import { createHash } from "node:crypto";
import { writeFile } from "node:fs/promises";
import type { SerializedRoute } from "@suaveplan/api-types/sandbox-bridge";
import {
    WASM_COMPILER_CODES,
    WasmCompilerError,
} from "../error-codes/error-codes.js";

/** Inputs for {@link writeManifest}. */
export interface WriteManifestOptions {
    /** Absolute path the manifest will be written to. */
    readonly manifestPath: string;
    /** Routes captured by the route-extract probe. */
    readonly routes: readonly SerializedRoute[];
    /** Pre-Javy bundled JS source — hashed into `sourceDigest`. */
    readonly bundledJs: string;
    /** Upstream Javy version pinned by the wrapper that compiled. */
    readonly javyVersion: string;
    /** This compiler's package version. */
    readonly compilerVersion: string;
    /** RFC 3339 UTC timestamp; defaults to `new Date().toISOString()`. */
    readonly compiledAt?: string;
    /**
     * Caller-supplied filesystem writer — defaults to
     * `node:fs/promises#writeFile`. Tests inject a recorder.
     */
    readonly fsWrite?: (path: string, data: string) => Promise<void>;
}

/** The full manifest record shape. */
export interface CompiledPluginManifest {
    readonly routes: readonly SerializedRoute[];
    readonly abiVersion: string;
    readonly abiVariant: "wasi-stdio";
    readonly javyVersion: string;
    readonly compilerVersion: string;
    readonly compiledAt: string;
    readonly sourceDigest: string;
}

/** The current compiler ABI version — semver string. */
export const COMPILER_ABI_VERSION = "1.0.0" as const;

/**
 * Emit the `<basename>.wasm.json` sidecar. Refuses empty `routes`
 * with `WASM_COMPILER.MANIFEST_MISSING_ROUTES` — a routeless plugin
 * cannot route a single request through the bridge, so shipping the
 * artifact would be pointless.
 *
 * Returns the manifest record so the orchestrator can include it in
 * the compile result without re-reading from disk.
 */
export async function writeManifest(
    options: WriteManifestOptions
): Promise<CompiledPluginManifest> {
    if (options.routes.length === 0) {
        throw new WasmCompilerError(
            WASM_COMPILER_CODES.MANIFEST_MISSING_ROUTES,
            "error.wasm_compiler.manifest_missing_routes",
            {
                context: { manifestPath: options.manifestPath },
            }
        );
    }
    const sourceDigest = createHash("sha256")
        .update(options.bundledJs)
        .digest("hex");
    const compiledAt = options.compiledAt ?? new Date().toISOString();
    const manifest: CompiledPluginManifest = {
        routes: options.routes,
        abiVersion: COMPILER_ABI_VERSION,
        abiVariant: "wasi-stdio",
        javyVersion: options.javyVersion,
        compilerVersion: options.compilerVersion,
        compiledAt,
        sourceDigest,
    };
    const writer = options.fsWrite ?? defaultWriter;
    await writer(options.manifestPath, JSON.stringify(manifest, null, 2));
    return manifest;
}

async function defaultWriter(path: string, data: string): Promise<void> {
    await writeFile(path, data, "utf8");
}