feat: input and output file

main.go

@@ -3,6 +3,7 @@ package main
 import (
 	"fmt"
 	"log"
+	"os"
 )
 
 var tmpl = `
@@ -19,19 +20,40 @@ Start from {{ .from }}
 {{ sh "hledger bal assets -b $from" }}
 `
 
+func loadTemplate() string {
+	if len(os.Args) < 2 {
+		log.Fatal("Please input a markdown template file")
+	}
+	filename := os.Args[1]
+	dat, err := os.ReadFile(filename)
+	if err != nil {
+		log.Fatal("Failed to open the file", err)
+	}
+	return string(dat)
+}
+
 func main() {
+	tmpl := loadTemplate()
 	frontmatter, body, err := parseDocument(tmpl)
 	if err != nil {
-		panic(err)
+		log.Fatal(err)
 	}
 	templateMeta, err := parseFrontmatter(frontmatter)
 	if err != nil {
-		panic(err)
+		log.Fatal(err)
 	}
 	fmt.Println(templateMeta)
 	ctx, err := parseParams(templateMeta)
 	if err != nil {
 		log.Fatal(err)
 	}
-	render(body, ctx)
+	data := render(body, ctx)
+	output, err := templateMeta.OutputFile(ctx)
+	if err != nil {
+		panic(err)
+	}
+	err = os.WriteFile(output, data, 0644)
+	if err != nil {
+		panic(err)
+	}
 }