import { getLogLevel, setLogLevel, subscribeLogs, type LogEntry } from '@snowluma/common/logger';
import { afterEach, describe, expect, it, vi } from 'vitest';
import { traceAuthenticatedWebuiMutation } from '../src/webui/mutation-trace';

const previousLogLevel = getLogLevel();

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

async function waitForTerminal(entries: LogEntry[]): Promise<LogEntry[]> {
    await vi.waitFor(() => {
        expect(
            mutationTrace(entries).some((entry) =>
                entry.message.startsWith('webui_mutation_terminal '),
            ),
        ).toBe(true);
    });
    return mutationTrace(entries);
}

describe('traceAuthenticatedWebuiMutation', () => {
    afterEach(() => {
        setLogLevel(previousLogLevel);
    });

    it('traces a successful JSON write with complete request and response data', async () => {
        const entries: LogEntry[] = [];
        setLogLevel('trace');
        const unsubscribe = subscribeLogs((entry) => entries.push(entry));
        const requestBody = '{"logLevel":"trace"}';
        const responseBody = '{"success":true}';
        const request = new Request('http://127.0.0.1/api/system/settings?source=test', {
            method: 'POST',
            headers: {
                authorization: 'Bearer exact-token',
                'content-type': 'application/json',
                'x-request-detail': 'complete',
            },
            body: requestBody,
        });

        try {
            const response = await traceAuthenticatedWebuiMutation(
                request,
                async () =>
                    new Response(responseBody, {
                        status: 201,
                        headers: {
                            'content-type': 'application/json',
                            'x-response-detail': 'complete',
                        },
                    }),
            );

            expect(response.status).toBe(201);
            expect(await response.text()).toBe(responseBody);

            const trace = await waitForTerminal(entries);
            expect(trace).toHaveLength(4);
            expect(trace[0]!.message).toContain('webui_mutation_start method="POST"');
            expect(trace[0]!.message).toContain(
                'url="http://127.0.0.1/api/system/settings?source=test"',
            );
            expect(trace[0]!.message).toContain('authorization');
            expect(trace[0]!.message).toContain('Bearer exact-token');
            expect(trace[0]!.message).toContain('x-request-detail');
            expect(trace[1]!.message).toContain('branch=request_body');
            expect(trace[1]!.message).toContain(`text=${JSON.stringify(requestBody)}`);
            expect(trace[1]!.message).toContain(`body=${Buffer.from(requestBody).toString('hex')}`);
            expect(trace[2]!.message).toContain('branch=response status=201');
            expect(trace[2]!.message).toContain('x-response-detail');
            expect(trace[2]!.message).toContain(`text=${JSON.stringify(responseBody)}`);
            expect(trace[2]!.message).toContain(
                `body=${Buffer.from(responseBody).toString('hex')}`,
            );
            expect(trace[3]!.message).toMatch(
                /^webui_mutation_terminal outcome=completed reason=response_completed status=201 elapsedMs=\d+$/,
            );
            expect(trace.every((entry) => entry.req === trace[0]!.req)).toBe(true);
            expect(trace[0]!.req).toEqual(expect.any(Number));
        } finally {
            unsubscribe();
        }
    });

    it('traces non-2xx and binary bodies without consuming the response', async () => {
        const entries: LogEntry[] = [];
        setLogLevel('trace');
        const unsubscribe = subscribeLogs((entry) => entries.push(entry));
        const requestBytes = Uint8Array.from([0x00, 0xff, 0x80, 0x41]);
        const responseBytes = Uint8Array.from([0xde, 0xad, 0xbe, 0xef, 0x00]);

        try {
            const response = await traceAuthenticatedWebuiMutation(
                new Request('http://127.0.0.1/api/system/backup/import', {
                    method: 'POST',
                    headers: { 'content-type': 'application/octet-stream' },
                    body: requestBytes,
                }),
                async () =>
                    new Response(responseBytes, {
                        status: 422,
                        headers: { 'content-type': 'application/octet-stream' },
                    }),
            );

