import { describe, expect, it } from "@suaveplan/testing/runner";
import * as fc from "fast-check";
import { BUILTIN_DB } from "./builtin-db.js";
import type { MimeEntry } from "./mime-entry.types.js";
import {
    _indexEntryForTesting,
    getEntryByExtension,
    getMimeEntry,
    listMimeEntries,
    registerMimeEntry,
} from "./registry.js";

describe("BUILTIN_DB", () => {
    it("is a non-empty frozen array", { timeout: 5000 }, () => {
        expect(Array.isArray(BUILTIN_DB)).toBe(true);
        expect(BUILTIN_DB.length).toBeGreaterThan(50);
        expect(Object.isFrozen(BUILTIN_DB)).toBe(true);
    });

    it("contains expected common MIME types", { timeout: 5000 }, () => {
        const mimes = BUILTIN_DB.map((e) => e.mime);
        expect(mimes).toContain("image/png");
        expect(mimes).toContain("image/jpeg");
        expect(mimes).toContain("application/json");
        expect(mimes).toContain("text/html");
        expect(mimes).toContain("video/mp4");
        expect(mimes).toContain("audio/mpeg");
        expect(mimes).toContain("font/woff2");
        expect(mimes).toContain("application/pdf");
        expect(mimes).toContain("application/zip");
    });

    it("every entry has valid shape", { timeout: 5000 }, () => {
        for (const entry of BUILTIN_DB) {
            expect(typeof entry.mime).toBe("string");
            expect(entry.mime).toContain("/");
            expect(Array.isArray(entry.extensions)).toBe(true);
            expect(typeof entry.isBinary).toBe("boolean");
            expect(entry.category).toBeTruthy();
        }
    });
});

describe("getMimeEntry", () => {
    it("finds image/png by exact MIME type", { timeout: 5000 }, () => {
        const entry = getMimeEntry("image/png");
        expect(entry).toBeDefined();
        expect(entry?.mime).toBe("image/png");
        expect(entry?.category).toBe("image");
    });

    it("is case-insensitive", { timeout: 5000 }, () => {
        expect(getMimeEntry("IMAGE/PNG")).toEqual(getMimeEntry("image/png"));
    });

    it("returns undefined for unknown MIME type", { timeout: 5000 }, () => {
        expect(getMimeEntry("x/nonexistent-mime-type-12345")).toBeUndefined();
    });

    it("finds application/json with correct charset", { timeout: 5000 }, () => {
        const entry = getMimeEntry("application/json");
        expect(entry?.charset).toBe("utf-8");
        expect(entry?.compressible).toBe(true);
    });
});

describe("getEntryByExtension", () => {
    it("finds entry for 'png'", { timeout: 5000 }, () => {
        const entry = getEntryByExtension("png");
        expect(entry?.mime).toBe("image/png");
    });

    it("finds entry for '.png' (leading dot)", { timeout: 5000 }, () => {
        const entry = getEntryByExtension(".png");
        expect(entry?.mime).toBe("image/png");
    });

    it("is case-insensitive", { timeout: 5000 }, () => {
        expect(getEntryByExtension("PNG")).toEqual(getEntryByExtension("png"));
    });

    it("returns undefined for unknown extension", { timeout: 5000 }, () => {
        expect(getEntryByExtension("__not_a_real_extension__")).toBeUndefined();
    });

    it("finds 'jpg' extension", { timeout: 5000 }, () => {
        expect(getEntryByExtension("jpg")?.mime).toBe("image/jpeg");
    });

    it("finds 'json' extension", { timeout: 5000 }, () => {
        expect(getEntryByExtension("json")?.mime).toBe("application/json");
    });
});

describe("listMimeEntries", () => {
    it("returns at least as many entries as BUILTIN_DB", {
        timeout: 5000,
    }, () => {
        const list = listMimeEntries();
        expect(list.length).toBeGreaterThanOrEqual(BUILTIN_DB.length);
    });

    it("is a snapshot (different reference on each call)", {
        timeout: 5000,
    }, () => {
        const a = listMimeEntries();
        const b = listMimeEntries();
        expect(a).not.toBe(b);
    });
});

describe("registerMimeEntry", () => {
    it("adds a new entry retrievable by mime type", { timeout: 5000 }, () => {
        const custom: MimeEntry = {
            mime: "application/x-test-custom-type-99",
            extensions: ["xcustom99"],
            category: "application",
            isBinary: false,
        };
        registerMimeEntry(custom);
        const found = getMimeEntry("application/x-test-custom-type-99");
        expect(found).toEqual(custom);
    });

    it("registered entry is retrievable by extension", {
        timeout: 5000,
    }, () => {
        const custom: MimeEntry = {
            mime: "application/x-test-ext-lookup-99",
            extensions: ["xextlookup99"],
            category: "application",
            isBinary: false,
        };
        registerMimeEntry(custom);
        expect(getEntryByExtension("xextlookup99")?.mime).toBe(
            "application/x-test-ext-lookup-99"
        );
    });

    it("overrides an existing entry", { timeout: 5000 }, () => {
        const override: MimeEntry = {
            mime: "image/png",
            extensions: ["png"],
            category: "image",
            isBinary: true,
            compressible: true, // changed from false
        };
        registerMimeEntry(override);
        const found = getMimeEntry("image/png");
        expect(found?.compressible).toBe(true);
        // Reset
        registerMimeEntry({
            mime: "image/png",
            extensions: ["png"],
            category: "image",
            isBinary: true,
            compressible: false,
        });
    });

    it("appears in listMimeEntries", { timeout: 5000 }, () => {
        const custom: MimeEntry = {
            mime: "application/x-list-test-99",
            extensions: [],
            category: "application",
            isBinary: true,
        };
        registerMimeEntry(custom);
        const list = listMimeEntries();
        expect(list.some((e) => e.mime === "application/x-list-test-99")).toBe(
            true
        );
    });
});

describe("_indexEntryForTesting (duplicate extension guard)", () => {
    it("first-write-wins: duplicate extension does not override existing entry", {
        timeout: 5000,
    }, () => {
        // "png" is already mapped to image/png in the builtin DB
        const competitor: MimeEntry = {
            mime: "image/x-fake-png",
            extensions: ["png"],
            category: "image",
            isBinary: true,
        };
        _indexEntryForTesting(competitor);
        // The original image/png entry should still own the "png" extension
        const found = getEntryByExtension("png");
        expect(found?.mime).toBe("image/png");
    });
});

describe("registry round-trip (property-based)", () => {
    it("every registered entry is retrievable by mime", {
        timeout: 30000,
    }, () => {
        fc.assert(
            fc.property(
                fc.constantFrom(
                    "application",
                    "text",
                    "image",
                    "audio",
                    "video"
                ),
                fc.stringMatching(/^[a-z][a-z0-9-]+$/),
                (category, token) => {
                    const mime = `${category}/x-prop-test-${token}`;
                    const entry: MimeEntry = {
                        mime,
                        extensions: [token],
                        category: category as MimeEntry["category"],
                        isBinary: false,
                    };
                    registerMimeEntry(entry);
                    const found = getMimeEntry(mime);
                    expect(found?.mime).toBe(mime);
                }
            )
        );
    });
});