import os
import sqlite3
from flask import Flask, jsonify, request, send_file, g
from werkzeug.utils import secure_filename
from flask_cors import CORS
import pandas as pd
from io import BytesIO
import logging

app = Flask(__name__)

# 设置数据库文件和上传文件夹的路径
DATABASE = 'SoilAcidification.db'
UPLOAD_FOLDER = 'uploads'
app.config['UPLOAD_FOLDER'] = UPLOAD_FOLDER
os.makedirs(app.config['UPLOAD_FOLDER'], exist_ok=True)

# 跨源资源共享（CORS）配置，允许跨域请求
CORS(app)

# 设置日志
logging.basicConfig(level=logging.DEBUG, format='%(asctime)s - %(levelname)s - %(message)s')
logging.basicConfig(level=logging.INFO)
logger = logging.getLogger(__name__)

# 创建一个数据库连接池
def get_db():
    db = getattr(g, '_database', None)
    if db is None:
        db = g._database = sqlite3.connect(DATABASE)
    return db

# 获取列名的函数
def get_column_names(table_name):
    db = get_db()
    cur = db.cursor()
    cur.execute(f"PRAGMA table_info({table_name});")
    columns = [column[1] for column in cur.fetchall()]
    db.close()
    return columns

@app.after_request
def add_headers(response):
    response.headers['Content-Type'] = 'application/json; charset=utf-8'
    return response

@app.route('/')
def index():
    return 'Hello, World!'

# 有这个函数来获取列名
def get_column_names(table_name):
    """
    根据表名获取对应的列名（字段）。
    """
    if table_name == 'current_reflux':
        # 返回列名映射
        return ['OM', 'CL', 'CEC', 'H_plus', 'HN', 'Al3_plus', 'Free_alumina', 'Free_iron_oxides', 'Delta_pH'], \
               ["有机质含量", "土壤粘粒重量", "阳离子交换量", "氢离子含量", "硝态氮含量", "铝离子含量", "游离氧化铝", "游离氧化铁", "酸碱差值"]
    elif table_name == 'current_reduce':
        # 返回列名映射
        return ['Q_over_b', 'pH', 'OM', 'CL', 'H', 'Al'], \
               ["比值", "酸碱度", "有机质含量", "氯离子含量", "氢离子含量", "铝离子含量"]
    else:
        return [], []  # 不支持的表名，返回空列表


@app.route('/download_template', methods=['GET'])
def download_template():
        """
        根据表名生成模板文件（Excel 或 CSV），并返回下载。
        :return: 返回模板文件
        """
        table_name = request.args.get('table')  # 从请求参数中获取表名
        if not table_name:
            return jsonify({'error': '表名参数缺失'}), 400

        # 获取表的列名
        try:
            column_names = get_column_names(table_name)
        except sqlite3.Error as e:
            return jsonify({'error': f'获取列名失败: {str(e)}'}), 400

        if not column_names:
            return jsonify({'error': f'未找到表 {table_name} 或列名为空'}), 400

        # 根据表名映射列名（可自定义标题）
        if table_name == 'current_reflux':
            column_titles = ["有机质含量", "土壤粘粒重量", "阳离子交换量", "氢离子含量", "硝态氮含量", "铝离子含量",
                             "游离氧化铝", "游离氧化铁", "酸碱差值"]
        elif table_name == 'current_reduce':
            column_titles = ["比值", "酸碱度", "有机质含量", "氯离子含量", "氢离子含量1", "铝离子含量1"]
        else:
            return jsonify({'error': f'不支持的表名 {table_name}'}), 400

