'use client';

import { useState } from 'react';
import { SKILLS_DEF, SKILL_CATEGORIES, getStudySpeedMultiplier, getStudyCostMultiplier } from '@/lib/game/constants';
import { SKILL_EVOLUTION_PATHS, getUpgradesForSkillAtMilestone, getNextTierSkill, getTierMultiplier } from '@/lib/game/skill-evolution';
import { getUnifiedEffects, hasSpecial, SPECIAL_EFFECTS } from '@/lib/game/effects';
import { getAvailableSkillCategories } from '@/lib/game/data/attunements';
import { fmt, fmtDec } from '@/lib/game/store';
import { formatStudyTime } from '@/lib/game/formatting';
import type { SkillUpgradeChoice, GameStore } from '@/lib/game/types';
import { Button } from '@/components/ui/button';
import { Card, CardContent, CardHeader, CardTitle } from '@/components/ui/card';
import { Badge } from '@/components/ui/badge';
import { Tooltip, TooltipContent, TooltipProvider, TooltipTrigger } from '@/components/ui/tooltip';
import { StudyProgress } from './StudyProgress';
import { UpgradeDialog } from './UpgradeDialog';
import { ChevronDown, ChevronRight } from 'lucide-react';

export interface SkillsTabProps {
  store: GameStore;
}

// Check if skill has milestone available
function hasMilestoneUpgrade(
  skillId: string, 
  level: number, 
  skillTiers: Record<string, number>,
  skillUpgrades: Record<string, string[]>
): { milestone: 5 | 10; hasUpgrades: boolean; selectedCount: number } | null {
  const baseSkillId = skillId.includes('_t') ? skillId.split('_t')[0] : skillId;
  const path = SKILL_EVOLUTION_PATHS[baseSkillId];
  if (!path) return null;
  
  // Check level 5 milestone
  if (level >= 5) {
    const upgrades5 = getUpgradesForSkillAtMilestone(skillId, 5, skillTiers);
    const selected5 = (skillUpgrades[skillId] || []).filter(id => id.includes('_l5'));
    if (upgrades5.length > 0 && selected5.length < 2) {
      return { milestone: 5, hasUpgrades: true, selectedCount: selected5.length };
    }
  }
  
  // Check level 10 milestone
  if (level >= 10) {
    const upgrades10 = getUpgradesForSkillAtMilestone(skillId, 10, skillTiers);
    const selected10 = (skillUpgrades[skillId] || []).filter(id => id.includes('_l10'));
    if (upgrades10.length > 0 && selected10.length < 2) {
      return { milestone: 10, hasUpgrades: true, selectedCount: selected10.length };
    }
  }
  
  return null;
}

export function SkillsTab({ store }: SkillsTabProps) {
  const [upgradeDialogSkill, setUpgradeDialogSkill] = useState<string | null>(null);
  const [upgradeDialogMilestone, setUpgradeDialogMilestone] = useState<5 | 10>(5);
  const [pendingUpgradeSelections, setPendingUpgradeSelections] = useState<string[]>([]);
  const [collapsedCategories, setCollapsedCategories] = useState<Set<string>>(new Set());
  
  const studySpeedMult = getStudySpeedMultiplier(store.skills);
  const upgradeEffects = getUnifiedEffects(store);
  
  // Toggle category collapse
  const toggleCategory = (categoryId: string) => {
    setCollapsedCategories(prev => {
      const newSet = new Set(prev);
      if (newSet.has(categoryId)) {
        newSet.delete(categoryId);
      } else {
        newSet.add(categoryId);
      }
      return newSet;
    });
  };
  
  // Get upgrade choices for dialog
  const getUpgradeChoices = () => {
    if (!upgradeDialogSkill) return { available: [] as SkillUpgradeChoice[], selected: [] as string[] };
    return store.getSkillUpgradeChoices(upgradeDialogSkill, upgradeDialogMilestone);
  };
  
  const { available, selected: alreadySelected } = getUpgradeChoices();
  
