/**
 * MiniApp SDK v1 的声明性 Manifest 契约。
 *
 * 该模块只验证 Runtime 接受的声明，不加载 Bundle、不创建 DOM，也不授予任何能力。
 * Runtime、Inventory 和 Tool Router 共享它，避免各自解释 Manifest。
 */
import type { JsonObject } from "@/runtime/protocol/lineup-v1";

export type MiniAppKind = "system" | "bundled";
export type MiniAppToolHandling = "direct" | "interactive" | "launch" | "foreground" | "operation";

export type MiniAppToolTarget = Readonly<{
  app_scope: string;
  requires_foreground: boolean;
  restore_previous_focus: boolean;
}>;

export type MiniAppToolDescriptor = Readonly<{
  id: string;
  version: 1;
  handling: MiniAppToolHandling;
  target?: MiniAppToolTarget;
  input_schema: JsonObject;
  output_schema: JsonObject;
  permissions?: readonly string[];
  timeout_ms?: number;
}>;

export type MiniAppManifestV1 = Readonly<{
  app_scope: string;
  version: string;
  kind: MiniAppKind;
  tools: readonly MiniAppToolDescriptor[];
  subscriptions: readonly string[];
  requested_capabilities: readonly string[];
  host: Readonly<{
    min_version: string;
    surface_required: boolean;
  }>;
}>;

export type ManifestValidation =
  | Readonly<{ accepted: true }>
  | Readonly<{ accepted: false; code: "manifest_denied"; detail: string }>;

const APP_SCOPE = /^[a-z][a-z0-9-]{0,63}$/;
const TOOL_ID = /^[a-z][a-z0-9-]*(?:\.[a-z][a-z0-9-]*)+$/;
const SEMVER = /^\d+\.\d+\.\d+(?:-[0-9A-Za-z.-]+)?(?:\+[0-9A-Za-z.-]+)?$/;
const CAPABILITY = /^[a-z][a-z0-9._-]{0,63}$/;
const HANDLINGS = new Set<MiniAppToolHandling>(["direct", "interactive", "launch", "foreground", "operation"]);

/**
 * Checks only static, local rules. Policy and per-user capability approval are
 * intentionally deferred to Runtime, because a Manifest never grants access.
 */
export function validateMiniAppManifest(manifest: MiniAppManifestV1): ManifestValidation {
  if (!APP_SCOPE.test(manifest.app_scope)) return reject("app_scope must be a lowercase Runtime scope.");
  if (!SEMVER.test(manifest.version) || !SEMVER.test(manifest.host.min_version)) return reject("version and host.min_version must be semantic versions.");
  if (manifest.kind !== "system" && manifest.kind !== "bundled") return reject("kind must be system or bundled.");
  if (manifest.kind === "bundled" && manifest.host.surface_required !== true) return reject("bundled MiniApps require a restricted Surface.");
  if (!Array.isArray(manifest.tools) || !Array.isArray(manifest.subscriptions) || !Array.isArray(manifest.requested_capabilities)) return reject("manifest collections must be arrays.");
  if (!manifest.subscriptions.every(entry => typeof entry === "string" && entry.length > 0)) return reject("subscriptions must be non-empty strings.");
  if (!manifest.requested_capabilities.every(entry => CAPABILITY.test(entry))) return reject("requested capabilities contain an invalid identifier.");

  const toolIDs = new Set<string>();
  for (const tool of manifest.tools) {
    if (!TOOL_ID.test(tool.id) || toolIDs.has(tool.id)) return reject("tool IDs must be unique dotted identifiers.");
    toolIDs.add(tool.id);
    if (tool.version !== 1 || !HANDLINGS.has(tool.handling)) return reject("tool version or handling is invalid.");
    if (!isJsonObject(tool.input_schema) || !isJsonObject(tool.output_schema)) return reject("tool schemas must be JSON objects.");
    if (tool.permissions && !tool.permissions.every((permission: string) => manifest.requested_capabilities.includes(permission))) return reject("tool permissions must be declared by the manifest.");
    if (tool.timeout_ms !== undefined && (!Number.isInteger(tool.timeout_ms) || tool.timeout_ms <= 0)) return reject("tool timeout_ms must be a positive integer.");

    if (tool.handling === "interactive") {
      if (tool.target !== undefined) return reject("interactive Tools must not target a MiniApp.");
      if (tool.timeout_ms !== undefined) return reject("interactive Tools use interaction expiry, not tool timeout_ms.");
    } else if (!validTarget(tool.target)) {
      return reject("non-interactive Tools require a valid target.");
    }
  }

  return { accepted: true };
}

function validTarget(target: MiniAppToolTarget | undefined): target is MiniAppToolTarget {
  return Boolean(target
    && APP_SCOPE.test(target.app_scope)
    && typeof target.requires_foreground === "boolean"
    && typeof target.restore_previous_focus === "boolean");
}

function isJsonObject(value: unknown): value is JsonObject {
  return value !== null && typeof value === "object" && !Array.isArray(value);
}

function reject(detail: string): ManifestValidation {
  return { accepted: false, code: "manifest_denied", detail };
}