#include "importdialog.h"
#include <QVBoxLayout>
#include <QHBoxLayout>
#include <QFormLayout>
#include <QLabel>
#include <QFileDialog>
#include <QMessageBox>
#include <QFile>
#include <QTextStream>
#include <QHeaderView>
#include <QGroupBox>
#include <QDate>

ImportDialog::ImportDialog(Database *db, QWidget *parent)
    : QDialog(parent)
    , database(db)
{
    setWindowTitle("Import CSV");
    resize(900, 600);
    
    QVBoxLayout *mainLayout = new QVBoxLayout(this);
    
    // File selection
    QHBoxLayout *fileLayout = new QHBoxLayout();
    QLabel *fileLabel = new QLabel("CSV File:");
    browseBtn = new QPushButton("Browse...");
    connect(browseBtn, &QPushButton::clicked, this, &ImportDialog::onBrowseFile);
    fileLayout->addWidget(fileLabel);
    fileLayout->addWidget(browseBtn);
    fileLayout->addStretch();
    mainLayout->addLayout(fileLayout);
    
    // Column mapping section
    QGroupBox *mappingBox = new QGroupBox("Column Mapping");
    QFormLayout *mappingLayout = new QFormLayout();
    
    dateColumnCombo = new QComboBox();
    amountColumnCombo = new QComboBox();
    withdrawalColumnCombo = new QComboBox();
    depositColumnCombo = new QComboBox();
    descriptionColumnCombo = new QComboBox();
    
    mappingLayout->addRow("Date Column:", dateColumnCombo);
    mappingLayout->addRow("Amount Column (or use Withdrawal/Deposit):", amountColumnCombo);
    mappingLayout->addRow("Withdrawal Column:", withdrawalColumnCombo);
    mappingLayout->addRow("Deposit Column:", depositColumnCombo);
    mappingLayout->addRow("Description Column:", descriptionColumnCombo);
    
    mappingBox->setLayout(mappingLayout);
    mainLayout->addWidget(mappingBox);
    
    // Default values section
    QGroupBox *defaultsBox = new QGroupBox("Default Values");
    QFormLayout *defaultsLayout = new QFormLayout();
    
    accountCombo = new QComboBox();
    accountCombo->setEditable(true);
    categoryCombo = new QComboBox();
    categoryCombo->setEditable(true);
    
    // Populate from database
    QSet<QString> accounts;
    QSet<QString> categories;
    for (const Transaction &t : database->getAllTransactions()) {
        if (!t.account.isEmpty()) accounts.insert(t.account);
        if (!t.category.isEmpty()) categories.insert(t.category);
    }
    accountCombo->addItems(accounts.values());
    categoryCombo->addItems(categories.values());
    
    defaultsLayout->addRow("Account:", accountCombo);
    defaultsLayout->addRow("Category:", categoryCombo);
    
    defaultsBox->setLayout(defaultsLayout);
    mainLayout->addWidget(defaultsBox);
    
    // Preview table
    QLabel *previewLabel = new QLabel("Preview (check rows to import):");
    mainLayout->addWidget(previewLabel);
    
    previewTable = new QTableWidget();
    previewTable->setSelectionBehavior(QAbstractItemView::SelectRows);
    mainLayout->addWidget(previewTable);
    
    // Selection buttons
    QHBoxLayout *selectionLayout = new QHBoxLayout();
    selectAllBtn = new QPushButton("Select All");
    deselectAllBtn = new QPushButton("Deselect All");
    connect(selectAllBtn, &QPushButton::clicked, this, &ImportDialog::onSelectAll);
    connect(deselectAllBtn, &QPushButton::clicked, this, &ImportDialog::onDeselectAll);
    selectionLayout->addWidget(selectAllBtn);
    selectionLayout->addWidget(deselectAllBtn);
    selectionLayout->addStretch();
    mainLayout->addLayout(selectionLayout);
    
    // Dialog buttons
    QHBoxLayout *buttonLayout = new QHBoxLayout();
    importBtn = new QPushButton("Import");
    importBtn->setEnabled(false);
    QPushButton *cancelBtn = new QPushButton("Cancel");
    connect(importBtn, &QPushButton::clicked, this, &ImportDialog::onImport);
    connect(cancelBtn, &QPushButton::clicked, this, &QDialog::reject);
    buttonLayout->addStretch();
    buttonLayout->addWidget(importBtn);
    buttonLayout->addWidget(cancelBtn);
    mainLayout->addLayout(buttonLayout);
    
