'use client'

import { useState } from 'react'
import { Card, CardContent, CardHeader, CardTitle } from '@/components/ui/card'
import { Button } from '@/components/ui/button'
import { Badge } from '@/components/ui/badge'
import { Progress } from '@/components/ui/progress'
import {
  Select,
  SelectContent,
  SelectItem,
  SelectTrigger,
  SelectValue,
} from '@/components/ui/select'
import {
  Users,
  Send,
  CheckCircle2,
  AlertCircle,
  Loader2,
} from 'lucide-react'
import { trpc } from '@/lib/trpc/client'
import { toast } from 'sonner'

const categoryLabels: Record<string, string> = {
  STARTUP: 'Startup',
  BUSINESS_CONCEPT: 'Business Concept',
  UNKNOWN: 'Unknown',
}

type RoundUserTrackerProps = {
  editionId: string
}

export function RoundUserTracker({ editionId }: RoundUserTrackerProps) {
  const [selectedRoundId, setSelectedRoundId] = useState<string | undefined>(undefined)

  const { data, isLoading } = trpc.dashboard.getRoundUserStats.useQuery(
    { editionId, roundId: selectedRoundId },
    { enabled: !!editionId, refetchInterval: 120_000 }
  )

  const utils = trpc.useUtils()
  const sendReminders = trpc.dashboard.sendAccountReminders.useMutation({
    onSuccess: (result) => {
      toast.success(`Sent ${result.sent} reminder${result.sent !== 1 ? 's' : ''}${result.failed > 0 ? `, ${result.failed} failed` : ''}`)
      utils.dashboard.getRoundUserStats.invalidate()
    },
    onError: (err) => {
      toast.error(`Failed to send reminders: ${err.message}`)
    },
  })
  const [sendingTarget, setSendingTarget] = useState<string | null>(null)

  if (isLoading || !data) return null

  const { rounds, byCategory } = data
  const effectiveRoundId = data.selectedRoundId

  // Don't render if no rounds at all
  if (rounds.length === 0) return null

  const totalProjects = byCategory.reduce((sum, c) => sum + c.total, 0)
  const totalActivated = byCategory.reduce((sum, c) => sum + c.accountsSet, 0)
  const totalPending = byCategory.reduce((sum, c) => sum + c.accountsNotSet, 0)

  const selectedRound = effectiveRoundId ? rounds.find(r => r.id === effectiveRoundId) : undefined

  const handleSendReminder = async (target: string, opts: { category?: 'STARTUP' | 'BUSINESS_CONCEPT' }) => {
    setSendingTarget(target)
    try {
      await sendReminders.mutateAsync({
        editionId,
        roundId: effectiveRoundId!,
        category: opts.category,
      })
    } finally {
      setSendingTarget(null)
    }
  }

  return (
    <Card>
      <CardHeader className="pb-3">
        <div className="flex items-center justify-between gap-2">
          <CardTitle className="flex items-center gap-2 text-base">
            <Users className="h-4 w-4 text-brand-blue" />
            Round User Tracker
          </CardTitle>
          {totalProjects > 0 && (
            <Badge variant="outline" className="text-xs shrink-0">
              {totalActivated}/{totalProjects} activated
            </Badge>
          )}
        </div>
        {/* Round selector */}
        <Select
          value={effectiveRoundId ?? ''}
          onValueChange={(val) => setSelectedRoundId(val)}
        >
          <SelectTrigger className="h-8 text-xs mt-2">
            <SelectValue placeholder="Select round" />
          </SelectTrigger>
          <SelectContent>
            {rounds.map((r) => (
              <SelectItem key={r.id} value={r.id} className="text-xs">
                {r.name}
                {r.status === 'ROUND_ACTIVE' && (
                  <span className="ml-1.5 text-emerald-600">(active)</span>
                )}
              </SelectItem>
            ))}
          </SelectContent>
        </Select>
      </CardHeader>
      <CardContent className="space-y-4">
        {totalProjects === 0 ? (
          <div className="text-center py-4">
            <Users className="h-8 w-8 text-muted-foreground/30 mx-auto mb-2" />
            <p className="text-sm text-muted-foreground">
              No projects have passed {selectedRound?.name ?? 'this round'} yet
            </p>
          </div>
        ) : (
        <>
        {/* Subtitle showing round context */}
        <p className="text-xs text-muted-foreground">
          Projects that passed <span className="font-medium">{selectedRound?.name ?? 'this round'}</span> — account activation status
        </p>

        {/* Per-category rows */}
        {byCategory.map((cat) => {
          const pct = cat.total > 0 ? Math.round((cat.accountsSet / cat.total) * 100) : 0
          const allSet = cat.accountsNotSet === 0
          return (
            <div key={cat.category} className="space-y-1.5">
              <div className="flex items-center justify-between text-sm">
                <span className="font-medium">
                  {categoryLabels[cat.category] || cat.category}
                </span>
                <div className="flex items-center gap-2">
                  <span className="text-xs text-muted-foreground">
                    {cat.accountsSet} of {cat.total} activated
                  </span>
                  {allSet ? (
                    <CheckCircle2 className="h-3.5 w-3.5 text-emerald-500" />
                  ) : (
                    <Button
                      size="sm"
                      variant="ghost"
                      className="h-6 px-2 text-xs"
                      disabled={sendReminders.isPending}
                      onClick={() =>
                        handleSendReminder(`cat-${cat.category}`, {
                          category: cat.category as 'STARTUP' | 'BUSINESS_CONCEPT',
                        })
                      }
                    >
                      {sendingTarget === `cat-${cat.category}` ? (
                        <Loader2 className="mr-1 h-3 w-3 animate-spin" />
                      ) : (
                        <Send className="mr-1 h-3 w-3" />
                      )}
                      Remind
                    </Button>
                  )}
                </div>
              </div>
              <Progress value={pct} className="h-1.5" />
              {cat.accountsNotSet > 0 && (
                <p className="text-[11px] text-amber-600">
                  <AlertCircle className="mr-0.5 inline h-3 w-3" />
                  {cat.accountsNotSet} pending account setup
                </p>
              )}
            </div>
          )
        })}

        {/* Summary */}
        <div className="border-t pt-3">
          <div className="flex items-center justify-between text-sm">
            <span className="font-semibold">
              Total: {totalActivated} of {totalProjects} activated
            </span>
            {totalPending > 0 && (
              <Button
                size="sm"
                variant="outline"
                className="h-7 text-xs"
                disabled={sendReminders.isPending}
                onClick={() => handleSendReminder('all', {})}
              >
                {sendingTarget === 'all' ? (
                  <Loader2 className="mr-1.5 h-3 w-3 animate-spin" />
                ) : (
                  <Send className="mr-1.5 h-3 w-3" />
                )}
                Remind All ({totalPending})
              </Button>
            )}
          </div>
        </div>
        </>
        )}
      </CardContent>
    </Card>
  )
}
