import { useCallback, type CSSProperties } from 'react';
import type { NPCData } from '../game/types';

// ---- Types ----

interface NPCInteractionProps {
  npc: NPCData;
  heroGold: number;
  potionCost: number;
  healCost: number;
  onViewQuests: (npc: NPCData) => void;
  onBuyPotion: (npc: NPCData) => void;
  onHeal: (npc: NPCData) => void;
  onDismiss: () => void;
}

// ---- Styles ----

const panelStyle: CSSProperties = {
  position: 'absolute',
  bottom: 130,
  left: '50%',
  transform: 'translateX(-50%)',
  minWidth: 220,
  maxWidth: 320,
  backgroundColor: 'rgba(15, 15, 25, 0.94)',
  border: '1px solid rgba(255, 215, 0, 0.3)',
  borderRadius: 12,
  padding: '10px 14px 12px',
  zIndex: 120,
  pointerEvents: 'auto',
  animation: 'npc-interact-fade-in 0.25s ease-out',
  boxShadow: '0 4px 20px rgba(0, 0, 0, 0.5)',
};

const headerRow: CSSProperties = {
  display: 'flex',
  alignItems: 'center',
  gap: 8,
  marginBottom: 8,
};

const npcIconStyle: CSSProperties = {
  width: 28,
  height: 28,
  borderRadius: 14,
  display: 'flex',
  alignItems: 'center',
  justifyContent: 'center',
  fontSize: 14,
  fontWeight: 700,
};

const npcNameStyle: CSSProperties = {
  fontSize: 13,
  fontWeight: 700,
  color: '#e8e8e8',
  flex: 1,
};

const npcTypeStyle: CSSProperties = {
  fontSize: 9,
  fontWeight: 600,
  color: '#888',
  textTransform: 'uppercase',
  letterSpacing: 0.5,
};

const actionBtnStyle: CSSProperties = {
  width: '100%',
  padding: '8px 12px',
  border: 'none',
  borderRadius: 8,
  fontSize: 12,
  fontWeight: 600,
  cursor: 'pointer',
  marginBottom: 4,
  transition: 'background-color 150ms ease',
  textAlign: 'center',
};

// ---- NPC appearance ----

function npcColor(type: string): { bg: string; icon: string; text: string } {
  switch (type) {
    case 'quest_giver':
      return { bg: 'rgba(218, 165, 32, 0.2)', icon: '!', text: 'Quest Giver' };
    case 'merchant':
      return { bg: 'rgba(68, 170, 85, 0.2)', icon: '$', text: 'Merchant' };
    case 'healer':
      return { bg: 'rgba(220, 80, 80, 0.2)', icon: '+', text: 'Healer' };
    default:
      return { bg: 'rgba(136, 136, 170, 0.2)', icon: '?', text: 'NPC' };
  }
}

// ---- Component ----

export function NPCInteraction({
  npc,
  heroGold,
  potionCost,
  healCost,
  onViewQuests,
  onBuyPotion,
  onHeal,
  onDismiss,
}: NPCInteractionProps) {
  const info = npcColor(npc.type);

  const handleAction = useCallback(() => {
    switch (npc.type) {
      case 'quest_giver':
        onViewQuests(npc);
        break;
      case 'merchant':
        onBuyPotion(npc);
        break;
      case 'healer':
        onHeal(npc);
        break;
    }
  }, [npc, onViewQuests, onBuyPotion, onHeal]);

  const actionLabel = (() => {
    switch (npc.type) {
      case 'quest_giver':
        return 'View Quests';
      case 'merchant':
        return `Buy Potion (${potionCost}g)`;
      case 'healer':
        return `Heal to Full (${healCost}g)`;
      default:
        return 'Talk';
    }
  })();

  const canAfford =
    npc.type === 'quest_giver' ||
    (npc.type === 'merchant' && heroGold >= potionCost) ||
    (npc.type === 'healer' && heroGold >= healCost);

  return (
    <>
      <style>{`
        @keyframes npc-interact-fade-in {
          0%   { opacity: 0; transform: translateX(-50%) translateY(8px); }
          100% { opacity: 1; transform: translateX(-50%) translateY(0); }
        }
      `}</style>
      <div style={panelStyle}>
        <div style={headerRow}>
          <div
            style={{
              ...npcIconStyle,
              backgroundColor: info.bg,
              color: npc.type === 'quest_giver' ? '#ffd700' :
                     npc.type === 'merchant' ? '#88dd88' :
                     npc.type === 'healer' ? '#ff6666' : '#aaa',
            }}
          >
            {info.icon}
          </div>
          <div>
            <div style={npcNameStyle}>{npc.name}</div>
            <div style={npcTypeStyle}>{info.text}</div>
          </div>
          <button
            onClick={onDismiss}
            style={{
              background: 'none',
              border: 'none',
              color: '#666',
              fontSize: 16,
              cursor: 'pointer',
              padding: '2px 6px',
              lineHeight: 1,
            }}
          >
            {'\u2715'}
          </button>
        </div>

        <button
          style={{
            ...actionBtnStyle,
            backgroundColor: canAfford
              ? (npc.type === 'quest_giver' ? 'rgba(68, 170, 255, 0.2)' :
                 npc.type === 'merchant' ? 'rgba(68, 200, 68, 0.2)' :
                 'rgba(200, 68, 68, 0.2)')
              : 'rgba(100, 100, 100, 0.15)',
            color: canAfford
              ? (npc.type === 'quest_giver' ? '#66bbff' :
                 npc.type === 'merchant' ? '#88dd88' :
                 '#ff8888')
              : '#666',
            opacity: canAfford ? 1 : 0.5,
            cursor: canAfford ? 'pointer' : 'default',
          }}
          onClick={canAfford ? handleAction : undefined}
          disabled={!canAfford}
        >
          {actionLabel}
        </button>
      </div>
    </>
  );
}
