import { times } from 'lodash'
import { convert } from 'chromatism'
import { rgb2hex, hex2rgb, rgba2css, getCssColor } from '../color_convert/color_convert.js'
import { getColors, DEFAULT_OPACITY } from '../theme_data/theme_data.service.js'

// While this is not used anymore right now, I left it in if we want to do custom
// styles that aren't just colors, so user can pick from a few different distinct
// styles as well as set their own colors in the future.

export const setStyle = (href, commit) => {
  /***
      What's going on here?
      I want to make it easy for admins to style this application. To have
      a good set of default themes, I chose the system from base16
      (https://chriskempson.github.io/base16/) to style all elements. They
      all have the base00..0F classes. So the only thing an admin needs to
      do to style Pleroma is to change these colors in that one css file.
      Some default things (body text color, link color) need to be set dy-
      namically, so this is done here by waiting for the stylesheet to be
      loaded and then creating an element with the respective classes.

      It is a bit weird, but should make life for admins somewhat easier.
  ***/
  const head = document.head
  const body = document.body
  body.classList.add('hidden')
  const cssEl = document.createElement('link')
  cssEl.setAttribute('rel', 'stylesheet')
  cssEl.setAttribute('href', href)
  head.appendChild(cssEl)

  const setDynamic = () => {
    const baseEl = document.createElement('div')
    body.appendChild(baseEl)

    let colors = {}
    times(16, (n) => {
      const name = `base0${n.toString(16).toUpperCase()}`
      baseEl.setAttribute('class', name)
      const color = window.getComputedStyle(baseEl).getPropertyValue('color')
      colors[name] = color
    })

    body.removeChild(baseEl)

    const styleEl = document.createElement('style')
    head.appendChild(styleEl)
    // const styleSheet = styleEl.sheet

    body.classList.remove('hidden')
  }

  cssEl.addEventListener('load', setDynamic)
}

export const applyTheme = (input, commit) => {
  const { rules, theme } = generatePreset(input)
  const head = document.head
  const body = document.body
  body.classList.add('hidden')

  const styleEl = document.createElement('style')
  head.appendChild(styleEl)
  const styleSheet = styleEl.sheet

  styleSheet.toString()
  styleSheet.insertRule(`body { ${rules.radii} }`, 'index-max')
  styleSheet.insertRule(`body { ${rules.colors} }`, 'index-max')
  styleSheet.insertRule(`body { ${rules.shadows} }`, 'index-max')
  styleSheet.insertRule(`body { ${rules.fonts} }`, 'index-max')
  body.classList.remove('hidden')

  // commit('setOption', { name: 'colors', value: htmlColors })
  // commit('setOption', { name: 'radii', value: radii })
  commit('setOption', { name: 'customTheme', value: input })
  commit('setOption', { name: 'colors', value: theme.colors })
}

const getCssShadow = (input, usesDropShadow) => {
  if (input.length === 0) {
    return 'none'
  }

  return input
    .filter(_ => usesDropShadow ? _.inset : _)
    .map((shad) => [
      shad.x,
      shad.y,
      shad.blur,
      shad.spread
    ].map(_ => _ + 'px').concat([
      getCssColor(shad.color, shad.alpha),
      shad.inset ? 'inset' : ''
    ]).join(' ')).join(', ')
}

const getCssShadowFilter = (input) => {
  if (input.length === 0) {
    return 'none'
  }

  return input
  // drop-shadow doesn't support inset or spread
    .filter((shad) => !shad.inset && Number(shad.spread) === 0)
    .map((shad) => [
      shad.x,
      shad.y,
      // drop-shadow's blur is twice as strong compared to box-shadow
      shad.blur / 2
    ].map(_ => _ + 'px').concat([
      getCssColor(shad.color, shad.alpha)
    ]).join(' '))
    .map(_ => `drop-shadow(${_})`)
    .join(' ')
}

export const generateColors = (themeData) => {
  const rawOpacity = Object.assign({ ...DEFAULT_OPACITY }, Object.entries(themeData.opacity || {}).reduce((acc, [k, v]) => {
    if (typeof v !== 'undefined') {
      acc[k] = v
    }
    return acc
  }, {}))

  const inputColors = themeData.colors || themeData

  const opacity = {
    ...rawOpacity,
    ...Object.entries(inputColors).reduce((acc, [k, v]) => {
      if (v === 'transparent') {
        acc[k] = 0
      }
      return acc
    }, {})
  }