            expect(new Uint8Array(await response.arrayBuffer())).toEqual(responseBytes);
            const trace = await waitForTerminal(entries);
            expect(
                trace.find((entry) => entry.message.includes('branch=request_body'))?.message,
            ).toContain('length=4');
            expect(
                trace.find((entry) => entry.message.includes('branch=request_body'))?.message,
            ).toContain('body=00ff8041');
            expect(
                trace.find((entry) => entry.message.includes('branch=response'))?.message,
            ).toContain('body=deadbeef00');
            expect(trace.at(-1)?.message).toMatch(
                /^webui_mutation_terminal outcome=failed reason=http_status status=422 elapsedMs=\d+$/,
            );
            expect(
                trace.filter((entry) => entry.message.startsWith('webui_mutation_terminal ')),
            ).toHaveLength(1);
        } finally {
            unsubscribe();
        }
    });

    it('traces a thrown handler with one failed terminal and preserves the error', async () => {
        const entries: LogEntry[] = [];
        setLogLevel('trace');
        const unsubscribe = subscribeLogs((entry) => entries.push(entry));
        const failure = new Error('write exploded');

        try {
            await expect(
                traceAuthenticatedWebuiMutation(
                    new Request('http://127.0.0.1/api/global-config', {
                        method: 'POST',
                        body: 'complete request',
                    }),
                    async () => {
                        throw failure;
                    },
                ),
            ).rejects.toBe(failure);

            const trace = mutationTrace(entries);
            expect(
                trace.some(
                    (entry) =>
                        entry.message.includes('branch=request_body') &&
                        entry.message.includes('body=636f6d706c6574652072657175657374'),
                ),
            ).toBe(true);
            expect(trace.at(-1)?.message).toMatch(
                /^webui_mutation_terminal outcome=failed reason=handler_threw error="write exploded" elapsedMs=\d+$/,
            );
            expect(
                trace.filter((entry) => entry.message.startsWith('webui_mutation_terminal ')),
            ).toHaveLength(1);
        } finally {
            unsubscribe();
        }
    });

    it('classifies handler cancellation and timeout from their error provenance', async () => {
        setLogLevel('trace');

        for (const [name, outcome, reason] of [
            ['AbortError', 'cancelled', 'handler_cancelled'],
            ['TimeoutError', 'timeout', 'handler_timeout'],
        ] as const) {
            const entries: LogEntry[] = [];
            const unsubscribe = subscribeLogs((entry) => entries.push(entry));
            const failure = new DOMException(`${name} detail`, name);

            try {
                await expect(
                    traceAuthenticatedWebuiMutation(
                        new Request('http://127.0.0.1/api/processes/42/load', { method: 'POST' }),
                        async () => {
                            throw failure;
                        },
                    ),
                ).rejects.toBe(failure);
                expect(mutationTrace(entries).at(-1)?.message).toMatch(
                    new RegExp(
                        `^webui_mutation_terminal outcome=${outcome} reason=${reason} error="${name} detail" elapsedMs=\\d+$`,
                    ),
                );
            } finally {
                unsubscribe();
            }
        }
    });

    it('bypasses cloning and logging when TRACE is disabled', async () => {
        const entries: LogEntry[] = [];
        setLogLevel('info');
        const unsubscribe = subscribeLogs((entry) => entries.push(entry));
        const request = new Request('http://127.0.0.1/api/system/settings', {
            method: 'POST',
            body: 'must remain unread',
        });
        const clone = vi.spyOn(request, 'clone');
        const next = vi.fn(async () => new Response('ok'));

        try {
            const response = await traceAuthenticatedWebuiMutation(request, next);
            expect(await response.text()).toBe('ok');
            expect(next).toHaveBeenCalledOnce();
            expect(clone).not.toHaveBeenCalled();
            expect(entries).toEqual([]);
        } finally {
            unsubscribe();
        }
    });

