import { defineComponent, ref, watch, onMounted, h, PropType, VNode } from 'vue'

import {
  calculateClickValue,
  calculateLabelPosition,
  calculateMoveValue,
  calculateTooltipPosition,
  getLabelValue,
  getNearestValueIndex,
  getThumbSize,
  updateGradient,
  updateValue,
  validateValue,
} from './utils'

import type { Label, ThumbSize } from './types'

import { isRTL } from '../../utils'

const CRangeSlider = defineComponent({
  name: 'CRangeSlider',
  props: {
    /**
     * Enable or disable clickable labels in the Vue Range Slider.
     * When set to `true`, users can click on labels to adjust the slider's value directly, enhancing interactivity and user experience.
     */
    clickableLabels: {
      type: Boolean,
      default: true,
    },
    /**
     * Control the interactive state of the Vue Range Slider with the `disabled` prop.
     * Setting it to `true` will disable all slider functionalities, preventing user interaction and visually indicating a non-interactive state.
     */
    disabled: {
      type: Boolean,
      default: false,
    },
    /**
     * Define the minimum distance between slider handles using the `distance` prop in the Vue Range Slider.
     * This ensures that the handles maintain a specified separation, preventing overlap and maintaining clear value distinctions.
     */
    distance: {
      type: Number,
      default: 0,
    },
    /**
     * Add descriptive labels to your Vue Range Slider by providing an array of `labels`.
     * These labels enhance the slider's usability by clearly indicating key values and providing contextual information to users.
     */
    labels: {
      type: Array as PropType<Label[]>,
      default: () => [],
    },
    /**
     * Specify the maximum value for the Vue Range Slider with the `max` prop.
     * This determines the upper limit of the slider's range, enabling precise control over the highest selectable value.
     */
    max: {
      type: Number,
      default: 100,
    },
    /**
     * Set the minimum value for the Vue Range Slider using the `min` prop.
     * This defines the lower bound of the slider's range, allowing you to control the starting point of user selection.
     */
    min: {
      type: Number,
      default: 0,
    },
    /**
     * The default name for a value passed using v-model.
     */
    modelValue: [Number, Array] as PropType<number | number[]>,
    /**
     * Assign a `name` to the Vue Range Slider for form integration.
     * Whether using a single string or an array of strings, this prop ensures that the slider's values are correctly identified when submitting forms.
     */
    name: {
      type: [String, Array] as PropType<string | string[]>,
      default: '',
    },
    /**
     * Control the granularity of the Vue Range Slider by setting the `step` prop.
     * This defines the increment intervals between selectable values, allowing for precise adjustments based on your application's requirements.
     */
    step: {
      type: Number,
      default: 1,
    },
    /**
     * Toggle the visibility of tooltips in the Vue Range Slider with the `tooltips` prop.
     * When enabled, tooltips display the current value of the slider handles, providing real-time feedback to users.
     */
    tooltips: {
      type: Boolean,
      default: true,
    },
    /**
     * Customize the display format of tooltips in the Vue Range Slider using the `tooltipsFormat` function.
     * This allows you to format the tooltip values according to your specific requirements, enhancing the clarity and presentation of information.
     */
    tooltipsFormat: {
      type: Function as PropType<(value: number) => string | VNode>,
      default: null,
    },
    /**
     * Controls the visual representation of the slider's track. When set to `'fill'`, the track is dynamically filled based on the slider's value(s). Setting it to `false` disables the filled track.
     */
    track: {
      type: [Boolean, String],
      default: 'fill',
      validator: (value: boolean | string) => {
        return typeof value === 'boolean' || value === 'fill'
      },
    },
    /**
     * Set the current value(s) of the Vue Range Slider using the `value` prop.
     * Whether you're using a single value or an array for multi-handle sliders, this prop controls the slider's position and ensures it reflects the desired state.
     */
    value: {
      type: [Number, Array] as PropType<number | number[]>,
      default: () => [0],
    },
    /**
     * Orient the Vue Range Slider vertically by setting the `vertical` prop to `true`.
     * This changes the slider's layout from horizontal to vertical, providing a different aesthetic and fitting various UI designs.
     */
    vertical: {
      type: Boolean,
      default: false,
    },
  },
  emits: [
    'change',
    /**
     * Emit the new value whenever there’s a change event.
     */
    'update:modelValue',
  ],
  setup(props, { emit }) {
    const rangeSliderRef = ref<HTMLDivElement | null>(null)
    const inputsRef = ref<HTMLInputElement[]>([])
    const labelsContainerRef = ref<HTMLDivElement | null>(null)
    const labelsRef = ref<HTMLDivElement[]>([])
    const trackRef = ref<HTMLDivElement | null>(null)

