Start to move code into functions

This is the first step toward adding tests (#8).

mastobot.sh

@@ -11,9 +11,6 @@ MASTODON_TOKEN="ABCDefgh123456789x0x0x0x0x0x0x0x0x0x0x0"
 # The S3 bucket where your video clips are stored, including a trailing slash
 S3_BUCKET="s3://videobucket.amazonaws.com/directory/"
 
-# Get the name of the working directory
-cd "$(dirname "$0")" || exit
-
 # Define a failure function
 function exit_error {
     printf '%s\n' "$1" >&2
@@ -22,45 +19,83 @@ function exit_error {
     exit "${2-1}"
 }
 
-# Update the file listing 5% of the time
-if [ $(( $RANDOM % 20 + 1 )) -eq 1 ]; then
-	aws s3 ls ${S3_BUCKET} |grep -E -o "([0-9]+).m4v" > files.txt
-fi
+# Copy the video over from S3
+function get_video {
+    aws s3 cp "${S3_BUCKET}${ENTRY}" "$ENTRY" || return 1
+    return 0
+}
+
+# Add the clip to the history of filenames
+function add_to_history {
+    echo "$ENTRY" >> history.txt
+    return 0
+}
 
 # Store the total number of clips
-CLIP_COUNT=$(wc -l files.txt |cut -d " " -f 1)
+function get_clip_count {
+    wc -l files.txt |cut -d " " -f 1
+    return 0
+}
 
-# Select a clip, making sure that it hasn't been used recently
-while :
-do
+# Update the file listing 5% of the time, or generate it if it doesn't exist
+function update_file_list {
+    if [ ! -f ./files.txt ] || [ $(( RANDOM % 20 + 1 )) -eq 1 ]; then
+        aws s3 ls ${S3_BUCKET} |grep -E -o "([0-9]+).m4v" > files.txt
+        if [ $? -gt 0 ]; then
+            exit_error "Could not update file listing"
+        fi
+    fi
+    return 0
+}
 
-    # Select a random filename from the list
-    ENTRY=$(sort -R files.txt |head -1)
+# Select a clip, making sure that it hasn't been used recently
+function select_clip {
+    while :
+    do
+
+        # Select a random filename from the list
+        ENTRY=$(sort -R files.txt |head -1)
+
+        # Remove any trailing carriage return from the filename
+        ENTRY=$(echo "$ENTRY" | tr -d '\r')
+
+        # Ensure that the filename is a plausible length
+        if [ ${#ENTRY} -lt 5 ]; then
+            exit_error "Filename is too short"
+        fi
+
+        # Divide the total number of clips in half (n clips), and if this proposed clip hasn't been
+        # posted in the last n times, then proceed (otherwise, loop around again)
+        CLIP_HISTORY=$((CLIP_COUNT/2))
+        CLIP_HISTORY=$(printf "%.0f" $CLIP_HISTORY)
+        HISTORY=$(tail -"$CLIP_HISTORY" history.txt)
+        if [[ ! " ${HISTORY[*]} " =~ " ${ENTRY} " ]]; then
+            return 0
+        fi
+
+    done
+}
 
-    # Remove any trailing carriage return from the filename
-    ENTRY=$(echo "$ENTRY" | tr -d '\r')
+# Get the name of the working directory
+cd "$(dirname "$0")" || exit
 
-    # Ensure that the filename is a plausible length
-    if [ ${#ENTRY} -lt 5 ]; then
-        exit 1
-    fi
+# Update the file listing
+update_file_list
 
-    # Divide the total number of clips in half (n clips), and if this proposed clip hasn't been
-    # posted in the last n times, then proceed (otherwise, loop around again)
-    CLIP_HISTORY=$(($CLIP_COUNT/2))
-    CLIP_HISTORY=$(printf "%.0f" $CLIP_HISTORY)
-    HISTORY=$(tail -"$CLIP_HISTORY" history.txt)
-    if [[ ! " ${HISTORY[*]} " =~ " ${ENTRY} " ]]; then
-        break
-    fi    
-
-done
+# Store the total number of clips
+CLIP_COUNT=get_clip_count
 
-# Add this to the history of filenames
-echo "$ENTRY" >> history.txt
+# Select a clip
+select_clip
 
 # Copy the video over from S3
-aws s3 cp "${S3_BUCKET}${ENTRY}" "$ENTRY" || exit_error "Could not get video"
+get_video
+if [[ $? == 1 ]]; then
+    exit_error "Could not get video"
+fi
+
+# Add this clip's filename to the history
+add_to_history
 
 # Get the caption text
 ffmpeg -i "$ENTRY" -map 0:s:0 caption.srt