'use client';

import { useState, useEffect, useCallback } from 'react';
import { useShallow } from 'zustand/react/shallow';
import { usePrestigeStore, useGameStore } from '@/lib/game/stores';
import { PRESTIGE_DEF } from '@/lib/game/constants/prestige';
import { Card, CardContent } from '@/components/ui/card';
import { Button } from '@/components/ui/button';
import { Badge } from '@/components/ui/badge';
import { ScrollArea } from '@/components/ui/scroll-area';
import { SectionHeader } from '@/components/ui/section-header';
import { DebugName } from '@/components/game/debug/debug-context';
import { fmt } from '@/lib/game/stores';
import {
  AlertDialog,
  AlertDialogAction,
  AlertDialogCancel,
  AlertDialogContent,
  AlertDialogDescription,
  AlertDialogFooter,
  AlertDialogHeader,
  AlertDialogTitle,
  AlertDialogTrigger,
} from '@/components/ui/alert-dialog';

// ─── Stat Cell ────────────────────────────────────────────────────────────────

function PrestigeStatCell({ value, label, color }: { value: string | number; label: string; color: string }) {
  return (
    <div className="text-center">
      <div className={`text-2xl font-bold ${color}`}>{value}</div>
      <div className="text-xs text-gray-400 mt-0.5">{label}</div>
    </div>
  );
}

// ─── Insight Summary ──────────────────────────────────────────────────────────

function InsightSummary({ insight, totalInsight, loopCount, loopInsight }: {
  insight: number;
  totalInsight: number;
  loopCount: number;
  loopInsight: number;
}) {
  return (
    <Card className="bg-gray-900/60 border-gray-700">
      <CardContent className="py-4">
        <div className="grid grid-cols-2 md:grid-cols-4 gap-4">
          <PrestigeStatCell value={fmt(insight)} label="Insight Available" color="text-amber-400" />
          <PrestigeStatCell value={fmt(totalInsight)} label="Total Insight Earned" color="text-gray-200" />
          <PrestigeStatCell value={loopCount} label="Loops Completed" color="text-gray-200" />
          <PrestigeStatCell value={fmt(loopInsight)} label="This Loop's Insight" color="text-purple-400" />
        </div>
      </CardContent>
    </Card>
  );
}

// ─── Memories Card ────────────────────────────────────────────────────────────

function MemoriesCard({ memories, memorySlots }: { memories: { skillId: string; level: number; tier: number }[]; memorySlots: number }) {
  return (
    <Card className="bg-gray-900/60 border-gray-700">
      <SectionHeader title="🧠 Memories" />
      <CardContent className="pt-0">
        <p className="text-xs text-gray-400 mb-2">
          Skills carried between loops. Slots: {memories.length}/{memorySlots}
        </p>
        {memories.length === 0 ? (
          <p className="text-xs text-gray-500 italic">No memories stored yet.</p>
        ) : (
          <div className="space-y-1">
            {memories.map((m) => (
              <div key={m.skillId} className="text-xs text-gray-300 flex justify-between">
                <span>{m.skillId}</span>
                <span className="text-gray-500">Lv.{m.level} T{m.tier}</span>
              </div>
            ))}
          </div>
        )}
      </CardContent>
    </Card>
  );
}

// ─── Pacts Card ───────────────────────────────────────────────────────────────

function PactsCard({ signedPacts, pactSlots, defeatedGuardians }: {
  signedPacts: number[];
  pactSlots: number;
  defeatedGuardians: number[];
}) {
  return (
    <Card className="bg-gray-900/60 border-gray-700">
      <SectionHeader title="📜 Pacts" />
      <CardContent className="pt-0">
        <p className="text-xs text-gray-400 mb-2">
          Guardian pacts signed. Slots: {signedPacts.length}/{pactSlots}
        </p>
        {defeatedGuardians.length > 0 && (
          <p className="text-xs text-gray-500 mb-1">
            Defeated guardians: {defeatedGuardians.map((f) => `F${f}`).join(', ')}
          </p>
        )}
        {signedPacts.length === 0 ? (
          <p className="text-xs text-gray-500 italic">No pacts signed yet.</p>
        ) : (
          <div className="space-y-1">
            {signedPacts.map((f) => (
              <div key={f} className="text-xs text-green-400">
                ✓ Floor {f} — Pact signed
              </div>
            ))}
          </div>
        )}
      </CardContent>
    </Card>
  );
}

// ─── Upgrade Card ─────────────────────────────────────────────────────────────

interface UpgradeCardProps {
  id: string;
  name: string;
  desc: string;
  max: number;
  cost: number;
  currentLevel: number;
  insight: number;
  onPurchase: (id: string) => void;
}

function UpgradeCard({ id, name, desc, max, cost, currentLevel, insight, onPurchase }: UpgradeCardProps) {
  const isMaxed = currentLevel >= max;
  const canAfford = insight >= cost;
  const disabled = isMaxed || !canAfford;

  return (
    <Card className={`bg-gray-900/60 ${isMaxed ? 'border-amber-700/50' : 'border-gray-700'}`}>
      <CardContent className="p-4 space-y-2">
        <div className="flex items-center justify-between">
          <span className="font-medium text-sm text-gray-100">{name}</span>
          <Badge
            variant="outline"
            className={isMaxed ? 'border-amber-600 text-amber-400' : 'border-gray-600 text-gray-400'}
          >
            {currentLevel}/{max}
          </Badge>
        </div>
        <p className="text-xs text-gray-400">{desc}</p>
        <div className="flex items-center justify-between pt-1">
          <span className="text-xs text-gray-500">
            Cost: <span className={canAfford ? 'text-amber-400' : 'text-red-400'}>{fmt(cost)}</span> insight
          </span>
          <Button
            size="sm"
            disabled={disabled}
            onClick={() => onPurchase(id)}
            className="h-7 px-3 text-xs"
          >
            {isMaxed ? 'Maxed' : 'Buy'}
          </Button>
        </div>
      </CardContent>
    </Card>
  );
}

