From de9d5f0945917eb09406d94eaa2bbf9773a8d137 Mon Sep 17 00:00:00 2001
From: Amir Aref <amiraref808@gmail.com>
Date: Thu, 23 Apr 2026 21:48:44 +0330
Subject: [PATCH] refactor reduce_bitrate script for improved logging and
 functionality

add .gitignore for mp3 and bak files;
---
 .gitignore        |   2 +
 reduce_bitrate.sh | 215 +++++++++++++++++++++++++++++++++-------------
 2 files changed, 159 insertions(+), 58 deletions(-)
 create mode 100644 .gitignore

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..7333585
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,2 @@
+*.mp3
+*.bak
\ No newline at end of file
diff --git a/reduce_bitrate.sh b/reduce_bitrate.sh
index 4b4aab9..8e53b17 100755
--- a/reduce_bitrate.sh
+++ b/reduce_bitrate.sh
@@ -1,81 +1,180 @@
-#!/bin/bash
+#!/usr/bin/env bash
 
-# Define the target bitrate
 TARGET_BITRATE="192k"
+ROOT_DIR="."
+DRY_RUN=0
+CLEANUP_BACKUPS=0
 
-echo -e "\n\033[1;32mStarting Bitrate Reduction Script...\033[0m"
-echo -e "\033[1;34mTarget Bitrate: \033[0m${TARGET_BITRATE}"
+GREEN="\033[1;32m"
+BLUE="\033[1;34m"
+YELLOW="\033[1;33m"
+RED="\033[1;31m"
+DIM="\033[2m"
+RESET="\033[0m"
 
-# Function to process MP3 files safely
-process_directory() {
-    local DIR="$1"
-    echo "Scanning Directory: $DIR"
+usage() {
+    echo -e "${BLUE}Usage:${RESET} $0 [-n] [-d DIR] [-c]"
+    echo -e "  -n        Dry-run (only show files that would be converted)"
+    echo -e "  -d DIR    Working directory (default: current directory)"
+    echo -e "  -c        Remove .bak files after successful run"
+    echo -e "  -h        Show this help"
+}
 
-    # Use find with -print0 + read -d '' → null-separated = safe with any filename
-    while IFS= read -r -d '' file; do
-        echo "Processing: $file"
+log_step() { echo -e "\n${BLUE}▶${RESET} $*"; }
+log_info() { echo -e "${BLUE}ℹ${RESET}  $*"; }
+log_warn() { echo -e "${YELLOW}⚠${RESET}  $*"; }
+log_error() { echo -e "${RED}✖${RESET}  $*"; }
+log_success() { echo -e "${GREEN}✔${RESET}  $*"; }
 
-        # Get current bitrate
-        METADATA=$(ffprobe -v error -select_streams a:0 -show_entries stream=bit_rate \
+get_total_size_mb() {
+    local dir="$1"
+    find "$dir" -name "*.mp3" -print0 | xargs -0 stat -c '%s' 2>/dev/null | \
+        awk '{sum += $1} END {printf "%.2f MB\n", sum/1024/1024}'
+}
+
+get_bitrate_kbps() {
+    local file="$1"
+    local metadata
+
+    metadata=$(ffprobe -v error -select_streams a:0 -show_entries stream=bit_rate \
+        -of default=noprint_wrappers=1:nokey=1 "$file" < /dev/null 2>/dev/null)
+
+    if ! [[ "$metadata" =~ ^[0-9]+$ ]]; then
+        metadata=$(ffprobe -v error -show_entries format=bit_rate \
             -of default=noprint_wrappers=1:nokey=1 "$file" < /dev/null 2>/dev/null)
+    fi
 
-        if ! [[ "$METADATA" =~ ^[0-9]+$ ]]; then
-            METADATA=$(ffprobe -v error -show_entries format=bit_rate \
-                -of default=noprint_wrappers=1:nokey=1 "$file" < /dev/null 2>/dev/null)
-        fi
+    if [[ "$metadata" =~ ^[0-9]+$ ]]; then
+        echo $((metadata / 1024))
+        return 0
+    fi
 
