style(shell): prefer explicit conditionals for validation

Replace compact `[[ ... ]] || { ... }` guard blocks with explicit `if`
statements in config loading, preset loading, CLI argument validation,
size report helpers, and encode-file handling.

Rename the local preset variable in `load_preset` to `preset_name` for
clearer intent, and simplify the nice-value range check and size-report
summary default percentage handling.

No runtime behavior is intended to change.

1 files changed, 60 insertions, 54 deletions

diff --git a/transcode.sh b/transcode.sh
index 129ba88..3f317e6 100755
--- a/transcode.sh
+++ b/transcode.sh
@@ -477,13 +477,13 @@ load_config() {
   fi
 
   # We use -r and not -f to allow things like /dev/null
-  [[ -r "$CONFIG_FILE" ]] || {
+  if [[ ! -r "$CONFIG_FILE" ]]; then
     if [[ $_CLI_CONFIG_FILE -eq 1 ]]; then
       error "Config file not found:" "$CONFIG_FILE"
       exit $EXIT_CONFIG_ERROR
     fi
     return 0
-  }
+  fi
 
   command -v tomlq >/dev/null 2>&1 || {
     error "tomlq not found but $CONFIG_FILE exists. Install tomlq or remove the config file."
@@ -676,20 +676,21 @@ parse_skip_codec_parameter() {
 #     output_pixel_format, input_pixel_format, input_codec, input_frame_rate,
 #     input_fps, output_gop_size
 load_preset() {
-  local preset="$1"
-  # Strict allowlist: only alphanumerics, hyphens, and underscores are permitted.
-  # This prevents path traversal, shell metacharacter injection, and symlink-based
-  # attacks more reliably than a blocklist approach.
-  if [[ -z "$preset" || ! "$preset" =~ ^[a-zA-Z0-9_-]+$ ]]; then
-    error "Invalid preset name (only alphanumerics, hyphens, underscores allowed):" "$preset"
+  local preset_name="$1"
+
+  # Strict allowlist: only alphanumerics, hyphens, and underscores are
+  # permitted. This prevents path traversal, shell metacharacter injection, and
+  # symlink-based attacks more reliably than a blocklist approach.
+  if [[ -z "$preset_name" || ! "$preset_name" =~ ^[a-zA-Z0-9_-]+$ ]]; then
+    error "Invalid preset name (only alphanumerics, hyphens, underscores allowed):" "$preset_name"
     exit $EXIT_USAGE_ERROR
   fi
 
-  local file="$PRESET_DIR/$preset.sh"
-  [[ -f "$file" ]] || {
+  local file="$PRESET_DIR/$preset_name.sh"
+  if [[ ! -f "$file" ]]; then
     error "Preset not found:" "$file"
     exit $EXIT_CONFIG_ERROR
-  }
+  fi
 
   # Reject preset files that are world-writable to prevent arbitrary users from
   # injecting shell code.
@@ -716,10 +717,10 @@ load_preset() {
   # shellcheck source=/dev/null
   source "$file"
 
-  ((${#ffargs[@]})) || {
-    error "Preset '$preset' did not set ffargs"
+  if [[ ${#ffargs[@]} -eq 0 ]]; then
+    error "Preset '$preset_name' did not set ffargs"
     exit $EXIT_RUNTIME_FAILURE
-  }
+  fi
 
