import { useState, useMemo } from "react";
import { useParams } from "react-router-dom";
import { Card, CardContent, CardHeader, CardTitle, CardDescription } from "@/components/ui/card";
import { Button } from "@/components/ui/button";
import { Input } from "@/components/ui/input";
import { Label } from "@/components/ui/label";
import { Textarea } from "@/components/ui/textarea";
import { Badge } from "@/components/ui/badge";
import { Select, SelectContent, SelectItem, SelectTrigger, SelectValue } from "@/components/ui/select";
import { Loader2, Sparkles, ChevronRight, CheckCircle2, BookOpen } from "lucide-react";
import { useGenerateOutline, useGenerateChapterContent, usePublishWorkbench } from "@/hooks/queries";
import { useToast } from "@/hooks/use-toast";
import type { WorkbenchGeneratedOutline, WorkbenchGeneratedChapter } from "@/types/courseware";

function sanitizeHtml(dirty: string): string {
  const div = document.createElement("div");
  div.textContent = "";
  const parser = new DOMParser();
  const doc = parser.parseFromString(dirty, "text/html");
  const scripts = doc.querySelectorAll("script, iframe, object, embed, link[rel=import]");
  scripts.forEach((el) => el.remove());
  doc.querySelectorAll("*").forEach((el) => {
    for (const attr of Array.from(el.attributes)) {
      if (attr.name.startsWith("on") || attr.value.trim().toLowerCase().startsWith("javascript:")) {
        el.removeAttribute(attr.name);
      }
    }
  });
  return doc.body.innerHTML;
}

type Complexity = "beginner" | "intermediate" | "advanced";

export default function AiWorkbench() {
  const { courseId } = useParams<{ courseId: string }>();
  const cid = Number(courseId);
  const { toast } = useToast();

  const [step, setStep] = useState(1);
  const [topic, setTopic] = useState("");
  const [objectives, setObjectives] = useState("");
  const [complexity, setComplexity] = useState<Complexity>("intermediate");
  const [outline, setOutline] = useState<WorkbenchGeneratedOutline | null>(null);
  const [generatedContent, setGeneratedContent] = useState<WorkbenchGeneratedChapter | null>(null);

  const generateOutline = useGenerateOutline();
  const generateContent = useGenerateChapterContent();
  const publishWorkbench = usePublishWorkbench();

  const handleGenerateOutline = () => {
    generateOutline.mutate(
      { course_id: cid, topic, objectives, complexity },
      {
        onSuccess: (data) => { setOutline(data); setStep(2); },
        onError: () => toast({ title: "Error", description: "Failed to generate outline", variant: "destructive" }),
      },
    );
  };

  const handleGenerateContent = () => {
    generateContent.mutate(
      { course_id: cid, topic, objectives, complexity },
      {
        onSuccess: (data) => { setGeneratedContent(data); setStep(3); },
        onError: () => toast({ title: "Error", description: "Failed to generate content", variant: "destructive" }),
      },
    );
  };

  const handlePublish = () => {
    publishWorkbench.mutate(
      { course_id: cid, topic, objectives, complexity, outline, content: generatedContent },
      {
        onSuccess: () => { toast({ title: "Published Successfully" }); setStep(4); },
        onError: () => toast({ title: "Error", description: "Failed to publish", variant: "destructive" }),
      },
    );
  };

  const steps = [
    { num: 1, label: "Requirements" },
    { num: 2, label: "Review Outline" },
    { num: 3, label: "Generated Content" },
    { num: 4, label: "Published" },
  ];

  return (
    <div className="space-y-6">
      <div>
        <h1 className="text-2xl font-bold">AI Workbench</h1>
        <p className="text-muted-foreground">Generate course content using AI assistance.</p>
      </div>

      <div className="flex items-center gap-2">
        {steps.map((s, i) => (
          <div key={s.num} className="flex items-center">
            <div className={`flex items-center gap-2 px-3 py-1.5 rounded-full text-sm ${step >= s.num ? "bg-primary/10 text-primary font-medium" : "text-muted-foreground"}`}>
              {step > s.num ? <CheckCircle2 className="h-4 w-4" /> : <span className="h-5 w-5 rounded-full border flex items-center justify-center text-xs">{s.num}</span>}
              {s.label}
            </div>
            {i < steps.length - 1 && <ChevronRight className="h-4 w-4 text-muted-foreground mx-1" />}
          </div>
        ))}
      </div>

