import jwt from "jsonwebtoken";
import { VAModel, ProjectModel, LoggedModel } from "../../../models/vaModel.js";

// Helper function to parse date string in DD-MM-YYYY format
function parseDate(dateString) {
    if (!dateString) return null;
    
    const parts = dateString.split('-');
    if (parts.length !== 3) return null;
    
    const day = parseInt(parts[0], 10);
    const month = parseInt(parts[1], 10) - 1; // Months are 0-indexed in JavaScript
    const year = parseInt(parts[2], 10);
    
    // Validate date components
    if (isNaN(day) || isNaN(month) || isNaN(year)) return null;
    if (day < 1 || day > 31 || month < 0 || month > 11 || year < 1900) return null;
    
    return new Date(year, month, day);
}

// Getting logged hours in a specific project of VA
async function va_log_work_report_callback(req, res) {
    try {
        const accessToken = req.headers.token;        
        
        if (!accessToken) {
            return res.status(401).json({ success: false, message: "Missing token" });
        }

        const decoded = jwt.verify(accessToken, process.env.JWT_SECRET_ACCESS_TOKEN);

        if (!decoded || !decoded.email) {
            return res.status(401).json({ success: false, message: "Invalid token" });
        }

        const vaEmail = decoded.email;
        const vaUser = await VAModel.findOne({ "userDetails.email": vaEmail });
        if (!vaUser) {
            return res.status(404).json({ success: false, message: "VA not found" });
        }

        const vaId = vaUser._id;
        
        const payload = req.body || {};
        const { fromDate, toDate } = payload;

        let start = fromDate ? parseDate(fromDate) : new Date();
        let end = toDate ? parseDate(toDate) : new Date();

        if ((fromDate && (!start || isNaN(start.getTime()))) || (toDate && (!end || isNaN(end.getTime())))) {
            return res.status(400).json({ 
                success: false, 
                message: "Invalid Date format. Use DD-MM-YYYY" 
            });
        }

        if (!fromDate && !toDate) {
            // If no dates provided, default to today
            start.setHours(0, 0, 0, 0);
            end.setHours(23, 59, 59, 999);
        } else {
            // If dates are provided, set proper time boundaries
            if (fromDate) start.setHours(0, 0, 0, 0);
            if (toDate) end.setHours(23, 59, 59, 999);
        }

        let logs = await LoggedModel.find({
            vaId,
            time: { $gte: start, $lte: end },
        })
            .sort({ time: 1 })
            .populate("projectId", "name") // attach project name
            .lean();

        if (!logs.length) {
            return res.status(200).json({
                success: true,
                message: "No logs found in given range",
                data: [],
                totalWorkTime: "00:00:00",
            });
        }

        let totalWorkSeconds = 0;
        const projectWork = {}; // key: projectId -> seconds

        // Group logs by date (YYYY-MM-DD format)
        const logsByDate = {};
        logs.forEach(log => {
            const date = new Date(log.time).toISOString().split('T')[0]; // YYYY-MM-DD
            if (!logsByDate[date]) {
                logsByDate[date] = [];
            }
            logsByDate[date].push(log);
        });

        // Process each day separately
        for (const [date, dayLogs] of Object.entries(logsByDate)) {
            // Check if this day has any adjustment logs
            const hasAdjustmentLogs = dayLogs.some(log => log.isAdjustment === true);
            
            let dayWorkSeconds = 0;
            let lastLogin = null;
            let lastProjectId = null;

            // If day has adjustment logs, only process adjustment logs
            // If no adjustment logs, process all logs for that day
            const logsToProcess = hasAdjustmentLogs 
                ? dayLogs.filter(log => log.isAdjustment === true)
                : dayLogs;

            // Sort logs by time for proper pairing (already sorted by query, but ensure)
            logsToProcess.sort((a, b) => new Date(a.time) - new Date(b.time));

            // Calculate work duration for this day
            for (const log of logsToProcess) {
                const time = new Date(log.time);

                if (log.loggedType === "LOGIN") {
                    lastLogin = time;
                    lastProjectId = log.projectId?._id?.toString() || null;
                } else if (log.loggedType === "LOGOUT" && lastLogin) {
                    const diffSec = (time - lastLogin) / 1000;
                    dayWorkSeconds += diffSec;

                    if (lastProjectId) {
                        projectWork[lastProjectId] = (projectWork[lastProjectId] || 0) + diffSec;
                    }

                    // reset after each pair
                    lastLogin = null;
                    lastProjectId = null;
                }
            }

            totalWorkSeconds += dayWorkSeconds;
        }

        // 🕓 Convert total seconds to hh:mm:ss
        const formatTime = (seconds) => {
            const h = Math.floor(seconds / 3600);
            const m = Math.floor((seconds % 3600) / 60);
            const s = Math.floor(seconds % 60);
            return `${h.toString().padStart(2, "0")}:${m.toString().padStart(2, "0")}:${s.toString().padStart(2, "0")}`;
        };

        // 🧠 Build project-wise array
        const projectDetails = await Promise.all(
            Object.entries(projectWork).map(async ([projectId, sec]) => {
                const project = await ProjectModel.findById(projectId).lean();
                return {
                    projectId,
                    projectName: project?.name || "Unknown Project",
                    totalTime: formatTime(sec),
                };
            })
        );

        return res.status(200).json({
            success: true,
            from: start,
            to: end,
            totalWorkTime: formatTime(totalWorkSeconds),
            projects: projectDetails,
            logs, // optional raw logs for debugging
        });
        
    } catch (error) {
        console.log(error)
        return res.status(500).send("Internal Server Error");
    }
}

export { va_log_work_report_callback };