import { describe, it, expect, vi, beforeEach, afterEach } from 'vitest';
import { EventEmitter } from 'events';
import fs from 'fs';
import os from 'os';
import path from 'path';
import { HookManager, shouldAutoLoadPid } from '../src/hook-manager';
import { PipeWatcher } from '../src/pipe-watcher';
import type { HookInjectResult, ManualMapHandle } from '../src/injector';
import type { BridgeManagerSink } from '../src/hook-manager';
import type { AccountLoginState } from '../src/qq-account';
import type { QqHookClient } from '../src/qq-hook-client';
import {
    createLogger,
    getLogLevel,
    setLogLevel,
    subscribeLogs,
    type LogEntry,
} from '@snowluma/common/logger';

const DUMMY_HANDLE: ManualMapHandle = { base: 0n, entry: 0n, exceptionTable: 0n, size: 0 };
const flush = () => new Promise<void>((r) => setImmediate(r));
const previousLogLevel = getLogLevel();

function managerTrace(entries: LogEntry[]): LogEntry[] {
    return entries.filter((entry) => entry.level === 'trace' && entry.scope === 'Hook');
}

function makeManager(opts: {
    autoLoadOnDiscovery?: boolean;
    processes?: number[];
    onSessionsChanged?: () => void;
    inject?: (pid: number) => Promise<HookInjectResult>;
    detectAccounts?: (pids: readonly number[]) => Promise<AccountLoginState[]>;
}) {
    let pids = opts.processes ?? [];
    const live = new Set<number>();
    const inject = vi.fn(
        opts.inject ??
            (async () => ({
                method: 'loadModuleManual' as const,
                handle: DUMMY_HANDLE,
            })),
    );
    const unload = vi.fn(async () => {});
    const pipeWatcher = new PipeWatcher({
        listProcesses: async () => pids.map((pid) => ({ pid, name: 'qq', path: '' })),
        listLivePipes: async () => new Set(live),
        intervalMs: 60_000, // disable internal timer; tests drive ticks manually
    });
    // FakeClient — never connected; just needs to satisfy EventEmitter +
    // a minimal subset of QqHookClient for HookSession.tearDownClient().
    const makeClient = vi.fn(() => {
        const c = new EventEmitter() as EventEmitter & Partial<QqHookClient>;
        (c as any).isClosed = false;
        (c as any).isLoggedIn = false;
        (c as any).getLoginState = () => ({ loggedIn: false, uin: '0', uinNumber: 0n });

        (c as any).connectAll = async () => {
            throw new Error('test: never really connect');
        };

        (c as any).close = () => {
            (c as any).isClosed = true;
        };

        return c as unknown as QqHookClient;
    });
    const bridgeManager = {
        onPacket: vi.fn(),
        onHookLogin: vi.fn(),
        onPidDisconnected: vi.fn(),
    } as unknown as BridgeManagerSink;
    const manager = new HookManager({
        bridgeManager,
        pipeWatcher,
        injector: { inject, unload },
        makeClient,
        autoLoadOnDiscovery: opts.autoLoadOnDiscovery,
        onSessionsChanged: opts.onSessionsChanged,
        listProcesses: async () => pids.map((pid) => ({ pid, name: 'qq', path: '' })),
        // Detection reads QQ's own data directories; tests stay off the host.
        detectAccounts: opts.detectAccounts ?? (async () => []),
        watchAccounts: () => () => {},
    });
    return {
        manager,
        inject,
        pipeWatcher,
        setProcesses: (next: number[]) => {
            pids = next;
        },
    };
}

afterEach(() => {
    setLogLevel(previousLogLevel);
});

describe('HookManager runtime TRACE', () => {
    it('records discovery and process-gone facts while unchanged ticks stay silent', async () => {
        const entries: LogEntry[] = [];
        const sessionsChanged = vi.fn();
        setLogLevel('trace');
        const unsubscribe = subscribeLogs((entry) => entries.push(entry));
        const ctx = makeManager({
            autoLoadOnDiscovery: false,
            processes: [],
            onSessionsChanged: sessionsChanged,
        });

        try {
            await ctx.pipeWatcher.start();
            const baseline = managerTrace(entries).length;
            await ctx.pipeWatcher.tickNow();
            await ctx.pipeWatcher.tickNow();
            expect(managerTrace(entries)).toHaveLength(baseline);

            ctx.setProcesses([4242]);
            await ctx.pipeWatcher.tickNow();
            ctx.setProcesses([]);
            await ctx.pipeWatcher.tickNow();
            await flush();

