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[planeteer] / 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 }