"use client"

import { useState, useEffect } from "react"
import { Card, CardContent } from "@/components/ui/card"
import { Button } from "@/components/ui/button"
import { Trophy, TrendingUp, AlertTriangle, Sparkles, Building2, Target, Sliders, CheckCircle2, ChevronRight, UserCheck } from "lucide-react"
import { useActiveUser, isDemoUser } from "@/hooks/useActiveUser"

export default function RankPredictorPage() {
  const { user } = useActiveUser()
  const isDemo = isDemoUser(user?.id)
  const [exam, setExam] = useState<"NEET" | "JEE">("NEET")
  const [physics, setPhysics] = useState(0)
  const [chemistry, setChemistry] = useState(0)
  const [bioOrMath, setBioOrMath] = useState(0)
  const [saved, setSaved] = useState(false)
  const [initialized, setInitialized] = useState(false)

  useEffect(() => {
    if (!user || initialized) return
    const isNeet = user.target_exam ? user.target_exam.includes("NEET") : true
    setExam(isNeet ? "NEET" : "JEE")

    if (isDemo) {
      if (isNeet) {
        setPhysics(140)
        setChemistry(150)
        setBioOrMath(320)
      } else {
        setPhysics(65)
        setChemistry(70)
        setBioOrMath(75)
      }
    } else {
      setPhysics(0)
      setChemistry(0)
      setBioOrMath(0)
    }
    setInitialized(true)
  }, [user, isDemo, initialized])

  const maxTotal = exam === "NEET" ? 720 : 300
  const maxPhysics = exam === "NEET" ? 180 : 100
  const maxChem = exam === "NEET" ? 180 : 100
  const maxThird = exam === "NEET" ? 360 : 100

  const totalScore = physics + chemistry + bioOrMath

  // Calculate predicted rank based on total score percentage
  const calculateRank = (score: number, max: number) => {
    const pct = score / max
    if (pct >= 0.95) return Math.max(12, Math.round((1 - pct) * 2000))
    if (pct >= 0.90) return Math.round(1500 + (0.95 - pct) * 50000)
    if (pct >= 0.80) return Math.round(4000 + (0.90 - pct) * 80000)
    if (pct >= 0.70) return Math.round(12000 + (0.80 - pct) * 120000)
    if (pct >= 0.60) return Math.round(25000 + (0.70 - pct) * 200000)
    return Math.round(60000 + (0.60 - pct) * 400000)
  }

  const predictedRank = calculateRank(totalScore, maxTotal)

  const colleges = exam === "NEET" ? [
    { name: "AIIMS New Delhi", category: "Top Tier Medical", minScore: 690, color: "text-[#00F0FF]", border: "border-[#00F0FF]/30", bg: "bg-[#00F0FF]/10" },
    { name: "MAMC New Delhi", category: "Central GMC", minScore: 665, color: "text-amber-400", border: "border-amber-400/30", bg: "bg-amber-400/10" },
    { name: "KGMU Lucknow / VMMCH", category: "Premier State GMC", minScore: 635, color: "text-emerald-400", border: "border-emerald-400/30", bg: "bg-emerald-400/10" },
    { name: "Top State Govt Medical College", category: "State Quota", minScore: 590, color: "text-purple-400", border: "border-purple-400/30", bg: "bg-purple-400/10" },
  ] : [
    { name: "IIT Bombay / IIT Delhi (CS)", category: "Top 5 IITs", minScore: 260, color: "text-[#00F0FF]", border: "border-[#00F0FF]/30", bg: "bg-[#00F0FF]/10" },
    { name: "IIT Madras / Kharagpur", category: "Core Engineering", minScore: 220, color: "text-amber-400", border: "border-amber-400/30", bg: "bg-amber-400/10" },
    { name: "NIT Trichy / Surathkal", category: "Top NITs", minScore: 180, color: "text-emerald-400", border: "border-emerald-400/30", bg: "bg-emerald-400/10" },
    { name: "Top State Engineering Colleges", category: "State Govt", minScore: 140, color: "text-purple-400", border: "border-purple-400/30", bg: "bg-purple-400/10" },
  ]

  return (
    <div className="p-6 md:p-8 space-y-8 animate-in fade-in duration-500 max-w-7xl mx-auto min-h-screen">
      
