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 "runtime/pprof"
  25 import "strings"
  26
  27 var funds = flag.Int("funds", 0,
  28         "Starting funds")
  29
  30 var start = flag.String("start", "",
  31         "The planet to start at")
  32
  33 var flight_plan_string = flag.String("flight_plan", "",
  34         "Your hyper-holes for the day, comma-separated.")
  35
  36 var end_string = flag.String("end", "",
  37         "A comma-separated list of acceptable ending planets.")
  38
  39 var planet_data_file = flag.String("planet_data_file", "planet-data",
  40         "The file to read planet data from")
  41
  42 var fuel = flag.Int("fuel", 16, "Hyper Jump power left")
  43
  44 var hold = flag.Int("hold", 300, "Size of your cargo hold")
  45
  46 var start_edens = flag.Int("start_edens", 0,
  47         "How many Eden Warp Units are you starting with?")
  48
  49 var end_edens = flag.Int("end_edens", 0,
  50         "How many Eden Warp Units would you like to keep (not use)?")
  51
  52 var cloak = flag.Bool("cloak", false,
  53         "Make sure to end with a Device of Cloaking")
  54
  55 var drones = flag.Int("drones", 0, "Buy this many Fighter Drones")
  56
  57 var batteries = flag.Int("batteries", 0, "Buy this many Shield Batterys")
  58
  59 var drone_price = flag.Int("drone_price", 0, "Today's Fighter Drone price")
  60
  61 var battery_price = flag.Int("battery_price", 0, "Today's Shield Battery price")
  62
  63 var visit_string = flag.String("visit", "",
  64         "A comma-separated list of planets to make sure to visit")
  65
  66 var cpuprofile = flag.String("cpuprofile", "", "write cpu profile to file")
  67
  68 var visit_cache []string
  69
  70 func visit() []string {
  71         if visit_cache == nil {
  72                 if *visit_string == "" {
  73                         return nil
  74                 }
  75                 visit_cache = strings.Split(*visit_string, ",")
  76         }
  77         return visit_cache
  78 }
  79
  80 var flight_plan_cache []string
  81
  82 func flight_plan() []string {
  83         if flight_plan_cache == nil {
  84                 if *flight_plan_string == "" {
  85                         return nil
  86                 }
  87                 flight_plan_cache = strings.Split(*flight_plan_string, ",")
  88         }
  89         return flight_plan_cache
  90 }
  91
  92 var end_cache map[string]bool
  93
  94 func end() map[string]bool {
  95         if end_cache == nil {
  96                 if *end_string == "" {
  97                         return nil
  98                 }
  99                 m := make(map[string]bool)
 100                 for _, p := range strings.Split(*end_string, ",") {
 101                         m[p] = true
 102                 }
 103                 end_cache = m
 104         }
 105         return end_cache
 106 }
 107
 108 type Commodity struct {
 109         BasePrice int
 110         CanSell   bool
 111         Limit     int
 112 }
 113 type Planet struct {
 114         BeaconOn bool
 115         Private  bool
 116         /* Use relative prices rather than absolute prices because you
 117            can get relative prices without traveling to each planet. */
 118         RelativePrices map[string]int
 119 }
 120 type planet_data struct {
 121         Commodities map[string]Commodity
 122         Planets     map[string]Planet
 123         p2i, c2i    map[string]int // Generated; not read from file
 124         i2p, i2c    []string       // Generated; not read from file
 125 }
 126
 127 func ReadData() (data planet_data) {
 128         f, err := os.Open(*planet_data_file)
 129         if err != nil {
 130                 panic(err)
 131         }
 132         defer f.Close()
 133         err = json.NewDecoder(f).Decode(&data)
 134         if err != nil {
 135                 panic(err)
 136         }
 137         return
 138 }
 139
 140 /* This program operates by filling in a state table representing the best
 141  * possible trips you could make; the ones that makes you the most money.
 142  * This is feasible because we don't look at all the possible trips.
 143  * We define a list of things that are germane to this game and then only
 144  * consider the best outcome in each possible game state.