        # 使用 pandas 创建一个空的 DataFrame，列名为自定义的标题
        df = pd.DataFrame(columns=column_titles)

        # 根据需求选择模板格式：Excel 或 CSV
        file_format = request.args.get('format', 'excel').lower()
        if file_format == 'csv':
            # 将 DataFrame 写入内存中的 CSV 文件
            output = BytesIO()
            df.to_csv(output, index=False, encoding='utf-8')
            output.seek(0)  # 返回文件开头
            return send_file(output, as_attachment=True, download_name=f'{table_name}_template.csv',
                             mimetype='text/csv')

        else:
            # 默认生成 Excel 文件
            output = BytesIO()
            df.to_excel(output, index=False, engine='openpyxl')
            output.seek(0)  # 返回文件开头
            return send_file(output, as_attachment=True, download_name=f'{table_name}_template.xlsx',
                             mimetype='application/vnd.openxmlformats-officedocument.spreadsheetml.sheet')

# 模板下载接口
@app.route('/import_data', methods=['POST'])
def import_data():
    """
    导入数据接口，根据表名将 Excel 或 CSV 数据导入到对应的数据库表中。
    """
    # 检查是否有文件
    if 'file' not in request.files:
        logging.error("请求中没有文件")
        return jsonify({'success': False, 'message': '文件缺失'}), 400

    file = request.files['file']
    table_name = request.form.get('table')

    # 检查表名参数
    if not table_name:
        logging.error("缺少表名参数")
        return jsonify({'success': False, 'message': '缺少表名参数'}), 400

    # 检查文件是否为空
    if file.filename == '':
        logging.error("文件为空")
        return jsonify({'success': False, 'message': '未选择文件'}), 400

    # 获取表的字段映射
    db_columns, display_titles = get_column_names(table_name)

    # 校验是否支持该表名
    if not db_columns:
        logging.error(f"不支持的表名: {table_name}")
        return jsonify({'success': False, 'message': f'不支持的表名: {table_name}'}), 400

    logging.info(f"表名 {table_name} 对应的字段: {db_columns}")

    # 中文列名到数据库列名的映射
    column_name_mapping = {
        "有机质含量": "OM",
        "土壤粘粒重量": "CL",
        "阳离子交换量": "CEC",
        "氢离子含量": "H_plus",
        "硝态氮含量": "HN",
        "铝离子含量": "Al3_plus",
        "游离氧化铝": "Free_alumina",
        "游离氧化铁": "Free_iron_oxides",
        "酸碱差值": "Delta_pH",
        "比值": "Q_over_b",
        "酸碱度": "pH",
        "氯离子含量": "CL",
        "氢离子含量1": "H",
        "铝离子含量1": "Al"
    }

    try:
        # 保存上传文件到临时目录
        temp_path = os.path.join(app.config['UPLOAD_FOLDER'], secure_filename(file.filename))
        logging.info(f"正在保存文件到临时路径: {temp_path}")
        file.save(temp_path)

        # 读取文件内容（支持 Excel 和 CSV 格式）
        if file.filename.endswith('.xlsx'):
            logging.info(f"读取 Excel 文件: {file.filename}")
            df = pd.read_excel(temp_path)
        elif file.filename.endswith('.csv'):
            logging.info(f"读取 CSV 文件: {file.filename}")
            df = pd.read_csv(temp_path)
        else:
            logging.error("仅支持 Excel 和 CSV 文件")
            return jsonify({'success': False, 'message': '仅支持 Excel 和 CSV 文件'}), 400

        logging.info(f"文件读取成功，列名: {df.columns.tolist()}")

        # 1. 移除“序号”列（如果存在）
        if '序号' in df.columns:
            df = df.drop(columns=['序号'])

        # 2. 将文件中的列名（中文）转换为数据库列名（英文）
        df.columns = [column_name_mapping.get(col, col) for col in df.columns]

        logging.info(f"转换后的列名: {df.columns.tolist()}")

        # 校验文件的列是否与数据库表字段匹配
        if not set(db_columns).issubset(set(df.columns)):
            logging.error(f"文件列名与数据库表不匹配. 文件列: {df.columns.tolist()}, 期望列: {db_columns}")
            return jsonify({'success': False, 'message': '文件列名与数据库表不匹配'}), 400

        logging.info("开始清洗数据：移除空行并按需要格式化")
        # 数据清洗：移除空行并按需要格式化
        df_cleaned = df[db_columns].dropna()
        logging.info(f"清洗后数据行数: {len(df_cleaned)}")

