import { secp256k1 } from "@suaveplan/crypto-curve";
import { describe, expect, it } from "@suaveplan/testing/runner";
import fc from "fast-check";
import { packPayload, unpackPayload } from "../src/codec/payload/payload.js";
import { LICENSE_SCHEMA } from "../src/constants/constants.js";
import { generateLicense } from "../src/generate/generate.js";
import {
    type LicensePayload,
    LicenseValidationError,
    TimeEncodingType,
} from "../src/types/license.js";
import { validateLicense } from "../src/validate/validate.js";

const payloadArb = fc.record({
    version: fc.integer({ min: 0, max: LICENSE_SCHEMA.version }),
    signingKeyId: fc.integer({ min: 0, max: LICENSE_SCHEMA.signingKeyId }),
    productId: fc.integer({ min: 0, max: LICENSE_SCHEMA.productId }),
    packageTier: fc.integer({ min: 0, max: LICENSE_SCHEMA.packageTier }),
    flags: fc.integer({ min: 0, max: LICENSE_SCHEMA.flags }),
    timeEncodingType: fc
        .integer({ min: 0, max: LICENSE_SCHEMA.timeEncodingType })
        .map((v) => v as TimeEncodingType),
    timeValue: fc.integer({ min: 0, max: LICENSE_SCHEMA.timeValue }),
    featureMask: fc.integer({ min: 0, max: LICENSE_SCHEMA.featureMask }),
    nonce: fc.integer({ min: 0, max: LICENSE_SCHEMA.nonce }),
});

function fresh() {
    const s = secp256k1.randomPrivateKey();
    const p = secp256k1.getPublicKey(s);
    return { signingKey: { s, p }, publicKey: { p } };
}

describe("property tests", () => {
    it("unpackPayload inverts packPayload", { timeout: 30000 }, () => {
        fc.assert(
            fc.property(payloadArb, (payload: LicensePayload) => {
                const bytes = packPayload(payload);
                expect(bytes.length).toBe(9);
                const decoded = unpackPayload(bytes);
                expect(decoded).toEqual(payload);
            }),
            { numRuns: 200 }
        );
    });

    it("1-byte mutation surfaces as INVALID_SIGNATURE or MALFORMED", {
        timeout: 60000,
    }, async () => {
        const { signingKey, publicKey } = fresh();
        // Sample once at the boundary; we mutate the generated key's
        // characters for the actual property under test.
        const payload: LicensePayload = {
            version: 2,
            signingKeyId: 0,
            productId: 1,
            packageTier: 0,
            flags: 0,
            timeEncodingType: TimeEncodingType.NONE,
            timeValue: 0,
            featureMask: 0,
            nonce: 0x111,
        };
        const r = await generateLicense(payload, {
            signingKey,
            useFullSignature: false,
        });
        const validPubKeys = new Map([[0, publicKey]]);

        const keyLen = r.key.length;
        // The Base32 encoding of 29 bytes uses 47 chars; chars after
        // that are padding bits that may not affect decoded bytes.
        // We bound the tamper-index so it always lands on a
        // semantically-significant character.
        await fc.assert(
            fc.asyncProperty(
                fc.integer({ min: 0, max: keyLen - 2 }),
                fc.integer({ min: 0, max: 31 }),
                async (idx, alphabetIdx) => {
                    const chars = r.key.split("");
                    if (chars[idx] === "-") return true; // skip dashes
                    const ALPHABET = "0123456789ABCDEFGHJKMNPQRSTVWXYZ";
                    const newChar = ALPHABET[alphabetIdx] as string;
                    if (chars[idx] === newChar) return true; // no-op mutation
                    chars[idx] = newChar;
                    const tampered = chars.join("");
                    const v = await validateLicense(tampered, {
                        publicKeys: validPubKeys,
                    });
                    // Base32 has trailing padding bits; a character
                    // change in the final bit-positions may decode to
                    // the same bytes, producing a valid key. That is
                    // acceptable — we only need to assert that NO tamper
                    // produces a *different* valid license that the
                    // validator wrongly trusts as the original payload.
                    if (v.success) {
                        return (
                            v.details.nonce === payload.nonce &&
                            v.details.productId === payload.productId
                        );
                    }
                    return [
                        LicenseValidationError.INVALID_SIGNATURE,
                        LicenseValidationError.MALFORMED,
                        LicenseValidationError.INVALID_ENCODING,
                        LicenseValidationError.UNKNOWN_SIGNING_KEY,
                        LicenseValidationError.UNSUPPORTED_VERSION,
                        LicenseValidationError.EXPIRED,
                    ].includes(v.error);
                }
            ),
            { numRuns: 200 }
        );
    });

    it("expired trial always fails validation", {
        timeout: 60000,
    }, async () => {
        const { signingKey, publicKey } = fresh();
        await fc.assert(
            fc.asyncProperty(
                fc.integer({ min: 1, max: 365 }),
                async (durationDays) => {
                    const payload: LicensePayload = {
                        version: 2,
                        signingKeyId: 0,
                        productId: 1,
                        packageTier: 0,
                        flags: 1, // TRIAL
                        timeEncodingType: TimeEncodingType.RELATIVE_DAYS,
                        timeValue: durationDays,
                        featureMask: 0,
                        nonce: 7,
                    };
                    const r = await generateLicense(payload, {
                        signingKey,
                        useFullSignature: false,
                    });
                    const creation = new Date("2026-01-01T00:00:00Z");
                    const past =
                        creation.getTime() + (durationDays + 1) * 86_400_000;
                    const v = await validateLicense(r.key, {
                        publicKeys: new Map([[0, publicKey]]),
                        creationDate: creation,
                        referenceDate: new Date(past),
                    });
                    return (
                        !v.success && v.error === LicenseValidationError.EXPIRED
                    );
                }
            ),
            { numRuns: 50 }
        );
    });
});