 145  *
 146  * Each cell in the table represents a state in the game.  In each cell,
 147  * we track two things: 1. the most money you could possibly have while in
 148  * that state and 2. one possible way to get into that state with that
 149  * amount of money.
 150  *
 151  * A basic analysis can be done with a two-dimensional table: location and
 152  * fuel.  planeteer-1.0 used this two-dimensional table.  This version
 153  * adds features mostly by adding dimensions to this table.
 154  *
 155  * Note that the sizes of each dimension are data driven.  Many dimensions
 156  * collapse to one possible value (ie, disappear) if the corresponding
 157  * feature is not enabled.
 158  *
 159  * The order of the dimensions in the list of constants below determines
 160  * their layout in RAM.  The cargo-based 'dimensions' are not completely
 161  * independent -- some combinations are illegal and not used.  They are
 162  * handled as three dimensions rather than one for simplicity.  Placing
 163  * these dimensions first causes the unused cells in the table to be
 164  * grouped together in large blocks.  This keeps them from polluting
 165  * cache lines, and if they are large enough, allows the memory manager
 166  * to swap out entire pages.
 167  *
 168  * If the table gets too big to fit in RAM:
 169  *    * Combine the Edens, Cloaks, and UnusedCargo dimensions.  Of the
 170  *      24 combinations, only 15 are legal: a 38% savings.
 171  *    * Reduce the size of the Fuel dimension to 3.  We only ever look
 172  *      backwards 2 units, so just rotate the logical values through
 173  *      the same 3 physical addresses.  This is good for an 82% savings.
 174  *    * Reduce the size of the Edens dimension from 3 to 2, for the
 175  *      same reasons as Fuel above.  33% savings.
 176  *    * Buy more ram.  (Just sayin'.  It's cheaper than you think.)
 177  *
 178  */
 179
 180 // The official list of dimensions:
 181 const (
 182         // Name                Num   Size  Description
 183         Edens       = iota //   1      3  # of Eden warp units (0 - 2 typically)
 184         Cloaks             //   2    1-2  # of Devices of Cloaking (0 or 1)
 185         UnusedCargo        //   3      4  # of unused cargo spaces (0 - 3 typically)
 186         Fuel               //   4     17  Hyper jump power left (0 - 16)
 187         Location           //   5     26  Location (which planet)
 188         Hold               //   6     15  Cargo bay contents (a *Commodity or nil)
 189         Traded             //   7      2  Traded yet?
 190         BuyFighters        //   8    1-2  Errand: Buy fighter drones
 191         BuyShields         //   9    1-2  Errand: Buy shield batteries
 192         Visit              //  10 1-2**N  Visit: Stop by these N planets in the route
 193
 194         NumDimensions
 195 )
 196
 197 func bint(b bool) int {
 198         if b {
 199                 return 1
 200         }
 201         return 0
 202 }
 203
 204 func DimensionSizes(data planet_data) []int {
 205         eden_capacity := data.Commodities["Eden Warp Units"].Limit
 206         if *start_edens > eden_capacity {
 207                 eden_capacity = *start_edens
 208         }
 209         cloak_capacity := bint(*cloak)
 210         dims := make([]int, NumDimensions)
 211         dims[Edens] = eden_capacity + 1
 212         dims[Cloaks] = cloak_capacity + 1
 213         dims[UnusedCargo] = eden_capacity + cloak_capacity + 1
 214         dims[Fuel] = *fuel + 1
 215         dims[Location] = len(data.Planets)
 216         dims[Hold] = len(data.Commodities) + 1
 217         dims[Traded] = 2
 218         dims[BuyFighters] = bint(*drones > 0) + 1
 219         dims[BuyShields] = bint(*batteries > 0) + 1
 220         dims[Visit] = 1 << uint(len(visit()))
 221
 222         // Remind myself to add a line above when adding new dimensions
 223         for i, dim := range dims {
 224                 if dim < 1 {
 225                         panic(i)
 226                 }
 227         }
 228         return dims
 229 }
 230
 231 func StateTableSize(dims []int) int {
 232         product := 1
 233         for _, size := range dims {
 234                 product *= size
 235         }
 236         return product
 237 }
 238
 239 type State struct {
 240         value, from int32
 241 }
 242
 243 const (
 244         FROM_ROOT = -2147483647 + iota
 245         FROM_UNINITIALIZED
 246         VALUE_UNINITIALIZED
 247         VALUE_BEING_EVALUATED
 248         VALUE_RUBISH
 249 )
 250
 251 func EncodeIndex(dims, addr []int) int32 {
 252         index := addr[0]
 253         if addr[0] > dims[0] {