   debug "Preset ffargs:" "$(printf "%q " "${ffargs[@]}")"
 }
@@ -852,23 +853,23 @@ while [[ $# -gt 0 ]]; do
     shift
     ;;
   --config-file)
-    [[ $# -ge 2 ]] || {
+    if [[ $# -lt 2 ]]; then
       error "Missing value for $1"
       exit $EXIT_USAGE_ERROR
-    }
-    [[ -n "$2" ]] || {
+    fi
+    if [[ ! -n "$2" ]]; then
       error "Value for $1 must not be empty"
       exit $EXIT_USAGE_ERROR
-    }
+    fi
     CONFIG_FILE="$2"
     _CLI_CONFIG_FILE=1
     shift 2
     ;;
   --config-file=*)
-    [[ -n "${1#*=}" ]] || {
+    if [[ ! -n "${1#*=}" ]]; then
       error "Value for --config-file must not be empty"
       exit $EXIT_USAGE_ERROR
-    }
+    fi
     CONFIG_FILE="${1#*=}"
     _CLI_CONFIG_FILE=1
     shift
@@ -879,22 +880,22 @@ while [[ $# -gt 0 ]]; do
     shift
     ;;
   -f | --encode-file)
-    [[ $# -ge 2 ]] || {
+    if [[ $# -lt 2 ]]; then
       error "Missing value for $1"
       exit $EXIT_USAGE_ERROR
-    }
-    [[ -n "$2" ]] || {
+    fi
+    if [[ ! -n "$2" ]]; then
       error "Value for $1 must not be empty"
       exit $EXIT_USAGE_ERROR
-    }
+    fi
     ENCODE_FILE="$2"
     shift 2
     ;;
   --encode-file=*)
-    [[ -n "${1#*=}" ]] || {
+    if [[ ! -n "${1#*=}" ]]; then
       error "Value for --encode-file must not be empty"
       exit $EXIT_USAGE_ERROR
-    }
+    fi
     ENCODE_FILE="${1#*=}"
     shift
     ;;
@@ -903,10 +904,10 @@ while [[ $# -gt 0 ]]; do
     shift
     ;;
   -N | --nice)
-    [[ $# -ge 2 ]] || {
+    if [[ $# -lt 2 ]]; then
       error "Missing value for $1"
       exit $EXIT_USAGE_ERROR
-    }
+    fi
     NICE_VALUE="$2"
     _CLI_NICE=1
     shift 2
@@ -927,32 +928,32 @@ while [[ $# -gt 0 ]]; do
     shift
     ;;
   --size-report-file)
-    [[ $# -ge 2 ]] || {
+    if [[ $# -lt 2 ]]; then
       error "Missing value for $1"
       exit $EXIT_USAGE_ERROR
-    }
-    [[ -n "$2" ]] || {
+    fi
+    if [[ ! -n "$2" ]]; then
       error "Value for $1 must not be empty"
       exit $EXIT_USAGE_ERROR
-    }
+    fi
     SIZE_REPORT_FILE="$2"
     _CLI_SIZE_REPORT_FILE=1
     shift 2
     ;;
   --size-report-file=*)
-    [[ -n "${1#*=}" ]] || {
+    if [[ ! -n "${1#*=}" ]]; then
       error "Value for --size-report-file must not be empty"
       exit $EXIT_USAGE_ERROR
-    }
+    fi
     SIZE_REPORT_FILE="${1#*=}"
     _CLI_SIZE_REPORT_FILE=1
     shift
     ;;
   -S | --skip-codec)
-    [[ $# -ge 2 ]] || {
+    if [[ $# -lt 2 ]]; then
       error "Missing value for $1"
       exit $EXIT_USAGE_ERROR
-    }
+    fi
     parse_skip_codec_parameter "$2"
     shift 2
     ;;
@@ -986,10 +987,10 @@ while [[ $# -gt 0 ]]; do
   --hwaccel=*)
     HWACCEL=1
     HWACCEL_VALUE="${1#*=}"
-    [[ -n "$HWACCEL_VALUE" ]] || {
+    if [[ ! -n "$HWACCEL_VALUE" ]]; then
       error "Value for --hwaccel must not be empty"
       exit $EXIT_USAGE_ERROR
-    }
+    fi
     _CLI_HWACCEL=1
     shift
     ;;
@@ -999,23 +1000,23 @@ while [[ $# -gt 0 ]]; do
     shift
     ;;
   -p | --preset)
-    [[ $# -ge 2 ]] || {
+    if [[ $# -lt 2 ]]; then
       error "Missing value for $1"
       exit $EXIT_USAGE_ERROR
-    }
-    [[ -n "$2" ]] || {
+    fi
+    if [[ ! -n "$2" ]]; then
       error "Value for $1 must not be empty"
       exit $EXIT_USAGE_ERROR
-    }
+    fi
     PRESET_NAME="$2"
     _CLI_PRESET=1
     shift 2
     ;;
   --preset=*)
-    [[ -n "${1#*=}" ]] || {
+    if [[ ! -n "${1#*=}" ]]; then
       error "Value for --preset must not be empty"
       exit $EXIT_USAGE_ERROR
-    }
+    fi
     PRESET_NAME="${1#*=}"
     _CLI_PRESET=1
     shift
@@ -1075,7 +1076,7 @@ if [[ $_CLI_SIZE_REPORT_FILE -eq 1 && $SIZE_REPORT -eq 0 ]]; then
   warn "--size-report-file has no effect without --size-report"
 fi
 
