From 3eae45479b724dfe4da300b2b6c2cd7c715a4b15 Mon Sep 17 00:00:00 2001
From: Justin Lin <wancat@wancat.cc>
Date: Fri, 25 Jul 2025 02:30:09 +1000
Subject: [PATCH] feat: input and output file

---
 main.go    | 28 +++++++++++++++++++++++++---
 monthly.md | 14 +++++++-------
 params.go  |  6 ++++--
 parse.go   |  2 +-
 render.go  | 12 ++++++++----
 types.go   | 20 +++++++++++++++++++-
 6 files changed, 64 insertions(+), 18 deletions(-)

diff --git a/main.go b/main.go
index c72ee05..a501fd9 100644
--- a/main.go
+++ b/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)
+	}
 }
diff --git a/monthly.md b/monthly.md
index 1b926b4..db3cdd4 100644
--- a/monthly.md
+++ b/monthly.md
@@ -1,5 +1,5 @@
 ---
-name: "reports/${from}.md"
+output: "reports_{{.from}}.md"
 params:
   from:
     required: true
@@ -9,24 +9,24 @@ params:
     default: ~/.hledger.journal
 ---
 
-# Finance Report from {from} to {to}
+# Finance Report from {{.from}} to {{.to}}
 
 ## Previous status:
 
-{{hledger -f $file balancesheet -e $from }}
+{{ sh "hledger -f $file balancesheet -e $from" }}
 
 ## Expenses:
 
 ### Expense Summary by Category
 
-{{hledger -f $file bal expenses -b $from -e $to --depth 3 --sort amount}}
+{{ sh "hledger -f $file bal expenses -b $from -e $to --depth 3 --sort amount" }}
 
-{{hledger -f $file bal expenses -b $from -e $to --depth 2 --sort amount}}
+{{ sh "hledger -f $file bal expenses -b $from -e $to --depth 2 --sort amount" }}
 
 ## Net Income:
 
-{{hledger -f $file income -b $from -e $to --monthly}}
+{{sh "hledger -f $file income -b $from -e $to --monthly"}}
 
 ## Ending balance:
 
-{{hledger -f $file balancesheet -e $to}}
+{{sh "hledger -f $file balancesheet -e $to"}}
diff --git a/params.go b/params.go
index 65e4a36..b3bbcee 100644
--- a/params.go
+++ b/params.go
@@ -3,14 +3,16 @@ package main
 import (
 	"flag"
 	"fmt"
+	"os"
 )
 
 func parseParams(meta TemplateMeta) (ctx TemplateContext, err error) {
 	result := make(map[string]*string)
+	fs := flag.NewFlagSet("params", flag.ExitOnError)
 	for key, spec := range meta.Params {
-		result[key] = flag.String(key, spec.Default, key)
+		result[key] = fs.String(key, spec.Default, key)
 	}
-	flag.Parse()
+	fs.Parse(os.Args[2:])
 	ctx = make(TemplateContext)
 	for key, spec := range meta.Params {
 		if spec.Required && *result[key] == "" {
diff --git a/parse.go b/parse.go
index eeedd36..12fbd70 100644
--- a/parse.go
+++ b/parse.go
@@ -29,6 +29,6 @@ func parseDocument(doc string) (frontmatter string, body string, err error) {
 		return
 	}
 	frontmatter = parts[1]
-	body = parts[2]
+	body = strings.TrimLeft(parts[2], "\n ")
 	return
 }
diff --git a/render.go b/render.go
index 644d124..18ed0e3 100644
--- a/render.go
+++ b/render.go
@@ -1,8 +1,8 @@
 package main
 
 import (
+	"bytes"
 	"fmt"
-	"os"
 	"os/exec"
 	"text/template"
 )
@@ -13,7 +13,6 @@ func sh(ctx TemplateContext) func(string) string {
 		for k, v := range ctx {
 			cmd.Env = append(cmd.Env, k+"="+v)
 		}
-		fmt.Println(cmd.Environ())
 		out, err := cmd.Output()
 		if err != nil {
 			return fmt.Sprintf("> Failed to execute the command: %s\n> %s\n", cmd.Args, err.Error())
@@ -22,7 +21,7 @@ func sh(ctx TemplateContext) func(string) string {
 	}
 }
 
-func render(tmpl string, ctx TemplateContext) {
+func render(tmpl string, ctx TemplateContext) []byte {
 	funcMap := template.FuncMap{
 		"sh": sh(ctx),
 	}
@@ -30,5 +29,10 @@ func render(tmpl string, ctx TemplateContext) {
 	if err != nil {
 		panic(err)
 	}
-	t.Execute(os.Stdout, ctx)
+	var buf bytes.Buffer
+	err = t.Execute(&buf, ctx)
+	if err != nil {
+		panic(err)
+	}
+	return buf.Bytes()
 }
diff --git a/types.go b/types.go
index 9a2ebeb..0eadc74 100644
--- a/types.go
+++ b/types.go
@@ -1,6 +1,11 @@
 package main
 
-import "encoding/json"
+import (
+	"bytes"
+	"encoding/json"
+	"fmt"
+	"text/template"
+)
 
 type TemplateMeta struct {
 	Output string               `yaml:"output"`
@@ -15,6 +20,19 @@ func (meta TemplateMeta) String() string {
 	return string(data)
 }
 
+func (meta TemplateMeta) OutputFile(ctx TemplateContext) (output string, err error) {
+	tmpl, err := template.New("output").Parse(meta.Output)
+	if err != nil {
+		return "", fmt.Errorf("Failed to parse output name: %w", err)
+	}
+	var buf bytes.Buffer
+	err = tmpl.Execute(&buf, ctx)
+	if err != nil {
+		return "", fmt.Errorf("Failed to execute output name: %w", err)
+	}
+	return buf.String(), nil
+}
+
 type ParamSpec struct {
 	Required bool   `yaml:"required"`
 	Default  string `yaml:"default"`