#!/bin/bash

# get_contributors.sh
# A script to collect all contributors to a Git repository, quantify their contributions,
# combine stats from the same person using different names/emails, and fetch GitHub profile information.
#
# Created by Joshua Kolden (https://github.com/mrjoshuak)
#
# Usage: ./get_contributors.sh [path_to_repo] [github_repo_owner/repo_name] [mapping_file]
#
# The optional mapping_file is a text file with lines in the format:
# name_or_email_pattern|normalized_key
#
# Example mapping file:
# # Lines starting with # are comments
# John|johndoe
# john.doe@example.com|johndoe
# Jane Smith|janesmith

# Set the repository path and other parameters
REPO_PATH=${1:-.}
GITHUB_REPO=${2:-""}
MAPPING_FILE=${3:-""}

# Check if the path exists and is a git repository
if [ ! -d "$REPO_PATH/.git" ]; then
	echo "Error: $REPO_PATH is not a git repository"
	exit 1
fi

# Change to the repository directory
cd "$REPO_PATH" || exit 1

echo "Analyzing contributors for repository: $(basename "$PWD")"
echo "------------------------------------------------------"

# Check for GitHub API credentials
if [ -n "$GITHUB_TOKEN" ]; then
	echo "GitHub API token found in environment"
	GITHUB_AUTH="Authorization: token $GITHUB_TOKEN"
elif [ -n "$GITHUB_API_TOKEN" ]; then
	echo "GitHub API token found in environment"
	GITHUB_AUTH="Authorization: token $GITHUB_API_TOKEN"
else
	echo "No GitHub API token found in environment. Will use unauthenticated API calls (rate limited)."
	GITHUB_AUTH=""
fi

# If no GitHub repo was provided, try to guess it from the remote URL
if [ -z "$GITHUB_REPO" ]; then
	REMOTE_URL=$(git config --get remote.origin.url)
	if [[ "$REMOTE_URL" == *"github.com"* ]]; then
		# Extract owner/repo from the URL
		GITHUB_REPO=$(echo "$REMOTE_URL" | sed -E 's|.*github\.com[:/]([^/]+/[^/]+)(\.git)?|\1|')
		echo "Detected GitHub repository: $GITHUB_REPO"
	else
		echo "No GitHub repository specified and couldn't detect one from remotes."
		echo "GitHub profile information will not be available."
	fi
fi

# Get all contributors with their commit counts, lines added, and lines deleted
echo "Collecting contribution data..."

# Create temporary files
TEMP_FILE=$(mktemp)
NORM_FILE=$(mktemp)
MANUAL_MAP=$(mktemp)
GITHUB_INFO=$(mktemp)
GITHUB_USERNAME_MAP=$(mktemp)

# Create a default manual mapping file if no mapping file is provided
if [ -z "$MAPPING_FILE" ] || [ ! -f "$MAPPING_FILE" ]; then
	echo "# No custom mapping file provided. Using default empty mapping." >"$MANUAL_MAP"
else
	echo "Using mapping file: $MAPPING_FILE"
	cp "$MAPPING_FILE" "$MANUAL_MAP"
fi

# Create a default GitHub username mapping file
cat >"$GITHUB_USERNAME_MAP" <<EOF
# Format: name_or_email_pattern|github_username
# This file maps contributors to their GitHub usernames
EOF

# Get all authors and their emails
git log --format='%an|%ae' | sort | uniq >/tmp/contributors.txt

# Process each contributor and normalize names
while IFS='|' read -r name email; do
	# Check if this contributor matches any manual mapping
	manual_key=""
	while IFS='|' read -r pattern key; do
		# Skip comments
		if [[ "$pattern" == \#* ]]; then
			continue
		fi

		# Check if pattern matches name or email
		if [[ "$name" == *"$pattern"* || "$email" == *"$pattern"* ]]; then
			manual_key="$key"
			break
		fi
	done <"$MANUAL_MAP"