    const currentValue = ref<number[]>(
      props.modelValue
        ? Array.isArray(props.modelValue)
          ? props.modelValue
          : [props.modelValue]
        : Array.isArray(props.value)
          ? props.value
          : [props.value],
    )
    const isDragging = ref(false)
    const _isRTL = ref(false)
    const dragIndex = ref(0)
    const thumbSize = ref<ThumbSize | null>()

    watch(
      () => props.value,
      (newVal) => {
        currentValue.value = Array.isArray(newVal) ? newVal : [newVal]
      },
    )

    watch(
      () => props.modelValue,
      (newVal) => {
        if (newVal !== undefined) {
          currentValue.value = Array.isArray(newVal) ? newVal : [newVal]
        }
      },
    )

    // Adjust labels container size based on labels
    onMounted(() => {
      const maxSize = Math.max(
        ...labelsRef.value.map((label) =>
          props.vertical ? label.offsetWidth : label.offsetHeight,
        ),
      )

      if (labelsContainerRef.value) {
        labelsContainerRef.value.style[props.vertical ? 'width' : 'height'] = `${maxSize}px`
      }

      if (rangeSliderRef.value) {
        _isRTL.value = isRTL(rangeSliderRef.value)
        thumbSize.value = getThumbSize(rangeSliderRef.value, props.vertical)
      }
    })

    watch(isDragging, (newVal) => {
      if (newVal) {
        globalThis.addEventListener('mousemove', handleMouseMove)
        globalThis.addEventListener('mouseup', handleMouseUp)
      } else {
        globalThis.removeEventListener('mousemove', handleMouseMove)
        globalThis.removeEventListener('mouseup', handleMouseUp)
      }
    })

    const updateNearestValue = (value: number) => {
      const nearestIndex = getNearestValueIndex(value, currentValue.value)
      const newCurrentValue = [...currentValue.value]
      newCurrentValue[nearestIndex] = validateValue(
        value,
        currentValue.value,
        props.distance,
        nearestIndex,
      )

      setTimeout(() => {
        if (inputsRef.value[nearestIndex]) {
          inputsRef.value[nearestIndex].focus()
        }
      }, 0)

      currentValue.value = newCurrentValue

      emit('change', newCurrentValue)
      emit('update:modelValue', newCurrentValue)
    }

    const handleInputChange = (event: Event, index: number) => {
      if (props.disabled) return

      const target = event.target as HTMLInputElement
      const value = Number(target.value)

      const newCurrentValue = updateValue(value, currentValue.value, props.distance, index)

      currentValue.value = newCurrentValue

      emit('change', newCurrentValue)
      emit('update:modelValue', newCurrentValue)
    }

    const handleInputsContainerMouseDown = (event: MouseEvent) => {
      if (!trackRef.value || event.button !== 0 || props.disabled) return

      const target = event.target as HTMLDivElement | HTMLInputElement
      if (!(target instanceof HTMLInputElement) && target !== trackRef.value) {
        return
      }

      const clickValue = calculateClickValue(
        event,
        trackRef.value,
        props.min,
        props.max,
        props.step,
        props.vertical,
        _isRTL.value,
      )

      const index = getNearestValueIndex(clickValue, currentValue.value)

      isDragging.value = true
      dragIndex.value = index
      updateNearestValue(clickValue)
    }

    const handleLabelClick = (event: MouseEvent, value: number) => {
      if (!props.clickableLabels || props.disabled || event.button !== 0) return

