src/visualization.py

import matplotlib.pyplot as plt
import seaborn as sns
import pandas as pd
import json
import os
from datetime import datetime

# 设置中文字体 (尝试自动寻找可用字体)
def set_chinese_font():
    plt.rcParams['font.sans-serif'] = ['Arial Unicode MS', 'SimHei', 'PingFang SC', 'Heiti TC']
    plt.rcParams['axes.unicode_minus'] = False

def plot_data_distribution(dataset_dict, save_path=None):
    """
    绘制数据集中 Positive/Neutral/Negative 的分布饼图
    """
    set_chinese_font()
    
    # 统计数量
    # 兼容 dataset_dict (DatasetDict) 或 dataset (Dataset)
    if hasattr(dataset_dict, 'keys') and 'train' in dataset_dict.keys():
        ds = dataset_dict['train']
    else:
        ds = dataset_dict
        
    # 统计数量
    if 'label' in ds.features:
        train_labels = ds['label']
    elif 'labels' in ds.features:
        train_labels = ds['labels']
    else:
        # Fallback
        train_labels = [x.get('label', x.get('labels')) for x in ds]
    
    # 映射回字符串以便显示
    id2label = {0: 'Negative (消极)', 1: 'Neutral (中性)', 2: 'Positive (积极)'}
    labels_str = [id2label.get(x, str(x)) for x in train_labels]
    
    df = pd.DataFrame({'Label': labels_str})
    counts = df['Label'].value_counts()
    
    plt.figure(figsize=(10, 6))
    plt.pie(counts, labels=counts.index, autopct='%1.1f%%', startangle=140, colors=sns.color_palette("pastel"))
    plt.title('训练集情感分布')
    plt.tight_layout()
    
    if save_path:
        print(f"Saving distribution plot to {save_path}...")
        plt.savefig(save_path)
    # plt.show()

def plot_training_history(log_history, save_path=None):
    """
    根据 Trainer 的 log_history 绘制 Loss 和 Accuracy 曲线
    """
    set_chinese_font()
    
    if not log_history:
        print("没有可用的训练日志。")
        return
    
    df = pd.DataFrame(log_history)
    
    # 过滤掉没有 loss 或 eval_accuracy 的行
    train_loss = df[df['loss'].notna()]
    eval_acc = df[df['eval_accuracy'].notna()]
    
    plt.figure(figsize=(14, 5))
    
    # 1. Loss Curve
    plt.subplot(1, 2, 1)
    plt.plot(train_loss['epoch'], train_loss['loss'], label='Training Loss', color='salmon')
    if 'eval_loss' in df.columns:
        eval_loss = df[df['eval_loss'].notna()]
        plt.plot(eval_loss['epoch'], eval_loss['eval_loss'], label='Validation Loss', color='skyblue')
    plt.title('训练损失 (Loss) 曲线')
    plt.xlabel('Epoch')
    plt.ylabel('Loss')
    plt.legend()
    plt.grid(True, alpha=0.3)
    
    # 2. Accuracy Curve
    if not eval_acc.empty:
        plt.subplot(1, 2, 2)
        plt.plot(eval_acc['epoch'], eval_acc['eval_accuracy'], label='Validation Accuracy', color='lightgreen', marker='o')
        plt.title('验证集准确率 (Accuracy)')
        plt.xlabel('Epoch')
        plt.ylabel('Accuracy')
        plt.legend()
        plt.grid(True, alpha=0.3)
    
    # 确保目录存在
    save_dir = os.path.join(Config.RESULTS_DIR, "images")
    if not os.path.exists(save_dir):
        os.makedirs(save_dir)

    plt.tight_layout()
    
    # 生成时间戳 string，例如: 2024-12-18_14-30-00
    timestamp = datetime.now().strftime("%Y-%m-%d_%H-%M-%S")

    # 默认保存路径
    if save_path is None:
        save_path = os.path.join(save_dir, f"training_metrics_{timestamp}.png")
        
    print(f"Saving plot to {save_path}...")
    plt.savefig(save_path)
    
    # 也可以保存一份 JSON 或 TXT 格式的最终指标
    if not eval_acc.empty:
        final_acc = eval_acc.iloc[-1]['eval_accuracy']
        final_loss = eval_acc.iloc[-1]['eval_loss'] if 'eval_loss' in eval_acc.columns else "N/A"
        metrics_file = os.path.join(save_dir, f"metrics_{timestamp}.txt")
        with open(metrics_file, "w") as f:
            f.write(f"Timestamp: {timestamp}\n")
            f.write(f"Final Validation Accuracy: {final_acc:.4f}\n")
            f.write(f"Final Validation Loss: {final_loss}\n")
            f.write(f"Plot saved to: {os.path.basename(save_path)}\n")
        print(f"Saved metrics text to {metrics_file}")

def load_and_plot_logs(log_dir):
    """
    从 checkpoint 目录加载 trainer_state.json 并绘图
    """
    json_path = os.path.join(log_dir, 'trainer_state.json')
    if not os.path.exists(json_path):
        print(f"未找到日志文件: {json_path}")
        return
        
    with open(json_path, 'r') as f:
        data = json.load(f)
        
    plot_training_history(data['log_history'])

if __name__ == "__main__":
    import sys
    import os  # Explicitly import os here if not globally sufficient or for clarity
    # 如果直接运行此脚本，解决相对导入问题
    # 将上一级目录加入 sys.path
    project_root = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
    sys.path.append(project_root)
    
    from src.config import Config
    # ---------------------------------------------------------
    # 2. 生成数据分布图 (Data Distribution)
    # ---------------------------------------------------------
    try:
        print("\n正在加载数据集以生成样本分布分析...")
        from transformers import AutoTokenizer
        from src.dataset import DataProcessor
        
        tokenizer = AutoTokenizer.from_pretrained(Config.BASE_MODEL)
        processor = DataProcessor(tokenizer)
        # 尝试从 data 目录加载处理好的数据 (快)
        dataset = processor.get_processed_dataset(cache_dir=Config.DATA_DIR)
        
        # 生成带时间戳的文件名
        timestamp = datetime.now().strftime("%Y-%m-%d_%H-%M-%S")
        dist_save_path = os.path.join(Config.RESULTS_DIR, "images", f"data_distribution_{timestamp}.png")
        
        # 绘图并保存
        plot_data_distribution(dataset, save_path=dist_save_path)
        print(f"数据样本分布分析已保存至: {dist_save_path}")
        
    except Exception as e:
        print(f"无法生成数据分布图 (可能是数据尚未下载或处理): {e}")

    # ---------------------------------------------------------
    # 3. 生成训练曲线 (Training History)
    # ---------------------------------------------------------
    import glob
    
    # 找最新的 checkpoints
    search_paths = [
        Config.OUTPUT_DIR,
        os.path.join(Config.RESULTS_DIR, "checkpoint-*")
    ]
    
    candidates = []
    for p in search_paths:
        candidates.extend(glob.glob(p))
    
    if candidates:
        # 找最新的
        candidates.sort(key=os.path.getmtime)
        latest_ckpt = candidates[-1]
        print(f"Loading logs from: {latest_ckpt}")
        load_and_plot_logs(latest_ckpt)
    else:
        print("未找到任何 checkpoint 或 trainer_state.json 日志文件。")