/** Shared prototype contracts. Browser handles never come from model output. */
export type BrowserAction = "click" | "fill";

export interface Candidate {
  id: string;
  role: string;
  name: string;
  actions: BrowserAction[];
}

export interface Observation {
  observationId: string;
  url: string;
  title: string;
  candidates: Candidate[];
}

export type Postcondition =
  | { kind: "url"; value: string }
  | { kind: "text"; value: string };

export interface ActRequest {
  observationId: string;
  candidateId: string;
  action: BrowserAction;
  text?: string;
  /** Mandatory for clicks. Filling always verifies the actual field value. */
  postcondition?: Postcondition;
}

export interface ActResult {
  verified: boolean;
  evidence: string;
}

export interface BrowserBridge {
  observe(signal: AbortSignal): Promise<Observation>;
  /** Must revalidate the snapshot's tab/document/target immediately before mutation,
   * consume all old observations, and verify the outcome. Never retry a mutation. */
  act(request: ActRequest, signal: AbortSignal): Promise<ActResult>;
  /** Must terminate owned workers before releasing the caller's browser lane. */
  close(): Promise<void>;
}

export interface Step {
  instruction: string;
  action: BrowserAction;
  /** A literal is inserted exactly; compose asks the auxiliary model for new text. */
  text?: string;
  compose?: string;
  /** Reference to a credential supplied by the initiating session; never sent to JEV. */
  credential?: string;
  postcondition?: Postcondition;
}

export interface Decision {
  candidateId: string | null;
  confidence: number;
  model: string;
}

export interface DecisionInput {
  instruction: string;
  action: BrowserAction;
  observation: Observation;
}

export type CredentialSource = string | { env: string } | { file: string; key?: string };
export type CredentialBindings = Record<string, CredentialSource>;

export interface StepTrace {
  step: number;
  status: "verified" | "abstained" | "unverified" | "error";
  timingsMs: Record<string, number>;
  /** Always emitted by the controller; unknown forbids automatic retry. */
  mutationState?: "not_attempted" | "verified" | "unknown";
  candidateId?: string;
  confidence?: number;
  model?: string;
  evidence?: string;
}

export interface RunResult {
  status: "completed" | "stopped";
  reason: string;
  steps: StepTrace[];
  elapsedMs: number;
  /** True when a dispatched action lacks a verified outcome. Never blindly retry. */
  actionMayHaveExecuted?: boolean;
}

/**
 * Development contracts for the session-scoped runtime.  The prototype
 * BrowserBridge above remains the compatibility boundary for observe/act/close;
 * new workers should implement BrowserRuntime rather than adding ad-hoc CDP
 * methods to BrowserBridge.
 */
export type MutationState = "not_attempted" | "verified" | "unknown";

export type BrowserErrorCode =
  | "aborted"
  | "timeout"
  | "stale"
  | "policy_denied"
  | "invalid_request"
  | "no_tab"
  | "ambiguous_tab"
  | "browser_closed"
  | "unsupported"
  | "worker_failure";

/** Safe to serialize to a report. Never include a URL query/fragment, headers,
 * bodies, field values, page text, provider response, or raw exception. */
export interface BrowserErrorDetails {
  code: BrowserErrorCode;
  operation: BrowserRuntimeOperationName;
  phase: string;
  message: string;
  mutationState: MutationState;
  retry: "never" | "safe";
}

export class BrowserOperationError extends Error {
  readonly details: BrowserErrorDetails;
  override name = "BrowserOperationError";

  constructor(details: BrowserErrorDetails) {
    super(details.message);
    this.details = details;
  }
}

/** Fixed budgets: implementations may choose a lower internal deadline, but
 * no caller-supplied generic timeout may exceed these ceilings. */
export const FAST_BROWSER_BUDGETS = {
  browserStartupMs: { default: 10_000, hardCeiling: 10_000 },
  workerReadyMs: { default: 5_000, hardCeiling: 5_000 },
  bridgeRequestMs: { default: 10_000, hardCeiling: 120_000 },
  actionVerificationMs: { default: 3_000, hardCeiling: 3_000 },
  readAssertionWaitMs: { default: 3_000, hardCeiling: 3_000 },
  navigationMs: { default: 10_000, hardCeiling: 10_000 },
  reloadMs: { default: 10_000, hardCeiling: 10_000 },
  popupWaitMs: { default: 5_000, hardCeiling: 5_000 },
  screenshotMs: { default: 10_000, hardCeiling: 60_000 },
  failureEvidenceMs: { default: 2_000, hardCeiling: 2_000 },
  runMs: { default: 60_000, hardCeiling: 120_000 },
} as const;

