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# Redmine - project management software

# Copyright (C) 2006-2011  Jean-Philippe Lang

#

# This program is free software; you can redistribute it and/or

# modify it under the terms of the GNU General Public License

# as published by the Free Software Foundation; either version 2

# of the License, or (at your option) any later version.

#

# This program is distributed in the hope that it will be useful,

# but WITHOUT ANY WARRANTY; without even the implied warranty of

# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

# GNU General Public License for more details.

#

# You should have received a copy of the GNU General Public License

# along with this program; if not, write to the Free Software

# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.

class QueryColumn

  attr_accessor :name, :sortable, :groupable, :default_order

  include Redmine::I18n

  def initialize(name, options={})

    self.name = name

    self.sortable = options[:sortable]

    self.groupable = options[:groupable] || false

    if groupable == true

      self.groupable = name.to_s

    end

    self.default_order = options[:default_order]

    @caption_key = options[:caption] || "field_#{name}"

  end

  def caption

    l(@caption_key)

  end

  # Returns true if the column is sortable, otherwise false

  def sortable?

    !@sortable.nil?

  end

  def sortable

    @sortable.is_a?(Proc) ? @sortable.call : @sortable

  end

  def value(issue)

    issue.send name

  end

  def css_classes

    name

  end

end

class QueryCustomFieldColumn < QueryColumn

  def initialize(custom_field)

    self.name = "cf_#{custom_field.id}".to_sym

    self.sortable = custom_field.order_statement || false

    if %w(list date bool int).include?(custom_field.field_format)

      self.groupable = custom_field.order_statement

    end

    self.groupable ||= false

    @cf = custom_field

  end

  def caption

    @cf.name

  end

  def custom_field

    @cf

  end

  def value(issue)

    cv = issue.custom_values.detect {|v| v.custom_field_id == @cf.id}

    cv && @cf.cast_value(cv.value)

  end

  def css_classes

    @css_classes ||= "#{name} #{@cf.field_format}"

  end

end

class Query < ActiveRecord::Base

  class StatementInvalid < ::ActiveRecord::StatementInvalid

  end

  belongs_to :project

  belongs_to :user

  serialize :filters

  serialize :column_names

  serialize :sort_criteria, Array

  attr_protected :project_id, :user_id

  validates_presence_of :name, :on => :save

  validates_length_of :name, :maximum => 255

  validate :validate_query_filters

  @@operators = { "="   => :label_equals,

                  "!"   => :label_not_equals,

                  "o"   => :label_open_issues,

                  "c"   => :label_closed_issues,

                  "!*"  => :label_none,

                  "*"   => :label_all,

                  ">="  => :label_greater_or_equal,

                  "<="  => :label_less_or_equal,

                  "><"  => :label_between,

                  "<t+" => :label_in_less_than,

                  ">t+" => :label_in_more_than,

                  "t+"  => :label_in,

                  "t"   => :label_today,

                  "w"   => :label_this_week,

                  ">t-" => :label_less_than_ago,

                  "<t-" => :label_more_than_ago,

                  "t-"  => :label_ago,

                  "~"   => :label_contains,

                  "!~"  => :label_not_contains }

  cattr_reader :operators

  @@operators_by_filter_type = { :list => [ "=", "!" ],

                                 :list_status => [ "o", "=", "!", "c", "*" ],

                                 :list_optional => [ "=", "!", "!*", "*" ],

                                 :list_subprojects => [ "*", "!*", "=" ],

                                 :date => [ "=", ">=", "<=", "><", "<t+", ">t+", "t+", "t", "w", ">t-", "<t-", "t-", "!*", "*" ],

                                 :date_past => [ "=", ">=", "<=", "><", ">t-", "<t-", "t-", "t", "w", "!*", "*" ],

                                 :string => [ "=", "~", "!", "!~" ],

                                 :text => [  "~", "!~" ],

                                 :integer => [ "=", ">=", "<=", "><", "!*", "*" ],

                                 :float => [ "=", ">=", "<=", "><", "!*", "*" ] }

  cattr_reader :operators_by_filter_type

  @@available_columns = [

    QueryColumn.new(:project, :sortable => "#{Project.table_name}.name", :groupable => true),

    QueryColumn.new(:tracker, :sortable => "#{Tracker.table_name}.position", :groupable => true),

