import { createHash } from "node:crypto";
import { generatePortableTypeScriptBindings, generateRemoteTypeScriptBindings } from "../bindings/portable.js";
import { type ExecutionPlan, ExecutionPlanError, hexDigest } from "./plan.js";
import { type ArtifactReader, type PackageArtifacts, type ArtifactGroup } from "./artifacts.js";
import { loadArtifactWorld, type LoadedArtifactWorld } from "./files.js";
import { componentAssetDeclarations } from "./client-contracts.js";

import { checkPackageBuildContract, packageBuildContract, type PackageBuildContract } from "./build-contract.js";

export interface GroupReceipt {
  schemaVersion: 1;
  packageRevisionId: string;
  bindingDigest: string;
  manifestDigest: string;
  generatorDigest: string;
  generated: { target: string; path: string; digest: string; bytes: number }[];
}
export interface ArtifactReceipt extends GroupReceipt {
  sourceDigest: string;
}
const hashBytes = (bytes: Uint8Array) => createHash("sha256").update(bytes).digest("hex");
/** Nominal identities never become filesystem paths. */
export const generatedBindingPath = (target: string) => `share/quixos/generated/target-${hexDigest(target)}.ts`;
/** Deterministic expected receipt. A trusted build must also typecheck and bundle these exact sources.
 * This is consistency evidence inside a trusted Nix build path, not remote build attestation. */
export function expectedArtifactReceipt(
  plan: ExecutionPlan,
  manifest: PackageArtifacts,
  generatorDigest: string,
): { receipt: ArtifactReceipt; sources: Map<string, Uint8Array> } {
  const pkg = plan.definition.packages.find((p) => p.revision === manifest.packageRevisionId);
  if (!pkg || manifest.sourceDigest !== pkg.sourceDigest)
    throw new ExecutionPlanError("INVALID_RECEIPT", manifest.packageRevisionId, "Receipt package/source mismatch");
  return expectedPackageReceipt(
    packageBuildContract(plan.definition.bindingSchema, pkg.revision),
    manifest,
    pkg.sourceDigest,
    generatorDigest,
  );
}
export function expectedPackageReceipt(
  contract: PackageBuildContract,
  manifest: PackageArtifacts,
  sourceDigest: string,
  generatorDigest: string,
): { receipt: ArtifactReceipt; sources: Map<string, Uint8Array> } {
  if (manifest.sourceDigest !== sourceDigest)
    throw new ExecutionPlanError("INVALID_RECEIPT", manifest.packageRevisionId, "Receipt source mismatch");
  const result = expectedGroupReceipt(contract, manifest, generatorDigest);
  return { ...result, receipt: { ...result.receipt, sourceDigest } };
}
export function expectedGroupReceipt(
  contract: PackageBuildContract,
  manifest: ArtifactGroup,
  generatorDigest: string,
): { receipt: GroupReceipt; sources: Map<string, Uint8Array> } {
  checkPackageBuildContract(contract);
  if (!/^[0-9a-f]{64}$/.test(generatorDigest)) throw new Error("Invalid trusted generator digest");
  const pkg = contract.definition.package;
  const schemaPackage = contract.definition.bindings.packages.find((p) => p.revisionId === pkg.revision)!;
  if (
    manifest.packageRevisionId !== pkg.revision ||
    manifest.bindingDigest !== contract.digest ||
    hexDigest(manifest.versions) !== hexDigest(contract.definition.versions)
  )
    throw new ExecutionPlanError("INVALID_RECEIPT", manifest.packageRevisionId, "Receipt package/contract mismatch");
  // A process service may implement transactions in any language. Only the
  // checked JS module path promises generated TypeScript adapter evidence.
