/**
 * Hexagonal grid map for the DiceWars game.
 * 
 * Map is a 20x20 hexagonal grid where each cell can be:
 * - passable (playable)
 * - impassable (blocked)
 * 
 * Uses axial coordinates (q, r) for hexagon positioning.
 */

const MAP_SIZE = 20;
const CELL_TYPES = {
  EMPTY: 0,      // Passable, unowned
  BLOCKED: 1,    // Impassable terrain
  PLAYER1: 2,    // Player 1 owned
  PLAYER2: 3,    // Player 2 owned
};

/**
 * Represents a single hex cell on the map
 */
class HexCell {
  constructor(q, r, type = CELL_TYPES.EMPTY) {
    this.q = q;           // Axial coordinate q
    this.r = r;           // Axial coordinate r
    this.type = type;     // Cell ownership/type
    this.dice = [];       // Array of dice values on this cell
  }

  /**
   * Calculate unit strength: F = (cnt-1)*full_dice + current_dice
   */
  getStrength() {
    if (this.dice.length === 0) return 0;
    const cnt = this.dice.length;
    const fullDice = 6;
    const currentDice = this.dice[this.dice.length - 1]; // Top die
    return (cnt - 1) * fullDice + currentDice;
  }

  /**
   * Check if cell has maximum strength (8 dice with 6 on top)
   */
  isMaxStrength() {
    return this.dice.length >= 8 && this.getStrength() >= 48;
  }

  /**
   * Add a die to this cell
   */
  addDie(value) {
    if (this.dice.length < 8) {
      this.dice.push(value);
      return true;
    }
    return false;
  }

  /**
   * Remove dice from cell, leaving specified strength
   */
  setStrength(targetStrength) {
    if (targetStrength <= 0) {
      this.dice = [];
      return;
    }
    
    const fullDice = 6;
    const cnt = Math.floor((targetStrength - 1) / fullDice) + 1;
    const remainder = targetStrength - (cnt - 1) * fullDice;
    
    this.dice = new Array(cnt - 1).fill(6);
    if (remainder > 0) {
      this.dice.push(remainder);
    }
  }

  isPassable() {
    return this.type !== CELL_TYPES.BLOCKED;
  }

  isOwned() {
    return this.type === CELL_TYPES.PLAYER1 || this.type === CELL_TYPES.PLAYER2;
  }

  getOwner() {
    if (this.type === CELL_TYPES.PLAYER1) return 1;
    if (this.type === CELL_TYPES.PLAYER2) return 2;
    return 0;
  }
}

/**
 * Hexagonal map generator and manager
 */
class HexMap {
  constructor(size = MAP_SIZE) {
    this.size = size;
    this.cells = new Map(); // Key: "q,r", Value: HexCell
    this.generate();
  }

  /**
   * Generate the hexagonal grid
   */
  generate() {
    this.cells.clear();
    
    for (let q = 0; q < this.size; q++) {
      for (let r = 0; r < this.size; r++) {
        const key = this.getKey(q, r);
        const type = Math.random() < 0.15 ? CELL_TYPES.BLOCKED : CELL_TYPES.EMPTY;
        this.cells.set(key, new HexCell(q, r, type));
      }
    }
  }

  /**
   * Get cell by axial coordinates
   */
  getCell(q, r) {
    const key = this.getKey(q, r);
    return this.cells.get(key);
  }

  /**
   * Get cell by key string
   */
  getCellByKey(key) {
    return this.cells.get(key);
  }

  /**
   * Generate key from coordinates
   */
  getKey(q, r) {
    return `${q},${r}`;
  }

  /**
   * Get all passable cells
   */
  getPassableCells() {
    return Array.from(this.cells.values()).filter(cell => cell.isPassable());
  }

  /**
   * Get all empty (unowned) passable cells
   */
  getEmptyCells() {
    return Array.from(this.cells.values()).filter(
      cell => cell.isPassable() && !cell.isOwned()
    );
  }

