"""
流体动力学模块
负责实现流体的基本物理模拟和动力学计算
"""

import time
from typing import Dict, Any, List, Optional, Tuple
import math
import numpy as np

class FluidDynamics:
    """
    流体动力学模拟器
    负责实现流体的基本物理模拟和动力学计算
    """
    
    def __init__(self, plugin):
        """
        初始化流体动力学模拟器
        
        Args:
            plugin: 水体和流体模拟插件实例
        """
        self.plugin = plugin
        self.enabled = False
        self.initialized = False
        
        # 流体网格配置
        self.grid_config = {
            'resolution_x': 64,
            'resolution_y': 64,
            'resolution_z': 64,
            'cell_size': 1.0,           # 网格单元大小
            'boundary_condition': 'closed'  # 边界条件
        }
        
        # 物理参数
        self.physics_params = {
            'gravity': 9.81,            # 重力加速度 (m/s²)
            'viscosity': 0.001,         # 动力粘度 (Pa·s)
            'density': 1000.0,          # 密度 (kg/m³)
            'time_step': 0.016,         # 时间步长 (秒)
            'solver_iterations': 10     # 求解器迭代次数
        }
        
        # 流体状态场
        self.velocity_field = None      # 速度场
        self.pressure_field = None      # 压力场
        self.density_field = None       # 密度场
        self.temperature_field = None   # 温度场
        
        # 粒子系统
        self.fluid_particles = []
        self.particle_counter = 0
        self.max_particles = 10000
        
        # 边界条件
        self.boundary_conditions = {
            'left': 'closed',
            'right': 'closed',
            'top': 'closed',
            'bottom': 'closed',
            'front': 'closed',
            'back': 'closed'
        }
        
        # 外力影响
        self.external_forces = {
            'gravity': (0.0, -9.81, 0.0),
            'wind': (0.0, 0.0, 0.0),
            'buoyancy': (0.0, 0.0, 0.0)
        }
        
        # 模拟统计
        self.simulation_stats = {
            'steps_completed': 0,
            'particles_updated': 0,
            'solver_iterations': 0,
            'collision_count': 0
        }
        
        # 性能优化
        self.optimization_settings = {
            'adaptive_timestep': True,
            'spatial_partitioning': True,
            'particle_culling': True,
            'lod_simulation': True
        }
        
        print("✓ 流体动力学模拟器已创建")
        
    def initialize(self) -> bool:
        """
        初始化流体动力学模拟器
        
        Returns:
            是否初始化成功
        """
        try:
            # 初始化流体场
            self._initialize_fluid_fields()
            
            # 初始化粒子系统
            self._initialize_particle_system()
            
            self.initialized = True
            print("✓ 流体动力学模拟器初始化完成")
            return True
            
        except Exception as e:
            print(f"✗ 流体动力学模拟器初始化失败: {e}")
            import traceback
            traceback.print_exc()
            return False
            
    def enable(self) -> bool:
        """
        启用流体动力学模拟器
        
        Returns:
            是否启用成功
        """
        try:
            if not self.initialized:
                print("✗ 流体动力学模拟器未初始化")
                return False
                
            self.enabled = True
            print("✓ 流体动力学模拟器已启用")
            return True
            
        except Exception as e:
            print(f"✗ 流体动力学模拟器启用失败: {e}")
            import traceback
            traceback.print_exc()
            return False
            
    def disable(self):
        """禁用流体动力学模拟器"""
        try:
            self.enabled = False
            print("✓ 流体动力学模拟器已禁用")
            
        except Exception as e:
            print(f"✗ 流体动力学模拟器禁用失败: {e}")
            import traceback
            traceback.print_exc()
            
    def finalize(self):
        """清理流体动力学模拟器资源"""
        try:
            self.disable()
            self._clear_fluid_fields()
            self.fluid_particles.clear()
            self.initialized = False
            print("✓ 流体动力学模拟器资源已清理")
            
        except Exception as e:
            print(f"✗ 流体动力学模拟器资源清理失败: {e}")
            import traceback
            traceback.print_exc()
            
    def update(self, dt: float):
        """
        更新流体动力学模拟器状态
        
        Args:
            dt: 时间增量
        """
        try:
            if not self.enabled:
                return
                
            # 根据实际时间步长调整模拟步长
            actual_dt = dt * self.plugin.fluid_manager.simulation_config['simulation_speed']
            
            # 执行流体模拟步骤
            self._simulate_fluid_dynamics(actual_dt)
            
            # 更新统计信息
            self.simulation_stats['steps_completed'] += 1
            
        except Exception as e:
            print(f"✗ 流体动力学模拟器更新失败: {e}")
            import traceback
            traceback.print_exc()
            
    def _initialize_fluid_fields(self):
        """初始化流体场"""
        try:
            res_x = self.grid_config['resolution_x']
            res_y = self.grid_config['resolution_y']
            res_z = self.grid_config['resolution_z']
            
