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 planets to end at")
  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,
  36         "Reactor units; How many non-Eden jumps we can make " +
  37         "(but remember that deviating from the flight plan " +
  38         "costs two units of fuel per jump)")
  39
  40 var start_edens = flag.Int("start_edens", 0,
  41         "How many Eden Warp Units are you starting with?")
  42
  43 var end_edens = flag.Int("end_edens", 0,
  44         "How many Eden Warp Units would you like to keep (not use)?")
  45
  46 var cloak = flag.Bool("cloak", false,
  47         "Make sure to end with a Device of Cloaking")
  48
  49 var drones = flag.Int("drones", 0,
  50         "Buy this many Fighter Drones")
  51
  52 var batteries = flag.Int("batteries", 0,
  53         "Buy this many Shield Batterys")
  54
  55 var visit_string = flag.String("visit", "",
  56         "A comma-separated list of planets to make sure to visit")
  57
  58 func visit() []string {
  59         return strings.Split(*visit_string, ",")
  60 }
  61
  62 type Commodity struct {
  63         BasePrice int
  64         CanSell   bool
  65         Limit     int
  66 }
  67 type Planet struct {
  68         BeaconOn bool
  69         /* Use relative prices rather than absolute prices because you
  70            can get relative prices without traveling to each planet. */
  71         RelativePrices map [string] int
  72 }
  73 type planet_data struct {
  74         Commodities map [string] Commodity
  75         Planets map [string] Planet
  76         pi, ci map [string] int  // Generated; not read from file
  77 }
  78
  79 func ReadData() (data planet_data) {
  80         f, err := os.Open(*planet_data_file)
  81         if err != nil {
  82                 panic(err)
  83         }
  84         defer f.Close()
  85         err = json.NewDecoder(f).Decode(&data)
  86         if err != nil {
  87                 panic(err)
  88         }
  89         return
  90 }
  91
  92 /* This program operates by filling in a state table representing the best
  93  * possible trips you could make; the ones that makes you the most money.
  94  * This is feasible because we don't look at all the possible trips.
  95  * We define a list of things that are germane to this game and then only
  96  * consider the best outcome in each possible game state.
  97  *
  98  * Each cell in the table represents a state in the game.  In each cell,
  99  * we track two things: 1. the most money you could possibly have while in
 100  * that state and 2. one possible way to get into that state with that
 101  * amount of money.
 102  *
 103  * A basic analysis can be done with a two-dimensional table: location and
 104  * fuel.  planeteer-1.0 used this two-dimensional table.  This version
 105  * adds features mostly by adding dimensions to this table.
 106  *
 107  * Note that the sizes of each dimension are data driven.  Many dimensions
 108  * collapse to one possible value (ie, disappear) if the corresponding
 109  * feature is not enabled.
 110  */
 111
 112 // The official list of dimensions:
 113 const (
 114         // Name          Num  Size  Description
 115         Edens = iota  //   1     3  # of Eden warp units (0 - 2 typically)
 116         Cloaks        //   2     2  # of Devices of Cloaking (0 or 1)
 117         UnusedCargo   //   3     4  # of unused cargo spaces (0 - 3 typically)
 118         Fuel          //   4    17  Reactor power left (0 - 16)
 119         Location      //   5    26  Location (which planet)
 120         Hold          //   6    15  Cargo bay contents (a *Commodity or nil)
 121         NeedFighters  //   7     2  Errand: Buy fighter drones (needed or not)
 122         NeedShields   //   8     2  Errand: Buy shield batteries (needed or not)
 123         Visit         //   9  2**N  Visit: Stop by these N planets in the route
 124
 125         NumDimensions
 126 )
 127
 128 func bint(b bool) int {
 129         if b { return 1 }
 130         return 0
 131 }
 132
 133 func DimensionSizes(data planet_data) []int {
 134         eden_capacity := data.Commodities["Eden Warp Units"].Limit
 135         cloak_capacity := bint(*cloak)
 136         dims := []int{
 137                 eden_capacity + 1,
 138                 cloak_capacity + 1,
 139                 eden_capacity + cloak_capacity + 1,
 140                 *fuel + 1,
 141                 len(data.Planets),
 142                 len(data.Commodities),
 143                 bint(*drones > 0) + 1,
 144                 bint(*batteries > 0) + 1,
 145                 1 << uint(len(visit())),
 146         }
 147         if len(dims) != NumDimensions {
 148                 panic("Dimensionality mismatch")
 149         }
 150         return dims
 151 }
 152
 153 func StateTableSize(dims []int) int {
 154         sum := 0
 155         for _, size := range dims {
 156                 sum += size
 157         }
 158         return sum
 159 }
 160
 161 type State struct {
 162         funds, from int
 163 }
 164
 165 func NewStateTable(dims []int) []State {
 166         return make([]State, StateTableSize(dims))
 167 }
 168
 169 func EncodeIndex(dims, addr []int) int {
 170         index := addr[0]
 171         for i := 1; i < len(dims); i++ {
 172                 index = index * dims[i] + addr[i]
 173         }
 174         return index
 175 }
 176
 177 func DecodeIndex(dims []int, index int) []int {
 178         addr := make([]int, len(dims))
 179         for i := len(dims) - 1; i > 0; i-- {
 180                 addr[i] = index % dims[i]
 181                 index /= dims[i]
 182         }
 183         addr[0] = index
 184         return addr
 185 }
 186
 187 /* What is the value of hauling 'commodity' from 'from' to 'to'?