            const facts = managerTrace(entries).filter((entry) =>
                entry.message.startsWith('hook_manager_fact '),
            );
            expect(facts.map((entry) => entry.message)).toEqual([
                expect.stringContaining('hook_manager_fact event=process_discovered pid=4242'),
                'hook_manager_fact event=process_gone pid=4242 tracked=true',
            ]);
            expect(facts.every((entry) => entry.req !== undefined)).toBe(true);
        } finally {
            unsubscribe();
            ctx.manager.dispose();
        }
    });

    it('records bounded transient retries and recovery as separate attempts', async () => {
        const entries: LogEntry[] = [];
        setLogLevel('trace');
        const unsubscribe = subscribeLogs((entry) => entries.push(entry));
        const ctx = makeManager({ autoLoadOnDiscovery: true, processes: [4242] });
        ctx.inject
            .mockImplementationOnce(() => {
                throw new Error(
                    'target process does not map /lib/x86_64-linux-gnu/libc.so.6 while resolving mmap',
                );
            })
            .mockImplementationOnce(() => ({
                method: 'loadModuleManual' as const,
                handle: DUMMY_HANDLE,
            }));

        try {
            await ctx.pipeWatcher.start();
            await flush();
            await flush();
            await ctx.pipeWatcher.tickNow();
            await flush();
            await flush();

            const attempts = managerTrace(entries).filter((entry) =>
                entry.message.startsWith('hook_autoload_'),
            );
            expect(attempts.map((entry) => entry.message)).toEqual([
                'hook_autoload_start pid=4242 attempt=1 maxAttempts=3',
                expect.stringMatching(
                    /^hook_autoload_terminal pid=4242 attempt=1 outcome=failed reason=retry_pending error=.*elapsedMs=\d+$/,
                ),
                'hook_autoload_start pid=4242 attempt=2 maxAttempts=3',
                expect.stringMatching(
                    /^hook_autoload_terminal pid=4242 attempt=2 outcome=completed reason=recovered state=.*elapsedMs=\d+$/,
                ),
            ]);
            expect(attempts[0]!.req).toBe(attempts[1]!.req);
            expect(attempts[2]!.req).toBe(attempts[3]!.req);
            expect(attempts[0]!.req).not.toBe(attempts[2]!.req);
        } finally {
            unsubscribe();
            ctx.manager.dispose();
        }
    });

    it('ends an in-flight auto-load as dropped when a manual load supersedes it', async () => {
        const entries: LogEntry[] = [];
        let resolveInjection!: (result: HookInjectResult) => void;
        const injection = new Promise<HookInjectResult>((resolve) => {
            resolveInjection = resolve;
        });
        setLogLevel('trace');
        const unsubscribe = subscribeLogs((entry) => entries.push(entry));
        const ctx = makeManager({
            autoLoadOnDiscovery: true,
            processes: [4242],
            inject: () => injection,
        });

        try {
            await ctx.pipeWatcher.start();
            await flush();
            const manualLoad = ctx.manager.loadProcess(4242);
            resolveInjection({ method: 'loadModuleManual', handle: DUMMY_HANDLE });
            await manualLoad;
            await flush();

            const attempts = managerTrace(entries).filter((entry) =>
                entry.message.startsWith('hook_autoload_'),
            );
            expect(attempts.map((entry) => entry.message)).toEqual([
                'hook_autoload_start pid=4242 attempt=1 maxAttempts=3',
                expect.stringMatching(
                    /^hook_autoload_terminal pid=4242 attempt=1 outcome=dropped reason=superseded elapsedMs=\d+$/,
                ),
            ]);
            expect(attempts[0]!.req).toBe(attempts[1]!.req);
        } finally {
            unsubscribe();
            ctx.manager.dispose();
        }
    });

    it.each([
        {
            name: 'permanent failure',
            error: 'ptrace denied',
            ticks: 1,
            attempts: 1,
            reason: 'permanent_failure',
        },
        {
            name: 'retry exhaustion',
            error: 'target process does not map /lib/libc.so.6 while resolving mmap',
            ticks: 4,
            attempts: 3,
            reason: 'retry_exhausted',
        },
    ])('records $name terminal', async ({ error, ticks, attempts, reason }) => {
        const entries: LogEntry[] = [];
        setLogLevel('trace');
        const unsubscribe = subscribeLogs((entry) => entries.push(entry));
        const ctx = makeManager({ autoLoadOnDiscovery: true, processes: [4242] });
        ctx.inject.mockImplementation(() => {
            throw new Error(error);
        });

        try {
            await ctx.pipeWatcher.start();
            await flush();
            await flush();

            for (let tick = 0; tick < ticks; tick += 1) {
                await ctx.pipeWatcher.tickNow();
                await flush();
                await flush();
            }

