'use client'

import { useState, useTransition, useEffect, useRef } from 'react'
import { useRouter } from 'next/navigation'
import { Button } from "@/components/ui/button"
import {
  Dialog,
  DialogContent,
  DialogDescription,
  DialogFooter,
  DialogHeader,
  DialogTitle,
} from "@/components/ui/dialog"
import { Input } from "@/components/ui/input"
import { Label } from "@/components/ui/label"
import { Avatar, AvatarFallback, AvatarImage } from "@/components/ui/avatar"
import { Badge } from "@/components/ui/badge"
import { X, Loader2, Mail } from "lucide-react"
import { addCollaborator, removeCollaborator, getNoteCollaborators } from "@/app/actions/notes"
import { toast } from "sonner"

interface Collaborator {
  id: string
  name: string | null
  email: string
  image: string | null
}

interface CollaboratorDialogProps {
  open: boolean
  onOpenChange: (open: boolean) => void
  noteId: string
  noteOwnerId: string
  currentUserId: string
  onCollaboratorsChange?: (collaboratorIds: string[]) => void
  initialCollaborators?: string[]
}

export function CollaboratorDialog({
  open,
  onOpenChange,
  noteId,
  noteOwnerId,
  currentUserId,
  onCollaboratorsChange,
  initialCollaborators = []
}: CollaboratorDialogProps) {
  const router = useRouter()
  const [collaborators, setCollaborators] = useState<Collaborator[]>([])
  const [localCollaboratorIds, setLocalCollaboratorIds] = useState<string[]>(initialCollaborators)
  const [email, setEmail] = useState('')
  const [isLoading, setIsLoading] = useState(false)
  const [isPending, startTransition] = useTransition()
  const [justAddedCollaborator, setJustAddedCollaborator] = useState(false)
  const isOwner = currentUserId === noteOwnerId
  const isCreationMode = !noteId
  const hasLoadedRef = useRef(false)

  // Load collaborators when dialog opens (only for existing notes)
  const loadCollaborators = async () => {
    if (isCreationMode) return

    setIsLoading(true)
    try {
      const result = await getNoteCollaborators(noteId)
      setCollaborators(result)
      hasLoadedRef.current = true
    } catch (error: any) {
      toast.error(error.message || 'Error loading collaborators')
    } finally {
      setIsLoading(false)
    }
  }

  // Load collaborators when dialog opens
  useEffect(() => {
    if (open && !isCreationMode && !hasLoadedRef.current && !isLoading) {
      loadCollaborators()
    }
    // Reset when dialog closes
    if (!open) {
      hasLoadedRef.current = false
    }
  }, [open, isCreationMode])

  // Sync initial collaborators when prop changes (creation mode)
  useEffect(() => {
    if (isCreationMode) {
      setLocalCollaboratorIds(initialCollaborators)
    }
  }, [initialCollaborators, isCreationMode])

  // Handle adding a collaborator
  const handleAddCollaborator = async (e: React.FormEvent) => {
    e.preventDefault()

    if (!email.trim()) return

    if (isCreationMode) {
      // Creation mode: just add email as placeholder, will be resolved on note creation
      if (!localCollaboratorIds.includes(email)) {
        const newIds = [...localCollaboratorIds, email]
        setLocalCollaboratorIds(newIds)
        onCollaboratorsChange?.(newIds)
        setEmail('')
        toast.success(`${email} will be added as collaborator when note is created`)
      } else {
        toast.warning('This email is already in the list')
      }
    } else {
      // Existing note mode: use server action
      setJustAddedCollaborator(true)
      startTransition(async () => {
        try {
          const result = await addCollaborator(noteId, email)

          if (result.success) {
            setCollaborators([...collaborators, result.user])
            setEmail('')
            toast.success(`${result.user.name || result.user.email} now has access to this note`)
            // Don't refresh here - it would close the dialog!
            // The collaborator list is already updated in local state
            setJustAddedCollaborator(false)
          }
        } catch (error: any) {
          toast.error(error.message || 'Failed to add collaborator')
          setJustAddedCollaborator(false)
        }
      })
    }
  }

  // Handle removing a collaborator
  const handleRemoveCollaborator = async (userId: string) => {
    if (isCreationMode) {
      // Creation mode: remove from local list
      const newIds = localCollaboratorIds.filter(id => id !== userId)
      setLocalCollaboratorIds(newIds)
      onCollaboratorsChange?.(newIds)
    } else {
      // Existing note mode: use server action
      startTransition(async () => {
        try {
          await removeCollaborator(noteId, userId)
          setCollaborators(collaborators.filter(c => c.id !== userId))
          toast.success('Access has been revoked')
          // Don't refresh here - it would close the dialog!
          // The collaborator list is already updated in local state
        } catch (error: any) {
          toast.error(error.message || 'Failed to remove collaborator')
        }
      })
    }
  }

  return (
    <Dialog open={open} onOpenChange={onOpenChange}>
      <DialogContent
        className="sm:max-w-md"
        onInteractOutside={(event) => {
          // Prevent dialog from closing when interacting with Sonner toasts
          // Sonner uses data-sonner-toast NOT data-toast
          const target = event.target as HTMLElement;

          const isSonnerElement =
            target.closest('[data-sonner-toast]') ||
            target.closest('[data-sonner-toaster]') ||
            target.closest('[data-icon]') ||
            target.closest('[data-content]') ||
            target.closest('[data-description]') ||
            target.closest('[data-title]') ||
            target.closest('[data-button]');

          if (isSonnerElement) {
            event.preventDefault();
            return;
          }