  /**
   * Get all cells owned by a player
   */
  getPlayerCells(playerId) {
    const targetType = playerId === 1 ? CELL_TYPES.PLAYER1 : CELL_TYPES.PLAYER2;
    return Array.from(this.cells.values()).filter(
      cell => cell.type === targetType
    );
  }

  /**
   * Get neighboring cells (6 directions in hex grid)
   */
  getNeighbors(q, r) {
    const directions = [
      [1, 0], [1, -1], [0, -1],
      [-1, 0], [-1, 1], [0, 1]
    ];
    
    const neighbors = [];
    for (const [dq, dr] of directions) {
      const nq = q + dq;
      const nr = r + dr;
      if (nq >= 0 && nq < this.size && nr >= 0 && nr < this.size) {
        const cell = this.getCell(nq, nr);
        if (cell && cell.isPassable()) {
          neighbors.push(cell);
        }
      }
    }
    return neighbors;
  }

  /**
   * Calculate supply for a player: S = size of largest solid (connected) territory
   * A solid territory is a connected region of player's cells
   */
  calculateSupply(playerId) {
    const playerCells = this.getPlayerCells(playerId);
    if (playerCells.length === 0) return 0;

    // Build adjacency map for player cells
    const cellMap = new Map();
    for (const cell of playerCells) {
      cellMap.set(this.getKey(cell.q, cell.r), cell);
    }

    // Find connected components using BFS
    const visited = new Set();
    let maxTerritory = 0;

    for (const cell of playerCells) {
      const key = this.getKey(cell.q, cell.r);
      if (visited.has(key)) continue;

      // BFS to find size of this territory
      let territorySize = 0;
      const queue = [cell];
      visited.add(key);

      while (queue.length > 0) {
        const current = queue.shift();
        territorySize++;

        // Get all neighbors that are also player cells
        const neighbors = this.getNeighbors(current.q, current.r);
        for (const neighbor of neighbors) {
          if (neighbor.getOwner() === playerId) {
            const nKey = this.getKey(neighbor.q, neighbor.r);
            if (!visited.has(nKey)) {
              visited.add(nKey);
              queue.push(neighbor);
            }
          }
        }
      }

      maxTerritory = Math.max(maxTerritory, territorySize);
    }

    return maxTerritory;
  }

  /**
   * Render map to console (simplified ASCII representation)
   */
  render() {
    let output = '';
    
    for (let r = 0; r < this.size; r++) {
      // Offset every other row for hex appearance
      const offset = r % 2 === 0 ? 0 : 2;
      output += ' '.repeat(offset);
      
      for (let q = 0; q < this.size; q++) {
        const cell = this.getCell(q, r);
        const symbol = this.getCellSymbol(cell);
        output += `[${symbol}]`;
      }
      output += '\n';
    }
    
    console.log(output);
  }

  /**
   * Get symbol for cell visualization
   */
  getCellSymbol(cell) {
    if (cell.type === CELL_TYPES.BLOCKED) return '██';
    if (cell.type === CELL_TYPES.PLAYER1) return 'P1';
    if (cell.type === CELL_TYPES.PLAYER2) return 'P2';
    if (cell.dice.length > 0) return cell.getStrength().toString().padStart(2, ' ');
    return '  ';
  }

  /**
   * Set cell ownership
   */
  setOwner(q, r, playerId) {
    const cell = this.getCell(q, r);
    if (cell && cell.isPassable()) {
      cell.type = playerId === 1 ? CELL_TYPES.PLAYER1 : CELL_TYPES.PLAYER2;
      return true;
    }
    return false;
  }

  /**
   * Clear cell ownership
   */
  clearOwner(q, r) {
    const cell = this.getCell(q, r);
    if (cell) {
      cell.type = CELL_TYPES.EMPTY;
      cell.dice = [];
      return true;
    }
    return false;
  }
}

// ES Module exports for browser
export { HexMap, HexCell, CELL_TYPES, MAP_SIZE };

// CommonJS exports for Node.js
if (typeof module !== 'undefined' && module.exports) {
  module.exports = { HexMap, HexCell, CELL_TYPES, MAP_SIZE };
}