import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest';
import { appendFile, mkdir, rm, utimes, writeFile } from 'node:fs/promises';
import { join } from 'node:path';
import { newFixture, type Fixture } from '../helpers/fixture.js';
import { gameEvent } from '../helpers/telemetry.js';
import type { GameEvent } from '../../src/lib/telemetry.js';
import type { ContextualChatEntry } from '../../src/lib/game-chat.js';

type ChatMessageEntry = Extract<ContextualChatEntry, { type: 'message' }>;

const SERVER = 't5_zombie_theater_1';
const T6_SERVER = 't6_zombie_town_1';
let fixture: Fixture;
let baseline: number;
const at = (seconds: number) => new Date(baseline + seconds * 1000).toISOString();

beforeEach(async () => {
    vi.resetModules();
    vi.useFakeTimers({ toFake: ['Date'] });
    baseline = Math.floor(Date.now() / 1000) * 1000 - 600_000;
    fixture = await newFixture([SERVER, T6_SERVER]);
    const { seedServerRegistry } = await import('../../src/lib/server/fleet/servers.js');
    const { db } = await import('../../src/lib/server/db/index.js');
    await seedServerRegistry();
    db().prepare('UPDATE servers SET created_at = ?').run(at(-120));
});

afterEach(async () => {
    vi.restoreAllMocks();
    vi.useRealTimers();
    await fixture.cleanup();
});

async function log(lines: string[], lastWrite = 60, server = SERVER, filename?: string) {
    const folder = join(server.startsWith('t6_') ? fixture.t6 : fixture.t5, server, 'logs');
    await mkdir(folder, { recursive: true });
    const path = join(
        folder,
        filename ?? (server.startsWith('t6_') ? 'games_zm.log' : 'games_sp.log')
    );
    await writeFile(path, lines.join('\n') + '\n');
    await utimes(path, new Date(at(lastWrite)), new Date(at(lastWrite)));
}

async function report(
    event: GameEvent['event'],
    seconds: number,
    round = 1,
    status = 200,
    diagnostic = true
) {
    const value = gameEvent(event, round, 1, SERVER);
    if (status === 200) {
        const { saveTelemetry } = await import('../../src/lib/server/fleet/telemetry.js');
        saveTelemetry({ ...value, receivedAt: at(seconds) });
    }
    if (diagnostic) {
        const { recordTelemetryRequest } =
            await import('../../src/lib/server/fleet/telemetry-requests.js');
        recordTelemetryRequest({
            value,
            receivedAt: at(seconds),
            status,
            error: status === 200 ? null : 'Rejected request',
            contentType: 'application/json'
        });
    }
}

async function get(server = SERVER) {
    const { GET } = await import('../../src/routes/api/servers/[name]/chat/+server.js');
    return GET({ params: { name: server } });
}

function advanceTime(milliseconds = 15_000) {
    vi.setSystemTime(Date.now() + milliseconds);
}

describe('server chat API', () => {
    it('buffers partial UTF-8 lines and avoids context queries when the log is unchanged', async () => {
        await report('game_start', 0);
        await report('heartbeat', 40, 4);
        await log(['60:50 say;abc;0;Player;first'], 50);
        expect((await (await get()).json()).entries).toHaveLength(1);
        const { db } = await import('../../src/lib/server/db/index.js');
        const prepare = vi.spyOn(db(), 'prepare');
        advanceTime();
        await get();
        expect(prepare.mock.calls.some(([sql]) => sql.includes('FROM telemetry_requests'))).toBe(
            false
        );
        expect(
            prepare.mock.calls.some(([sql]) => sql.includes('last_received_at AS lastReceivedAt'))
        ).toBe(false);
        prepare.mockRestore();
        const path = join(fixture.t5, SERVER, 'logs/games_sp.log');
        const line = Buffer.from('61:00 say;abc;0;Player;café\n');
        await appendFile(path, line.subarray(0, -2)); // Split inside é, before the newline.
        await utimes(path, new Date(at(60)), new Date(at(60)));
        advanceTime();
        expect((await (await get()).json()).entries).toHaveLength(1);
        await appendFile(path, line.subarray(-2));
        await utimes(path, new Date(at(60)), new Date(at(60)));
        advanceTime();
        const body = await (await get()).json();
        expect(body.entries.map((entry: ChatMessageEntry) => entry.message.message)).toEqual([
            'first',
            'café'
        ]);
        expect(body.entries[1].context.realTime).toBe(at(60));
        expect((await (await get()).json()).entries).toEqual(body.entries);
    });