            const starts = managerTrace(entries).filter((entry) =>
                entry.message.startsWith('hook_autoload_start '),
            );
            const terminals = managerTrace(entries).filter((entry) =>
                entry.message.startsWith('hook_autoload_terminal '),
            );
            expect(starts).toHaveLength(attempts);
            expect(terminals).toHaveLength(attempts);
            expect(terminals.at(-1)!.message).toContain(`reason=${reason}`);
        } finally {
            unsubscribe();
            ctx.manager.dispose();
        }
    });
});

describe('HookManager.autoLoadOnDiscovery', () => {
    it('does NOT inject on process-discovered when flag is off', async () => {
        const ctx = makeManager({ autoLoadOnDiscovery: false, processes: [4242] });
        await ctx.pipeWatcher.start();
        await flush();
        expect(ctx.inject).not.toHaveBeenCalled();
        ctx.manager.dispose();
    });

    it('injects every newly-discovered PID when flag is on', async () => {
        const ctx = makeManager({ autoLoadOnDiscovery: true, processes: [4242] });
        await ctx.pipeWatcher.start();
        // session.load() is queued via a per-session promise chain; flush twice
        // so the auto-load runs to completion before we assert.
        await flush();
        await flush();
        expect(ctx.inject).toHaveBeenCalledTimes(1);
        expect(ctx.inject).toHaveBeenCalledWith(4242);

        // A second PID appearing mid-flight should also trigger an inject.
        ctx.setProcesses([4242, 9999]);
        await ctx.pipeWatcher.tickNow();
        await flush();
        await flush();
        expect(ctx.inject).toHaveBeenCalledTimes(2);
        expect(ctx.inject).toHaveBeenLastCalledWith(9999);

        ctx.manager.dispose();
    });

    it('swallows inject errors so the watcher keeps running', async () => {
        const ctx = makeManager({ autoLoadOnDiscovery: true, processes: [4242] });
        ctx.inject.mockImplementationOnce(() => {
            throw new Error('ptrace denied');
        });
        await ctx.pipeWatcher.start();
        await flush();
        await flush();

        // Second PID should still be auto-loaded — the failure on 4242 must
        // not leak out of the listener and break the watcher's emit loop.
        ctx.setProcesses([4242, 9999]);
        await ctx.pipeWatcher.tickNow();
        await flush();
        await flush();
        expect(ctx.inject).toHaveBeenCalledTimes(2);

        ctx.manager.dispose();
    });

    it('retries a transient libc mapping failure on the next watcher tick', async () => {
        const ctx = makeManager({ autoLoadOnDiscovery: true, processes: [4242] });
        ctx.inject.mockImplementationOnce(() => {
            throw new Error(
                'target process does not map /lib/x86_64-linux-gnu/libc.so.6 while resolving mmap',
            );
        });

        await ctx.pipeWatcher.start();
        await flush();
        await flush();
        expect(ctx.inject).toHaveBeenCalledTimes(1);

        await ctx.pipeWatcher.tickNow();
        await flush();
        await flush();
        expect(ctx.inject).toHaveBeenCalledTimes(2);
        expect(ctx.inject).toHaveBeenLastCalledWith(4242);

        ctx.manager.dispose();
    });

    it('does not retry permanent auto-load errors', async () => {
        const ctx = makeManager({ autoLoadOnDiscovery: true, processes: [4242] });
        ctx.inject.mockImplementation(() => {
            throw new Error('ptrace denied');
        });

        await ctx.pipeWatcher.start();
        await flush();
        await flush();

        await ctx.pipeWatcher.tickNow();
        await flush();
        await flush();
        expect(ctx.inject).toHaveBeenCalledTimes(1);

        ctx.manager.dispose();
    });

    it('stops retrying a transient libc mapping failure after three attempts', async () => {
        const ctx = makeManager({ autoLoadOnDiscovery: true, processes: [4242] });
        ctx.inject.mockImplementation(() => {
            throw new Error(
                'target process does not map /lib/x86_64-linux-gnu/libc.so.6 while resolving mmap',
            );
        });

        await ctx.pipeWatcher.start();
        await flush();
        await flush();

        for (let tick = 0; tick < 4; tick += 1) {
            await ctx.pipeWatcher.tickNow();
            await flush();
            await flush();
        }

        expect(ctx.inject).toHaveBeenCalledTimes(3);

        ctx.manager.dispose();
    });
});

