import { createHash } from "node:crypto";
import { canonicalJson } from "../capability-model/evolution.js";
import { type ExecutionPlan, type PlanPackage, ExecutionPlanError, hexDigest, executionVersions } from "./plan.js";

export interface ArtifactFile {
  path: string;
  digest: string;
  bytes: number;
  mediaType: string;
}
export interface ArtifactImplementation {
  id: string;
  target: string;
  compatibility: "quixos-service-v1" | "quixos-js-module-v1";
  path: string;
  ports: "quixos-transaction-ports-v1";
  registryExport?: string;
  exports: string[];
  /** Every executable/imported local asset, including the entrypoint, must be declared. */
  files: ArtifactFile[];
  contentDigest: string;
}
export interface PackageArtifacts {
  schemaVersion: 1;
  packageRevisionId: string;
  bindingDigest: string;
  sourceDigest: string;
  versions: ExecutionPlan["definition"]["versions"];
  implementations: ArtifactImplementation[];
}
export interface ImplementationSelection {
  target: string;
  compatibility: ArtifactImplementation["compatibility"];
  /** Optional only when exactly one compatible implementation covers these exports. */
  id?: string;
  exports: readonly string[];
}
/** Select from a checked manifest; selection does not establish package trust or isolation.
 * Never resolve ambiguity by manifest order or silently substitute a requested implementation.
 */
export function selectArtifactImplementation(
  manifest: PackageArtifacts,
  selection: ImplementationSelection,
): ArtifactImplementation {
  const candidates = manifest.implementations.filter(
    (entry) =>
      (selection.id === undefined || entry.id === selection.id) &&
      entry.target === selection.target &&
      entry.compatibility === selection.compatibility &&
      selection.exports.every((id) => entry.exports.includes(id)),
  );
  if (candidates.length !== 1)
    throw new ExecutionPlanError(
      candidates.length ? "AMBIGUOUS_IMPLEMENTATION" : "IMPLEMENTATION_UNAVAILABLE",
      manifest.packageRevisionId,
      `${selection.id ?? "Select an explicit implementation ID"}: expected one ${selection.target}/${selection.compatibility} implementation covering the requested exports; found ${candidates.length}`,
    );
  return candidates[0]!;
}
export interface CheckedWorld {
  codec: "camino-world-v1";
  plan: string;
  artifacts: { binding: string; target: string; digest: string }[];
  versions: Record<string, string>;
}
const fail = (path: string, message: string): never => {
  throw new ExecutionPlanError("INVALID_ARTIFACT", path, message);
};
const object = (value: unknown, path: string): Record<string, unknown> => {
  if (!value || typeof value !== "object" || Array.isArray(value) || Object.getPrototypeOf(value) !== Object.prototype)
    fail(path, "Expected a plain JSON record");
  return value as Record<string, unknown>;
};
const keys = (record: Record<string, unknown>, required: string[], optional: string[], path: string) => {
  if (
    required.some((key) => !Object.hasOwn(record, key)) ||
    Object.keys(record).some((key) => ![...required, ...optional].includes(key))
  )
    fail(path, "Unexpected or missing fields");
};
const text = (value: unknown, path: string): string => {
  if (
    typeof value !== "string" ||
    !value.length ||
    value.length > 4096 ||
    value.includes("\0") ||
    Buffer.from(value, "utf8").toString("utf8") !== value
  )
    fail(path, "Expected bounded nonempty text");
  return value as string;
};
const digest = (value: unknown, path: string): string => {
  if (typeof value !== "string" || !/^[0-9a-f]{64}$/.test(value)) fail(path, "Expected SHA-256 hex");
  return value as string;
};
const array = (value: unknown, path: string): unknown[] => {
  if (!Array.isArray(value) || value.length > 10000) fail(path, "Expected a bounded array");
  return value as unknown[];
};
const unique = (values: string[], path: string) => {
  if (new Set(values).size !== values.length) fail(path, "Duplicate identities");
};
export function artifactPath(value: unknown): string {
  const path = text(value, "artifact path");
  if (
    path.startsWith("/") ||
    path.includes("\\") ||
    path.split("/").some((part) => !part || part === "." || part === "..") ||
    /[\u0000-\u001f\u007f?#%]/.test(path)
  )
    fail(path, "Expected a normalized relative artifact path");
  return path;
}
/** No self-reference: the digest covers ABI/export metadata and the digests of every declared file. */
