// ============================================================
// SCRIPT SETTINGS
// ============================================================

// Duplicate check - specify fields to search for existing records
// Usage examples:
// var keyColumns = ["email"];           - check by email
// var keyColumns = ["order_id"];        - check by order ID
// var keyColumns = ["email", "order_id"];  - check by multiple fields
var keyColumns = []; // Duplicate check disabled

// ============================================================

// Function for sending a response
function sendResponse(success, message) {
    var response = {
        "status": success ? "success" : "error",
        "message": message
    };
    return ContentService.createTextOutput(JSON.stringify(response))
        .setMimeType(ContentService.MimeType.JSON);
}

// Getting the target page for data entry
function getTargetSheet(hook_data) {
    var spreadsheet = SpreadsheetApp.getActiveSpreadsheet();

    // Checking if the page name is specified
    if (hook_data && hook_data.sheet_name) {
        try {
            var sheet = spreadsheet.getSheetByName(hook_data.sheet_name);
            if (sheet) {
                return sheet;
            }
        } catch (error) {
            // Page not found
        }
    }

    // Checking if the page number is specified
    if (hook_data && hook_data.sheet_index && !isNaN(hook_data.sheet_index)) {
        try {
            var sheets = spreadsheet.getSheets();
            var index = parseInt(hook_data.sheet_index) - 1; // Converting to index from 0
            if (index >= 0 && index < sheets.length) {
                return sheets[index];
            }
        } catch (error) {
            // Invalid page index
        }
    }

    // By default, use the active page
    return SpreadsheetApp.getActiveSheet();
}

// Creates headers in the table based on the provided data
function populateHeaders(hook_data, sheet) {
    if (!hook_data || typeof hook_data !== 'object') {
        return false;
    }

    if (!sheet) {
        sheet = getTargetSheet(hook_data);
    }
    var last_row = Math.max(sheet.getLastRow(), 1);
    sheet.insertRowAfter(last_row);

    var headers_row = ['timestamp'];
    var hook_data_keys = Object.keys(hook_data);

    for (var i = 0; i < hook_data_keys.length; i++) {
        headers_row.push(hook_data_keys[i]);
    }

    sheet.appendRow(headers_row);
    SpreadsheetApp.flush();
    return true;
}

// Processing incoming webhook
function doPost(e) {
    var hook_load = null;

    // Checking for POST data
    if (!e || !e.postData || !e.postData.contents) {
        return sendResponse(false, "No data to process");
    }

    // Parsing JSON data
    try {
        hook_load = JSON.parse(e.postData.contents);
    } catch (error) {
        return sendResponse(false, "JSON data parsing error");
    }

    // Validation of received data
    if (!hook_load || typeof hook_load !== 'object' || Object.keys(hook_load).length === 0) {
        return sendResponse(false, "Incorrect or empty data received");
    }

    try {
        // Getting the target page
        var sheet = getTargetSheet(hook_load);
        if (!sheet) {
            return sendResponse(false, "Failed to find the specified page");
        }

        // Creating headers if the table is empty
        if (sheet.getLastColumn() === 0) {
            populateHeaders(hook_load, sheet);
        }

        var headers = sheet.getRange(1, 1, 1, sheet.getLastColumn()).getValues()[0];

        if (headers.length === 0 || headers[0] === "") {
            populateHeaders(hook_load, sheet);
            headers = sheet.getRange(1, 1, 1, sheet.getLastColumn()).getValues()[0];
        }

        // Duplicate check
        var data = [];
        var targetRow = -1;
        var numRows = sheet.getLastRow() - 1;

        if (keyColumns.length > 0 && numRows > 0) {
            data = sheet.getRange(2, 1, numRows, sheet.getLastColumn()).getValues();

            for (var r = 0; r < data.length; r++) {
                var row = data[r];
                var match = true;

                for (var k = 0; k < keyColumns.length; k++) {
                    var key = keyColumns[k];
                    var idx = headers.indexOf(key);
                    if (idx === -1 || row[idx] != hook_load[key]) {
                        match = false;
                        break;
                    }
                }

                if (match) {
                    targetRow = r + 2; // header accounting
                    break;
                }
            }
        }

        // Preparing data for entry
        var new_sheet_row = new Array(headers.length).fill('');
        for (var h = 0; h < headers.length; h++) {
            var key = headers[h];
            if (key === 'timestamp') {
                new_sheet_row[h] = new Date();
            } else if (hook_load.hasOwnProperty(key)) {
                new_sheet_row[h] = hook_load[key];
            }
        }

        // Saving data to the table
        if (targetRow > -1) {
            sheet.getRange(targetRow, 1, 1, new_sheet_row.length).setValues([new_sheet_row]);
        } else {
            sheet.appendRow(new_sheet_row);
        }

        SpreadsheetApp.flush();

        return sendResponse(true, "Data successfully saved");

    } catch (error) {
        return sendResponse(false, "Error saving data: " + error.message);
    }
}