  const available = new Set(
    manifest.implementations
      .filter(
        (i) =>
          i.compatibility === "quixos-js-module-v1" &&
          i.exports.some((id) => pkg.exports.some((entry) => entry.id === id && entry.execution.kind !== "remote")),
      )
      .map((i) => i.target),
  );
  const targets = [
    ...new Set(
      schemaPackage.exports.flatMap((e) => (e.execution && e.execution.kind !== "remote" ? e.execution.targets : [])),
    ),
  ]
    .filter((t) => available.has(t))
    .sort();
  const sources = new Map<string, Uint8Array>();
  const generated = targets.map((target) => {
    const path = generatedBindingPath(target);
    const bytes = new TextEncoder().encode(
      generatePortableTypeScriptBindings(contract.definition.bindings, pkg.revision, { target }),
    );
    sources.set(path, bytes);
    return { target, path, digest: hashBytes(bytes), bytes: bytes.length };
  });
  if (manifest.components?.length) {
    for (const [path, source] of [
      ["share/quixos/generated/client.ts", contract.definition.component!],
      ["share/quixos/generated/component-assets.d.ts", componentAssetDeclarations()],
    ] as const) {
      const bytes = new TextEncoder().encode(source);
      sources.set(path, bytes);
      generated.push({ target: "window", path, digest: hashBytes(bytes), bytes: bytes.length });
    }
  }
  // Custom language services need no TypeScript adapter. A checked JS module
  // exporting remote handlers does, and must carry the exact generated source.
  if (
    manifest.implementations.some(
      (implementation) =>
        implementation.compatibility === "quixos-js-module-v1" &&
        implementation.exports.some((id) =>
          pkg.exports.some((entry) => entry.id === id && entry.execution.kind === "remote"),
        ),
    )
  ) {
    const path = "share/quixos/generated/remote.ts";
    const bytes = new TextEncoder().encode(
      generateRemoteTypeScriptBindings(contract.definition.bindings, pkg.revision),
    );
    sources.set(path, bytes);
    generated.push({ target: "server", path, digest: hashBytes(bytes), bytes: bytes.length });
  }
  return {
    receipt: {
      schemaVersion: 1,
      packageRevisionId: pkg.revision,
      bindingDigest: contract.digest,
      manifestDigest: hexDigest(manifest),
      generatorDigest,
      generated,
    },
    sources,
  };
}
export async function checkArtifactReceipt(
  plan: ExecutionPlan,
  manifest: PackageArtifacts,
  receipt: unknown,
  generatorDigest: string,
  read: ArtifactReader,
): Promise<void> {
  const expected = expectedArtifactReceipt(plan, manifest, generatorDigest);
  if (hexDigest(receipt) !== hexDigest(expected.receipt))
    throw new ExecutionPlanError(
      "INVALID_RECEIPT",
      manifest.packageRevisionId,
      "Receipt differs from the trusted compiler/schema/artifact expectation",
    );
  for (const file of expected.receipt.generated) {
    const actual = await read(manifest.packageRevisionId, file.path, file.bytes);
    if (actual.length !== file.bytes || hashBytes(actual) !== file.digest)
      throw new ExecutionPlanError("INVALID_RECEIPT", file.path, "Generated bindings were replaced or omitted");
  }
}
/** Checked Nix builds validate generated sources with their selected compiler.
 * Runtime loading uses the stored outputs instead of repeating compilation. */
export async function loadCheckedArtifactWorld(
  plan: ExecutionPlan,
  roots: Readonly<Record<string, string>>,
  generatorDigest: string,
): Promise<LoadedArtifactWorld> {
  const loaded = await loadArtifactWorld(plan, roots);
  for (const manifest of loaded.manifests) {
    const bytes = await loaded.read(manifest.packageRevisionId, "share/quixos/build-receipt.json", 16 * 1024 * 1024);
    const receipt: unknown = JSON.parse(new TextDecoder("utf-8", { fatal: true }).decode(bytes));
    await checkArtifactReceipt(plan, manifest, receipt, generatorDigest, loaded.read);
  }
  return loaded;
}