import { promiseWithResolvers } from "octagonal-wheels/promises";
import { reactiveSource } from "octagonal-wheels/dataobject/reactive";
import { describe, expect, it, vi } from "vitest";
import {
    VERSIONING_DOCID,
    type EntryDoc,
    type FilePathWithPrefix,
} from "@vrtmrz/livesync-commonlib/compat/common/types";
import { ENCRYPTED_INTERNAL_METADATA_FEATURE, REMOTE_FEATURE_GENERATION } from "@vrtmrz/livesync-commonlib/replication";
import {
    isValidFilenameInAndroid,
    isValidFilenameInWidows,
} from "@vrtmrz/livesync-commonlib/compat/string_and_binary/path";
import {
    defaultLogger,
    LOG_LEVEL_DEBUG,
    LOG_LEVEL_NOTICE,
    LOG_LEVEL_VERBOSE,
    setGlobalLogFunction,
} from "octagonal-wheels/common/logger";
import { ReplicateResultProcessor } from "./ReplicateResultProcessor";

function note(id: string): PouchDB.Core.ExistingDocument<EntryDoc> {
    return {
        _id: id,
        _rev: "1-test",
        path: `${id}.md`,
        ctime: 1,
        mtime: 2,
        size: 1,
        children: [],
        datatype: "plain",
        type: "plain",
        eden: {},
    } as unknown as PouchDB.Core.ExistingDocument<EntryDoc>;
}

type SetupOptions = {
    applicationReady?: boolean;
    databaseReady?: boolean;
    maxMTimeForReflectEvents?: number;
    isValidPath?: (path: string) => boolean;
    processSynchroniseResult?: (entry: unknown) => Promise<boolean>;
    setSnapshot?: (key: string, value: unknown) => Promise<unknown>;
    getSnapshot?: (key: string) => Promise<unknown>;
    localVersionInfo?: unknown;
    isTargetFile?: (path: string) => Promise<boolean>;
    databaseId?: string;
};

function setup(options: SetupOptions = {}) {
    const processSynchroniseResult = vi.fn(options.processSynchroniseResult ?? (async () => true));
    const setSnapshot = vi.fn(options.setSnapshot ?? (async () => undefined));
    const runBoundedLocalApplicationActivity = vi.fn(async (task: () => Promise<void>) => await task());
    const onCloseActiveReplication = vi.fn(async () => true);
    const isReady = vi.fn(() => options.applicationReady ?? true);
    const isValidPath = vi.fn(options.isValidPath ?? (() => true));
    const getDBEntryFromMeta = vi.fn(async (entry: object) => ({ ...entry, data: "x" }));
    const localPhysicalDatabase = {
        ...(options.databaseId ? { id: vi.fn(async () => options.databaseId) } : {}),
    } as PouchDB.Database<EntryDoc>;
    const core = {
        services: {
            appLifecycle: { isReady, isSuspended: () => false },
            database: { isDatabaseReady: () => options.databaseReady ?? true },
            path: { getPath: (entry: { path: string }) => entry.path },
            replication: {
                databaseQueueCount: reactiveSource(0),
                storageApplyingCount: reactiveSource(0),
                replicationResultCount: reactiveSource(0),
                processVirtualDocument: vi.fn(async () => false),
                processOptionalSynchroniseResult: vi.fn(async () => false),
                processSynchroniseResult,
            },
            replicator: { onCloseActiveReplication, runBoundedLocalApplicationActivity },
            vault: {
                isTargetFile: vi.fn(options.isTargetFile ?? (async () => true)),
                isFileSizeTooLarge: vi.fn(() => false),
                isValidPath,
            },
        },
        kvDB: { set: setSnapshot, get: vi.fn(options.getSnapshot ?? (async () => undefined)) },
        localDatabase: {
            localDatabase: localPhysicalDatabase,
            getRaw: vi.fn(async (id: string) => {
                if (id === VERSIONING_DOCID) {
                    if (options.localVersionInfo === undefined) throw { status: 404 };
                    return options.localVersionInfo;
                }
                return { _id: id, _rev: "1-test" };
            }),
            getDBEntryFromMeta,
        },
    };
    const processor = new ReplicateResultProcessor({
        currentSettings: () => ({
            maxMTimeForReflectEvents: options.maxMTimeForReflectEvents ?? 0,
            suspendParseReplicationResult: false,
        }),
        getKeyValueDB: () => core.kvDB,
        getLocalDatabase: () => core.localDatabase,
        requestActiveReplicatorRetirement: () => {
            void onCloseActiveReplication();
        },
        runLocalApplicationActivity: runBoundedLocalApplicationActivity,
        services: core.services,
    } as never);
    return {
        getDBEntryFromMeta,
        isTargetFile: core.services.vault.isTargetFile,
        localPhysicalDatabase,
        localDatabase: core.localDatabase,
        isReady,
        isValidPath,
        onCloseActiveReplication,
        processor,
        processSynchroniseResult,
        runBoundedLocalApplicationActivity,
    };
}

