# Copyright (c) 2020 James Laver, mess Contributors
#
# This Source Code Form is subject to the terms of the Mozilla Public
# License, v. 2.0. If a copy of the MPL was not distributed with this
# file, You can obtain one at http://mozilla.org/MPL/2.0/.
if not Code.ensure_loaded?(Mess) do
  defmodule Mess do
    @newline ~r/(?:\r\n|[\r\n])/
    @parser ~r/^(?<indent>\s*)((?<package>[a-z_][a-z0-9_]+)\s*=\s*"(?<value>[^"]+)")?(?<post>.*)/
    @git_branch ~r/(?<repo>[^#]+)(#(?<branch>.+))?/
    @ext_forks_path System.get_env("FORKS_PATH", "extensions/")

    defp sources(true), do: [path: "deps.path", git: "deps.git", hex: "deps.hex"]
    defp sources(_), do: [git: "deps.git", hex: "deps.hex"]

    defp opts(opts) do
      opts =
        opts
        |> Keyword.put_new_lazy(:use_local_forks?, fn ->
          System.get_env("WITH_FORKS", "1") == "1"
        end)

      # NOTE: we check MIX_ENV instead of `Mix.env` because it incorrectly returns :prod when doing deps.get
      opts =
        opts
        |> Keyword.put_new_lazy(:use_umbrella?, fn ->
          System.get_env("MIX_ENV", "dev") == "dev" and opts[:use_local_forks?] and
            System.get_env("AS_UMBRELLA") == "1"
        end)

      opts
      |> Keyword.put_new_lazy(:umbrella_path, fn ->
        if opts[:use_umbrella?], do: @ext_forks_path, else: nil
      end)

      # |> IO.inspect(label: "opts for #{File.cwd!}")
    end

    def deps(sources \\ nil, extra_deps, opts \\ []) do
      opts = opts(opts)

      (sources || sources(opts[:use_local_forks?]))
      # |> IO.inspect()
      |> enum_deps()
      |> deps_packages(extra_deps, opts)
    end

    defp enum_deps({k, v}) do
      read(v, k)
    end

    defp enum_deps(sublist) when is_list(sublist) do
      sublist
      |> Enum.flat_map(&enum_deps/1)
    end

    defp deps_packages(packages, extra_deps, opts),
      do:
        (Enum.flat_map(packages, &dep_spec(&1, opts)) ++ extra_deps)
        |> deps_uniq(opts)
        |> maybe_filter_umbrella(opts)

    defp deps_uniq(packages, opts),
      do:
        packages
        # |> IO.inspect(label: "non-unique")
        |> maybe_filter_invalid_paths(opts)
        |> Enum.uniq_by(&elem(&1, 0))

    defp maybe_filter_invalid_paths(deps, _opts) do
      Enum.reject(deps, fn dep ->
        dep_opts = elem(dep, 1)
        is_list(dep_opts) and dep_opts[:path] && not File.exists?("#{dep_opts[:path]}/mix.exs")
      end)
    end

    defp maybe_filter_umbrella(deps, opts) do
      cond do
        opts[:umbrella_root?] ->
          Enum.reject(deps, fn dep ->
            dep_opts = elem(dep, 1)
            is_list(dep_opts) and dep_opts[:from_umbrella]
          end)

        # |> IO.inspect(label: "umbrella_root")

        opts[:umbrella_only] ->
          Enum.filter(deps, fn dep ->
            dep_opts = elem(dep, 1)
            is_list(dep_opts) and dep_opts[:from_umbrella]
          end)

        # |> IO.inspect(label: "umbrella_only")

        opts[:use_umbrella?] ->
          umbrella_deps = read_umbrella(opts)
          # |> IO.inspect(label: "umbrella_deps for #{File.cwd!}")

          deps
          |> Enum.map(fn dep ->
            name = elem(dep, 0)

            case umbrella_deps[name] do
              nil ->
                dep

              dep_opts ->
                if dep_opts[:from_umbrella] do
                  {name, in_umbrella: true, override: true}
                else
                  {
                    name,
                    dep_opts
                    # |> Keyword.put(:path, "../../#{dep_opts[:path]}")
                  }
                end
            end
          end)

        # |> IO.inspect(label: "in_umbrella")
        true ->
          deps
      end
    end

    defp read_umbrella(opts) do
      path = "../../config/deps.path"

      if opts[:use_local_forks?] and File.exists?(path) do
        [path, "../../config/deps.flavour.path"]
        |> Enum.flat_map(&read(&1, :path))
        |> Enum.flat_map(&dep_spec(&1, opts))
      else
        # IO.puts("did not load #{path}")
        []
      end
    end

    defp read(path, kind) when is_binary(path), do: have_read(File.read(path), path, kind)

    defp have_read({:error, :enoent}, _path, _kind) do
      # IO.puts("Could not find #{path} in #{File.cwd!()}")
      []
    end

    defp have_read({:ok, file}, _, kind),
      do: Enum.map(String.split(file, @newline), &read_line(&1, kind))

    defp read_line(line, kind),
      do: Map.put(Regex.named_captures(@parser, line), :kind, kind)

    defp dep_spec(%{"package" => ""}, _opts), do: []

    defp dep_spec(%{"package" => p, "value" => v, :kind => :hex}, _opts),
      do: pkg(p, v, override: true)

    defp dep_spec(%{"package" => p, "value" => v, :kind => :path}, opts) do
      umbrella_path = opts[:umbrella_path]

      if umbrella_path && String.starts_with?(v, umbrella_path) do
        if opts[:umbrella_root?] do
          pkg(p, from_umbrella: true, override: true, path: "../../#{v}")
          # |> IO.inspect(label: "from_umbrella: #{p}")
        else
          pkg(p, in_umbrella: true, override: true)
          # |> IO.inspect(label: "in_umbrella: #{p}")
        end
      else
        pkg(p, path: v, override: true)
      end
    end

    defp dep_spec(%{"package" => p, "value" => v, :kind => :git}, _opts), do: git(v, p)

    defp git(line, p) when is_binary(line),
      do: git(Regex.named_captures(@git_branch, line), p)

    defp git(%{"branch" => "", "repo" => r}, p),
      do: pkg(p, git: r, override: true)

    defp git(%{"branch" => b, "repo" => r}, p),
      do: pkg(p, git: r, branch: b, override: true)

    defp pkg(name, opts), do: [{String.to_atom(name), opts}]
    defp pkg(name, version, opts), do: [{String.to_atom(name), version, opts}]
  end
end