# Copyright (C) The Arvados Authors. All rights reserved.
#
# SPDX-License-Identifier: AGPL-3.0

module Psych
  module Visitors
    class YAMLTree < Psych::Visitors::Visitor
      def visit_ActiveSupport_Duration o
        seconds = o.to_i
        outstr = ""
        if seconds / 3600 > 0
          outstr += "#{seconds / 3600}h"
          seconds = seconds % 3600
        end
        if seconds / 60 > 0
          outstr += "#{seconds / 60}m"
          seconds = seconds % 60
        end
        if seconds > 0
          outstr += "#{seconds}s"
        end
        if outstr == ""
          outstr = "0s"
        end
        @emitter.scalar outstr, nil, nil, true, false, Nodes::Scalar::ANY
      end

      def visit_URI_Generic o
        @emitter.scalar o.to_s, nil, nil, true, false, Nodes::Scalar::ANY
      end

      def visit_URI_HTTP o
        @emitter.scalar o.to_s, nil, nil, true, false, Nodes::Scalar::ANY
      end

      def visit_Pathname o
        @emitter.scalar o.to_s, nil, nil, true, false, Nodes::Scalar::ANY
      end
    end
  end
end


module Boolean; end
class TrueClass; include Boolean; end
class FalseClass; include Boolean; end

class NonemptyString < String
end

class ConfigLoader
  def initialize
    @config_migrate_map = {}
    @config_types = {}
  end

  def declare_config(assign_to, configtype, migrate_from=nil, migrate_fn=nil)
    if migrate_from
      @config_migrate_map[migrate_from] = migrate_fn || ->(cfg, k, v) {
        ConfigLoader.set_cfg cfg, assign_to, v
      }
    end
    @config_types[assign_to] = configtype
  end


  def migrate_config from_config, to_config
    remainders = {}
    from_config.each do |k, v|
      if @config_migrate_map[k.to_sym]
        @config_migrate_map[k.to_sym].call to_config, k, v
      else
        remainders[k] = v
      end
    end
    remainders
  end

  def coercion_and_check check_cfg, check_nonempty: true
    @config_types.each do |cfgkey, cfgtype|
      cfg = check_cfg
      k = cfgkey
      ks = k.split '.'
      k = ks.pop
      ks.each do |kk|
        cfg = cfg[kk]
        if cfg.nil?
          break
        end
      end

      if cfg.nil?
        raise "missing #{cfgkey}"
      end

      if cfgtype == String and !cfg[k]
        cfg[k] = ""
      end

      if cfgtype == String and cfg[k].is_a? Symbol
        cfg[k] = cfg[k].to_s
      end

      if cfgtype == Pathname and cfg[k].is_a? String

        if cfg[k] == ""
          cfg[k] = Pathname.new("")
        else
          cfg[k] = Pathname.new(cfg[k])
          if !cfg[k].exist?
            raise "#{cfgkey} path #{cfg[k]} does not exist"
          end
        end
      end

      if cfgtype == NonemptyString
        if (!cfg[k] || cfg[k] == "") && check_nonempty
          raise "#{cfgkey} cannot be empty"
        end
        if cfg[k].is_a? String
          next
        end
      end

      if cfgtype == ActiveSupport::Duration
        if cfg[k].is_a? Integer
          cfg[k] = cfg[k].seconds
        elsif cfg[k].is_a? String
          cfg[k] = ConfigLoader.parse_duration(cfg[k], cfgkey: cfgkey)
        end
      end

      if cfgtype == URI
        cfg[k] = URI(cfg[k])
      end

      if cfgtype == Integer && cfg[k].is_a?(String)
        v = cfg[k].sub(/B\s*$/, '')
        if mt = /(-?\d*\.?\d+)\s*([KMGTPE]i?)$/.match(v)
          if mt[1].index('.')
            v = mt[1].to_f
          else
            v = mt[1].to_i
          end
          cfg[k] = v * {
            'K' => 1000,
            'Ki' => 1 << 10,
            'M' => 1000000,
            'Mi' => 1 << 20,
            "G" =>  1000000000,
            "Gi" => 1 << 30,
            "T" =>  1000000000000,
            "Ti" => 1 << 40,
            "P" =>  1000000000000000,
            "Pi" => 1 << 50,
            "E" =>  1000000000000000000,
            "Ei" => 1 << 60,
          }[mt[2]]
        end
      end

      if !cfg[k].is_a? cfgtype
        raise "#{cfgkey} expected #{cfgtype} but was #{cfg[k].class}"
      end
    end
  end

  def self.set_cfg cfg, k, v
    # "foo.bar = baz" --> { cfg["foo"]["bar"] = baz }
    ks = k.split '.'
    k = ks.pop
    ks.each do |kk|
      cfg = cfg[kk]
      if cfg.nil?
        break
      end
    end
    if !cfg.nil?
      cfg[k] = v
    end
  end

  def self.parse_duration(durstr, cfgkey:)
    sign = 1
    if durstr[0] == '-'
      durstr = durstr[1..-1]
      sign = -1
    end
    duration_re = /(\d+(\.\d+)?)(s|m|h)/
    dursec = 0
    while durstr != ""
      mt = duration_re.match durstr
      if !mt
        raise "#{cfgkey} not a valid duration: '#{durstr}', accepted suffixes are s, m, h"
      end
      multiplier = {s: 1, m: 60, h: 3600}
      dursec += (Float(mt[1]) * multiplier[mt[3].to_sym] * sign)
      durstr = durstr[mt[0].length..-1]
    end
    return dursec.seconds
  end

  def self.copy_into_config src, dst
    src.each do |k, v|
      dst.send "#{k}=", self.to_OrderedOptions(v)
    end
  end

  def self.to_OrderedOptions confs
    if confs.is_a? Hash
      opts = ActiveSupport::OrderedOptions.new
      confs.each do |k,v|
        opts[k] = self.to_OrderedOptions(v)
      end
      opts
    elsif confs.is_a? Array
      confs.map { |v| self.to_OrderedOptions v }
    else
      confs
    end
  end

  def self.load path, erb: false
    if File.exist? path
      yaml = IO.read path
      if erb
        yaml = ERB.new(yaml).result(binding)
      end
      YAML.load(yaml, deserialize_symbols: false)
    else
      {}
    end
  end

end