describe("ReplicateResultProcessor", () => {
    it("does not add a permanent application block when snapshot recovery fails", async () => {
        const { processor } = setup({
            getSnapshot: async () => {
                throw new Error("KV unavailable");
            },
        });
        await expect(processor.restoreFromSnapshotOnce()).rejects.toThrow("KV unavailable");
        expect(processor.isSuspended).toBe(false);
    });

    it("restores pending notes without retaining a past feature rejection in KV", async () => {
        const { processor, processSynchroniseResult, onCloseActiveReplication } = setup({
            databaseId: "same-database",
            getSnapshot: async () => ({
                databaseId: "same-database",
                invalidControlObserved: true,
                observedFeatures: ["future-format-v7"],
                observedGeneration: 14,
                queued: [note("recovered-note")],
                processing: [],
            }),
        });
        await processor.restoreFromSnapshotOnce();
        expect(processor.isSuspended).toBe(false);
        await vi.waitFor(() => expect(processSynchroniseResult).toHaveBeenCalledOnce());
        expect(onCloseActiveReplication).not.toHaveBeenCalled();
    });

    it.each([
        ["Windows", isValidFilenameInWidows],
        ["Android", isValidFilenameInAndroid],
    ])("does not reflect a replicated colon path into the %s Vault", async (_platform, validatePath) => {
        const path = "Folder/Poem: Example.md" as FilePathWithPrefix;
        const document = { ...note("colon-path"), path };
        const { getDBEntryFromMeta, isValidPath, processor, processSynchroniseResult } = setup({
            isValidPath: validatePath,
        });

        processor.enqueueAll([document]);

        await vi.waitFor(() => expect(isValidPath).toHaveBeenCalledWith(path));
        await vi.waitFor(() => expect(processor["_processingChanges"]).toHaveLength(0));
        expect(getDBEntryFromMeta).toHaveBeenCalledWith(expect.objectContaining({ path }), false, true);
        expect(processSynchroniseResult).not.toHaveBeenCalled();
    });

    it("resumes another document after in-flight updates to one document fill the application slots", async () => {
        const hotGate = promiseWithResolvers<boolean>();
        const { processor, processSynchroniseResult } = setup({
            processSynchroniseResult: async (entry) => {
                if ((entry as { _id: string })._id === "hot-queue") return await hotGate.promise;
                return true;
            },
        });
        try {
            for (let index = 1; index <= 10; index++) {
                // A queued duplicate is coalesced; a new notification for a document
                // already being processed can occupy another application slot.
                processor.enqueueAll([note("hot-queue")]);
                await vi.waitFor(() => expect(processor["_processingChanges"]).toHaveLength(index));
            }
            processor.enqueueAll([note("unrelated-queue")]);
            await vi.waitFor(() => {
                expect(processor["_semaphore"].waiting).toBeGreaterThan(0);
                expect(processSynchroniseResult).toHaveBeenCalledTimes(1);
            });
            expect(processor["_queuedChanges"].map((entry) => entry._id)).toEqual(["unrelated-queue"]);
        } finally {
            hotGate.resolve(true);
            await vi.waitFor(() => {
                expect(processor["_processingChanges"]).toHaveLength(0);
                expect(processor["_queuedChanges"]).toHaveLength(0);
            });
        }
        expect(processSynchroniseResult).toHaveBeenCalledTimes(11);
        expect(
            processSynchroniseResult.mock.calls.some(([entry]) => (entry as { _id: string })._id === "unrelated-queue")
        ).toBe(true);
    });

    it("suspends result application while the application is not ready", () => {
        const { isReady, processor } = setup({ applicationReady: false });

        expect(processor.isSuspended).toBe(true);
        expect(isReady).toHaveBeenCalledOnce();
    });

    it("applies documents held before readiness once the application becomes ready", async () => {
        const { isReady, processor, processSynchroniseResult } = setup({ applicationReady: false });
        processor.enqueueAll([note("held")]);
        await new Promise((resolve) => setTimeout(resolve, 0));
        expect(processSynchroniseResult).not.toHaveBeenCalled();
        expect(processor["_queuedChanges"]).toHaveLength(1);

        isReady.mockReturnValue(true);
        processor.continueHeldDocuments();

        await vi.waitFor(() => expect(processSynchroniseResult).toHaveBeenCalledOnce());
        expect(processor["_queuedChanges"]).toHaveLength(0);
    });

    it("keeps an explicit suspension when the application becomes ready", async () => {
        const { isReady, processor, processSynchroniseResult } = setup({ applicationReady: false });
        processor.suspend();
        processor.enqueueAll([note("held")]);