// `shouldAutoLoadPid` reads /proc/<pid>/cmdline directly, so we point
// it at a temporary directory that mimics the procfs layout. This lets
// the tests run on macOS / CI without a live Linux QQ process.
describe('shouldAutoLoadPid', () => {
    let tmpProc: string;
    const originalReadFileSync = fs.readFileSync;
    const log = createLogger('test');
    const originalPlatform = process.platform;
    const originalAutoLoadAll = process.env.SNOWLUMA_HOOK_AUTOLOAD_ALL;

    beforeEach(() => {
        tmpProc = fs.mkdtempSync(path.join(os.tmpdir(), 'hookmgr-proc-'));
        Object.defineProperty(process, 'platform', { value: 'linux', configurable: true });
        delete process.env.SNOWLUMA_HOOK_AUTOLOAD_ALL;
        // Redirect readFileSync('/proc/<pid>/cmdline') to the tmp dir.
        (fs.readFileSync as unknown as typeof fs.readFileSync) = ((
            p: string,
            ...rest: unknown[]
        ) => {
            const match = /^\/proc\/(\d+)\/cmdline$/.exec(p);

            if (match) {
                return originalReadFileSync(
                    path.join(tmpProc, match[1], 'cmdline'),
                    ...(rest as [BufferEncoding]),
                );
            }

            return originalReadFileSync(p, ...(rest as [BufferEncoding]));
        }) as typeof fs.readFileSync;
    });

    afterEach(() => {
        (fs.readFileSync as unknown as typeof fs.readFileSync) = originalReadFileSync;
        Object.defineProperty(process, 'platform', { value: originalPlatform, configurable: true });

        if (originalAutoLoadAll === undefined) {
            delete process.env.SNOWLUMA_HOOK_AUTOLOAD_ALL;
        } else {
            process.env.SNOWLUMA_HOOK_AUTOLOAD_ALL = originalAutoLoadAll;
        }

        fs.rmSync(tmpProc, { recursive: true, force: true });
    });

    function writeCmdline(pid: number, args: string[]): void {
        const dir = path.join(tmpProc, String(pid));
        fs.mkdirSync(dir, { recursive: true });
        fs.writeFileSync(path.join(dir, 'cmdline'), args.join('\0') + '\0');
    }

    it('allows the QQ main process (no --type=)', () => {
        writeCmdline(50, ['qq', '--no-sandbox']);
        expect(shouldAutoLoadPid(50, log)).toBe(true);
    });

    it('rejects Electron zygotes', () => {
        writeCmdline(59, ['/opt/QQ/qq', '--type=zygote', '--no-zygote-sandbox', '--no-sandbox']);
        expect(shouldAutoLoadPid(59, log)).toBe(false);
    });

    it('rejects renderer/gpu/utility children', () => {
        writeCmdline(70, ['/opt/QQ/qq', '--type=renderer']);
        writeCmdline(71, ['/opt/QQ/qq', '--type=gpu-process']);
        writeCmdline(72, [
            '/opt/QQ/qq',
            '--type=utility',
            '--utility-sub-type=network.mojom.NetworkService',
        ]);
        expect(shouldAutoLoadPid(70, log)).toBe(false);
        expect(shouldAutoLoadPid(71, log)).toBe(false);
        expect(shouldAutoLoadPid(72, log)).toBe(false);
    });

    it('allows everything if SNOWLUMA_HOOK_AUTOLOAD_ALL=1 (escape hatch)', () => {
        writeCmdline(59, ['/opt/QQ/qq', '--type=zygote']);
        process.env.SNOWLUMA_HOOK_AUTOLOAD_ALL = '1';
        expect(shouldAutoLoadPid(59, log)).toBe(true);
    });

    it('allows on non-linux platforms (filter is a Linux-only workaround)', () => {
        Object.defineProperty(process, 'platform', { value: 'win32', configurable: true });
        // No cmdline file needed — we return true before touching procfs.
        expect(shouldAutoLoadPid(59, log)).toBe(true);
    });

    it('allows when /proc is unreadable (dead PID, permission issue)', () => {
        expect(shouldAutoLoadPid(99999, log)).toBe(true);
    });
});

describe('HookManager — signed-in account labelling', () => {
    it('labels each process with the account detected on it', async () => {
        const ctx = makeManager({
            processes: [4242, 5151],
            detectAccounts: async () => [
                { uin: '10001', uid: 'u_a', nickname: 'Alice', pid: 4242 },
                { uin: '10002', uid: 'u_b', nickname: 'Bob', pid: null },
            ],
        });

        try {
            const list = await ctx.manager.listProcesses();
            expect(list.map((info) => [info.pid, info.account])).toEqual([
                [4242, { uin: '10001', nickname: 'Alice' }],
                [5151, null],
            ]);
        } finally {
            ctx.manager.dispose();
        }
    });

    it('leaves processes unlabelled when detection fails', async () => {
        const ctx = makeManager({
            processes: [4242],
            detectAccounts: async () => {
                throw new Error('login.db unreadable');
            },
        });

        try {
            const list = await ctx.manager.listProcesses();
            expect(list[0]!.account).toBeNull();
        } finally {
            ctx.manager.dispose();
        }
    });
});