/** The session base policy is the existing '*' default or a non-empty exact
 * origin list. A runtime policy request may only narrow that base. */
export type RuntimeOriginPolicy = "*" | readonly string[];

/** Per-operation policy context. It is derived from the immutable session base
 * and is not a persistent cross-call mutation. Omit it to use the base. */
export interface RuntimeOperationContext {
  allowedOrigins: RuntimeOriginPolicy;
}

/** Opaque and stable for the life of a target; never model-created. */
export type BrowserTabId = string & { readonly __fastBrowserTabId: unique symbol };

export interface BrowserTab {
  tabId: BrowserTabId;
  kind: "page" | "popup";
  openerTabId?: BrowserTabId;
  selected: boolean;
  owned: true;
  /** Internal runtime value; public reports must reduce this to origin. */
  url: string;
  origin: string;
  title: string;
}

export interface ReadRequest {
  tabId?: BrowserTabId;
}

/** Read returns rendered visible text only. It never returns form values,
 * password values, hidden text, HTML, frames, or arbitrary script output. */
export interface PageRead {
  tab: BrowserTab;
  documentId: string;
  url: string;
  title: string;
  visibleText: string;
  visibleTextTruncated: boolean;
}

export type PageAssertion =
  | { kind: "url"; match: "exact" | "origin"; value: string }
  | { kind: "title"; match: "exact" | "contains"; value: string }
  | { kind: "visibleText"; match: "contains"; value: string };

export interface AssertRequest {
  tabId?: BrowserTabId;
  assertion: PageAssertion;
  /** "bounded" uses the fixed readAssertionWaitMs budget and performs no
   * mutation; "none" checks one read immediately. */
  wait: "none" | "bounded";
}

export interface AssertResult {
  status: "satisfied" | "not_satisfied" | "timed_out";
  readOnly: true;
  tab: BrowserTab;
  documentId: string;
}

export interface NavigateRequest {
  tabId?: BrowserTabId;
  /** HTTP(S), without credentials; destination origin must be approved. */
  url: string;
}

export interface NavigationResult {
  status: "committed";
  mutationState: "verified";
  tab: BrowserTab;
  documentId: string;
}

export interface ReloadRequest {
  tabId?: BrowserTabId;
}

export interface ReloadResult {
  status: "committed";
  mutationState: "verified";
  tab: BrowserTab;
  documentId: string;
}

export interface SelectTabRequest {
  tabId: BrowserTabId;
}

export interface SelectTabResult {
  selected: true;
  tab: BrowserTab;
}

export interface WaitPopupRequest {
  openerTabId: BrowserTabId;
}

export interface WaitPopupResult {
  status: "found" | "timed_out";
  /** A found popup is returned, but is never selected automatically. */
  tab?: BrowserTab;
  autoSwitched: false;
}

export interface CloseTabRequest {
  tabId: BrowserTabId;
}

export interface CloseTabResult {
  closed: true;
  tabId: BrowserTabId;
  mutationState: "verified";
}

export interface NarrowOriginPolicyRequest {
  allowedOrigins: RuntimeOriginPolicy;
}

export interface ConsoleFailureSummary {
  level: "error" | "warning";
  message: string;
  count: number;
  truncated: boolean;
}

/** Network evidence is deliberately origin-only: no query/fragment, headers,
 * cookies, request/response bodies, or field values. */
export interface NetworkFailureSummary {
  method: string;
  origin: string;
  status?: number;
  category: "http" | "network" | "blocked";
}

export type PrivateArtifactKind = "screenshot" | "diagnostics";

export interface PrivateArtifactOwner {
  sessionId: string;
  runId: string;
  operationId: string;
}

export interface PrivateArtifactMetadata {
  artifactId: string;
  kind: PrivateArtifactKind;
  contentType: "image/png" | "application/json";
  path: string;
  bytes: number;
  owner: PrivateArtifactOwner;
  permissions: "0600";
  localOnly: true;
  modelForwarded: false;
}

/** No caller-selected path: the store owns the path and commits atomically. */
export interface PrivateArtifactWriter {
  readonly owner: PrivateArtifactOwner;
  readonly kind: PrivateArtifactKind;
  write(chunk: Uint8Array): Promise<void>;
  commit(): Promise<PrivateArtifactMetadata>;
  abort(): Promise<void>;
}

export interface PrivateArtifactStore {
  open(owner: PrivateArtifactOwner, kind: PrivateArtifactKind): Promise<PrivateArtifactWriter>;
  close(): Promise<void>;
}

