#!/usr/bin/env ruby
require 'rexml/document'
require 'net/http'
require 'net/https'
require 'sqlite3'
require 'json'

dbfile_base = 'delicious_bkp_'
rcfile_base = '.delicious_bkp.rc'

agent = 'del.icio.us backup v0.2.1'

schema = <<EOF
create table bookmarks (
    hash char(32) primary key,
    url varchar(1024),
    title varchar(1024),
    note varchar(2048),
    time timestamp
);
create table tags (hash char(32), tag varchar(1024));
create index ix_tags_hash on tags (hash);
create index ix_tags_tag on tags (tag);
EOF
insert_url = 'insert into bookmarks (hash, url, title, note, time) ' +
             'values (?, ?, ?, ?, ?);'
insert_tag = 'insert into tags (hash, tag) values (?, ?);'


rcfile_path = File.join(ENV['HOME'], rcfile_base)
if (not FileTest.exist?(rcfile_path))
	puts "\nERROR: rc file not found!\n\n"
	puts "Create a file " + rcfile_path + " containing the following line:"
	puts "{ \"user\": \"username\", \"pass\": \"password\", \"dir\": \"/path/to/bkp\", \"max_bkp\": 0}\n\n"
	exit -1
end
rcfile = File.open(rcfile_path)
perms = sprintf("%o", rcfile.stat().mode)[-4..-1]
if (perms != "0600")
	puts "\nERROR: rc file permissions are not safe!\n\n"
	exit -1
end
begin
j = JSON.parse(rcfile.read())
rescue JSON::ParserError
	puts "\nERROR: bad syntax in rc file\n\n"
	exit -1
end
['user', 'pass', 'dir', 'max_bkp'].each { |key|
	if (not j.has_key?(key))
		puts "\nERROR: field " + key + " doesn't exist in rc file!\n\n"
		exit -1
	end
}
if (not FileTest.directory?(j['dir']))
	puts "\nERROR: Specified directory does not exist!\n\n"
	exit -1
end

dbfile_base = dbfile_base + j['user'] + "_"
dbfile_name = dbfile_base + Time.now.strftime("%Y-%m-%d.db")
dbfile_path = File.join(j['dir'], dbfile_name)
if (FileTest.exist?(dbfile_path))
	puts "Backup " + dbfile_name + " exists, exiting."
	exit 0
end

http = Net::HTTP.new('api.del.icio.us', 443)
http.use_ssl = true
xml = http.start { |http|
    req = Net::HTTP::Get.new('/v1/posts/all', {'User-Agent' => agent})
    req.basic_auth(j['user'], j['pass'])
    http.request(req).body
}

doc = REXML::Document.new(xml)

SQLite3::Database.open(dbfile_path).transaction { |db|
    db.execute_batch(schema)
    db.prepare(insert_url) { |url_stmt|
        db.prepare(insert_tag) { |tag_stmt|
            doc.elements.each('posts/post') { |el|
                url_stmt.execute(el.attributes['hash'],
                    el.attributes['href'], el.attributes['description'],
                    el.attributes['extended'], el.attributes['time'])
                el.attributes['tag'].split(' ').each { |tag|
                    tag_stmt.execute(el.attributes['hash'], tag)
                }
            }
        }
    }
}

if (j['max_bkp'] > 0)
	d = Dir.new(j['dir'])
	b = []
	re = Regexp.new(dbfile_base + "[0-9][0-9][0-9][0-9]-[0-9][0-9]-[0-9][0-9]\.db")
	d.each {|entry| if re.match(entry) then b.push(entry) end }
	if b.nitems > j['max_bkp']
        	b.sort()[0, (b.nitems - j['max_bkp'])].each {|olddb|
	                File.unlink(File.join(j['dir'], olddb))
        	}
	end
end