commit b568d0f9c9bd41e9f18873b911bb75a448307cfd
Author: Artlef <artlef@localhost>
Date:   Sun May 15 19:28:11 2022 +0200

    first commit

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..c3c7987
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1 @@
+createpairings
diff --git a/README.md b/README.md
new file mode 100644
index 0000000..85ba3a9
--- /dev/null
+++ b/README.md
@@ -0,0 +1,2 @@
+1. Write players separated by newline in players.txt
+2. Output can be redirected in a csv file: `./createpairings > results.csv`
diff --git a/go.mod b/go.mod
new file mode 100644
index 0000000..286a068
--- /dev/null
+++ b/go.mod
@@ -0,0 +1,3 @@
+module git.artlef.pw/createpairings
+
+go 1.18
diff --git a/main.go b/main.go
new file mode 100644
index 0000000..a7eea6f
--- /dev/null
+++ b/main.go
@@ -0,0 +1,91 @@
+package main
+
+import (
+	"bufio"
+	"fmt"
+	"log"
+	"os"
+)
+
+type Match struct {
+	WhitePlayer string
+	BlackPlayer string
+}
+
+func getPlayerlist() []string {
+	var playerList []string
+	file, err := os.Open("players.txt")
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer file.Close()
+
+	scanner := bufio.NewScanner(file)
+	for scanner.Scan() {
+		playerList = append(playerList, scanner.Text())
+	}
+
+	if err := scanner.Err(); err != nil {
+		log.Fatal(err)
+	}
+	return playerList
+}
+
+func main() {
+	playerList := getPlayerlist()
+	matchList := getMatchs(playerList)
+	printMatchList(matchList)
+	checkMatchList(matchList, playerList)
+}
+
+func getMatchs(playerList []string) []Match {
+	if len(playerList) == 0 {
+		return nil
+	}
+	var matchList []Match
+	subList := playerList[1:]
+	for i, player := range subList {
+		whitePlayer := playerList[0]
+		blackPlayer := player
+		if i%2 == 0 {
+			whitePlayer = player
+			blackPlayer = playerList[0]
+		}
+		matchList = append(matchList, Match{whitePlayer, blackPlayer})
+	}
+	return append(matchList, getMatchs(subList)...)
+}
+
+func printMatchList(matchList []Match) {
+	for _, match := range matchList {
+		fmt.Printf("%s,%s\n", match.WhitePlayer, match.BlackPlayer)
+	}
+}
+
+func checkMatchList(matchList []Match, playerList []string) {
+	for _, player := range playerList {
+		countWhitePlayer := countWhitePlayer(matchList, player)
+		countBlackPlayer := countBlackPlayer(matchList, player)
+		fmt.Fprintf(os.Stderr, "%s has %d games with white pieces and %d with black pieces.\n", player, countWhitePlayer, countBlackPlayer)
+	}
+}
+
+func countWhitePlayer(matchList []Match, player string) int {
+	c := 0
+	for _, match := range matchList {
+		if match.WhitePlayer == player {
+			c++
+		}
+	}
+	return c
+}
+
+func countBlackPlayer(matchList []Match, player string) int {
+	c := 0
+	for _, match := range matchList {
+		if match.BlackPlayer == player {
+			c++
+		}
+	}
+	return c
+}
diff --git a/players.txt b/players.txt
new file mode 100644
index 0000000..606113a
--- /dev/null
+++ b/players.txt
@@ -0,0 +1,3 @@
+Alice
+Bob
+Charlie