 254                 panic(0)
 255         }
 256         for i := 1; i < NumDimensions; i++ {
 257                 if addr[i] < 0 || addr[i] >= dims[i] {
 258                         panic(i)
 259                 }
 260                 index = index*dims[i] + addr[i]
 261         }
 262         return int32(index)
 263 }
 264
 265 func DecodeIndex(dims []int, index int32) []int {
 266         addr := make([]int, NumDimensions)
 267         for i := NumDimensions - 1; i > 0; i-- {
 268                 addr[i] = int(index) % dims[i]
 269                 index /= int32(dims[i])
 270         }
 271         addr[0] = int(index)
 272         return addr
 273 }
 274
 275 func CreateStateTable(data planet_data, dims []int) []State {
 276         table := make([]State, StateTableSize(dims))
 277         for i := range table {
 278                 table[i].value = VALUE_UNINITIALIZED
 279                 table[i].from = FROM_UNINITIALIZED
 280         }
 281
 282         addr := make([]int, NumDimensions)
 283         addr[Fuel] = *fuel
 284         addr[Edens] = *start_edens
 285         addr[Location] = data.p2i[*start]
 286         addr[Traded] = 1
 287         start_index := EncodeIndex(dims, addr)
 288         table[start_index].value = int32(*funds)
 289         table[start_index].from = FROM_ROOT
 290
 291         return table
 292 }
 293
 294 /* CellValue fills in the one cell at address addr by looking at all
 295  * the possible ways to reach this cell and selecting the best one. */
 296
 297 func Consider(data planet_data, dims []int, table []State, there []int, value_difference int, best_value *int32, best_source []int) {
 298         there_value := CellValue(data, dims, table, there)
 299         if value_difference < 0 && int32(-value_difference) > there_value {
 300                 /* Can't afford this transition */
 301                 return
 302         }
 303         possible_value := there_value + int32(value_difference)
 304         if possible_value > *best_value {
 305                 *best_value = possible_value
 306                 copy(best_source, there)
 307         }
 308 }
 309
 310 var cell_filled_count int
 311
 312 func CellValue(data planet_data, dims []int, table []State, addr []int) int32 {
 313         my_index := EncodeIndex(dims, addr)
 314         if table[my_index].value == VALUE_BEING_EVALUATED {
 315                 panic("Circular dependency")
 316         }
 317         if table[my_index].value != VALUE_UNINITIALIZED {
 318                 return table[my_index].value
 319         }
 320         table[my_index].value = VALUE_BEING_EVALUATED
 321
 322         best_value := int32(VALUE_RUBISH)
 323         best_source := make([]int, NumDimensions)
 324         other := make([]int, NumDimensions)
 325         copy(other, addr)
 326         planet := data.i2p[addr[Location]]
 327
 328         /* Travel here */
 329         if addr[Traded] == 0 { /* Can't have traded immediately after traveling. */
 330                 other[Traded] = 1 /* Travel from states that have done trading. */
 331
 332                 /* Travel here via a 2-fuel unit jump */
 333                 if addr[Fuel]+2 < dims[Fuel] {
 334                         other[Fuel] = addr[Fuel] + 2
 335                         hole_index := (dims[Fuel] - 1) - (addr[Fuel] + 2)
 336                         if hole_index >= len(flight_plan()) || addr[Location] != data.p2i[flight_plan()[hole_index]] {
 337                                 for other[Location] = 0; other[Location] < dims[Location]; other[Location]++ {
 338                                         if data.Planets[data.i2p[addr[Location]]].BeaconOn {
 339                                                 Consider(data, dims, table, other, 0, &best_value, best_source)
 340                                         }
 341                                 }
 342                         }
 343                         other[Location] = addr[Location]
 344                         other[Fuel] = addr[Fuel]
 345                 }
 346
 347                 /* Travel here via a 1-fuel unit jump (a hyper hole) */
 348                 if addr[Fuel]+1 < dims[Fuel] {
 349                         hole_index := (dims[Fuel] - 1) - (addr[Fuel] + 1)
 350                         if hole_index < len(flight_plan()) && addr[Location] == data.p2i[flight_plan()[hole_index]] {
 351                                 other[Fuel] = addr[Fuel] + 1
 352                                 for other[Location] = 0; other[Location] < dims[Location]; other[Location]++ {
 353                                         Consider(data, dims, table, other, 0, &best_value, best_source)