 188  * Take into account the available funds and the available cargo space. */
 189 func TradeValue(data planet_data,
 190                 from, to Planet,
 191                 commodity string,
 192                 initial_funds, max_quantity int) int {
 193         if !data.Commodities[commodity].CanSell {
 194                 return 0
 195         }
 196         from_relative_price, from_available := from.RelativePrices[commodity]
 197         if !from_available {
 198                 return 0
 199         }
 200         to_relative_price, to_available := to.RelativePrices[commodity]
 201         if !to_available {
 202                 return 0
 203         }
 204
 205         base_price := data.Commodities[commodity].BasePrice
 206         from_absolute_price := from_relative_price * base_price
 207         to_absolute_price := to_relative_price * base_price
 208         buy_price := from_absolute_price
 209         sell_price := int(float64(to_absolute_price) * 0.9)
 210         var can_afford int = initial_funds / buy_price
 211         quantity := can_afford
 212         if quantity > max_quantity {
 213                 quantity = max_quantity
 214         }
 215         return (sell_price - buy_price) * max_quantity
 216 }
 217
 218 func FindBestTrades(data planet_data) [][]string {
 219         // TODO: We can't cache this because this can change based on available funds.
 220         best := make([][]string, len(data.Planets))
 221         for from := range data.Planets {
 222                 best[data.pi[from]] = make([]string, len(data.Planets))
 223                 for to := range data.Planets {
 224                         best_gain := 0
 225                         price_list := data.Planets[from].RelativePrices
 226                         if len(data.Planets[to].RelativePrices) < len(data.Planets[from].RelativePrices) {
 227                                 price_list = data.Planets[to].RelativePrices
 228                         }
 229                         for commodity := range price_list {
 230                                 gain := TradeValue(data,
 231                                                    data.Planets[from],
 232                                                    data.Planets[to],
 233                                                    commodity,
 234                                                    10000000,
 235                                                    1)
 236                                 if gain > best_gain {
 237                                         best[data.pi[from]][data.pi[to]] = commodity
 238                                         gain = best_gain
 239                                 }
 240                         }
 241                 }
 242         }
 243         return best
 244 }
 245
 246 // (Example of a use case for generics in Go)
 247 func IndexPlanets(m *map [string] Planet) map [string] int {
 248         index := make(map [string] int, len(*m))
 249         i := 0
 250         for e := range *m {
 251                 index[e] = i
 252                 i++
 253         }
 254         return index
 255 }
 256 func IndexCommodities(m *map [string] Commodity) map [string] int {
 257         index := make(map [string] int, len(*m))
 258         i := 0
 259         for e := range *m {
 260                 index[e] = i
 261                 i++
 262         }
 263         return index
 264 }
 265
 266 func main() {
 267         flag.Parse()
 268         data := ReadData()
 269         data.pi = IndexPlanets(&data.Planets)
 270         data.ci = IndexCommodities(&data.Commodities)
 271         dims := DimensionSizes(data)
 272         table := NewStateTable(dims)
 273         table[0] = State{ 1, 1 }
 274         best_trades := FindBestTrades(data)
 275
 276         for from := range data.Planets {
 277                 for to := range data.Planets {
 278                         best_trade := "(nothing)"
 279                         if best_trades[data.pi[from]][data.pi[to]] != "" {
 280                                 best_trade = best_trades[data.pi[from]][data.pi[to]]
 281                         }
 282                         fmt.Printf("%s to %s: %s\n", from, to, best_trade)
 283                 }
 284         }
 285 }