    QueryColumn.new(:parent, :sortable => ["#{Issue.table_name}.root_id", "#{Issue.table_name}.lft ASC"], :default_order => 'desc', :caption => :field_parent_issue),

    QueryColumn.new(:status, :sortable => "#{IssueStatus.table_name}.position", :groupable => true),

    QueryColumn.new(:priority, :sortable => "#{IssuePriority.table_name}.position", :default_order => 'desc', :groupable => true),

    QueryColumn.new(:subject, :sortable => "#{Issue.table_name}.subject"),

    QueryColumn.new(:author, :sortable => lambda {User.fields_for_order_statement("authors")}, :groupable => true),

    QueryColumn.new(:assigned_to, :sortable => lambda {User.fields_for_order_statement}, :groupable => true),

    QueryColumn.new(:updated_on, :sortable => "#{Issue.table_name}.updated_on", :default_order => 'desc'),

    QueryColumn.new(:category, :sortable => "#{IssueCategory.table_name}.name", :groupable => true),

    QueryColumn.new(:fixed_version, :sortable => ["#{Version.table_name}.effective_date", "#{Version.table_name}.name"], :default_order => 'desc', :groupable => true),

    QueryColumn.new(:start_date, :sortable => "#{Issue.table_name}.start_date"),

    QueryColumn.new(:due_date, :sortable => "#{Issue.table_name}.due_date"),

    QueryColumn.new(:estimated_hours, :sortable => "#{Issue.table_name}.estimated_hours"),

    QueryColumn.new(:done_ratio, :sortable => "#{Issue.table_name}.done_ratio", :groupable => true),

    QueryColumn.new(:created_on, :sortable => "#{Issue.table_name}.created_on", :default_order => 'desc'),

  ]

  cattr_reader :available_columns

  named_scope :visible, lambda {|*args|

    user = args.shift || User.current

    base = Project.allowed_to_condition(user, :view_issues, *args)

    user_id = user.logged? ? user.id : 0

    {

      :conditions => ["(#{table_name}.project_id IS NULL OR (#{base})) AND (#{table_name}.is_public = ? OR #{table_name}.user_id = ?)", true, user_id],

      :include => :project

    }

  }

  def initialize(attributes = nil)

    super attributes

    self.filters ||= { 'status_id' => {:operator => "o", :values => [""]} }

  end

  def after_initialize

    # Store the fact that project is nil (used in #editable_by?)

    @is_for_all = project.nil?

  end

  def validate_query_filters

    filters.each_key do |field|

      if values_for(field)

        case type_for(field)

        when :integer

          errors.add(label_for(field), :invalid) if values_for(field).detect {|v| v.present? && !v.match(/^\d+$/) }

        when :float

          errors.add(label_for(field), :invalid) if values_for(field).detect {|v| v.present? && !v.match(/^\d+(\.\d*)?$/) }

        when :date, :date_past

          case operator_for(field)

          when "=", ">=", "<=", "><"

            errors.add(label_for(field), :invalid) if values_for(field).detect {|v| v.present? && (!v.match(/^\d{4}-\d{2}-\d{2}$/) || (Date.parse(v) rescue nil).nil?) }

          when ">t-", "<t-", "t-"

            errors.add(label_for(field), :invalid) if values_for(field).detect {|v| v.present? && !v.match(/^\d+$/) }

          end

        end

      end

      errors.add label_for(field), :blank unless

          # filter requires one or more values

          (values_for(field) and !values_for(field).first.blank?) or

          # filter doesn't require any value

          ["o", "c", "!*", "*", "t", "w"].include? operator_for(field)

    end if filters

  end

  # Returns true if the query is visible to +user+ or the current user.

  def visible?(user=User.current)

    (project.nil? || user.allowed_to?(:view_issues, project)) && (self.is_public? || self.user_id == user.id)

  end

  def editable_by?(user)

    return false unless user

    # Admin can edit them all and regular users can edit their private queries

    return true if user.admin? || (!is_public && self.user_id == user.id)

    # Members can not edit public queries that are for all project (only admin is allowed to)

    is_public && !@is_for_all && user.allowed_to?(:manage_public_queries, project)

  end

  def available_filters

    return @available_filters if @available_filters

    trackers = project.nil? ? Tracker.find(:all, :order => 'position') : project.rolled_up_trackers

