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 {
 130                 return 1
 131         }
 132         return 0
 133 }
 134
 135 func DimensionSizes(data planet_data) []int {
 136         eden_capacity := data.Commodities["Eden Warp Units"].Limit
 137         cloak_capacity := bint(*cloak)
 138         dims := []int{
 139                 eden_capacity + 1,
 140                 cloak_capacity + 1,
 141                 eden_capacity + cloak_capacity + 1,
 142                 *fuel + 1,
 143                 len(data.Planets),
 144                 len(data.Commodities),
 145                 bint(*drones > 0) + 1,
 146                 bint(*batteries > 0) + 1,
 147                 1 << uint(len(visit())),
 148         }
 149         if len(dims) != NumDimensions {
 150                 panic("Dimensionality mismatch")
 151         }
 152         return dims
 153 }
 154
 155 func StateTableSize(dims []int) int {
 156         sum := 0
 157         for _, size := range dims {
 158                 sum += size
 159         }
 160         return sum
 161 }
 162
 163 type State struct {
 164         funds, from int
 165 }
 166
 167 func NewStateTable(dims []int) []State {
 168         return make([]State, StateTableSize(dims))
 169 }
 170
 171 func EncodeIndex(dims, addr []int) int {
 172         index := addr[0]
 173         for i := 1; i < len(dims); i++ {
 174                 index = index*dims[i] + addr[i]
 175         }
 176         return index
 177 }
 178
 179 func DecodeIndex(dims []int, index int) []int {
 180         addr := make([]int, len(dims))
 181         for i := len(dims) - 1; i > 0; i-- {
 182                 addr[i] = index % dims[i]
 183                 index /= dims[i]
 184         }
 185         addr[0] = index
 186         return addr
 187 }
 188
 189 /* What is the value of hauling 'commodity' from 'from' to 'to'?
 190  * Take into account the available funds and the available cargo space. */
 191 func TradeValue(data planet_data,
 192 from, to Planet,
 193 commodity string,
 194 initial_funds, max_quantity int) int {
 195         if !data.Commodities[commodity].CanSell {
 196                 return 0
 197         }
 198         from_relative_price, from_available := from.RelativePrices[commodity]
 199         if !from_available {
 200                 return 0
 201         }
 202         to_relative_price, to_available := to.RelativePrices[commodity]
 203         if !to_available {
 204                 return 0
 205         }
 206
 207         base_price := data.Commodities[commodity].BasePrice
 208         from_absolute_price := from_relative_price * base_price
 209         to_absolute_price := to_relative_price * base_price
 210         buy_price := from_absolute_price
 211         sell_price := int(float64(to_absolute_price) * 0.9)
 212         var can_afford int = initial_funds / buy_price
 213         quantity := can_afford
 214         if quantity > max_quantity {
 215                 quantity = max_quantity
 216         }
 217         return (sell_price - buy_price) * max_quantity
 218 }
 219
 220 func FindBestTrades(data planet_data) [][]string {
 221         // TODO: We can't cache this because this can change based on available funds.
 222         best := make([][]string, len(data.Planets))
 223         for from := range data.Planets {
 224                 best[data.pi[from]] = make([]string, len(data.Planets))
 225                 for to := range data.Planets {
 226                         best_gain := 0
 227                         price_list := data.Planets[from].RelativePrices
 228                         if len(data.Planets[to].RelativePrices) < len(data.Planets[from].RelativePrices) {
 229                                 price_list = data.Planets[to].RelativePrices
 230                         }
 231                         for commodity := range price_list {
 232                                 gain := TradeValue(data,
 233                                         data.Planets[from],
 234                                         data.Planets[to],
 235                                         commodity,
 236                                         10000000,
 237                                         1)
 238                                 if gain > best_gain {
 239                                         best[data.pi[from]][data.pi[to]] = commodity
 240                                         gain = best_gain
 241                                 }
 242                         }
 243                 }
 244         }
 245         return best
 246 }
 247
 248 // (Example of a use case for generics in Go)
 249 func IndexPlanets(m *map[string]Planet) map[string]int {
 250         index := make(map[string]int, len(*m))
 251         i := 0
 252         for e := range *m {
 253                 index[e] = i
 254                 i++
 255         }
 256         return index
 257 }
 258 func IndexCommodities(m *map[string]Commodity) map[string]int {
 259         index := make(map[string]int, len(*m))
 260         i := 0
 261         for e := range *m {
 262                 index[e] = i
 263                 i++
 264         }
 265         return index
 266 }
 267
 268 func main() {
 269         flag.Parse()
 270         data := ReadData()
 271         data.pi = IndexPlanets(&data.Planets)
 272         data.ci = IndexCommodities(&data.Commodities)
 273         dims := DimensionSizes(data)
 274         table := NewStateTable(dims)
 275         table[0] = State{1, 1}
 276         best_trades := FindBestTrades(data)
 277
 278         for from := range data.Planets {
 279                 for to := range data.Planets {
 280                         best_trade := "(nothing)"
 281                         if best_trades[data.pi[from]][data.pi[to]] != "" {
 282                                 best_trade = best_trades[data.pi[from]][data.pi[to]]
 283                         }
 284                         fmt.Printf("%s to %s: %s\n", from, to, best_trade)
 285                 }
 286         }
 287 }