export function implementationDigest(implementation: Omit<ArtifactImplementation, "contentDigest">): string {
  return hexDigest({
    ...implementation,
    exports: [...implementation.exports].sort(),
    files: [...implementation.files].sort((a, b) => (a.path < b.path ? -1 : a.path > b.path ? 1 : 0)),
  });
}
export function parsePackageArtifacts(value: unknown): PackageArtifacts {
  const record = object(value, "manifest");
  keys(
    record,
    ["schemaVersion", "packageRevisionId", "bindingDigest", "sourceDigest", "versions", "implementations"],
    [],
    "manifest",
  );
  if (record.schemaVersion !== 1) fail("manifest", "Unsupported artifact manifest version");
  const versions = object(record.versions, "versions");
  keys(versions, ["value", "reference", "ports", "crdt"], [], "versions");
  for (const [key, value] of Object.entries(versions)) text(value, `versions.${key}`);
  const implementations = array(record.implementations, "implementations").map(
    (value, index): ArtifactImplementation => {
      const path = `implementations[${index}]`,
        entry = object(value, path);
      keys(
        entry,
        ["id", "target", "compatibility", "path", "ports", "exports", "files", "contentDigest"],
        ["registryExport"],
        path,
      );
      if (entry.compatibility !== "quixos-service-v1" && entry.compatibility !== "quixos-js-module-v1")
        fail(path, "Unsupported artifact ABI");
      if (entry.ports !== "quixos-transaction-ports-v1") fail(path, "Unsupported transaction port ABI");
      if (
        entry.compatibility === "quixos-service-v1" &&
        (entry.target !== "server" || entry.registryExport !== undefined)
      )
        fail(path, "Service must target server and has no JS registry export");
      if (entry.compatibility === "quixos-js-module-v1") text(entry.registryExport, `${path}.registryExport`);
      const exports = array(entry.exports, `${path}.exports`).map((value) => text(value, `${path}.exports`));
      unique(exports, `${path}.exports`);
      const files = array(entry.files, `${path}.files`).map((value): ArtifactFile => {
        const file = object(value, `${path}.file`);
        keys(file, ["path", "digest", "bytes", "mediaType"], [], `${path}.file`);
        if (
          !Number.isSafeInteger(file.bytes) ||
          (file.bytes as number) < 0 ||
          (file.bytes as number) > 256 * 1024 * 1024
        )
          fail(path, "Artifact file exceeds size bound");
        return {
          path: artifactPath(file.path),
          digest: digest(file.digest, path),
          bytes: file.bytes as number,
          mediaType: text(file.mediaType, path),
        };
      });
      unique(
        files.map((file) => file.path),
        `${path}.files`,
      );
      const entryPath = artifactPath(entry.path);
      if (!files.some((file) => file.path === entryPath)) fail(path, "Entrypoint is not covered by the file manifest");
      const result: ArtifactImplementation = {
        id: text(entry.id, path),
        target: text(entry.target, path),
        compatibility: entry.compatibility as ArtifactImplementation["compatibility"],
        path: entryPath,
        ports: "quixos-transaction-ports-v1",
        exports: exports.sort(),
        files: files.sort((a, b) => (a.path < b.path ? -1 : a.path > b.path ? 1 : 0)),
        contentDigest: digest(entry.contentDigest, path),
        ...(entry.registryExport !== undefined ? { registryExport: entry.registryExport as string } : {}),
      };
      const { contentDigest, ...body } = result;
      if (implementationDigest(body) !== contentDigest) fail(path, "Implementation metadata digest mismatch");
      return result;
    },
  );
  unique(
    implementations.map((implementation) => implementation.id),
    "implementations",
  );
  return {
    schemaVersion: 1,
    packageRevisionId: text(record.packageRevisionId, "packageRevisionId"),
    bindingDigest: digest(record.bindingDigest, "bindingDigest"),
    sourceDigest: digest(record.sourceDigest, "sourceDigest"),
    versions: versions as unknown as PackageArtifacts["versions"],
    implementations,
  };
}
function checkCoverage(expected: PlanPackage, manifest: PackageArtifacts): void {
  if (expected.bindingDigest !== manifest.bindingDigest || expected.sourceDigest !== manifest.sourceDigest)
    fail(expected.revision, "Substituted binding schema or source revision");
  for (const implementation of manifest.implementations)
    for (const id of implementation.exports) {
