#!/bin/bash

# Function to escape special characters for Mermaid
escape_for_mermaid() {
    echo "$1" | sed 's/[^a-zA-Z0-9]/_/g'
}

# Output file
output_file="branches_diagram.mmd"

# Start the Mermaid diagram
{
echo "%%{init: { 'theme': 'base' } }%%"
echo "gitGraph"

# Set master as the main branch
main_branch="master"

# Start with the main branch
echo "    commit id: \"Initial commit\""
echo "    branch $main_branch"
echo "    checkout $main_branch"

# Keep track of declared branches
declare -A declared_branches
declared_branches[$main_branch]=1

# Function to find the base branch
find_base_branch() {
    local branch=$1
    local base=$(git show-branch -a 2>/dev/null | grep '\*' | grep -v "$branch" | head -n1 | sed 's/.*\[\(.*\)\].*/\1/' | sed 's/[\^~].*//')
    if [[ -z "$base" ]]; then
        echo "$main_branch"
    else
        echo "$base"
    fi
}

# Function to declare a branch if not already declared
declare_branch() {
    local branch=$1
    if [[ -z "${declared_branches[$branch]}" ]]; then
        echo "    branch $(escape_for_mermaid "$branch")"
        declared_branches[$branch]=1
    fi
}

# Process each branch
for branch in $(git for-each-ref --sort=committerdate --format='%(refname:short)' refs/heads/); do
    base_branch=$(find_base_branch "$branch")

    declare_branch "$branch"

    echo "    checkout $(escape_for_mermaid "$branch")"
    echo "    commit id: \"$(git log -1 --pretty=format:%s "$branch")\""

    if [ "$branch" != "$main_branch" ]; then
        echo "    checkout $(escape_for_mermaid "$base_branch")"
        echo "    merge $(escape_for_mermaid "$branch")"
    fi
done
} > $output_file

echo "Mermaid diagram saved to $output_file"