'use client'

import { useState } from 'react'
import { trpc } from '@/lib/trpc/client'
import { toast } from 'sonner'
import { Button } from '@/components/ui/button'
import { Card, CardContent, CardDescription, CardHeader, CardTitle } from '@/components/ui/card'
import { Badge } from '@/components/ui/badge'
import { Input } from '@/components/ui/input'
import { Textarea } from '@/components/ui/textarea'
import { Checkbox } from '@/components/ui/checkbox'
import { Skeleton } from '@/components/ui/skeleton'
import {
  Dialog,
  DialogContent,
  DialogDescription,
  DialogFooter,
  DialogHeader,
  DialogTitle,
} from '@/components/ui/dialog'
import {
  AlertDialog,
  AlertDialogAction,
  AlertDialogCancel,
  AlertDialogContent,
  AlertDialogDescription,
  AlertDialogFooter,
  AlertDialogHeader,
  AlertDialogTitle,
  AlertDialogTrigger,
} from '@/components/ui/alert-dialog'
import {
  Loader2,
  Plus,
  Pencil,
  Trash2,
  FileText,
  GripVertical,
  FileCheck,
  FileQuestion,
} from 'lucide-react'

type FileRequirementsEditorProps = {
  roundId: string
  windowOpenAt?: Date | string | null
  windowCloseAt?: Date | string | null
}

type FormState = {
  name: string
  description: string
  acceptedMimeTypes: string[]
  maxSizeMB: string
  isRequired: boolean
}

const emptyForm: FormState = {
  name: '',
  description: '',
  acceptedMimeTypes: [],
  maxSizeMB: '',
  isRequired: true,
}

const MIME_TYPE_OPTIONS: { label: string; value: string }[] = [
  { label: 'PDF', value: 'application/pdf' },
  { label: 'Images', value: 'image/*' },
  { label: 'Video', value: 'video/*' },
  { label: 'Word', value: 'application/vnd.openxmlformats-officedocument.wordprocessingml.document' },
  { label: 'Excel', value: 'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet' },
  { label: 'PowerPoint', value: 'application/vnd.openxmlformats-officedocument.presentationml.presentation' },
]

function getMimeLabel(mime: string): string {
  const preset = MIME_TYPE_OPTIONS.find((p) => p.value === mime)
  if (preset) return preset.label
  if (mime.endsWith('/*')) return mime.replace('/*', '')
  return mime
}

export function FileRequirementsEditor({ roundId, windowOpenAt, windowCloseAt }: FileRequirementsEditorProps) {
  const [dialogOpen, setDialogOpen] = useState(false)
  const [editingId, setEditingId] = useState<string | null>(null)
  const [form, setForm] = useState<FormState>(emptyForm)

  const utils = trpc.useUtils()

  const { data: requirements, isLoading } = trpc.file.listRequirements.useQuery({ roundId })

  const createMutation = trpc.file.createRequirement.useMutation({
    onSuccess: () => {
      utils.file.listRequirements.invalidate({ roundId })
      toast.success('Requirement added')
      closeDialog()
    },
    onError: (err) => toast.error(err.message),
  })

  const updateMutation = trpc.file.updateRequirement.useMutation({
    onSuccess: () => {
      utils.file.listRequirements.invalidate({ roundId })
      toast.success('Requirement updated')
      closeDialog()
    },
    onError: (err) => toast.error(err.message),
  })

  const deleteMutation = trpc.file.deleteRequirement.useMutation({
    onSuccess: () => {
      utils.file.listRequirements.invalidate({ roundId })
      toast.success('Requirement removed')
    },
    onError: (err) => toast.error(err.message),
  })

  const closeDialog = () => {
    setDialogOpen(false)
    setEditingId(null)
    setForm(emptyForm)
  }

  const openCreateDialog = () => {
    setForm(emptyForm)
    setEditingId(null)
    setDialogOpen(true)
  }

  const openEditDialog = (req: any) => {
    setForm({
      name: req.name,
      description: req.description || '',
      acceptedMimeTypes: req.acceptedMimeTypes || [],
      maxSizeMB: req.maxSizeMB?.toString() || '',
      isRequired: req.isRequired ?? true,
    })
    setEditingId(req.id)
    setDialogOpen(true)
  }

  const toggleMimeType = (mime: string) => {
    setForm((prev) => ({
      ...prev,
      acceptedMimeTypes: prev.acceptedMimeTypes.includes(mime)
        ? prev.acceptedMimeTypes.filter((m) => m !== mime)
        : [...prev.acceptedMimeTypes, mime],
    }))
  }

