import { randomUUID } from "node:crypto";
import { ENGINE_VERSION, SCHEMA_VERSION, type GraphMode, type RuntimeContext, type TopologyGraph } from "./types.js";
import { shortHash } from "./hash.js";

const DEFAULT_VIEWPORT = { width: 1440, height: 1000 } as const;

export function defaultViewport(): { width: number; height: number } {
  return { ...DEFAULT_VIEWPORT };
}

export function buildRuntimeContext(storageState?: string): RuntimeContext {
  return {
    browserName: "chromium",
    viewport: defaultViewport(),
    locale: "en-US",
    timezoneId: null,
    authContext: storageState ? "storage_state" : "anonymous",
  };
}

export function buildEmptyGraph(args: {
  inputUrl: string;
  entryUrl: string;
  mode: GraphMode;
  storageState?: string;
}): TopologyGraph {
  const generatedAt = new Date().toISOString();
  const crawlSessionId = `crawl_${randomUUID()}`;
  const inputFingerprint = `input_${shortHash([
    args.inputUrl,
    args.mode,
    "risk-policy-v0.2",
    "normalization-v0.2",
    "locator-scoring-v0.2",
  ])}`;
  return {
    schemaVersion: SCHEMA_VERSION,
    metadata: {
      artifactVersion: "topology-graph-v0.2",
      inputUrl: args.inputUrl,
      entryUrl: args.entryUrl,
      generatedAt,
      engineVersion: ENGINE_VERSION,
      mode: args.mode,
      crawlSessionId,
      inputSeed: args.inputUrl,
      inputFingerprint,
      runtimeContext: buildRuntimeContext(args.storageState),
      site: {
        baseUrl: baseUrl(args.entryUrl),
        entryUrl: args.entryUrl,
      },
      riskPolicyVersion: "risk-policy-v0.2",
      normalizationRuleVersion: "normalization-v0.2",
      locatorScoringVersion: "locator-scoring-v0.2",
    },
    states: [],
    elements: [],
    edges: [],
    skippedActions: [],
    failedObservations: [],
  };
}

function baseUrl(value: string): string {
  try {
    const url = new URL(value);
    if (url.protocol === "file:") return url.protocol;
    return `${url.protocol}//${url.host}`;
  } catch {
    return "unknown";
  }
}