  // Toggle selection
  const toggleUpgrade = (upgradeId: string) => {
    const currentSelections = pendingUpgradeSelections.length > 0 ? pendingUpgradeSelections : alreadySelected;
    if (currentSelections.includes(upgradeId)) {
      setPendingUpgradeSelections(currentSelections.filter(id => id !== upgradeId));
    } else if (currentSelections.length < 2) {
      setPendingUpgradeSelections([...currentSelections, upgradeId]);
    }
  };
  
  // Commit selections and close
  const handleConfirm = () => {
    const currentSelections = pendingUpgradeSelections.length > 0 ? pendingUpgradeSelections : alreadySelected;
    if (currentSelections.length === 2 && upgradeDialogSkill) {
      store.commitSkillUpgrades(upgradeDialogSkill, currentSelections, upgradeDialogMilestone);
    }
    setPendingUpgradeSelections([]);
    setUpgradeDialogSkill(null);
  };
  
  // Cancel and close
  const handleCancel = () => {
    setPendingUpgradeSelections([]);
    setUpgradeDialogSkill(null);
  };
  
  return (
    <div className="space-y-4">
      {/* Upgrade Selection Dialog */}
      <UpgradeDialog
        open={!!upgradeDialogSkill}
        skillId={upgradeDialogSkill}
        milestone={upgradeDialogMilestone}
        pendingSelections={pendingUpgradeSelections}
        available={available}
        alreadySelected={alreadySelected}
        onToggle={toggleUpgrade}
        onConfirm={handleConfirm}
        onCancel={handleCancel}
        onOpenChange={(open) => {
          if (!open) {
            setPendingUpgradeSelections([]);
            setUpgradeDialogSkill(null);
          }
        }}
      />
      
      {/* Current Study Progress */}
      {store.currentStudyTarget && store.currentStudyTarget.type === 'skill' && (
        <Card className="bg-gray-900/80 border-purple-600/50">
          <CardContent className="pt-4">
            <StudyProgress
              currentStudyTarget={store.currentStudyTarget}
              skills={store.skills}
              studySpeedMult={studySpeedMult}
              cancelStudy={store.cancelStudy}
            />
          </CardContent>
        </Card>
      )}
      
      {/* Get available skill categories based on attunements */}
      {(() => {
        const availableCategories = getAvailableSkillCategories(store.attunements || {});
        
        return SKILL_CATEGORIES
          .filter(cat => availableCategories.includes(cat.id))
          .map((cat) => {
            const skillsInCat = Object.entries(SKILLS_DEF).filter(([, def]) => def.cat === cat.id);
            if (skillsInCat.length === 0) return null;
            
            const isCollapsed = collapsedCategories.has(cat.id);
            
            return (
          <Card key={cat.id} className="bg-gray-900/80 border-gray-700">
            <CardHeader className="pb-2 cursor-pointer" onClick={() => toggleCategory(cat.id)}>
              <CardTitle className="text-amber-400 game-panel-title text-xs flex items-center justify-between">
                <span>{cat.icon} {cat.name}</span>
                <div className="flex items-center gap-2">
                  <Badge variant="outline" className="text-xs">{skillsInCat.length} skills</Badge>
                  {isCollapsed ? <ChevronRight className="w-4 h-4" /> : <ChevronDown className="w-4 h-4" />}
                </div>
              </CardTitle>
            </CardHeader>
            {!isCollapsed && (
            <CardContent>
              <div className="space-y-2">
                {skillsInCat.map(([id, def]) => {
                  // Get tier info
                  const currentTier = store.skillTiers?.[id] || 1;
                  const tieredSkillId = currentTier > 1 ? `${id}_t${currentTier}` : id;
                  const tierMultiplier = getTierMultiplier(tieredSkillId);
                  
                  // Get the actual level from the tiered skill
                  const level = store.skills[tieredSkillId] || store.skills[id] || 0;
                  const maxed = level >= def.max;
                  
