Fish shell script to create m4b-tool metadata from Libby audiobook metadata

libby-parse.fish

#!/usr/bin/env fish

# Check if jq is installed
if not command -v jq &> /dev/null
    echo "Error: jq is required but not installed. Please install it first."
    exit 1
end

# Check if metadata.json exists in ./metadata/
if not test -f ./metadata/metadata.json
    echo "Error: ./metadata/metadata.json not found"
    exit 1
end

set -l metadata_file ./metadata/metadata.json

# Extract book title
set -g booktitle (jq -r '.title' $metadata_file)
echo "Fish variable booktitle set to \"$booktitle\""

# Extract authors (only creators with role "author")
set -l authors (jq -r '.creator[] | select(.role == "author") | .name' $metadata_file)
set -g author (string join ", " $authors)
echo "Fish variable author set to \"$author\""

# Look up publication year using Open Library API
echo "Looking up publication year..."
set -l search_query (string escape --style=url "$booktitle $author")
set -l api_response (curl -s "https://openlibrary.org/search.json?q=$search_query&limit=1")

set -l pub_year (echo $api_response | jq -r '.docs[0].first_publish_year // empty')

if test -n "$pub_year"
    set -g year $pub_year
    echo "Fish variable year set to \"$year\""
else
    echo "No publication year found - variable year not set"
end

# Extract description and create description.txt
# Remove HTML tags and decode HTML entities, preserving line breaks
jq -r '.description.full' $metadata_file | \
    sed 's/<br>/\n/g' | \
    sed 's/<\/p>/\n\n/g' | \
    sed 's/<p>//g' | \
    sed 's/<[^>]*>//g' | \
    sed 's/&nbsp;/ /g' | \
    sed 's/&lt;/</g' | \
    sed 's/&gt;/>/g' | \
    sed 's/&amp;/\&/g' | \
    sed 's/&quot;/"/g' | \
    sed "s/&apos;/'/g" | \
    sed 's/Â/ /g' > description.txt
echo "Created description.txt"

# Process chapters and create chapters.txt
set -l chapters_output ""

# Get chapters array
set -l chapters (jq -c '.chapters[]' $metadata_file)

for chapter in $chapters
    set -l title (echo $chapter | jq -r '.title')
    set -l spine_index (echo $chapter | jq -r '.spine')
    set -l offset (echo $chapter | jq -r '.offset')
    
    # Calculate cumulative duration up to this spine
    set -l cumulative_seconds 0
    
    # Sum durations of all previous spine entries
    if test $spine_index -gt 0
        for i in (seq 0 (math $spine_index - 1))
            set -l duration (jq -r ".spine[$i].duration" $metadata_file)
            set cumulative_seconds (math $cumulative_seconds + $duration)
        end
    end
    
    # Add the offset within the current spine
    set cumulative_seconds (math $cumulative_seconds + $offset)
    
    # Convert to hours:minutes:seconds.milliseconds
    set -l hours (math -s0 "floor($cumulative_seconds / 3600)")
    set -l minutes (math -s0 "floor(($cumulative_seconds % 3600) / 60)")
    set -l seconds (math -s0 "floor($cumulative_seconds % 60)")
    set -l milliseconds (math -s0 "floor(($cumulative_seconds - floor($cumulative_seconds)) * 1000)")
    
    # Format timestamp
    set -l timestamp (printf "%02d:%02d:%02d.%03d" $hours $minutes $seconds $milliseconds)
    
    # Append to output
    set chapters_output "$chapters_output$timestamp $title\n"
end

# Write chapters.txt
printf $chapters_output > chapters.txt
echo "Created chapters.txt"