'use client';

import { useState, useMemo } from 'react';
import { Card, CardContent, CardHeader, CardTitle } from '@/components/ui/card';
import { Button } from '@/components/ui/button';
import { Badge } from '@/components/ui/badge';
import { ScrollArea } from '@/components/ui/scroll-area';
import { Save, Trash2, Star, ChevronUp } from 'lucide-react';
import { useGameContext } from '../GameContext';
import { SKILLS_DEF } from '@/lib/game/constants';
import { getTierMultiplier, getBaseSkillId } from '@/lib/game/skill-evolution';
import type { Memory } from '@/lib/game/types';

interface MemorySlotPickerProps {
  onConfirm?: () => void;
}

export function MemorySlotPicker({ onConfirm }: MemorySlotPickerProps) {
  const { store } = useGameContext();
  const [selectedSkills, setSelectedSkills] = useState<Memory[]>(store.memories || []);

  // Get all skills that have progress and can be saved
  const saveableSkills = useMemo(() => {
    const skills: { skillId: string; level: number; tier: number; upgrades: string[]; name: string }[] = [];
    
    for (const [skillId, level] of Object.entries(store.skills)) {
      if (level && level > 0) {
        const baseSkillId = getBaseSkillId(skillId);
        const tier = store.skillTiers?.[baseSkillId] || 1;
        const tieredSkillId = tier > 1 ? `${baseSkillId}_t${tier}` : baseSkillId;
        const upgrades = store.skillUpgrades?.[tieredSkillId] || [];
        const skillDef = SKILLS_DEF[baseSkillId];
        
        // Only include if it's a base skill (not a tiered variant in the skills object)
        if (skillId === baseSkillId || skillId.includes('_t')) {
          // Get the actual skill ID and level
          const actualLevel = store.skills[tieredSkillId] || store.skills[baseSkillId] || 0;
          if (actualLevel > 0) {
            skills.push({
              skillId: baseSkillId,
              level: actualLevel,
              tier,
              upgrades,
              name: skillDef?.name || baseSkillId,
            });
          }
        }
      }
    }
    
    // Remove duplicates and keep highest tier/level
    const uniqueSkills = new Map<string, typeof skills[0]>();
    for (const skill of skills) {
      const existing = uniqueSkills.get(skill.skillId);
      if (!existing || skill.tier > existing.tier || (skill.tier === existing.tier && skill.level > existing.level)) {
        uniqueSkills.set(skill.skillId, skill);
      }
    }
    
    return Array.from(uniqueSkills.values()).sort((a, b) => {
      // Sort by tier then level then name
      if (a.tier !== b.tier) return b.tier - a.tier;
      if (a.level !== b.level) return b.level - a.level;
      return a.name.localeCompare(b.name);
    });
  }, [store.skills, store.skillTiers, store.skillUpgrades]);

  const isSkillSelected = (skillId: string) => selectedSkills.some(m => m.skillId === skillId);
  
  const canAddMore = selectedSkills.length < store.memorySlots;

  const toggleSkill = (skillId: string) => {
    const existingIndex = selectedSkills.findIndex(m => m.skillId === skillId);
    
    if (existingIndex >= 0) {
      // Remove it
      setSelectedSkills(selectedSkills.filter((_, i) => i !== existingIndex));
    } else if (canAddMore) {
      // Add it
      const skill = saveableSkills.find(s => s.skillId === skillId);
      if (skill) {
        setSelectedSkills([...selectedSkills, {
          skillId: skill.skillId,
          level: skill.level,
          tier: skill.tier,
          upgrades: skill.upgrades,
        }]);
      }
    }
  };

  const handleConfirm = () => {
    // Clear and re-add selected memories
    store.clearMemories();
    for (const memory of selectedSkills) {
      store.addMemory(memory);
    }
    onConfirm?.();
  };

  return (
    <Card className="bg-gray-900/80 border-gray-700">
      <CardHeader className="pb-2">
        <CardTitle className="text-amber-400 game-panel-title text-sm flex items-center gap-2">
          <Save className="w-4 h-4" />
          Memory Slots ({selectedSkills.length}/{store.memorySlots})
        </CardTitle>
      </CardHeader>
      <CardContent className="space-y-3">
        <p className="text-xs text-gray-400">
          Select skills to preserve in your memory. Saved skills will retain their level, tier, and upgrades in the next loop.
        </p>

        {/* Selected Skills */}
        {selectedSkills.length > 0 && (
          <div className="space-y-1">
            <div className="text-xs text-green-400 game-panel-title">Saved to Memory:</div>
            <div className="flex flex-wrap gap-1">
              {selectedSkills.map((memory) => {
                const skillDef = SKILLS_DEF[memory.skillId];
                return (
                  <Badge
                    key={memory.skillId}
                    className="bg-amber-900/50 text-amber-200 cursor-pointer hover:bg-red-900/50"
                    onClick={() => toggleSkill(memory.skillId)}
                  >
                    {skillDef?.name || memory.skillId}
                    {' '}Lv.{memory.level}
                    {memory.tier > 1 && ` T${memory.tier}`}
                    {memory.upgrades.length > 0 && ` (${memory.upgrades.length}⭐)`}
                    <Trash2 className="w-3 h-3 ml-1" />
                  </Badge>
                );
              })}
            </div>
          </div>
        )}

        {/* Available Skills */}
        <div className="text-xs text-gray-400 game-panel-title">Skills to Save:</div>
        <ScrollArea className="h-48">
          <div className="space-y-1 pr-2">
            {saveableSkills.length === 0 ? (
              <div className="text-gray-500 text-xs text-center py-4">
                No skills with progress to save
              </div>
            ) : (
              saveableSkills.map((skill) => {
                const isSelected = isSkillSelected(skill.skillId);
                const tierMult = getTierMultiplier(skill.tier > 1 ? `${skill.skillId}_t${skill.tier}` : skill.skillId);
                
                return (
                  <div
                    key={skill.skillId}
                    className={`p-2 rounded border cursor-pointer transition-all ${
                      isSelected
                        ? 'border-amber-500 bg-amber-900/30'
                        : canAddMore
                          ? 'border-gray-700 bg-gray-800/50 hover:border-gray-600'
                          : 'border-gray-800 bg-gray-900/30 opacity-50'
                    }`}
                    onClick={() => toggleSkill(skill.skillId)}
                  >
                    <div className="flex items-center justify-between">
                      <div className="flex items-center gap-2">
                        <span className="font-semibold text-sm">{skill.name}</span>
                        {skill.tier > 1 && (
                          <Badge className="bg-purple-600/50 text-purple-200 text-xs">
                            Tier {skill.tier} ({tierMult}x)
                          </Badge>
                        )}
                      </div>
                      <div className="flex items-center gap-2">
                        <span className="text-purple-400 text-sm">Lv.{skill.level}</span>
                        {skill.upgrades.length > 0 && (
                          <Badge className="bg-amber-700/50 text-amber-200 text-xs flex items-center gap-1">
                            <Star className="w-3 h-3" />
                            {skill.upgrades.length}
                          </Badge>
                        )}
                      </div>
                    </div>
                    {skill.upgrades.length > 0 && (
                      <div className="text-xs text-gray-500 mt-1">
                        Upgrades: {skill.upgrades.length} selected
                      </div>
                    )}
                  </div>
                );
              })
            )}
          </div>
        </ScrollArea>

        {/* Confirm Button */}
        <Button
          className="w-full bg-amber-600 hover:bg-amber-700"
          onClick={handleConfirm}
        >
          <Save className="w-4 h-4 mr-2" />
          Confirm Memories
        </Button>
      </CardContent>
    </Card>
  );
}