import {
  readCdpExecutionContextCreated,
  readCdpExecutionContextDestroyed,
  readCdpScriptParsed,
  selectCdpScriptFrame,
  type CdpContextFrameClaim,
} from "./CdpScriptContextFacts.js";
import type { CdpEvent } from "./CdpConnection.js";
import type { ElectronScriptFrameClaims } from "../domain/javascript/electronObservation.js";
import { jsonValueByteLength } from "../domain/jsonValueByteLength.js";
import { CDP_CAPTURE_SCRIPT_METADATA_LIMITS } from "./CdpCaptureEventTypes.js";
import { CdpCaptureCompleteness } from "./CdpCaptureCompleteness.js";

export interface ElectronScriptDraft {
  readonly scriptId: string;
  readonly rawUrl: string;
  readonly hash: string | null;
  readonly length: number | null;
  readonly isModule: boolean | null;
  readonly language: string | null;
  readonly frameId: string | null;
  readonly hasSourceUrl: boolean | null;
  readonly frameClaims: ElectronScriptFrameClaims;
}

/** Frame identity is retained separately from the document generation's admission. */
export type ElectronScriptFrameScope =
  | { readonly state: "authorized"; readonly frameId: string }
  | { readonly state: "excluded" }
  | { readonly state: "unknown"; readonly frameId: string | null };

/** Cumulative JSON bytes for this capture's retained draft array, starting at `[]`. */
export interface ElectronScriptMetadataRetention {
  bytes: number;
}

/** Retain script/frame metadata from passive Electron events. */
export const ingestElectronScriptEvent = (input: {
  readonly event: CdpEvent;
  readonly scripts: ElectronScriptDraft[];
  readonly executionContextFrames: Map<string, CdpContextFrameClaim>;
  readonly completeness: CdpCaptureCompleteness;
  readonly retention: ElectronScriptMetadataRetention;
}): void => {
  if (input.event.method === "Runtime.executionContextsCleared") {
    input.executionContextFrames.clear();
    return;
  }
  if (input.event.method === "Runtime.executionContextDestroyed") {
    const key = readCdpExecutionContextDestroyed(input.event.params).contextKey;
    if (key !== null) input.executionContextFrames.delete(key);
    return;
  }
  if (input.event.method === "Runtime.executionContextCreated") {
    retainExecutionContext(input.event, input.executionContextFrames);
    return;
  }
  if (input.event.method !== "Debugger.scriptParsed") return;
  const facts = readCdpScriptParsed(input.event.params);
  const scriptId = facts.scriptId;
  const rawUrl = facts.url;
  if (scriptId === undefined || scriptId === "") {
    input.completeness.exclude("scripts", "invalid_protocol_value");
    return;
  }
  if (rawUrl === undefined || rawUrl === "") {
    input.completeness.exclude("scripts", "unattributed_origin");
    return;
  }
  const contextFrame =
    facts.contextKey === null
      ? undefined
      : input.executionContextFrames.get(facts.contextKey);
  const attribution = selectCdpScriptFrame(facts.frameClaim, contextFrame);
  if (
    attribution.invalid ||
    attribution.conflicting ||
    facts.invalidHasSourceUrl
  )
    input.completeness.exclude("scripts", "invalid_protocol_value");
  const reportedFrame = facts.frameClaim.frameId;
  const script: ElectronScriptDraft = {
    scriptId,
    rawUrl,
    ...facts.metadata,
    frameId: attribution.frameId,
    frameClaims: {
      ...(reportedFrame === undefined
        ? {}
        : { script_event_frame_id: reportedFrame }),
      ...(contextFrame?.frameId === undefined
        ? {}
        : { execution_context_frame_id: contextFrame.frameId }),
    },
    hasSourceUrl: facts.hasSourceUrl,
  };
  const remaining =
    CDP_CAPTURE_SCRIPT_METADATA_LIMITS.retainedBytes - input.retention.bytes;
  const bytes =
    jsonValueByteLength({ ...script }, remaining) +
    (input.scripts.length > 0 ? 1 : 0);
  if (bytes > remaining) {
    input.completeness.exclude("scripts", "resource_budget_exhausted");
    return;
  }
  input.retention.bytes += bytes;
  input.scripts.push(script);
};

const retainExecutionContext = (
  event: CdpEvent,
  frames: Map<string, CdpContextFrameClaim>,
): void => {
  const facts = readCdpExecutionContextCreated(event.params);
  if (facts.contextKey === null) return;
  frames.set(facts.contextKey, facts.frameClaim);
};