	# If no manual mapping, create a normalized key from the name
	if [[ -z "$manual_key" ]]; then
		# Create a simple normalized name (lowercase, alphanumeric only)
		manual_key=$(echo "$name" | tr '[:upper:]' '[:lower:]' | tr -cd 'a-z0-9')
	fi

	# Get commit count
	commits=$(git log --author="$name" --pretty=oneline | wc -l | tr -d ' ')

	# Get lines added and deleted
	stats=$(git log --author="$name" --pretty=tformat: --numstat | awk '{ add += $1; del += $2 } END { printf "%d %d", add, del }')
	added=$(echo "$stats" | cut -d' ' -f1)
	deleted=$(echo "$stats" | cut -d' ' -f2)

	# Calculate a "contribution score" (commits + added + deleted)
	score=$((commits + added + deleted))

	# Output to the temporary file with normalized name for later combining
	echo "$manual_key|$score|$commits|$added|$deleted|$name|$email" >>"$NORM_FILE"

done </tmp/contributors.txt

# Combine entries with the same normalized key
cat "$NORM_FILE" | sort -t'|' -k1,1 | awk -F'|' '
BEGIN { OFS="|" }
{
	if ($1 == prev_key) {
		# Add stats
		total_score += $2
		total_commits += $3
		total_added += $4
		total_deleted += $5

		# Keep the longer name
		if (length($6) > length(prev_name)) {
			prev_name = $6
			prev_email = $7
		}
	} else {
		# Output previous combined entry
		if (prev_key != "") {
			print total_score, total_commits, total_added, total_deleted, prev_name, prev_email
		}

		# Start new entry
		prev_key = $1
		prev_name = $6
		prev_email = $7
		total_score = $2
		total_commits = $3
		total_added = $4
		total_deleted = $5
	}
}
END {
	# Output the last entry
	if (prev_key != "") {
		print total_score, total_commits, total_added, total_deleted, prev_name, prev_email
	}
}' >"$TEMP_FILE"

# Function to extract GitHub username from email
extract_github_username() {
	local email="$1"
	local username=""

	# Check if it's a GitHub noreply email
	if [[ "$email" == *"@users.noreply.github.com"* ]]; then
		# Extract the username or ID
		username=$(echo "$email" | sed -E 's/^([0-9]+\+)?([^@]+)@users\.noreply\.github\.com$/\2/')
	fi

	echo "$username"
}

# Function to get GitHub info for a user
get_github_info() {
	local email="$1"
	local name="$2"
	local github_username=""
	local full_name=""
	local profile_url=""

	# Check if this user has a manual GitHub username mapping
	while IFS='|' read -r pattern username; do
		# Skip comments
		if [[ "$pattern" == \#* ]]; then
			continue
		fi

		# Check if pattern matches name or email
		if [[ "$name" == *"$pattern"* || "$email" == *"$pattern"* ]]; then
			github_username="$username"
			break
		fi
	done <"$GITHUB_USERNAME_MAP"

	# If no manual mapping, try to extract from email
	if [ -z "$github_username" ]; then
		github_username=$(extract_github_username "$email")
	fi

	# If we have a GitHub repo and username or email, try to get more info
	if [ -n "$GITHUB_REPO" ]; then
		# Try to find the contributor in the GitHub repo contributors list
		if [ -z "$github_username" ]; then
			# Search by email
			if [ -n "$GITHUB_AUTH" ]; then
				# Use authenticated API call
				response=$(curl -s -H "$GITHUB_AUTH" "https://api.github.com/search/users?q=$email+in:email")
				if [ "$(echo "$response" | grep -c "total_count.*[1-9]")" -gt 0 ]; then
					github_username=$(echo "$response" | grep -o '"login": *"[^"]*"' | head -1 | sed 's/"login": *"\([^"]*\)"/\1/')
				fi
			fi