    it('retries appended bytes if archiving fails before publishing the cursor', async () => {
        await report('game_start', 0);
        await report('heartbeat', 40, 4);
        await log(['60:50 say;abc;0;Player;first'], 50);
        await get();
        const path = join(fixture.t5, SERVER, 'logs/games_sp.log');
        await appendFile(path, '61:00 say;abc;0;Player;retry me\n');
        await utimes(path, new Date(at(60)), new Date(at(60)));
        advanceTime();
        const { db } = await import('../../src/lib/server/db/index.js');
        const handle = db(),
            original = handle.prepare.bind(handle);
        const prepare = vi.spyOn(handle, 'prepare').mockImplementation((sql: string) => {
            if (sql.includes('INSERT INTO match_chat'))
                throw new Error('Temporary database failure');
            return original(sql);
        });
        vi.spyOn(console, 'error').mockImplementation(() => {});
        expect((await get()).status).toBe(500);
        prepare.mockRestore();
        advanceTime();
        expect(
            (await (await get()).json()).entries.map(
                (entry: ChatMessageEntry) => entry.message.message
            )
        ).toEqual(['first', 'retry me']);
    });

    it('skips empty, stopped and offline servers and collects one last time after players leave', async () => {
        const { db } = await import('../../src/lib/server/db/index.js');
        const { createHost } = await import('../../src/lib/server/hosts/index.js');
        const logs = await import('../../src/lib/server/fleet/logs.js');
        const read = vi.spyOn(logs, 'readLogChunk');
        const { collectFleetChat } = await import('../../src/lib/server/fleet/chat.js');
        db().prepare("UPDATE servers SET last_players=0,container_state='running'").run();
        await collectFleetChat();
        expect(read).not.toHaveBeenCalled();
        db().prepare('UPDATE servers SET last_players=1 WHERE name=?').run(SERVER);
        await log(['60:50 say;abc;0;Player;playing'], 50);
        await collectFleetChat();
        expect(read).toHaveBeenCalledTimes(1);
        db().prepare('UPDATE servers SET last_players=0 WHERE name=?').run(SERVER);
        await log(['60:50 say;abc;0;Player;playing', '61:00 say;abc;0;Player;goodbye']);
        expect((await (await get()).json()).entries).toHaveLength(1);
        expect(read).toHaveBeenCalledTimes(1);
        await collectFleetChat();
        await collectFleetChat();
        expect(read).toHaveBeenCalledTimes(2);
        expect((await (await get()).json()).entries).toHaveLength(2);
        expect(read).toHaveBeenCalledTimes(2);
        db()
            .prepare("UPDATE servers SET last_players=1,container_state='stopped' WHERE name=?")
            .run(SERVER);
        await collectFleetChat();
        expect(read).toHaveBeenCalledTimes(2);
        const host = createHost({ name: 'Offline' });
        db().prepare("UPDATE servers SET container_state='running' WHERE name=?").run(SERVER);
        db()
            .prepare(
                `INSERT INTO native_instances(id,server,host_id,library_id,image,port,created_at)
            VALUES('offline-instance',?,?,'library','image',28960,?)`
            )
            .run(SERVER, host.id, at(0));
        await collectFleetChat();
        expect(read).toHaveBeenCalledTimes(2);
    });

    it('keeps real timestamps and historical match context stable across refreshes', async () => {
        await report('game_start', 0);
        await report('round_change', 40, 4);
        await report('round_change', 45, 99, 400);
        await log(['60:50 say;abc;0;Player;hello', '61:00 J;abc;0;Player']);
        const response = await get();
        const body = await response.json();
        expect(response.status).toBe(200);
        expect(response.headers.get('cache-control')).toBe('no-store');
        expect(body).toMatchObject({
            ok: true,
            missing: false,
            entries: [
                {
                    type: 'message',
                    message: { player: 'Player', message: 'hello' },
                    context: { realTime: at(50), matchElapsedMs: 50_000, round: 4 }
                }
            ]
        });
        expect(JSON.stringify(body)).not.toContain('headshots');
        vi.spyOn(Date, 'now').mockReturnValue(baseline + 900_000);
        expect(await (await get()).json()).toEqual(body);
    });