        isReady.mockReturnValue(true);
        processor.continueHeldDocuments();
        await new Promise((resolve) => setTimeout(resolve, 0));
        expect(processSynchroniseResult).not.toHaveBeenCalled();
        expect(processor["_queuedChanges"]).toHaveLength(1);

        processor.resume();
        await vi.waitFor(() => expect(processSynchroniseResult).toHaveBeenCalledOnce());
    });

    it("applies results in remediation mode, which never reports readiness", () => {
        const { processor } = setup({
            applicationReady: false,
            maxMTimeForReflectEvents: Date.parse("2026-09-01T00:00:00Z"),
        });

        expect(processor.isSuspended).toBe(false);
    });

    it("holds results in remediation mode while the local database is being rebuilt", () => {
        const { processor } = setup({
            applicationReady: false,
            databaseReady: false,
            maxMTimeForReflectEvents: Date.parse("2026-09-01T00:00:00Z"),
        });

        expect(processor.isSuspended).toBe(true);
    });

    it("still skips a document modified after the limit while the application is unready", async () => {
        const maxMTimeForReflectEvents = Date.parse("2026-09-01T00:00:00Z");
        const { processor, processSynchroniseResult } = setup({
            applicationReady: false,
            maxMTimeForReflectEvents,
        });

        const tooRecent = {
            ...note("too-recent"),
            mtime: maxMTimeForReflectEvents + 1,
        } as PouchDB.Core.ExistingDocument<EntryDoc>;
        processor.enqueueAll([tooRecent]);

        await vi.waitFor(() => {
            expect(processor["_queuedChanges"]).toHaveLength(0);
            expect(processor["_processingChanges"]).toHaveLength(0);
        });
        expect(processSynchroniseResult).not.toHaveBeenCalled();
    });

    it("retires active ownership when a newer remote version is observed", async () => {
        const { onCloseActiveReplication, processor } = setup();
        const versionInfo = {
            _id: VERSIONING_DOCID,
            _rev: "1-test",
            type: "versioninfo",
            version: REMOTE_FEATURE_GENERATION + 1,
        } as unknown as PouchDB.Core.ExistingDocument<EntryDoc>;

        processor.enqueueAll([versionInfo]);

        await vi.waitFor(() => expect(onCloseActiveReplication).toHaveBeenCalledOnce());
    });

    it("continues applying documents after restoring a legacy local version document", async () => {
        const { onCloseActiveReplication, processor, processSynchroniseResult } = setup({
            localVersionInfo: {
                _id: VERSIONING_DOCID,
                type: "versioninfo",
                version: 11,
            },
        });

        await processor.restoreFromSnapshotOnce();
        processor.enqueueAll([note("legacy-database-note")]);

        await vi.waitFor(() => expect(processSynchroniseResult).toHaveBeenCalledOnce());
        expect(processor.isSuspended).toBe(false);
        expect(onCloseActiveReplication).not.toHaveBeenCalled();
    });

    it("continues when a newly received feature is supported", async () => {
        const { onCloseActiveReplication, processor, processSynchroniseResult } = setup();
        const versionInfo = {
            _id: VERSIONING_DOCID,
            _rev: "2-supported",
            type: "versioninfo",
            version: REMOTE_FEATURE_GENERATION,
            used_features: [ENCRYPTED_INTERNAL_METADATA_FEATURE],
        } as PouchDB.Core.ExistingDocument<EntryDoc>;

        processor.enqueueAll([versionInfo, note("supported-update")]);

        await vi.waitFor(() => expect(processSynchroniseResult).toHaveBeenCalledOnce());
        expect(onCloseActiveReplication).not.toHaveBeenCalled();
    });

    it("reports unknown feature identifiers and requests Replicator retirement", () => {
        const logger = vi.fn();
        setGlobalLogFunction(logger);
        try {
            const { processor, onCloseActiveReplication } = setup();
            processor.enqueueAll([
                {
                    _id: VERSIONING_DOCID,
                    _rev: "1-unknown",
                    type: "versioninfo",
                    version: REMOTE_FEATURE_GENERATION,
                    used_features: ["future-format-v7"],
                } as PouchDB.Core.ExistingDocument<EntryDoc>,
            ]);
            expect(onCloseActiveReplication).toHaveBeenCalledOnce();
            expect(logger).toHaveBeenCalledWith(
                expect.stringContaining("future-format-v7"),
                LOG_LEVEL_NOTICE,
                undefined
            );
        } finally {
            setGlobalLogFunction(defaultLogger);
        }
    });