            # 初始化速度场 (每个维度一个分量)
            self.velocity_field = {
                'u': np.zeros((res_x, res_y, res_z)),  # x方向速度
                'v': np.zeros((res_x, res_y, res_z)),  # y方向速度
                'w': np.zeros((res_x, res_y, res_z))   # z方向速度
            }
            
            # 初始化压力场
            self.pressure_field = np.zeros((res_x, res_y, res_z))
            
            # 初始化密度场
            self.density_field = np.full((res_x, res_y, res_z), self.physics_params['density'])
            
            # 初始化温度场
            self.temperature_field = np.full((res_x, res_y, res_z), 20.0)  # 20°C
            
            print("✓ 流体场初始化完成")
            
        except Exception as e:
            print(f"✗ 流体场初始化失败: {e}")
            raise
            
    def _clear_fluid_fields(self):
        """清理流体场"""
        try:
            if self.velocity_field:
                for component in self.velocity_field.values():
                    component.fill(0)
                self.velocity_field = None
                
            if self.pressure_field is not None:
                self.pressure_field.fill(0)
                self.pressure_field = None
                
            if self.density_field is not None:
                self.density_field.fill(0)
                self.density_field = None
                
            if self.temperature_field is not None:
                self.temperature_field.fill(0)
                self.temperature_field = None
                
        except Exception as e:
            print(f"✗ 流体场清理失败: {e}")
            
    def _initialize_particle_system(self):
        """初始化粒子系统"""
        try:
            # 预分配粒子数组
            self.fluid_particles = []
            self.particle_counter = 0
            
            print("✓ 粒子系统初始化完成")
            
        except Exception as e:
            print(f"✗ 粒子系统初始化失败: {e}")
            raise
            
    def _simulate_fluid_dynamics(self, dt: float):
        """
        执行流体动力学模拟
        
        Args:
            dt: 时间步长
        """
        try:
            # 应用外力
            self._apply_external_forces(dt)
            
            # 更新速度场
            self._update_velocity_field(dt)
            
            # 求解压力场 (确保不可压缩性)
            self._solve_pressure_field()
            
            # 更新粒子
            self._update_fluid_particles(dt)
            
            # 处理边界条件
            self._apply_boundary_conditions()
            
        except Exception as e:
            print(f"✗ 流体动力学模拟失败: {e}")
            
    def _apply_external_forces(self, dt: float):
        """
        应用外力到流体
        
        Args:
            dt: 时间步长
        """
        try:
            if not self.velocity_field:
                return
                
            res_x, res_y, res_z = self.velocity_field['u'].shape
            
            # 应用重力
            gravity = self.external_forces['gravity']
            self.velocity_field['v'] += gravity[1] * dt
            
            # 应用风力
            wind = self.external_forces['wind']
            self.velocity_field['u'] += wind[0] * dt
            self.velocity_field['w'] += wind[2] * dt
            
            # 应用浮力 (基于温度和密度差异)
            buoyancy = self.external_forces['buoyancy']
            self.velocity_field['v'] += buoyancy[1] * dt
            
        except Exception as e:
            print(f"✗ 外力应用失败: {e}")
            
    def _update_velocity_field(self, dt: float):
        """
        更新速度场
        
        Args:
            dt: 时间步长
        """
        try:
            if not self.velocity_field:
                return
                
            # 添加粘性扩散项
            self._apply_viscosity(dt)
            
            # 添加对流项
            self._apply_advection(dt)
            
        except Exception as e:
            print(f"✗ 速度场更新失败: {e}")
            
    def _apply_viscosity(self, dt: float):
        """
        应用粘性扩散
        
        Args:
            dt: 时间步长
        """
        try:
            if not self.velocity_field:
                return
                
            viscosity = self.physics_params['viscosity']
            cell_size = self.grid_config['cell_size']
            
            # 简化的粘性扩散计算 (拉普拉斯算子)
            # 在实际实现中，这会是一个更复杂的计算
            pass  # 简化处理，实际实现中会计算粘性扩散
            
        except Exception as e:
            print(f"✗ 粘性扩散应用失败: {e}")
            
    def _apply_advection(self, dt: float):
        """
        应用对流项
        
        Args:
            dt: 时间步长
        """
        try:
            if not self.velocity_field:
                return
                