  const handleSubmit = () => {
    const maxSize = form.maxSizeMB ? parseInt(form.maxSizeMB, 10) : undefined

    if (editingId) {
      updateMutation.mutate({
        id: editingId,
        name: form.name,
        description: form.description || null,
        acceptedMimeTypes: form.acceptedMimeTypes,
        maxSizeMB: maxSize ?? null,
        isRequired: form.isRequired,
      })
    } else {
      createMutation.mutate({
        roundId,
        name: form.name,
        description: form.description || undefined,
        acceptedMimeTypes: form.acceptedMimeTypes,
        maxSizeMB: maxSize,
        isRequired: form.isRequired,
        sortOrder: (requirements?.length ?? 0),
      })
    }
  }

  const isSaving = createMutation.isPending || updateMutation.isPending

  if (isLoading) {
    return (
      <div className="space-y-3">
        <Skeleton className="h-10 w-full" />
        {[1, 2, 3].map((i) => <Skeleton key={i} className="h-20 w-full" />)}
      </div>
    )
  }

  return (
    <div className="space-y-4">
      {/* Submission period info */}
      <Card>
        <CardContent className="pt-4 pb-3">
          <div className="flex items-center justify-between">
            <div>
              <p className="text-sm font-medium">Submission Period</p>
              <p className="text-xs text-muted-foreground mt-0.5">
                Applicants can upload documents during the round&apos;s active window
              </p>
            </div>
            <div className="text-right text-sm">
              {windowOpenAt || windowCloseAt ? (
                <>
                  <p className="font-medium">
                    {windowOpenAt ? new Date(windowOpenAt).toLocaleDateString() : 'No start'} &mdash;{' '}
                    {windowCloseAt ? new Date(windowCloseAt).toLocaleDateString() : 'No deadline'}
                  </p>
                  <p className="text-xs text-muted-foreground">
                    Set in the Config tab under round time windows
                  </p>
                </>
              ) : (
                <p className="text-muted-foreground">No dates configured &mdash; set in Config tab</p>
              )}
            </div>
          </div>
        </CardContent>
      </Card>

      {/* Requirements list */}
      <Card>
        <CardHeader>
          <div className="flex items-center justify-between">
            <div>
              <CardTitle className="text-base">Required Documents</CardTitle>
              <CardDescription>
                Define what files applicants must submit for this round
              </CardDescription>
            </div>
            <Button size="sm" onClick={openCreateDialog}>
              <Plus className="h-4 w-4 mr-1.5" />
              Add Requirement
            </Button>
          </div>
        </CardHeader>
        <CardContent>
          {!requirements || requirements.length === 0 ? (
            <div className="flex flex-col items-center justify-center py-10 text-center">
              <div className="rounded-full bg-muted p-4 mb-4">
                <FileText className="h-8 w-8 text-muted-foreground" />
              </div>
              <p className="text-sm font-medium">No Document Requirements</p>
              <p className="text-xs text-muted-foreground mt-1 max-w-sm">
                Add requirements to specify what documents applicants must upload during this round.
              </p>
              <Button size="sm" variant="outline" className="mt-4" onClick={openCreateDialog}>
                <Plus className="h-4 w-4 mr-1.5" />
                Add First Requirement
              </Button>
            </div>
          ) : (
            <div className="space-y-2">
              {requirements.map((req: any) => (
                <div
                  key={req.id}
                  className="flex items-start gap-3 p-3 rounded-lg border hover:bg-muted/30 transition-colors"
                >
                  <div className="mt-0.5 text-muted-foreground">
                    {req.isRequired ? (
                      <FileCheck className="h-4 w-4 text-blue-500" />
                    ) : (
                      <FileQuestion className="h-4 w-4 text-gray-400" />
                    )}
                  </div>
                  <div className="flex-1 min-w-0">
                    <div className="flex items-center gap-2">
                      <p className="text-sm font-medium">{req.name}</p>
                      <Badge variant={req.isRequired ? 'default' : 'secondary'} className="text-[10px]">
                        {req.isRequired ? 'Required' : 'Optional'}
                      </Badge>
                    </div>
                    {req.description && (
                      <p className="text-xs text-muted-foreground mt-0.5">{req.description}</p>
                    )}
                    <div className="flex flex-wrap gap-1 mt-1.5">
                      {req.acceptedMimeTypes?.length > 0 ? (
                        req.acceptedMimeTypes.map((t: string) => (
                          <Badge key={t} variant="outline" className="text-[10px]">
                            {getMimeLabel(t)}
                          </Badge>
                        ))
                      ) : (
                        <Badge variant="outline" className="text-[10px]">
                          Any file type
                        </Badge>
                      )}
                      {req.maxSizeMB && (
                        <Badge variant="outline" className="text-[10px]">
                          Max {req.maxSizeMB} MB
                        </Badge>
                      )}
                    </div>
                  </div>
                  <div className="flex items-center gap-1 shrink-0">
                    <Button variant="ghost" size="icon" className="h-7 w-7" onClick={() => openEditDialog(req)}>
                      <Pencil className="h-3.5 w-3.5" />
                    </Button>
                    <AlertDialog>
                      <AlertDialogTrigger asChild>
                        <Button variant="ghost" size="icon" className="h-7 w-7 text-destructive hover:text-destructive">
                          <Trash2 className="h-3.5 w-3.5" />
                        </Button>
                      </AlertDialogTrigger>
                      <AlertDialogContent>
                        <AlertDialogHeader>
                          <AlertDialogTitle>Delete requirement?</AlertDialogTitle>
                          <AlertDialogDescription>
                            This will remove &quot;{req.name}&quot; from the round. Previously uploaded files will not be deleted.
                          </AlertDialogDescription>
                        </AlertDialogHeader>
                        <AlertDialogFooter>
                          <AlertDialogCancel>Cancel</AlertDialogCancel>
                          <AlertDialogAction
                            onClick={() => deleteMutation.mutate({ id: req.id })}
                            className="bg-destructive text-destructive-foreground hover:bg-destructive/90"
                          >
                            Delete
                          </AlertDialogAction>
                        </AlertDialogFooter>
                      </AlertDialogContent>
                    </AlertDialog>
                  </div>
                </div>
              ))}
            </div>
          )}
        </CardContent>
      </Card>

