<template lang="pug">
.StylesEditor
  nav
    .nav-item(
      :data-active="state.cssTarget === 'sidebar'"
      @click="selectCssTarget('sidebar')") {{translate('styles.css_sidebar')}}
    .nav-item(
      :data-active="state.cssTarget === 'group'"
      @click="selectCssTarget('group')") {{translate('styles.css_group')}}
  .columns
    .vars
      section(
        v-for="group of state.groups"
        :key="group.id"
        :data-hidden="!group.vars?.length")
        .section-header
          h2 {{group.label}}
        StyleField(
          v-for="(cssVar, i) of group.vars"
          :key="cssVar.key"
          v-model:value="cssVar.value"
          :noSeparator="i === 0"
          :active="cssVar.active"
          :label="cssVar.label"
          :name="cssVar.name"
          :isColor="cssVar.isColor"
          :or="'---'"
          @update:value="setCSSVarDebounced(cssVar)"
          @change="setCSSVar(cssVar)"
          @toggle="toggleCSSVar(cssVar)")

    .css(ref="customCssEl"): .wrapper
      .editor-box
        textarea.editor(
          ref="cssEditorEl"
          v-model="state.customCSS"
          autocomplete="off"
          autocorrect="off"
          autocapitalize="off"
          spellcheck="false"
          @input.passive="onInput"
          @keydown="onKeyDown"
          @change="applyCssDebounced()")
        .placeholder(:data-hidden="!!state.customCSS") {{translate('styles.css_placeholder')}}
        .placeholder-note(:data-hidden="!!state.customCSS") {{translate('styles.css_selectors_instruction')}}

  .bottom-bar
    .btn(@click="resetCSSVars") {{translate('styles.reset_styles')}}
    a.btn(@click="SetupPage.copyDevtoolsUrl()") {{translate('settings.copy_devtools_url')}}
    .color-sample(:style="getColorSampleStyle()")
      input.color(
        type="color"
        :value="state.colorSampleValue"
        @input="onColorSampelInput")
      .value {{state.colorSampleValue}}
      .example
</template>

<script lang="ts" setup>
import { ref, reactive, onMounted, nextTick } from 'vue'
import { translate } from 'src/dict'
import { CustomCssTarget } from 'src/types'
import { Styles } from 'src/services/styles'
import { Permissions } from 'src/services/permissions'
import StyleField from '../../components/style-field.vue'
import { SETTINGS_OPTIONS } from 'src/defaults'
import { Settings } from 'src/services/settings'
import { SetupPage } from 'src/services/setup-page'

interface CssVar {
  active: boolean
  key: string
  value: string
  re: RegExp
  isColor: boolean
  label: string
  name: string
  weight: number
}

interface CssVarsGroup {
  id: string
  label: string
  vars: CssVar[]
  notIn?: CustomCssTarget
  match?: RegExp
}

const FIRST_LETTER_RE = /^\w/
const DASH_RE = /-/g

const customCssEl = ref<HTMLElement | null>(null)
const cssEditorEl = ref<HTMLTextAreaElement | null>(null)
const state = reactive({
  active: false,
  vars: [] as CssVar[],
  customCSS: '',
  cssTarget: 'sidebar' as CustomCssTarget,
  colorSampleValue: '#000000',
  groups: [
    { id: '--general-', label: 'General', vars: [], match: /^--(general|frame|toolbar)/ },
    { id: '--frame-', label: 'Frame colors', vars: [] },
    { id: '--toolbar-', label: 'Toolbar colors', vars: [] },
    { id: '--nav-', label: translate('styles.vars_group.nav'), vars: [] },
    { id: '--tabs-', label: translate('styles.vars_group.tabs'), vars: [] },
    { id: '--bookmarks-', label: translate('styles.vars_group.bookmarks'), vars: [] },
    { id: '--history-', label: 'History', vars: [] },
    { id: '--popup-', label: 'Popup', vars: [] },
    { id: '--ctx-menu-', label: translate('styles.vars_group.menu'), vars: [] },
    { id: '--slt-', label: 'Sub-list title', vars: [] },
    { id: '--search-', label: 'Search bar', vars: [] },
    { id: '--ntb-', label: 'New-tab bar', vars: [] },
    { id: '--notification-', label: 'Notification', vars: [] },
    { id: '--btn-', label: translate('styles.vars_group.buttons'), vars: [] },
    { id: '--scroll-', label: translate('styles.vars_group.scroll'), vars: [] },
    { id: '--d-', label: translate('styles.vars_group.animation'), vars: [] },
    { id: 'other', label: translate('styles.vars_group.other'), vars: [] },
  ] as CssVarsGroup[],
})

void (async function init(): Promise<void> {
  state.customCSS = await Styles.getCustomCSS(state.cssTarget)
  updateVars()
  saveToHistory(state.customCSS)
})()

