/*
 * Copyright 2021 Google LLC
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA
 */

import { h, Component } from 'preact';
import {
  secondsUntilNext,
  formatDuration,
  formatClock
} from './intervalometer.js';
import {
  statusReadout,
  configValue,
  shutterSpeedSeconds,
  exposureControls,
  detectFocusControls
} from './config-utils.js';

/** @typedef {import('./settings.js').Prefs} Prefs */
/** @typedef {import('./intervalometer.js').SequenceState} SequenceState */

/**
 * Things worth knowing before you walk away from a running camera for two hours.
 *
 * @param {Prefs} prefs
 * @param {import('web-gphoto2').Config | undefined} config
 * @param {boolean} hasFolder
 */
function sequenceWarnings(prefs, config, hasFolder) {
  let warnings = [];

  let format = configValue(config, 'imageformat');
  let isRaw = typeof format === 'string' && /raw/i.test(format);
  // Rough per-frame cost on top of the exposure itself: mirror, card write and
  // the USB 2.0 transfer. A 450D clears a JPEG in about 2s and a RAW in about 6s.
  let overhead = isRaw ? 6 : 2.5;
  let exposure = prefs.bulbEnabled
    ? prefs.bulbSeconds
    : shutterSpeedSeconds(configValue(config, 'shutterspeed'));

  if (exposure !== undefined && exposure >= prefs.intervalSeconds) {
    warnings.push(
      `The exposure (${formatDuration(exposure)}) is longer than the ${
        prefs.intervalSeconds
      }s interval — every frame will run late.`
    );
  } else if (
    exposure !== undefined &&
    prefs.intervalSeconds < exposure + overhead
  ) {
    warnings.push(
      `A ${prefs.intervalSeconds}s interval is tight: ${
        isRaw ? String(format) : 'each frame'
      } needs roughly ${formatDuration(
        exposure + overhead
      )} to shoot and transfer. Expect late frames.`
    );
  }

  if (prefs.saveMode === 'folder' && !hasFolder) {
    warnings.push('No output folder chosen yet — pick one in Settings.');
  }

  if (prefs.saveMode === 'download' && !prefs.unlimited && prefs.shots > 20) {
    warnings.push(
      `${prefs.shots} separate downloads will be slow and noisy. Saving to a folder is much better for a run this long.`
    );
  }

  if (prefs.bulbEnabled) {
    warnings.push(
      'Bulb mode is on: frames stay on the camera card and will not be saved by the browser.'
    );
  }

  return warnings;
}

/**
 * @param {{
 *   state: SequenceState,
 *   prefs: Prefs,
 *   voiceSupported: boolean,
 *   onToggleVoice: () => void
 * }} props
 */
function SequenceStatus({ state, prefs, voiceSupported, onToggleVoice }) {
  let { phase, taken, total } = state;
  let { headline, detail } = sequenceSummary(state, prefs);
  let progress = total ? Math.min(1, taken / total) : 0;
  return h(
    'div',
    { class: `sequence-status phase-${phase}` },
    h(
      'div',
      { class: 'status-head' },
      h(
        'div',
        { class: 'status-text' },
        h('div', { class: 'headline' }, headline),
        h('div', { class: 'detail' }, detail)
      ),
      // Sits with the countdown it speaks, rather than crowding the button row.
      voiceSupported
        ? h(
            'button',
            {
              type: 'button',
              class: `voice-toggle ${prefs.voice ? 'on' : ''}`,
              onclick: onToggleVoice,
              title: prefs.voice
                ? 'Voice countdown on — click to mute'
                : 'Voice countdown off — click to speak the countdown before each frame'
            },
            prefs.voice ? '🔊' : '🔇'
          )
        : undefined
    ),
    total
      ? h(
          'div',
          { class: 'progress' },
          h('div', { class: 'bar', style: `width: ${progress * 100}%` })
        )
      : undefined,
    state.errors > 0 && phase !== 'failed'
      ? h('div', { class: 'detail warn-text' }, `${state.errors} frame(s) failed`)
      : undefined
  );
}