/** JSONL-safe worker-to-parent bytes. The parent decodes dataBase64 and writes
 * it through PrivateArtifactStore; worker requests never contain caller paths. */
export interface BrowserTransportArtifactPayload {
  kind: PrivateArtifactKind;
  contentType: "image/png" | "application/json";
  encoding: "base64";
  dataBase64: string;
  byteLength: number;
  truncated: boolean;
}

export interface BrowserTransportEvidence {
  status: "complete" | "partial" | "unavailable";
  screenshot?: BrowserTransportArtifactPayload;
  diagnostics?: BrowserTransportArtifactPayload;
  console: readonly ConsoleFailureSummary[];
  failedRequests: readonly NetworkFailureSummary[];
}

export const FAST_BROWSER_ARTIFACT_LIMITS = {
  screenshotBytes: 8 * 1024 * 1024,
  diagnosticsBytes: 256 * 1024,
} as const;

export const BROWSER_EVIDENCE_OPERATIONS = [
  "observe", "act", "read", "assert", "navigate", "reload", "listTabs",
  "selectTab", "waitPopup", "closeTab", "captureEvidence", "narrowOriginPolicy",
] as const;
export type BrowserEvidenceOperationName = (typeof BROWSER_EVIDENCE_OPERATIONS)[number];

export interface EvidenceRequest {
  /** Caller/scenario run identity; the runtime creates the operation identity. */
  runId: string;
  reason: "failure" | "requested";
  operation?: BrowserEvidenceOperationName;
}

export interface FailureEvidence {
  status: "complete" | "partial" | "unavailable";
  screenshot?: PrivateArtifactMetadata;
  diagnostics?: PrivateArtifactMetadata;
  console: readonly ConsoleFailureSummary[];
  failedRequests: readonly NetworkFailureSummary[];
}

/** A persistent per-session bridge. Different sessions may run in parallel;
 * all operations on one runtime are serialized. Tab handles/document identity
 * survive calls until the target/document is closed or navigated. */
export interface BrowserRuntime extends BrowserBridge {
  readonly sessionId: string;
  /** Computes one effective request policy; it never permanently tightens the
   * immutable session base. Pass the returned context to one or more calls in
   * the same explicitly scoped operation, or omit context to restore base. */
  narrowOriginPolicy(request: NarrowOriginPolicyRequest, signal: AbortSignal): Promise<RuntimeOperationContext>;
  observe(signal: AbortSignal, context?: RuntimeOperationContext): Promise<Observation>;
  act(request: ActRequest, signal: AbortSignal, context?: RuntimeOperationContext): Promise<ActResult>;
  read(request: ReadRequest, signal: AbortSignal, context?: RuntimeOperationContext): Promise<PageRead>;
  assert(request: AssertRequest, signal: AbortSignal, context?: RuntimeOperationContext): Promise<AssertResult>;
  navigate(request: NavigateRequest, signal: AbortSignal, context?: RuntimeOperationContext): Promise<NavigationResult>;
  reload(request: ReloadRequest, signal: AbortSignal, context?: RuntimeOperationContext): Promise<ReloadResult>;
  listTabs(signal: AbortSignal, context?: RuntimeOperationContext): Promise<readonly BrowserTab[]>;
  selectTab(request: SelectTabRequest, signal: AbortSignal, context?: RuntimeOperationContext): Promise<SelectTabResult>;
  waitPopup(request: WaitPopupRequest, signal: AbortSignal, context?: RuntimeOperationContext): Promise<WaitPopupResult>;
  closeTab(request: CloseTabRequest, signal: AbortSignal, context?: RuntimeOperationContext): Promise<CloseTabResult>;
  captureEvidence(request: EvidenceRequest, signal: AbortSignal, context?: RuntimeOperationContext): Promise<FailureEvidence>;
}

export interface BrowserRuntimeOptions {
  sessionId: string;
  cdpUrl: string;
  allowedOrigins: RuntimeOriginPolicy;
  /** Explicit interpreter selection for the pinned worker environment. */
  python?: string;
  artifacts: PrivateArtifactStore;
  /** Test/embedding seam; production may use the default transport factory. */
  transportFactory?: BrowserTransportFactory;
}

export interface BrowserRuntimeFactory {
  create(options: BrowserRuntimeOptions, parentSignal?: AbortSignal): BrowserRuntime;
}

