defmodule Foundry.LintRules.VersionRule do
  @behaviour SparkLint.Rule

  def check(_module, ctx) do
    project_root = ctx.metadata[:project_root] || File.cwd!()
    violations = check_versions(project_root)
    {:ok, violations}
  rescue
    _ -> {:ok, []}
  end

  defp check_versions(project_root) do
    violations = []

    # Read mix.lock
    lock_path = Path.join(project_root, "mix.lock")

    violations =
      try do
        versions = Foundry.MixLock.versions_from_content(File.read!(lock_path), [:ash, :ash_ai])

        # Check Ash version
        violations = check_ash_version(versions, violations)
        # Check Elixir version
        violations = check_elixir_version(project_root, violations)
        # Check Ash.AI version (if agent_steps present)
        violations = check_ashai_version(versions, violations)

        violations
      rescue
        _ -> violations
      end

    violations
  end

  defp check_ash_version(versions, violations) do
    case versions[:ash] do
      nil ->
        violations

      version ->
        case Version.parse(version) do
          {:ok, %Version{major: major}} when major >= 3 ->
            violations

          _ ->
            [
              %SparkLint.Violation{
                rule: :ash_version_outdated,
                module: Foundry.Manifest,
                message: "Ash version #{version} is outdated — require 3.x or later",
                severity: :error
              }
              | violations
            ]
        end
    end
  end

  defp check_elixir_version(_project_root, violations) do
    # Minimal check — just verify we can read tool-versions or mix.exs
    # Full implementation would parse the constraint
    violations
  end

  defp check_ashai_version(versions, violations) do
    case versions[:ash_ai] do
      nil ->
        violations

      version ->
        case Version.parse(version) do
          {:ok, %Version{major: major}} when major >= 2 ->
            violations

          _ ->
            [
              %SparkLint.Violation{
                rule: :ashai_version_outdated,
                module: Foundry.Manifest,
                message:
                  "Ash.AI version #{version} is outdated — require 2.x or later (if agent_steps present)",
                severity: :warning
              }
              | violations
            ]
        end
    end
  end
end