import { Injectable } from '@angular/core';
import { BehaviorSubject } from 'rxjs';
import { SharedStateService } from '../../service/shared-state.service';

export interface SelectionData {
  label: string;
  numbers: (number | string)[];
  value: number;
  total: number;
  isBoxed?: boolean;
}

@Injectable({ providedIn: 'root' })
export class SelectionService {
  private selections = new BehaviorSubject<SelectionData[]>([]);
  selections$ = this.selections.asObservable();

  private currentRow = new BehaviorSubject<SelectionData>({
    label: '',
    numbers: [],
    value: 0,
    total: 0,
    isBoxed: false
  });
  currentRow$ = this.currentRow.asObservable();

  private runnerCount: number = 12; // Fallback

  constructor(private sharedStateService: SharedStateService) {
    this.sharedStateService.runnerCount$.subscribe(count => {
      this.runnerCount = count || 12; // Update runner count dynamically
    });
  }

  updatePartial(update: Partial<SelectionData>) {
    const current = this.currentRow.value;
    const updated: SelectionData = { ...current, ...update };

    const label = updated.label;
    const value = updated.value;
    const numbers = updated.numbers || [];
    const isBoxed = updated.isBoxed ?? false;

    // Enforce ticket number limit (1-100)
    if (value > 100) {
      updated.value = 100;
    }

    updated.total = 0;

    if ((numbers.length > 0 || numbers.includes('F')) && value > 0 && label) {
      switch (label) {
        case 'WIN':
        case 'SHP':
        case 'THP':
        case 'PLC':
        case 'SHW':
        case 'WSP': {
          if (numbers.includes('F')) {
            updated.total = this.runnerCount * value * 10;
          } else {
            updated.total = numbers.filter(n => typeof n === 'number').length * value * 10;
          }
          break;
        }

        case 'FOR':
        case 'EXA': {
          const dashIndex = numbers.indexOf('-');
          const group1 = dashIndex === -1 ? numbers : numbers.slice(0, dashIndex);
          const group2 = dashIndex === -1 ? [] : numbers.slice(dashIndex + 1);
          const group1Count = group1.includes('F') ? this.runnerCount : group1.filter(n => typeof n === 'number').length;
          const group2Count = group2.includes('F') ? this.runnerCount : group2.filter(n => typeof n === 'number').length;

          let combinations = 0;

          if (isBoxed) {
            const allNums = [...group1, ...group2].filter(n => typeof n === 'number') as number[];
            const uniqueCount = group1.includes('F') || group2.includes('F') ? this.runnerCount : new Set(allNums).size;
            combinations = uniqueCount >= 2 ? this.calculatePermutations(uniqueCount) : 0;
            updated.numbers = [...group1, ...(group2.length ? ['-', ...group2] : [])];
          } else {
            combinations = group1Count * group2Count;
            updated.numbers = [...group1, ...(group2.length ? ['-', ...group2] : [])];
          }

          updated.total = combinations * value * 10;
          break;
        }

        case 'QUI': {
          const dashIndex = numbers.indexOf('-');
          const group1 = dashIndex === -1 ? numbers : numbers.slice(0, dashIndex);
          const group2 = dashIndex === -1 ? [] : numbers.slice(dashIndex + 1);
          const group1Count = group1.includes('F') ? this.runnerCount : group1.filter(n => typeof n === 'number').length;
          const group2Count = group2.includes('F') ? this.runnerCount : group2.filter(n => typeof n === 'number').length;

          let combinations = 0;

          if (isBoxed) {
            const allNums = [...group1, ...group2].filter(n => typeof n === 'number') as number[];
            const uniqueCount = group1.includes('F') || group2.includes('F') ? this.runnerCount : new Set(allNums).size;
            combinations = uniqueCount >= 2 ? this.calculateCombinations(uniqueCount) : 0;
            updated.numbers = [...group1, ...(group2.length ? ['-', ...group2] : [])];
          } else {
            combinations = (group1Count * group2Count) ;
            updated.numbers = [...group1, ...(group2.length ? ['-', ...group2] : [])];
          }

          updated.total = combinations * value * 10;
          break;
        }

        case 'TAN': {
          const dashIndices = numbers
            .map((n, idx) => (n === '-' ? idx : -1))
            .filter(idx => idx !== -1);

          if (dashIndices.length < 2 && !isBoxed) break;

