Get average and median lifetimes of merged Pull Requests using the gh CLI

pr_lifetimes.sh

#!/bin/bash

REPO=Go-Electra/electra-backend

prs=$(gh pr list --state merged --repo $REPO --json createdAt,mergedAt --limit 100)

count=0
total=0
lifetimes=()

for pr in $(echo "${prs}" | jq -c '.[]'); do
  created=$(echo $pr | jq -r '.createdAt')
  merged=$(echo $pr | jq -r '.mergedAt')

  # Convert the dates to seconds since the Unix epoch
  created_seconds=$(date -j -f "%Y-%m-%dT%H:%M:%SZ" "$created" +"%s")
  merged_seconds=$(date -j -f "%Y-%m-%dT%H:%M:%SZ" "$merged" +"%s")

  # Calculate the difference in secs
  diff=$((merged_seconds - created_seconds))
  
  # Add to totals
  total=$((total + diff))
  count=$((count + 1))
  lifetimes+=($diff)
done

# Calculate and print the median
# Sort the lifetimes array
IFS=$'\n' sorted=($(sort -n <<<"${lifetimes[*]}"))
middle=$((count/2))
if (( $count % 2 == 0 )); then
  median=$(((${sorted[$middle]} + ${sorted[$middle-1]}) / 2))
else
  median=${sorted[$middle]}
fi
echo "Median lifetime of a Pull Request is $(($median / 3600)) hours"

# Calculate and print the average
average=$((total / count))
echo "Average lifetime of a Pull Request is $(($average / 3600)) hours"