'use client'

import { useState, useCallback } from 'react'
import Link from 'next/link'
import type { Route } from 'next'
import { useRouter } from 'next/navigation'
import { trpc } from '@/lib/trpc/client'
import {
  Card,
  CardContent,
  CardHeader,
  CardTitle,
  CardDescription,
} from '@/components/ui/card'
import { Badge } from '@/components/ui/badge'
import { Button } from '@/components/ui/button'
import { Input } from '@/components/ui/input'
import { Skeleton } from '@/components/ui/skeleton'
import {
  Table,
  TableBody,
  TableCell,
  TableHead,
  TableHeader,
  TableRow,
} from '@/components/ui/table'
import {
  Select,
  SelectContent,
  SelectItem,
  SelectTrigger,
  SelectValue,
} from '@/components/ui/select'
import { StatusBadge } from '@/components/shared/status-badge'
import { CsvExportDialog } from '@/components/shared/csv-export-dialog'
import { scoreGradient } from '@/components/charts/chart-theme'
import {
  Search,
  ChevronLeft,
  ChevronRight,
  ArrowUpDown,
  ArrowUp,
  ArrowDown,
  ClipboardList,
  Download,
  X,
} from 'lucide-react'
import { cn } from '@/lib/utils'
import { useDebouncedCallback } from 'use-debounce'


export function ObserverProjectsContent() {
  const router = useRouter()
  const [search, setSearch] = useState('')
  const [debouncedSearch, setDebouncedSearch] = useState('')
  const [roundFilter, setRoundFilter] = useState('all')
  const [statusFilter, setStatusFilter] = useState('all')
  const [sortBy, setSortBy] = useState<'title' | 'score' | 'evaluations'>('title')
  const [sortDir, setSortDir] = useState<'asc' | 'desc'>('asc')
  const [page, setPage] = useState(1)
  const [perPage] = useState(20)
  const [csvOpen, setCsvOpen] = useState(false)
  const [csvExportData, setCsvExportData] = useState<
    { data: Record<string, unknown>[]; columns: string[] } | undefined
  >(undefined)
  const [csvLoading, setCsvLoading] = useState(false)

  const debouncedSetSearch = useDebouncedCallback((value: string) => {
    setDebouncedSearch(value)
    setPage(1)
  }, 300)

  const handleSearchChange = (value: string) => {
    setSearch(value)
    debouncedSetSearch(value)
  }

  const handleRoundChange = (value: string) => {
    setRoundFilter(value)
    setPage(1)
  }

  const handleStatusChange = (value: string) => {
    setStatusFilter(value)
    setPage(1)
  }

  const handleSort = (column: 'title' | 'score' | 'evaluations') => {
    if (sortBy === column) {
      setSortDir(sortDir === 'asc' ? 'desc' : 'asc')
    } else {
      setSortBy(column)
      setSortDir(column === 'title' ? 'asc' : 'desc')
    }
    setPage(1)
  }

  const clearFilters = () => {
    setSearch('')
    setDebouncedSearch('')
    setRoundFilter('all')
    setStatusFilter('all')
    setPage(1)
  }

  const activeFilterCount =
    (debouncedSearch ? 1 : 0) +
    (roundFilter !== 'all' ? 1 : 0) +
    (statusFilter !== 'all' ? 1 : 0)

  const { data: programs } = trpc.program.list.useQuery(
    { includeStages: true },
    { refetchInterval: 30_000 },
  )

  const rounds =
    programs?.flatMap((p) =>
      (p.rounds ?? []).map((r: { id: string; name: string; status: string; roundType?: string }) => ({
        id: r.id,
        name: r.name,
        programName: `${p.year} Edition`,
        status: r.status,
        roundType: r.roundType,
      })),
    ) ?? []

  const roundIdParam = roundFilter !== 'all' ? roundFilter : undefined

  const { data: projectsData, isLoading: projectsLoading } =
    trpc.analytics.getAllProjects.useQuery(
      {
        roundId: roundIdParam,
        search: debouncedSearch || undefined,
        status: statusFilter !== 'all' ? statusFilter : undefined,
        sortBy,
        sortDir,
        page,
        perPage,
      },
      { refetchInterval: 30_000 },
    )

  const handleRequestCsvData = useCallback(async () => {
    setCsvLoading(true)
    try {
      const allData = await new Promise<typeof projectsData>((resolve) => {
        resolve(projectsData)
      })

      if (!allData?.projects) {
        setCsvLoading(false)
        return undefined
      }

      const rows = allData.projects.map((p) => ({
        title: p.title,
        teamName: p.teamName ?? '',
        country: p.country ?? '',
        roundName: p.roundName ?? '',
        status: p.status,
        averageScore: p.averageScore !== null ? p.averageScore.toFixed(2) : '',
        evaluationCount: p.evaluationCount,
      }))

      const result = {
        data: rows,
        columns: ['title', 'teamName', 'country', 'roundName', 'status', 'averageScore', 'evaluationCount'],
      }
      setCsvExportData(result)
      setCsvLoading(false)
      return result
    } catch {
      setCsvLoading(false)
      return undefined
    }
  }, [projectsData])

