git.scottworley.com Git - planeteer/blob - planeteer.go

   1 /* Planeteer: Give trade route advice for Planets: The Exploration of Space
   2  * Copyright (C) 2011  Scott Worley <sworley@chkno.net>
   3  *
   4  * This program is free software: you can redistribute it and/or modify
   5  * it under the terms of the GNU Affero General Public License as
   6  * published by the Free Software Foundation, either version 3 of the
   7  * License, or (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU Affero General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU Affero General Public License
  15  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  16  */
  17
  18 package main
  19
  20 import "flag"
  21 import "json"
  22 import "os"
  23 import "fmt"
  24
  25 var datafile = flag.String("planet_data_file", "planet-data",
  26         "The file to read planet data from")
  27
  28 type Commodity struct {
  29         BasePrice int
  30         CanSell   bool
  31         Limit     int
  32 }
  33 type Planet struct {
  34         Name     string
  35         BeaconOn bool
  36         /* Use relative prices rather than absolute prices because you
  37            can get relative prices without traveling to each planet. */
  38         RelativePrices map [string] int
  39 }
  40 type planet_data struct {
  41         Commodities map [string] Commodity
  42         Planets []Planet
  43 }
  44
  45 func ReadData() (data planet_data) {
  46         f, err := os.Open(*datafile)
  47         if err != nil {
  48                 panic(err)
  49         }
  50         defer f.Close()
  51         err = json.NewDecoder(f).Decode(&data)
  52         if err != nil {
  53                 panic(err)
  54         }
  55         return
  56 }
  57
  58 /* What is the value of hauling 'commodity' from 'from' to 'to'?
  59  * Take into account the available funds and the available cargo space. */
  60 func TradeValue(data planet_data,
  61                 from, to *Planet,
  62                 commodity string,
  63                 initial_funds, max_quantity int) int {
  64         if !data.Commodities[commodity].CanSell {
  65                 return 0
  66         }
  67         from_relative_price, from_available := from.RelativePrices[commodity]
  68         if !from_available {
  69                 return 0
  70         }
  71         to_relative_price, to_available := to.RelativePrices[commodity]
  72         if !to_available {
  73                 return 0
  74         }
  75
  76         base_price := data.Commodities[commodity].BasePrice
  77         from_absolute_price := from_relative_price * base_price
  78         to_absolute_price := to_relative_price * base_price
  79         buy_price := from_absolute_price
  80         sell_price := int(float64(to_absolute_price) * 0.9)
  81         var can_afford int = initial_funds / buy_price
  82         quantity := can_afford
  83         if quantity > max_quantity {
  84                 quantity = max_quantity
  85         }
  86         return (sell_price - buy_price) * max_quantity
  87 }
  88
  89 func FindBestTrades(data planet_data) [][]string {
  90         best := make([][]string, len(data.Planets))
  91         for from_index, from_planet := range data.Planets {
  92                 best[from_index] = make([]string, len(data.Planets))
  93                 for to_index, to_planet := range data.Planets {
  94                         best_gain := 0
  95                         price_list := from_planet.RelativePrices
  96                         if len(to_planet.RelativePrices) < len(from_planet.RelativePrices) {
  97                                 price_list = to_planet.RelativePrices
  98                         }
  99                         for commodity := range price_list {
 100                                 gain := TradeValue(data,
 101                                                    &from_planet,
 102                                                    &to_planet,
 103                                                    commodity,
 104                                                    10000000,
 105                                                    1)
 106                                 if gain > best_gain {
 107                                         best[from_index][to_index] = commodity
 108                                         gain = best_gain
 109                                 }
 110                         }
 111                 }
 112         }
 113         return best
 114 }
 115
 116 func main() {
 117         flag.Parse()
 118         data := ReadData()
 119         best_trades := FindBestTrades(data)
 120         for from_index, from_planet := range data.Planets {
 121                 for to_index, to_planet := range data.Planets {
 122                         best_trade := "(nothing)"
 123                         if best_trades[from_index][to_index] != "" {
 124                                 best_trade = best_trades[from_index][to_index]
 125                         }
 126                         fmt.Printf("%s to %s: %s\n", from_planet.Name, to_planet.Name, best_trade)
 127                 }
 128         }
 129 }