics([sample], at);
        recordMetrics([{ ...sample, players: 0 }], at + 3600_000);
        const result = readMetrics(parseMetricsQuery(new URLSearchParams({ days: '1', timeZone: 'America/New_York' })), at + 3630_000);
        const cell = result.heatmap.cells.find(cell => cell.weekday === 6 && cell.hour === 1)!;
        expect(cell.observed * 3600).toBeCloseTo(120);
        expect(cell.active * 3600).toBeCloseTo(90);
        expect(cell.idle * 3600).toBeCloseTo(30);
        expect(cell.distinctDates).toBe(1);
        expect(result.heatmap.cells.filter(cell => cell.observed > 0)).toHaveLength(1);
    });

    it('counts unknown heatmap evidence and distinguishes retained names from current registrations', async () => {
        const { recordMetrics, readMetrics } = await import('../../src/lib/server/fleet/metrics.js');
        const { db } = await import('../../src/lib/server/db/index.js');
        const at = Date.UTC(2026, 0, 3, 12);
        const sample = { server: 'reused', game: 't5', map: 'Moon', players: null, capacity: null };
        recordMetrics([sample, { ...sample, server: 'removed' }, { ...sample, server: 'tombstone' }], at);
        // A newly registered name can link to the current server without asserting
        // that its earlier historical observations belong to this registration.
        db().prepare('INSERT INTO servers (name, created_at) VALUES (?, ?)').run('reused', new Date(at + 15_000).toISOString());
        db().prepare('INSERT INTO servers (name, destroyed_at) VALUES (?, ?)').run('tombstone', new Date(at).toISOString());
        const result = readMetrics(1, at + 30_000);
        expect(result.servers.find(server => server.server === 'reused')!.currentRegistered).toBe(true);
        expect(result.servers.filter(server => server.server !== 'reused').every(server => !server.currentRegistered)).toBe(true);
        expect(result.heatmap.cells.reduce((sum, cell) => sum + cell.unknown, 0) * 3600).toBeCloseTo(90);
        expect(result.heatmap.cells.reduce((sum, cell) => sum + cell.observed, 0)).toBe(0);
        expect(result.heatmap.cells.find(cell => cell.unknown > 0)!.distinctDates).toBe(1);
    });
});