      {step === 1 && (
        <Card>
          <CardHeader>
            <CardTitle>Input Requirements</CardTitle>
            <CardDescription>Describe what content you want the AI to generate.</CardDescription>
          </CardHeader>
          <CardContent className="space-y-4">
            <div className="space-y-2">
              <Label>Topic</Label>
              <Input placeholder="e.g. Introduction to Calculus" value={topic} onChange={e => setTopic(e.target.value)} />
            </div>
            <div className="space-y-2">
              <Label>Learning Objectives</Label>
              <Textarea placeholder="List the key objectives, one per line..." rows={4} value={objectives} onChange={e => setObjectives(e.target.value)} />
            </div>
            <div className="space-y-2">
              <Label>Complexity Level</Label>
              <Select value={complexity} onValueChange={v => setComplexity(v as Complexity)}>
                <SelectTrigger><SelectValue /></SelectTrigger>
                <SelectContent>
                  <SelectItem value="beginner">Beginner</SelectItem>
                  <SelectItem value="intermediate">Intermediate</SelectItem>
                  <SelectItem value="advanced">Advanced</SelectItem>
                </SelectContent>
              </Select>
            </div>
            <Button onClick={handleGenerateOutline} disabled={generateOutline.isPending || !topic || !objectives}>
              {generateOutline.isPending && <Loader2 className="mr-2 h-4 w-4 animate-spin" />}
              <Sparkles className="mr-2 h-4 w-4" /> Generate Outline
            </Button>
          </CardContent>
        </Card>
      )}

      {step === 2 && outline && (
        <Card>
          <CardHeader>
            <CardTitle>Review Generated Outline</CardTitle>
            <CardDescription>Review the AI-generated chapter outline before generating detailed content.</CardDescription>
          </CardHeader>
          <CardContent className="space-y-4">
            {outline.chapters.map((ch, i) => (
              <div key={i} className="p-4 rounded-lg border space-y-2">
                <div className="flex items-center gap-2">
                  <BookOpen className="h-4 w-4 text-primary" />
                  <span className="font-medium">{ch.name}</span>
                  <Badge variant="outline">{ch.estimated_duration_hours}h</Badge>
                </div>
                <p className="text-sm text-muted-foreground">{ch.description}</p>
                <div className="flex flex-wrap gap-1">
                  {ch.learning_outcomes.map((lo, j) => (
                    <Badge key={j} variant="secondary" className="text-xs">{lo}</Badge>
                  ))}
                </div>
              </div>
            ))}
            <div className="flex gap-2">
              <Button variant="outline" onClick={() => setStep(1)}>Back</Button>
              <Button onClick={handleGenerateContent} disabled={generateContent.isPending}>
                {generateContent.isPending && <Loader2 className="mr-2 h-4 w-4 animate-spin" />}
                Generate Content
              </Button>
            </div>
          </CardContent>
        </Card>
      )}

      {step === 3 && generatedContent && (
        <Card>
          <CardHeader>
            <CardTitle>Generated Content</CardTitle>
            <CardDescription>Review the detailed content before publishing.</CardDescription>
          </CardHeader>
          <CardContent className="space-y-4">
            <div className="prose prose-sm max-w-none p-4 rounded-lg border bg-muted/30" dangerouslySetInnerHTML={{ __html: sanitizeHtml(generatedContent.content) }} />
            {generatedContent.exercises.length > 0 && (
              <div className="space-y-2">
                <h3 className="font-medium">Exercises ({generatedContent.exercises.length})</h3>
                {generatedContent.exercises.map((ex, i) => (
                  <div key={i} className="p-3 rounded border text-sm">
                    <p className="font-medium">{ex.question}</p>
                    <p className="text-muted-foreground mt-1">{ex.answer}</p>
                    <Badge variant="outline" className="mt-1 text-xs">{ex.type}</Badge>
                  </div>
                ))}
              </div>
            )}
            <div className="flex gap-2">
              <Button variant="outline" onClick={() => setStep(2)}>Back</Button>
              <Button onClick={handlePublish} disabled={publishWorkbench.isPending}>
                {publishWorkbench.isPending && <Loader2 className="mr-2 h-4 w-4 animate-spin" />}
                Publish
              </Button>
            </div>
          </CardContent>
        </Card>
      )}

      {step === 4 && (
        <Card>
          <CardContent className="py-12 text-center">
            <CheckCircle2 className="h-12 w-12 text-green-500 mx-auto mb-3" />
            <h2 className="text-xl font-semibold">Content Published!</h2>
            <p className="text-muted-foreground mt-1">The AI-generated content has been added to your course.</p>
            <Button variant="outline" className="mt-4" onClick={() => { setStep(1); setOutline(null); setGeneratedContent(null); setTopic(""); setObjectives(""); }}>
              Generate More
            </Button>
          </CardContent>
        </Card>
      )}
    </div>
  );
}