defmodule PropCheck.StateM.Reporter do
  @moduledoc false

  alias PropCheck.StateM

  @type mod_alias :: module() | {module(), as :: module()}
  @type option :: {:return_values, boolean}
                | {:last_state, boolean}
                | {:pre_cmd_state, boolean}
                | {:post_cmd_state, boolean}
                | {:cmd_args, boolean}
                | {:inspect_opts, keyword}
                | {:alias, mod_alias | [mod_alias]}

  @type options :: [option]

  @spec print_report({StateM.history, StateM.dynamic_state, StateM.result},
    StateM.command_list, options) :: :ok
  def print_report({history, state, result}, commands, opts \\ []),
    do: pretty_report(result, history, state, commands, opts)

  defp pretty_report(_result, seq_history, par_history, cmds, opts) when is_tuple(cmds) do
    title = "Concurrency Failure, we don't show the state :-/"
    history = [{:sequential, seq_history}, {:parallel, par_history}]
    print_pretty_report(title, :parallel, history, :no_state, cmds, opts)
  end
  defp pretty_report(:ok, history, state, commands, opts),
    do: print_pretty_report(
          "All commands were successful and all postconditions were true.",
          :all, history, state, commands, opts
        )

  defp pretty_report(:initialization_error, history, state, commands, opts),
    do: print_pretty_report("Error while evaluating initial state.", :none,
      history, state, commands, opts)

  defp pretty_report({:precondition, false}, history, state, commands, opts) do
    failing_cmd_idx = {:fail_at, length(history)}
    print_pretty_report("Precondition failed.", failing_cmd_idx,
      history, state, commands, opts)
  end

  defp pretty_report({:precondition, exp = {:exception, _, _, _}}, history,
    state, commands, opts) do
    failing_cmd_idx = {:fail_at, length(history)}
    title =  "Precondition crashed:\n" <> inspectx(exp, opts)
    print_pretty_report(title, failing_cmd_idx, history, state, commands, opts)
  end

  defp pretty_report({:postcondition, false}, history, state, commands, opts) do
    failing_cmd_idx = {:fail_at, length(history) - 1}
    print_pretty_report("Postcondition failed.", failing_cmd_idx,
      history, state, commands, opts)
  end

  defp pretty_report({:postcondition, exp = {:exception, _, _, _}}, history,
    state, commands, opts) do
    failing_cmd_idx = {:fail_at, length(history) - 1}
    title =  "Postcondition crashed:\n#{inspectx(exp, opts)}"
    print_pretty_report(title, failing_cmd_idx, history, state, commands, opts)
  end

  defp pretty_report(exp = {:exception, _, _, _}, history, state, commands, opts) do
    failing_cmd_idx = {:fail_at, length(history)}
    history = history ++ [{state, exp}]
    print_pretty_report("Command crashed.", failing_cmd_idx, history, state,
      commands, opts)
  end

  @header String.duplicate("=", 80)
  defp print_pretty_report(title, cmds_to_print, history, state, [{:init, _} | commands], opts),
    do: print_pretty_report(title, cmds_to_print, history, state, commands, opts)
  defp print_pretty_report(title, cmds_to_print, history, state, commands, opts) do
    main = main_section(cmds_to_print, history, state, commands, opts)
    IO.puts """

    #{@header}
    #{title}

    #{main}
    """
  end

  defp main_section(cmds_to_print, history, state, commands, opts)
  defp main_section(:none, _history, _state, _commands, _opts),
    do: ""
  defp main_section(:all, history, state, commands, opts) do
    history_commands = zip_cmds_history(commands, history)
    last_state = last_state_section(state, opts)
    cmds = history_commands |> print_command_lines(false, opts) |> Enum.join("\n")

    """
    Commands:
    #{cmds}
    #{last_state}
    """
  end
  defp main_section({:fail_at, cmd_idx}, history, state, commands, opts) do
    history_commands = zip_cmds_history(commands, history)
    last_state = last_state_section(state, opts)

    # commands before the failing one
    priori_cmds =
      history_commands
      |> Enum.take(cmd_idx)
      |> print_command_lines(false, opts)

    # failing command
    failing_cmd =
      history_commands
      |> Enum.at(cmd_idx)
      |> print_command_line(true, opts)

    cmds = Enum.join priori_cmds ++ [failing_cmd], "\n"
    """
    Commands:
    #{cmds}
    #{last_state}
    """
  end
  defp main_section(:parallel, history, _state, cmds, opts) do

    # require Logger
    # Logger.info "Main Section (parallel): history = #{inspect history, pretty: true}"
    # Logger.info "Main Section (parallel): state = #{inspect state, pretty: true}"
    # Logger.info "Main Section (parallel): cmds = #{inspect cmds, pretty: true}"