      const entry = expected.exports.find((e) => e.id === id);
      if (!entry) fail(implementation.id, `Unknown export ${id}`);
      if (
        implementation.target !== "server" &&
        (!entry?.execution ||
          entry.execution.kind === "remote" ||
          !entry.execution.targets.includes(implementation.target))
      )
        fail(implementation.id, `Export ${id} does not promise target ${implementation.target}`);
    }
  for (const entry of expected.exports) {
    if (!manifest.implementations.some((i) => i.compatibility === "quixos-service-v1" && i.exports.includes(entry.id)))
      fail(expected.revision, `Missing service fallback for ${entry.id}`);
    if (entry.execution.kind !== "remote")
      for (const target of entry.execution.targets)
        if (
          !manifest.implementations.some(
            (i) =>
              i.target === target &&
              i.exports.includes(entry.id) &&
              (target === "server" || i.compatibility !== "quixos-service-v1"),
          )
        )
          fail(expected.revision, `Missing ${target} implementation for ${entry.id}`);
  }
}
export type ArtifactReader = (packageRevisionId: string, path: string, maxBytes: number) => Promise<Uint8Array>;
/** Caller supplies a reader confined to the resolved immutable package output, including symlink checks. */
export async function checkExecutionWorld(
  plan: ExecutionPlan,
  inputs: readonly unknown[],
  read: ArtifactReader,
): Promise<CheckedWorld> {
  if (canonicalJson(plan.definition.versions) !== canonicalJson(executionVersions))
    fail("world", "Unsupported plan codec versions");
  if (hexDigest(plan.definition) !== plan.digest) fail("plan", "Plan digest mismatch");
  const manifests = inputs.map(parsePackageArtifacts);
  unique(
    manifests.map((m) => m.packageRevisionId),
    "packages",
  );
  if (manifests.length !== plan.definition.packages.length) fail("world", "Package closure differs from plan");
  const artifacts: CheckedWorld["artifacts"] = [];
  for (const expected of plan.definition.packages) {
    const manifest =
      manifests.find((m) => m.packageRevisionId === expected.revision) ??
      fail(expected.revision, "Missing package artifact");
    checkCoverage(expected, manifest);
    if (canonicalJson(manifest.versions) !== canonicalJson(plan.definition.versions))
      fail(expected.revision, "Incompatible runtime codecs");
    const files = new Map<string, ArtifactFile>();
    for (const implementation of manifest.implementations) {
      for (const file of implementation.files) {
        const existing = files.get(file.path);
        if (existing && canonicalJson(existing) !== canonicalJson(file))
          fail(file.path, "Conflicting file descriptors");
        files.set(file.path, file);
      }
      artifacts.push({
        binding: JSON.stringify([expected.revision, implementation.id]),
        target: implementation.target,
        digest: implementation.contentDigest,
      });
    }
    for (const file of files.values()) {
      const bytes = await read(expected.revision, file.path, file.bytes);
      if (bytes.byteLength !== file.bytes || createHash("sha256").update(bytes).digest("hex") !== file.digest)
        fail(file.path, "Artifact bytes do not match the checked content digest");
    }
  }
  return {
    codec: "camino-world-v1",
    plan: plan.digest,
    artifacts: artifacts.sort((a, b) =>
      a.binding < b.binding ? -1 : a.binding > b.binding ? 1 : a.target < b.target ? -1 : a.target > b.target ? 1 : 0,
    ),
    versions: { ...plan.definition.versions },
  };
}
/** Node counterpart of replica-core worldDigest. The wire fixture checks cross-package agreement. */
export function checkedWorldDigest(world: CheckedWorld): string {
  const normalized = {
    ...world,
    artifacts: [...world.artifacts].sort((a, b) =>
      a.binding < b.binding ? -1 : a.binding > b.binding ? 1 : a.target < b.target ? -1 : a.target > b.target ? 1 : 0,
    ),
  };
  const json = canonicalJson(normalized),
    content = createHash("sha256").update(json).digest("hex");
  const components = ["camino-world-v1", content].map((text) => Buffer.from(text, "utf8"));
  const count = Buffer.alloc(4);
  count.writeUInt32BE(components.length);
  const pieces = [count];
  for (const bytes of components) {
    const length = Buffer.alloc(4);
    length.writeUInt32BE(bytes.length);
    pieces.push(length, bytes);
  }
  return createHash("sha256").update(Buffer.concat(pieces)).digest("hex");
}