-        if ! [[ "$METADATA" =~ ^[0-9]+$ ]]; then
-            echo -e "\033[1;31mError:\033[0m Could not read bit rate for $file. Skipping."
-            continue
-        fi
+    return 1
+}
 
-        CURRENT_BITRATE=$((METADATA / 1024))
-        echo -e "\033[1;32mCurrent Bitrate:\033[0m ${CURRENT_BITRATE} kbps"
+process_file() {
+    local file="$1"
+    local current_bitrate
+    local backup_file
+    local temp_file
 
-        if [ "$CURRENT_BITRATE" -le "${TARGET_BITRATE%k}" ]; then
-            echo -e "\033[1;33mInfo:\033[0m Already at or below target. Skipping."
-            continue
-        fi
+    current_bitrate=$(get_bitrate_kbps "$file") || {
+        log_warn "Could not read bitrate for: ${file}"
+        ((warn_count++))
+        return 0
+    }
 
-        # Create backup
-        BACKUP_FILE="${file%.mp3}.bak"
-        if [ ! -f "$BACKUP_FILE" ]; then
-            cp "$file" "$BACKUP_FILE"
-            echo -e "\033[1;32mBackup created:\033[0m $BACKUP_FILE"
-        fi
+    if [ "$current_bitrate" -le "${TARGET_BITRATE%k}" ]; then
+        log_info "Skip (already <= ${TARGET_BITRATE}): ${file}"
+        ((skip_count++))
+        return 0
+    fi
 
-        # Convert safely using a temporary file with full path
-        TEMP_FILE="${file%.mp3}_temp_$$.mp3"
+    if [ "$DRY_RUN" -eq 1 ]; then
+        log_info "Would convert (${current_bitrate} kbps ➜ ${TARGET_BITRATE}): ${file}"
+        ((dry_run_count++))
+        return 0
+    fi
 
-        if ffmpeg -nostdin -y -i "$file" -b:a "${TARGET_BITRATE}" -id3v2_version 3 "$TEMP_FILE" > /dev/null 2>&1; then
-            mv "$TEMP_FILE" "$file"
-            echo -e "\033[1;32mProcessed \033[0m$file \033[1;32mto ${TARGET_BITRATE} ✅\033[0m"
-        else
-            echo -e "\033[1;31mError:\033[0m ffmpeg failed for $file"
-            rm -f "$TEMP_FILE"
-        fi
+    backup_file="${file%.mp3}.bak"
+    if [ ! -f "$backup_file" ]; then
+        cp "$file" "$backup_file"
+        log_success "Backup created: ${backup_file}"
+    fi
 
-    done < <(find "$DIR" -maxdepth 1 -type f -name "*.mp3" -print0)
+    temp_file="${file%.mp3}_temp_$$.mp3"
+    if ffmpeg -nostdin -y -i "$file" -b:a "${TARGET_BITRATE}" -id3v2_version 3 "$temp_file" > /dev/null 2>&1; then
+        mv "$temp_file" "$file"
+        log_success "Converted: ${file} (${current_bitrate} kbps ➜ ${TARGET_BITRATE}) ✅"
+        ((converted_count++))
+    else
+        rm -f "$temp_file"
+        log_error "ffmpeg failed: ${file}"
+        ((error_count++))
+    fi
 }
 
 # ==================== MAIN ====================
 
-# Calculate total size before
-TOTAL_SIZE_BEFORE=$(find . -name "*.mp3" -print0 | xargs -0 stat -c '%s' 2>/dev/null | \
-                    awk '{sum += $1} END {printf "%.2f MB\n", sum/1024/1024}')
-echo -e "\n\033[1;32mTotal MP3 size before:\033[0m ${TOTAL_SIZE_BEFORE:-0.00 MB}"
+while getopts ":nd:ch" opt; do
+    case "$opt" in
+        n) DRY_RUN=1 ;;
+        d) ROOT_DIR="$OPTARG" ;;
+        c) CLEANUP_BACKUPS=1 ;;
+        h)
+            usage
+            exit 0
+            ;;
+        *)
+            usage
+            exit 1
+            ;;
+    esac
+done
 
