/**
 * Copyright (c) Microsoft Corporation.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import type { ActionTraceEvent } from '@trace/trace';
import { SplitView } from '@web/components/splitView';
import * as React from 'react';
import { useAsyncMemo } from './helpers';
import './sourceTab.css';
import { StackTraceView } from './stackTrace';
import { CodeMirrorWrapper } from '@web/components/codeMirrorWrapper';
import type { SourceHighlight } from '@web/components/codeMirrorWrapper';
import type { SourceModel } from './modelUtil';

export const SourceTab: React.FunctionComponent<{
  action: ActionTraceEvent | undefined,
  sources: Map<string, SourceModel>,
  hideStackFrames?: boolean,
}> = ({ action, sources, hideStackFrames }) => {
  const [lastAction, setLastAction] = React.useState<ActionTraceEvent | undefined>();
  const [selectedFrame, setSelectedFrame] = React.useState<number>(0);

  React.useEffect(() => {
    if (lastAction !== action) {
      setLastAction(action);
      setSelectedFrame(0);
    }
  }, [action, lastAction, setLastAction, setSelectedFrame]);

  const source = useAsyncMemo<SourceModel>(async () => {
    const file = action?.stack?.[selectedFrame].file;
    if (!file)
      return { errors: [], content: undefined };
    const source = sources.get(file)!;
    if (source.content === undefined) {
      const sha1 = await calculateSha1(file);
      try {
        let response = await fetch(`sha1/src@${sha1}.txt`);
        if (response.status === 404)
          response = await fetch(`file?path=${file}`);
        source.content = await response.text();
      } catch {
        source.content = `<Unable to read "${file}">`;
      }
    }
    return source;
  }, [action, selectedFrame], { errors: [], content: 'Loading\u2026' });

  const targetLine = action?.stack?.[selectedFrame]?.line || 0;
  const highlight: SourceHighlight[] = source.errors.map(e => ({ type: 'error', line: e.location.line, message: e.error!.message }));
  highlight.push({ line: targetLine, type: 'running' });

  return <SplitView sidebarSize={200} orientation='horizontal' sidebarHidden={hideStackFrames}>
    <CodeMirrorWrapper text={source.content || ''} language='javascript' highlight={highlight} revealLine={targetLine} readOnly={true} lineNumbers={true} />
    <StackTraceView action={action} selectedFrame={selectedFrame} setSelectedFrame={setSelectedFrame} />
  </SplitView>;
};

export async function calculateSha1(text: string): Promise<string> {
  const buffer = new TextEncoder().encode(text);
  const hash = await crypto.subtle.digest('SHA-1', buffer);
  const hexCodes = [];
  const view = new DataView(hash);
  for (let i = 0; i < view.byteLength; i += 1) {
    const byte = view.getUint8(i).toString(16).padStart(2, '0');
    hexCodes.push(byte);
  }
  return hexCodes.join('');
}