// Copyright 2025 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

import * as SDK from '../../core/sdk/sdk.js';
import type * as Protocol from '../../generated/protocol.js';

// eslint-disable-next-line rulesdir/es-modules-import
import * as StackTrace from './stack_trace.js';
import {AsyncFragmentImpl, FragmentImpl, FrameImpl, StackTraceImpl} from './StackTraceImpl.js';
import {type FrameNode, type RawFrame, Trie} from './Trie.js';

/**
 * A stack trace translation function.
 *
 * Any implementation must return an array with the same length as `frames`.
 */
export type TranslateRawFrames = (frames: readonly RawFrame[], target: SDK.Target.Target) => Promise<
    Array<Array<Pick<StackTrace.StackTrace.Frame, 'url'|'uiSourceCode'|'name'|'line'|'column'|'missingDebugInfo'>>>>;

/**
 * The {@link StackTraceModel} is a thin wrapper around a fragment trie.
 *
 * We want to store stack trace fragments per target so a SDKModel is the natural choice.
 */
export class StackTraceModel extends SDK.SDKModel.SDKModel<unknown> {
  readonly #trie = new Trie();

  /** @returns the {@link StackTraceModel} for the target, or the model for the primaryPageTarget when passing null/undefined */
  static #modelForTarget(target: SDK.Target.Target|null|undefined): StackTraceModel {
    const model = (target ?? SDK.TargetManager.TargetManager.instance().primaryPageTarget())?.model(StackTraceModel);
    if (!model) {
      throw new Error('Unable to find StackTraceModel');
    }
    return model;
  }

  async createFromProtocolRuntime(stackTrace: Protocol.Runtime.StackTrace, rawFramesToUIFrames: TranslateRawFrames):
      Promise<StackTrace.StackTrace.StackTrace> {
    const translatePromises: Array<Promise<unknown>> = [];

    const fragment = this.#createFragment(stackTrace.callFrames);
    translatePromises.push(this.#translateFragment(fragment, rawFramesToUIFrames));

    const asyncFragments: AsyncFragmentImpl[] = [];
    const debuggerModel = this.target().model(SDK.DebuggerModel.DebuggerModel);
    if (debuggerModel) {
      for await (const {stackTrace: asyncStackTrace, target} of debuggerModel.iterateAsyncParents(stackTrace)) {
        const model = StackTraceModel.#modelForTarget(target);
        const asyncFragment = model.#createFragment(asyncStackTrace.callFrames);
        translatePromises.push(model.#translateFragment(asyncFragment, rawFramesToUIFrames));
        asyncFragments.push(new AsyncFragmentImpl(asyncStackTrace.description ?? '', asyncFragment));
      }
    }

    await Promise.all(translatePromises);

    return new StackTraceImpl(fragment, asyncFragments);
  }

  /** Trigger re-translation of all fragments with the provide script in their call stack */
  async scriptInfoChanged(script: SDK.Script.Script, translateRawFrames: TranslateRawFrames): Promise<void> {
    const translatePromises: Array<Promise<unknown>> = [];
    let stackTracesToUpdate = new Set<StackTraceImpl>();

    for (const fragment of this.#affectedFragments(script)) {
      // We trigger re-translation only for fragments of leaf-nodes. Any fragment along the ancestor-chain
      // is re-translated as a side-effect.
      // We just need to remember the stack traces of the skipped over fragments, so we can send the
      // UPDATED event also to them.
      if (fragment.node.children.length === 0) {
        translatePromises.push(this.#translateFragment(fragment, translateRawFrames));
      }
      stackTracesToUpdate = stackTracesToUpdate.union(fragment.stackTraces);
    }

    await Promise.all(translatePromises);

    for (const stackTrace of stackTracesToUpdate) {
      stackTrace.dispatchEventToListeners(StackTrace.StackTrace.Events.UPDATED);
    }
  }

  #createFragment(frames: RawFrame[]): FragmentImpl {
    return FragmentImpl.getOrCreate(this.#trie.insert(frames));
  }

  async #translateFragment(fragment: FragmentImpl, rawFramesToUIFrames: TranslateRawFrames): Promise<void> {
    const rawFrames = fragment.node.getCallStack().map(node => node.rawFrame).toArray();
    const uiFrames = await rawFramesToUIFrames(rawFrames, this.target());
    console.assert(rawFrames.length === uiFrames.length, 'Broken rawFramesToUIFrames implementation');

    let i = 0;
    for (const node of fragment.node.getCallStack()) {
      node.frames = uiFrames[i++].map(
          frame => new FrameImpl(
              frame.url, frame.uiSourceCode, frame.name, frame.line, frame.column, frame.missingDebugInfo));
    }
  }

  #affectedFragments(script: SDK.Script.Script): Set<FragmentImpl> {
    // 1. Collect branches with the matching script.
    const affectedBranches = new Set<FrameNode>();
    this.#trie.walk(null, node => {
      // scriptId has precedence, but if the frame does not have one, check the URL.
      if (node.rawFrame.scriptId === script.scriptId ||
          (!node.rawFrame.scriptId && node.rawFrame.url === script.sourceURL)) {
        affectedBranches.add(node);
        return false;
      }
      return true;
    });

    // 2. For each branch collect all the fragments.
    const fragments = new Set<FragmentImpl>();
    for (const branch of affectedBranches) {
      this.#trie.walk(branch, node => {
        if (node.fragment) {
          fragments.add(node.fragment);
        }
        return true;
      });
    }
    return fragments;
  }
}

SDK.SDKModel.SDKModel.register(StackTraceModel, {capabilities: SDK.Target.Capability.NONE, autostart: false});