// ─── Reset Loop Section ──────────────────────────────────────────────────────

function ResetLoopSection({ loopInsight, onReset }: { loopInsight: number; onReset: () => void }) {
  return (
    <Card className="bg-gray-900/60 border-red-900/50">
      <CardContent className="py-4">
        <div className="flex items-center justify-between">
          <div>
            <h3 className="text-lg font-semibold text-red-400">Reset Loop</h3>
            <p className="text-xs text-gray-400 mt-1">
              End the current loop and gain {fmt(loopInsight)} insight. Your prestige upgrades, memories, and pacts are preserved.
            </p>
          </div>
          <AlertDialog>
            <AlertDialogTrigger asChild>
              <Button variant="destructive" size="sm" className="flex-shrink-0 ml-4">
                Reset Loop
              </Button>
            </AlertDialogTrigger>
            <AlertDialogContent>
              <AlertDialogHeader>
                <AlertDialogTitle>Reset the Loop?</AlertDialogTitle>
                <AlertDialogDescription>
                  This will end your current loop and award you <strong className="text-amber-400">{fmt(loopInsight)} insight</strong>.
                  Your prestige upgrades, memories, and pacts will be preserved.
                  <br /><br />
                  Day, hour, mana, floor progress, and combat state will be reset.
                </AlertDialogDescription>
              </AlertDialogHeader>
              <AlertDialogFooter>
                <AlertDialogCancel>Cancel</AlertDialogCancel>
                <AlertDialogAction onClick={onReset}>
                  Confirm Reset
                </AlertDialogAction>
              </AlertDialogFooter>
            </AlertDialogContent>
          </AlertDialog>
        </div>
      </CardContent>
    </Card>
  );
}

// ─── Main Component ───────────────────────────────────────────────────────────

export function PrestigeTab() {
  const [mounted, setMounted] = useState(false);

  const {
    insight,
    totalInsight,
    loopInsight,
    loopCount,
    prestigeUpgrades,
    memorySlots,
    memories,
    pactSlots,
    signedPacts,
    defeatedGuardians,
    doPrestige,
  } = usePrestigeStore(useShallow((s) => ({
    insight: s.insight,
    totalInsight: s.totalInsight,
    loopInsight: s.loopInsight,
    loopCount: s.loopCount,
    prestigeUpgrades: s.prestigeUpgrades,
    memorySlots: s.memorySlots,
    memories: s.memories,
    pactSlots: s.pactSlots,
    signedPacts: s.signedPacts,
    defeatedGuardians: s.defeatedGuardians,
    doPrestige: s.doPrestige,
  })));

  const startNewLoop = useGameStore((s) => s.startNewLoop);

  useEffect(() => {
    setMounted(true);
  }, []);

  const handlePurchase = useCallback((id: string) => {
    doPrestige(id);
  }, [doPrestige]);

  const handleResetLoop = useCallback(() => {
    startNewLoop();
  }, [startNewLoop]);

  if (!mounted) {
    return (
      <div className="flex items-center justify-center p-8 text-gray-500">
        Loading prestige…
      </div>
    );
  }

  const upgradeEntries = Object.entries(PRESTIGE_DEF);

  return (
    <DebugName name="PrestigeTab">
      <div className="space-y-4">
        <InsightSummary
          insight={insight}
          totalInsight={totalInsight}
          loopCount={loopCount}
          loopInsight={loopInsight}
        />

        <div className="grid grid-cols-1 md:grid-cols-2 gap-4">
          <MemoriesCard memories={memories} memorySlots={memorySlots} />
          <PactsCard signedPacts={signedPacts} pactSlots={pactSlots} defeatedGuardians={defeatedGuardians} />
        </div>

        <Card className="bg-gray-900/60 border-gray-700">
          <SectionHeader title="⬆️ Prestige Upgrades" />
          <CardContent className="pt-0">
            <ScrollArea className="h-[400px] pr-2">
              <div className="grid grid-cols-1 md:grid-cols-2 gap-3">
                {upgradeEntries.map(([id, def]) => (
                  <UpgradeCard
                    key={id}
                    id={id}
                    name={def.name}
                    desc={def.desc}
                    max={def.max}
                    cost={def.cost}
                    currentLevel={prestigeUpgrades[id] || 0}
                    insight={insight}
                    onPurchase={handlePurchase}
                  />
                ))}
              </div>
            </ScrollArea>
          </CardContent>
        </Card>

        <ResetLoopSection loopInsight={loopInsight} onReset={handleResetLoop} />
      </div>
    </DebugName>
  );
}

PrestigeTab.displayName = 'PrestigeTab';