import { keepPreviousData, useInfiniteQuery, useQuery } from '@tanstack/react-query'
import { useDebounce, useIntersectionObserver } from '@uidotdev/usehooks'
import { Check, ChevronsUpDown, CircleAlert, Info } from 'lucide-react'
import { useEffect, useMemo, useRef, useState } from 'react'
import {
  Button,
  cn,
  Command_Shadcn_,
  CommandGroup_Shadcn_,
  CommandInput_Shadcn_,
  CommandItem_Shadcn_,
  CommandList_Shadcn_,
  Popover_Shadcn_,
  PopoverContent_Shadcn_,
  PopoverTrigger_Shadcn_,
  ScrollArea,
  Tooltip,
  TooltipContent,
  TooltipTrigger,
} from 'ui'
import { ShimmeringLoader } from 'ui-patterns/ShimmeringLoader'

import { exposedFunctionCountsQueryOptions } from '@/data/privileges/exposed-function-counts-query'
import { exposedFunctionsInfiniteQueryOptions } from '@/data/privileges/exposed-functions-infinite-query'
import { useSelectedProjectQuery } from '@/hooks/misc/useSelectedProject'
import { pluralize } from '@/lib/helpers'

interface ExposedFunctionSelectorProps {
  disabled?: boolean
  selectedSchemas: string[]
  pendingAddFunctionNames: string[]
  pendingRemoveFunctionNames: string[]
  onTogglePendingAdd: (functionName: string) => void
  onTogglePendingRemove: (functionName: string) => void
}

export const ExposedFunctionSelector = ({
  disabled = false,
  selectedSchemas,
  pendingAddFunctionNames,
  pendingRemoveFunctionNames,
  onTogglePendingAdd,
  onTogglePendingRemove,
}: ExposedFunctionSelectorProps) => {
  const [open, setOpen] = useState(false)
  const [search, setSearch] = useState('')
  const debouncedSearch = useDebounce(search, 300)

  const { data: project } = useSelectedProjectQuery()

  const scrollRootRef = useRef<HTMLDivElement | null>(null)
  const [sentinelRef, entry] = useIntersectionObserver({
    root: scrollRootRef.current,
    threshold: 0,
    rootMargin: '0px',
  })

  const { data: countsData, isPending: isCountsPending } = useQuery({
    ...exposedFunctionCountsQueryOptions({
      projectRef: project?.ref,
      connectionString: project?.connectionString,
      selectedSchemas,
    }),
    placeholderData: keepPreviousData,
  })
  const pendingCount = pendingAddFunctionNames.length + pendingRemoveFunctionNames.length

  const totalCount = countsData?.total_count ?? 0
  const grantsCount = countsData?.grants_count ?? 0

  const { data, isPending, isError, isFetching, isFetchingNextPage, hasNextPage, fetchNextPage } =
    useInfiniteQuery({
      ...exposedFunctionsInfiniteQueryOptions({
        projectRef: project?.ref,
        connectionString: project?.connectionString,
        search: search.length === 0 ? undefined : debouncedSearch || undefined,
      }),
      placeholderData: search.length > 0 ? keepPreviousData : undefined,
    })

  const functions = useMemo(
    () => data?.pages.flatMap((page) => page.functions) ?? [],
    [data?.pages]
  )

  const pendingAddSet = useMemo(() => new Set(pendingAddFunctionNames), [pendingAddFunctionNames])
  const pendingRemoveSet = useMemo(
    () => new Set(pendingRemoveFunctionNames),
    [pendingRemoveFunctionNames]
  )

  useEffect(() => {
    if (!isPending && !isFetching && entry?.isIntersecting && hasNextPage && !isFetchingNextPage) {
      fetchNextPage()
    }
  }, [entry?.isIntersecting, hasNextPage, isFetching, isFetchingNextPage, isPending, fetchNextPage])

  return (
    <Popover_Shadcn_ open={open} onOpenChange={setOpen} modal={false}>
      <PopoverTrigger_Shadcn_ asChild>
        <Button
          size="small"
          disabled={disabled}
          type="default"
          className="w-full [&>span]:w-full pr-1! space-x-1"
          iconRight={<ChevronsUpDown className="text-foreground-muted" strokeWidth={2} size={14} />}
        >
          <div className="w-full flex gap-1">
            <p className="text-foreground-lighter">
              {isCountsPending
                ? 'Loading functions...'
                : totalCount === 0
                  ? 'No functions available'
                  : `${grantsCount} of ${totalCount} functions exposed${
                      pendingCount > 0
                        ? `, ${pendingCount} pending ${pluralize(pendingCount, 'change')}`
                        : ''
                    }`}
            </p>
          </div>
        </Button>
      </PopoverTrigger_Shadcn_>
      <PopoverContent_Shadcn_
        className="p-0 min-w-[200px] pointer-events-auto"
        side="bottom"
        align="start"
        sameWidthAsTrigger
      >
        <Command_Shadcn_ shouldFilter={false}>
          <CommandInput_Shadcn_
            className="text-xs"
            placeholder="Find function..."
            value={search}
            onValueChange={setSearch}
          />
          <CommandList_Shadcn_>
            <CommandGroup_Shadcn_>
              {isPending ? (
                <>
                  <div className="px-2 py-1">
                    <ShimmeringLoader className="py-2" />
                  </div>
                  <div className="px-2 py-1 w-4/5">
                    <ShimmeringLoader className="py-2" />
                  </div>
                </>
              ) : isError ? (
                <div className="flex items-center py-3 justify-center">
                  <p className="text-xs text-foreground-lighter">Failed to retrieve functions</p>
                </div>
              ) : (
                <>
                  {functions.length === 0 && (
                    <p className="text-xs text-center text-foreground-lighter py-3">
                      {search.length > 0 ? 'No functions found' : 'No functions available'}
                    </p>
                  )}
                  <ScrollArea
                    ref={scrollRootRef}
                    className={functions.length > 7 ? 'h-[210px]' : ''}
                  >
                    {functions.map((fn) => {
                      const key = `${fn.schema}.${fn.name}`
                      const isSchemaExposed = selectedSchemas.includes(fn.schema)
                      const hasPendingAdd = pendingAddSet.has(key)
                      const hasPendingRemove = pendingRemoveSet.has(key)