  const SortIcon = ({ column }: { column: 'title' | 'score' | 'evaluations' }) => {
    if (sortBy !== column)
      return <ArrowUpDown className="ml-1 inline h-3 w-3 text-muted-foreground/50" />
    return sortDir === 'asc' ? (
      <ArrowUp className="ml-1 inline h-3 w-3" />
    ) : (
      <ArrowDown className="ml-1 inline h-3 w-3" />
    )
  }

  return (
    <div className="space-y-6">
      <div className="flex items-start justify-between gap-4">
        <div>
          <h1 className="text-2xl font-semibold tracking-tight">All Projects</h1>
          <p className="text-muted-foreground">
            {projectsData
              ? `${projectsData.total} project${projectsData.total !== 1 ? 's' : ''} total`
              : 'Loading projects...'}
          </p>
        </div>
        <Button variant="outline" size="sm" onClick={() => setCsvOpen(true)}>
          <Download className="mr-2 h-4 w-4" />
          Export CSV
        </Button>
      </div>

      <Card>
        <CardHeader className="pb-3">
          <CardTitle className="text-base">Filters</CardTitle>
          {activeFilterCount > 0 && (
            <CardDescription className="flex items-center gap-2">
              <Badge variant="secondary">{activeFilterCount} active</Badge>
              <button
                type="button"
                onClick={clearFilters}
                className="flex items-center gap-1 text-xs text-muted-foreground hover:text-foreground transition-colors"
              >
                <X className="h-3 w-3" />
                Clear all
              </button>
            </CardDescription>
          )}
        </CardHeader>
        <CardContent>
          <div className="flex flex-col gap-2 sm:flex-row sm:items-center sm:gap-3">
            <div className="relative flex-1">
              <Search className="absolute left-3 top-1/2 h-4 w-4 -translate-y-1/2 text-muted-foreground" />
              <Input
                placeholder="Search by title or team..."
                value={search}
                onChange={(e) => handleSearchChange(e.target.value)}
                className="pl-10"
              />
            </div>
            <Select value={roundFilter} onValueChange={handleRoundChange}>
              <SelectTrigger className="w-full sm:w-[220px]">
                <SelectValue placeholder="All Rounds" />
              </SelectTrigger>
              <SelectContent>
                <SelectItem value="all">All Rounds</SelectItem>
                {rounds.map((round) => (
                  <SelectItem key={round.id} value={round.id}>
                    {round.name}
                    {round.roundType ? ` (${round.roundType.replace(/_/g, ' ')})` : ''}
                  </SelectItem>
                ))}
              </SelectContent>
            </Select>
            <Select value={statusFilter} onValueChange={handleStatusChange}>
              <SelectTrigger className="w-full sm:w-[180px]">
                <SelectValue placeholder="All Statuses" />
              </SelectTrigger>
              <SelectContent>
                <SelectItem value="all">All Statuses</SelectItem>
                <SelectItem value="SUBMITTED">Submitted</SelectItem>
                <SelectItem value="ELIGIBLE">Eligible</SelectItem>
                <SelectItem value="ASSIGNED">Assigned</SelectItem>
                <SelectItem value="SEMIFINALIST">Semi-finalist</SelectItem>
                <SelectItem value="FINALIST">Finalist</SelectItem>
                <SelectItem value="REJECTED">Rejected</SelectItem>
              </SelectContent>
            </Select>
          </div>
        </CardContent>
      </Card>