-if [[ ! "$NICE_VALUE" =~ ^-?[0-9]+$ ]] || ((NICE_VALUE < -20 || NICE_VALUE > 19)); then
+if [[ ! "$NICE_VALUE" =~ ^-?[0-9]+$ || $NICE_VALUE -lt -20 || $NICE_VALUE -gt 19 ]]; then
   error "Invalid nice value (must be an integer between -20 and 19):" "$NICE_VALUE"
   exit $EXIT_USAGE_ERROR
 fi
@@ -1116,7 +1117,9 @@ calculate_saved_percentage() {
 # Empty byte/percentage fields are allowed for failures where no output size
 # exists.
 append_size_report_row() {
-  [[ $SIZE_REPORT -eq 1 && $DRY_RUN -eq 0 ]] || return $EXIT_OK
+  if [[ $SIZE_REPORT -ne 1 || $DRY_RUN -ne 0 ]]; then
+    return $EXIT_OK
+  fi
 
   local status="$1"
   local filename="$2"
@@ -1135,10 +1138,12 @@ append_size_report_row() {
   printf "%s\t%s\t%s\t%s\t%s\n" "$status" "$filename" "$original_bytes" "$new_bytes" "$saved_pct" >>"$SIZE_REPORT_FILE"
 }
 
-# Print per-file size feedback after an encode attempt that produced an output file.
+# Print per-file size feedback after an encode attempt that produced an output
+# file.
 print_size_report_feedback() {
-  [[ $SIZE_REPORT -eq 1 ]] || return $EXIT_OK
-
+  if [[ $SIZE_REPORT -eq 0 ]]; then
+    return $EXIT_OK
+  fi
   local status="$1"
   local original_bytes="$2"
   local new_bytes="$3"
@@ -1154,16 +1159,17 @@ print_size_report_feedback() {
 print_size_report_summary() {
   local amount_total_files="$1"
 
-  [[ $SIZE_REPORT -eq 1 && $QUIET -eq 0 && $amount_total_files -gt 1 ]] || return $EXIT_OK
+  if [[ $SIZE_REPORT -ne 1 || $QUIET -ne 0 || $amount_total_files -le 1 ]]; then
+    return $EXIT_OK
+  fi
 
   local skipped_total failed_total average_saved_pct
   skipped_total=$((_REPORT_SKIPPED_CODEC + _REPORT_SKIPPED_LARGER))
   failed_total=$((_REPORT_ENCODING_FAILED + _REPORT_INTEGRITY_FAILED))
+  average_saved_pct=0
 
   if [[ $_REPORT_TOTAL_ORIGINAL_BYTES -gt 0 ]]; then
     average_saved_pct=$((_REPORT_TOTAL_SAVED_BYTES * 100 / _REPORT_TOTAL_ORIGINAL_BYTES))
-  else
-    average_saved_pct=0
   fi
 
   printf "\n${BOLD}${BLUE}Size report summary:${ALL_OFF}\n"
@@ -1452,10 +1458,10 @@ encode_one() {
 
 STATUS=$EXIT_OK
 if [[ -n $ENCODE_FILE ]]; then
-  [[ -f "$ENCODE_FILE" ]] || {
+  if [[ ! -f "$ENCODE_FILE" ]]; then
     error "Encode file not found:" "$ENCODE_FILE"
     exit $EXIT_USAGE_ERROR
-  }
+  fi
   # Build the file list into an array first so we know the total count.
   mapfile -t FILES_TO_ENCODE < <(
     while IFS= read -r file || [[ -n "$file" ]]; do