From 4a91b59942b14e4de87d09cc6101e518fab4711f Mon Sep 17 00:00:00 2001
From: Rohit-Karki <rohitkarki804@gmail.com>
Date: Thu, 30 Nov 2023 00:53:08 +0545
Subject: [PATCH] Compaction of stale files half completed

---
 compact.go | 99 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 header.go  |  2 +-
 ops.go     |  4 +--
 3 files changed, 102 insertions(+), 3 deletions(-)

diff --git a/compact.go b/compact.go
index 512237b..a10400b 100644
--- a/compact.go
+++ b/compact.go
@@ -1,2 +1,101 @@
 package bitcaspy
 
+import (
+	"fmt"
+	"os"
+	"time"
+
+	datafile "rohit.com/internal"
+)
+
+// checkFileSize delegates to rotateDf checks the file size for the mac file size
+// then places it into stale data files and creates a new data file
+func (b *BitCaspy) checkFileSize(evalInterval time.Duration) {
+	var (
+		evalTicker = time.NewTicker(evalInterval).C
+	)
+
+	for range evalTicker {
+		if err := b.rotateDf(); err != nil {
+			fmt.Errorf("failed to scan the active file: %v", err)
+		}
+	}
+}
+
+// rotateDf checks the file size for the mac file size
+// then places it into stale data files and creates a new data file
+func (b *BitCaspy) rotateDf() error {
+	b.Lock()
+	defer b.Unlock()
+
+	size, err := b.df.Size()
+	if err != nil {
+		return err
+	}
+
+	// If smaller than threshold no action
+	if size < 20000 {
+		return nil
+	}
+	oldId := b.df.ID()
+
+	b.stale[oldId] = b.df
+	newDf, err := datafile.New("rohit", oldId+1)
+	if err != nil {
+		return err
+	}
+	b.df = newDf
+	return nil
+}
+
+// Compacts the old stale data files
+func (b *BitCaspy) compaction(evalInterval time.Duration) {
+	var (
+		evalTicker = time.NewTicker(evalInterval).C
+	)
+	for range evalTicker {
+		b.Lock()
+
+		if err := b.deleteIfExpired(); err != nil {
+			fmt.Errorf("failed to delete the expired keys: %v", err)
+		}
+
+		// Merge the datafiles
+		if err := b.merge(); err != nil {
+
+		}
+
+	}
+}
+
+func (b *BitCaspy) deleteIfExpired() error {
+	// Iterate over all keys and delete all keys which are expired.
+	keyDir := b.KeyDir
+	for k := range keyDir {
+		record, err := b.get(k)
+		if err != nil {
+			fmt.Errorf("error %v", err)
+		}
+		if record.isExpired() {
+			if err := b.delete(k); err != nil {
+				return err
+			}
+		}
+	}
+	return nil
+}
+
+func (b *BitCaspy) merge() error {
+	// Create a new datafile for storing the output of merged files.
+	// Use a temp directory to store the file and move to main directory after merge is over.
+	tmpMergeDir, err := os.MkdirTemp("", "merged")
+	if err != nil {
+		return err
+	}
+
+	newFile, err := datafile.New(tmpMergeDir, 0)
+	if err != nil {
+		fmt.Errorf("Error creating new datafile: %v", err)
+	}
+
+}
diff --git a/header.go b/header.go
index f6e0084..3ea56c4 100644
--- a/header.go
+++ b/header.go
@@ -34,7 +34,7 @@ func (r *Record) isExpired() bool {
 	if r.Header.expiry == 0 {
 		return false
 	}
-	return int64(r.Header.expiry) < time.Now().Unix()  
+	return int64(r.Header.expiry) < time.Now().Unix()
 }
 
 func (r *Record) isValidChecksum() bool {
diff --git a/ops.go b/ops.go
index ef0c9ea..39dd533 100644
--- a/ops.go
+++ b/ops.go
@@ -98,8 +98,8 @@ func (b *BitCaspy) put(df *datafile.DataFile, Key string, Value []byte, expiryTi
 	return nil
 }
 
-func (b *BitCaspy) delete(df *datafile.DataFile, Key string) error {
-	if err := b.put(df, Key, nil, nil); err != nil {
+func (b *BitCaspy) delete(Key string) error {
+	if err := b.put(b.df, Key, nil, nil); err != nil {
 		return fmt.Errorf("Error deleting the key: %v", err)
 	}
 	delete(b.KeyDir, Key)