    it('reads the correct game log for each game', async () => {
        await log(['1:00 say;abc;0;T5 player;t5 message']);
        await log(['1:00 say;abc;0;Wrong;wrong t5 file'], 60, SERVER, 'games_zm.log');
        await log(['1:00 say;abc;0;T6 player;t6 message'], 60, T6_SERVER);
        await log(['1:00 say;abc;0;Wrong;wrong t6 file'], 60, T6_SERVER, 'games_sp.log');
        expect((await (await get()).json()).entries[0].message.message).toBe('t5 message');
        expect((await (await get(T6_SERVER)).json()).entries[0].message.message).toBe('t6 message');
    });

    it('returns an empty successful response until the game log exists', async () => {
        expect(await (await get()).json()).toEqual({ ok: true, entries: [], missing: true });
    });

    it('rejects unknown and destroyed servers even when files remain', async () => {
        expect((await get('t5_zombie_theater_99')).status).toBe(404);
        await log(['1:00 say;abc;0;Player;hello']);
        const { db } = await import('../../src/lib/server/db/index.js');
        db().prepare('UPDATE servers SET destroyed_at = ? WHERE name = ?').run(at(60), SERVER);
        expect((await get()).status).toBe(404);
    });

    it('rejects registered names that escape the server directory', async () => {
        const { db } = await import('../../src/lib/server/db/index.js');
        db().prepare('INSERT INTO servers (name) VALUES (?)').run('..');
        expect((await get('..')).status).toBe(400);
    });

    it('reports read failures without returning server filesystem paths', async () => {
        const logs = await import('../../src/lib/server/fleet/logs.js');
        vi.spyOn(logs, 'readLogChunk').mockRejectedValue(
            new Error('read failed at /private/server/log')
        );
        vi.spyOn(console, 'error').mockImplementation(() => {});
        const response = await get();
        expect(response.status).toBe(500);
        expect(await response.json()).toEqual({ ok: false, reason: 'Could not read server chat' });
    });

    it('keeps latest accepted gameplay available when diagnostic logging was unavailable', async () => {
        await report('game_start', 0, 1, 200, false);
        await report('heartbeat', 40, 1, 200, false);
        await log(['60:50 say;abc;0;Player;first round', '61:00 J;abc;0;Player']);
        const body = await (await get()).json();
        expect(body.entries).toHaveLength(1);
        expect(body.entries[0].context).toEqual({
            realTime: at(50),
            matchElapsedMs: 50_000,
            round: 1
        });
    });

    it('does not reuse round diagnostics after their retention window', async () => {
        await report('game_start', 0);
        await report('heartbeat', 40, 4);
        await log(['60:50 say;abc;0;Player;older message', '61:00 J;abc;0;Player']);
        vi.spyOn(Date, 'now').mockReturnValue(baseline + 8 * 86_400_000);
        const body = await (await get()).json();
        expect(body.entries[0].context).toEqual({
            realTime: at(50),
            matchElapsedMs: 50_000,
            round: null
        });
    });

    it('does not associate retained messages with a deleted server incarnation', async () => {
        await report('game_start', 0);
        await report('heartbeat', 40, 8);
        const { db } = await import('../../src/lib/server/db/index.js');
        db().prepare('DELETE FROM servers WHERE name = ?').run(SERVER);
        db()
            .prepare(
                `INSERT INTO servers (name, game, map, created_at)
            VALUES (?, 't5', 'zombie_theater', ?)`
            )
            .run(SERVER, at(70));
        await report('game_start', 80);
        await report('heartbeat', 90, 2);
        await log(
            ['60:50 say;abc;0;Player;previous server', '61:40 say;abc;0;Player;current server'],
            100
        );
        const body = await (await get()).json();
        const messages = body.entries.filter((entry: { type: string }) => entry.type === 'message');
        expect(messages).toHaveLength(1);
        expect(messages[0].message.message).toBe('current server');
        expect(messages[0].context).toEqual({
            realTime: at(100),
            matchElapsedMs: 20_000,
            round: 2
        });
    });

