import { createContext, useContext, useRef } from 'react'
import { shallow } from 'zustand/shallow'
import { createWithEqualityFn } from 'zustand/traditional'
import type { PersistStoreProviderProps } from '../types.js'
import type { HeaderState, HeaderStore } from './types.js'

export const HeaderStoreContext = createContext<HeaderStore | null>(null)

export function HeaderStoreProvider({ children }: PersistStoreProviderProps) {
  const storeRef = useRef<HeaderStore>(null)
  if (!storeRef.current) {
    storeRef.current = createHeaderStore()
  }
  return (
    <HeaderStoreContext.Provider value={storeRef.current}>
      {children}
    </HeaderStoreContext.Provider>
  )
}

export function useHeaderStoreContext() {
  const useStore = useContext(HeaderStoreContext)
  if (!useStore) {
    throw new Error(
      `You forgot to wrap your component in <${HeaderStoreProvider.name}>.`
    )
  }
  return useStore
}

export function useHeaderStore<T>(
  selector: (state: HeaderState) => T,
  equalityCheck?: (objA: T, objB: T) => boolean
): T {
  const useStore = useHeaderStoreContext()
  return useStore(selector, equalityCheck)
}

// We use fixed position on the header when Widget is in Full Height layout.
// We do this to get it to work like the sticky header does in the other layout modes.
// As the header is position fixed its not in the document flow anymore.
// To prevent the remaining page content from appearing behind the header we need to
// pass the headers height so that the position of the page content can be adjusted
export function useHeaderHeight() {
  const [headerHeight] = useHeaderStore(
    (state) => [state.headerHeight],
    shallow
  )

  return {
    headerHeight,
  }
}

export function useSetHeaderHeight() {
  const [setHeaderHeight] = useHeaderStore(
    (state) => [state.setHeaderHeight],
    shallow
  )

  return {
    setHeaderHeight,
  }
}

export const createHeaderStore = () =>
  createWithEqualityFn<HeaderState>(
    (set, get) => ({
      headerHeight: 108, // a basic default height
      setAction: (element) => {
        set(() => ({
          element,
        }))
        return get().removeAction
      },
      setTitle: (title) => {
        set(() => ({
          title,
        }))
        return get().removeTitle
      },
      removeAction: () => {
        set(() => ({
          element: null,
        }))
      },
      removeTitle: () => {
        set(() => ({
          title: undefined,
        }))
      },
      setHeaderHeight: (headerHeight) => {
        set(() => ({
          headerHeight,
        }))
      },
    }),
    Object.is
  )