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 "fmt"
  22 import "json"
  23 import "os"
  24 import "strings"
  25
  26 var start = flag.String("start", "",
  27         "The planet to start at")
  28
  29 var end = flag.String("end", "",
  30         "A comma-separated list of acceptable ending planets.")
  31
  32 var planet_data_file = flag.String("planet_data_file", "planet-data",
  33         "The file to read planet data from")
  34
  35 var fuel = flag.Int("fuel", 16, "Reactor units")
  36
  37 var hold = flag.Int("hold", 300, "Size of your cargo hold")
  38
  39 var start_edens = flag.Int("start_edens", 0,
  40         "How many Eden Warp Units are you starting with?")
  41
  42 var end_edens = flag.Int("end_edens", 0,
  43         "How many Eden Warp Units would you like to keep (not use)?")
  44
  45 var cloak = flag.Bool("cloak", false,
  46         "Make sure to end with a Device of Cloaking")
  47
  48 var drones = flag.Int("drones", 0, "Buy this many Fighter Drones")
  49
  50 var batteries = flag.Int("batteries", 0, "Buy this many Shield Batterys")
  51
  52 var visit_string = flag.String("visit", "",
  53         "A comma-separated list of planets to make sure to visit")
  54
  55 func visit() []string {
  56         return strings.Split(*visit_string, ",")
  57 }
  58
  59 type Commodity struct {
  60         BasePrice int
  61         CanSell   bool
  62         Limit     int
  63 }
  64 type Planet struct {
  65         BeaconOn bool
  66         /* Use relative prices rather than absolute prices because you
  67            can get relative prices without traveling to each planet. */
  68         RelativePrices map[string]int
  69 }
  70 type planet_data struct {
  71         Commodities map[string]Commodity
  72         Planets     map[string]Planet
  73         pi, ci      map[string]int // Generated; not read from file
  74 }
  75
  76 func ReadData() (data planet_data) {
  77         f, err := os.Open(*planet_data_file)
  78         if err != nil {
  79                 panic(err)
  80         }
  81         defer f.Close()
  82         err = json.NewDecoder(f).Decode(&data)
  83         if err != nil {
  84                 panic(err)
  85         }
  86         return
  87 }
  88
  89 /* This program operates by filling in a state table representing the best
  90  * possible trips you could make; the ones that makes you the most money.
  91  * This is feasible because we don't look at all the possible trips.
  92  * We define a list of things that are germane to this game and then only
  93  * consider the best outcome in each possible game state.
  94  *
  95  * Each cell in the table represents a state in the game.  In each cell,
  96  * we track two things: 1. the most money you could possibly have while in
  97  * that state and 2. one possible way to get into that state with that
  98  * amount of money.
  99  *
 100  * A basic analysis can be done with a two-dimensional table: location and
 101  * fuel.  planeteer-1.0 used this two-dimensional table.  This version
 102  * adds features mostly by adding dimensions to this table.
 103  *
 104  * Note that the sizes of each dimension are data driven.  Many dimensions
 105  * collapse to one possible value (ie, disappear) if the corresponding
 106  * feature is not enabled.
 107  */
 108
 109 // The official list of dimensions:
 110 const (
 111         // Name                Num  Size  Description
 112         Edens        = iota //   1     3  # of Eden warp units (0 - 2 typically)
 113         Cloaks              //   2     2  # of Devices of Cloaking (0 or 1)
 114         UnusedCargo         //   3     4  # of unused cargo spaces (0 - 3 typically)
 115         Fuel                //   4    17  Reactor power left (0 - 16)
 116         Location            //   5    26  Location (which planet)
 117         Hold                //   6    15  Cargo bay contents (a *Commodity or nil)
 118         NeedFighters        //   7     2  Errand: Buy fighter drones (needed or not)
 119         NeedShields         //   8     2  Errand: Buy shield batteries (needed or not)
 120         Visit               //   9  2**N  Visit: Stop by these N planets in the route
 121
 122         NumDimensions
 123 )
 124
 125 func bint(b bool) int {
 126         if b {
 127                 return 1
 128         }
 129         return 0
 130 }
 131
 132 func DimensionSizes(data planet_data) []int {
 133         eden_capacity := data.Commodities["Eden Warp Units"].Limit
 134         cloak_capacity := bint(*cloak)
 135         dims := []int{
 136                 eden_capacity + 1,
 137                 cloak_capacity + 1,
 138                 eden_capacity + cloak_capacity + 1,
 139                 *fuel + 1,
 140                 len(data.Planets),
 141                 len(data.Commodities),
 142                 bint(*drones > 0) + 1,
 143                 bint(*batteries > 0) + 1,
 144                 1 << uint(len(visit())),
 145         }
 146         if len(dims) != NumDimensions {
 147                 panic("Dimensionality mismatch")
 148         }
 149         return dims
 150 }
 151
 152 func StateTableSize(dims []int) int {
 153         sum := 0
 154         for _, size := range dims {
 155                 sum += size
 156         }
 157         return sum
 158 }
 159
 160 type State struct {
 161         funds, from int
 162 }
 163
 164 func NewStateTable(dims []int) []State {
 165         return make([]State, StateTableSize(dims))
 166 }
 167
 168 func EncodeIndex(dims, addr []int) int {
 169         index := addr[0]
 170         for i := 1; i < len(dims); i++ {
 171                 index = index*dims[i] + addr[i]
 172         }
 173         return index
 174 }
 175
 176 func DecodeIndex(dims []int, index int) []int {
 177         addr := make([]int, len(dims))
 178         for i := len(dims) - 1; i > 0; i-- {
 179                 addr[i] = index % dims[i]
 180                 index /= dims[i]
 181         }
 182         addr[0] = index
 183         return addr
 184 }
 185
 186 /* What is the value of hauling 'commodity' from 'from' to 'to'?