                  // Check if studying this skill
                  const isStudying = (store.currentStudyTarget?.id === id || store.currentStudyTarget?.id === tieredSkillId) && store.currentStudyTarget?.type === 'skill';
                  
                  // Get tier name for display
                  const tierDef = SKILL_EVOLUTION_PATHS[id]?.tiers.find(t => t.tier === currentTier);
                  const skillDisplayName = tierDef?.name || def.name;
                  
                  // Check prerequisites
                  let prereqMet = true;
                  if (def.req) {
                    for (const [r, rl] of Object.entries(def.req)) {
                      if ((store.skills[r] || 0) < rl) {
                        prereqMet = false;
                        break;
                      }
                    }
                  }
                  
                  // Apply skill modifiers
                  const costMult = getStudyCostMultiplier(store.skills);
                  const speedMult = getStudySpeedMultiplier(store.skills);
                  const studyEffects = getUnifiedEffects(store);
                  const effectiveSpeedMult = speedMult * studyEffects.studySpeedMultiplier;
                  
                  // Study time scales with tier
                  const tierStudyTime = def.studyTime * currentTier;
                  const effectiveStudyTime = tierStudyTime / effectiveSpeedMult;
                  
                  // Cost scales with tier
                  const baseCost = def.base * (level + 1) * currentTier;
                  const cost = Math.floor(baseCost * costMult);
                  
                  // Can start studying?
                  const canStudy = !maxed && prereqMet && store.rawMana >= cost && !isStudying;
                  
                  // Check for milestone upgrades
                  const milestoneInfo = hasMilestoneUpgrade(tieredSkillId, level, store.skillTiers || {}, store.skillUpgrades);
                  
                  // Check for tier up
                  const nextTierSkill = getNextTierSkill(tieredSkillId);
                  const canTierUp = maxed && nextTierSkill;
                  
                  // Get selected upgrades
                  const selectedUpgrades = store.skillUpgrades[tieredSkillId] || [];
                  const selectedL5 = selectedUpgrades.filter(u => u.includes('_l5'));
                  const selectedL10 = selectedUpgrades.filter(u => u.includes('_l10'));
                  
                  return (
                    <div
                      key={id}
                      className={`flex flex-col sm:flex-row sm:items-center justify-between p-3 rounded border gap-2 ${
                        isStudying ? 'border-purple-500 bg-purple-900/20' : 
                        milestoneInfo ? 'border-amber-500/50 bg-amber-900/10' :
                        'border-gray-700 bg-gray-800/30'
                      }`}
                    >
                      <div className="flex-1 min-w-0">
                        <div className="flex items-center gap-2 flex-wrap">
                          <span className="font-semibold text-sm">{skillDisplayName}</span>
                          {currentTier > 1 && (
                            <Badge className="bg-purple-600/50 text-purple-200 text-xs">Tier {currentTier} ({fmtDec(tierMultiplier, 0)}x)</Badge>
                          )}
                          {level > 0 && <span className="text-purple-400 text-sm">Lv.{level}</span>}
                          {selectedUpgrades.length > 0 && (
                            <div className="flex gap-1">
                              {selectedL5.length > 0 && (
                                <Badge className="bg-amber-700/50 text-amber-200 text-xs">L5: {selectedL5.length}</Badge>
                              )}
                              {selectedL10.length > 0 && (
                                <Badge className="bg-purple-700/50 text-purple-200 text-xs">L10: {selectedL10.length}</Badge>
                              )}
                            </div>
                          )}
                        </div>
                        <div className="text-xs text-gray-400 italic">{def.desc}{currentTier > 1 && ` (Tier ${currentTier}: ${fmtDec(tierMultiplier, 0)}x effect)`}</div>
                        {!prereqMet && def.req && (
                          <div className="text-xs text-red-400 mt-1">
                            Requires: {Object.entries(def.req).map(([r, rl]) => `${SKILLS_DEF[r]?.name} Lv.${rl}`).join(', ')}
                          </div>
                        )}
                        <div className="text-xs text-gray-500 mt-1">
                          <span className={effectiveSpeedMult > 1 ? 'text-green-400' : ''}>
                            Study: {formatStudyTime(effectiveStudyTime)}{effectiveSpeedMult > 1 && <span className="text-xs ml-1">({Math.round(effectiveSpeedMult * 100)}% speed)</span>}
                          </span>
                          {' • '}
                          <span className={costMult < 1 ? 'text-green-400' : ''}>
                            Cost: {fmt(cost)} mana{costMult < 1 && <span className="text-xs ml-1">({Math.round(costMult * 100)}% cost)</span>}
                          </span>
                        </div>
                        