onMounted(async () => {
  await loadVars()
  updateVars()
  recalcGroups(state.vars)
})

function getColorSampleStyle(): Record<string, string> {
  return { '--color': state.colorSampleValue }
}

function updateVars(): void {
  for (const v of state.vars) {
    const reResult = v.re.exec(state.customCSS)
    v.active = !!reResult
    if (reResult) v.value = reResult[1]
  }
}
let updateVarsTimeout: number | undefined
function updateVarsDebounced(): void {
  clearTimeout(updateVarsTimeout)
  updateVarsTimeout = setTimeout(() => updateVars(), 500)
}

function recalcGroups(vars: CssVar[]): void {
  const commonGroup = state.groups[state.groups.length - 1]

  for (const g of state.groups) {
    g.vars = []
  }

  for (const v of vars) {
    if (v.key.startsWith('--s-')) continue

    if (v.key.endsWith('bg')) v.weight = 1
    else if (v.key.endsWith('fg')) v.weight = 1
    else if (v.key.endsWith('border')) v.weight = 1
    else if (v.key.endsWith('color')) v.weight = 1
    else if (v.key.endsWith('accent')) v.weight = 1
    else if (v.key.endsWith('separator')) v.weight = 1
    else if (v.key.endsWith('shadow')) v.weight = 2

    const group = state.groups.find(g => {
      if (g.match) return g.match.test(v.key)
      return v.key.startsWith(g.id)
    })
    if (group) {
      let key = v.key
      key = key.replace(group.id, '')
      key = key.replace('--', '')
      key = key.replace(DASH_RE, ' ')
      key = key.replace('bg', 'background')
      key = key.replace('fg', 'foreground')
      key = key.replace('btn', 'button')
      v.label = key.replace(FIRST_LETTER_RE, c => c.toUpperCase())
      group.vars.push(v)
    } else {
      let key = v.key
      key = key.slice(2)
      key = key.replace(DASH_RE, ' ')
      key = key.replace('bg', 'background')
      key = key.replace('fg', 'foreground')
      key = key.replace('btn', 'button')
      v.label = key.replace(FIRST_LETTER_RE, c => c.toUpperCase())
      commonGroup.vars.push(v)
    }
  }

  for (const g of state.groups) {
    if (g.vars.length) {
      g.vars.sort((a, b) => a.weight - b.weight)
    }
  }
}

async function getRootStyles(
  target: 'sidebar' | 'group'
): Promise<CSSStyleDeclaration | undefined> {
  let shadowContainerEl = document.getElementById('shadows_container')
  if (shadowContainerEl) shadowContainerEl.remove()

  shadowContainerEl = document.createElement('div')
  shadowContainerEl.setAttribute('id', 'shadows_container')
  document.body.appendChild(shadowContainerEl)

  return new Promise(res => {
    if (!shadowContainerEl) return

    const shadow = shadowContainerEl.attachShadow({ mode: 'open' })
    const shadowedRootEl = document.createElement('div')
    shadowedRootEl.setAttribute('id', 'root')
    shadowedRootEl.setAttribute('data-theme', Settings.state.theme || 'proton')
    shadowedRootEl.setAttribute('data-animations', Settings.state.animationSpeed || 'fast')
    shadowedRootEl.setAttribute('data-density', Settings.state.density || 'default')
    shadowedRootEl.setAttribute('data-frame-color-scheme', Styles.reactive.frameColorScheme)
    shadowedRootEl.setAttribute('data-toolbar-color-scheme', Styles.reactive.toolbarColorScheme)
    shadowedRootEl.setAttribute('data-act-el-color-scheme', Styles.reactive.actElColorScheme)
    shadowedRootEl.setAttribute('data-popup-color-scheme', Styles.reactive.popupColorScheme)
    if (Styles.parsedTheme) Styles.applyThemeSrcVars(Styles.parsedTheme, shadowedRootEl)
    shadow.appendChild(shadowedRootEl)

    const shadowLinkEl = document.createElement('link')
    shadowLinkEl.onload = () => res(getComputedStyle(shadowedRootEl))
    shadowLinkEl.onerror = () => res(undefined)
    shadowLinkEl.setAttribute('rel', 'stylesheet')
    shadowLinkEl.setAttribute('href', `../themes/proton/${target}.css`)
    shadow.appendChild(shadowLinkEl)
  })
}

async function loadVars(): Promise<void> {
  const compStyle = await getRootStyles(state.cssTarget)
  if (!compStyle) return