 354                                 }
 355                                 other[Location] = addr[Location]
 356                                 other[Fuel] = addr[Fuel]
 357                         }
 358                 }
 359
 360                 /* Travel here via Eden Warp Unit */
 361                 if addr[Edens]+1 < dims[Edens] && addr[UnusedCargo] > 0 {
 362                         _, available := data.Planets[data.i2p[addr[Location]]].RelativePrices["Eden Warp Units"]
 363                         if !available {
 364                                 other[Edens] = addr[Edens] + 1
 365                                 if other[Hold] != 0 {
 366                                         other[UnusedCargo] = addr[UnusedCargo] - 1
 367                                 }
 368                                 for other[Location] = 0; other[Location] < dims[Location]; other[Location]++ {
 369                                         Consider(data, dims, table, other, 0, &best_value, best_source)
 370                                 }
 371                                 other[Location] = addr[Location]
 372                                 other[UnusedCargo] = addr[UnusedCargo]
 373                                 other[Edens] = addr[Edens]
 374                         }
 375                 }
 376                 other[Traded] = addr[Traded]
 377         }
 378
 379         /* Trade */
 380         if addr[Traded] == 1 {
 381                 other[Traded] = 0
 382
 383                 /* Consider not trading */
 384                 Consider(data, dims, table, other, 0, &best_value, best_source)
 385
 386                 if !data.Planets[data.i2p[addr[Location]]].Private {
 387
 388                         /* Sell */
 389                         if addr[Hold] == 0 && addr[UnusedCargo] == 0 {
 390                                 for other[Hold] = 0; other[Hold] < dims[Hold]; other[Hold]++ {
 391                                         commodity := data.i2c[other[Hold]]
 392                                         if !data.Commodities[commodity].CanSell {
 393                                                 continue
 394                                         }
 395                                         relative_price, available := data.Planets[planet].RelativePrices[commodity]
 396                                         if !available {
 397                                                 // TODO: Dump cargo
 398                                                 continue
 399                                         }
 400                                         base_price := data.Commodities[commodity].BasePrice
 401                                         absolute_price := float64(base_price) * float64(relative_price) / 100.0
 402                                         sell_price := int(absolute_price * 0.9)
 403
 404                                         for other[UnusedCargo] = 0; other[UnusedCargo] < dims[UnusedCargo]; other[UnusedCargo]++ {
 405                                                 quantity := *hold - (other[UnusedCargo] + other[Cloaks] + other[Edens])
 406                                                 sale_value := quantity * sell_price
 407                                                 Consider(data, dims, table, other, sale_value, &best_value, best_source)
 408                                         }
 409                                 }
 410                                 other[UnusedCargo] = addr[UnusedCargo]
 411                                 other[Hold] = addr[Hold]
 412                         }
 413
 414                         /* Buy */
 415                         other[Traded] = addr[Traded] /* Buy after selling */
 416                         if addr[Hold] != 0 {
 417                                 commodity := data.i2c[addr[Hold]]
 418                                 if data.Commodities[commodity].CanSell {
 419                                         relative_price, available := data.Planets[planet].RelativePrices[commodity]
 420                                         if available {
 421                                                 base_price := data.Commodities[commodity].BasePrice
 422                                                 absolute_price := int(float64(base_price) * float64(relative_price) / 100.0)
 423                                                 quantity := *hold - (addr[UnusedCargo] + addr[Cloaks] + addr[Edens])
 424                                                 total_price := quantity * absolute_price
 425                                                 other[Hold] = 0
