require 'ffi'

module Rust
  extend FFI::Library
  ffi_lib File.expand_path(File.dirname(__FILE__)) + "/rbspy/rbspy.#{RbConfig::CONFIG["DLEXT"]}"
  attach_function :initialize_agent, [:string, :string, :string, :int, :bool, :bool, :bool, :bool, :string], :bool
  attach_function :add_tag, [:uint64, :string, :string], :bool
  attach_function :remove_tag, [:uint64, :string, :string], :bool
  attach_function :drop_agent, [], :bool
end

module Utils
  extend FFI::Library
  ffi_lib File.expand_path(File.dirname(__FILE__)) + "/thread_id/thread_id.#{RbConfig::CONFIG["DLEXT"]}"
  attach_function :thread_id, [], :uint64
end

module Pyroscope
  Config = Struct.new(:application_name, :app_name, :server_address, :auth_token, :sample_rate, :detect_subprocesses, :on_cpu, :report_pid, :report_thread_id, :log_level, :tags) do
    def initialize(*)
      super
      self.application_name ||= ''
      self.server_address ||= 'http://localhost:4040'
      self.auth_token ||= ''
      self.sample_rate ||= 100
      self.detect_subprocesses ||= true
      self.on_cpu ||= true
      self.report_pid ||= false
      self.report_thread_id ||= false
      self.log_level ||= 'info'
      self.tags ||= []
    end
  end

  class << self
    def configure
      @config = Config.new

      # Pass config to the block
      yield @config

      Rust.initialize_agent(
        @config.app_name || @config.application_name,
        @config.server_address,
        @config.auth_token,
        @config.sample_rate,
        @config.detect_subprocesses,
        @config.on_cpu,
        @config.report_pid,
        @config.report_thread_id,
        tags_to_string(@config.tags)
      )
    end

    def tag_wrapper(tags)
      tid = thread_id
      _add_tags(tid, tags)
      begin
        yield
      ensure
        _remove_tags(tid, tags)
      end
    end

    def tag(tags)
      warn("deprecated. Use `Pyroscope.tag_wrapper` instead.")
    end

    def remove_tags(*tags)
      warn("deprecated. Use `Pyroscope.tag_wrapper` instead.")
    end

    # convert tags object to string
    def tags_to_string(tags)
      tags.map { |k, v| "#{k}=#{v}" }.join(',')
    end

    # get thread id
    def thread_id
      return Utils.thread_id
    end

    # add tags
    def _add_tags(thread_id, tags)
      tags.each do |tag_name, tag_value|
        Rust.add_tag(thread_id, tag_name.to_s, tag_value.to_s)
      end
    end

    # remove tags
    def _remove_tags(thread_id, tags)
      tags.each do |tag_name, tag_value|
        Rust.remove_tag(thread_id, tag_name.to_s, tag_value.to_s)
      end
    end

    def drop
      Rust.drop_agent
    end
  end
end