import numpy as np
import pyswarms as ps


def cargo_load_planning_pso_v2(weights, cargo_names, cargo_types_dict, positions, cg_impact, cg_impact_2u, cg_impact_4u,
                               max_positions, options=None, swarmsize=100, maxiter=100):
    """
    使用二进制粒子群优化方法计算货物装载方案，最小化重心的变化量。

    参数:
        weights (list): 每个货物的质量列表。
        cargo_names (list): 每个货物的名称。
        cargo_types_dict (dict): 货物名称和占用的货位数量。
        positions (list): 可用的货位编号。
        cg_impact (list): 每个位置每kg货物对重心index的影响系数。
        cg_impact_2u (list): 两个位置组合的重心影响系数。
        cg_impact_4u (list): 四个位置组合的重心影响系数。
        max_positions (int): 总货位的数量。
        options (dict, optional): PSO算法的配置选项。
        swarmsize (int, optional): 粒子群大小。
        maxiter (int, optional): 最大迭代次数。

    返回:
        best_solution (np.array): 最优装载方案矩阵。
        best_cg_change (float): 最优方案的重心变化量。
    """
    # 将货物类型映射为对应的占用单位数
    cargo_types = [cargo_types_dict[name] for name in cargo_names]

    num_cargos = len(weights)  # 货物数量
    num_positions = len(positions)  # 可用货位数量
    dimension = num_cargos * max_positions  # 每个粒子的维度：货物数量 × 可用货位数量

    # 如果未提供options，使用默认配置
    if options is None:
        options = {'c1': 0.5, 'c2': 0.3, 'w': 0.9}

    # 定义适应度评估函数
    def fitness_function(x):
        """
        计算每个粒子的适应度值。

        参数:
            x (numpy.ndarray): 粒子的位置数组，形状为 (n_particles, dimension)。

        返回:
            numpy.ndarray: 每个粒子的适应度值。
        """
        fitness = np.zeros(x.shape[0])

        for idx, particle in enumerate(x):
            # 将连续位置映射为离散起始位置
            start_positions = []
            penalty = 0
            cg_change = 0.0
            occupied = np.zeros(num_positions, dtype=int)

            for i in range(num_cargos):
                cargo_type = cargo_types[i]
                pos_continuous = particle[i * max_positions:(i + 1) * max_positions]

                # 根据粒子位置值选择最佳货位
                start_pos = np.argmax(pos_continuous)

                # 检查边界
                if start_pos < 0 or start_pos + cargo_type > num_positions:
                    penalty += 1000
                    continue

                # 检查对齐
                if cargo_type == 2 and start_pos % 2 != 0:
                    penalty += 1000
                if cargo_type == 4 and start_pos % 4 != 0:
                    penalty += 1000

                # 检查重叠
                if np.any(occupied[start_pos:start_pos + cargo_type]):
                    penalty += 1000
                else:
                    occupied[start_pos:start_pos + cargo_type] = 1

                start_positions.append(start_pos)

                # 计算重心变化量
                if cargo_type == 1:
                    cg_change += weights[i] * cg_impact[start_pos]
                elif cargo_type == 2:
                    cg_change += weights[i] * cg_impact_2u[start_pos // 2]
                elif cargo_type == 4:
                    cg_change += weights[i] * cg_impact_4u[start_pos // 4]

            fitness[idx] = cg_change + penalty

        return fitness

    # 设置PSO的边界
    # 对于每个货物，起始位置的范围根据货物类型对齐
    lower_bounds = []
    upper_bounds = []
    for i in range(num_cargos):
        cargo_type = cargo_types[i]
        lower_bounds.append([0] * max_positions)
        upper_bounds.append([1] * max_positions)

    bounds = (np.array(lower_bounds), np.array(upper_bounds))

    # 初始化PSO优化器
    optimizer = ps.single.GlobalBestPSO(n_particles=swarmsize, dimensions=dimension, options=options, bounds=bounds)

    # 运行PSO优化
    best_cost, best_pos = optimizer.optimize(fitness_function, iters=maxiter)

    # 将最佳位置映射为离散装载方案
    best_start_positions = []
    penalty = 0
    cg_change = 0.0
    occupied = np.zeros(num_positions, dtype=int)

    for i in range(num_cargos):
        cargo_type = cargo_types[i]
        pos_continuous = best_pos[i * max_positions:(i + 1) * max_positions]

        # 根据粒子位置值选择最佳货位
        start_pos = np.argmax(pos_continuous)

        # 检查边界
        if start_pos < 0 or start_pos + cargo_type > num_positions:
            penalty += 1000
            best_start_positions.append(start_pos)
            continue

        # 检查对齐
        if cargo_type == 2 and start_pos % 2 != 0:
            penalty += 1000
        if cargo_type == 4 and start_pos % 4 != 0:
            penalty += 1000

        # 检查重叠
        if np.any(occupied[start_pos:start_pos + cargo_type]):
            penalty += 1000
        else:
            occupied[start_pos:start_pos + cargo_type] = 1

        best_start_positions.append(start_pos)

        # 计算重心变化量
        if cargo_type == 1:
            cg_change += abs(weights[i] * cg_impact[start_pos])
        elif cargo_type == 2:
            cg_change += abs(weights[i] * cg_impact_2u[start_pos // 2])
        elif cargo_type == 4:
            cg_change += abs(weights[i] * cg_impact_4u[start_pos // 4])

    total_cg_change = cg_change + penalty

    # 构建装载方案矩阵
    best_xij = np.zeros((num_cargos, num_positions), dtype=int)
    for i, start_pos in enumerate(best_start_positions):
        cargo_type = cargo_types[i]
        for k in range(cargo_type):
            pos = start_pos + k
            if pos < num_positions:
                best_xij[i, pos] = 1

    # 检查是否有严重惩罚，判断是否找到可行解
    if total_cg_change >= -999999:
        return best_xij, total_cg_change
    else:
        return [], -1000000


# 示例调用