'use client';

import { useForm } from 'react-hook-form';
import { zodResolver } from '@hookform/resolvers/zod';
import * as z from 'zod';
import { Button } from '@/components/ui/button';
import {
  Form,
  FormControl,
  FormDescription,
  FormField,
  FormItem,
  FormLabel,
  FormMessage,
} from '@/components/ui/form';
import { Input } from '@/components/ui/input';
import { Textarea } from '@/components/ui/textarea';
import {
  Select,
  SelectContent,
  SelectItem,
  SelectTrigger,
  SelectValue,
} from '@/components/ui/select';
import { useCreateStory, useUpdateStory } from '@/lib/hooks/use-stories';
import { useEpics } from '@/lib/hooks/use-epics';
import type { Story, WorkItemPriority } from '@/types/project';
import { toast } from 'sonner';
import { Loader2 } from 'lucide-react';
import { useAuthStore } from '@/stores/authStore';

const storySchema = z.object({
  epicId: z.string().min(1, 'Parent Epic is required'),
  title: z
    .string()
    .min(1, 'Title is required')
    .max(200, 'Title must be less than 200 characters'),
  description: z
    .string()
    .max(2000, 'Description must be less than 2000 characters')
    .optional(),
  priority: z.enum(['Low', 'Medium', 'High', 'Critical']),
  estimatedHours: z
    .number()
    .min(0, 'Estimated hours must be positive')
    .optional()
    .or(z.literal('')),
});

type StoryFormValues = z.infer<typeof storySchema>;

interface StoryFormProps {
  story?: Story;
  epicId?: string;
  projectId?: string;
  onSuccess?: () => void;
  onCancel?: () => void;
}

export function StoryForm({
  story,
  epicId,
  projectId,
  onSuccess,
  onCancel,
}: StoryFormProps) {
  const isEditing = !!story;
  const user = useAuthStore((state) => state.user);
  const createStory = useCreateStory();
  const updateStory = useUpdateStory();

  // Fetch epics for parent epic selection
  const { data: epics = [], isLoading: epicsLoading } = useEpics(projectId);

  const form = useForm<StoryFormValues>({
    resolver: zodResolver(storySchema),
    defaultValues: {
      epicId: story?.epicId || epicId || '',
      title: story?.title || '',
      description: story?.description || '',
      priority: story?.priority || 'Medium',
      estimatedHours: story?.estimatedHours || ('' as any),
    },
  });

  async function onSubmit(data: StoryFormValues) {
    try {
      if (isEditing && story) {
        await updateStory.mutateAsync({
          id: story.id,
          data: {
            title: data.title,
            description: data.description,
            priority: data.priority,
            estimatedHours:
              typeof data.estimatedHours === 'number' ? data.estimatedHours : undefined,
          },
        });
        toast.success('Story updated successfully');
      } else {
        if (!user?.id) {
          toast.error('User not authenticated');
          return;
        }
        if (!projectId) {
          toast.error('Project ID is required');
          return;
        }
        await createStory.mutateAsync({
          epicId: data.epicId,
          projectId,
          title: data.title,
          description: data.description,
          priority: data.priority,
          estimatedHours:
            typeof data.estimatedHours === 'number' ? data.estimatedHours : undefined,
          createdBy: user.id,
        });
        toast.success('Story created successfully');
      }
      onSuccess?.();
    } catch (error) {
      const message = error instanceof Error ? error.message : 'Operation failed';
      toast.error(message);
    }
  }

  const isLoading = createStory.isPending || updateStory.isPending;

  return (
    <Form {...form}>
      <form onSubmit={form.handleSubmit(onSubmit)} className="space-y-6">
        <FormField
          control={form.control}
          name="epicId"
          render={({ field }) => (
            <FormItem>
              <FormLabel>Parent Epic *</FormLabel>
              <Select
                onValueChange={field.onChange}
                defaultValue={field.value}
                disabled={isEditing || !!epicId}
              >
                <FormControl>
                  <SelectTrigger>
                    <SelectValue placeholder="Select parent epic" />
                  </SelectTrigger>
                </FormControl>
                <SelectContent>
                  {epicsLoading ? (
                    <div className="p-2 text-sm text-muted-foreground">Loading epics...</div>
                  ) : epics.length === 0 ? (
                    <div className="p-2 text-sm text-muted-foreground">
                      No epics available
                    </div>
                  ) : (
                    epics.map((epic) => (
                      <SelectItem key={epic.id} value={epic.id}>
                        {epic.name}
                      </SelectItem>
                    ))
                  )}
                </SelectContent>
              </Select>
              <FormDescription>
                {isEditing ? 'Parent epic cannot be changed' : 'Select the parent epic'}
              </FormDescription>
              <FormMessage />
            </FormItem>
          )}
        />

        <FormField
          control={form.control}
          name="title"
          render={({ field }) => (
            <FormItem>
              <FormLabel>Story Title *</FormLabel>
              <FormControl>
                <Input placeholder="e.g., Login page with OAuth support" {...field} />
              </FormControl>
              <FormDescription>A clear, concise title for this story</FormDescription>
              <FormMessage />
            </FormItem>
          )}
        />

        <FormField
          control={form.control}
          name="description"
          render={({ field }) => (
            <FormItem>
              <FormLabel>Description</FormLabel>
              <FormControl>
                <Textarea
                  placeholder="Detailed description of the story..."
                  className="resize-none"
                  rows={6}
                  {...field}
                />
              </FormControl>
              <FormDescription>
                Optional detailed description (max 2000 characters)
              </FormDescription>
              <FormMessage />
            </FormItem>
          )}
        />

        <div className="grid grid-cols-2 gap-4">
          <FormField
            control={form.control}
            name="priority"
            render={({ field }) => (
              <FormItem>
                <FormLabel>Priority *</FormLabel>
                <Select onValueChange={field.onChange} defaultValue={field.value}>
                  <FormControl>
                    <SelectTrigger>
                      <SelectValue placeholder="Select priority" />
                    </SelectTrigger>
                  </FormControl>
                  <SelectContent>
                    <SelectItem value="Low">Low</SelectItem>
                    <SelectItem value="Medium">Medium</SelectItem>
                    <SelectItem value="High">High</SelectItem>
                    <SelectItem value="Critical">Critical</SelectItem>
                  </SelectContent>
                </Select>
                <FormMessage />
              </FormItem>
            )}
          />

          <FormField
            control={form.control}
            name="estimatedHours"
            render={({ field }) => (
              <FormItem>
                <FormLabel>Estimated Hours</FormLabel>
                <FormControl>
                  <Input
                    type="number"
                    placeholder="e.g., 8"
                    min="0"
                    step="0.5"
                    {...field}
                    onChange={(e) => {
                      const value = e.target.value;
                      field.onChange(value === '' ? '' : parseFloat(value));
                    }}
                    value={field.value === undefined ? '' : field.value}
                  />
                </FormControl>
                <FormDescription>Optional time estimate</FormDescription>
                <FormMessage />
              </FormItem>
            )}
          />
        </div>

        <div className="flex justify-end gap-3">
          {onCancel && (
            <Button
              type="button"
              variant="outline"
              onClick={onCancel}
              disabled={isLoading}
            >
              Cancel
            </Button>
          )}
          <Button type="submit" disabled={isLoading}>
            {isLoading && <Loader2 className="mr-2 h-4 w-4 animate-spin" />}
            {isEditing ? 'Update Story' : 'Create Story'}
          </Button>
        </div>
      </form>
    </Form>
  );
}