class Bundler::PubGrub::VersionRange

def self.any
  new
end

def self.empty
  EMPTY
end

def ==(other)
  self.class == other.class &&
    min == other.min &&
    max == other.max &&
    include_min == other.include_min &&
    include_max == other.include_max
end

def allows_all?(other)
  return true if other.empty?
  if other.is_a?(VersionUnion)
    return VersionUnion.new([self]).allows_all?(other)
  end
  return false if max && !other.max
  return false if min && !other.min
  if min
    case min <=> other.min
    when -1
    when 0
      return false if !include_min && other.include_min
    when 1
      return false
    end
  end
  if max
    case max <=> other.max
    when -1
      return false
    when 0
      return false if !include_max && other.include_max
    when 1
    end
  end
  true
end

def any?
  !min && !max
end

def compare_version(version)
  if min
    case version <=> min
    when -1
      return -1
    when 0
      return -1 if !include_min
    when 1
    end
  end
  if max
    case version <=> max
    when -1
    when 0
      return 1 if !include_max
    when 1
      return 1
    end
  end
  0
end

def constraints
  return ["any"] if any?
  return ["= #{min}"] if min.to_s == max.to_s
  c = []
  c << "#{include_min ? ">=" : ">"} #{min}" if min
  c << "#{include_max ? "<=" : "<"} #{max}" if max
  c
end

def contiguous_to?(other)
  return false if other.empty?
  intersects?(other) ||
    (min == other.max && (include_min || other.include_max)) ||
    (max == other.min && (include_max || other.include_min))
end

def empty?
  false
end

def eql?(other)
  if other.is_a?(VersionRange)
    !other.empty? &&
      min.eql?(other.min) &&
      max.eql?(other.max) &&
      include_min.eql?(other.include_min) &&
      include_max.eql?(other.include_max)
  else
    ranges.eql?(other.ranges)
  end
end

def hash
  @hash ||= min.hash ^ max.hash ^ include_min.hash ^ include_max.hash
end

def include?(version)
  compare_version(version) == 0
end

def initialize(min: nil, max: nil, include_min: false, include_max: false, name: nil)
  @min = min
  @max = max
  @include_min = include_min
  @include_max = include_max
  @name = name
end

def inspect
  "#<#{self.class} #{to_s}>"
end

def intersect(other)
  return other if other.empty?
  return other.intersect(self) if other.is_a?(VersionUnion)
  min_range =
    if !min
      other
    elsif !other.min
      self
    else
      case min <=> other.min
      when 0
        include_min ? other : self
      when -1
        other
      when 1
        self
      end
    end
  max_range =
    if !max
      other
    elsif !other.max
      self
    else
      case max <=> other.max
      when 0
        include_max ? other : self
      when -1
        self
      when 1
        other
      end
    end
  if !min_range.equal?(max_range) && min_range.min && max_range.max
    case min_range.min <=> max_range.max
    when -1
    when 0
      if !min_range.include_min || !max_range.include_max
        return EMPTY
      end
    when 1
      return EMPTY
    end
  end
  VersionRange.new(
    min: min_range.min,
    include_min: min_range.include_min,
    max: max_range.max,
    include_max: max_range.include_max
  )
end

def intersects?(other)
  return false if other.empty?
  return other.intersects?(self) if other.is_a?(VersionUnion)
  !strictly_lower?(other) && !strictly_higher?(other)
end

def invert
  return self.class.empty if any?
  low = VersionRange.new(max: min, include_max: !include_min)
  high = VersionRange.new(min: max, include_min: !include_max)
  if !min
    high
  elsif !max
    low
  else
    low.union(high)
  end
end

def partition_versions(versions)
  min_index =
    if !min || versions.empty?
      0
    elsif include_min?
      (0..versions.size).bsearch { |i| versions[i].nil? || versions[i] >= min }
    else
      (0..versions.size).bsearch { |i| versions[i].nil? || versions[i] > min }
    end
  lower = versions.slice(0, min_index)
  versions = versions.slice(min_index, versions.size)
  max_index =
    if !max || versions.empty?
      versions.size
    elsif include_max?
      (0..versions.size).bsearch { |i| versions[i].nil? || versions[i] > max }
    else
      (0..versions.size).bsearch { |i| versions[i].nil? || versions[i] >= max }
    end
  [
    lower,
    versions.slice(0, max_index),
    versions.slice(max_index, versions.size)
  ]
end

def ranges
  [self]
end

def select_versions(versions)
  return versions if any?
  partition_versions(versions)[1]
end

def span(other)
  return self if other.empty?
  min_range =
    if !min
      self
    elsif !other.min
      other
    else
      case min <=> other.min
      when 0
        include_min ? self : other
      when -1
        self
      when 1
        other
      end
    end
  max_range =
    if !max
      self
    elsif !other.max
      other
    else
      case max <=> other.max
      when 0
        include_max ? self : other
      when -1
        other
      when 1
        self
      end
    end
  VersionRange.new(
    min: min_range.min,
    include_min: min_range.include_min,
    max: max_range.max,
    include_max: max_range.include_max
  )
end

def strictly_higher?(other)
  other.strictly_lower?(self)
end

def strictly_lower?(other)
  return false if !max || !other.min
  case max <=> other.min
  when 0
    !include_max || !other.include_min
  when -1
    true
  when 1
    false
  end
end

def to_s
  @name ||= constraints.join(", ")
end

def union(other)
  return other.union(self) if other.is_a?(VersionUnion)
  if contiguous_to?(other)
    span(other)
  else
    VersionUnion.union([self, other])
  end
end

def upper_invert
  return self.class.empty unless max
  VersionRange.new(min: max, include_min: !include_max)
end