package airport

import (
	"fmt"
	"math/rand"
	"strings"
	"time"
)

type FlightNumber string

type Flight struct {
	Id            FlightNumber
	Destination   string
	GateNumber    GateNumber
	BoardingTime  time.Time
	DepartureTime time.Time
}

type FlightProvider interface {
	GetFlight(FlightNumber) (Flight, error)
}

type FlightSchedule struct {
	flights map[FlightNumber]Flight
}

var possibleDestinations = []string{
	"AMS", "ATH", "BCN", "BRU", "BUD", "CPH", "DUB", "DUS", "EDI", "FCO",
	"FRA", "GVA", "HEL", "IST", "LIS", "LYS", "MAD", "MUC", "OSL", "PRG",
	"RIX", "SOF", "STO", "TLL", "VIE", "WAW", "ZAG", "ZRH", "LUX", "MLA",
}

func GenerateRandomFlightNumbers(count int) []FlightNumber {

	airlines := []string{"LH", "AF", "KL", "BA", "SK", "AZ", "IB", "TK", "AY", "OS"}
	flightNumbers := make([]FlightNumber, count)

	for i := 0; i < count; i++ {
		airline := airlines[rand.Intn(len(airlines))]
		number := rand.Intn(9000) + 1000 // Random 4-digit number
		flightNumbers[i] = FlightNumber(fmt.Sprintf("%s%04d", airline, number))
	}

	return flightNumbers
}

func GenerateRandomFlightSchedule(gates map[GateNumber]*Gate, count int) FlightSchedule {
	flightNumbers := GenerateRandomFlightNumbers(count)
	flights := make(map[FlightNumber]Flight)

	gateNumbers := make([]GateNumber, 0, len(gates))
	for gn, _ := range gates {
		gateNumbers = append(gateNumbers, gn)
	}

	for _, flightNumber := range flightNumbers {
		destination := possibleDestinations[rand.Intn(len(possibleDestinations))]

		gateNumber := gateNumbers[rand.Intn(len(gateNumbers))]
		departureTime := time.Now().Add(time.Duration(rand.Intn(5*60)) * time.Second)
		boardingTime := departureTime.Add(-30 * time.Second)

		flights[flightNumber] = Flight{
			Id:            flightNumber,
			Destination:   destination,
			GateNumber:    gateNumber,
			BoardingTime:  boardingTime,
			DepartureTime: departureTime,
		}
	}

	return FlightSchedule{flights: flights}
}

func (fs *FlightSchedule) AllFlights() []Flight {
	flights := make([]Flight, 0, len(fs.flights))
	for _, flight := range fs.flights {
		flights = append(flights, flight)
	}
	return flights
}

func (fs *FlightSchedule) GetFlight(flightNumber FlightNumber) (Flight, error) {
	if flight, ok := fs.flights[flightNumber]; ok {
		return flight, nil
	} else {
		return Flight{}, fmt.Errorf("invalid flight number %v", flightNumber)
	}
}

func (fs *FlightSchedule) Print() {
	fmt.Printf("%-15s %-15s %-10s %-20s %-20s\n", "Flight Number", "Destination", "Gate", "Boarding Time", "Departure Time")
	fmt.Println(strings.Repeat("-", 80))
	for _, flight := range fs.AllFlights() {
		fmt.Printf("%-15s %-15s %-10d %-20s %-20s\n",
			flight.Id,
			flight.Destination,
			flight.GateNumber,
			flight.BoardingTime.Format("15:04:05"),
			flight.DepartureTime.Format("15:04:05"),
		)
	}
}