package com.gym.service;

import com.gym.model.TrainingPlan;
import com.gym.model.User;
import com.gym.repository.TrainingPlanRepository;
import com.gym.repository.UserRepository;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import java.time.LocalDate;
import java.time.LocalDateTime;
import java.time.temporal.ChronoUnit;
import java.util.List;
import java.util.Optional;

// 需要导入的包
import java.util.HashMap;
import java.util.Map;
import java.util.stream.Collectors;

@Service
public class TrainingPlanService {

    @Autowired
    private TrainingPlanRepository trainingPlanRepository;

    @Autowired
    private UserRepository userRepository;

    // 创建训练计划
    public TrainingPlan createPlan(TrainingPlan plan, Long memberId, Long coachId) {
        // 验证会员是否存在
        User member = userRepository.findById(memberId)
                .orElseThrow(() -> new RuntimeException("会员不存在"));

        // 验证教练是否存在
        User coach = userRepository.findById(coachId)
                .orElseThrow(() -> new RuntimeException("教练不存在"));

        // 验证角色
        if (!"MEMBER".equals(member.getRole())) {
            throw new RuntimeException("该用户不是会员");
        }
        if (!"COACH".equals(coach.getRole())) {
            throw new RuntimeException("该用户不是教练");
        }

        plan.setMember(member);
        plan.setCoach(coach);
        plan.setCompletedDays(0);
        plan.setProgress(0.0);
        plan.setStatus("ACTIVE");
        plan.setCreateTime(LocalDateTime.now());
        plan.setUpdateTime(LocalDateTime.now());

        // 如果提供了开始和结束日期，计算周期
        if (plan.getStartDate() != null && plan.getEndDate() != null) {
            long days = ChronoUnit.DAYS.between(plan.getStartDate(), plan.getEndDate());
            plan.setDurationWeeks((int) (days / 7));
        }

        return trainingPlanRepository.save(plan);
    }

    // 获取所有训练计划
    public List<TrainingPlan> getAllPlans() {
        return trainingPlanRepository.findAll();
    }

    // 根据ID获取训练计划
    public Optional<TrainingPlan> getPlanById(Long id) {
        return trainingPlanRepository.findById(id);
    }

    // 获取会员的训练计划
    public List<TrainingPlan> getMemberPlans(Long memberId) {
        return trainingPlanRepository.findByMemberId(memberId);
    }

    // 获取教练制定的训练计划
    public List<TrainingPlan> getCoachPlans(Long coachId) {
        return trainingPlanRepository.findByCoachId(coachId);
    }

    // 获取活跃的训练计划
    public List<TrainingPlan> getActivePlansByMember(Long memberId) {
        return trainingPlanRepository.findActivePlansByMember(memberId);
    }

    // 更新训练计划
    public TrainingPlan updatePlan(Long id, TrainingPlan updatedPlan) {
        return trainingPlanRepository.findById(id)
                .map(plan -> {
                    if (updatedPlan.getGoal() != null) {
                        plan.setGoal(updatedPlan.getGoal());
                    }
                    if (updatedPlan.getDailyPlan() != null) {
                        plan.setDailyPlan(updatedPlan.getDailyPlan());
                    }
                    if (updatedPlan.getDietAdvice() != null) {
                        plan.setDietAdvice(updatedPlan.getDietAdvice());
                    }
                    if (updatedPlan.getTrainingContent() != null) {
                        plan.setTrainingContent(updatedPlan.getTrainingContent());
                    }
                    if (updatedPlan.getRestDays() != null) {
                        plan.setRestDays(updatedPlan.getRestDays());
                    }
                    if (updatedPlan.getDifficultyLevel() != null) {
                        plan.setDifficultyLevel(updatedPlan.getDifficultyLevel());
                    }
                    if (updatedPlan.getWarmupSuggestions() != null) {
                        plan.setWarmupSuggestions(updatedPlan.getWarmupSuggestions());
                    }
                    if (updatedPlan.getCooldownSuggestions() != null) {
                        plan.setCooldownSuggestions(updatedPlan.getCooldownSuggestions());
                    }
                    if (updatedPlan.getPrecautions() != null) {
                        plan.setPrecautions(updatedPlan.getPrecautions());
                    }

                    plan.setUpdateTime(LocalDateTime.now());
                    return trainingPlanRepository.save(plan);
                })
                .orElseThrow(() -> new RuntimeException("训练计划不存在"));
    }

    // 更新训练进度
    public TrainingPlan updateProgress(Long id, Integer completedDays) {
        return trainingPlanRepository.findById(id)
                .map(plan -> {
                    plan.setCompletedDays(completedDays);

                    // 计算进度
                    if (plan.getDurationWeeks() != null && plan.getDurationWeeks() > 0) {
                        int totalDays = plan.getDurationWeeks() * 7;
                        double progress = (double) completedDays / totalDays * 100;
                        plan.setProgress(Math.min(progress, 100.0));

                        // 如果进度达到100%，标记为完成
                        if (progress >= 100) {
                            plan.setStatus("COMPLETED");
                        }
                    }

                    plan.setUpdateTime(LocalDateTime.now());
                    return trainingPlanRepository.save(plan);
                })
                .orElseThrow(() -> new RuntimeException("训练计划不存在"));
    }

    // 标记为完成
    public TrainingPlan markAsCompleted(Long id) {
        return trainingPlanRepository.findById(id)
                .map(plan -> {
                    plan.setStatus("COMPLETED");
                    plan.setProgress(100.0);
                    plan.setUpdateTime(LocalDateTime.now());
                    return trainingPlanRepository.save(plan);
                })
                .orElseThrow(() -> new RuntimeException("训练计划不存在"));
    }