/** The transport owns JSONL framing, validation, deadlines, and worker
 * teardown. BrowserRuntime owns persistent tab/policy state and delegates one
 * typed operation at a time; neither layer implements the other's boundary. */
export interface BrowserTransportRequest<Operation extends BrowserOperation = BrowserOperation> {
  operation: Operation;
  context?: RuntimeOperationContext;
}

export interface BrowserTransportCloseResult {
  closed: true;
}

/** Exact result mapping for every BrowserOperation variant. */
export type BrowserTransportResultFor<Operation extends BrowserOperation> =
  Operation extends { op: "observe" } ? { op: "observe"; result: Observation } :
  Operation extends { op: "act" } ? { op: "act"; result: ActResult } :
  Operation extends { op: "read" } ? { op: "read"; result: PageRead } :
  Operation extends { op: "assert" } ? { op: "assert"; result: AssertResult } :
  Operation extends { op: "navigate" } ? { op: "navigate"; result: NavigationResult } :
  Operation extends { op: "reload" } ? { op: "reload"; result: ReloadResult } :
  Operation extends { op: "listTabs" } ? { op: "listTabs"; result: readonly BrowserTab[] } :
  Operation extends { op: "selectTab" } ? { op: "selectTab"; result: SelectTabResult } :
  Operation extends { op: "waitPopup" } ? { op: "waitPopup"; result: WaitPopupResult } :
  Operation extends { op: "closeTab" } ? { op: "closeTab"; result: CloseTabResult } :
  Operation extends { op: "captureEvidence" } ? { op: "captureEvidence"; result: BrowserTransportEvidence } :
  Operation extends { op: "narrowOriginPolicy" } ? { op: "narrowOriginPolicy"; result: RuntimeOperationContext } :
  Operation extends { op: "close" } ? { op: "close"; result: BrowserTransportCloseResult } :
  never;

export type BrowserTransportResult = BrowserTransportResultFor<BrowserOperation>;

export interface BrowserTransport {
  dispatch<Operation extends BrowserOperation>(
    request: BrowserTransportRequest<Operation>,
    signal: AbortSignal,
  ): Promise<BrowserTransportResultFor<Operation>>;
  close(): Promise<void>;
}

export interface BrowserTransportOptions {
  cdpUrl: string;
  allowedOrigins: RuntimeOriginPolicy;
  python?: string;
}

export interface BrowserTransportFactory {
  create(options: BrowserTransportOptions, parentSignal?: AbortSignal): BrowserTransport;
}

export const BROWSER_RUNTIME_OPERATIONS = [
  "observe", "act", "read", "assert", "navigate", "reload", "listTabs",
  "selectTab", "waitPopup", "closeTab", "captureEvidence", "narrowOriginPolicy", "close",
] as const;
export type BrowserRuntimeOperationName = (typeof BROWSER_RUNTIME_OPERATIONS)[number];

/** Explicit JSONL/CLI operation shapes. There is no arbitrary CDP or JS arm. */
export type BrowserOperation =
  | { op: "observe" }
  | { op: "act"; request: ActRequest }
  | { op: "read"; request: ReadRequest }
  | { op: "assert"; request: AssertRequest }
  | { op: "navigate"; request: NavigateRequest }
  | { op: "reload"; request: ReloadRequest }
  | { op: "listTabs" }
  | { op: "selectTab"; request: SelectTabRequest }
  | { op: "waitPopup"; request: WaitPopupRequest }
  | { op: "closeTab"; request: CloseTabRequest }
  | { op: "captureEvidence"; request: EvidenceRequest }
  | { op: "narrowOriginPolicy"; request: NarrowOriginPolicyRequest }
  | { op: "close" };

/** Scenario references are data-only handles resolved by the CLI runner.
 * They cannot contain selectors, expressions, templates, CDP IDs, or JS. */
/** Scenario files are bounded to 32 operations by the CLI owner. */
export type ScenarioOperationIndex =
  | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7
  | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15
  | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23
  | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31;

export type ScenarioOperationRef =
  | { index: ScenarioOperationIndex }
  | { id: string };

/** Tab list indices are intentionally finite and bounded for JSON scenarios. */
export type ScenarioTabIndex = ScenarioOperationIndex;

/** Initial means the runtime's selected tab at scenario start. Operation
 * references must point to an earlier operation; the runner rejects forward
 * references and duplicate/unknown IDs. */
export type ScenarioTabReference =
  | { source: "initial"; target: "selected" }
  | {
      source: "operation";
      operation: ScenarioOperationRef;
      result: "selectedTab" | "popup";
    }
  | {
      source: "operation";
      operation: ScenarioOperationRef;
      result: "listedTab";
      index: ScenarioTabIndex;
    };