      {/* Header */}
      <div className="text-center max-w-3xl mx-auto space-y-3">
        <div className="inline-flex items-center gap-2 px-4 py-1.5 bg-[#00F0FF]/10 text-[#00F0FF] rounded-full border border-[#00F0FF]/30 text-xs font-black tracking-widest uppercase shadow-[0_0_15px_rgba(0,240,255,0.15)]">
          <Sparkles size={14} /> AI Neural Prediction Engine
        </div>
        <h1 className="text-4xl md:text-5xl font-black tracking-tight">AI Rank & College Predictor</h1>
        <p className="text-muted-foreground text-base md:text-lg font-medium">
          Simulate your subject marks to dynamically calculate your All India Rank (AIR) and college admission chances.
        </p>
        {user && (
          <div className="inline-flex items-center gap-2 px-3 py-1 bg-emerald-500/10 text-emerald-400 border border-emerald-500/30 rounded-xl text-xs font-bold mt-1">
            <UserCheck size={14} /> Profile Connected: {user.name.replace(/\s*\([^)]*\)\s*$/, '').trim()} ({user.target_exam?.replace("_", " ")})
          </div>
        )}

        {/* Exam Switcher */}
        <div className="inline-flex p-1.5 bg-secondary/40 border border-border rounded-2xl gap-2 mt-4">
          <button
            onClick={() => {
              setExam("NEET")
              if (isDemo) {
                setPhysics(135)
                setChemistry(155)
                setBioOrMath(330)
              } else {
                setPhysics(0)
                setChemistry(0)
                setBioOrMath(0)
              }
            }}
            className={`px-6 py-2 rounded-xl text-sm font-extrabold transition-all ${
              exam === "NEET" ? "bg-[#00F0FF] text-black shadow-[0_0_15px_#00F0FF]" : "text-muted-foreground hover:text-foreground"
            }`}
          >
            NEET (UG) 720 Marks
          </button>
          <button
            onClick={() => {
              setExam("JEE")
              if (isDemo) {
                setPhysics(65)
                setChemistry(70)
                setBioOrMath(75)
              } else {
                setPhysics(0)
                setChemistry(0)
                setBioOrMath(0)
              }
            }}
            className={`px-6 py-2 rounded-xl text-sm font-extrabold transition-all ${
              exam === "JEE" ? "bg-[#00F0FF] text-black shadow-[0_0_15px_#00F0FF]" : "text-muted-foreground hover:text-foreground"
            }`}
          >
            JEE (Main) 300 Marks
          </button>
        </div>
      </div>

      {/* Main Grid */}
      <div className="grid grid-cols-1 lg:grid-cols-3 gap-8">
        
        {/* Left Interactive Simulator */}
        <div className="lg:col-span-2 space-y-6">
          <Card className="border-border/60 bg-secondary/10 backdrop-blur-xl rounded-3xl p-6 space-y-6 shadow-xl">
            <div className="flex items-center justify-between border-b border-border/40 pb-4">
              <h2 className="text-xl font-extrabold flex items-center gap-2">
                <Sliders className="text-[#00F0FF]" size={20} /> Mark Simulator
              </h2>
              <span className="text-xs font-bold text-muted-foreground uppercase tracking-wider">Drag Sliders to Adjust</span>
            </div>

            {/* Physics Slider */}
            <div className="space-y-2">
              <div className="flex justify-between items-center text-sm font-extrabold">
                <span>Physics Score</span>
                <span className="text-[#00F0FF] text-base">{physics} / {maxPhysics}</span>
              </div>
              <input
                type="range"
                min={0}
                max={maxPhysics}
                value={physics}
                onChange={(e) => setPhysics(Number(e.target.value))}
                className="w-full h-2.5 bg-secondary rounded-lg appearance-none cursor-pointer accent-[#00F0FF]"
              />
            </div>

            {/* Chemistry Slider */}
            <div className="space-y-2">
              <div className="flex justify-between items-center text-sm font-extrabold">
                <span>Chemistry Score</span>
                <span className="text-amber-400 text-base">{chemistry} / {maxChem}</span>
              </div>
              <input
                type="range"
                min={0}
                max={maxChem}
                value={chemistry}
                onChange={(e) => setChemistry(Number(e.target.value))}
                className="w-full h-2.5 bg-secondary rounded-lg appearance-none cursor-pointer accent-amber-400"
              />
            </div>

            {/* Bio / Math Slider */}
            <div className="space-y-2">
              <div className="flex justify-between items-center text-sm font-extrabold">
                <span>{exam === "NEET" ? "Biology Score (Botany + Zoology)" : "Mathematics Score"}</span>
                <span className="text-emerald-400 text-base">{bioOrMath} / {maxThird}</span>
              </div>
              <input
                type="range"
                min={0}
                max={maxThird}
                value={bioOrMath}
                onChange={(e) => setBioOrMath(Number(e.target.value))}
                className="w-full h-2.5 bg-secondary rounded-lg appearance-none cursor-pointer accent-emerald-400"
              />
            </div>