/**
 * A camera setting as a dropdown, with the round-trip to the body surfaced.
 *
 * Each change is a USB round-trip that takes the best part of a second, so the
 * control locks and shows a spinner rather than pretending it was instant and
 * then snapping back to the old value.
 *
 * @extends Component<{
 *   node: import('web-gphoto2').Config,
 *   label: string,
 *   setValue: (name: string, value: any) => Promise<void>
 * }, { pending: boolean }>
 */
class ConfigSelect extends Component {
  state = { pending: false };

  handleChange = async e => {
    let value = e.currentTarget.value;
    this.setState({ pending: true });
    try {
      await this.props.setValue(this.props.node.name, value);
    } finally {
      this.setState({ pending: false });
    }
  };

  render(
    /** @type {ConfigSelect['props']} */ { node, label },
    /** @type {ConfigSelect['state']} */ { pending }
  ) {
    // Callers only pass menu/radio nodes; the union type doesn't know that.
    let { choices = [], value } = /** @type {any} */ (node);
    let locked = node.readonly || pending;
    return h(
      'label',
      { class: 'field' },
      h(
        'span',
        null,
        label,
        pending ? h('span', { class: 'mini-spinner' }) : undefined
      ),
      h(
        'select',
        {
          value,
          disabled: locked,
          title: node.readonly
            ? `${label} is fixed by the camera in this mode`
            : undefined,
          onChange: this.handleChange
        },
        choices.map(choice => h('option', { key: choice, value: choice }, choice))
      )
    );
  }
}

/**
 * Shutter / aperture / ISO, straight on the home screen.
 *
 * @param {{
 *   config: import('web-gphoto2').Config | undefined,
 *   setValue: (name: string, value: any) => Promise<void>
 * }} props
 */
function ExposureControls({ config, setValue }) {
  let controls = exposureControls(config);
  if (!controls.length) return undefined;
  let allLocked = controls.every(c => c.node.readonly);
  let mode = configValue(config, 'autoexposuremode');

  return h(
    'div',
    { class: 'card' },
    h('h3', { class: 'card-title' }, 'Exposure'),
    h(
      'div',
      { class: 'field-grid tight' },
      controls.map(({ name, label, node }) =>
        h(ConfigSelect, { key: name, node, label, setValue })
      )
    ),
    allLocked
      ? h(
          'p',
          { class: 'notice' },
          `The camera is driving exposure itself${
            mode ? ` in ${mode}` : ''
          } — switch the mode dial to M to set these from here.`
        )
      : undefined
  );
}

/**
 * Focus, where the body supports driving it over PTP.
 *
 * @param {{
 *   config: import('web-gphoto2').Config | undefined,
 *   setValue: (name: string, value: any) => Promise<void>,
 *   livePreview: boolean
 * }} props
 */
function FocusControls({ config, setValue, livePreview }) {
  let { manual, autofocus, mode } = detectFocusControls(config);
  if (!manual && !autofocus) return undefined;

  // Three nudge sizes per direction, largest on the outside.
  let step = (choice, glyph, title) =>
    h(
      'button',
      {
        key: choice,
        type: 'button',
        class: 'focus-step',
        title,
        onclick: () => setValue(manual.name, choice)
      },
      glyph
    );