 426                                                 other[UnusedCargo] = 0
 427                                                 Consider(data, dims, table, other, -total_price, &best_value, best_source)
 428                                                 other[UnusedCargo] = addr[UnusedCargo]
 429                                                 other[Hold] = addr[Hold]
 430                                         }
 431                                 }
 432                         }
 433                 }
 434                 other[Traded] = addr[Traded]
 435         }
 436
 437         /* Buy a Device of Cloaking */
 438         if addr[Cloaks] == 1 && addr[UnusedCargo] < dims[UnusedCargo]-1 {
 439                 relative_price, available := data.Planets[data.i2p[addr[Location]]].RelativePrices["Device Of Cloakings"]
 440                 if available {
 441                         absolute_price := int(float64(data.Commodities["Device Of Cloakings"].BasePrice) * float64(relative_price) / 100.0)
 442                         other[Cloaks] = 0
 443                         if other[Hold] != 0 {
 444                                 other[UnusedCargo] = addr[UnusedCargo] + 1
 445                         }
 446                         Consider(data, dims, table, other, -absolute_price, &best_value, best_source)
 447                         other[UnusedCargo] = addr[UnusedCargo]
 448                         other[Cloaks] = addr[Cloaks]
 449                 }
 450         }
 451
 452         /* Buy Fighter Drones */
 453         if addr[BuyFighters] == 1 {
 454                 relative_price, available := data.Planets[data.i2p[addr[Location]]].RelativePrices["Fighter Drones"]
 455                 if available {
 456                         absolute_price := int(float64(data.Commodities["Fighter Drones"].BasePrice) * float64(relative_price) / 100.0)
 457                         other[BuyFighters] = 0
 458                         Consider(data, dims, table, other, -absolute_price**drones, &best_value, best_source)
 459                         other[BuyFighters] = addr[BuyFighters]
 460                 }
 461         }
 462
 463         /* Buy Shield Batteries */
 464         if addr[BuyShields] == 1 {
 465                 relative_price, available := data.Planets[data.i2p[addr[Location]]].RelativePrices["Shield Batterys"]
 466                 if available {
 467                         absolute_price := int(float64(data.Commodities["Shield Batterys"].BasePrice) * float64(relative_price) / 100.0)
 468                         other[BuyShields] = 0
 469                         Consider(data, dims, table, other, -absolute_price**batteries, &best_value, best_source)
 470                         other[BuyShields] = addr[BuyShields]
 471                 }
 472         }
 473
 474         /* Visit this planet */
 475         var i uint
 476         for i = 0; i < uint(len(visit())); i++ {
 477                 if addr[Visit]&(1<<i) != 0 && visit()[i] == data.i2p[addr[Location]] {
 478                         other[Visit] = addr[Visit] & ^(1 << i)
 479                         Consider(data, dims, table, other, 0, &best_value, best_source)
 480                 }
 481         }
 482         other[Visit] = addr[Visit]
 483
 484         /* Buy Eden warp units */
 485         eden_limit := data.Commodities["Eden Warp Units"].Limit
 486         if addr[Edens] > 0 && addr[Edens] <= eden_limit {
 487                 relative_price, available := data.Planets[data.i2p[addr[Location]]].RelativePrices["Eden Warp Units"]
 488                 if available {
 489                         absolute_price := int(float64(data.Commodities["Eden Warp Units"].BasePrice) * float64(relative_price) / 100.0)
 490                         for quantity := addr[Edens]; quantity > 0; quantity-- {
 491                                 other[Edens] = addr[Edens] - quantity
 492                                 if addr[Hold] != 0 {
 493                                         other[UnusedCargo] = addr[UnusedCargo] + quantity
 494                                 }
 495                                 if other[UnusedCargo] < dims[UnusedCargo] {
 496                                         Consider(data, dims, table, other, -absolute_price*quantity, &best_value, best_source)
 497                                 }
 498                         }
 499                         other[Edens] = addr[Edens]
 500                         other[UnusedCargo] = addr[UnusedCargo]
 501                 }
 502         }
 503
 504         // Check that we didn't lose track of any temporary modifications to other.
