From c12c5f9df91fbd5962cbfae8dfef76bd73af2cde Mon Sep 17 00:00:00 2001
From: stephen mcquay <stephen@mcquay.me>
Date: Sun, 15 May 2016 22:51:52 -0700
Subject: [PATCH] init

---
 main.go | 144 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 144 insertions(+)
 create mode 100644 main.go

diff --git a/main.go b/main.go
new file mode 100644
index 0000000..bd5921e
--- /dev/null
+++ b/main.go
@@ -0,0 +1,144 @@
+package main
+
+import (
+	"crypto/md5"
+	"fmt"
+	"io"
+	"log"
+	"os"
+	"path/filepath"
+	"strings"
+	"sync"
+)
+
+const usage = "picmv <indir> <outdir>"
+
+type input struct {
+	path string
+	hash string
+	ext  string
+}
+
+type stats struct {
+	total int
+	moved int
+}
+
+func main() {
+	if len(os.Args) != 3 {
+		fmt.Fprintf(os.Stderr, "%s\n", usage)
+		os.Exit(1)
+	}
+	in, out := os.Args[1], os.Args[2]
+	log.Printf("%+v", in)
+
+	for i := 0; i <= 0xff; i++ {
+		dirname := filepath.Join(out, fmt.Sprintf("%02x", i))
+		os.MkdirAll(dirname, 0755)
+	}
+
+	st := stats{}
+
+	work := source(in)
+	res := []<-chan input{}
+	for w := 0; w < 16; w++ {
+		res = append(res, compute(work))
+	}
+
+	for in := range merge(res) {
+		if in.ext != ".jpg" {
+			log.Printf("%+v", in)
+		}
+		st.total++
+		finalDest := filepath.Join(out, in.hash[:2], in.hash[2:]+in.ext)
+		if _, err := os.Stat(finalDest); !os.IsNotExist(err) {
+			log.Printf("dup detected: %+v", in)
+			continue
+		}
+		if err := os.Link(in.path, finalDest); err != nil {
+			log.Printf("%+v", err)
+		}
+		st.moved++
+	}
+	log.Printf("total files moved     : %d", st.moved)
+	log.Printf("total files processed : %d", st.total)
+}
+
+func source(root string) <-chan string {
+	out := make(chan string)
+	go func() {
+		err := filepath.Walk(
+			root,
+			func(path string, info os.FileInfo, err error) error {
+				if info.IsDir() {
+					return nil
+				}
+				out <- path
+				return nil
+			},
+		)
+		if err != nil {
+			log.Printf("problem from crawling root %q: %+v", root, err)
+		}
+		close(out)
+	}()
+	return out
+}
+
+func compute(work <-chan string) <-chan input {
+	out := make(chan input)
+	go func() {
+		for path := range work {
+			h, err := _hash(path)
+			if err != nil {
+				log.Printf("problem hashing: %+v", err)
+				continue
+			}
+			out <- h
+		}
+		close(out)
+	}()
+	return out
+}
+
+func merge(cs []<-chan input) <-chan input {
+	out := make(chan input)
+	var wg sync.WaitGroup
+
+	output := func(c <-chan input) {
+		for n := range c {
+			out <- n
+		}
+		wg.Done()
+	}
+
+	for _, c := range cs {
+		go output(c)
+	}
+
+	wg.Add(len(cs))
+
+	go func() {
+		wg.Wait()
+		close(out)
+	}()
+	return out
+}
+
+func _hash(path string) (input, error) {
+	f, err := os.Open(path)
+	if err != nil {
+		return input{}, fmt.Errorf("problem opening file: %v", err)
+	}
+	defer f.Close()
+	hash := md5.New()
+	if _, err := io.Copy(hash, f); err != nil {
+		return input{}, fmt.Errorf("problem calculating hash for %q: %+v", path, err)
+	}
+	r := input{
+		path: path,
+		hash: fmt.Sprintf("%x", hash.Sum(nil)),
+		ext:  strings.ToLower(filepath.Ext(path)),
+	}
+	return r, nil
+}