@spec adjacency_list(%{required(String.t()) => NPM.Lockfile.entry()}) :: %{
  required(String.t()) => [String.t()]
}

Build an adjacency list from the lockfile.

Returns %{name => [dep_name, ...]}.

@spec cycles(%{required(String.t()) => [String.t()]}) :: [[String.t()]]

Detect circular dependencies. Returns list of cycle paths.

Uses Erlang's :digraph_utils for reliable cycle detection.

@spec fan_in(%{required(String.t()) => [String.t()]}) :: %{
  required(String.t()) => non_neg_integer()
}

Compute fan-in (number of dependents) for each package.

@spec fan_out(%{required(String.t()) => [String.t()]}) :: %{
  required(String.t()) => non_neg_integer()
}

Compute fan-out (number of dependencies) for each package.

@spec impact(%{required(String.t()) => [String.t()]}, String.t()) :: non_neg_integer()

Compute impact score — how many packages transitively depend on a package.

@spec leaves(%{required(String.t()) => [String.t()]}) :: [String.t()]

Find leaf packages (no dependencies).

@spec max_depth(%{required(String.t()) => [String.t()]}, String.t()) ::
  non_neg_integer()

Compute the maximum dependency depth from a package.

@spec reverse(%{required(String.t()) => [String.t()]}) :: %{
  required(String.t()) => [String.t()]
}

Reverse the graph so all edges point from dependencies to dependents.

@spec roots(%{required(String.t()) => [String.t()]}) :: [String.t()]

Find root packages (not depended on by any other package).

@spec shortest_path(%{required(String.t()) => [String.t()]}, String.t(), String.t()) ::
  [String.t()] | nil

Find the shortest path between two packages.

@spec transitive_deps(%{required(String.t()) => [String.t()]}, String.t()) ::
  MapSet.t(String.t())

Compute the transitive closure — all reachable packages from a root.