require "rugged"
require "socket"

class Ppl::Adapter::Storage::Git < Ppl::Adapter::Storage

  attr_accessor :disk
  attr_accessor :repository
  attr_accessor :vcard_adapter

  def initialize(disk)
    @disk = disk
    @repository = Rugged::Repository.new(@disk.directory.path)
  end

  def self.create_address_book(path)
    repo = Rugged::Repository.init_at(path, false)
    disk = Ppl::Adapter::Storage::Disk.create_address_book(path)

    git = self.new(disk)
    git.add(".ppl/config")
    git.commit("first commit")
  end

  def load_address_book
    address_book = Ppl::Entity::AddressBook.new

    head = @repository.lookup(@repository.head.target.oid)
    head.tree.each do |file|
      extension = file[:name].slice(-4..-1)
      if extension != ".vcf"
        next
      end
      contact_id = file[:name].slice(0..-5)
      contact    = load_contact(contact_id)
      address_book.contacts.push(contact)
    end

    return address_book
  end

  def load_contact(id)
    begin
      read_contact_from_disk id
    rescue GreenCard::InvalidEncodingError
      raise Ppl::Error::InvalidVcard, "#{id}.vcf contains invalid data"
    end
  end

  def save_contact(contact)
    @disk.save_contact(contact)

    add("#{contact.id}.vcf")
    commit("save_contact(#{contact.id})")
  end

  def delete_contact(contact)
    @repository.index.remove("#{contact.id}.vcf")
    @repository.index.write
    commit("remove_contact(#{contact.id})")
    @disk.delete_contact(contact)
  end


  def add(file)
    @repository.index.add(file)
    @repository.index.write
  end

  def commit(message)
    hash = @repository.index.write_tree
    tree = @repository.lookup hash
    head = nil

    begin
      head = @repository.head
    rescue
    end

    if !head.nil?
      parents    = [ @repository.lookup( @repository.head.target.oid ).oid ]
      update_ref = "HEAD"
    else
      parents    = []
      update_ref = "HEAD"
    end

    begin
      git_config = Rugged::Config.open_global.to_hash
    rescue Rugged::OSError
      git_config = {}
    end

    author = {
      :email => git_config.fetch('user.email', "#{ENV['USER']}@#{Socket.gethostname}"),
      :time  => Time.now,
      :name  => git_config.fetch('user.name', ENV['USER']),
    }

    data = {
      :author     => author,
      :message    => message,
      :committer  => author,
      :tree       => tree,
      :parents    => parents,
      :update_ref => update_ref,
    }

    Rugged::Commit.create(@repository, data)
    true
  end

  def path
    @disk.path
  end

  private

  def read_contact_from_disk(id)
    filename = id + ".vcf"
    target   = @repository.head.target
    blob     = @repository.blob_at(target.oid, filename)
    vcard    = blob.nil? ? nil : blob.content
    contact  = nil

    if !vcard.nil?
      contact    = @vcard_adapter.decode(vcard)
      contact.id = id
    end

    return contact
  end

end