      updateNearestValue(value)
    }

    const handleMouseMove = (event: MouseEvent) => {
      if (!isDragging.value || !trackRef.value || props.disabled) return

      const moveValue = calculateMoveValue(
        event,
        trackRef.value,
        props.min,
        props.max,
        props.step,
        props.vertical,
        _isRTL.value,
      )

      const newCurrentValue = updateValue(
        moveValue,
        currentValue.value,
        props.distance,
        dragIndex.value,
      )

      currentValue.value = newCurrentValue

      emit('change', newCurrentValue)
      emit('update:modelValue', newCurrentValue)
    }

    const handleMouseUp = () => {
      isDragging.value = false
    }

    return () =>
      h(
        'div',
        {
          class: [
            'range-slider',
            {
              'range-slider-vertical': props.vertical,
              disabled: props.disabled,
            },
          ],
          ref: rangeSliderRef,
        },
        [
          h(
            'div',
            {
              class: 'range-slider-inputs-container',
              onMousedown: handleInputsContainerMouseDown,
            },
            [
              currentValue.value.map((value, index) => [
                h('input', {
                  class: 'range-slider-input',
                  type: 'range',
                  min: props.min,
                  max: props.max,
                  step: props.step,
                  value: value,
                  name: Array.isArray(props.name)
                    ? props.name[index]
                    : `${props.name || ''}-${index}`,
                  role: 'slider',
                  'aria-valuemin': props.min,
                  'aria-valuemax': props.max,
                  'aria-valuenow': value,
                  'aria-orientation': props.vertical ? 'vertical' : 'horizontal',
                  disabled: props.disabled,
                  onInput: (e: Event) => handleInputChange(e, index),
                  ref: (el) => {
                    inputsRef.value[index] = el as HTMLInputElement
                  },
                }),
                props.tooltips &&
                  h(
                    'div',
                    {
                      class: 'range-slider-tooltip',
                      ...(thumbSize.value && {
                        style: calculateTooltipPosition(
                          props.min,
                          props.max,
                          value,
                          thumbSize.value,
                          props.vertical,
                          _isRTL.value,
                        ),
                      }),
                    },
                    [
                      h('div', { class: 'range-slider-tooltip-inner' }, [
                        props.tooltipsFormat ? props.tooltipsFormat(value) : value,
                      ]),
                      h('div', { class: 'range-slider-tooltip-arrow' }),
                    ],
                  ),
              ]),
              h('div', {
                class: 'range-slider-track',
                ...(props.track && {
                  style: updateGradient(
                    props.min,
                    props.max,
                    currentValue.value,
                    props.vertical,
                    _isRTL.value,
                  ),
                }),
                ref: trackRef,
              }),
            ],
          ),
          Array.isArray(props.labels) &&
            props.labels.length > 0 &&
            h(
              'div',
              {
                class: 'range-slider-labels-container',
                ref: labelsContainerRef,
              },
              props.labels.map((label, index) => {
                const labelPosition = calculateLabelPosition(
                  props.min,
                  props.max,
                  props.labels,
                  label,
                  index,
                )
                const labelValue = getLabelValue(props.min, props.max, props.labels, label, index)
                const labelStyle = {
                  ...(props.vertical
                    ? { bottom: labelPosition }
                    : _isRTL.value
                      ? { right: labelPosition }
                      : { left: labelPosition }),
                  ...(typeof label === 'object' && 'style' in label ? label.style : {}),
                }

                return h(
                  'div',
                  {
                    class: [
                      'range-slider-label',
                      {
                        clickable: props.clickableLabels,
                      },
                      typeof label === 'object' && 'className' in label ? label.className : '',
                    ],
                    style: labelStyle,
                    onMousedown: (event) => handleLabelClick(event, labelValue),
                    key: index,
                    ref: (el) => {
                      labelsRef.value[index] = el as HTMLDivElement
                    },
                  },
                  typeof label === 'object' && 'label' in label ? label.label : label,
                )
              }),
            ),
        ],
      )
  },
})

export { CRangeSlider }