      {projectsLoading ? (
        <Card>
          <CardContent className="pt-6 space-y-2">
            {[...Array(8)].map((_, i) => (
              <Skeleton key={i} className="h-12 w-full" />
            ))}
          </CardContent>
        </Card>
      ) : projectsData && projectsData.projects.length > 0 ? (
        <>
          <div className="hidden md:block">
            <Card>
              <CardContent className="p-0">
                <Table>
                  <TableHeader>
                    <TableRow>
                      <TableHead className="pl-6">
                        <button
                          type="button"
                          onClick={() => handleSort('title')}
                          className="inline-flex items-center hover:text-foreground transition-colors"
                        >
                          Project
                          <SortIcon column="title" />
                        </button>
                      </TableHead>
                      <TableHead>Country</TableHead>
                      <TableHead>Round</TableHead>
                      <TableHead>Status</TableHead>
                      <TableHead>
                        <button
                          type="button"
                          onClick={() => handleSort('score')}
                          className="inline-flex items-center hover:text-foreground transition-colors"
                        >
                          Score
                          <SortIcon column="score" />
                        </button>
                      </TableHead>
                      <TableHead>
                        <button
                          type="button"
                          onClick={() => handleSort('evaluations')}
                          className="inline-flex items-center hover:text-foreground transition-colors"
                        >
                          Jurors
                          <SortIcon column="evaluations" />
                        </button>
                      </TableHead>
                      <TableHead className="pr-6 w-10" />
                    </TableRow>
                  </TableHeader>
                  <TableBody>
                    {projectsData.projects.map((project) => (
                      <TableRow
                        key={project.id}
                        className="cursor-pointer hover:bg-muted/50"
                        onClick={() => router.push(`/observer/projects/${project.id}`)}
                      >
                        <TableCell className="pl-6 max-w-[260px]">
                          <Link
                            href={`/observer/projects/${project.id}` as Route}
                            className="font-medium hover:underline truncate block"
                            onClick={(e) => e.stopPropagation()}
                          >
                            {project.title}
                          </Link>
                          {project.teamName && (
                            <p className="text-xs text-muted-foreground truncate">
                              {project.teamName}
                            </p>
                          )}
                        </TableCell>
                        <TableCell className="text-sm">
                          {project.country ?? '-'}
                        </TableCell>
                        <TableCell>
                          <Badge variant="outline" className="text-xs whitespace-nowrap">
                            {project.roundName}
                          </Badge>
                        </TableCell>
                        <TableCell>
                          <StatusBadge status={project.status} />
                        </TableCell>
                        <TableCell>
                          {project.averageScore !== null ? (
                            <div className="flex items-center gap-2">
                              <span className="tabular-nums w-8 text-sm">
                                {project.averageScore.toFixed(1)}
                              </span>
                              <div className="h-2 w-16 rounded-full bg-muted overflow-hidden">
                                <div
                                  className="h-full rounded-full"
                                  style={{
                                    width: `${(project.averageScore / 10) * 100}%`,
                                    backgroundColor: scoreGradient(project.averageScore),
                                  }}
                                />
                              </div>
                            </div>
                          ) : (
                            <span className="text-muted-foreground text-sm">-</span>
                          )}
                        </TableCell>
                        <TableCell className="tabular-nums text-sm">
                          {project.evaluationCount}
                        </TableCell>
                        <TableCell className="pr-6">
                          <Link
                            href={`/observer/projects/${project.id}` as Route}
                            onClick={(e) => e.stopPropagation()}
                          >
                            <ChevronRight className="h-4 w-4 text-muted-foreground" />
                          </Link>
                        </TableCell>
                      </TableRow>
                    ))}
                  </TableBody>
                </Table>
              </CardContent>
            </Card>
          </div>

          <div className="space-y-3 md:hidden">
            {projectsData.projects.map((project) => (
              <Link
                key={project.id}
                href={`/observer/projects/${project.id}` as Route}
              >
                <Card className="transition-colors hover:bg-muted/50">
                  <CardContent className="pt-4 space-y-2">
                    <div className="flex items-start justify-between gap-2">
                      <div className="min-w-0">
                        <p className="font-medium text-sm leading-tight truncate">
                          {project.title}
                        </p>
                        {project.teamName && (
                          <p className="text-xs text-muted-foreground truncate">
                            {project.teamName}
                          </p>
                        )}
                      </div>
                      <StatusBadge status={project.status} />
                    </div>
                    <div className="flex items-center justify-between gap-2 text-xs text-muted-foreground">
                      <Badge variant="outline" className="text-xs">
                        {project.roundName}
                      </Badge>
                      <div className="flex gap-3">
                        <span>
                          Score:{' '}
                          {project.averageScore !== null
                            ? project.averageScore.toFixed(1)
                            : '-'}
                        </span>
                        <span>
                          {project.evaluationCount} eval
                          {project.evaluationCount !== 1 ? 's' : ''}
                        </span>
                      </div>
                    </div>
                  </CardContent>
                </Card>
              </Link>
            ))}
          </div>

          <div className="flex items-center justify-between">
            <p className="text-sm text-muted-foreground">
              Page {projectsData.page} of {projectsData.totalPages} &middot;{' '}
              {projectsData.total} result{projectsData.total !== 1 ? 's' : ''}
            </p>
            <div className="flex items-center gap-2">
              <Button
                variant="outline"
                size="sm"
                onClick={() => setPage((p) => Math.max(1, p - 1))}
                disabled={page <= 1}
              >
                <ChevronLeft className="h-4 w-4" />
              </Button>
              <Button
                variant="outline"
                size="sm"
                onClick={() =>
                  setPage((p) => Math.min(projectsData.totalPages, p + 1))
                }
                disabled={page >= projectsData.totalPages}
              >
                <ChevronRight className="h-4 w-4" />
              </Button>
            </div>
          </div>
        </>
      ) : (
        <div
          className={cn(
            'flex flex-col items-center justify-center rounded-lg border border-dashed py-16 text-center',
          )}
        >
          <ClipboardList className="h-12 w-12 text-muted-foreground/50" />
          <p className="mt-3 font-medium">
            {activeFilterCount > 0 ? 'No projects match your filters' : 'No projects found'}
          </p>
          {activeFilterCount > 0 && (
            <Button variant="ghost" size="sm" className="mt-2" onClick={clearFilters}>
              Clear filters
            </Button>
          )}
        </div>
      )}

      <CsvExportDialog
        open={csvOpen}
        onOpenChange={setCsvOpen}
        exportData={csvExportData}
        isLoading={csvLoading}
        filename="observer-projects"
        onRequestData={handleRequestCsvData}
      />
    </div>
  )
}