    // Connect column mapping changes
    connect(dateColumnCombo, QOverload<int>::of(&QComboBox::currentIndexChanged), 
            this, &ImportDialog::onColumnMappingChanged);
    connect(amountColumnCombo, QOverload<int>::of(&QComboBox::currentIndexChanged), 
            this, &ImportDialog::onColumnMappingChanged);
    connect(withdrawalColumnCombo, QOverload<int>::of(&QComboBox::currentIndexChanged), 
            this, &ImportDialog::onColumnMappingChanged);
    connect(depositColumnCombo, QOverload<int>::of(&QComboBox::currentIndexChanged), 
            this, &ImportDialog::onColumnMappingChanged);
    connect(descriptionColumnCombo, QOverload<int>::of(&QComboBox::currentIndexChanged), 
            this, &ImportDialog::onColumnMappingChanged);
}

ImportDialog::~ImportDialog()
{
}

void ImportDialog::onBrowseFile()
{
    QString fileName = QFileDialog::getOpenFileName(
        this,
        "Select CSV File",
        QDir::homePath(),
        "CSV Files (*.csv);;All Files (*)"
    );
    
    if (!fileName.isEmpty()) {
        loadCsvFile(fileName);
    }
}

void ImportDialog::loadCsvFile(const QString &filePath)
{
    QFile file(filePath);
    if (!file.open(QIODevice::ReadOnly | QIODevice::Text)) {
        QMessageBox::critical(this, "Error", "Failed to open file: " + file.errorString());
        return;
    }
    
    QTextStream in(&file);
    csvRows.clear();
    csvHeaders.clear();
    
    // Read header
    if (!in.atEnd()) {
        QString line = in.readLine();
        csvHeaders = line.split(',');
        // Trim whitespace and quotes
        for (QString &header : csvHeaders) {
            header = header.trimmed();
            if (header.startsWith('"') && header.endsWith('"')) {
                header = header.mid(1, header.length() - 2);
            }
        }
    }
    
    // Read data rows
    while (!in.atEnd()) {
        QString line = in.readLine();
        QStringList row = line.split(',');
        // Trim whitespace and quotes
        for (QString &cell : row) {
            cell = cell.trimmed();
            if (cell.startsWith('"') && cell.endsWith('"')) {
                cell = cell.mid(1, cell.length() - 2);
            }
        }
        if (row.size() == csvHeaders.size()) {
            csvRows.append(row);
        }
    }
    
    file.close();
    
    // Populate column mapping combos
    dateColumnCombo->clear();
    amountColumnCombo->clear();
    withdrawalColumnCombo->clear();
    depositColumnCombo->clear();
    descriptionColumnCombo->clear();
    
    dateColumnCombo->addItem("(None)", -1);
    amountColumnCombo->addItem("(None)", -1);
    withdrawalColumnCombo->addItem("(None)", -1);
    depositColumnCombo->addItem("(None)", -1);
    descriptionColumnCombo->addItem("(None)", -1);
    
    for (int i = 0; i < csvHeaders.size(); i++) {
        dateColumnCombo->addItem(csvHeaders[i], i);
        amountColumnCombo->addItem(csvHeaders[i], i);
        withdrawalColumnCombo->addItem(csvHeaders[i], i);
        depositColumnCombo->addItem(csvHeaders[i], i);
        descriptionColumnCombo->addItem(csvHeaders[i], i);
    }
    
    // Try to auto-detect columns
    for (int i = 0; i < csvHeaders.size(); i++) {
        QString header = csvHeaders[i].toLower();
        if (header.contains("date") || header.contains("transaction date")) {
            dateColumnCombo->setCurrentIndex(i + 1);
        } else if (header.contains("withdrawal") || header.contains("debit") || header.contains("withdrawals")) {
            withdrawalColumnCombo->setCurrentIndex(i + 1);
        } else if (header.contains("deposit") || header.contains("credit") || header.contains("deposits")) {
            depositColumnCombo->setCurrentIndex(i + 1);
        } else if (header.contains("amount")) {
            amountColumnCombo->setCurrentIndex(i + 1);
        } else if (header.contains("description") || header.contains("memo") || header.contains("payee")) {
            descriptionColumnCombo->setCurrentIndex(i + 1);
        }
    }
    
    updatePreview();
    importBtn->setEnabled(true);
}

void ImportDialog::updatePreview()
{
    if (csvRows.isEmpty()) {
        return;
    }
    