  // Cycle one: just whatever we have
  const sourceColors = Object.entries(inputColors).reduce((acc, [k, v]) => {
    if (typeof v === 'object') {
      acc[k] = v
    } else {
      let value = v
      if (v === 'transparent') {
        // TODO: hack to keep rest of the code from complaining
        value = '#FF00FF'
      }
      acc[k] = hex2rgb(value)
    }
    return acc
  }, {})

  const isLightOnDark = convert(sourceColors.bg).hsl.l < convert(sourceColors.text).hsl.l
  const mod = isLightOnDark ? 1 : -1

  const colors = getColors(sourceColors, opacity, mod)

  // Inheriting opacities
  Object.entries(opacity).forEach(([ k, v ]) => {
    if (typeof v === 'undefined') return
    if (k === 'alert') {
      colors.alertError.a = v
      colors.alertWarning.a = v
      return
    }
    if (k === 'faint') {
      colors['faintLink'].a = v
      colors['panelFaint'].a = v
      colors['lightBgFaintText'].a = v
      colors['lightBgFaintLink'].a = v
    }
    if (k === 'bg') {
      colors['lightBg'].a = v
    }
    if (k === 'badge') {
      colors['badgeNotification'].a = v
      return
    }
    if (colors[k]) {
      colors[k].a = v
    } else {
      console.error('Wrong key ' + k)
    }
  })

  const htmlColors = Object.entries(colors)
    .reduce((acc, [k, v]) => {
      if (!v) return acc
      acc.solid[k] = rgb2hex(v)
      acc.complete[k] = typeof v.a === 'undefined' ? rgb2hex(v) : rgba2css(v)
      return acc
    }, { complete: {}, solid: {} })
  return {
    rules: {
      colors: Object.entries(htmlColors.complete)
        .filter(([k, v]) => v)
        .map(([k, v]) => `--${k}: ${v}`)
        .join(';')
    },
    theme: {
      colors: htmlColors.solid,
      opacity
    }
  }
}

export const generateRadii = (input) => {
  let inputRadii = input.radii || {}
  // v1 -> v2
  if (typeof input.btnRadius !== 'undefined') {
    inputRadii = Object
      .entries(input)
      .filter(([k, v]) => k.endsWith('Radius'))
      .reduce((acc, e) => { acc[e[0].split('Radius')[0]] = e[1]; return acc }, {})
  }
  const radii = Object.entries(inputRadii).filter(([k, v]) => v).reduce((acc, [k, v]) => {
    acc[k] = v
    return acc
  }, {
    btn: 4,
    input: 4,
    checkbox: 2,
    panel: 10,
    avatar: 5,
    avatarAlt: 50,
    tooltip: 2,
    attachment: 5
  })

  return {
    rules: {
      radii: Object.entries(radii).filter(([k, v]) => v).map(([k, v]) => `--${k}Radius: ${v}px`).join(';')
    },
    theme: {
      radii
    }
  }
}

export const generateFonts = (input) => {
  const fonts = Object.entries(input.fonts || {}).filter(([k, v]) => v).reduce((acc, [k, v]) => {
    acc[k] = Object.entries(v).filter(([k, v]) => v).reduce((acc, [k, v]) => {
      acc[k] = v
      return acc
    }, acc[k])
    return acc
  }, {
    interface: {
      family: 'sans-serif'
    },
    input: {
      family: 'inherit'
    },
    post: {
      family: 'inherit'
    },
    postCode: {
      family: 'monospace'
    }
  })

  return {
    rules: {
      fonts: Object
        .entries(fonts)
        .filter(([k, v]) => v)
        .map(([k, v]) => `--${k}Font: ${v.family}`).join(';')
    },
    theme: {
      fonts
    }
  }
}

export const generateShadows = (input) => {
  const border = (top, shadow) => ({
    x: 0,
    y: top ? 1 : -1,
    blur: 0,
    spread: 0,
    color: shadow ? '#000000' : '#FFFFFF',
    alpha: 0.2,
    inset: true
  })
  const buttonInsetFakeBorders = [border(true, false), border(false, true)]
  const inputInsetFakeBorders = [border(true, true), border(false, false)]
  const hoverGlow = {
    x: 0,
    y: 0,
    blur: 4,
    spread: 0,
    color: '--faint',
    alpha: 1
  }