  const props: CssVar[] = []
  for (const prop of compStyle) {
    if (!prop.startsWith('--')) continue
    if (prop === '--color') continue
    if (prop.startsWith('--settings-')) continue
    if (prop.startsWith('--s-')) continue
    const value = compStyle.getPropertyValue(prop).trim()
    const isColor = isValueColor(value)
    let name = prop
    const re = new RegExp(`#root\\.root \\{${prop}: (.+?);\\}`)
    props.push({ active: false, key: prop, value, re, isColor, label: prop, name, weight: 0 })
  }

  state.vars = props
}

function isValueColor(value: string): boolean {
  return (
    value.startsWith('#') ||
    value.startsWith('rgb') ||
    value.startsWith('hsl') ||
    value === 'transparent' ||
    value === 'white' ||
    value === 'black'
  )
}

function toggleCSSVar(cssVar: CssVar): void {
  cssVar.active = !cssVar.active

  const re = new RegExp(`#root\\.root \\{${cssVar.key}: (.*?);\\}`)

  if (cssVar.active) {
    const css = `#root.root {${cssVar.key}: ${cssVar.value};}`
    if (re.test(state.customCSS)) state.customCSS = state.customCSS.replace(re, css)
    else state.customCSS = css + '\n' + state.customCSS
  } else {
    state.customCSS = state.customCSS.replace(re, '')
    state.customCSS = state.customCSS.trim()
    const rootEl = document.getElementById('root')
    if (rootEl && !cssVar.value) {
      const compStyle = getComputedStyle(rootEl)
      const value = compStyle.getPropertyValue(cssVar.key)
      if (value) cssVar.value = value
    }
  }

  applyCssDebounced(0)
  saveToHistory(state.customCSS, 0)
}

function setCSSVar(cssVar: CssVar): void {
  cssVar.active = true

  const re = new RegExp(`#root\\.root \\{${cssVar.key}: (.*?);\\}`)
  const css = `#root.root {${cssVar.key}: ${cssVar.value};}`

  if (re.test(state.customCSS)) state.customCSS = state.customCSS.replace(re, css)
  else state.customCSS = css + '\n' + state.customCSS

  applyCssDebounced(0)
  saveToHistory(state.customCSS, 0)
}
let setCSSVarTimeout: number | undefined
function setCSSVarDebounced(cssVar: CssVar): void {
  clearTimeout(setCSSVarTimeout)
  setCSSVarTimeout = setTimeout(() => setCSSVar(cssVar), 500)
}

function resetCSSVars(): void {
  const rootEl = document.getElementById('root')
  const compStyle = rootEl ? getComputedStyle(rootEl) : null

  for (const v of state.vars) {
    if (v.active) toggleCSSVar(v)
    if (compStyle) {
      const value = compStyle.getPropertyValue(v.key)
      if (value) v.value = value
    }
  }
}

async function selectCssTarget(target: CustomCssTarget): Promise<void> {
  state.cssTarget = target
  state.customCSS = await Styles.getCustomCSS(target)
  await loadVars()
  updateVars()
  recalcGroups(state.vars)
  resetHistory()
  saveToHistory(state.customCSS)
}

/**
 * Handle input
 */
function onInput(e: Event): void {
  applyCssDebounced(1000)
  saveToHistory(state.customCSS, 1000)
  updateVarsDebounced()
}

function onKeyDown(e: KeyboardEvent): void {
  // Insert tab
  if (e.key === 'Tab') tab(e)

  // Comment / Uncomment
  if (e.key === '/' && e.ctrlKey) comment(e)

  // Undo / Redo
  if (e.code === 'KeyZ' && e.ctrlKey) undoRedo(e)
}

const TAB_STR = '	'
function tab(e: KeyboardEvent): void {
  e.preventDefault()
  if (!cssEditorEl.value) return

  const start = cssEditorEl.value.selectionStart
  const end = cssEditorEl.value.selectionEnd
  const rawSrcValue = cssEditorEl.value.value

  const preStr = rawSrcValue.slice(0, start)
  const postStr = rawSrcValue.slice(end)

  state.customCSS = preStr + TAB_STR + postStr

  nextTick(() => {
    if (cssEditorEl.value) {
      cssEditorEl.value.selectionStart = start + TAB_STR.length
      cssEditorEl.value.selectionEnd = cssEditorEl.value.selectionStart
    }
  })

  applyCssDebounced()
  saveToHistory(state.customCSS, 300)
}

const COMMENT_START = '/* '
const COMMENT_END = ' */'
function comment(e: KeyboardEvent): void {
  e.preventDefault()
  if (!cssEditorEl.value) return

  const start = cssEditorEl.value.selectionStart
  const end = cssEditorEl.value.selectionEnd
  const rawSrcValue = cssEditorEl.value.value

  let finalSelectionStart = start
  let lineStart = start
  let lineEnd = end - 1

  if (start === end) {
    lineStart = findPrevLineBreak(rawSrcValue, start)
    lineEnd = findNextLineBreak(rawSrcValue, start)
  }

  const preCommentStr = rawSrcValue.slice(0, lineStart)
  const commentStr = rawSrcValue.slice(lineStart, lineEnd + 1)
  const postCommentStr = rawSrcValue.slice(lineEnd + 1)

