import os
import pandas as pd
import glob
import sys
from PyQt5.QtWidgets import (QApplication, QWidget, QVBoxLayout, QPushButton, 
                               QLabel, QFileDialog, QMessageBox)
from PyQt5.QtCore import Qt

class MergeTransactionsApp(QWidget):
    def __init__(self):
        super().__init__()
        self.input_dir = ""
        self.output_dir = ""
        self.init_ui()

    def init_ui(self):
        self.setWindowTitle("Excel Transaction Merger")
        self.resize(500, 300)
        layout = QVBoxLayout()

        # Input Directory
        self.input_label = QLabel(f"Input Directory: {self.input_dir if self.input_dir else 'Not Selected'}")
        layout.addWidget(self.input_label)
        btn_input = QPushButton("Select Input Directory")
        btn_input.clicked.connect(self.select_input_dir)
        layout.addWidget(btn_input)

        # Output Directory
        self.output_label = QLabel(f"Output Directory: {self.output_dir if self.output_dir else 'Not Selected'}")
        layout.addWidget(self.output_label)
        btn_output = QPushButton("Select Output Directory")
        btn_output.clicked.connect(self.select_output_dir)
        layout.addWidget(btn_output)

        # Process Button
        self.process_btn = QPushButton("Start Merging")
        self.process_btn.setStyleSheet("background-color: #4CAF50; color: white; font-weight: bold;")
        self.process_btn.clicked.connect(self.run_merge)
        layout.addWidget(self.process_btn)

        self.setLayout(layout)

    def select_input_dir(self):
        path = QFileDialog.getExistingDirectory(self, "Select Input Directory")
        if path:
            self.input_dir = path
            self.input_label.setText(f"Input Directory: {path}")

    def select_output_dir(self):
        path = QFileDialog.getExistingDirectory(self, "Select Output Directory")
        if path:
            self.output_dir = path
            self.output_label.setText(f"Output Directory: {path}")

    def run_merge(self):
        if not self.input_dir or not self.output_dir:
            QMessageBox.warning(self, "Error", "Please select both input and output directories.")
            return

        success = self.process_files()
        if success:
            QMessageBox.information(self, "Success", "Merge completed successfully!")
        else:
            QMessageBox.critical(self, "Error", "An error occurred during the merge process.")

    def process_files(self):
        try:
            input_path = os.path.abspath(self.input_dir)
            if not os.path.isdir(input_path):
                print(f"Error: {input_path} is not a valid directory.")
                return False

            # Support .xlsx and .xls formats
            file_pattern = os.path.join(input_path, "*.xls*")
            files = glob.glob(file_pattern)
            
            all_data = []
            target_sheet = "交易流水"

            for file_path in files:
                filename = os.path.basename(file_path)
                
                # Skip temporary excel files (starting with ~$) and the output summary file
                if filename.startswith("~$") or "txn_summary" in filename:
                    continue
                    
                try:
                    # Load Excel File
                    xls = pd.ExcelFile(file_path)
                    if target_sheet in xls.sheet_names:
                        # Use dtype=str to ensure all fields are read as strings (prevents scientific notation)
                        df = pd.read_excel(xls, sheet_name=target_sheet, dtype=str)
                        
                        # Record source filename for tracking
                        df['source_file'] = filename
                        all_data.append(df)
                        print(f"Successfully read: {filename}")
                    else:
                        print(f"Skipping file {filename}: Sheet '{target_sheet}' not found.")
                except Exception as e:
                    print(f"Error processing {filename}: {e}")

            if all_data:
                # Concatenate all DataFrames
                merged_df = pd.concat(all_data, ignore_index=True)
                
                # Define output path in the selected directory
                output_path = os.path.join(self.output_dir, "txn_summary.xlsx")
                
                # Save to Excel
                with pd.ExcelWriter(output_path, engine='openpyxl') as writer:
                    merged_df.to_excel(writer, sheet_name='Summary', index=False)
                
                print("-" * 30)
                print(f"Merge complete! Result saved to: {output_path}")
                return True
            else:
                print("No files containing the '交易流水' sheet were found.")
                return False

        except Exception as e:
            print(f"Critical error during processing: {e}")
            return False

if __name__ == "__main__":
    app = QApplication(sys.argv)
    window = MergeTransactionsApp()
    window.show()
    sys.exit(app.exec_())