package csv

import (
	"encoding/csv"
	"errors"
	"fmt"
	"log"
	"os"
	"regexp"
	"strings"
	"sync"
	"time"

	"airlines/pkg/airports"
	"airlines/pkg/model"
	"airlines/pkg/names"

	"github.com/schollz/progressbar/v3"
)

type csvData struct {
	data                [][]string
	ignoreNonLatinUsers bool
}

func UnmarshallCsv(filePath string, ignoreNonLatinUsers bool) (*csvData, error) {
	d := &csvData{ignoreNonLatinUsers: ignoreNonLatinUsers}

	f, err := os.Open(filePath)
	if err != nil {
		return nil, err
	}
	defer f.Close()

	csvReader := csv.NewReader(f)
	d.data, err = csvReader.ReadAll()
	if err != nil {
		log.Fatal("Unable to parse file as CSV for "+filePath, err)
	}

	return d, nil
}

func createUser(cols map[string]int, data []string) (*model.User, error) {
	fio, err := names.ParseLatinName(data[cols["PaxName"]])
	if err != nil {
		return nil, errors.New(data[cols["PaxName"]] + ":" + err.Error())
	}

	var bdayDate time.Time
	bday := strings.TrimSpace(data[cols["PaxBirthDate"]]) // "YYYY-MM-DD"
	if bday == "" {
		bdayDate = model.SentinelBirthday()
	} else {
		bdayDate, err = time.Parse("2006-01-02", bday)
		if err != nil {
			return nil, fmt.Errorf("bad birthday %q: %w", bday, err)
		}
	}

	u := &model.User{
		Name:        strings.ToUpper(fio.First),
		Surname:     strings.ToUpper(fio.Last),
		Fathersname: strings.ToUpper(fio.Patronymic),
		Birthday:    bdayDate,
	}
	return u, nil
}

func createCard(cols map[string]int, data []string) (*model.Card, error) {
	prefix, number, _ := model.ParseCardLine(data[cols["CardNumber"]])
	if prefix == "" && number == 0 {
		return nil, errors.New("bad card id")
	}

	return &model.Card{
		Prefix: prefix,
		Number: number,
	}, nil
}

var hhmm = regexp.MustCompile(`^\d{2}:\d{2}$`)

func NormalizeTime(s string) string {
	if hhmm.MatchString(s) {
		h := (int(s[0]-'0')*10 + int(s[1]-'0'))
		m := (int(s[3]-'0')*10 + int(s[4]-'0'))
		if h < 24 && m < 60 {
			return s
		}
		return ""
	}

	digits := make([]byte, 0, 4)
	for i := 0; i < len(s); i++ {
		c := s[i]
		if c >= '0' && c <= '9' {
			digits = append(digits, c)
		} else if c == ':' {
			continue
		} else {
			return ""
		}
	}

	if len(digits) == 3 {
		h := int(digits[0] - '0')
		m := int(digits[1]-'0')*10 + int(digits[2]-'0')
		if h < 24 && m < 60 {
			return fmt.Sprintf("%02d:%02d", h, m)
		}
		return ""
	}

	if len(digits) == 4 {
		h := int(digits[0]-'0')*10 + int(digits[1]-'0')
		m := int(digits[2]-'0')*10 + int(digits[3]-'0')
		if h < 24 && m < 60 {
			return fmt.Sprintf("%02d:%02d", h, m)
		}
		return ""
	}

	return ""
}

func createFlight(cols map[string]int, data []string) (*model.Flight, error) {
	f := &model.Flight{}

	f.From = strings.TrimSpace(data[cols["From"]])
	f.To = strings.TrimSpace(data[cols["Dest"]])
	f.Number = strings.TrimSpace(data[cols["FlightCodeSh"]])
	f.Code = strings.TrimSpace(data[cols["Code"]])

	d, err := time.Parse("2006-01-02 15:04", strings.TrimSpace(data[cols["DepartDate"]])+" "+NormalizeTime(strings.TrimSpace(data[cols["DepartTime"]])))
	if err != nil {
		return nil, fmt.Errorf("invalid Date %q: %w", strings.TrimSpace(data[cols["DepartDate"]])+" "+NormalizeTime(strings.TrimSpace(data[cols["DepartTime"]])), err)
	}

	ap, _ := airports.LookupIATA(f.From)
	f.FromCoords.Lat = ap.Latitude
	f.FromCoords.Long = ap.Longitude

	loc := model.TzFromAirportRecord(ap)
	departLocal := time.Date(d.Year(), d.Month(), d.Day(), d.Hour(), d.Minute(), 0, 0, loc)
	f.Date = departLocal.UTC()
	f.HasTime = strings.TrimSpace(data[cols["DepartTime"]]) != ""

	ap, _ = airports.LookupIATA(f.To)
	f.ToCoords.Lat = ap.Latitude
	f.ToCoords.Long = ap.Longitude

	return f, nil
}

func (dat *csvData) DumpToDb(store model.Store) {
	bar := progressbar.Default(int64(len(dat.data)-1), "dumping csv data")

	cols := map[string]int{}

	for i, col := range dat.data[0] {
		cols[col] = i
	}

	var wg sync.WaitGroup
	sem := make(chan struct{}, 8)

	for i := 1; i < len(dat.data); i++ {
		sem <- struct{}{}
		wg.Add(1)
		go func() {
			defer func() { <-sem }()
			defer wg.Done()
			defer bar.Add(1)

			var u *model.User
			var err error
			if dat.ignoreNonLatinUsers {
				goto skipUser
			}
			u, err = createUser(cols, dat.data[i])
			if err != nil {
				fmt.Println(err)
				// return
			}
			u, err = store.SaveUser(u)
			if err != nil {
				fmt.Println(err)
				// return
			}
		skipUser:

			c, err := createCard(cols, dat.data[i])
			if err != nil {
				// fmt.Println(err)
				// return
			}
			if c != nil {
				if u != nil {
					c.UserID = u.ID
				}
				c, err = store.SaveCard(c)
				if err != nil {
					// fmt.Println(err)
					// return
				}
			}

			f, err := createFlight(cols, dat.data[i])
			if err != nil {
				fmt.Println(err)
				return
			}
			if f != nil {
				if u != nil {
					f.UserID = u.ID
				}
				if c != nil {
					f.CardID = c.ID
				}

				_, err = store.SaveFlight(f)
				if err != nil {
					fmt.Println(err)
					// return
				}
			}
		}()

	}

}