    it('clears at a new match before it writes to the log and keeps the old chat with its match', async () => {
        const logs = await import('../../src/lib/server/fleet/logs.js');
        const read = vi.spyOn(logs, 'readLogChunk');
        await report('game_start', 0);
        await report('round_change', 20, 4);
        await log(['60:30 say;abc;0;Player;old match'], 30);
        expect((await (await get()).json()).entries[0].message.message).toBe('old match');
        await report('game_end', 60, 4);
        await report('game_start', 80);
        expect((await (await get()).json()).entries).toEqual([]);
        expect(read).toHaveBeenCalledTimes(1);
        await report('heartbeat', 90, 2);
        await log(['60:30 say;abc;0;Player;old match', '61:40 say;abc;0;Player;new match'], 100);
        advanceTime();
        const body = await (await get()).json();
        expect(body.entries.map((entry: ChatMessageEntry) => entry.message.message)).toEqual([
            'new match'
        ]);
        const { getMatchDetail } = await import('../../src/lib/server/fleet/match-history.js');
        expect(
            getMatchDetail(1)!.chat.map(
                (entry) => entry.type === 'message' && entry.message.message
            )
        ).toEqual(['old match']);
    });

    it('clears on log boundaries and clock resets before the next telemetry report', async () => {
        for (const boundary of [
            '61:00 InitGame:',
            '0:00 InitGame:',
            '0:00 J;abc;0;Player',
            'InitGame:'
        ]) {
            await report('game_start', 0);
            await report('heartbeat', 20, 4);
            await log(['60:30 say;abc;0;Player;old match'], 30);
            advanceTime();
            expect((await (await get()).json()).entries).toHaveLength(1);
            await log(['60:30 say;abc;0;Player;old match', boundary], 60);
            advanceTime();
            expect((await (await get()).json()).entries, boundary).toEqual([]);
        }
    });

    it('shows only the latest log session without telemetry', async () => {
        await log(
            [
                '80:00 say;abc;0;Player;old match',
                '0:00 InitGame:',
                '0:30 say;abc;0;Player;new match'
            ],
            60
        );
        const entries = (await (await get()).json()).entries;
        expect(
            entries
                .filter((entry: ContextualChatEntry) => entry.type === 'message')
                .map((entry: ChatMessageEntry) => entry.message.message)
        ).toEqual(['new match']);
        await log(['80:00 say;abc;0;Player;old match', '0:00 InitGame:'], 60);
        advanceTime();
        expect(
            (await (await get()).json()).entries.some(
                (entry: ContextualChatEntry) => entry.type === 'message'
            )
        ).toBe(false);
    });

    it('collects without a viewer and retains repeated messages after log rotation, restart and server deletion', async () => {
        await report('game_start', 0);
        await report('heartbeat', 20, 4);
        const lines = ['60:30 say;abc;0;Player;hello', '60:30 say;abc;0;Player;hello'];
        await log(lines, 30);
        const { collectFleetChat } = await import('../../src/lib/server/fleet/chat.js');
        await collectFleetChat();
        await collectFleetChat();
        await report('game_end', 60, 4);
        await log([...lines, '61:00 ExitLevel:'], 60);
        await collectFleetChat();
        const { closeDb, db } = await import('../../src/lib/server/db/index.js');
        const { getMatchDetail } = await import('../../src/lib/server/fleet/match-history.js');
        const saved = getMatchDetail(1)!.chat;
        expect(saved).toHaveLength(2);
        expect(saved[0]).toMatchObject({
            message: { message: 'hello' },
            context: { realTime: at(30), round: 4 }
        });
        await rm(join(fixture.t5, SERVER, 'logs'), { recursive: true });
        closeDb();
        expect((await (await get()).json()).entries).toEqual(saved);
        db().prepare('DELETE FROM servers WHERE name = ?').run(SERVER);
        expect(getMatchDetail(1)!.chat).toEqual(saved);
        // Match retention also removes its chat, with no orphaned history.
        db().prepare('DELETE FROM leaderboard_matches WHERE id = 1').run();
        expect(db().prepare('SELECT * FROM match_chat').all()).toEqual([]);
    });
});