        # 插入数据到数据库
        conn = get_db()
        logging.info(f"开始将数据插入到表 {table_name} 中")

        # 使用事务确保操作的一致性
        with conn:
            df_cleaned.to_sql(table_name, conn, if_exists='append', index=False)

        logging.info(f"数据成功插入到表 {table_name} 中，插入行数: {len(df_cleaned)}")

        # 删除临时文件
        os.remove(temp_path)
        logging.info(f"临时文件 {temp_path} 删除成功")

        return jsonify({'success': True, 'message': '数据导入成功'}), 200

    except Exception as e:
        logging.error(f"导入失败: {e}", exc_info=True)  # 捕获堆栈信息，方便调试
        return jsonify({'success': False, 'message': f'导入失败: {str(e)}'}), 500


# 导出数据接口
@app.route('/export_data', methods=['GET'])
def export_data():
    """
    根据表名从数据库导出数据，并返回 Excel 或 CSV 格式的文件
    :return: 返回文件
    """
    # 获取表名和文件格式
    table_name = request.args.get('table')
    if not table_name:
        return jsonify({'error': '缺少表名参数'}), 400

    file_format = request.args.get('format', 'excel').lower()  # 默认生成 Excel 文件

    # 获取数据
    conn = get_db()
    query = f"SELECT * FROM {table_name};"  # 查询表中的所有数据
    df = pd.read_sql(query, conn)
    conn.close()

    if file_format == 'csv':
        # 将数据保存为 CSV 格式
        output = BytesIO()
        df.to_csv(output, index=False)
        output.seek(0)
        return send_file(output, as_attachment=True, download_name=f'{table_name}_data.csv',
                         mimetype='text/csv')

    else:
        # 默认生成 Excel 格式
        output = BytesIO()
        df.to_excel(output, index=False, engine='openpyxl')
        output.seek(0)
        return send_file(output, as_attachment=True, download_name=f'{table_name}_data.xlsx',
                         mimetype='application/vnd.openxmlformats-officedocument.spreadsheetml.sheet')

# 添加记录
@app.route('/add_item', methods=['POST'])
def add_item():
    db = get_db()
    try:
        # 确保请求体是JSON格式
        data = request.get_json()
        if not data:
            raise ValueError("No JSON data provided")

        table_name = data.get('table')
        item_data = data.get('item')

        if not table_name or not item_data:
            return jsonify({'error': 'Missing table name or item data'}), 400

        cur = db.cursor()

        # 动态构建 SQL 语句
        columns = ', '.join(item_data.keys())
        placeholders = ', '.join(['?'] * len(item_data))
        sql = f"INSERT INTO {table_name} ({columns}) VALUES ({placeholders})"
        cur.execute(sql, tuple(item_data.values()))
        db.commit()

        return jsonify({'success': True, 'message': 'Item added successfully'}), 201

    except ValueError as e:
        return jsonify({'error': str(e)}), 400
    except KeyError as e:
        return jsonify({'error': f'Missing data field: {e}'}), 400
    except sqlite3.IntegrityError as e:
        return jsonify({'error': 'Database integrity error', 'details': str(e)}), 409
    except sqlite3.Error as e:
        return jsonify({'error': 'Database error', 'details': str(e)}), 500
    finally:
        db.close()

# 删除记录
@app.route('/delete_item', methods=['POST'])
def delete_item():
    data = request.get_json()
    table_name = data.get('table')
    condition = data.get('condition')