  return h(
    'div',
    { class: 'card' },
    h(
      'h3',
      { class: 'card-title' },
      'Focus',
      mode ? h('span', { class: 'card-title-note' }, String(mode.value)) : undefined
    ),
    h(
      'div',
      { class: 'focus-row' },
      manual
        ? h(
            'div',
            { class: 'focus-steps' },
            h('span', { class: 'focus-end' }, 'Near'),
            [...manual.near].reverse().map((choice, i) =>
              step(choice, '◀'.repeat(manual.near.length - i), `Focus nearer — ${choice}`)
            ),
            manual.far.map((choice, i) =>
              step(choice, '▶'.repeat(i + 1), `Focus further — ${choice}`)
            ),
            h('span', { class: 'focus-end' }, 'Far')
          )
        : undefined,
      autofocus
        ? h(
            'button',
            {
              type: 'button',
              class: 'secondary',
              title: 'Trigger autofocus',
              onclick: () => setValue(autofocus, true)
            },
            'AF'
          )
        : undefined
    ),
    manual && !livePreview
      ? h(
          'p',
          { class: 'notice warn' },
          '⚠ Canon bodies generally only accept focus commands with live view running — turn it back on in Settings.'
        )
      : undefined
  );
}

/**
 * The one-line description of where the sequence is up to. Shared by the status
 * card and the fullscreen preview overlay.
 *
 * @param {SequenceState} state
 * @param {Prefs} prefs
 * @returns {{ headline: string, detail: string }}
 */
export function sequenceSummary(state, prefs) {
  let { phase, taken, total } = state;
  let headline;
  let detail;

  switch (phase) {
    case 'delay':
      headline = `Starting in ${formatDuration(secondsUntilNext(state))}`;
      detail = 'Waiting out the start delay.';
      break;
    case 'waiting':
      headline = `Next frame in ${formatDuration(secondsUntilNext(state))}`;
      detail = `${taken} of ${total || '∞'} captured`;
      break;
    case 'capturing':
      headline = prefs.bulbEnabled
        ? `⏱ Bulb exposure — ${prefs.bulbSeconds}s`
        : '📸 Capturing…';
      detail = `${taken} of ${total || '∞'} captured`;
      break;
    case 'done':
      headline = '✅ Sequence complete';
      detail = `${taken} frame${taken === 1 ? '' : 's'} in ${formatDuration(
        (state.finishedAt - state.startedAt) / 1000
      )}`;
      break;
    case 'stopped':
      headline = '⏹ Stopped';
      detail = `${taken} frame${taken === 1 ? '' : 's'} captured`;
      break;
    case 'failed':
      headline = '❌ Sequence failed';
      detail = `${taken} captured, ${state.errors} failed`;
      break;
    default:
      headline = 'Ready';
      detail = 'Set an interval and press Start.';
  }

  return { headline, detail };
}

/**
 * The whole home-screen control column: interval timing, start/stop, progress,
 * and a running log. Camera settings deliberately live in the drawer instead.
 *
 * @param {{
 *   prefs: Prefs,
 *   setPref: (patch: Partial<Prefs>) => void,
 *   state: SequenceState,
 *   running: boolean,
 *   onStart: () => void,
 *   onStop: () => void,
 *   onSingleShot: () => void,
 *   singleShotStatus: string,
 *   config: import('web-gphoto2').Config | undefined,
 *   hasFolder: boolean,
 *   canCapture: boolean,
 *   log: { id: number, message: string, kind: string, at: number }[],
 *   voiceSupported: boolean,
 *   onToggleVoice: () => void,
 *   setValue: (name: string, value: any) => Promise<void>
 * }} props
 */
export function Home({
  prefs,
  setPref,
  state,
  running,
  onStart,
  onStop,
  onSingleShot,
  singleShotStatus,
  config,
  hasFolder,
  canCapture,
  log,
  voiceSupported,
  onToggleVoice,
  setValue
}) {
  let warnings = running ? [] : sequenceWarnings(prefs, config, hasFolder);
  let plannedSeconds = prefs.unlimited
    ? Infinity
    : prefs.startDelaySeconds + prefs.shots * prefs.intervalSeconds;
  // Whatever is now an editable control doesn't need repeating as a readout.
  let readout = statusReadout(
    config,
    exposureControls(config).map(c => c.name)
  );

