/**
 * DTP-25 — `FileLocation.storageHints` `kind: 'inline'` carries a sig
 * over `fileId ‖ bytes`. Verified by the three required spec test
 * names plus tamper-detection cases.
 */

import {
    getPublicKey,
    randomPrivateKey,
} from "@suaveplan/crypto-curve/ed25519";
import { describe, expect, it } from "@suaveplan/testing/runner";
import {
    CHUNKS_CODES,
    ChunksError,
    inlineSigningInput,
    isLegacyInlineHint,
    type LegacyInlineHint,
    signInlineHint,
    upgradeLegacyInlineHint,
    verifyInlineHint,
} from "../src/index.js";

function makeFileId(seed: number): Uint8Array {
    const id = new Uint8Array(32);
    for (let i = 0; i < 32; i++) id[i] = (seed + i) & 0xff;
    return id;
}

describe("DTP-25 — inline-file sig", () => {
    it("inline file with valid sig reads successfully", {
        timeout: 5000,
    }, () => {
        const sk = randomPrivateKey();
        const pk = getPublicKey(sk);
        const fileId = makeFileId(0x10);
        const bytes = new TextEncoder().encode("hello inline world");
        const hint = signInlineHint(fileId, bytes, sk);

        const out = verifyInlineHint(hint, fileId, pk);

        expect(out).toEqual(bytes);
        expect(hint.kind).toBe("inline");
        expect(hint.sig).toBeInstanceOf(Uint8Array);
        expect(hint.sig.byteLength).toBe(64);
    });

    it("inline file with bad sig throws INLINE_SIG_INVALID", {
        timeout: 5000,
    }, () => {
        const sk = randomPrivateKey();
        const pk = getPublicKey(sk);
        const fileId = makeFileId(0x20);
        const bytes = new TextEncoder().encode("payload");
        const hint = signInlineHint(fileId, bytes, sk);
        // Flip a bit in the signature.
        const tamperedSig = new Uint8Array(hint.sig);
        tamperedSig[0] ^= 0x01;
        const tampered = { ...hint, sig: tamperedSig };

        try {
            verifyInlineHint(tampered, fileId, pk);
            throw new Error("expected INLINE_SIG_INVALID");
        } catch (err) {
            expect(err).toBeInstanceOf(ChunksError);
            expect((err as ChunksError).code).toBe(
                CHUNKS_CODES.INLINE_SIG_INVALID
            );
        }
    });

    it("old-format inline reads with warning AND rewrites with sig on next write", {
        timeout: 5000,
    }, () => {
        const sk = randomPrivateKey();
        const pk = getPublicKey(sk);
        const fileId = makeFileId(0x30);
        const bytes = new TextEncoder().encode("legacy bytes");
        const legacy: LegacyInlineHint = { kind: "inline", bytes };

        // Legacy detection
        expect(isLegacyInlineHint(legacy)).toBe(true);

        // Simulate the warning channel a real drive would emit on read
        let warningCount = 0;
        const onWarning = () => {
            warningCount++;
        };
        if (isLegacyInlineHint(legacy)) {
            onWarning();
        }
        expect(warningCount).toBe(1);

        // Rewrite-with-sig on next write
        const upgraded = upgradeLegacyInlineHint(legacy, fileId, sk);
        expect(isLegacyInlineHint(upgraded)).toBe(false);
        expect(upgraded.bytes).toEqual(bytes);
        expect(upgraded.sig.byteLength).toBe(64);