  // Uncomment
  if (commentStr.startsWith(COMMENT_START) && commentStr.endsWith(COMMENT_END)) {
    const uncommentedStr = commentStr.slice(
      COMMENT_START.length,
      commentStr.length - COMMENT_END.length
    )
    state.customCSS = preCommentStr + uncommentedStr + postCommentStr
    if (start - 3 < lineStart) {
      finalSelectionStart = start + (lineStart - start)
    } else if (start > lineEnd - 2) {
      finalSelectionStart = start + (lineEnd - start - 5)
    } else finalSelectionStart = start - 3
  }

  // Comment
  else {
    state.customCSS = preCommentStr + '/* ' + commentStr + ' */' + postCommentStr
    finalSelectionStart = start + 3
  }

  nextTick(() => {
    if (cssEditorEl.value) {
      cssEditorEl.value.selectionStart = finalSelectionStart
      cssEditorEl.value.selectionEnd = cssEditorEl.value.selectionStart
    }
  })

  applyCssDebounced()
  saveToHistory(state.customCSS, 0)
}

function findPrevLineBreak(text: string, index: number): number {
  if (index <= 0) return 0

  for (let i = index; i--; ) {
    const char = text[i]
    if (char === '\n' || char === '\r') return i + 1
  }

  return 0
}

function findNextLineBreak(text: string, index: number): number {
  if (index >= text.length) return text.length - 1

  for (let i = index; i < text.length; i++) {
    const char = text[i]
    if (char === '\n' || char === '\r') return i - 1
  }

  return text.length - 1
}

function undoRedo(e: KeyboardEvent): void {
  e.preventDefault()
  if (!cssEditorEl.value) return

  let newValue: HistoryEntry | undefined
  if (!e.shiftKey) newValue = historyUndo()
  else newValue = historyRedo()

  if (newValue) {
    const start = cssEditorEl.value.selectionStart
    state.customCSS = newValue.text
    nextTick(() => {
      if (cssEditorEl.value) {
        cssEditorEl.value.selectionStart = newValue?.cursor ?? start
        cssEditorEl.value.selectionEnd = newValue?.cursor ?? start
      }
    })
  }

  applyCssDebounced()
}

let applyTimeout: number | undefined
function applyCssDebounced(delay = 1000): void {
  clearTimeout(applyTimeout)
  applyTimeout = setTimeout(() => Styles.setCustomCSS(state.cssTarget, state.customCSS), delay)
}

function onColorSampelInput(e: Event): void {
  const target = e.target as HTMLInputElement
  state.colorSampleValue = target.value
  copyColorSampleDebounced()
}
let copyColorSampleTimeout: number | undefined
function copyColorSampleDebounced(): void {
  clearTimeout(copyColorSampleTimeout)
  copyColorSampleTimeout = setTimeout(() => {
    if (Permissions.reactive.clipboardWrite) navigator.clipboard.writeText(state.colorSampleValue)
  })
}

interface HistoryEntry {
  text: string
  cursor?: number
}

const HISTORY_LIMIT = 16
const HISTORY_WRITE_DELAY = 1000
let saveToHistoryTimeout: number | undefined
let history: HistoryEntry[] = []
let historyPosition = 0

function saveToHistory(text: string, delay = HISTORY_WRITE_DELAY): void {
  clearTimeout(saveToHistoryTimeout)
  saveToHistoryTimeout = setTimeout(() => {
    saveToHistoryTimeout = undefined

    if (history[0]?.text === text) return

    history.unshift({ text, cursor: cssEditorEl.value?.selectionStart })
    if (history.length > HISTORY_LIMIT) history.pop()

    historyPosition = 0
  }, delay)
}

function resetHistory(): void {
  history = []
  historyPosition = 0
}

function historyUndo(): HistoryEntry | undefined {
  if (!history.length) return

  if (saveToHistoryTimeout !== undefined) {
    clearTimeout(saveToHistoryTimeout)
    saveToHistoryTimeout = undefined
    history.unshift({ text: state.customCSS, cursor: cssEditorEl.value?.selectionStart })
  }

  const value = history[++historyPosition]
  if (historyPosition >= history.length) historyPosition = history.length - 1

  return value
}

function historyRedo(): HistoryEntry | undefined {
  clearTimeout(saveToHistoryTimeout)
  saveToHistoryTimeout = undefined

  const value = history[--historyPosition]
  if (historyPosition < 0) historyPosition = 0

  return value
}
</script>