            <div className="p-4 bg-background/50 border border-border/50 rounded-2xl flex items-center justify-between">
              <span className="text-sm font-bold">Simulated Total Score</span>
              <span className="text-3xl font-black text-foreground">{totalScore} <span className="text-sm text-muted-foreground font-semibold">/ {maxTotal}</span></span>
            </div>
          </Card>

          {/* AI Strategy Insights based on Score */}
          <div className="grid grid-cols-1 md:grid-cols-2 gap-4">
            <Card className="p-5 bg-emerald-500/10 border-emerald-500/30 rounded-2xl flex items-start gap-3">
              <TrendingUp className="text-emerald-400 shrink-0 mt-0.5" size={22} />
              <div>
                <h4 className="font-extrabold text-emerald-400">Strongest Domain</h4>
                <p className="text-xs text-muted-foreground font-medium mt-1">
                  {totalScore === 0
                    ? "Baseline Calibrating: Solve your first DPP or CBT to benchmark your subject strengths."
                    : `Your Biology/Math score (${bioOrMath}) provides solid rank leverage. Keep maintaining your revision momentum.`}
                </p>
              </div>
            </Card>

            <Card className="p-5 bg-amber-500/10 border-amber-500/30 rounded-2xl flex items-start gap-3">
              <AlertTriangle className="text-amber-400 shrink-0 mt-0.5" size={22} />
              <div>
                <h4 className="font-extrabold text-amber-400">High-Yield Growth Zone</h4>
                <p className="text-xs text-muted-foreground font-medium mt-1">
                  {totalScore === 0
                    ? "Zero Baseline: Adjust the sliders above or take practice tests to see rank impact in real time."
                    : "Increasing Physics by just 25 marks will boost your rank by approximately ~4,800 positions."}
                </p>
              </div>
            </Card>
          </div>
        </div>

        {/* Right Output Dashboard */}
        <div className="space-y-6">
          
          {/* AIR Display Card */}
          <Card className="border-2 border-[#00F0FF] bg-gradient-to-br from-[#00F0FF]/15 via-secondary/30 to-background rounded-3xl p-6 text-center shadow-[0_0_30px_rgba(0,240,255,0.15)] relative overflow-hidden">
            <div className="absolute top-0 right-0 p-4 opacity-10">
              <Trophy size={120} className="text-[#00F0FF]" />
            </div>
            <div className="text-xs font-black uppercase tracking-widest text-[#00F0FF] mb-2">Estimated All India Rank</div>
            <div className="text-5xl md:text-6xl font-black tracking-tighter text-foreground my-3 filter drop-shadow-md">
              {totalScore === 0 ? "AIR --" : `AIR ~${predictedRank.toLocaleString()}`}
            </div>
            <div className="inline-flex items-center gap-1.5 px-3 py-1 rounded-full bg-[#00F0FF]/20 text-[#00F0FF] text-xs font-bold border border-[#00F0FF]/40">
              <CheckCircle2 size={13} /> {totalScore === 0 ? "Calibrating · Adjust Sliders" : "High Accuracy Confidence"}
            </div>
          </Card>

          {/* College Admission Probability Table */}
          <Card className="border-border/60 bg-secondary/10 backdrop-blur-xl rounded-3xl p-6 space-y-4">
            <h3 className="text-lg font-extrabold flex items-center gap-2">
              <Building2 className="text-[#00F0FF]" size={20} /> College Admission Chances
            </h3>

            {totalScore === 0 ? (
              <div className="p-4 rounded-2xl bg-secondary/20 border border-dashed border-border text-center text-xs text-muted-foreground space-y-1">
                <p className="font-bold text-foreground">No Marks Simulated</p>
                <p>Drag the subject sliders on the left or complete mock tests to view college probability predictions.</p>
              </div>
            ) : (
              <div className="space-y-3">
                {colleges.map((c) => {
                  const isLikely = totalScore >= c.minScore
                  const chancePct = Math.min(99, Math.max(10, Math.round((totalScore / c.minScore) * 85)))
                  return (
                    <div key={c.name} className={`p-3.5 rounded-2xl border ${c.border} ${c.bg} space-y-1.5`}>
                      <div className="flex justify-between items-center">
                        <span className="font-extrabold text-sm text-foreground">{c.name}</span>
                        <span className={`text-xs font-black ${isLikely ? "text-green-400" : "text-amber-400"}`}>
                          {isLikely ? `${chancePct}% Likely` : "Reach Target"}
                        </span>
                      </div>
                      <div className="flex justify-between text-xs text-muted-foreground font-medium">
                        <span>{c.category}</span>
                        <span>Cutoff Score: {c.minScore}+</span>
                      </div>
                    </div>
                  )
                })}
              </div>
            )}
          </Card>

        </div>
      </div>
    </div>
  )
}