                      const isCustom = fn.status === 'custom'
                      const isGranted = fn.status === 'granted'

                      const isCustomNeutral = isCustom && !hasPendingAdd && !hasPendingRemove
                      const isExposed =
                        isSchemaExposed &&
                        (isCustom ? hasPendingAdd : isGranted ? !hasPendingRemove : hasPendingAdd)

                      const customGrantsTooltip = getCustomGrantsTooltip({
                        hasPendingAdd,
                        hasPendingRemove,
                      })

                      return (
                        <CommandItem_Shadcn_
                          key={key}
                          value={key}
                          className={cn(
                            'w-full',
                            isSchemaExposed ? 'cursor-pointer' : 'opacity-50 cursor-not-allowed!'
                          )}
                          onSelect={() => {
                            if (!isSchemaExposed) return

                            if (isCustom) {
                              if (hasPendingAdd) {
                                onTogglePendingAdd(key)
                                onTogglePendingRemove(key)
                              } else if (hasPendingRemove) {
                                onTogglePendingRemove(key)
                                onTogglePendingAdd(key)
                              } else {
                                onTogglePendingAdd(key)
                              }
                              return
                            }

                            if (isGranted) {
                              onTogglePendingRemove(key)
                            } else {
                              onTogglePendingAdd(key)
                            }
                          }}
                        >
                          <div className="w-full flex items-center gap-x-2">
                            <div className="w-4 shrink-0 flex items-center justify-center">
                              {isExposed && <Check size={16} className="text-brand shrink-0" />}
                              {!isSchemaExposed && (
                                <Tooltip>
                                  <TooltipTrigger asChild>
                                    <button
                                      type="button"
                                      tabIndex={-1}
                                      aria-label="Schema not exposed"
                                      className="inline-flex items-center text-foreground-muted hover:text-foreground-light"
                                    >
                                      <Info size={14} />
                                    </button>
                                  </TooltipTrigger>
                                  <TooltipContent side="left" className="max-w-[320px] text-xs">
                                    The schema "{fn.schema}" must be exposed before enabling this
                                    function.
                                  </TooltipContent>
                                </Tooltip>
                              )}
                            </div>
                            <span
                              className={cn(
                                'truncate',
                                (!isSchemaExposed || isCustomNeutral) && 'text-foreground-muted',
                                isCustomNeutral && isSchemaExposed && 'text-warning'
                              )}
                            >
                              {key}
                            </span>

                            <div className="ml-auto flex items-center gap-x-2">
                              {isCustom && (
                                <Tooltip>
                                  <TooltipTrigger asChild>
                                    <div
                                      className={cn(
                                        'shrink-0 flex items-center justify-center hover:text-foreground-light',
                                        isCustomNeutral && isSchemaExposed
                                          ? 'text-warning'
                                          : 'text-foreground-muted'
                                      )}
                                    >
                                      <CircleAlert size={14} />
                                    </div>
                                  </TooltipTrigger>
                                  <TooltipContent
                                    side="right"
                                    className="max-w-[320px] text-xs pointer-events-none"
                                  >
                                    {customGrantsTooltip}
                                  </TooltipContent>
                                </Tooltip>
                              )}
                            </div>
                          </div>
                        </CommandItem_Shadcn_>
                      )
                    })}
                    <div ref={sentinelRef} className="h-1 -mt-1" />
                    {hasNextPage && (
                      <div className="px-2 py-1">
                        <ShimmeringLoader className="py-2" />
                      </div>
                    )}
                  </ScrollArea>
                </>
              )}
            </CommandGroup_Shadcn_>
          </CommandList_Shadcn_>
        </Command_Shadcn_>
      </PopoverContent_Shadcn_>
    </Popover_Shadcn_>
  )
}

const getCustomGrantsTooltip = ({
  hasPendingAdd,
  hasPendingRemove,
}: {
  hasPendingAdd: boolean
  hasPendingRemove: boolean
}) => {
  if (hasPendingAdd) {
    return 'This function has custom grants. Saving will override them with standard Data API grants for anon, authenticated, and service_role. Select again to revoke all grants instead.'
  }

  if (hasPendingRemove) {
    return 'This function has custom grants. Saving will revoke all grants for anon, authenticated, and service_role. Select again to override with standard Data API grants instead.'
  }

  return 'This function has custom grants. Select it to override with standard Data API grants for anon, authenticated, and service_role.'
}