#!/bin/bash

# Default URL of the Twtxt feed
DEFAULT_FEED_URL="https://twtxt.net/user/prologic/twtxt.txt"

# If a URL is passed as the first argument, use it; otherwise, use the default
FEED_URL="${1:-$DEFAULT_FEED_URL}"

OUTPUT_FILE="output.txt"
MODIFIED_FILE="modified_output.txt"

# Fetch the last 100 lines of the feed and extract Twt Subjects
curl -s "$FEED_URL" | tail -n 100 > "$OUTPUT_FILE"

# Loop through each line, find the Twt Subject, and replace with twter.url + created timestamp
while IFS= read -r line; do
    # Extract the Twt Subject using grep and regex
    SUBJECT=$(echo "$line" | grep -oP '\(#\K\w+')

    if [[ -n "$SUBJECT" ]]; then
        # Curl the JSON data for the corresponding Twt Subject
        JSON_DATA=$(curl -s -H "Accept: application/json" "https://twtxt.net/twt/$SUBJECT")

        # Check if the JSON data is valid
        if echo "$JSON_DATA" | jq empty 2>/dev/null; then
            # Extract the twter URL and created timestamp from the JSON response
            TWTER_URL=$(echo "$JSON_DATA" | jq -r '.twter.uri // empty')
            CREATED_TIMESTAMP=$(echo "$JSON_DATA" | jq -r '.created // empty')

            # Only process the line if both twter.url and created are valid
            if [[ -n "$TWTER_URL" && -n "$CREATED_TIMESTAMP" ]]; then
                # Build the replacement string
                REPLACEMENT="($TWTER_URL $CREATED_TIMESTAMP)"

                # Replace the Twt Subject in the line manually using Bash string manipulation
                MODIFIED_LINE="${line//(#$SUBJECT)/$REPLACEMENT}"

                # Append the modified line to the modified output file
                echo "$MODIFIED_LINE" >> "$MODIFIED_FILE"
            else
                # If no valid data, copy the line as is
                echo "$line" >> "$MODIFIED_FILE"
            fi
        else
            # If invalid JSON, copy the line as is
            echo "$line" >> "$MODIFIED_FILE"
        fi
    else
        # If no subject found, copy the line as is
        echo "$line" >> "$MODIFIED_FILE"
    fi
done < "$OUTPUT_FILE"

# Compare the file sizes
ORIGINAL_SIZE=$(stat --format="%s" "$OUTPUT_FILE")
MODIFIED_SIZE=$(stat --format="%s" "$MODIFIED_FILE")

# Calculate percentage increase
SIZE_DIFF=$((MODIFIED_SIZE - ORIGINAL_SIZE))
PERCENT_INCREASE=$(awk "BEGIN {printf \"%.2f\", ($SIZE_DIFF / $ORIGINAL_SIZE) * 100}")

# Display file sizes and percentage increase
echo "Original file size: $ORIGINAL_SIZE bytes"
echo "Modified file size: $MODIFIED_SIZE bytes"
echo "Percentage increase in file size: $PERCENT_INCREASE%"

# Extract and display the last lines of both files
echo -e "\nLast line of the original file:"
ORIGINAL_LAST_LINE=$(tail -n 1 "$OUTPUT_FILE")
echo "$ORIGINAL_LAST_LINE"

echo -e "\nLast line of the modified file:"
MODIFIED_LAST_LINE=$(tail -n 1 "$MODIFIED_FILE")
echo "$MODIFIED_LAST_LINE"

# Use diff to show a colorized diff of the last lines
echo -e "\nColorized diff of the last line:"
diff --color=always <(echo "$ORIGINAL_LAST_LINE") <(echo "$MODIFIED_LAST_LINE") || true