    it('does not clone the streamed upload request body', async () => {
        const entries: LogEntry[] = [];
        setLogLevel('trace');
        const unsubscribe = subscribeLogs((entry) => entries.push(entry));
        const request = new Request('http://127.0.0.1/api/debug/upload?filename=large.bin', {
            method: 'POST',
            body: Uint8Array.from([0x00, 0xff]),
        });
        const clone = vi.spyOn(request, 'clone');

        try {
            const response = await traceAuthenticatedWebuiMutation(
                request,
                async () =>
                    new Response('{"status":"ok"}', {
                        headers: { 'content-type': 'application/json' },
                    }),
            );
            expect(await response.json()).toEqual({ status: 'ok' });
            expect(clone).not.toHaveBeenCalled();
            await waitForTerminal(entries);
        } finally {
            unsubscribe();
        }
    });

    it('reports an aborted streamed upload as cancelled even when the route returns 400', async () => {
        const entries: LogEntry[] = [];
        setLogLevel('trace');
        const unsubscribe = subscribeLogs((entry) => entries.push(entry));
        const abort = new AbortController();
        const request = new Request('http://127.0.0.1/api/debug/upload?filename=cancelled.bin', {
            method: 'POST',
            body: Uint8Array.from([0x01]),
            signal: abort.signal,
        });

        try {
            abort.abort();
            const response = await traceAuthenticatedWebuiMutation(
                request,
                async () => new Response('{"status":"failed"}', { status: 400 }),
            );
            expect(response.status).toBe(400);
            const trace = await waitForTerminal(entries);
            expect(trace.at(-1)?.message).toMatch(
                /^webui_mutation_terminal outcome=cancelled reason=request_cancelled status=400 elapsedMs=\d+$/,
            );
        } finally {
            unsubscribe();
        }
    });

    it('keeps a non-abort streamed upload rejection as an HTTP failure', async () => {
        const entries: LogEntry[] = [];
        setLogLevel('trace');
        const unsubscribe = subscribeLogs((entry) => entries.push(entry));
        const request = new Request('http://127.0.0.1/api/debug/upload?filename=too-large.bin', {
            method: 'POST',
            body: Uint8Array.from([0x01]),
        });

        try {
            await traceAuthenticatedWebuiMutation(
                request,
                async () => new Response('{"status":"failed"}', { status: 400 }),
            );
            const trace = await waitForTerminal(entries);
            expect(trace.at(-1)?.message).toMatch(
                /^webui_mutation_terminal outcome=failed reason=http_status status=400 elapsedMs=\d+$/,
            );
        } finally {
            unsubscribe();
        }
    });

    it('does not pull a streaming response ahead of the client', async () => {
        const entries: LogEntry[] = [];
        setLogLevel('trace');
        const unsubscribe = subscribeLogs((entry) => entries.push(entry));
        let pulls = 0;
        const stream = new ReadableStream<Uint8Array>(
            {
                pull(controller) {
                    pulls += 1;
                    controller.enqueue(Uint8Array.from([pulls]));

                    if (pulls === 2) {
                        controller.close();
                    }
                },
            },
            { highWaterMark: 0 },
        );

        try {
            const response = await traceAuthenticatedWebuiMutation(
                new Request('http://127.0.0.1/api/debug/invoke-stream', {
                    method: 'POST',
                    body: '{}',
                }),
                async () => new Response(stream),
            );

            await Promise.resolve();
            expect(pulls).toBe(0);
            expect(new Uint8Array(await response.arrayBuffer())).toEqual(
                Uint8Array.from([0x01, 0x02]),
            );
            await waitForTerminal(entries);
        } finally {
            unsubscribe();
        }
    });

    it('returns a streaming response before its body completes and traces completion later', async () => {
        const entries: LogEntry[] = [];
        setLogLevel('trace');
        const unsubscribe = subscribeLogs((entry) => entries.push(entry));
        let controller!: ReadableStreamDefaultController<Uint8Array>;
        const stream = new ReadableStream<Uint8Array>({
            start(value) {
                controller = value;
                value.enqueue(Uint8Array.from([0x01, 0x02]));
            },
        });

