'use client'

import { useState } from 'react'
import { useParams, useRouter } from 'next/navigation'
import { ArrowLeft, Loader2, PlayCircle, Zap } from 'lucide-react'
import { toast } from 'sonner'
import { trpc } from '@/lib/trpc/client'
import { Button } from '@/components/ui/button'
import { Card, CardContent, CardDescription, CardHeader, CardTitle } from '@/components/ui/card'
import {
  Select,
  SelectContent,
  SelectItem,
  SelectTrigger,
  SelectValue,
} from '@/components/ui/select'
import { Skeleton } from '@/components/ui/skeleton'
import { CoverageReport } from '@/components/admin/assignment/coverage-report'
import { AssignmentPreviewSheet } from '@/components/admin/assignment/assignment-preview-sheet'
import { Tabs, TabsContent, TabsList, TabsTrigger } from '@/components/ui/tabs'

export default function AssignmentsDashboardPage() {
  const params = useParams()
  const router = useRouter()
  const competitionId = params.competitionId as string

  const [selectedRoundId, setSelectedRoundId] = useState<string>('')
  const [previewSheetOpen, setPreviewSheetOpen] = useState(false)

  const aiAssignmentMutation = trpc.roundAssignment.aiPreview.useMutation({
    onSuccess: () => {
      toast.success('AI assignments ready!', {
        action: { label: 'Review', onClick: () => setPreviewSheetOpen(true) },
        duration: 10000,
      })
    },
    onError: (err) => toast.error(`AI generation failed: ${err.message}`),
  })

  const { data: competition, isLoading: isLoadingCompetition } = trpc.competition.getById.useQuery({
    id: competitionId,
  })

  const { data: selectedRound } = trpc.round.getById.useQuery(
    { id: selectedRoundId },
    { enabled: !!selectedRoundId }
  )

  const requiredReviews = (selectedRound?.configJson as Record<string, unknown>)?.requiredReviewsPerProject as number || 3

  const { data: unassignedQueue, isLoading: isLoadingQueue } =
    trpc.roundAssignment.unassignedQueue.useQuery(
      { roundId: selectedRoundId, requiredReviews },
      { enabled: !!selectedRoundId }
    )

  const rounds = competition?.rounds || []
  const currentRound = rounds.find((r) => r.id === selectedRoundId)

  if (isLoadingCompetition) {
    return (
    <div className="container mx-auto space-y-6 p-4 sm:p-6">
        <Skeleton className="h-10 w-full" />
        <Skeleton className="h-96 w-full" />
      </div>
    )
  }

  if (!competition) {
    return (
    <div className="container mx-auto space-y-6 p-4 sm:p-6">
        <p>Competition not found</p>
      </div>
    )
  }

  return (
    <div className="container mx-auto space-y-6 p-4 sm:p-6">
      <Button variant="ghost" onClick={() => router.back()} className="mb-4" aria-label="Back to competition details">
        <ArrowLeft className="mr-2 h-4 w-4" />
        Back to Competition
      </Button>

      <div className="flex flex-col sm:flex-row justify-between items-start sm:items-center gap-4">
        <div>
          <h1 className="text-3xl font-bold">Assignment Dashboard</h1>
          <p className="text-muted-foreground">Manage jury assignments for rounds</p>
        </div>
      </div>

      <Card>
        <CardHeader>
          <CardTitle>Select Round</CardTitle>
          <CardDescription>Choose a round to view and manage assignments</CardDescription>
        </CardHeader>
        <CardContent>
          <Select value={selectedRoundId} onValueChange={setSelectedRoundId}>
            <SelectTrigger className="w-full sm:w-[300px]">
              <SelectValue placeholder="Select a round..." />
            </SelectTrigger>
            <SelectContent>
              {rounds.length === 0 ? (
                <div className="px-2 py-1 text-sm text-muted-foreground">No rounds available</div>
              ) : (
                rounds.map((round) => (
                  <SelectItem key={round.id} value={round.id}>
                    {round.name} ({round.roundType})
                  </SelectItem>
                ))
              )}
            </SelectContent>
          </Select>
        </CardContent>
      </Card>

      {selectedRoundId && (
        <div className="space-y-6">
          <div className="flex justify-end gap-2">
            <Button
              onClick={() => {
                aiAssignmentMutation.mutate({ roundId: selectedRoundId, requiredReviews })
              }}
              disabled={aiAssignmentMutation.isPending}
            >
              {aiAssignmentMutation.isPending ? (
                <><Loader2 className="mr-2 h-4 w-4 animate-spin" />Generating...</>
              ) : (
                <><Zap className="mr-2 h-4 w-4" />{aiAssignmentMutation.data ? 'Regenerate' : 'Generate with AI'}</>
              )}
            </Button>
            {aiAssignmentMutation.data && (
              <Button variant="outline" onClick={() => setPreviewSheetOpen(true)}>
                Review Assignments
              </Button>
            )}
          </div>

          <Tabs defaultValue="coverage" className="w-full">
            <TabsList className="grid w-full grid-cols-2">
              <TabsTrigger value="coverage">Coverage Report</TabsTrigger>
              <TabsTrigger value="unassigned">Unassigned Queue</TabsTrigger>
            </TabsList>

            <TabsContent value="coverage" className="mt-6">
              <CoverageReport roundId={selectedRoundId} requiredReviews={requiredReviews} />
            </TabsContent>

            <TabsContent value="unassigned" className="mt-6">
              <Card>
                <CardHeader>
                  <CardTitle>Unassigned Projects</CardTitle>
                  <CardDescription>
                    Projects with fewer than {requiredReviews} assignments
                  </CardDescription>
                </CardHeader>
                <CardContent>
                  {isLoadingQueue ? (
                    <div className="space-y-2">
                      {[1, 2, 3].map((i) => (
                        <Skeleton key={i} className="h-16 w-full" />
                      ))}
                    </div>
                  ) : unassignedQueue && unassignedQueue.length > 0 ? (
                    <div className="space-y-2">
                      {unassignedQueue.map((project: any) => (
                        <div
                          key={project.id}
                          className="flex justify-between items-center p-3 border rounded-md"
                        >
                          <div>
                            <p className="font-medium">{project.title}</p>
                            <p className="text-sm text-muted-foreground">
                              {project.competitionCategory || 'No category'}
                            </p>
                          </div>
                          <div className="text-sm text-muted-foreground">
                            {project.assignmentCount || 0} / {requiredReviews} assignments
                          </div>
                        </div>
                      ))}
                    </div>
                  ) : (
                    <p className="text-sm text-muted-foreground">
                      All projects have sufficient assignments
                    </p>
                  )}
                </CardContent>
              </Card>
            </TabsContent>
          </Tabs>

          <AssignmentPreviewSheet
            roundId={selectedRoundId}
            open={previewSheetOpen}
            onOpenChange={setPreviewSheetOpen}
            requiredReviews={requiredReviews}
            aiResult={aiAssignmentMutation.data ?? null}
            isAIGenerating={aiAssignmentMutation.isPending}
            onGenerateAI={() => aiAssignmentMutation.mutate({ roundId: selectedRoundId, requiredReviews })}
            onResetAI={() => aiAssignmentMutation.reset()}
          />
        </div>
      )}
    </div>
  )
}