-# Process every directory (including .)
-while IFS= read -r -d '' dir; do
-    process_directory "$dir"
-done < <(find . -type d -print0)
+if ! command -v ffprobe >/dev/null 2>&1 || ! command -v ffmpeg >/dev/null 2>&1; then
+    log_error "ffprobe/ffmpeg not found. Please install ffmpeg." 
+    exit 1
+fi
 
-# Calculate total size after
-TOTAL_SIZE_AFTER=$(find . -name "*.mp3" -print0 | xargs -0 stat -c '%s' 2>/dev/null | \
-                   awk '{sum += $1} END {printf "%.2f MB\n", sum/1024/1024}')
+if [ ! -d "$ROOT_DIR" ]; then
+    log_error "Directory not found: ${ROOT_DIR}"
+    exit 1
+fi
 
-echo -e "\n\033[1;32mTotal MP3 size after:\033[0m ${TOTAL_SIZE_AFTER:-0.00 MB}"
-echo -e "\n\033[1;32mBitrate Reduction Script Complete! 🎉\033[0m"
+log_step "Starting Bitrate Reduction"
+log_info "Target bitrate: ${TARGET_BITRATE}"
+log_info "Working directory: ${ROOT_DIR}"
+if [ "$DRY_RUN" -eq 1 ]; then
+    log_info "Dry-run: enabled"
+fi
+if [ "$CLEANUP_BACKUPS" -eq 1 ]; then
+    log_info "Cleanup backups: enabled"
+fi
 
-# Optional: remove all .bak files at the end
-# find . -name "*.bak" -type f -delete
+total_before=$(get_total_size_mb "$ROOT_DIR")
+log_info "Total MP3 size before: ${total_before:-0.00 MB}"
+
+converted_count=0
+skip_count=0
+warn_count=0
+error_count=0
+dry_run_count=0
+file_count=0
+
+log_step "Scanning for MP3 files..."
+while IFS= read -r -d '' file; do
+    ((file_count++))
+    process_file "$file"
+done < <(find "$ROOT_DIR" -type f -name "*.mp3" -print0)
+
+if [ "$file_count" -eq 0 ]; then
+    log_warn "No MP3 files found in ${ROOT_DIR}"
+fi
+
+total_after=$(get_total_size_mb "$ROOT_DIR")
+log_info "Total MP3 size after: ${total_after:-0.00 MB}"
+
+log_step "Summary"
+log_info "Files scanned: ${file_count}"
+log_info "Converted: ${converted_count}"
+log_info "Skipped: ${skip_count}"
+log_info "Dry-run matches: ${dry_run_count}"
+log_info "Warnings: ${warn_count}"
+if [ "$error_count" -gt 0 ]; then
+    log_error "Errors: ${error_count}"
+else
+    log_success "Errors: 0"
+fi
+
+if [ "$CLEANUP_BACKUPS" -eq 1 ] && [ "$DRY_RUN" -eq 0 ] && [ "$error_count" -eq 0 ]; then
+    log_step "Cleaning up backups"
+    find "$ROOT_DIR" -name "*.bak" -type f -delete
+    log_success "All .bak files removed"
+elif [ "$CLEANUP_BACKUPS" -eq 1 ] && [ "$DRY_RUN" -eq 1 ]; then
+    log_warn "Cleanup skipped in dry-run mode"
+elif [ "$CLEANUP_BACKUPS" -eq 1 ] && [ "$error_count" -gt 0 ]; then
+    log_warn "Cleanup skipped due to errors"
+fi
+
+log_step "Done 🎉"