defmodule Mix.Tasks.Log.Search do
  @moduledoc """
  Search and filter log entries from files.

  ## Usage

      mix log.search <path> [options]

  ## Options

      --level    Filter by log level (info, warn, error, debug)
      --format   Filter by log format (morgan, java, elixir, nginx)
      --source   Filter by source (substring match)
      --grep     Filter by message content (substring match, case-insensitive)
      --limit    Maximum number of results (default: 50)

  ## Examples

      mix log.search logs/app.log
      mix log.search logs/app.log --level error
      mix log.search logs/app.log --format java --level warn
      mix log.search logs/ --grep "timeout" --limit 10
  """
  @shortdoc "Search and filter log entries"

  use Mix.Task

  alias TelemetryData.FileReader

  @impl Mix.Task
  def run(args) do
    {opts, positional, _} =
      OptionParser.parse(args,
        strict: [level: :string, format: :string, source: :string, grep: :string, limit: :integer]
      )

    path = List.first(positional) || "logs/"
    limit = Keyword.get(opts, :limit, 50)

    entries = load_entries(path)
    filtered = apply_filters(entries, opts)
    total = length(filtered)
    display = Enum.take(filtered, limit)

    Mix.shell().info("\n#{IO.ANSI.bright()}Found #{total} entries#{IO.ANSI.reset()} (showing #{min(limit, total)})\n")

    Enum.each(display, &print_entry/1)

    if total > limit do
      Mix.shell().info("\n... #{total - limit} more entries (use --limit to see more)")
    end
  end

  defp load_entries(path) do
    if File.dir?(path) do
      case FileReader.read_dir(path) do
        {:ok, entries} -> entries
        {:error, reason} -> Mix.raise("Failed to read directory #{path}: #{reason}")
      end
    else
      case FileReader.read_file(path) do
        {:ok, entries} -> entries
        {:error, reason} -> Mix.raise("Failed to read file #{path}: #{reason}")
      end
    end
  end

  defp apply_filters(entries, opts) do
    entries
    |> maybe_filter(:level, opts[:level])
    |> maybe_filter(:format, opts[:format])
    |> maybe_filter(:source, opts[:source])
    |> maybe_filter(:grep, opts[:grep])
  end

  defp maybe_filter(entries, _key, nil), do: entries

  defp maybe_filter(entries, :level, level) do
    level = String.downcase(level)
    Enum.filter(entries, &(&1.level == level))
  end

  defp maybe_filter(entries, :format, format) do
    format = String.to_existing_atom(format)
    Enum.filter(entries, &(&1.format == format))
  end

  defp maybe_filter(entries, :source, source) do
    source_down = String.downcase(source)
    Enum.filter(entries, fn entry ->
      entry.source && String.contains?(String.downcase(entry.source), source_down)
    end)
  end

  defp maybe_filter(entries, :grep, pattern) do
    pattern_down = String.downcase(pattern)
    Enum.filter(entries, fn entry ->
      String.contains?(String.downcase(entry.message), pattern_down)
    end)
  end

  defp print_entry(entry) do
    level_tag = colorize_level(entry.level)
    format_tag = IO.ANSI.cyan() <> "[#{entry.format}]" <> IO.ANSI.reset()
    source = if entry.source, do: IO.ANSI.faint() <> " #{entry.source}" <> IO.ANSI.reset(), else: ""

    Mix.shell().info("#{level_tag} #{format_tag}#{source} #{entry.timestamp}")
    Mix.shell().info("  #{entry.message}\n")
  end

  defp colorize_level("error"), do: IO.ANSI.red() <> "[ERROR]" <> IO.ANSI.reset()
  defp colorize_level("warn"), do: IO.ANSI.yellow() <> "[WARN] " <> IO.ANSI.reset()
  defp colorize_level("warning"), do: IO.ANSI.yellow() <> "[WARN] " <> IO.ANSI.reset()
  defp colorize_level("info"), do: IO.ANSI.green() <> "[INFO] " <> IO.ANSI.reset()
  defp colorize_level("debug"), do: IO.ANSI.faint() <> "[DEBUG]" <> IO.ANSI.reset()
  defp colorize_level(other), do: "[#{String.upcase(other)}]"
end