import type {
  PathSegment,
  PortableTextBlock,
  PortableTextChild,
  PortableTextObject,
  PortableTextTextBlock,
} from '@sanity/types'
import {isEqual} from 'lodash'
import {Element, Text, type Descendant, type Node} from 'slate'
import type {EditorSchema} from '../editor/editor-schema'

export const EMPTY_MARKDEFS: PortableTextObject[] = []

export const VOID_CHILD_KEY = 'void-child'

type Partial<T> = {
  [P in keyof T]?: T[P]
}

function keepObjectEquality(
  object: PortableTextBlock | PortableTextChild,
  keyMap: Record<string, PortableTextBlock | PortableTextChild>,
) {
  const value = keyMap[object._key]
  if (value && isEqual(object, value)) {
    return value
  }
  keyMap[object._key] = object
  return object
}

export function toSlateValue(
  value: PortableTextBlock[] | undefined,
  {schemaTypes}: {schemaTypes: EditorSchema},
  keyMap: Record<string, any> = {},
): Descendant[] {
  if (value && Array.isArray(value)) {
    return value.map((block) => {
      const {_type, _key, ...rest} = block
      const isPortableText = block && block._type === schemaTypes.block.name
      if (isPortableText) {
        const textBlock = block as PortableTextTextBlock
        let hasInlines = false
        const hasMissingStyle = typeof textBlock.style === 'undefined'
        const hasMissingMarkDefs = typeof textBlock.markDefs === 'undefined'
        const hasMissingChildren = typeof textBlock.children === 'undefined'

        const children = (textBlock.children || []).map((child) => {
          const {_type: cType, _key: cKey, ...cRest} = child
          // Return 'slate' version of inline object where the actual
          // value is stored in the `value` property.
          // In slate, inline objects are represented as regular
          // children with actual text node in order to be able to
          // be selected the same way as the rest of the (text) content.
          if (cType !== 'span') {
            hasInlines = true
            return keepObjectEquality(
              {
                _type: cType,
                _key: cKey,
                children: [
                  {
                    _key: VOID_CHILD_KEY,
                    _type: 'span',
                    text: '',
                    marks: [],
                  },
                ],
                value: cRest,
                __inline: true,
              },
              keyMap,
            )
          }
          // Original child object (span)
          return child
        })
        // Return original block
        if (
          !hasMissingStyle &&
          !hasMissingMarkDefs &&
          !hasMissingChildren &&
          !hasInlines &&
          Element.isElement(block)
        ) {
          // Original object
          return block
        }
        // TODO: remove this when we have a better way to handle missing style
        if (hasMissingStyle) {
          rest.style = schemaTypes.styles[0].name
        }
        return keepObjectEquality({_type, _key, ...rest, children}, keyMap)
      }
      return keepObjectEquality(
        {
          _type,
          _key,
          children: [
            {
              _key: VOID_CHILD_KEY,
              _type: 'span',
              text: '',
              marks: [],
            },
          ],
          value: rest,
        },
        keyMap,
      )
    }) as Descendant[]
  }
  return []
}

export function fromSlateValue(
  value: Descendant[],
  textBlockType: string,
  keyMap: Record<string, PortableTextBlock | PortableTextChild> = {},
): PortableTextBlock[] {
  return value.map((block) => {
    const {_key, _type} = block
    if (!_key || !_type) {
      throw new Error('Not a valid block')
    }
    if (
      _type === textBlockType &&
      'children' in block &&
      Array.isArray(block.children) &&
      _key
    ) {
      let hasInlines = false
      const children = block.children.map((child) => {
        const {_type: _cType} = child
        if ('value' in child && _cType !== 'span') {
          hasInlines = true
          const {
            value: v,
            _key: k,
            _type: t,
            __inline: _i,
            children: _c,
            ...rest
          } = child
          return keepObjectEquality(
            {...rest, ...v, _key: k as string, _type: t as string},
            keyMap,
          )
        }
        return child
      })
      if (!hasInlines) {
        return block as PortableTextBlock // Original object
      }
      return keepObjectEquality(
        {...block, children, _key, _type},
        keyMap,
      ) as PortableTextBlock
    }
    const blockValue = 'value' in block && block.value
    return keepObjectEquality(
      {_key, _type, ...(typeof blockValue === 'object' ? blockValue : {})},
      keyMap,
    ) as PortableTextBlock
  })
}

export function isEqualToEmptyEditor(
  children: Descendant[] | PortableTextBlock[],
  schemaTypes: EditorSchema,
): boolean {
  return (
    children === undefined ||
    (children && Array.isArray(children) && children.length === 0) ||
    (children &&
      Array.isArray(children) &&
      children.length === 1 &&
      Element.isElement(children[0]) &&
      children[0]._type === schemaTypes.block.name &&
      'style' in children[0] &&
      children[0].style === schemaTypes.styles[0].name &&
      !('listItem' in children[0]) &&
      Array.isArray(children[0].children) &&
      children[0].children.length === 1 &&
      Text.isText(children[0].children[0]) &&
      children[0].children[0]._type === 'span' &&
      !children[0].children[0].marks?.join('') &&
      children[0].children[0].text === '')
  )
}

export function findBlockAndIndexFromPath(
  firstPathSegment: PathSegment,
  children: (Node | Partial<Node>)[],
): [Element | undefined, number | undefined] {
  let blockIndex = -1
  const isNumber = Number.isInteger(Number(firstPathSegment))
  if (isNumber) {
    blockIndex = Number(firstPathSegment)
  } else if (children) {
    blockIndex = children.findIndex(
      (blk) =>
        Element.isElement(blk) && isEqual({_key: blk._key}, firstPathSegment),
    )
  }
  if (blockIndex > -1) {
    return [children[blockIndex] as Element, blockIndex]
  }
  return [undefined, -1]
}

export function findChildAndIndexFromPath(
  secondPathSegment: PathSegment,
  block: Element,
): [Element | Text | undefined, number] {
  let childIndex = -1
  const isNumber = Number.isInteger(Number(secondPathSegment))
  if (isNumber) {
    childIndex = Number(secondPathSegment)
  } else {
    childIndex = block.children.findIndex((child) =>
      isEqual({_key: child._key}, secondPathSegment),
    )
  }
  if (childIndex > -1) {
    return [block.children[childIndex] as Element | Text, childIndex]
  }
  return [undefined, -1]
}

export function getValueOrInitialValue(
  value: unknown,
  initialValue: PortableTextBlock[],
): PortableTextBlock[] | undefined {
  if (value && Array.isArray(value) && value.length > 0) {
    return value
  }
  return initialValue
}