Module: Mermaid::GitgraphDiagramRenderer

Defined in:
lib/mermaid/gitgraph_diagram_renderer.rb

Overview

Module containing Mermaid rendering logic for Diagrams::GitgraphDiagram

Instance Method Summary collapse

Instance Method Details

#to_mermaid ⇒ Object 



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# File 'lib/mermaid/gitgraph_diagram_renderer.rb', line 9

def to_mermaid
  mermaid_string = +"gitGraph\n"
  processed_commits = Set.new # Track the current branch in Mermaid output (defaults to 'master')

  # Determine initial branch (default to 'main') and add checkout
  first_commit_id = commit_order.first
  # Default to 'main' if no commits or first commit doesn't specify branch
  # Default to 'main' if no commits exist or first commit doesn't specify branch
  initial_branch = (first_commit_id ? commits[first_commit_id]&.branch_name : nil) || 'master' # Default to 'master'
  mermaid_string << "  checkout #{initial_branch}\n"
  current_mermaid_branch = initial_branch

  commit_order.each do |commit_id|
    commit = commits[commit_id]
    next unless commit # Skip if commit data is missing

    # --- Determine Branch Context ---
    commit.branch_name

    # --- Handle Branch Creation & Checkout ---
    # Determine the branch this commit *should* be on based on its branch_name attribute
    target_branch_name = commit.branch_name

    # Check if a new branch *starts* at this commit's parent
    parent_commit_id = commit.parent_ids.first
    new_branch_starting_here = nil
    # Only consider branching if the target is NOT master and IS different from current
    if parent_commit_id && target_branch_name != 'master' && target_branch_name != current_mermaid_branch
      # Check if a branch object exists that starts at the parent and matches the target name
      new_branch_starting_here = branches.values.find do |b|
        b.start_commit_id == parent_commit_id && b.name == target_branch_name
      end
    end

    if new_branch_starting_here
      # Ensure we are on the parent branch before creating the new one
      parent_commit = commits[parent_commit_id]
      parent_branch_name = parent_commit&.branch_name
      if parent_branch_name && parent_branch_name != current_mermaid_branch
        mermaid_string << "  checkout #{parent_branch_name}\n"
        current_mermaid_branch = parent_branch_name
      end
      mermaid_string << "  branch #{target_branch_name}\n"
      # No checkout here, the next check handles it
    end

    # Now, handle checkout if needed for the current commit
    if target_branch_name != current_mermaid_branch
      # Always checkout if the branch differs from the last known Mermaid branch
      mermaid_string << "  checkout #{target_branch_name}\n"
      current_mermaid_branch = target_branch_name
    end

    # --- Handle Merge ---
    if commit.type == :MERGE && commit.parent_ids.length == 2 && !processed_commits.include?(commit_id)
      # Identify both parents
      parent1_id = commit.parent_ids[0]
      parent2_id = commit.parent_ids[1]
      parent1_commit = commits[parent1_id]
      parent2_commit = commits[parent2_id]

      # Find the parent commit whose branch is NOT the current branch
      source_commit = if parent1_commit&.branch_name != current_mermaid_branch
                        parent1_commit
                      elsif parent2_commit&.branch_name != current_mermaid_branch
                        parent2_commit
                      end
      source_branch_name = source_commit&.branch_name

      # Ensure source branch is valid and different from target
      if source_branch_name && source_branch_name != current_mermaid_branch
        mermaid_string << "  merge #{source_branch_name}"
        mermaid_string << " id: \"#{commit.id}\""
        mermaid_string << " tag: \"#{commit.tag}\"" if commit.tag
        mermaid_string << "\n"
        processed_commits.add(commit_id)
      else
        # If source branch can't be determined, generate a regular commit as fallback
        warn "Could not determine source branch for merge commit #{commit_id}. Generating standard commit."
        generate_commit_line(mermaid_string, commit, processed_commits) unless processed_commits.include?(commit_id)
      end

    # --- Handle Standard Commit ---
    elsif !processed_commits.include?(commit_id)
      generate_commit_line(mermaid_string, commit, processed_commits)
    end
  end

  mermaid_string.strip
end