From 0b68cb80bfe4bffc699352acd4a4794f6f7ae39d Mon Sep 17 00:00:00 2001
From: Kistaro Windrider <kistaro@gmail.com>
Date: Sat, 18 Nov 2023 18:53:13 -0800
Subject: [PATCH] Allow CSV format, multi runs, and fully customizable errors.

---
 main/main.go | 104 ++++++++++++++++++++++++++++++++++++++++++---------
 1 file changed, 87 insertions(+), 17 deletions(-)

diff --git a/main/main.go b/main/main.go
index 9c45c5b..fd791e5 100644
--- a/main/main.go
+++ b/main/main.go
@@ -1,11 +1,25 @@
 package main
 
 import (
+	"encoding/csv"
+	"flag"
 	"fmt"
 	"git.chromaticdragon.app/kistaro/auctionsim/auctionsim"
 	"log"
+	"math"
+	"math/rand"
 	"os"
-	"strconv"
+	"strings"
+)
+
+var (
+	bidders = flag.Int("b", 1000, "Number of bidders in each auction.")
+	runs    = flag.Int("r", 1, "Number of auctions to run.")
+
+	errorDev  = flag.Float64("d", 1.0, "Standard deviation of bidder irrationality.")
+	errorMean = flag.Float64("m", 0.0, "Mean of bidder irrationality. Negative values represent a bias towards underbidding.")
+
+	format = flag.String("f", "txt", "Output format: plain text (\"txt\") or CSV (\"csv\").")
 )
 
 func deltaStr(delta float64) string {
@@ -18,25 +32,33 @@ func deltaStr(delta float64) string {
 	return "broken even"
 }
 
-func main() {
-	num := int64(1000)
-	if len(os.Args) > 1 {
-		n, err := strconv.ParseInt(os.Args[1], 0, 64)
-		if err != nil {
-			log.Fatalf("can't parse %q as a number of bidders: %v", os.Args[1], err)
-		}
-		num = n
+func normalizeFormat() error {
+	*format = strings.ToLower(*format)
+	if *format == "txt" {
+		return nil
 	}
-	if num <= 1 {
-		log.Fatalf("can't run an auction with %d bidders", num)
+	if *format == "csv" {
+		return nil
 	}
+	return fmt.Errorf("unrecognized format: %q", *format)
+}
 
-	summary := auctionsim.Summarize(auctionsim.RunAuctionVerbosely(
-		&auctionsim.CappedBidderGenerator{
-			G:   auctionsim.NormalestBidderGenerator(),
-			Lim: num,
-		},
-	))
+type emitter interface {
+	Emit(*auctionsim.ResultSummary)
+	Flush()
+}
+
+type textEmitter struct {
+	notFirst bool
+}
+
+func (t *textEmitter) Emit(summary *auctionsim.ResultSummary) {
+	if t.notFirst {
+		fmt.Println()
+		fmt.Println("-----------------")
+		fmt.Println()
+		t.notFirst = true
+	}
 	fmt.Printf("The auction winner paid ¤%f. They have %s.\n", summary.Price, deltaStr(summary.WinnerProfit))
 	fmt.Printf("The item was worth ¤%f to them.\n", summary.WinnerValue)
 	fmt.Printf("They would have paid up to ¤%f for it.\n", summary.WinnerMaxBid)
@@ -58,3 +80,51 @@ func main() {
 		fmt.Printf("They valued it ¤%f more than the winning bidder.\n", summary.ValueDelta)
 	}
 }
+
+func (*textEmitter) Flush() {}
+
+type csvEmitter struct {
+	w *csv.Writer
+}
+
+func (c *csvEmitter) Emit(summary *auctionsim.ResultSummary) {
+	c.w.Write(summary.CSVRecord())
+}
+
+func (c *csvEmitter) Flush() {
+	c.w.Flush()
+}
+
+func main() {
+	flag.Parse()
+
+	if err := normalizeFormat(); err != nil {
+		log.Fatal(err)
+	}
+
+	e := emitter(&textEmitter{})
+	if *format == "csv" {
+		w := csv.NewWriter(os.Stdout)
+		e = &csvEmitter{w}
+		w.Write(auctionsim.ResultSummaryCSVHeader())
+	}
+	defer e.Flush()
+
+	for i := 0; i < *runs; i++ {
+		g := &auctionsim.BiddersFromDistributions{
+			Values: auctionsim.NormalestDistribution(),
+			Irrationalities: &auctionsim.NormalDistribution{
+				Rand:   rand.New(rand.NewSource(int64(rand.Uint64()))),
+				StdDev: *errorDev,
+				Mean:   *errorMean,
+			},
+			Bankrolls: auctionsim.ConstDistribution(math.Inf(1)),
+		}
+		e.Emit(auctionsim.Summarize(auctionsim.RunAuctionVerbosely(
+			&auctionsim.CappedBidderGenerator{
+				G:   g,
+				Lim: int64(*bidders),
+			},
+		)))
+	}
+}