    @available_filters = { "status_id" => { :type => :list_status, :order => 1, :values => IssueStatus.find(:all, :order => 'position').collect{|s| [s.name, s.id.to_s] } },

                           "tracker_id" => { :type => :list, :order => 2, :values => trackers.collect{|s| [s.name, s.id.to_s] } },

                           "priority_id" => { :type => :list, :order => 3, :values => IssuePriority.all.collect{|s| [s.name, s.id.to_s] } },

                           "subject" => { :type => :text, :order => 8 },

                           "created_on" => { :type => :date_past, :order => 9 },

                           "updated_on" => { :type => :date_past, :order => 10 },

                           "start_date" => { :type => :date, :order => 11 },

                           "due_date" => { :type => :date, :order => 12 },

                           "estimated_hours" => { :type => :float, :order => 13 },

                           "done_ratio" =>  { :type => :integer, :order => 14 }}

    principals = []

    if project

      principals += project.principals.sort

    else

      all_projects = Project.visible.all

      if all_projects.any?

        # members of visible projects

        principals += Principal.active.find(:all, :conditions => ["#{User.table_name}.id IN (SELECT DISTINCT user_id FROM members WHERE project_id IN (?))", all_projects.collect(&:id)]).sort

        # project filter

        project_values = []

        Project.project_tree(all_projects) do |p, level|

          prefix = (level > 0 ? ('--' * level + ' ') : '')

          project_values << ["#{prefix}#{p.name}", p.id.to_s]

        end

        @available_filters["project_id"] = { :type => :list, :order => 1, :values => project_values} unless project_values.empty?

      end

    end

    users = principals.select {|p| p.is_a?(User)}

    assigned_to_values = []

    assigned_to_values << ["<< #{l(:label_me)} >>", "me"] if User.current.logged?

    assigned_to_values += (Setting.issue_group_assignment? ? principals : users).collect{|s| [s.name, s.id.to_s] }

    @available_filters["assigned_to_id"] = { :type => :list_optional, :order => 4, :values => assigned_to_values } unless assigned_to_values.empty?

    author_values = []

    author_values << ["<< #{l(:label_me)} >>", "me"] if User.current.logged?

    author_values += users.collect{|s| [s.name, s.id.to_s] }

    @available_filters["author_id"] = { :type => :list, :order => 5, :values => author_values } unless author_values.empty?

    group_values = Group.all.collect {|g| [g.name, g.id.to_s] }

    @available_filters["member_of_group"] = { :type => :list_optional, :order => 6, :values => group_values } unless group_values.empty?

    role_values = Role.givable.collect {|r| [r.name, r.id.to_s] }

    @available_filters["assigned_to_role"] = { :type => :list_optional, :order => 7, :values => role_values } unless role_values.empty?

    if User.current.logged?

      @available_filters["watcher_id"] = { :type => :list, :order => 15, :values => [["<< #{l(:label_me)} >>", "me"]] }

    end

    if project

      # project specific filters

      categories = project.issue_categories.all

      unless categories.empty?

        @available_filters["category_id"] = { :type => :list_optional, :order => 6, :values => categories.collect{|s| [s.name, s.id.to_s] } }

      end

      versions = project.shared_versions.all

      unless versions.empty?

        @available_filters["fixed_version_id"] = { :type => :list_optional, :order => 7, :values => versions.sort.collect{|s| ["#{s.project.name} - #{s.name}", s.id.to_s] } }

      end

      unless project.leaf?

        subprojects = project.descendants.visible.all

        unless subprojects.empty?

          @available_filters["subproject_id"] = { :type => :list_subprojects, :order => 13, :values => subprojects.collect{|s| [s.name, s.id.to_s] } }

        end

      end

      add_custom_fields_filters(project.all_issue_custom_fields)

    else

      # global filters for cross project issue list

      system_shared_versions = Version.visible.find_all_by_sharing('system')

      unless system_shared_versions.empty?