                        {milestoneInfo && (
                          <div className="text-xs text-amber-400 mt-1 flex items-center gap-1">
                            ⭐ Level {milestoneInfo.milestone} milestone: {milestoneInfo.selectedCount}/2 upgrades selected
                          </div>
                        )}
                      </div>
                      
                      <div className="flex items-center gap-3 flex-wrap sm:flex-nowrap">
                        {/* Level dots */}
                        <div className="flex gap-1 shrink-0">
                          {Array.from({ length: def.max }).map((_, i) => (
                            <div
                              key={i}
                              className={`w-2 h-2 rounded-full border ${
                                i < level ? 'bg-purple-500 border-purple-400' : 
                                i === 4 || i === 9 ? 'border-amber-500' : 
                                'border-gray-600'
                              }`}
                            />
                          ))}
                        </div>
                        
                        {isStudying ? (
                          <div className="text-xs text-purple-400">
                            {formatStudyTime(store.currentStudyTarget?.progress || 0)}/{formatStudyTime(tierStudyTime)}
                          </div>
                        ) : milestoneInfo ? (
                          <Button
                            size="sm"
                            className="bg-amber-600 hover:bg-amber-700"
                            onClick={() => {
                              setUpgradeDialogSkill(tieredSkillId);
                              setUpgradeDialogMilestone(milestoneInfo.milestone);
                            }}
                          >
                            Choose Upgrades
                          </Button>
                        ) : canTierUp ? (
                          <Button
                            size="sm"
                            className="bg-purple-600 hover:bg-purple-700"
                            onClick={() => store.tierUpSkill(tieredSkillId)}
                          >
                            ⬆️ Tier Up
                          </Button>
                        ) : maxed ? (
                          <Badge className="bg-green-900/50 text-green-300">Maxed</Badge>
                        ) : (
                          <div className="flex gap-1">
                            <Button
                              size="sm"
                              variant={canStudy ? 'default' : 'outline'}
                              disabled={!canStudy}
                              className={canStudy ? 'bg-purple-600 hover:bg-purple-700' : 'opacity-50'}
                              onClick={() => store.startStudyingSkill(tieredSkillId)}
                            >
                              Study ({fmt(cost)})
                            </Button>
                            {/* Parallel Study button */}
                            {hasSpecial(upgradeEffects, SPECIAL_EFFECTS.PARALLEL_STUDY) && 
                             store.currentStudyTarget && 
                             !store.parallelStudyTarget &&
                             store.currentStudyTarget.id !== tieredSkillId &&
                             canStudy && (
                              <TooltipProvider>
                                <Tooltip>
                                  <TooltipTrigger asChild>
                                    <Button
                                      size="sm"
                                      variant="outline"
                                      className="border-cyan-500 text-cyan-400 hover:bg-cyan-900/30"
                                      onClick={() => store.startParallelStudySkill(tieredSkillId)}
                                    >
                                      ⚡
                                    </Button>
                                  </TooltipTrigger>
                                  <TooltipContent>
                                    <p>Study in parallel (50% speed)</p>
                                  </TooltipContent>
                                </Tooltip>
                              </TooltipProvider>
                            )}
                          </div>
                        )}
                      </div>
                    </div>
                  );
                })}
              </div>
            </CardContent>
            )}
          </Card>
        );
          });
      })()}
    </div>
  );
}