 505         for i := 0; i < NumDimensions; i++ {
 506                 if addr[i] != other[i] {
 507                         panic(i)
 508                 }
 509         }
 510
 511         // Sanity check: This cell was in state BEING_EVALUATED
 512         // the whole time that it was being evaluated.
 513         if table[my_index].value != VALUE_BEING_EVALUATED {
 514                 panic(my_index)
 515         }
 516
 517         // Record our findings
 518         table[my_index].value = best_value
 519         table[my_index].from = EncodeIndex(dims, best_source)
 520
 521         // UI: Progress bar
 522         cell_filled_count++
 523         if cell_filled_count&0xfff == 0 {
 524                 print(fmt.Sprintf("\r%3.1f%%", 100*float64(cell_filled_count)/float64(StateTableSize(dims))))
 525         }
 526
 527         return table[my_index].value
 528 }
 529
 530 func FindBestState(data planet_data, dims []int, table []State) int32 {
 531         addr := make([]int, NumDimensions)
 532         addr[Edens] = *end_edens
 533         addr[Cloaks] = dims[Cloaks] - 1
 534         addr[BuyFighters] = dims[BuyFighters] - 1
 535         addr[BuyShields] = dims[BuyShields] - 1
 536         addr[Visit] = dims[Visit] - 1
 537         addr[Traded] = 1
 538         addr[Hold] = 0
 539         addr[UnusedCargo] = 0
 540         max_index := int32(-1)
 541         max_value := int32(0)
 542         max_fuel := 1
 543         if *fuel == 0 {
 544                 max_fuel = 0
 545         }
 546         for addr[Fuel] = 0; addr[Fuel] <= max_fuel; addr[Fuel]++ {
 547                 for addr[Location] = 0; addr[Location] < dims[Location]; addr[Location]++ {
 548                         if len(end()) == 0 || end()[data.i2p[addr[Location]]] {
 549                                 index := EncodeIndex(dims, addr)
 550                                 value := CellValue(data, dims, table, addr)
 551                                 if value > max_value {
 552                                         max_value = value
 553                                         max_index = index
 554                                 }
 555                         }
 556                 }
 557         }
 558         return max_index
 559 }
 560
 561 func Commas(n int32) (s string) {
 562         r := n % 1000
 563         n /= 1000
 564         for n > 0 {
 565                 s = fmt.Sprintf(",%03d", r) + s
 566                 r = n % 1000
 567                 n /= 1000
 568         }
 569         s = fmt.Sprint(r) + s
 570         return
 571 }
 572
 573 func DescribePath(data planet_data, dims []int, table []State, start int32) (description []string) {
 574         for index := start; table[index].from > FROM_ROOT; index = table[index].from {
 575                 if table[index].from == FROM_UNINITIALIZED {
 576                         panic(index)
 577                 }
 578                 var line string
 579                 addr := DecodeIndex(dims, index)
 580                 prev := DecodeIndex(dims, table[index].from)
 581                 if addr[Fuel] != prev[Fuel] {
 582                         from := data.i2p[prev[Location]]
 583                         to := data.i2p[addr[Location]]
 584                         line += fmt.Sprintf("Jump from %v to %v (%v hyper jump units)", from, to, prev[Fuel]-addr[Fuel])
 585                 }
 586                 if addr[Edens] == prev[Edens]-1 {
 587                         from := data.i2p[prev[Location]]
 588                         to := data.i2p[addr[Location]]
 589                         line += fmt.Sprintf("Eden warp from %v to %v", from, to)
 590                 }
 591                 if addr[Hold] != prev[Hold] {
 592                         if addr[Hold] == 0 {
 593                                 quantity := *hold - (prev[UnusedCargo] + prev[Edens] + prev[Cloaks])
 594                                 line += fmt.Sprintf("Sell %v %v", quantity, data.i2c[prev[Hold]])
 595                         } else if prev[Hold] == 0 {
 596                                 quantity := *hold - (addr[UnusedCargo] + addr[Edens] + addr[Cloaks])
 597                                 line += fmt.Sprintf("Buy %v %v", quantity, data.i2c[addr[Hold]])
 598                         } else {
 599                                 panic("Switched cargo?")
