import { useFlag } from 'common'
import { AlertTriangle, ChevronRight, Inbox } from 'lucide-react'
import { Badge, Button, cn } from 'ui'
import { GenericSkeletonLoader } from 'ui-patterns/ShimmeringLoader'

import type { AdvisorItem } from './AdvisorPanel.types'
import {
  advisorCategoryIcons,
  formatItemDate,
  getAdvisorItemSecondaryText,
  getAdvisorPanelItemDisplayTitle,
  severityBadgeVariants,
  severityColorClasses,
  severityLabels,
} from './AdvisorPanel.utils'
import { EmptyAdvisor } from './EmptyAdvisor'
import type { Notification } from '@/data/notifications/notifications-v2-query'
import type { AdvisorCategory, AdvisorSeverity } from '@/state/advisor-state'

const NoProjectNotice = () => {
  const isHealthAdvisorEnabled = useFlag('healthAdvisor')
  return (
    <div className="absolute top-28 px-6 flex flex-col items-center justify-center w-full gap-y-2">
      <Inbox className="text-foreground-muted" strokeWidth={1} />
      <div className="text-center">
        <p className="heading-default">Project required</p>
        <p className="text-foreground-light text-sm">
          {isHealthAdvisorEnabled
            ? 'Select a project to view its security, performance and health advisories'
            : 'Select a project to view its security and performance advisories'}
        </p>
      </div>
    </div>
  )
}

interface AdvisorPanelBodyProps {
  isLoading: boolean
  isError: boolean
  filteredItems: AdvisorItem[]
  categoryFilters: AdvisorCategory[]
  severityFilters: AdvisorSeverity[]
  onItemClick: (item: AdvisorItem) => void
  onClearFilters: () => void
  onShowHiddenItems: () => void
  hiddenItemsCount: number
  hasAnyFilters: boolean
  hasProjectRef?: boolean
  projectNameByRef?: ReadonlyMap<string, string>
}

export const AdvisorPanelBody = ({
  isLoading,
  isError,
  filteredItems,
  categoryFilters,
  severityFilters,
  onItemClick,
  onClearFilters,
  onShowHiddenItems,
  hiddenItemsCount,
  hasAnyFilters,
  hasProjectRef = true,
  projectNameByRef,
}: AdvisorPanelBodyProps) => {
  // Notifications are the only items that exist without a project, so the notice replaces
  // the list whenever the user has narrowed to categories that need one.
  const needsProject =
    categoryFilters.length > 0 && categoryFilters.every((category) => category !== 'messages')
  if (!hasProjectRef && needsProject) {
    return <NoProjectNotice />
  }

  if (isLoading) {
    return (
      <div>
        <GenericSkeletonLoader className="w-full p-4" />
      </div>
    )
  }

  if (isError) {
    return (
      <div className="h-full mx-4 flex flex-col items-center justify-center gap-y-2">
        <AlertTriangle className="text-destructive" />
        <div className="flex flex-col items-center justify-center">
          <h4 className="text-base font-normal text-foreground-light">Error loading advisories</h4>
          <p className="text-sm text-foreground-lighter">Please try again later.</p>
        </div>
      </div>
    )
  }

  if (filteredItems.length === 0) {
    return (
      <EmptyAdvisor
        categoryFilters={categoryFilters}
        hasFilters={hasAnyFilters}
        onClearFilters={onClearFilters}
      />
    )
  }

  return (
    <>
      <div className="flex flex-col">
        {filteredItems.map((item) => {
          const CategoryIcon = advisorCategoryIcons[item.category]
          const severityClass = severityColorClasses[item.severity]
          const isNotification = item.source === 'notification'
          const notification = isNotification ? (item.original as Notification) : null
          const isUnread = notification?.status === 'new'

          const primaryText = getAdvisorPanelItemDisplayTitle(item)
          const secondaryText = getAdvisorItemSecondaryText(item, projectNameByRef)
          const metadataText =
            secondaryText ?? (item.createdAt ? formatItemDate(item.createdAt) : undefined)
          // Date strings (e.g. "a few seconds ago") come from formatItemDate and
          // need sentence-case capitalisation; entity strings (lint / signal) don't.
          const metadataCapitalize = secondaryText === undefined && item.createdAt !== undefined

          return (
            <div key={`${item.source}-${item.id}`} className="border-b">
              <Button
                variant="text"
                className={cn(
                  'justify-start w-full block rounded-none h-auto py-3 px-4 hover:text-foreground',
                  isUnread && 'bg-surface-100/50'
                )}
                onClick={() => onItemClick(item)}
              >
                <div className="flex items-center justify-between gap-2">
                  <div className="flex items-center gap-3 overflow-hidden">
                    <CategoryIcon
                      size={16}
                      strokeWidth={1.5}
                      className={cn('shrink-0', severityClass)}
                    />
                    <div className="text-left flex flex-col gap-0.5 truncate flex-1 min-w-0">
                      <div className="truncate">{primaryText}</div>
                      {metadataText && (
                        <div className="flex items-center gap-1 text-xs text-foreground-light">
                          <span
                            className={cn('truncate', metadataCapitalize && 'capitalize-sentence')}
                          >
                            {metadataText}
                          </span>
                        </div>
                      )}
                    </div>
                  </div>
                  <div className="flex items-center gap-2 shrink-0">
                    {item.severity === 'critical' && (
                      <Badge variant={severityBadgeVariants[item.severity]}>
                        {severityLabels[item.severity]}
                      </Badge>
                    )}
                    <ChevronRight
                      size={16}
                      strokeWidth={1.5}
                      className="shrink-0 text-foreground-lighter"
                    />
                  </div>
                </div>
              </Button>
            </div>
          )
        })}
      </div>
      {severityFilters.length > 0 && hiddenItemsCount > 0 && (
        <div className="px-4 py-3">
          <Button variant="text" className="w-full" onClick={onShowHiddenItems}>
            Show {hiddenItemsCount} more issue{hiddenItemsCount !== 1 ? 's' : ''}
          </Button>
        </div>
      )}
    </>
  )
}