BusScheduler.cpp

#include "BusScheduler.h"
#include "common.h"
#include "DataLoader.h"
#include <iostream>
#include <map>
#include <vector>
#include <iomanip>
#include <stdexcept>

BusScheduler::BusScheduler(RouteGraph *graph)
{
    // Store a pointer to the graph to get travel times
    this->routeGraph = graph;
}

// Adds a single scheduled bus departure to the system.
void BusScheduler::addScheduledBus(string busNum, string startStop, int depTime)
{
    string normStop = normalizeString(startStop);
    // Add to the priority queue for that specific stop
    allSchedules[normStop].push({busNum, normStop, depTime});
}

// Takes an "optimal" path (from RouteGraph) and a user's start time,
// and calculates the "actual" journey, including wait times and fare.
JourneyPlan BusScheduler::findJourney(RoutePlan &plan, int userStartTime)
{
    JourneyPlan journey;
    int currentTime = userStartTime; // acts as the clock

    journey.totalFare = 0.0;
    // Go through the optimal path step-by-step
    for (const auto &step : plan.steps)
    {
        // 1. Find the next bus for this leg
        ScheduledBus nextBus = findNextAvailableBus(step.busNumber, step.startStop, currentTime);
        // 2. Check if a bus was found
        if (nextBus.departureTime == -1)
        {
            cout << "\nError: No available bus found for the leg: "
                 << step.startStop << " to " << step.endStop
                 << " (Bus " << step.busNumber << ") at or after "
                 << minutesToTime(currentTime) << "." << endl;

            journey.finalArrivalTime = -1; // Mark journey as invalid
            return journey;
        }
        // 3. A bus was found! Update our journey
        JourneyStep journeyStep;
        journeyStep.startStop = step.startStop;
        journeyStep.endStop = step.endStop;
        journeyStep.busNumber = step.busNumber;
        journeyStep.departureTime = nextBus.departureTime;
        journeyStep.arrivalTime = nextBus.departureTime + step.time;
        journeyStep.waitTime = nextBus.departureTime - currentTime;
        journeyStep.travelTime = step.time;
        journey.steps.push_back(journeyStep);
        // 4. Update our "clock" for the next leg
        currentTime = journeyStep.arrivalTime;
        // 5. Update total times
        journey.totalTravelTime += step.time;
        journey.totalWaitTime += journeyStep.waitTime;
        // 6. Calculate Fare
        try
        {
            // Get the normalized bus number (e.g., "21g")
            string normBus = normalizeString(step.busNumber);
            // Get the fare rate from the static map
            double rate = DataLoader::busFareRates.at(normBus);
            double stepFare = journeyStep.travelTime * rate;
            journey.totalFare += stepFare;
        }
        catch (const out_of_range &e)
        {
            cout << "Warning: No fare rate found for bus " << step.busNumber
                 << ". Using default rate of 1.5." << endl;
            journey.totalFare += (journeyStep.travelTime * 1.5); // Default rate
        }
    }

    journey.finalArrivalTime = currentTime;
    return journey;
}

// Prints a formatted journey plan to the console, including fare.
void BusScheduler::printJourneyPlan(JourneyPlan &plan)
{
    if (plan.finalArrivalTime == -1)
    {
        // findJourney function prints the error
        return;
    }
    cout << fixed << setprecision(2);

    cout << "\n--- Your Journey Plan ---" << endl;
    for (const auto &step : plan.steps)
    {
        cout << "\n  [STEP]: " << step.startStop << " to " << step.endStop << endl;
        cout << "  > Take Bus:    " << step.busNumber << endl;
        if (step.waitTime > 0)
        {
            cout << "  > Wait Time:   " << step.waitTime << " minutes" << endl;
        }
        cout << "  > Depart at:   " << minutesToTime(step.departureTime) << endl;
        cout << "  > Arrive at:   " << minutesToTime(step.arrivalTime) << endl;
        cout << "  (Travel time for this leg: " << step.travelTime << " min)" << endl;
    }
    cout << "\n--- Summary ---" << endl;
    cout << "Final Destination Reached at: " << minutesToTime(plan.finalArrivalTime) << endl;
    cout << "Total Time on Bus: " << plan.totalTravelTime << " minutes" << endl;
    cout << "Total Time Waiting: " << plan.totalWaitTime << " minutes" << endl;
    cout << "Total Journey Time: " << (plan.totalTravelTime + plan.totalWaitTime) << " minutes" << endl;
    cout << "Estimated Total Fare: Rs. " << plan.totalFare << endl;
    cout << "-------------------------" << endl;

    cout.unsetf(ios_base::floatfield);
}

// Finds the earliest bus for a specific route leg that departs
ScheduledBus BusScheduler::findNextAvailableBus(string busNum, string stop, int afterTime)
{
    string normStop = normalizeString(stop);
    string normBus = normalizeString(busNum);

    // 1. Check if this stop exists in our schedule map
    if (allSchedules.find(normStop) == allSchedules.end())
    {
        return {"", "", -1}; // No buses ever from this stop
    }

    // 2. Get the priority queue for this stop
    // make a copy so we can search without removing buses from the real schedule
    priority_queue<ScheduledBus, vector<ScheduledBus>, greater<ScheduledBus>> tempQueue = allSchedules[normStop];

    // 3. Search the queue
    while (!tempQueue.empty())
    {
        ScheduledBus bus = tempQueue.top();
        tempQueue.pop(); // Check the next bus

        // Check 1: Does the bus number match?
        // Check 2: Does it depart at or after the time we need?
        if (normalizeString(bus.busNumber) == normBus && bus.departureTime >= afterTime)
        {
            return bus; // best bus found.
        }
    }

    // 4. No bus found
    return {"", "", -1};
}