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116 lines
2.1 KiB
Go

package main
import (
"database/sql"
"fmt"
"math"
"math/rand"
)
var (
index map[int]*System
)
type System struct {
x, y, z float64
planets int
name string
players map[*Connection]bool
}
func (s *System) Arrive(p *Connection) {
log_info("player %s has arrived at system %s", p.PlayerName(), s.name)
if s.players == nil {
s.players = make(map[*Connection]bool, 8)
}
s.players[p] = true
}
func (s *System) Leave(p *Connection) {
delete(s.players, p)
}
func (s *System) EachConn(fn func(*Connection)) {
if s.players == nil {
return
}
for conn, _ := range s.players {
fn(conn)
}
}
func (s *System) NumInhabitants() int {
if s.players == nil {
return 0
}
return len(s.players)
}
func (e System) Store(db *sql.DB) {
_, err := db.Exec(`
insert into planets
(name, x, y, z, planets)
values
(?, ?, ?, ?, ?)
;`, e.name, e.x, e.y, e.z, e.planets)
if err != nil {
log_error("%v", err)
}
}
func (e System) String() string {
return fmt.Sprintf("<name: %s x: %v y: %v z: %v planets: %v>", e.name, e.x, e.y, e.z, e.planets)
}
func countPlanets() (int, error) {
row := db.QueryRow(`select count(*) from planets`)
var n int
err := row.Scan(&n)
return n, err
}
func sq(x float64) float64 {
return x * x
}
func dist3d(x1, y1, z1, x2, y2, z2 float64) float64 {
return math.Sqrt(sq(x1-x2) + sq(y1-y2) + sq(z1-z2))
}
func planetDistance(p1, p2 System) float64 {
return dist3d(p1.x, p1.y, p1.z, p2.x, p2.y, p2.z)
}
func indexPlanets(db *sql.DB) map[int]*System {
rows, err := db.Query(`select * from planets`)
if err != nil {
log_error("unable to select all planets: %v", err)
return nil
}
defer rows.Close()
index = make(map[int]*System, 551)
for rows.Next() {
var id int
p := System{}
if err := rows.Scan(&id, &p.name, &p.x, &p.y, &p.z, &p.planets); err != nil {
log_info("unable to scan planet row: %v", err)
continue
}
index[id] = &p
}
return index
}
func randomPlanet() (*System, error) {
n := len(index)
if n == 0 {
return nil, fmt.Errorf("no planets are known to exist")
}
pick := rand.Intn(n)
planet := index[pick]
return planet, nil
}