From 989116970468ab07936d6b3a946836975a1314a2 Mon Sep 17 00:00:00 2001
From: Parnic <github@parnic.com>
Date: Mon, 26 Nov 2018 15:53:01 -0600
Subject: [PATCH] Initial commit

---
 compile.go | 119 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 config.go  |   8 ++++
 main.go    |  23 +++++++++++
 3 files changed, 150 insertions(+)
 create mode 100644 compile.go
 create mode 100644 config.go
 create mode 100644 main.go

diff --git a/compile.go b/compile.go
new file mode 100644
index 0000000..1af9a24
--- /dev/null
+++ b/compile.go
@@ -0,0 +1,119 @@
+package precompiler
+
+import (
+	"bytes"
+	"crypto/sha256"
+	"encoding/hex"
+	"fmt"
+	"io/ioutil"
+	"os"
+	"path/filepath"
+
+	"github.com/tdewolff/minify"
+	"github.com/tdewolff/minify/css"
+	"github.com/tdewolff/minify/js"
+)
+
+// FileType represents a supported file extension (without the .)
+type FileType string
+
+// supported file types
+const (
+	CSS FileType = "css"
+	JS  FileType = "js"
+)
+
+func initMinify() *minify.M {
+	minifier := minify.New()
+	minifier.AddFunc("text/css", css.Minify)
+	minifier.AddFunc("text/js", js.Minify)
+	return minifier
+}
+
+func getBytes(config Config, minifier *minify.M) (map[FileType]*bytes.Buffer, error) {
+	buf := make(map[FileType]*bytes.Buffer)
+
+	for _, file := range config.Files {
+		if file, err := os.Open(file); err == nil {
+			ext := FileType(filepath.Ext(file.Name())[1:])
+			if !supportedFileType(ext) {
+				fmt.Println("Unsupported file type:", file.Name())
+				continue
+			}
+
+			if buf[ext] == nil {
+				buf[ext] = &bytes.Buffer{}
+			}
+
+			if config.Minify {
+				if err = minifier.Minify("text/"+string(ext), buf[ext], file); err != nil {
+					return nil, err
+				}
+			} else {
+				if _, err = buf[ext].ReadFrom(file); err != nil {
+					return nil, err
+				}
+			}
+		} else {
+			return nil, err
+		}
+	}
+
+	return buf, nil
+}
+
+// CompileResult holds the results of compilation
+type CompileResult struct {
+	Bytes      []byte
+	Hash       string
+	OutputPath string
+}
+
+func finalize(config Config, buf map[FileType]*bytes.Buffer) (map[FileType]*CompileResult, error) {
+	ret := make(map[FileType]*CompileResult, len(buf))
+
+	for key, b := range buf {
+		if b.Len() > 0 {
+			bytes := b.Bytes()
+			hash := sha256.Sum256(bytes)
+			ret[key] = &CompileResult{
+				Bytes: bytes,
+				Hash:  hex.EncodeToString(hash[:]),
+			}
+
+			if len(config.OutputDir) > 0 {
+				ext := "." + string(key)
+				if config.Minify {
+					ext = ".min" + ext
+				}
+				dir := filepath.Join(config.OutputDir, string(key))
+				os.MkdirAll(dir, os.ModeDir)
+				destFile := filepath.Join(dir, "app-"+ret[key].Hash+ext)
+				ret[key].OutputPath = destFile
+				ioutil.WriteFile(destFile, bytes, 0644)
+			}
+		}
+	}
+
+	return ret, nil
+}
+
+// Compile compiles files indicated by the config into a single file per type
+func Compile(config Config) (map[FileType]*CompileResult, error) {
+	var buf map[FileType]*bytes.Buffer
+	var err error
+	if buf, err = getBytes(config, initMinify()); err != nil {
+		return nil, err
+	}
+
+	return finalize(config, buf)
+}
+
+func supportedFileType(t FileType) bool {
+	switch t {
+	case CSS, JS:
+		return true
+	}
+
+	return false
+}
diff --git a/config.go b/config.go
new file mode 100644
index 0000000..39c1bee
--- /dev/null
+++ b/config.go
@@ -0,0 +1,8 @@
+package precompiler
+
+// Config holds information on how to run the compiler
+type Config struct {
+	Files     []string
+	Minify    bool
+	OutputDir string
+}
diff --git a/main.go b/main.go
new file mode 100644
index 0000000..5766193
--- /dev/null
+++ b/main.go
@@ -0,0 +1,23 @@
+package precompiler
+
+func main() {
+	Compile(Config{
+		Files: []string{
+			"assets/css/bootstrap.min.default.css",
+			"assets/css/font-awesome.min.css",
+			"assets/css/tempusdominus-bootstrap-4.min.css",
+			"assets/css/roboto.css",
+			"assets/css/application.css",
+			"assets/js/jquery.min.js",
+			"assets/js/popper.min.js",
+			"assets/js/bootstrap.min.js",
+			"assets/js/linkify.min.js",
+			"assets/js/linkify-jquery.min.js",
+			"assets/js/moment.min.js",
+			"assets/js/tempusdominus-bootstrap-4.min.js",
+			"assets/js/application.js",
+		},
+		Minify:    true,
+		OutputDir: "assets/",
+	})
+}