    // Setup preview table
    previewTable->clear();
    previewTable->setColumnCount(csvHeaders.size() + 4); // +4 for checkbox, parsed date, amount, description
    previewTable->setRowCount(csvRows.size());
    
    QStringList headers;
    headers << "Import" << "Parsed Date" << "Parsed Amount" << "Parsed Description";
    headers.append(csvHeaders);
    previewTable->setHorizontalHeaderLabels(headers);
    
    int dateCol = dateColumnCombo->currentData().toInt();
    int amountCol = amountColumnCombo->currentData().toInt();
    int withdrawalCol = withdrawalColumnCombo->currentData().toInt();
    int depositCol = depositColumnCombo->currentData().toInt();
    int descCol = descriptionColumnCombo->currentData().toInt();
    
    for (int row = 0; row < csvRows.size(); row++) {
        // Checkbox
        QCheckBox *checkbox = new QCheckBox();
        checkbox->setChecked(true);
        QWidget *checkboxWidget = new QWidget();
        QHBoxLayout *layout = new QHBoxLayout(checkboxWidget);
        layout->addWidget(checkbox);
        layout->setAlignment(Qt::AlignCenter);
        layout->setContentsMargins(0, 0, 0, 0);
        previewTable->setCellWidget(row, 0, checkboxWidget);
        
        // Parse and show interpreted values
        QString parsedDate = "";
        QString parsedAmount = "";
        QString parsedDesc = "";
        
        if (dateCol >= 0 && dateCol < csvRows[row].size()) {
            QDate date = QDate::fromString(csvRows[row][dateCol], "yyyy-MM-dd");
            if (!date.isValid()) {
                date = QDate::fromString(csvRows[row][dateCol], "MM/dd/yyyy");
            }
            if (!date.isValid()) {
                date = QDate::fromString(csvRows[row][dateCol], "M/d/yyyy");
            }
            if (date.isValid()) {
                parsedDate = date.toString("yyyy-MM-dd");
            }
        }
        
        // Use withdrawal/deposit if either is selected, otherwise use amount
        if (withdrawalCol >= 0 || depositCol >= 0) {
            // Parse withdrawal and deposit columns
            double withdrawal = 0.0;
            double deposit = 0.0;
            
            if (withdrawalCol >= 0 && withdrawalCol < csvRows[row].size()) {
                QString withdrawalStr = csvRows[row][withdrawalCol];
                withdrawalStr.replace("$", "").replace(",", "").replace(" ", "");
                if (!withdrawalStr.isEmpty()) {
                    bool ok;
                    withdrawal = withdrawalStr.toDouble(&ok);
                    if (!ok) withdrawal = 0.0;
                }
            }
            
            if (depositCol >= 0 && depositCol < csvRows[row].size()) {
                QString depositStr = csvRows[row][depositCol];
                depositStr.replace("$", "").replace(",", "").replace(" ", "");
                if (!depositStr.isEmpty()) {
                    bool ok;
                    deposit = depositStr.toDouble(&ok);
                    if (!ok) deposit = 0.0;
                }
            }
            
            // Calculate net amount (deposit is positive, withdrawal is negative)
            double amount = deposit - withdrawal;
            parsedAmount = QString::number(amount, 'f', 2);
        } else if (amountCol >= 0 && amountCol < csvRows[row].size()) {
            // Parse single amount column
            QString amountStr = csvRows[row][amountCol];
            amountStr.replace("$", "").replace(",", "").replace(" ", "");
            bool ok;
            double amount = amountStr.toDouble(&ok);
            if (ok) {
                parsedAmount = QString::number(amount, 'f', 2);
            }
        }
        
        if (descCol >= 0 && descCol < csvRows[row].size()) {
            parsedDesc = csvRows[row][descCol];
        }
        
        previewTable->setItem(row, 1, new QTableWidgetItem(parsedDate));
        previewTable->setItem(row, 2, new QTableWidgetItem(parsedAmount));
        previewTable->setItem(row, 3, new QTableWidgetItem(parsedDesc));
        