 187  * Take into account the available funds and the available cargo space. */
 188 func TradeValue(data planet_data,
 189 from, to Planet,
 190 commodity string,
 191 initial_funds, max_quantity int) int {
 192         if !data.Commodities[commodity].CanSell {
 193                 return 0
 194         }
 195         from_relative_price, from_available := from.RelativePrices[commodity]
 196         if !from_available {
 197                 return 0
 198         }
 199         to_relative_price, to_available := to.RelativePrices[commodity]
 200         if !to_available {
 201                 return 0
 202         }
 203
 204         base_price := data.Commodities[commodity].BasePrice
 205         from_absolute_price := from_relative_price * base_price
 206         to_absolute_price := to_relative_price * base_price
 207         buy_price := from_absolute_price
 208         sell_price := int(float64(to_absolute_price) * 0.9)
 209         var can_afford int = initial_funds / buy_price
 210         quantity := can_afford
 211         if quantity > max_quantity {
 212                 quantity = max_quantity
 213         }
 214         return (sell_price - buy_price) * max_quantity
 215 }
 216
 217 func FindBestTrades(data planet_data) [][]string {
 218         // TODO: We can't cache this because this can change based on available funds.
 219         best := make([][]string, len(data.Planets))
 220         for from := range data.Planets {
 221                 best[data.pi[from]] = make([]string, len(data.Planets))
 222                 for to := range data.Planets {
 223                         best_gain := 0
 224                         price_list := data.Planets[from].RelativePrices
 225                         if len(data.Planets[to].RelativePrices) < len(data.Planets[from].RelativePrices) {
 226                                 price_list = data.Planets[to].RelativePrices
 227                         }
 228                         for commodity := range price_list {
 229                                 gain := TradeValue(data,
 230                                         data.Planets[from],
 231                                         data.Planets[to],
 232                                         commodity,
 233                                         10000000,
 234                                         1)
 235                                 if gain > best_gain {
 236                                         best[data.pi[from]][data.pi[to]] = commodity
 237                                         gain = best_gain
 238                                 }
 239                         }
 240                 }
 241         }
 242         return best
 243 }
 244
 245 // (Example of a use case for generics in Go)
 246 func IndexPlanets(m *map[string]Planet) map[string]int {
 247         index := make(map[string]int, len(*m))
 248         i := 0
 249         for e := range *m {
 250                 index[e] = i
 251                 i++
 252         }
 253         return index
 254 }
 255 func IndexCommodities(m *map[string]Commodity) map[string]int {
 256         index := make(map[string]int, len(*m))
 257         i := 0
 258         for e := range *m {
 259                 index[e] = i
 260                 i++
 261         }
 262         return index
 263 }
 264
 265 func main() {
 266         flag.Parse()
 267         data := ReadData()
 268         data.pi = IndexPlanets(&data.Planets)
 269         data.ci = IndexCommodities(&data.Commodities)
 270         dims := DimensionSizes(data)
 271         table := NewStateTable(dims)
 272         table[0] = State{1, 1}
 273         best_trades := FindBestTrades(data)
 274
 275         for from := range data.Planets {
 276                 for to := range data.Planets {
 277                         best_trade := "(nothing)"
 278                         if best_trades[data.pi[from]][data.pi[to]] != "" {
 279                                 best_trade = best_trades[data.pi[from]][data.pi[to]]
 280                         }
 281                         fmt.Printf("%s to %s: %s\n", from, to, best_trade)
 282                 }
 283         }
 284 }