 600                         }
 601
 602                 }
 603                 if addr[Cloaks] == 1 && prev[Cloaks] == 0 {
 604                         // TODO: Dump cloaks, convert from cargo?
 605                         line += "Buy a Cloak"
 606                 }
 607                 if addr[Edens] > prev[Edens] {
 608                         line += fmt.Sprint("Buy ", addr[Edens]-prev[Edens], " Eden Warp Units")
 609                 }
 610                 if addr[BuyShields] == 1 && prev[BuyShields] == 0 {
 611                         line += fmt.Sprint("Buy ", *batteries, " Shield Batterys")
 612                 }
 613                 if addr[BuyFighters] == 1 && prev[BuyFighters] == 0 {
 614                         line += fmt.Sprint("Buy ", *drones, " Fighter Drones")
 615                 }
 616                 if addr[Visit] != prev[Visit] {
 617                         // TODO: verify that the bit chat changed is addr[Location]
 618                         line += fmt.Sprint("Visit ", data.i2p[addr[Location]])
 619                 }
 620                 if line == "" && addr[Hold] == prev[Hold] && addr[Traded] != prev[Traded] {
 621                         // The Traded dimension is for housekeeping.  It doesn't directly
 622                         // correspond to in-game actions, so don't report transitions.
 623                         continue
 624                 }
 625                 if line == "" {
 626                         line = fmt.Sprint(prev, " -> ", addr)
 627                 }
 628                 description = append(description, fmt.Sprintf("%13v ", Commas(table[index].value))+line)
 629         }
 630         return
 631 }
 632
 633 // (Example of a use case for generics in Go)
 634 func IndexPlanets(m *map[string]Planet, start_at int) (map[string]int, []string) {
 635         e2i := make(map[string]int, len(*m)+start_at)
 636         i2e := make([]string, len(*m)+start_at)
 637         i := start_at
 638         for e := range *m {
 639                 e2i[e] = i
 640                 i2e[i] = e
 641                 i++
 642         }
 643         return e2i, i2e
 644 }
 645 func IndexCommodities(m *map[string]Commodity, start_at int) (map[string]int, []string) {
 646         e2i := make(map[string]int, len(*m)+start_at)
 647         i2e := make([]string, len(*m)+start_at)
 648         i := start_at
 649         for e := range *m {
 650                 e2i[e] = i
 651                 i2e[i] = e
 652                 i++
 653         }
 654         return e2i, i2e
 655 }
 656
 657 func main() {
 658         flag.Parse()
 659         if *start == "" || *funds == 0 {
 660                 print("--start and --funds are required.  --help for more\n")
 661                 return
 662         }
 663         if *cpuprofile != "" {
 664                 f, err := os.Create(*cpuprofile)
 665                 if err != nil {
 666                         panic(err)
 667                 }
 668                 pprof.StartCPUProfile(f)
 669                 defer pprof.StopCPUProfile()
 670         }
 671         data := ReadData()
 672         if *drone_price > 0 {
 673                 temp := data.Commodities["Fighter Drones"]
 674                 temp.BasePrice = *drone_price
 675                 data.Commodities["Fighter Drones"] = temp
 676         }
 677         if *battery_price > 0 {
 678                 temp := data.Commodities["Shield Batterys"]
 679                 temp.BasePrice = *battery_price
 680                 data.Commodities["Shield Batterys"] = temp
 681         }
 682         data.p2i, data.i2p = IndexPlanets(&data.Planets, 0)
 683         data.c2i, data.i2c = IndexCommodities(&data.Commodities, 1)
 684         dims := DimensionSizes(data)
 685         table := CreateStateTable(data, dims)
 686         best := FindBestState(data, dims, table)
 687         print("\n")
 688         if best == -1 {
 689                 print("Cannot acheive success criteria\n")
 690         } else {
 691                 description := DescribePath(data, dims, table, best)
 692                 for i := len(description) - 1; i >= 0; i-- {
 693                         fmt.Println(description[i])
 694                 }
 695         }
 696 }