            # 简化的对流计算
            # 在实际实现中，这会使用半拉格朗日方法追踪粒子轨迹
            pass  # 简化处理，实际实现中会计算对流
            
        except Exception as e:
            print(f"✗ 对流项应用失败: {e}")
            
    def _solve_pressure_field(self):
        """求解压力场"""
        try:
            # 使用投影方法确保不可压缩性
            # 在实际实现中，这会使用泊松方程求解器
            self.simulation_stats['solver_iterations'] += self.physics_params['solver_iterations']
            
        except Exception as e:
            print(f"✗ 压力场求解失败: {e}")
            
    def _update_fluid_particles(self, dt: float):
        """
        更新流体粒子
        
        Args:
            dt: 时间步长
        """
        try:
            updated_count = 0
            for particle in self.fluid_particles:
                if particle['active']:
                    # 更新粒子位置
                    velocity = particle['velocity']
                    particle['position'] = (
                        particle['position'][0] + velocity[0] * dt,
                        particle['position'][1] + velocity[1] * dt,
                        particle['position'][2] + velocity[2] * dt
                    )
                    
                    # 应用重力
                    particle['velocity'] = (
                        velocity[0],
                        velocity[1] - self.physics_params['gravity'] * dt,
                        velocity[2]
                    )
                    
                    updated_count += 1
                    
            self.simulation_stats['particles_updated'] += updated_count
            
        except Exception as e:
            print(f"✗ 流体粒子更新失败: {e}")
            
    def _apply_boundary_conditions(self):
        """应用边界条件"""
        try:
            # 根据边界条件设置边界值
            # 在实际实现中，这会处理各种边界条件
            pass
            
        except Exception as e:
            print(f"✗ 边界条件应用失败: {e}")
            
    def add_fluid_particle(self, position: Tuple[float, float, float], 
                          velocity: Tuple[float, float, float] = (0.0, 0.0, 0.0),
                          density: float = None) -> int:
        """
        添加流体粒子
        
        Args:
            position: 粒子位置 (x, y, z)
            velocity: 粒子速度 (vx, vy, vz)
            density: 粒子密度
            
        Returns:
            粒子ID
        """
        try:
            if len(self.fluid_particles) >= self.max_particles:
                print("✗ 粒子数量已达上限")
                return -1
                
            if density is None:
                density = self.physics_params['density']
                
            particle_id = self.particle_counter
            self.particle_counter += 1
            
            particle = {
                'id': particle_id,
                'position': position,
                'velocity': velocity,
                'density': density,
                'temperature': 20.0,
                'active': True,
                'creation_time': time.time()
            }
            
            self.fluid_particles.append(particle)
            
            return particle_id
            
        except Exception as e:
            print(f"✗ 流体粒子添加失败: {e}")
            return -1
            
    def remove_fluid_particle(self, particle_id: int) -> bool:
        """
        移除流体粒子
        
        Args:
            particle_id: 粒子ID
            
        Returns:
            是否移除成功
        """
        try:
            for i, particle in enumerate(self.fluid_particles):
                if particle['id'] == particle_id:
                    self.fluid_particles.pop(i)
                    return True
                    
            print(f"✗ 粒子不存在: {particle_id}")
            return False
            
        except Exception as e:
            print(f"✗ 流体粒子移除失败: {e}")
            return False
            
    def get_fluid_particle(self, particle_id: int) -> Optional[Dict[str, Any]]:
        """
        获取流体粒子信息
        
        Args:
            particle_id: 粒子ID
            
        Returns:
            粒子信息或None
        """
        try:
            for particle in self.fluid_particles:
                if particle['id'] == particle_id:
                    return particle.copy()
            return None
            
        except Exception as e:
            print(f"✗ 流体粒子获取失败: {e}")
            return None
            
    def set_external_force(self, force_name: str, force_vector: Tuple[float, float, float]):
        """
        设置外力
        
        Args:
            force_name: 力的名称
            force_vector: 力向量 (fx, fy, fz)
        """
        try:
            if force_name in self.external_forces:
                self.external_forces[force_name] = force_vector
                print(f"✓ 外力 '{force_name}' 已设置: {force_vector}")
            else:
                print(f"✗ 无效的外力名称: {force_name}")
                
        except Exception as e:
            print(f"✗ 外力设置失败: {e}")
            
    def get_external_forces(self) -> Dict[str, Tuple[float, float, float]]:
        """
        获取所有外力
        
        Returns:
            外力字典
        """
        return self.external_forces.copy()
        
    def set_physics_parameters(self, params: Dict[str, float]):
        """
        设置物理参数
        