    {seq_cmds, [p1_cmds, p2_cmds]} = cmds
    seq_history = Keyword.fetch!(history, :sequential)

    [p1_history, p2_history] = case Keyword.fetch(history, :parallel) do
      {:ok, [h1, h2]} ->
        remove_cmd = fn {_cmd, return} -> {nil, return} end
        [Enum.map(h1, remove_cmd), Enum.map(h2, remove_cmd)]
      :error -> [[], []]
    end

    seq_commands = zip_sequential_cmds_history(seq_cmds, seq_history)
    |> print_command_lines(false, opts)
    |> Enum.join("")

    par_opts = Keyword.merge([post_cmd_state: false], opts)
    p1_states = zip_parallel_cmds_history(p1_cmds, p1_history) |> print_command_lines(false, par_opts)|> Enum.join("")
    p2_states = zip_parallel_cmds_history(p2_cmds, p2_history) |> print_command_lines(false, par_opts)|> Enum.join("")

    # par_commands_1 = "#{inspect p1_history, pretty: true}"
    # par_commands_2 = "#{inspect p2_history, pretty: true}"
    """
    Sequential commands:
    #{seq_commands}

    Process 1:
    #{p1_states}

    Process 2:
    #{p2_states}
    """
  end

  defp zip_parallel_cmds_history(cmds, history) do
    Enum.zip(cmds, history)
    |> Enum.map(fn {cmd, {_cmd_hist, ret_value}} -> {cmd, {ret_value, nil, nil}} end)
  end

  defp zip_sequential_cmds_history(cmds, history) do
    Enum.zip(cmds, history)
    |> Enum.map(fn {cmd, {post_state, ret_value}} -> {cmd, {ret_value, nil, {:just, post_state}}} end)
  end

  defp last_state_section(state, opts) do
    case Keyword.get(opts, :last_state, true) do
      true ->
        """

        Last state:
        #{inspectx state, opts}
        """
      false -> ""
    end
  end

  defp zip_cmds_history(commands, history) do
    zipper = fn cmd, acc ->
      case acc do
        {[], zipped} ->
          {[], [{cmd, nil} | zipped]}

        {[{pre_state, return_val}], zipped} ->
          post_state = nil
          {[], [{cmd, {return_val, pre_state, post_state}} | zipped]}

        {[{pre_state, return_val}, h = {post_state, _} | history], zipped} ->
          {[h|history], [{cmd, {return_val, pre_state, {:just, post_state}}} | zipped]}
      end
    end
    Enum.reduce(commands, {history, []}, zipper)
    |> elem(1)
    |> Enum.reverse
  end

  defp print_command_lines(hist_cmds, failing?, opts) do
    Enum.map(hist_cmds, &print_command_line(&1, failing?, opts))
  end
  defp print_command_line({cmd, history}, failing?, opts) do
    has_history? = match?({_return_val, _pre_state, _post_state}, history)
    print_return_val? = has_history? and Keyword.get(opts, :return_values, true)
    print_pre_state? = has_history? and Keyword.get(opts, :pre_cmd_state, false)
    print_post_state? = has_history? and Keyword.get(opts, :post_cmd_state, true)

    [
      if(print_pre_state?, do: print_pre_state(history, opts), else: ""),
      print_command(cmd, failing?, opts),
      if(print_return_val?, do: print_return_value(history, opts), else: ""),
      if(print_post_state?, do: print_post_state(history, opts), else: ""),
    ]
    |> to_string
  end

  @doc false
  def pretty_print_counter_example_cmd({:init, _}), do: ""
  def pretty_print_counter_example_cmd(cmd) do
    pretty_cmd_name(cmd, [syntax_colors: []]) <> "\n"
  end

  def pretty_print_counter_example_parallel({seq, [par1, par2]}) do
    (IO.ANSI.format([:reset, "Sequential Start: \n"]) |> to_string()) <>
    (print_parallel_commands(seq, false, [syntax_colors: []])  |> Enum.join("")) <> "\n" <>
    "Parallel Process 1: \n" <>
    (print_parallel_commands(par1, false, [syntax_colors: []]) |> Enum.join("")) <> "\n" <>
    "Parallel Process 2: \n" <>
    (print_parallel_commands(par2, false, [syntax_colors: []]) |> Enum.join("")) <> "\n"
  end
  defp print_parallel_commands(cmds, failing?, opts) do
    history = [] # there is no history in parallel test cases
    cmds
    |> zip_cmds_history(history)
    |> print_command_lines(failing?, opts)
  end