          // Also prevent if target is the toast container itself
          if (target.getAttribute('data-sonner-toaster') !== null) {
            event.preventDefault();
            return;
          }
        }}
      >
        <DialogHeader>
          <DialogTitle>Share with collaborators</DialogTitle>
          <DialogDescription>
            {isOwner
              ? "Add people to collaborate on this note by their email address."
              : "You have access to this note. Only the owner can manage collaborators."}
          </DialogDescription>
        </DialogHeader>

        <div className="space-y-4 py-4">
          {isOwner && (
            <form onSubmit={handleAddCollaborator} className="flex gap-2">
              <div className="flex-1">
                <Label htmlFor="email" className="sr-only">Email address</Label>
                <Input
                  id="email"
                  type="email"
                  placeholder="Enter email address"
                  value={email}
                  onChange={(e) => setEmail(e.target.value)}
                  disabled={isPending}
                />
              </div>
              <Button type="submit" disabled={isPending || !email.trim()}>
                {isPending ? (
                  <Loader2 className="h-4 w-4 animate-spin" />
                ) : (
                  <>
                    <Mail className="h-4 w-4 mr-2" />
                    Invite
                  </>
                )}
              </Button>
            </form>
          )}

          <div className="space-y-2">
            <Label>People with access</Label>
            {isLoading ? (
              <div className="flex justify-center py-4">
                <Loader2 className="h-6 w-6 animate-spin text-muted-foreground" />
              </div>
            ) : isCreationMode ? (
              // Creation mode: show emails
              localCollaboratorIds.length === 0 ? (
                <p className="text-sm text-muted-foreground text-center py-4">
                  No collaborators yet. Add someone above!
                </p>
              ) : (
                <div className="space-y-2">
                  {localCollaboratorIds.map((emailOrId, idx) => (
                    <div
                      key={idx}
                      data-testid="collaborator-item"
                      className="flex items-center justify-between p-2 rounded-lg border bg-muted/50"
                    >
                      <div className="flex items-center gap-3 flex-1">
                        <Avatar className="h-8 w-8">
                          <AvatarFallback>
                            {emailOrId.charAt(0).toUpperCase()}
                          </AvatarFallback>
                        </Avatar>
                        <div className="flex-1 min-w-0">
                          <p className="text-sm font-medium truncate">
                            Pending Invite
                          </p>
                          <p className="text-xs text-muted-foreground truncate">
                            {emailOrId}
                          </p>
                        </div>
                        <Badge variant="outline" className="ml-2">Pending</Badge>
                      </div>
                      <Button
                        variant="ghost"
                        size="sm"
                        className="h-8 w-8 p-0"
                        onClick={() => handleRemoveCollaborator(emailOrId)}
                        disabled={isPending}
                        aria-label="Remove"
                      >
                        <X className="h-4 w-4" />
                      </Button>
                    </div>
                  ))}
                </div>
              )
            ) : collaborators.length === 0 ? (
              <p className="text-sm text-muted-foreground text-center py-4">
                No collaborators yet. {isOwner && "Add someone above!"}
              </p>
            ) : (
              <div className="space-y-2">
                {collaborators.map((collaborator) => (
                  <div
                    key={collaborator.id}
                    data-testid="collaborator-item"
                    className="flex items-center justify-between p-2 rounded-lg border bg-muted/50"
                  >
                    <div className="flex items-center gap-3 flex-1">
                      <Avatar className="h-8 w-8">
                        <AvatarImage src={collaborator.image || undefined} />
                        <AvatarFallback>
                          {collaborator.name?.charAt(0).toUpperCase() || collaborator.email.charAt(0).toUpperCase()}
                        </AvatarFallback>
                      </Avatar>
                      <div className="flex-1 min-w-0">
                        <p className="text-sm font-medium truncate">
                          {collaborator.name || 'Unnamed User'}
                        </p>
                        <p className="text-xs text-muted-foreground truncate">
                          {collaborator.email}
                        </p>
                      </div>
                      {collaborator.id === noteOwnerId && (
                        <Badge variant="secondary" className="ml-2">Owner</Badge>
                      )}
                    </div>
                    {isOwner && collaborator.id !== noteOwnerId && (
                      <Button
                        variant="ghost"
                        size="sm"
                        className="h-8 w-8 p-0"
                        onClick={() => handleRemoveCollaborator(collaborator.id)}
                        disabled={isPending}
                        aria-label="Remove"
                      >
                        <X className="h-4 w-4" />
                      </Button>
                    )}
                  </div>
                ))}
              </div>
            )}
          </div>
        </div>

        <DialogFooter>
          <Button variant="outline" onClick={() => onOpenChange(false)}>
            Done
          </Button>
        </DialogFooter>
      </DialogContent>
    </Dialog>
  )
}