        Args:
            params: 物理参数字典
        """
        try:
            self.physics_params.update(params)
            print(f"✓ 物理参数已更新: {self.physics_params}")
        except Exception as e:
            print(f"✗ 物理参数设置失败: {e}")
            
    def get_physics_parameters(self) -> Dict[str, float]:
        """
        获取物理参数
        
        Returns:
            物理参数字典
        """
        return self.physics_params.copy()
        
    def set_grid_configuration(self, config: Dict[str, Any]):
        """
        设置网格配置
        
        Args:
            config: 网格配置字典
        """
        try:
            old_resolution = (
                self.grid_config['resolution_x'],
                self.grid_config['resolution_y'],
                self.grid_config['resolution_z']
            )
            
            self.grid_config.update(config)
            
            new_resolution = (
                self.grid_config['resolution_x'],
                self.grid_config['resolution_y'],
                self.grid_config['resolution_z']
            )
            
            # 如果分辨率改变，重新初始化流体场
            if old_resolution != new_resolution:
                self._initialize_fluid_fields()
                
            print(f"✓ 网格配置已更新: {self.grid_config}")
        except Exception as e:
            print(f"✗ 网格配置设置失败: {e}")
            
    def get_grid_configuration(self) -> Dict[str, Any]:
        """
        获取网格配置
        
        Returns:
            网格配置字典
        """
        return self.grid_config.copy()
        
    def get_simulation_stats(self) -> Dict[str, int]:
        """
        获取模拟统计信息
        
        Returns:
            统计信息字典
        """
        return self.simulation_stats.copy()
        
    def reset_simulation_stats(self):
        """重置模拟统计信息"""
        try:
            self.simulation_stats = {
                'steps_completed': 0,
                'particles_updated': 0,
                'solver_iterations': 0,
                'collision_count': 0
            }
            print("✓ 模拟统计信息已重置")
        except Exception as e:
            print(f"✗ 模拟统计信息重置失败: {e}")
            
    def get_fluid_velocity_at(self, x: int, y: int, z: int) -> Optional[Tuple[float, float, float]]:
        """
        获取指定位置的流体速度
        
        Args:
            x, y, z: 网格坐标
            
        Returns:
            速度向量 (vx, vy, vz) 或 None
        """
        try:
            if not self.velocity_field:
                return None
                
            shape = self.velocity_field['u'].shape
            if 0 <= x < shape[0] and 0 <= y < shape[1] and 0 <= z < shape[2]:
                vx = self.velocity_field['u'][x, y, z]
                vy = self.velocity_field['v'][x, y, z]
                vz = self.velocity_field['w'][x, y, z]
                return (float(vx), float(vy), float(vz))
                
            return None
            
        except Exception as e:
            print(f"✗ 速度获取失败: {e}")
            return None
            
    def set_fluid_velocity_at(self, x: int, y: int, z: int, velocity: Tuple[float, float, float]):
        """
        设置指定位置的流体速度
        
        Args:
            x, y, z: 网格坐标
            velocity: 速度向量 (vx, vy, vz)
        """
        try:
            if not self.velocity_field:
                return
                
            shape = self.velocity_field['u'].shape
            if 0 <= x < shape[0] and 0 <= y < shape[1] and 0 <= z < shape[2]:
                self.velocity_field['u'][x, y, z] = velocity[0]
                self.velocity_field['v'][x, y, z] = velocity[1]
                self.velocity_field['w'][x, y, z] = velocity[2]
                
        except Exception as e:
            print(f"✗ 速度设置失败: {e}")
            
    def calculate_cfl_condition(self) -> float:
        """
        计算CFL条件(柯朗-弗里德里希-李维条件)
        
        Returns:
            CFL数
        """
        try:
            if not self.velocity_field:
                return 0.0
                
            max_velocity = 0.0
            # 计算最大速度
            u_max = np.max(np.abs(self.velocity_field['u']))
            v_max = np.max(np.abs(self.velocity_field['v']))
            w_max = np.max(np.abs(self.velocity_field['w']))
            max_velocity = max(u_max, v_max, w_max)
            
            cell_size = self.grid_config['cell_size']
            dt = self.physics_params['time_step']
            
            # CFL = (v * dt) / dx
            cfl = (max_velocity * dt) / cell_size if cell_size > 0 else 0.0
            return cfl
            
        except Exception as e:
            print(f"✗ CFL条件计算失败: {e}")
            return 0.0
            
    def is_stable(self) -> bool:
        """
        检查模拟是否稳定
        
        Returns:
            是否稳定
        """
        try:
            # CFL条件应小于等于1以保证稳定性
            cfl = self.calculate_cfl_condition()
            return cfl <= 1.0
            
        except Exception as e:
            print(f"✗ 稳定性检查失败: {e}")
            return False