    # 日志：检查是否收到正确的参数
    logging.debug(f"Received data: table={table_name}, condition={condition}")

    if not table_name or not condition:
        logging.error("缺少表名或条件参数")
        return jsonify({"success": False, "message": "缺少表名或条件参数"}), 400

    try:
        key, value = condition.split('=')
    except ValueError:
        logging.error(f"条件格式错误，received condition: {condition}")
        return jsonify({"success": False, "message": "条件格式错误，应为 'key=value'"}), 400

    db = get_db()
    cur = db.cursor()

    # 日志：确认开始删除操作
    logging.debug(f"Attempting to delete from {table_name} where {key} = {value}")

    try:
        cur.execute(f"DELETE FROM {table_name} WHERE {key} = ?", (value,))
        db.commit()

        # 日志：删除成功
        logging.info(f"Record deleted from {table_name} where {key} = {value}")
        return jsonify({"success": True, "message": "记录删除成功"}), 200
    except sqlite3.Error as e:
        db.rollback()
        # 日志：捕获删除失败的错误
        logging.error(f"Failed to delete from {table_name} where {key} = {value}. Error: {e}")
        return jsonify({"success": False, "message": f"删除失败: {e}"}), 400

# 更新记录
@app.route('/update_item', methods=['PUT'])
def update_record():
    data = request.get_json()

    if not data or 'table' not in data or 'item' not in data:
        return jsonify({"success": False, "message": "请求数据不完整"}), 400

    table_name = data['table']
    item = data['item']

    if not item or next(iter(item.keys())) is None:
        return jsonify({"success": False, "message": "记录数据为空"}), 400

    id_key = next(iter(item.keys()))
    record_id = item[id_key]
    updates = {key: value for key, value in item.items() if key != id_key}

    db = get_db()
    cur = db.cursor()

    try:
        record_id = int(record_id)
    except ValueError:
        return jsonify({"success": False, "message": "ID 必须是整数"}), 400

    parameters = list(updates.values()) + [record_id]
    set_clause = ','.join([f"{k} = ?" for k in updates.keys()])
    sql = f"UPDATE {table_name} SET {set_clause} WHERE {id_key} = ?"

    try:
        cur.execute(sql, parameters)
        db.commit()
        if cur.rowcount == 0:
            return jsonify({"success": False, "message": "未找到要更新的记录"}), 404
        return jsonify({"success": True, "message": "数据更新成功"}), 200
    except sqlite3.Error as e:
        db.rollback()
        return jsonify({"success": False, "message": f"更新失败: {e}"}), 400

# 查询记录
@app.route('/search/record', methods=['GET'])
def sql_search():
    try:
        data = request.get_json()
        sql_table = data['table']
        record_id = data['id']

        db = get_db()
        cur = db.cursor()

        sql = f"SELECT * FROM {sql_table} WHERE id = ?"
        cur.execute(sql, (record_id,))

        rows = cur.fetchall()
        column_names = [desc[0] for desc in cur.description]

        if not rows:
            return jsonify({'error': '未查找到对应数据。'}), 400

        results = []
        for row in rows:
            result = {column_names[i]: row[i] for i in range(len(row))}
            results.append(result)

        cur.close()
        db.close()

        return jsonify(results), 200

    except sqlite3.Error as e:
        return jsonify({'error': str(e)}), 400
    except KeyError as e:
        return jsonify({'error': f'缺少必要的数据字段: {e}'}), 400

# 提供表格数据
@app.route('/tables', methods=['POST'])
def get_table():
    data = request.get_json()
    table_name = data.get('table')

    if not table_name:
        return jsonify({'error': '需要表名'}), 400

    db = get_db()
    try:
        cur = db.cursor()
        cur.execute(f"SELECT * FROM {table_name}")
        rows = cur.fetchall()

        if not rows:
            return jsonify({'error': f'表 {table_name} 为空或不存在'}), 400

        headers = [description[0] for description in cur.description]
        return jsonify(rows=rows, headers=headers), 200
    except sqlite3.Error as e:
        return jsonify({'error': str(e)}), 400
    finally:
        db.close()

if __name__ == '__main__':
    app.run(debug=True)