API Endpoints

function doGet() {
    const sheet = getTargetSheet();
    const data = sheet.getDataRange().getValues();
    const balance = calculateBalance(sheet);
    const budget = SCRIPT_PROP.getProperty("DAILY_BUDGET") || 350;
    const privacyRaw = SCRIPT_PROP.getProperty("PRIVACY_MODE");
    const privacy = privacyRaw === null ? true : (privacyRaw === "true");

    const expenses = [];
    const startRow = Math.max(1, data.length - 50);
    for (let i = startRow; i < data.length; i++) {
        if (data[i][0]) {
            expenses.push({
                date: data[i][0],
                description: data[i][1],
                amount: data[i][2],
                category: data[i][3],
                type: data[i][4]
            });
        }
    }

    return ContentService.createTextOutput(JSON.stringify({
        balance: balance,
        expenses: expenses,
        budget: budget,
        privacy: privacy
    })).setMimeType(ContentService.MimeType.JSON);
}

if (body.action === "process_text") {
    const userText = body.text;
    const mode = body.mode; // 'add' or 'ask'
    
    // Fetches last 40 transactions for context
    const historyData = sheet.getRange(
        Math.max(1, sheet.getLastRow() - 40), 1, 41, 4
    ).getValues();
    
    // Sends to Gemini Flash API with context
    const aiUrl = `https://generativelanguage.googleapis.com/v1beta/models/gemini-flash-latest:generateContent?key=${geminiKey}`;
    
    // Returns parsed transaction or answer
}

if (body.action === "add") {
    const date = new Date();
    const type = (body.type === 'income' || body.category === 'Income') 
        ? 'CREDIT' : 'DEBIT';
    sheet.appendRow([date, body.description, body.amount, body.category, type]);
    const newBalance = calculateBalance(sheet);
    
    return ContentService.createTextOutput(JSON.stringify({
        status: "Success",
        balance: newBalance,
        parsed: { date, description: body.description, amount: body.amount, category: body.category, type }
    })).setMimeType(ContentService.MimeType.JSON);
}

if (body.action === "delete") {
    const data = sheet.getDataRange().getValues();
    // Search from bottom to top (most recent first)
    for (let i = data.length - 1; i >= 0; i--) {
        if (data[i][1] === body.description && data[i][2] == body.amount) {
            sheet.deleteRow(i + 1);
            const newBalance = calculateBalance(sheet);
            return ContentService.createTextOutput(JSON.stringify({
                status: "Deleted",
                balance: newBalance
            })).setMimeType(ContentService.MimeType.JSON);
        }
    }
    return ContentService.createTextOutput(JSON.stringify({ 
        status: "Not Found" 
    })).setMimeType(ContentService.MimeType.JSON);
}

if (body.action === "save_settings") {
    SCRIPT_PROP.setProperty("DAILY_BUDGET", body.budget.toString());
    SCRIPT_PROP.setProperty("PRIVACY_MODE", body.privacy.toString());
    if (body.geminiKey) SCRIPT_PROP.setProperty("GEMINI_KEY", body.geminiKey);
    return ContentService.createTextOutput(JSON.stringify({ 
        status: "Saved" 
    })).setMimeType(ContentService.MimeType.JSON);
}

function calculateBalance(sheet) {
    const data = sheet.getDataRange().getValues();
    let bal = 0;
    // Start from row 1 to skip header
    for (let i = 1; i < data.length; i++) {
        const amount = parseFloat(data[i][2]); // Column C
        const type = data[i][4]; // Column E
        
        if (!isNaN(amount)) {
            if (type === 'CREDIT') {
                bal += amount;
            } else {
                bal -= amount; // DEBIT or blank
            }
        }
    }
    return bal;
}

function getTargetSheet() {
    const ss = SpreadsheetApp.openById(SHEET_ID);
    return ss.getSheets()[0];
}

You are a financial assistant. 
CONTEXT: The user wants to ADD a transaction.
USER INPUT: "{userText}"
HISTORY: {last 40 transactions}

TASK:
1. Extract: Description, Amount, Category (Food, Transport, Tech, Invest, Income, Misc).
2. Analyze: Compare this new expense to the HISTORY. Is it higher than usual? Is it a repeat?
3. Insight: Write a very short, witty, or helpful insight (max 15 words) about this specific spend.

OUTPUT JSON STRICTLY:
{
  "description": "String",
  "amount": Number,
  "category": "String",
  "type": "DEBIT" or "CREDIT",
  "insight": "String"
}

You are a financial analyst.
CONTEXT: The user is ASKING a question about their finances.
USER INPUT: "{userText}"
HISTORY: {last 40 transactions}

TASK: 
Answer the user's question based strictly on the HISTORY data provided. 
Be concise (max 30 words).

OUTPUT JSON STRICTLY:
{
  "answer": "String"
}