        try {
            const response = await traceAuthenticatedWebuiMutation(
                new Request('http://127.0.0.1/api/debug/invoke-stream', {
                    method: 'POST',
                    body: '{}',
                }),
                async () => new Response(stream, { status: 200 }),
            );

            expect(response.body).not.toBeNull();
            expect(
                mutationTrace(entries).some((entry) =>
                    entry.message.startsWith('webui_mutation_terminal '),
                ),
            ).toBe(false);

            controller.enqueue(Uint8Array.from([0x03, 0x04]));
            controller.close();
            expect(new Uint8Array(await response.arrayBuffer())).toEqual(
                Uint8Array.from([0x01, 0x02, 0x03, 0x04]),
            );

            const trace = await waitForTerminal(entries);
            const responseChunks = trace.filter((entry) =>
                entry.message.includes('branch=response_chunk'),
            );
            expect(responseChunks.map((entry) => entry.message)).toEqual([
                'webui_mutation_branch branch=response_chunk offset=0 length=2 body=0102',
                'webui_mutation_branch branch=response_chunk offset=2 length=2 body=0304',
            ]);
            expect(trace.every((entry) => entry.req === trace[0]!.req)).toBe(true);
            expect(trace.at(-1)?.message).toMatch(
                /^webui_mutation_terminal outcome=completed reason=response_completed status=200 elapsedMs=\d+$/,
            );
        } finally {
            unsubscribe();
        }
    });

    it('records one failed terminal when the traced response body cannot be read', async () => {
        const entries: LogEntry[] = [];
        setLogLevel('trace');
        const unsubscribe = subscribeLogs((entry) => entries.push(entry));
        const streamFailure = new Error('response stream exploded');
        const stream = new ReadableStream<Uint8Array>({
            start(controller) {
                controller.enqueue(Uint8Array.from([0xaa]));
                controller.error(streamFailure);
            },
        });

        try {
            const response = await traceAuthenticatedWebuiMutation(
                new Request('http://127.0.0.1/api/debug/invoke-stream', {
                    method: 'POST',
                    body: '{}',
                }),
                async () => new Response(stream),
            );
            await expect(response.arrayBuffer()).rejects.toBe(streamFailure);

            const trace = await waitForTerminal(entries);
            expect(
                trace.some(
                    (entry) =>
                        entry.message.includes('branch=request_body') &&
                        entry.message.includes('body=7b7d'),
                ),
            ).toBe(true);
            expect(trace.at(-1)?.message).toMatch(
                /^webui_mutation_terminal outcome=failed reason=body_read_failed status=200 error="response stream exploded" elapsedMs=\d+$/,
            );
            expect(
                trace.filter((entry) => entry.message.startsWith('webui_mutation_terminal ')),
            ).toHaveLength(1);
        } finally {
            unsubscribe();
        }
    });

    it.each([
        ['GET', '/api/config/12345'],
        ['HEAD', '/api/config/12345'],
        ['OPTIONS', '/api/config/12345'],
        ['POST', '/api/auth/check-strength'],
        ['POST', '/api/logs/level'],
    ])('keeps %s %s outside mutation TRACE', async (method, pathname) => {
        const entries: LogEntry[] = [];
        setLogLevel('trace');
        const unsubscribe = subscribeLogs((entry) => entries.push(entry));
        const request = new Request(`http://127.0.0.1${pathname}`, { method });
        const clone = vi.spyOn(request, 'clone');

        try {
            await traceAuthenticatedWebuiMutation(
                request,
                async () => new Response(null, { status: 204 }),
            );
            expect(clone).not.toHaveBeenCalled();
            expect(mutationTrace(entries)).toEqual([]);
        } finally {
            unsubscribe();
        }
    });
});