import { readFileSync } from "node:fs";
import { join } from "node:path";
import { SuaveplanError } from "@suaveplan/error";
import { describe, expect, expectTypeOf, it } from "@suaveplan/testing/runner";
import {
    TPM_STRUCT_CODES,
    TpmStructError,
    type TpmStructErrorCode,
    tpmStructError,
} from "./error-codes.js";

const SRC_ROOT = join(import.meta.dirname, "..");

describe("TPM_STRUCT_CODES", () => {
    it("contains exactly the 10 documented codes", { timeout: 5000 }, () => {
        const keys = Object.keys(TPM_STRUCT_CODES).sort();
        expect(keys).toEqual([
            "ALG_UNSUPPORTED",
            "ATTEST_TYPE_UNSUPPORTED",
            "CURVE_UNSUPPORTED",
            "MAGIC_INVALID",
            "MALFORMED",
            "NAME_ALG_NULL",
            "OBJECT_ATTRIBUTES_RESERVED_NONZERO",
            "PARAMETERS_INVALID",
            "TRUNCATED",
            "TYPE_MISMATCH",
        ]);
        for (const k of keys) {
            expect(TPM_STRUCT_CODES[k as keyof typeof TPM_STRUCT_CODES]).toBe(
                `TPM_STRUCT.${k}`
            );
        }
    });

    it("every TPM_STRUCT code reachable from a production path", {
        timeout: 5000,
    }, () => {
        const sources = readSrcSources(SRC_ROOT);
        for (const code of Object.values(TPM_STRUCT_CODES)) {
            const reason = (code as string).split(".")[1] as string;
            const found = sources.some(({ body }) => body.includes(reason));
            expect(found, `code ${code} not referenced in src/`).toBe(true);
        }
    });

    it("literal union pins to registry keys", { timeout: 5000 }, () => {
        expectTypeOf<TpmStructErrorCode>().toEqualTypeOf<
            | "TPM_STRUCT.MAGIC_INVALID"
            | "TPM_STRUCT.TRUNCATED"
            | "TPM_STRUCT.ALG_UNSUPPORTED"
            | "TPM_STRUCT.CURVE_UNSUPPORTED"
            | "TPM_STRUCT.TYPE_MISMATCH"
            | "TPM_STRUCT.MALFORMED"
            | "TPM_STRUCT.NAME_ALG_NULL"
            | "TPM_STRUCT.ATTEST_TYPE_UNSUPPORTED"
            | "TPM_STRUCT.PARAMETERS_INVALID"
            | "TPM_STRUCT.OBJECT_ATTRIBUTES_RESERVED_NONZERO"
        >();
    });
});

describe("TpmStructError", () => {
    it("instances carry the TPM_STRUCT.* code literal", {
        timeout: 5000,
    }, () => {
        const err = tpmStructError(TPM_STRUCT_CODES.MAGIC_INVALID, "test");
        expect(err).toBeInstanceOf(TpmStructError);
        expect(err).toBeInstanceOf(SuaveplanError);
        expect(err.code).toBe("TPM_STRUCT.MAGIC_INVALID");
        expect(err.message).toContain("TPM_STRUCT.MAGIC_INVALID");
    });

    it("threads structured detail through the cause chain", {
        timeout: 5000,
    }, () => {
        const err = tpmStructError(TPM_STRUCT_CODES.TRUNCATED, "short", {
            cursor: 5,
            requested: 4,
        });
        const cause = (
            err as unknown as {
                cause: Error & { detail?: Record<string, unknown> };
            }
        ).cause;
        expect(cause).toBeInstanceOf(Error);
        expect(cause?.detail).toEqual({ cursor: 5, requested: 4 });
    });

    it("constructor without options has no cause", { timeout: 5000 }, () => {
        const err = new TpmStructError(TPM_STRUCT_CODES.MALFORMED, "no opts");
        expect(err.code).toBe("TPM_STRUCT.MALFORMED");
        expect((err as unknown as { cause?: unknown }).cause).toBeUndefined();
    });

    it("constructor accepts an Error cause directly", {
        timeout: 5000,
    }, () => {
        const inner = new Error("inner");
        const err = new TpmStructError(TPM_STRUCT_CODES.MALFORMED, "outer", {
            cause: inner,
        });
        expect((err as unknown as { cause: Error }).cause).toBe(inner);
    });

    it("constructor silently drops non-Error causes", {
        timeout: 5000,
    }, () => {
        const err = new TpmStructError(TPM_STRUCT_CODES.MALFORMED, "outer", {
            cause: "string-not-error",
        });
        expect((err as unknown as { cause?: unknown }).cause).toBeUndefined();
    });

    it("tpmStructError without detail has no cause", {
        timeout: 5000,
    }, () => {
        const err = tpmStructError(TPM_STRUCT_CODES.MALFORMED, "bare");
        expect((err as unknown as { cause?: unknown }).cause).toBeUndefined();
    });
});

type SrcSource = { path: string; body: string };

function readSrcSources(root: string): SrcSource[] {
    const out: SrcSource[] = [];
    // biome lint hint: this is a test helper; readdirSync is the simplest walker
    const fs = require("node:fs") as typeof import("node:fs");
    function walk(dir: string): void {
        for (const entry of fs.readdirSync(dir, { withFileTypes: true })) {
            const full = join(dir, entry.name);
            if (entry.isDirectory()) {
                if (
                    entry.name === "__fixtures__" ||
                    entry.name === "__benchmarks__" ||
                    entry.name === "__integration__"
                ) {
                    continue;
                }
                walk(full);
            } else if (
                entry.name.endsWith(".ts") &&
                !entry.name.endsWith(".test.ts") &&
                !entry.name.endsWith(".types.ts") &&
                !entry.name.endsWith(".bench.ts")
            ) {
                out.push({ path: full, body: readFileSync(full, "utf8") });
            }
        }
    }
    walk(root);
    return out;
}