1 files changed, 126 insertions, 0 deletions
diff --git a/files/database.go b/files/database.go
new file mode 100644
index 0000000..24bd5af
--- /dev/null
+++ b/files/database.go
@@ -0,0 +1,126 @@
+package files
+
+import (
+	"context"
+	"crypto/sha256"
+	"encoding/json"
+	"fmt"
+	"io"
+	"io/fs"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"regexp"
+	"strings"
+
+	"github.com/tidwall/buntdb"
+)
+
+func evaluateFile(database *buntdb.DB, hashsum string, filedata FileInfo) error {
+	return database.View(func(tx *buntdb.Tx) error {
+		data, err := tx.Get(hashsum)
+		if err != nil {
+			return err
+		}
+
+		var info FileInfo
+		if err := json.Unmarshal([]byte(data), &info); err != nil {
+			return err
+		}
+		if info == filedata {
+			return UpToDate
+		}
+		switch info.Modtime == filedata.Modtime {
+		case true:
+			if info.AbsPath == filedata.AbsPath {
+				if info.Process {
+					return NeedsReencode
+				}
+				return UpToDate
+			}
+			if info.Process {
+				return NeedsReencode
+			}
+			return MovedFile
+		default:
+			return nil
+		}
+	})
+}
+
+func getEncoderVer(path string) (string, error) {
+	out, err := exec.Command("metaflac", "--show-vendor-tag", path).Output()
+	if err != nil {
+		return "", err
+	}
+
+	r := regexp.MustCompile("libFLAC \\d\\.\\d\\.\\d")
+	encoder := r.FindString(string(out))
+	switch encoder {
+	case "":
+		return "", nil
+	default:
+		return strings.Split(encoder, " ")[1], nil
+	}
+}
+
+func updateFile(database *buntdb.DB, hashsum string, filedata FileInfo) error {
+	return database.Update(func(tx *buntdb.Tx) error {
+		data, err := json.Marshal(filedata)
+		if err != nil {
+			return err
+		}
+		if _, _, err := tx.Set(hashsum, string(data), nil); err != nil {
+			return err
+		}
+		return nil
+	})
+}
+
+func ProcessFile(ctx context.Context, path string, info fs.DirEntry) error {
+	tmp, err := info.Info()
+	if err != nil {
+		return err
+	}
+
+	modtime := tmp.ModTime()
+
+	database := ctx.Value("database").(*buntdb.DB)
+
+	file, err := os.Open(path)
+	if err != nil {
+		return err
+	}
+	defer file.Close()
+
+	hash := sha256.New()
+	if _, err := io.Copy(hash, file); err != nil {
+		return err
+	}
+	hashsum := fmt.Sprintf("%x", hash.Sum(nil))
+
+	abspath, err := filepath.Abs(path)
+	if err != nil {
+		return err
+	}
+
+	encoder, err := getEncoderVer(path)
+
+	filedata := FileInfo{AbsPath: abspath, Modtime: modtime, Encoder: encoder, Process: true}
+
+	err = evaluateFile(database, hashsum, filedata)
+	switch err {
+	case MovedFile, UpToDate:
+		if filedata.Encoder == ctx.Value("encoder").(string) {
+			return nil
+		}
+	case buntdb.ErrNotFound, NeedsReencode:
+
+	default:
+		return err
+	}
+	if err := updateFile(database, hashsum, filedata); err != nil {
+		return err
+	}
+	return nil
+}