  const shadows = {
    panel: [{
      x: 1,
      y: 1,
      blur: 4,
      spread: 0,
      color: '#000000',
      alpha: 0.6
    }],
    topBar: [{
      x: 0,
      y: 0,
      blur: 4,
      spread: 0,
      color: '#000000',
      alpha: 0.6
    }],
    popup: [{
      x: 2,
      y: 2,
      blur: 3,
      spread: 0,
      color: '#000000',
      alpha: 0.5
    }],
    avatar: [{
      x: 0,
      y: 1,
      blur: 8,
      spread: 0,
      color: '#000000',
      alpha: 0.7
    }],
    avatarStatus: [],
    panelHeader: [],
    button: [{
      x: 0,
      y: 0,
      blur: 2,
      spread: 0,
      color: '#000000',
      alpha: 1
    }, ...buttonInsetFakeBorders],
    buttonHover: [hoverGlow, ...buttonInsetFakeBorders],
    buttonPressed: [hoverGlow, ...inputInsetFakeBorders],
    input: [...inputInsetFakeBorders, {
      x: 0,
      y: 0,
      blur: 2,
      inset: true,
      spread: 0,
      color: '#000000',
      alpha: 1
    }],
    ...(input.shadows || {})
  }

  return {
    rules: {
      shadows: Object
        .entries(shadows)
      // TODO for v2.1: if shadow doesn't have non-inset shadows with spread > 0 - optionally
      // convert all non-inset shadows into filter: drop-shadow() to boost performance
        .map(([k, v]) => [
          `--${k}Shadow: ${getCssShadow(v)}`,
          `--${k}ShadowFilter: ${getCssShadowFilter(v)}`,
          `--${k}ShadowInset: ${getCssShadow(v, true)}`
        ].join(';'))
        .join(';')
    },
    theme: {
      shadows
    }
  }
}

export const composePreset = (colors, radii, shadows, fonts) => {
  return {
    rules: {
      ...shadows.rules,
      ...colors.rules,
      ...radii.rules,
      ...fonts.rules
    },
    theme: {
      ...shadows.theme,
      ...colors.theme,
      ...radii.theme,
      ...fonts.theme
    }
  }
}

export const generatePreset = (input) => composePreset(
  generateColors(input),
  generateRadii(input),
  generateShadows(input),
  generateFonts(input)
)

export const getThemes = () => {
  return window.fetch('/static/styles.json')
    .then((data) => data.json())
    .then((themes) => {
      return Promise.all(Object.entries(themes).map(([k, v]) => {
        if (typeof v === 'object') {
          return Promise.resolve([k, v])
        } else if (typeof v === 'string') {
          return window.fetch(v)
            .then((data) => data.json())
            .then((theme) => {
              return [k, theme]
            })
            .catch((e) => {
              console.error(e)
              return []
            })
        }
      }))
    })
    .then((promises) => {
      return promises
        .filter(([k, v]) => v)
        .reduce((acc, [k, v]) => {
          acc[k] = v
          return acc
        }, {})
    })
}

export const setPreset = (val, commit) => {
  return getThemes().then((themes) => {
    const theme = themes[val] ? themes[val] : themes['pleroma-dark']
    const isV1 = Array.isArray(theme)
    const data = isV1 ? {} : theme.theme

    if (isV1) {
      const bg = hex2rgb(theme[1])
      const fg = hex2rgb(theme[2])
      const text = hex2rgb(theme[3])
      const link = hex2rgb(theme[4])

      const cRed = hex2rgb(theme[5] || '#FF0000')
      const cGreen = hex2rgb(theme[6] || '#00FF00')
      const cBlue = hex2rgb(theme[7] || '#0000FF')
      const cOrange = hex2rgb(theme[8] || '#E3FF00')

      data.colors = { bg, fg, text, link, cRed, cBlue, cGreen, cOrange }
    }

    // This is a hack, this function is only called during initial load.
    // We want to cancel loading the theme from config.json if we're already
    // loading a theme from the persisted state.
    // Needed some way of dealing with the async way of things.
    // load config -> set preset -> wait for styles.json to load ->
    // load persisted state -> set colors -> styles.json loaded -> set colors
    if (!window.themeLoaded) {
      applyTheme(data, commit)
    }
  })
}