# SPDX-License-Identifier: Apache-2.0
# SPDX-FileCopyrightText: 2025 DBVisor
if Code.ensure_loaded?(:yamerl) do
  defmodule Mix.Tasks.Sql.Gen.Test do
    use Mix.Task
    import Mix.Generator
    @moduledoc since: "0.2.0"

    @shortdoc "Generates test from the BNF rules"
    def run([base]) do
      create_file("test/conformance/e_test.exs", test_template([mod: SQL.Conformance.ETest, dir: Path.join(base, "E")]), force: true)
      create_file("test/conformance/f_test.exs", test_template([mod: SQL.Conformance.FTest, dir: Path.join(base, "F")]), force: true)
      create_file("test/conformance/s_test.exs", test_template([mod: SQL.Conformance.STest, dir: Path.join(base, "S")]), force: true)
      create_file("test/conformance/t_test.exs", test_template([mod: SQL.Conformance.TTest, dir: Path.join(base, "T")]), force: true)
    end

    def generate_test(dir) do
      for path <- File.ls!(dir), path =~ ".tests.yml", [{~c"feature", feature}, {~c"id", id}, {~c"sql", sql}] <- :yamerl.decode_file(to_charlist(Path.join(dir, path))) do
        statements = if is_list(hd(sql)), do: sql, else: [sql]
        statements = Enum.map(statements, &String.replace(to_string(&1), ~r{(VARING)}, "VARYING"))
        {"#{feature} #{id}", Enum.map(statements, &{trim(&1), &1})}
      end
    end

    def trim(value) do
      value
      |> String.replace(~r{\(\s+\b}, &String.replace(&1, " ", ""))
      |> String.replace(~r{\(\s+'}, &String.replace(&1, " ", ""))
      |> String.replace(~r{\(\s+"}, &String.replace(&1, " ", ""))
      |> String.replace(~r{\(\s+\*}, &String.replace(&1, " ", ""))
      |> String.replace(~r{\b\s+\,}, &String.replace(&1, " ", ""))
      |> String.replace(~r{\)\s+\,}, &String.replace(&1, " ", ""))
      |> String.replace(~r{\'\s+\,}, &String.replace(&1, " ", ""))
      |> String.replace(~r{\b\s+\)}, &String.replace(&1, " ", ""))
      |> String.replace(~r{'\s+\)}, &String.replace(&1, " ", ""))
      |> String.replace(~r{\*\s+\)}, &String.replace(&1, " ", ""))
      |> String.replace(~r{\)\s+\)}, &String.replace(&1, " ", ""))
      |> String.replace(~r{(A)\s\+\d}, &Enum.join(Regex.split(~r{\d}, &1, include_captures: true, trim: true), " "))
      |> String.replace(~r{\W(SELECT|REFERENCES|INSERT|UPDATE|IN|MYTEMP)\(}, &Enum.join(Regex.split(~r{\(}, &1, include_captures: true, trim: true), " "))
      |> String.replace(~r{^(SELECT)\(}, &Enum.join(Regex.split(~r{\(}, &1, include_captures: true, trim: true), " "))
      |> String.replace(~r{\s+\.\s+}, &String.replace(&1, " ", ""))
      |> String.replace(~r{\d\s(\+|\-)\d}, &Enum.join(Enum.map(Regex.split(~r{\+|\-}, &1, include_captures: true, trim: true), fn x -> String.trim(x) end), " "))
      |> String.trim()
  end

    embed_template(:test, """
    # SPDX-License-Identifier: Apache-2.0
    # SPDX-FileCopyrightText: 2025 DBVisor

    defmodule <%= inspect @mod %>.Adapter do
      use SQL.Token

      def token_to_string(value, mod \\\\ __MODULE__)
      def token_to_string(value, _mod) when is_atom(value), do: String.upcase(Atom.to_string(value))
      def token_to_string(token, mod), do: SQL.Adapters.ANSI.token_to_string(token, mod)

      def to_iodata(value, _context, _indent) when is_atom(value) do
        String.upcase(Atom.to_string(value))
      end
      def to_iodata(token, context, indent), do: SQL.Adapters.ANSI.to_iodata(token, context, indent)
      def to_iodata(tokens, context, indent, acc), do: SQL.Adapters.ANSI.to_iodata(tokens, context, indent, acc)
    end
    defmodule <%= inspect @mod %> do
      use ExUnit.Case, async: true
      use SQL, adapter: <%= inspect @mod %>.Adapter

      <%= for {name, statements} <- generate_test(@dir) do %>
      test <%= inspect name %> do
        <%= for {left, right} <- statements do %>
        assert ~s{<%= left %>} == to_string(~SQL[<%= right %>])
        <% end %>
      end
      <% end %>
    end
    """)
  end
end