// NGnius 2020-01-30

package main // leadercraft-server

import (
	"flag"
	"fmt"
	"os"
	"os/signal"
)

const (
	// Version the current version
	Version = "0.1"
	// Name the program name
	Name = "leadercraft-s"
)

var (
	isClosing           bool
	printVersionAndExit bool
)

func init() {
	initArgs()
}

func main() {
	parseArgs()
	sqlInitErr := sqlInit()
	if sqlInitErr != nil {
		fmt.Printf("Failed to initialise SQL connection: %s\n", sqlInitErr)
		os.Exit(1)
	}
	// handle interrupt (terminate) signal
	signalChan := make(chan os.Signal)
	signal.Notify(signalChan, os.Interrupt)
	go func() {
		s := <-signalChan
		fmt.Println("Received terminate signal " + s.String())
		isClosing = true
		sqlClose()
	}()
	// get new rankings
	rows, err := db.Query("SELECT * FROM Entries WHERE rank=-1 ORDER BY time ASC;")
	var players []int64
	if err == nil {
		// update rank for boards
		var entries []*Entry
		count := 0
		for rows.Next() {
			entries = append(entries, &Entry{})
			scanErr := rows.Scan(entries[count].Intake()...)
			if scanErr == nil {
				//fmt.Printf("Updating rank for entry %d in board %d from player %d\n", entries[count].ID, entries[count].Board, entries[count].Player)
				if entries[count].Board > 2 { // ignore special boards
					players = append(players, entries[count].Player)
				}
				updateBoardEntries(entries[count])
				count++
			} else {
				fmt.Println(scanErr)
			}
		}
		// update special boards
		for _, elem := range players {
			p := &Player{ID: elem}
			err := p.Load()
			if err == nil {
				//fmt.Printf("Updating high score for player %d\n", p.ID)
				updateMainRank(p)
			} else {
				fmt.Println(err)
			}
		}
	} else {
		fmt.Println(err)
	}
}

func initArgs() {
	flag.BoolVar(&printVersionAndExit, "version", false, "Print version and exit")
	flag.StringVar(&sqlConnection, "conn", sqlConnectionDefault, "Database connection string")
	flag.StringVar(&sqlServer, "sql", sqlServerDefault, "SQL Database type")
}

func parseArgs() {
	flag.Parse()
	if printVersionAndExit {
		fmt.Println(Name + " v" + Version)
		os.Exit(0)
	}
}

func updateBoardEntries(entry *Entry) {
	// get nearest entry that's lower and steal it's rank
	nearestEntry := &Entry{}
	scanErr := db.QueryRow("SELECT * FROM Entries WHERE score < $1 AND rank!= -1 AND board=$2 ORDER BY score DESC LIMIT 1;", entry.Score, entry.Board).Scan(nearestEntry.Intake()...)
	if scanErr == nil {
		entry.Rank = nearestEntry.Rank
		entry.Commit()
		// update all ranks lower than itself
		tx, _ := db.Begin()
		stmt, _ := tx.Prepare("UPDATE Entries SET rank=rank+1 WHERE rank >=$1 AND id!=$2 AND board=$3;")
		_, err := stmt.Exec(entry.Rank, entry.ID, entry.Board)
		if err != nil {
			tx.Rollback()
			fmt.Println(err)
		} else {
			tx.Commit()
		}
	} else {
		// nothing to beat
		scanErr = db.QueryRow("SELECT * FROM Entries WHERE score >= $1 AND rank!= -1 AND board=$2 ORDER BY score ASC LIMIT 1;", entry.Score, entry.Board).Scan(nearestEntry.Intake()...)
		if scanErr == nil {
			entry.Rank = nearestEntry.Rank + 1
			entry.Commit()
		} else {
			// no other entries
			entry.Rank = 1
			entry.Commit()
		}
	}
}

func updateMainRank(p *Player) {
	rows, err := db.Query("SELECT * FROM Entries WHERE player = $1 AND board > 2 ORDER BY score DESC LIMIT $2;", p.ID, 100)
	var count int64 = 0
	var sum int64 = 0
	if err == nil {
		for rows.Next() {
			entry := &Entry{}
			scanErr := rows.Scan(entry.Intake()...)
			if scanErr == nil {
				count++
				sum += entry.Score
			} else {
				fmt.Println(scanErr)
				return
			}
		}
		if count > 0 && sum > 0 {
			mainEntry := &Entry{
				Player: p.ID,
				Board:  1,
			}
			average := sum / count
			//fmt.Printf("Average of %d/%d is %d\n", sum, count, average)
			dne := db.QueryRow("SELECT * FROM Entries WHERE board=$1 AND player=$2", 1, p.ID).Scan(mainEntry.Intake()...)
			if dne == nil {
				tx, _ := db.Begin()
				stmt, _ := tx.Prepare("UPDATE Entries SET rank=rank-1 WHERE rank >$1 AND id!=$2 AND board=$3;")
				_, err := stmt.Exec(mainEntry.Rank, mainEntry.ID, 1)
				if err != nil {
					tx.Rollback()
					fmt.Println(err)
					return // abort
				} else {
					tx.Commit()
				}
				mainEntry.Score = average
				mainEntry.Rank = -1
				mainEntry.Commit()
			} else {
				createErr := newEntrySql(average, p.ID, 1)
				if createErr == nil {
					fmt.Println(createErr)
					return
				}
			}
		}
	} else {
		fmt.Println(err)
		return
	}
}