        // Upgraded hint verifies cleanly under the same key
        const verified = verifyInlineHint(upgraded, fileId, pk);
        expect(verified).toEqual(bytes);
    });

    it("sig bound to fileId — replay onto a different fileId rejects", {
        timeout: 5000,
    }, () => {
        const sk = randomPrivateKey();
        const pk = getPublicKey(sk);
        const fileIdA = makeFileId(0x40);
        const fileIdB = makeFileId(0x41);
        const bytes = new TextEncoder().encode("same bytes, different file");
        const hint = signInlineHint(fileIdA, bytes, sk);

        try {
            verifyInlineHint(hint, fileIdB, pk);
            throw new Error("expected INLINE_SIG_INVALID");
        } catch (err) {
            expect((err as ChunksError).code).toBe(
                CHUNKS_CODES.INLINE_SIG_INVALID
            );
        }
    });

    it("byte tamper rejects with INLINE_SIG_INVALID", { timeout: 5000 }, () => {
        const sk = randomPrivateKey();
        const pk = getPublicKey(sk);
        const fileId = makeFileId(0x50);
        const bytes = new TextEncoder().encode("original");
        const hint = signInlineHint(fileId, bytes, sk);
        const tamperedBytes = new TextEncoder().encode("modified");
        const tampered = { ...hint, bytes: tamperedBytes };

        try {
            verifyInlineHint(tampered, fileId, pk);
            throw new Error("expected INLINE_SIG_INVALID");
        } catch (err) {
            expect((err as ChunksError).code).toBe(
                CHUNKS_CODES.INLINE_SIG_INVALID
            );
        }
    });

    it("rejects under a different public key", { timeout: 5000 }, () => {
        const skA = randomPrivateKey();
        const skB = randomPrivateKey();
        const pkB = getPublicKey(skB);
        const fileId = makeFileId(0x60);
        const bytes = new TextEncoder().encode("signed by A");
        const hint = signInlineHint(fileId, bytes, skA);

        expect(() => verifyInlineHint(hint, fileId, pkB)).toThrow(ChunksError);
    });

    it("inlineSigningInput is the canonical fileId ‖ bytes concatenation", {
        timeout: 5000,
    }, () => {
        const fileId = new Uint8Array([1, 2, 3, 4]);
        const bytes = new Uint8Array([0xaa, 0xbb, 0xcc]);
        const input = inlineSigningInput(fileId, bytes);
        expect(input.byteLength).toBe(7);
        expect(Array.from(input)).toEqual([1, 2, 3, 4, 0xaa, 0xbb, 0xcc]);
    });

    it("verify catch arm wraps a throwing verifier", { timeout: 5000 }, () => {
        const sk = randomPrivateKey();
        const pk = getPublicKey(sk);
        const fileId = makeFileId(0x70);
        const bytes = new TextEncoder().encode("ok");
        const hint = signInlineHint(fileId, bytes, sk);

        const throwingVerify = () => {
            throw new Error("native verifier exploded");
        };

        try {
            verifyInlineHint(hint, fileId, pk, throwingVerify);
            throw new Error("expected INLINE_SIG_INVALID");
        } catch (err) {
            expect(err).toBeInstanceOf(ChunksError);
            const e = err as ChunksError;
            expect(e.code).toBe(CHUNKS_CODES.INLINE_SIG_INVALID);
            expect(e.message).toContain("raised");
            expect(e.cause).toBeInstanceOf(Error);
            expect((e.cause as Error).message).toBe("native verifier exploded");
        }
    });

    it("isLegacyInlineHint distinguishes signed from legacy hints", {
        timeout: 5000,
    }, () => {
        const sk = randomPrivateKey();
        const fileId = makeFileId(0x80);
        const bytes = new TextEncoder().encode("data");
        const signed = signInlineHint(fileId, bytes, sk);
        const legacy: LegacyInlineHint = { kind: "inline", bytes };

        expect(isLegacyInlineHint(signed)).toBe(false);
        expect(isLegacyInlineHint(legacy)).toBe(true);

        // Object literally has sig: undefined — also treated as legacy.
        const ambiguous = { kind: "inline" as const, bytes, sig: undefined };
        expect(
            isLegacyInlineHint(ambiguous as unknown as LegacyInlineHint)
        ).toBe(true);
    });
});