    // 暂停训练计划
    public TrainingPlan pausePlan(Long id) {
        return trainingPlanRepository.findById(id)
                .map(plan -> {
                    plan.setStatus("PAUSED");
                    plan.setUpdateTime(LocalDateTime.now());
                    return trainingPlanRepository.save(plan);
                })
                .orElseThrow(() -> new RuntimeException("训练计划不存在"));
    }

    // 恢复训练计划
    public TrainingPlan resumePlan(Long id) {
        return trainingPlanRepository.findById(id)
                .map(plan -> {
                    plan.setStatus("ACTIVE");
                    plan.setUpdateTime(LocalDateTime.now());
                    return trainingPlanRepository.save(plan);
                })
                .orElseThrow(() -> new RuntimeException("训练计划不存在"));
    }

    // AI训练推荐（基于简单规则）
    public String recommendTraining(User member) {
        String goal = member.getFitnessGoal();
        Double weight = member.getWeight();
        Double height = member.getHeight();
        Integer age = member.getAge();

        if (goal == null) {
            goal = "保持健康";
        }

        StringBuilder recommendation = new StringBuilder();
        recommendation.append("💪 基于您的信息，推荐训练计划：\n\n");

        // 计算BMI
        if (height != null && weight != null && height > 0) {
            double bmi = weight / ((height / 100) * (height / 100));
            recommendation.append("📊 您的BMI: ").append(String.format("%.1f", bmi)).append("\n");

            if (bmi < 18.5) {
                recommendation.append("⚠️  体重偏轻，建议增加肌肉训练\n");
            } else if (bmi > 24) {
                recommendation.append("⚠️  体重偏重，建议增加有氧运动\n");
            }
        }

        // 基于目标推荐
        switch (goal.toLowerCase()) {
            case "减脂":
                recommendation.append("🎯 目标：减脂\n");
                recommendation.append("🏃 训练建议：\n");
                recommendation.append("  • 每周4-5次有氧运动（跑步、游泳、动感单车）\n");
                recommendation.append("  • 每次45-60分钟\n");
                recommendation.append("  • 心率保持在120-150次/分钟\n");
                recommendation.append("  • 配合力量训练，每周2-3次\n");
                recommendation.append("🍎 饮食建议：\n");
                recommendation.append("  • 控制碳水化合物摄入\n");
                recommendation.append("  • 增加蛋白质摄入\n");
                recommendation.append("  • 多喝水，少喝含糖饮料\n");
                break;

            case "增肌":
                recommendation.append("🎯 目标：增肌\n");
                recommendation.append("🏋️ 训练建议：\n");
                recommendation.append("  • 每周4-5次力量训练\n");
                recommendation.append("  • 重点训练：卧推、深蹲、硬拉、引体向上\n");
                recommendation.append("  • 每组8-12次，每个动作3-4组\n");
                recommendation.append("  • 组间休息60-90秒\n");
                recommendation.append("🍗 饮食建议：\n");
                recommendation.append("  • 增加蛋白质摄入（体重×1.5-2克/天）\n");
                recommendation.append("  • 适量碳水化合物提供能量\n");
                recommendation.append("  • 训练后30分钟内补充蛋白质\n");
                break;

            case "塑形":
                recommendation.append("🎯 目标：塑形\n");
                recommendation.append("🤸 训练建议：\n");
                recommendation.append("  • 每周3-4次全身训练\n");
                recommendation.append("  • 结合力量和有氧训练\n");
                recommendation.append("  • 重点：核心训练、臀部训练\n");
                recommendation.append("  • 每组12-15次，中等重量\n");
                recommendation.append("🥗 饮食建议：\n");
                recommendation.append("  • 均衡饮食，控制总热量\n");
                recommendation.append("  • 多吃蔬菜水果\n");
                recommendation.append("  • 减少加工食品\n");
                break;

            default:
                recommendation.append("🎯 目标：保持健康\n");
                recommendation.append("🏃 训练建议：\n");
                recommendation.append("  • 每周3-4次运动\n");
                recommendation.append("  • 每次30-45分钟\n");
                recommendation.append("  • 结合有氧和力量训练\n");
                recommendation.append("  • 保持中等强度\n");
                recommendation.append("🥦 饮食建议：\n");
                recommendation.append("  • 均衡营养，多样化饮食\n");
                recommendation.append("  • 控制盐、糖、油摄入\n");
                recommendation.append("  • 每天喝足水\n");
        }

        return recommendation.toString();
    }

    // 获取统计数据
    public Map<String, Object> getStats(Long memberId) {
        Map<String, Object> stats = new HashMap<>();

        List<TrainingPlan> allPlans = trainingPlanRepository.findByMemberId(memberId);
        List<TrainingPlan> activePlans = trainingPlanRepository.findActivePlansByMember(memberId);
        Long completedCount = trainingPlanRepository.countCompletedPlansByMember(memberId);

        stats.put("totalPlans", allPlans.size());
        stats.put("activePlans", activePlans.size());
        stats.put("completedPlans", completedCount);

        // 计算平均进度
        double avgProgress = allPlans.stream()
                .mapToDouble(TrainingPlan::getProgress)
                .average()
                .orElse(0.0);
        stats.put("averageProgress", String.format("%.1f%%", avgProgress));

        // 按目标分类统计
        Map<String, Long> goalStats = allPlans.stream()
                .collect(Collectors.groupingBy(TrainingPlan::getGoal, Collectors.counting()));
        stats.put("goalDistribution", goalStats);

        return stats;
    }


}