/**
 * @license Copyright 2021 The Lighthouse Authors. All Rights Reserved.
 * 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 {FunctionComponent} from 'preact';

import {FlowStepIcon, FlowStepThumbnail} from './common';
import {useLocalizedStrings} from './i18n/i18n';
import {getModeDescription, useFlowResult} from './util';

const SIDE_THUMBNAIL_HEIGHT = 80;
const MAIN_THUMBNAIL_HEIGHT = 120;

const HeaderThumbnail: FunctionComponent<{
  lhr: LH.Result,
  position: 'prev'|'next'|'main'
}> =
({lhr, position}) => {
  const height = position === 'main' ? MAIN_THUMBNAIL_HEIGHT : SIDE_THUMBNAIL_HEIGHT;
  return (
    <div className={`HeaderThumbnail HeaderThumbnail--${position}`}>
      <FlowStepThumbnail lhr={lhr} height={height}/>
      <div className="HeaderThumbnail__icon">
        <FlowStepIcon mode={lhr.gatherMode}/>
      </div>
    </div>
  );
};

export const Header: FunctionComponent<{hashState: LH.HashState}> =
({hashState}) => {
  const flowResult = useFlowResult();
  const {index} = hashState;

  const step = flowResult.steps[index];
  const prevStep = flowResult.steps[index - 1];
  const nextStep = flowResult.steps[index + 1];

  const strings = useLocalizedStrings();
  const modeDescription = getModeDescription(step.lhr.gatherMode, strings);

  return (
    <div className="Header">
      {
        prevStep && <>
          {
            flowResult.steps[index - 2] && <div className="Header__segment"/>
          }
          <div className="Header__prev-thumbnail">
            <HeaderThumbnail lhr={prevStep.lhr} position="prev"/>
            <div className="Header__segment"/>
          </div>
          <a
            className="Header__prev-title"
            href={`#index=${index - 1}`}
          >{prevStep.name}</a>
        </>
      }
      <div className="Header__current-thumbnail">
        <HeaderThumbnail lhr={step.lhr} position="main"/>
      </div>
      <div className="Header__current-title">
        {step.name}
        <div className="Header__current-description">
          {modeDescription}
        </div>
      </div>
      {
        nextStep && <>
          <div className="Header__next-thumbnail">
            <div className="Header__segment"/>
            <HeaderThumbnail lhr={nextStep.lhr} position="next"/>
          </div>
          <a
            className="Header__next-title"
            href={`#index=${index + 1}`}
          >{nextStep.name}</a>
          {
            flowResult.steps[index + 2] && <div className="Header__segment"/>
          }
        </>
      }
    </div>
  );
};