  /** @param {(value: number) => Partial<Prefs>} toPatch */
  let numberHandler = toPatch => e => {
    let value = /** @type {HTMLInputElement} */ (e.currentTarget).valueAsNumber;
    if (Number.isFinite(value)) setPref(toPatch(value));
  };

  return h(
    'div',
    { id: 'home' },
    h(SequenceStatus, { state, prefs, voiceSupported, onToggleVoice }),

    h(
      'div',
      { class: 'card' },
      h(
        'div',
        { class: 'field-grid' },
        h(
          'label',
          { class: 'field' },
          h('span', null, 'Interval'),
          h(
            'div',
            { class: 'input-with-unit' },
            h('input', {
              type: 'number',
              min: '0.5',
              step: '0.5',
              value: prefs.intervalSeconds,
              disabled: running,
              onInput: numberHandler(v => ({
                intervalSeconds: Math.max(0.5, v)
              }))
            }),
            h('span', { class: 'unit' }, 'sec')
          )
        ),
        h(
          'label',
          { class: 'field' },
          h('span', null, 'Frames'),
          h(
            'div',
            { class: 'input-with-unit' },
            h('input', {
              type: 'number',
              min: '1',
              step: '1',
              value: prefs.shots,
              disabled: running || prefs.unlimited,
              onInput: numberHandler(v => ({ shots: Math.max(1, Math.round(v)) }))
            }),
            h(
              'label',
              { class: 'inline-check' },
              h('input', {
                type: 'checkbox',
                checked: prefs.unlimited,
                disabled: running,
                onChange: e =>
                  setPref({ unlimited: e.currentTarget.checked })
              }),
              ' ∞'
            )
          )
        ),
        h(
          'label',
          { class: 'field' },
          h('span', null, 'Start delay'),
          h(
            'div',
            { class: 'input-with-unit' },
            h('input', {
              type: 'number',
              min: '0',
              step: '1',
              value: prefs.startDelaySeconds,
              disabled: running,
              onInput: numberHandler(v => ({
                startDelaySeconds: Math.max(0, Math.round(v))
              }))
            }),
            h('span', { class: 'unit' }, 'sec')
          )
        )
      ),

      h(
        'p',
        { class: 'plan' },
        prefs.unlimited
          ? `Runs until you stop it, one frame every ${prefs.intervalSeconds}s.`
          : `${prefs.shots} frames over ${formatDuration(
              plannedSeconds
            )} — finishing around ${formatClock(
              Date.now() + plannedSeconds * 1000
            )}.`
      ),

      h(
        'div',
        { class: 'actions' },
        h(
          'button',
          {
            type: 'button',
            class: running ? 'danger big' : 'primary big',
            disabled: !canCapture,
            onclick: running ? onStop : onStart
          },
          running ? '⏹ Stop' : '▶ Start sequence'
        ),
        h(
          'button',
          {
            type: 'button',
            class: 'secondary',
            disabled: !canCapture || running || singleShotStatus !== 'idle',
            onclick: onSingleShot
          },
          singleShotStatus === 'busy' ? '⌛ Capturing…' : '📷 Single shot'
        )
      ),

      warnings.map(text =>
        h('p', { key: text, class: 'notice warn' }, '⚠ ', text)
      )
    ),

    h(ExposureControls, { config, setValue }),
    h(FocusControls, { config, setValue, livePreview: prefs.livePreview }),

    readout.length
      ? h(
          'div',
          { class: 'readout' },
          readout.map(({ label, value }) =>
            h(
              'div',
              { key: label, class: 'readout-item' },
              h('span', { class: 'readout-label' }, label),
              h('span', { class: 'readout-value' }, String(value))
            )
          )
        )
      : undefined,

    log.length
      ? h(
          'div',
          { class: 'log' },
          log.map(entry =>
            h(
              'div',
              { key: entry.id, class: `log-entry ${entry.kind}` },
              h('span', { class: 'log-time' }, formatClock(entry.at)),
              h('span', null, entry.message)
            )
          )
        )
      : undefined
  );
}