        // Original CSV columns
        for (int col = 0; col < csvRows[row].size(); col++) {
            previewTable->setItem(row, col + 4, new QTableWidgetItem(csvRows[row][col]));
        }
    }
    
    previewTable->resizeColumnsToContents();
}

void ImportDialog::onColumnMappingChanged()
{
    updatePreview();
}

void ImportDialog::onImport()
{
    importedTransactions.clear();
    
    int dateCol = dateColumnCombo->currentData().toInt();
    int amountCol = amountColumnCombo->currentData().toInt();
    int withdrawalCol = withdrawalColumnCombo->currentData().toInt();
    int depositCol = depositColumnCombo->currentData().toInt();
    int descCol = descriptionColumnCombo->currentData().toInt();
    
    if (dateCol < 0) {
        QMessageBox::warning(this, "Missing Mapping", "Date column is required.");
        return;
    }
    
    // Check if either amount OR withdrawal/deposit columns are specified
    if (amountCol < 0 && withdrawalCol < 0 && depositCol < 0) {
        QMessageBox::warning(this, "Missing Mapping", "Either Amount column or Withdrawal/Deposit columns are required.");
        return;
    }
    
    QString defaultAccount = accountCombo->currentText();
    QString defaultCategory = categoryCombo->currentText();
    
    int importCount = 0;
    for (int row = 0; row < previewTable->rowCount(); row++) {
        QWidget *widget = previewTable->cellWidget(row, 0);
        QCheckBox *checkbox = widget->findChild<QCheckBox*>();
        
        if (checkbox && checkbox->isChecked()) {
            Transaction t;
            t.id = -1;
            
            // Parse date
            QString dateStr = csvRows[row][dateCol];
            t.date = QDate::fromString(dateStr, "yyyy-MM-dd");
            if (!t.date.isValid()) {
                t.date = QDate::fromString(dateStr, "MM/dd/yyyy");
            }
            if (!t.date.isValid()) {
                t.date = QDate::fromString(dateStr, "M/d/yyyy");
            }
            
            // Parse amount - use withdrawal/deposit if either is selected, otherwise use amount
            if (withdrawalCol >= 0 || depositCol >= 0) {
                double withdrawal = 0.0;
                double deposit = 0.0;
                
                if (withdrawalCol >= 0 && withdrawalCol < csvRows[row].size()) {
                    QString withdrawalStr = csvRows[row][withdrawalCol];
                    withdrawalStr.replace("$", "").replace(",", "").replace(" ", "");
                    if (!withdrawalStr.isEmpty()) {
                        withdrawal = withdrawalStr.toDouble();
                    }
                }
                
                if (depositCol >= 0 && depositCol < csvRows[row].size()) {
                    QString depositStr = csvRows[row][depositCol];
                    depositStr.replace("$", "").replace(",", "").replace(" ", "");
                    if (!depositStr.isEmpty()) {
                        deposit = depositStr.toDouble();
                    }
                }
                
                t.amount = deposit - withdrawal;
            } else if (amountCol >= 0 && amountCol < csvRows[row].size()) {
                QString amountStr = csvRows[row][amountCol];
                amountStr.replace("$", "").replace(",", "").replace(" ", "");
                t.amount = amountStr.toDouble();
            }
            
            // Parse description
            if (descCol >= 0 && descCol < csvRows[row].size()) {
                t.description = csvRows[row][descCol];
            }
            
            t.account = defaultAccount;
            t.category = defaultCategory;
            t.type = TransactionType::Actual;
            t.recurringId = -1;
            t.reconciled = false;
            t.sortOrder = 0;
            
            if (t.date.isValid()) {
                importedTransactions.append(t);
                importCount++;
            }
        }
    }
    
    if (importCount == 0) {
        QMessageBox::information(this, "No Rows Selected", "No valid rows were selected for import.");
        return;
    }
    
    QMessageBox::information(this, "Import Complete", 
                            QString("Successfully imported %1 transactions.").arg(importCount));
    accept();
}

void ImportDialog::onSelectAll()
{
    for (int row = 0; row < previewTable->rowCount(); row++) {
        QWidget *widget = previewTable->cellWidget(row, 0);
        QCheckBox *checkbox = widget->findChild<QCheckBox*>();
        if (checkbox) {
            checkbox->setChecked(true);
        }
    }
}

void ImportDialog::onDeselectAll()
{
    for (int row = 0; row < previewTable->rowCount(); row++) {
        QWidget *widget = previewTable->cellWidget(row, 0);
        QCheckBox *checkbox = widget->findChild<QCheckBox*>();
        if (checkbox) {
            checkbox->setChecked(false);
        }
    }
}

QList<Transaction> ImportDialog::getImportedTransactions() const
{
    return importedTransactions;
}