			# If still no username, try to search by name
			if [ -z "$github_username" ]; then
				if [ -n "$GITHUB_AUTH" ]; then
					response=$(curl -s -H "$GITHUB_AUTH" "https://api.github.com/search/users?q=$name+in:name")
					if [ "$(echo "$response" | grep -c "total_count.*[1-9]")" -gt 0 ]; then
						github_username=$(echo "$response" | grep -o '"login": *"[^"]*"' | head -1 | sed 's/"login": *"\([^"]*\)"/\1/')
					fi
				fi
			fi
		fi

		# If we found a GitHub username, get their profile info
		if [ -n "$github_username" ]; then
			profile_url="https://github.com/$github_username"

			# Get full name from GitHub profile if we have auth
			if [ -n "$GITHUB_AUTH" ]; then
				user_info=$(curl -s -H "$GITHUB_AUTH" "https://api.github.com/users/$github_username")
				full_name=$(echo "$user_info" | grep -o '"name": *"[^"]*"' | sed 's/"name": *"\([^"]*\)"/\1/')

				# If no full name, use the username
				if [ -z "$full_name" ] || [ "$full_name" = "null" ]; then
					full_name="$github_username"
				fi
			else
				full_name="$github_username"
			fi
		fi
	fi

	# If we couldn't get GitHub info, use the name from git
	if [ -z "$full_name" ]; then
		full_name="$name"
	fi

	# Return the info
	echo "$full_name|$github_username|$profile_url"
}

# Get GitHub info for each contributor
echo "Fetching GitHub profile information..."
if [ -n "$GITHUB_REPO" ]; then
	sort -t'|' -k1,1nr "$TEMP_FILE" | while IFS='|' read -r score commits added deleted name email; do
		# Skip entries with zero score
		if [[ $score -eq 0 ]]; then
			continue
		fi

		# Get GitHub info
		github_info=$(get_github_info "$email" "$name")
		IFS='|' read -r full_name github_username profile_url <<<"$github_info"

		# Output to GitHub info file
		echo "$score|$commits|$added|$deleted|$name|$email|$full_name|$github_username|$profile_url" >>"$GITHUB_INFO"
	done

	# Display the results with GitHub info
	echo "Name                            GitHub Username               Profile                         Commits    Added     Deleted   Score"
	echo "--------------------------------------------------------------------------------------------------------------"
	cat "$GITHUB_INFO" | while IFS='|' read -r score commits added deleted name email full_name github_username profile_url; do
		# Use full name if available, otherwise use git name
		display_name="$full_name"
		if [ -z "$display_name" ]; then
			display_name="$name"
		fi

		# Use username if available, otherwise blank
		display_username="$github_username"
		if [ -z "$display_username" ]; then
			display_username="-"
		fi

		# Use profile URL if available, otherwise blank
		display_url="$profile_url"
		if [ -z "$display_url" ]; then
			display_url="-"
		fi

		printf "%-30s %-30s %-30s %-10s %-10s %-10s %-10s\n" "$display_name" "$display_username" "$display_url" "$commits" "$added" "$deleted" "$score"
	done
else
	# Display the results without GitHub info
	echo "Name                            Email                           Commits    Added     Deleted   Score"
	echo "--------------------------------------------------------------------------------------------"
	sort -t'|' -k1,1nr "$TEMP_FILE" | while IFS='|' read -r score commits added deleted name email; do
		# Skip entries with zero score
		if [[ $score -eq 0 ]]; then
			continue
		fi
		printf "%-30s %-30s %-10s %-10s %-10s %-10s\n" "$name" "$email" "$commits" "$added" "$deleted" "$score"
	done
fi

# Clean up temporary files
rm -f /tmp/contributors.txt "$TEMP_FILE" "$NORM_FILE" "$MANUAL_MAP" "$GITHUB_INFO" "$GITHUB_USERNAME_MAP"

echo "------------------------------------------------------"
echo "Note: 'Score' is a simple metric calculated as (commits + lines added + lines deleted)"
echo "This is a basic quantification and doesn't account for the complexity or impact of contributions."
echo "Contributors with multiple email addresses have been combined where possible."