  @cmd_indent_level 3
  @comment_indent_level 10
  defp print_command(cmd, failing?, opts)
  defp print_command(cmd, false, opts),
    do: indent(pretty_cmd_name(cmd, opts), @cmd_indent_level, false) <> "\n"
  defp print_command(cmd, true, opts) do
    cmt =
      [:red, "#! ", :reset]
      |> IO.ANSI.format() |> to_string
    cmd_str =
      [:red, pretty_cmd_name(cmd, opts), :reset]
      |> IO.ANSI.format() |> to_string
    indent(cmd_str, @cmd_indent_level, cmt) <> "\n"
  end

  defp print_return_value({return_val, _, _}, opts) do
    comment("->", return_val, opts)
  end

  defp print_pre_state({_, pre_state, _}, opts) do
    comment("Pre state:", pre_state, opts)
  end

  defp print_post_state({_, _, nil}, _opts), do: ""
  defp print_post_state({_, _, {:just, post_state}}, opts) do
    # "\n" <> comment("Post state:", post_state, opts)
    comment("Post state:", post_state, opts)
  end

  defp comment(title, val, opts) do
    str = inspectx(val, opts)
    indent("#{title} #{str}", @comment_indent_level, true) <> "\n"
  end

  defp indent(str, level, commented?)
  defp indent(str, level, false) do
    String.duplicate(" ", level)
    |> do_indent(str)
  end
  defp indent(str, level, true) when level > 2 do
    (String.duplicate(" ", level - 2) <> "# ")
    |> do_indent(str)
  end
  defp indent(str, _level, true),
    do: do_indent("# ", str)

  defp indent(str, level, cmt) when is_binary(cmt) do
    length = String.length(cmt)

    if level > length do
      (String.duplicate(" ", level - length) <> cmt)
      |> do_indent(str)
    else
      do_indent(cmt, str)
    end
  end

  defp do_indent(indent, str) do
    str
    |> String.split("\n")
    |> Enum.map(& "#{indent}#{&1}")
    |> Enum.join("\n")
  end

  def pretty_cmds_name(cmds, opts) do
    Enum.map(cmds, &pretty_cmd_name(&1, opts))
  end

  def pretty_cmd_name([tuple], opts), do: pretty_cmd_name(tuple, opts)
  def pretty_cmd_name({:init, data}, _opts), do: "init call -> #{inspect data, pretty: true}"
  def pretty_cmd_name({:set, {:var, n}, {:call, mod, fun, args}}, opts) do
    aliases = Keyword.get(opts, :alias, [mod])
    mod = alias_module(mod, aliases)
    args =
      args
      |> Enum.with_index()
      |> Enum.map(fn
        {{:var, m}, _} -> symb_var(m)
        {arg, i} -> case Keyword.get(opts, :cmd_args, true) do
               true -> inspectx(arg, opts)
               false -> "arg#{n}_#{i+1}"
             end
      end)
      |> Enum.join(", ")
    "#{symb_var(n)} = #{inspect mod}.#{fun}(#{args})"
  end

  defp symb_var(x) when is_integer(x), do: "var#{x}"
  defp symb_var(x) when is_atom(x), do: "var_#{x}"

  defp alias_module(module, module) when is_atom(module),
    do: alias_module(module, [module])
  defp alias_module(module, {module, alias}) when is_atom(module) and is_atom(alias),
    do: alias_module(module, [{module, alias}])
  defp alias_module(module, aliases) when is_list(aliases) do
    mod_split = Module.split(module)
    aliased = for a <- aliases do
      {alias_split, alias_as} = case a do
                                  {m, a} when is_atom(m) and is_atom(a) ->
                                    {Module.split(m), Module.split(a)}
                                  m when is_atom(m) ->
                                    m = Module.split(m)
                                    {m, [List.last(m)]}
                                end

      case :lists.prefix(alias_split, mod_split) do
        false -> module
        true ->
          mod_tail = Enum.drop(mod_split, length(alias_split))
          (alias_as ++ mod_tail)
          |> Module.concat
      end
    end

    [module | aliased]
    |> Enum.sort_by(& &1 |> to_string |> byte_size, &<=/2)
    |> hd
  end

  def inspectx({:exception, :error, exception, stacktrace}, _opts) do
    Exception.format :error, exception, stacktrace
  end
  def inspectx(x, opts) do
    opts = Keyword.get(opts, :inspect_opts, [])
    default_opts = [
      pretty: true,
      limit: :infinity,
      syntax_colors: syntax_colors()
    ]
    inspect x, Keyword.merge(default_opts, opts)
  end

  # added some default colors, since GitHub Actions does not provide a colorized terminal
  # such that some tests fail for the Reporter.
  defp syntax_colors do
    default_colors = [
      atom: :cyan,
      string: :green,
      list: :default_color,
      boolean: :magenta,
      nil: :magenta,
      tuple: :default_color,
      binary: :default_color,
      map: :default_color
    ]
    case IEx.Config.color(:syntax_colors) do
      [] -> default_colors
      kw when is_list(kw) -> kw
      _anything_else -> default_colors
    end
  end
end