      {/* Create / Edit Dialog */}
      <Dialog open={dialogOpen} onOpenChange={(open) => { if (!open) closeDialog() }}>
        <DialogContent>
          <DialogHeader>
            <DialogTitle>{editingId ? 'Edit Requirement' : 'Add Document Requirement'}</DialogTitle>
            <DialogDescription>
              {editingId
                ? 'Update the document requirement details.'
                : 'Define a new document that applicants must submit.'}
            </DialogDescription>
          </DialogHeader>
          <div className="space-y-4">
            <div className="space-y-2">
              <label className="text-sm font-medium">Name</label>
              <Input
                placeholder="e.g. Business Plan, Pitch Deck, Financial Projections"
                value={form.name}
                onChange={(e) => setForm((f) => ({ ...f, name: e.target.value }))}
              />
            </div>
            <div className="space-y-2">
              <label className="text-sm font-medium">Description</label>
              <Textarea
                placeholder="Describe what this document should contain..."
                rows={3}
                value={form.description}
                onChange={(e) => setForm((f) => ({ ...f, description: e.target.value }))}
              />
            </div>
            <div className="space-y-2">
              <label className="text-sm font-medium">Accepted File Types</label>
              <div className="flex flex-wrap gap-2">
                {MIME_TYPE_OPTIONS.map((opt) => (
                  <Badge
                    key={opt.value}
                    variant={form.acceptedMimeTypes.includes(opt.value) ? 'default' : 'outline'}
                    className="cursor-pointer select-none"
                    onClick={() => toggleMimeType(opt.value)}
                  >
                    {opt.label}
                  </Badge>
                ))}
              </div>
              <p className="text-xs text-muted-foreground">
                Select one or more file types. Leave empty to accept any file type.
              </p>
            </div>
            <div className="space-y-2">
              <label className="text-sm font-medium">Max File Size (MB)</label>
              <Input
                type="number"
                placeholder="e.g. 50"
                value={form.maxSizeMB}
                onChange={(e) => setForm((f) => ({ ...f, maxSizeMB: e.target.value }))}
              />
            </div>
            <div className="flex items-center gap-2">
              <Checkbox
                id="isRequired"
                checked={form.isRequired}
                onCheckedChange={(checked) => setForm((f) => ({ ...f, isRequired: !!checked }))}
              />
              <label htmlFor="isRequired" className="text-sm">
                Required document (applicant must upload to proceed)
              </label>
            </div>
          </div>
          <DialogFooter>
            <Button variant="outline" onClick={closeDialog}>Cancel</Button>
            <Button onClick={handleSubmit} disabled={isSaving || !form.name.trim()}>
              {isSaving && <Loader2 className="h-4 w-4 mr-2 animate-spin" />}
              {editingId ? 'Update' : 'Add Requirement'}
            </Button>
          </DialogFooter>
        </DialogContent>
      </Dialog>
    </div>
  )
}