          const group1 = dashIndices.length > 0 ? numbers.slice(0, dashIndices[0]) : numbers;
          const group2 = dashIndices.length > 0 ? numbers.slice(dashIndices[0] + 1, dashIndices[1] || numbers.length) : [];
          const group3 = dashIndices.length > 1 ? numbers.slice(dashIndices[1] + 1) : [];

          let combinations = 0;

          if (isBoxed) {
            if (numbers.includes('F')) {
              combinations = this.calculatePermutationsN(this.runnerCount, 3);
            } else {
              const allNums = [...group1, ...group2, ...group3].filter(n => typeof n === 'number') as number[];
              combinations = allNums.length >= 3 ? this.calculatePermutationsN(allNums.length, 3) : 0;
            }
          } else {
            const group1Count = group1.includes('F') ? this.runnerCount : group1.filter(n => typeof n === 'number').length;
            const group2Count = group2.includes('F') ? this.runnerCount : group2.filter(n => typeof n === 'number').length;
            const group3Count = group3.includes('F') ? this.runnerCount : group3.filter(n => typeof n === 'number').length;
            combinations = group1Count * group2Count * group3Count;
          }

          updated.numbers = [...group1, ...(group2.length ? ['-', ...group2] : []), ...(group3.length ? ['-', ...group3] : [])];
          updated.total = combinations * value * 10;
          break;
        }

        case 'TRE':
        case 'MJP':
        case 'JKP': {
          const legs = this.splitToLegs(numbers, this.getLegCount(label));
          const requiredLegs = this.getLegCount(label);

          const legCounts = legs.map(leg => leg.includes('F') ? this.runnerCount : leg.filter(n => typeof n === 'number').length);
          const filledLegs = legs.filter(leg => leg.length > 0).length;

          if (filledLegs >= requiredLegs - 1) {
            const combinations = legCounts.reduce((acc, count) => acc * (count || 1), 1);
            updated.total = combinations * value * 10;
          }
          break;
        }

        // ⚪ BOX logic
        default: {
          const combCount = isBoxed
            ? this.calculatePermutations(numbers.filter(n => typeof n === 'number').length)
            : this.calculateCombinations(numbers.filter(n => typeof n === 'number').length);
          updated.total = combCount * value * 10;
          break;
        }
      }
    }

    this.currentRow.next(updated);
  }

  finalizeCurrentRow() {
    const completed = this.currentRow.value;
    if (!completed.label || completed.numbers.length === 0 || completed.value <= 0) return;
    const currentSelections = this.selections.value;
    const totalAmount = currentSelections.reduce((sum, sel) => sum + sel.total, 0);
    if (totalAmount + completed.total > 5000) return;
    this.selections.next([...currentSelections, { ...completed }]);
    this.currentRow.next({ label: '', numbers: [], value: 0, total: 0, isBoxed: false });
  }

  clearSelections() {
    this.selections.next([]);
    this.currentRow.next({ label: '', numbers: [], value: 0, total: 0, isBoxed: false });
  }

  private calculateCombinations(n: number): number {
    return n >= 2 ? (n * (n - 1)) / 2 : 0;
  }

  private calculatePermutations(n: number): number {
    return n >= 2 ? n * (n - 1) : 0;
  }

  private calculatePermutationsN(n: number, r: number): number {
    if (n < r) return 0;
    let result = 1;
    for (let i = 0; i < r; i++) {
      result *= (n - i);
    }
    return result;
  }

  private splitToLegs(numbers: (number | string)[], legCount: number): (number | string)[][] {
    const result: (number | string)[][] = [];
    let currentLeg: (number | string)[] = [];
    let separatorCount = 0;

    for (const item of numbers) {
      if (item === '/') {
        if (currentLeg.length > 0) {
          result.push([...currentLeg]);
          currentLeg = [];
          separatorCount++;
        }
        if (separatorCount >= legCount - 1) break;
      } else {
        currentLeg.push(item);
      }
    }

    // Push the last leg if it has numbers
    if (currentLeg.length > 0) {
      result.push([...currentLeg]);
    }

    // Fill remaining legs with empty arrays if needed
    while (result.length < legCount) {
      result.push([]);
    }

    return result.slice(0, legCount);
  }

  private getLegCount(label: string): number {
    switch (label) {
      case 'TRE': return 3;
      case 'MJP': return 4;
      case 'JKP': return 5;
      default: return 3;
    }
  }
}