Able to read rules and messages

day19/day19.go

@@ -0,0 +1,103 @@
+package main
+
+import (
+	"bufio"
+	"fmt"
+	"log"
+	"os"
+	"strconv"
+	"strings"
+)
+
+type rule struct {
+	value   string
+	mapping [][]int
+}
+
+var rules map[int]rule
+
+func init() {
+	rules = make(map[int]rule)
+}
+
+func readRule(line string) {
+	var newRule rule
+	parts := strings.Split(line, ": ")
+	if len(parts) != 2 {
+		log.Fatalf("Invalid line: %s", line)
+	}
+
+	id, err := strconv.Atoi(parts[0])
+	if err != nil {
+		log.Fatalf("Error processing rule id for %s: %s", line, err)
+	}
+
+	var currentMapping []int
+	for _, item := range strings.Split(parts[1], " ") {
+		if strings.Contains(item, "\"") {
+			newRule.value = strings.ReplaceAll(item, "\"", "")
+			break
+		}
+
+		if item == "|" {
+			newRule.mapping = append(newRule.mapping, currentMapping)
+			currentMapping = []int{}
+			continue
+		}
+
+		itemID, err := strconv.Atoi(item)
+		if err != nil {
+			log.Fatalf("Error processing id for %s: %s", item, err)
+		}
+
+		currentMapping = append(currentMapping, itemID)
+	}
+	newRule.mapping = append(newRule.mapping, currentMapping)
+
+	rules[id] = newRule
+}
+
+var messages []string
+
+func readFile(file *os.File) {
+	scanner := bufio.NewScanner(file)
+	currentFunction := readRule
+	changed := false
+	for scanner.Scan() {
+		line := scanner.Text()
+		if line == "" {
+			if changed {
+				break
+			}
+
+			currentFunction = func(line string) { messages = append(messages, line) }
+			changed = true
+			continue
+		}
+
+		currentFunction(line)
+	}
+	if err := scanner.Err(); err != nil {
+		log.Fatalf("Scanner error: %s", err)
+	}
+}
+
+func main() {
+	if len(os.Args) < 2 {
+		log.Fatal("You need to specify a file!")
+	}
+
+	filePath := os.Args[1]
+	file, err := os.Open(filePath)
+	if err != nil {
+		log.Fatalf("Failed to open %s!\n", filePath)
+
+	}
+
+	readFile(file)
+	if err := file.Close(); err != nil {
+		log.Fatalf("Failed to close file: %s", err)
+	}
+
+	fmt.Println(rules, messages)
+}