/** An origin selector must resolve to exactly one bounded listed tab. It never
 * changes the selected runtime tab by itself. */
export type ScenarioTabSelection =
  | { kind: "index"; index: ScenarioTabIndex }
  | { kind: "origin"; origin: string };

export interface ScenarioReadRequest {
  tab?: ScenarioTabReference;
}

export interface ScenarioAssertRequest {
  tab?: ScenarioTabReference;
  assertion: PageAssertion;
  wait: "none" | "bounded";
}

export interface ScenarioNavigateRequest {
  tab?: ScenarioTabReference;
  url: string;
}

export interface ScenarioReloadRequest {
  tab?: ScenarioTabReference;
}

export interface ScenarioListTabsRequest {
  /** Lists deterministically and optionally identifies one unique result;
   * selection still requires a later explicit selectTab operation. */
  select?: ScenarioTabSelection;
}

export interface ScenarioSelectTabRequest {
  tab: ScenarioTabReference;
}

export interface ScenarioWaitPopupRequest {
  opener: ScenarioTabReference;
}

export interface ScenarioCloseTabRequest {
  tab: ScenarioTabReference;
}

export interface ScenarioOperationMetadata {
  /** Optional stable local reference for later ScenarioOperationRef{id}. */
  id?: string;
}

/** Scenarios reuse the existing bounded Step instead of inventing browser code. */
export type ScenarioOperation =
  | ({ op: "step"; step: Step } & ScenarioOperationMetadata)
  | ({ op: "read"; request: ScenarioReadRequest } & ScenarioOperationMetadata)
  | ({ op: "assert"; request: ScenarioAssertRequest } & ScenarioOperationMetadata)
  | ({ op: "navigate"; request: ScenarioNavigateRequest } & ScenarioOperationMetadata)
  | ({ op: "reload"; request: ScenarioReloadRequest } & ScenarioOperationMetadata)
  | ({ op: "listTabs"; request?: ScenarioListTabsRequest } & ScenarioOperationMetadata)
  | ({ op: "selectTab"; request: ScenarioSelectTabRequest } & ScenarioOperationMetadata)
  | ({ op: "waitPopup"; request: ScenarioWaitPopupRequest } & ScenarioOperationMetadata)
  | ({ op: "closeTab"; request: ScenarioCloseTabRequest } & ScenarioOperationMetadata);

export const FAST_BROWSER_SCENARIO_FILE_VERSION = 1 as const;
export const FAST_BROWSER_REPORT_VERSION = 1 as const;

export const FAST_BROWSER_SCENARIO_SERVER_BOUNDS = {
  readinessTimeoutMs: { default: 10_000, hardCeiling: 30_000 },
  readinessPollMs: { default: 100, hardCeiling: 1_000 },
  serverShutdownMs: { default: 5_000, hardCeiling: 10_000 },
} as const;

/** Existing scenario hooks use this same trusted argv/cwd/env-reference
 * shape. `start` is long-lived and is supervised until scenario finally; it is
 * not a setup/reset/cleanup hook and has no shell mode. */
export interface ScenarioProcessHook {
  command: string;
  args: string[];
  cwd?: string;
  env?: Record<string, string | { env: string }>;
  timeoutMs?: number;
}

export interface ScenarioHttpReadiness {
  /** GET-only HTTP(S) URL supplied by scenario/user config, never page data. */
  url: string;
  expectedStatus?: number;
  timeoutMs?: number;
}

export type ScenarioServerConfig =
  | {
      mode: "managed";
      start: ScenarioProcessHook;
      readiness: ScenarioHttpReadiness;
      shutdownTimeoutMs?: number;
    }
  | {
      mode: "external";
      readiness: ScenarioHttpReadiness;
    };

export interface ScenarioFixtureConfig {
  /** Explicit HTTP(S) fixture base URL; no credentials or page-derived URL. */
  baseUrl: string;
  server?: ScenarioServerConfig;
}

export interface ScenarioDefinition {
  version: typeof FAST_BROWSER_SCENARIO_FILE_VERSION;
  id: string;
  operations: readonly ScenarioOperation[];
  fixture?: ScenarioFixtureConfig;
}

export interface ScenarioOperationReport {
  index: number;
  op: ScenarioOperation["op"];
  status: "passed" | "failed" | "skipped";
  elapsedMs: number;
  mutationState: MutationState;
  error?: BrowserErrorDetails;
}

export interface ScenarioReport {
  version: typeof FAST_BROWSER_REPORT_VERSION;
  scenarioId: string;
  status: "passed" | "failed" | "skipped";
  elapsedMs: number;
  operations: readonly ScenarioOperationReport[];
  evidence: readonly PrivateArtifactMetadata[];
  cleanup: "complete" | "failed";
}