Allow completely non-embedded builds

This enables installs straight from 'go install' or 'fyne install'. It
also means warning if a system getgbook isn't found, and erroring if
tesseract isn't found (as was done already). The location of getgbook
can therefore now be specified on the command line.

Embedded builds are enabled with the -tags embed flag, which the makefile
sets for all builds.

1 files changed, 42 insertions, 28 deletions

diff --git a/cmd/rescribe/main.go b/cmd/rescribe/main.go
index fd5b33b..16ca024 100644
--- a/cmd/rescribe/main.go
+++ b/cmd/rescribe/main.go
@@ -13,7 +13,6 @@ import (
 	"archive/zip"
 	"bytes"
 	"context"
-	_ "embed"
 	"flag"
 	"fmt"
 	"image/jpeg"
@@ -35,7 +34,7 @@ import (
 	"rescribe.xyz/utils/pkg/hocr"
 )
 
-const usage = `Usage: rescribe [-v] [-gui] [-systess] [-tesscmd] [-t training] bookdir/book.pdf [savedir]
+const usage = `Usage: rescribe [-v] [-gui] [-systess] [-tesscmd cmd] [-gbookcmd cmd] [-t training] bookdir/book.pdf [savedir]
 
 Process and OCR a book using the Rescribe pipeline on a local machine.
 
@@ -43,9 +42,6 @@ OCR results are saved into the bookdir directory unless savedir is
 specified.
 `
 
-//go:embed tessdata.20220322.zip
-var tessdatazip []byte
-
 const QueueTimeoutSecs = 2 * 60
 const PauseBetweenChecks = 1 * time.Second
 const LogSaveTime = 1 * time.Minute
@@ -95,7 +91,7 @@ func resetTimer(t *time.Timer, d time.Duration) {
 	}
 }
 
-// unpackTessZip unpacks a byte array of a zip file into a directory
+// unpackZip unpacks a byte array of a zip file into a directory
 func unpackZip(b []byte, dir string) error {
 	br := bytes.NewReader(b)
 	zr, err := zip.NewReader(br, br.Size())
@@ -140,8 +136,10 @@ func unpackZip(b []byte, dir string) error {
 
 func main() {
 	deftesscmd := "tesseract"
+	defgbookcmd := "getgbook"
 	if runtime.GOOS == "windows" {
 		deftesscmd = "C:\\Program Files\\Tesseract-OCR\\tesseract.exe"
+		defgbookcmd = "getgbook.exe"
 	}
 
 	verbose := flag.Bool("v", false, "verbose")
@@ -153,6 +151,7 @@ These training files are included in rescribe, and are always available:
 - lat.traineddata (Latin, modern print)
 - rescribev9_fast.traineddata (Latin/English/French, printed ca 1500-1800)
 	`)
+	gbookcmd := flag.String("gbookcmd", defgbookcmd, "The getgbook executable to run. You may need to set this to the full path of getgbook.exe if you're on Windows.")
 	tesscmd := flag.String("tesscmd", deftesscmd, "The Tesseract executable to run. You may need to set this to the full path of Tesseract.exe if you're on Windows.")
 	wipe := flag.Bool("wipe", false, "Use wiper tool to remove noise like gutters from page before processing.")
 	fullpdf := flag.Bool("fullpdf", false, "Use highest image quality for searchable PDF (requires lots of RAM).")
@@ -187,7 +186,7 @@ These training files are included in rescribe, and are always available:
 		log.Fatalln("Error setting up tesseract directory:", err)
 	}
 
-	if !*systess {
+	if !*systess && len(tesszip) > 0 {
 		err = unpackZip(tesszip, tessdir)
 		if err != nil {
 			log.Fatalln("Error unpacking embedded Tesseract zip:", err)
@@ -202,18 +201,31 @@ These training files are included in rescribe, and are always available:
 		}
 	}
 
-	err = unpackZip(gbookzip, tessdir)
+	_, err = exec.LookPath(tessCommand)
 	if err != nil {
-		log.Fatalln("Error unpacking embedded getgbook zip:", err)
+		log.Fatalf("No tesseract executable found [tried %s], either set -tesscmd and -systess on the command line or use the official build which includes an embedded copy of Tesseract.", tessCommand)
+	}
+
+	gbookCommand := *gbookcmd
+	if len(gbookzip) > 0 {
+		err = unpackZip(gbookzip, tessdir)
+		if err != nil {
+			log.Fatalln("Error unpacking embedded getgbook zip:", err)
+		}
+		switch runtime.GOOS {
+		case "darwin":
+			gbookCommand = filepath.Join(tessdir, "getgbook")
+		case "linux":
+			gbookCommand = filepath.Join(tessdir, "getgbook")
+		case "windows":
+			gbookCommand = filepath.Join(tessdir, "getgbook.exe")
+		}
 	}
-	var gbookCommand string
-	switch runtime.GOOS {
-	case "darwin":
-		gbookCommand = filepath.Join(tessdir, "getgbook")
-	case "linux":
-		gbookCommand = filepath.Join(tessdir, "getgbook")
-	case "windows":
-		gbookCommand = filepath.Join(tessdir, "getgbook.exe")
+
+	_, err = exec.LookPath(gbookCommand)
+	if err != nil {
+		log.Printf("No getgbook found [tried %s], google book downloading will be disabled, either set -gbookcmd on the command line or use the official build which includes an embedded getgbook.", gbookCommand)
+		gbookCommand = ""
 	}
 
 	tessdatadir := filepath.Join(tessdir, "tessdata")
@@ -221,9 +233,11 @@ These training files are included in rescribe, and are always available:
 	if err != nil {
 		log.Fatalln("Error setting up tessdata directory:", err)
 	}
-	err = unpackZip(tessdatazip, tessdatadir)
-	if err != nil {
-		log.Fatalln("Error unpacking embedded tessdata zip:", err)
+	if len(tessdatazip) > 0 {
+		err = unpackZip(tessdatazip, tessdatadir)
+		if err != nil {
+			log.Fatalln("Error unpacking embedded tessdata zip:", err)
+		}
 	}
 
 	// if trainingPath doesn't exist, set it to the embedded training instead
@@ -233,14 +247,6 @@ These training files are included in rescribe, and are always available:
 		trainingPath = filepath.Join(tessdatadir, trainingPath)
 	}
 
-	f, err := os.Open(trainingPath)
-	if err != nil {
-		fmt.Fprintf(os.Stderr, "Error: Training files %s or %s could not be opened.\n", *training, trainingPath)
-		fmt.Fprintf(os.Stderr, "Set the `-t` flag with path to a tesseract .traineddata file.\n")
-		os.Exit(1)
-	}
-	f.Close()
-
 	abstraining, err := filepath.Abs(trainingPath)
 	if err != nil {
 		log.Fatalf("Error getting absolute path of training %s: %v", trainingPath, err)
@@ -265,6 +271,14 @@ These training files are included in rescribe, and are always available:
 		return
 	}
 
+	f, err := os.Open(trainingPath)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "Error: Training files %s or %s could not be opened.\n", *training, trainingPath)
+		fmt.Fprintf(os.Stderr, "Set the `-t` flag with path to a tesseract .traineddata file.\n")
+		os.Exit(1)
+	}
+	f.Close()
+
 	bookdir := flag.Arg(0)
 	bookname := strings.ReplaceAll(filepath.Base(bookdir), " ", "_")
 	savedir := bookdir