    it("scans normal-file metadata without loading chunk documents and requeues it", async () => {
        const documents = [
            { _id: "first", _rev: "1-a", type: "plain", path: "first.md" },
            { _id: "second", _rev: "1-b", type: "plain", path: "second.md" },
        ] as unknown as PouchDB.Core.ExistingDocument<EntryDoc>[];
        const findAllNormalDocs = vi.fn(async function* () {
            yield* documents;
        });
        const getLocalDatabase = vi.fn(() => ({ findAllNormalDocs }));
        const processor = new ReplicateResultProcessor({
            getLocalDatabase,
        } as never);
        const enqueueAll = vi.spyOn(processor, "enqueueAll").mockImplementation(() => undefined);

        await expect(processor.reprocessStoredDocuments()).resolves.toBe(2);

        expect(findAllNormalDocs).toHaveBeenCalledOnce();
        expect(getLocalDatabase).toHaveBeenCalledOnce();
        expect(enqueueAll).toHaveBeenCalledOnce();
        expect(enqueueAll).toHaveBeenCalledWith(documents);
    });

    it("keeps one local application activity until every replicated document has been applied", async () => {
        const applying = promiseWithResolvers<boolean>();
        let activityFinished = false;
        const { processor, processSynchroniseResult, runBoundedLocalApplicationActivity } = setup({
            processSynchroniseResult: async () => applying.promise,
        });
        runBoundedLocalApplicationActivity.mockImplementation(async (task: () => Promise<void>) => {
            await task();
            activityFinished = true;
        });

        processor.enqueueAll([note("one"), note("two")]);

        await vi.waitFor(() => expect(processSynchroniseResult).toHaveBeenCalledTimes(2));
        expect(runBoundedLocalApplicationActivity).toHaveBeenCalledTimes(1);
        expect(runBoundedLocalApplicationActivity).toHaveBeenCalledWith(expect.any(Function), {
            label: "replicated-document-application",
        });
        expect(activityFinished).toBe(false);

        applying.resolve(true);

        await vi.waitFor(() => expect(activityFinished).toBe(true));
    });

    it("settles local application activity when the final recovery snapshot fails", async () => {
        let activityFinished = false;
        const { processor, runBoundedLocalApplicationActivity } = setup({
            setSnapshot: async () => Promise.reject(new Error("snapshot failed")),
        });
        runBoundedLocalApplicationActivity.mockImplementation(async (task: () => Promise<void>) => {
            await task();
            activityFinished = true;
        });

        processor.enqueueAll([note("one")]);

        await vi.waitFor(() => expect(activityFinished).toBe(true));
    });

    it("releases and reacquires local application activity around processing suspension", async () => {
        const applying = promiseWithResolvers<boolean>();
        let completedActivities = 0;
        const { processor, processSynchroniseResult, runBoundedLocalApplicationActivity } = setup({
            processSynchroniseResult: async () => applying.promise,
        });
        runBoundedLocalApplicationActivity.mockImplementation(async (task: () => Promise<void>) => {
            await task();
            completedActivities++;
        });
        processor.enqueueAll([note("one")]);
        await vi.waitFor(() => expect(processSynchroniseResult).toHaveBeenCalledOnce());

        processor.suspend();
        await vi.waitFor(() => expect(completedActivities).toBe(1));

        processor.resume();
        await vi.waitFor(() => expect(runBoundedLocalApplicationActivity).toHaveBeenCalledTimes(2));

        applying.resolve(true);
        await vi.waitFor(() => expect(completedActivities).toBe(2));
    });

    it.each([
        ["returns false", async () => false, undefined],
        ["throws", async () => Promise.reject(new Error("File name too long")), "File name too long"],
    ])("reports when Vault reflection %s", async (_description, processSynchroniseResult, errorMessage) => {
        const log = vi.fn((_message: unknown, _level?: number) => undefined);
        setGlobalLogFunction(log);
        try {
            const { processor } = setup({ processSynchroniseResult });

            processor.enqueueAll([note("unreflectable")]);

            await vi.waitFor(() =>
                expect(log).toHaveBeenCalledWith(
                    "Not all files could be synchronised. Check the affected files. Generate a report to review the detailed log.",
                    LOG_LEVEL_NOTICE,
                    undefined
                )
            );
            expect(log).toHaveBeenCalledWith(
                "[ReplicateResultProcessor] Live replication could not reflect unreflectable.md from the local database to the Vault; this path remains eligible for a later Vault scan.",
                LOG_LEVEL_VERBOSE,
                undefined
            );
            if (errorMessage !== undefined) {
                expect(log).toHaveBeenCalledWith(
                    expect.objectContaining({ message: errorMessage }),
                    LOG_LEVEL_VERBOSE,
                    undefined
                );
            }
            expect(log).not.toHaveBeenCalledWith(
                expect.stringContaining("Processed: unreflectable.md"),
                LOG_LEVEL_DEBUG,
                undefined
            );
        } finally {
            setGlobalLogFunction(defaultLogger);
        }
    });
});