'use client';

import React, { useEffect, useState } from 'react';
import { useRouter } from 'next/navigation';
import { toast } from 'sonner';
import Image from 'next/image';
import { SidebarProvider, SidebarInset } from '@/components/ui/sidebar';
import { AppSidebar } from '@/components/app-sidebar';
import { SiteHeader } from '@/components/site-header';
import {
  Card,
  CardContent,
  CardHeader,
  CardTitle,
} from '@/components/ui/card';
import {
  Field,
  FieldGroup,
  FieldLabel,
  FieldDescription,
} from '@/components/ui/field';
import { Input } from '@/components/ui/input';
import { Button } from '@/components/ui/button';
import { Textarea } from '@/components/ui/textarea';

interface VideoData {
  id: string;
  title: string;
  description: string;
  thumbnail?: string;
  playlistTitle: string;
  courseTitle: string;
  restrictedCourseIds?: string[];
}

interface CourseData {
  id: string;
  title: string;
}

export default function EditVideoClient({ video }: { video: VideoData }) {
  const router = useRouter();
  const [title, setTitle] = useState(video.title);
  const [description, setDescription] = useState(video.description);
  const [thumbFile, setThumbFile] = useState<File | null>(null);
  const [thumbPreview, setThumbPreview] = useState(video.thumbnail);
  const [loading, setLoading] = useState(false);
  const [courses, setCourses] = useState<CourseData[]>([]);
  const [coursesLoading, setCoursesLoading] = useState(true);
  const [restrictedCourseIds, setRestrictedCourseIds] = useState<string[]>(
    video.restrictedCourseIds ?? []
  );

  useEffect(() => {
    let cancelled = false;
    setCoursesLoading(true);
    fetch('/api/admin/meta')
      .then(async (res) => {
        if (!res.ok) throw new Error(`HTTP ${res.status}`);
        const json = await res.json();
        if (!cancelled) {
          setCourses(json.courses ?? []);
        }
      })
      .catch((err) => {
        console.error('Failed to load courses', err);
        if (!cancelled) {
          setCourses([]);
        }
      })
      .finally(() => {
        if (!cancelled) setCoursesLoading(false);
      });
    return () => {
      cancelled = true;
    };
  }, []);

  const handleThumbnailChange = (e: React.ChangeEvent<HTMLInputElement>) => {
    const file = e.target.files?.[0];
    if (file) {
      setThumbFile(file);
      const reader = new FileReader();
      reader.onload = (event) => {
        setThumbPreview(event.target?.result as string);
      };
      reader.readAsDataURL(file);
    }
  };

  const handleSubmit = async (e: React.FormEvent) => {
    e.preventDefault();
    setLoading(true);

    try {
      const formData = new FormData();
      formData.append('videoId', video.id);
      formData.append('title', title);
      formData.append('description', description);
      if (thumbFile) {
        formData.append('thumbnail', thumbFile);
      }
      formData.append('restrictedCourseIds', JSON.stringify(restrictedCourseIds));

      const res = await fetch('/api/admin/update-video', {
        method: 'POST',
        body: formData,
      });

      if (res.ok) {
        toast.success('Video updated successfully');
        router.push('/admin/videos');
      } else {
        const err = await res.text();
        toast.error('Failed to update video: ' + err);
      }
    } catch (err: any) {
      toast.error('Error: ' + String(err.message ?? err));
    } finally {
      setLoading(false);
    }
  };

  return (
    <SidebarProvider
      style={
        {
          '--sidebar-width': 'calc(var(--spacing) * 72)',
          '--header-height': 'calc(var(--spacing) * 12)',
        } as React.CSSProperties
      }
    >
      <AppSidebar variant="inset" />
      <SidebarInset>
        <SiteHeader />
        <div className="flex flex-1 flex-col">
          <div className="@container/main flex flex-1 flex-col gap-2">
            <div className="flex flex-col gap-6 py-4 md:gap-6 md:py-6 px-4 lg:px-16">
              <div>
                <h1 className="text-3xl font-bold tracking-tight mb-2">
                  Edit Video
                </h1>
                <p className="text-muted-foreground">
                  {video.courseTitle} • {video.playlistTitle}
                </p>
              </div>

              <Card>
                <CardHeader>
                  <CardTitle>{video.title}</CardTitle>
                </CardHeader>
                <CardContent>
                  <form onSubmit={handleSubmit}>
                    <FieldGroup>
                      <Field>
                        <FieldLabel htmlFor="title">Video Title</FieldLabel>
                        <Input
                          id="title"
                          required
                          value={title}
                          onChange={(e) => setTitle(e.target.value)}
                          placeholder="Enter video title"
                        />
                      </Field>

                      <Field>
                        <FieldLabel htmlFor="description">
                          Description
                        </FieldLabel>
                        <FieldDescription>
                          Optional description for the video
                        </FieldDescription>
                        <Textarea
                          id="description"
                          value={description}
                          onChange={(e) => setDescription(e.target.value)}
                          placeholder="Enter video description"
                          rows={4}
                        />
                      </Field>

                      <Field>
                        <FieldLabel>Restricted courses</FieldLabel>
                        <FieldDescription>
                          Only users enrolled in the checked courses will see this video. Leave
                          empty to allow all enrolled courses to access it.
                        </FieldDescription>
                        {coursesLoading ? (
                          <div className="text-sm text-muted-foreground">Loading courses…</div>
                        ) : courses.length === 0 ? (
                          <div className="text-sm text-muted-foreground">No courses available.</div>
                        ) : (
                          <div className="grid gap-2 text-sm">
                            {courses.map((course) => (
                              <label
                                key={course.id}
                                className="flex items-center gap-2 text-sm font-medium"
                              >
                                <input
                                  type="checkbox"
                                  checked={restrictedCourseIds.includes(course.id)}
                                  onChange={() => {
                                    setRestrictedCourseIds((prev) =>
                                      prev.includes(course.id)
                                        ? prev.filter((id) => id !== course.id)
                                        : [...prev, course.id]
                                    );
                                  }}
                                  className="accent-primary"
                                />
                                <span>{course.title}</span>
                              </label>
                            ))}
                          </div>
                        )}
                      </Field>

                      <Field>
                        <FieldLabel htmlFor="thumbnail">Thumbnail</FieldLabel>
                        <FieldDescription>
                          Upload a new thumbnail image (optional)
                        </FieldDescription>
                        <div className="grid w-full max-w-sm items-center gap-3">
                          <Input
                            id="thumbnail"
                            type="file"
                            accept="image/*"
                            onChange={handleThumbnailChange}
                            className="block w-full text-sm"
                          />

                          {thumbPreview ? (
                            <div className="relative w-40 h-24">
                              <Image
                                src={thumbPreview}
                                alt="Thumbnail preview"
                                fill
                                unoptimized
                                className="object-cover rounded"
                              />
                            </div>
                          ) : null}
                        </div>
                      </Field>

                      <div className="flex gap-2 pt-4">
                        <Button type="submit" disabled={loading}>
                          {loading ? 'Saving...' : 'Save Changes'}
                        </Button>
                        <Button
                          type="button"
                          variant="outline"
                          onClick={() => router.push('/admin/videos')}
                        >
                          Cancel
                        </Button>
                      </div>
                    </FieldGroup>
                  </form>
                </CardContent>
              </Card>
            </div>
          </div>
        </div>
      </SidebarInset>
    </SidebarProvider>
  );
}