        @available_filters["fixed_version_id"] = { :type => :list_optional, :order => 7, :values => system_shared_versions.sort.collect{|s| ["#{s.project.name} - #{s.name}", s.id.to_s] } }

      end

      add_custom_fields_filters(IssueCustomField.find(:all, :conditions => {:is_filter => true, :is_for_all => true}))

    end

    @available_filters

  end

  def add_filter(field, operator, values)

    # values must be an array

    return unless values.nil? || values.is_a?(Array)

    # check if field is defined as an available filter

    if available_filters.has_key? field

      filter_options = available_filters[field]

      # check if operator is allowed for that filter

      #if @@operators_by_filter_type[filter_options[:type]].include? operator

      #  allowed_values = values & ([""] + (filter_options[:values] || []).collect {|val| val[1]})

      #  filters[field] = {:operator => operator, :values => allowed_values } if (allowed_values.first and !allowed_values.first.empty?) or ["o", "c", "!*", "*", "t"].include? operator

      #end

      filters[field] = {:operator => operator, :values => (values || [''])}

    end

  end

  def add_short_filter(field, expression)

    return unless expression && available_filters.has_key?(field)

    field_type = available_filters[field][:type]

    @@operators_by_filter_type[field_type].sort.reverse.detect do |operator|

      next unless expression =~ /^#{Regexp.escape(operator)}(.*)$/

      add_filter field, operator, $1.present? ? $1.split('|') : ['']

    end || add_filter(field, '=', expression.split('|'))

  end

  # Add multiple filters using +add_filter+

  def add_filters(fields, operators, values)

    if fields.is_a?(Array) && operators.is_a?(Hash) && (values.nil? || values.is_a?(Hash))

      fields.each do |field|

        add_filter(field, operators[field], values && values[field])

      end

    end

  end

  def has_filter?(field)

    filters and filters[field]

  end

  def type_for(field)

    available_filters[field][:type] if available_filters.has_key?(field)

  end

  def operator_for(field)

    has_filter?(field) ? filters[field][:operator] : nil

  end

  def values_for(field)

    has_filter?(field) ? filters[field][:values] : nil

  end

  def value_for(field, index=0)

    (values_for(field) || [])[index]

  end

  def label_for(field)

    label = available_filters[field][:name] if available_filters.has_key?(field)

    label ||= field.gsub(/\_id$/, "")

  end

  def available_columns

    return @available_columns if @available_columns

    @available_columns = ::Query.available_columns

    @available_columns += (project ?

                            project.all_issue_custom_fields :

                            IssueCustomField.find(:all)

                           ).collect {|cf| QueryCustomFieldColumn.new(cf) }

  end

  def self.available_columns=(v)

    self.available_columns = (v)

  end

  def self.add_available_column(column)

    self.available_columns << (column) if column.is_a?(QueryColumn)

  end

  # Returns an array of columns that can be used to group the results

  def groupable_columns

    available_columns.select {|c| c.groupable}

  end

  # Returns a Hash of columns and the key for sorting

  def sortable_columns

    {'id' => "#{Issue.table_name}.id"}.merge(available_columns.inject({}) {|h, column|

                                               h[column.name.to_s] = column.sortable

                                               h

                                             })

  end

  def columns

    # preserve the column_names order

    (has_default_columns? ? default_columns_names : column_names).collect do |name|

       available_columns.find { |col| col.name == name }

    end.compact

  end

  def default_columns_names

    @default_columns_names ||= begin

      default_columns = Setting.issue_list_default_columns.map(&:to_sym)

      project.present? ? default_columns : [:project] | default_columns

    end

  end

  def column_names=(names)

    if names

      names = names.select {|n| n.is_a?(Symbol) || !n.blank? }

      names = names.collect {|n| n.is_a?(Symbol) ? n : n.to_sym }

      # Set column_names to nil if default columns

      if names == default_columns_names

        names = nil

      end

    end

    write_attribute(:column_names, names)

  end

  def has_column?(column)

    column_names && column_names.include?(column.name)

  end

  def has_default_columns?

    column_names.nil? || column_names.empty?

  end

  def sort_criteria=(arg)

    c = []

    if arg.is_a?(Hash)

      arg = arg.keys.sort.collect {|k| arg[k]}

    end

    c = arg.select {|k,o| !k.to_s.blank?}.slice(0,3).collect {|k,o| [k.to_s, o == 'desc' ? o : 'asc']}

    write_attribute(:sort_criteria, c)

  end

  def sort_criteria

    read_attribute(:sort_criteria) || []

  end

  def sort_criteria_key(arg)

    sort_criteria && sort_criteria[arg] && sort_criteria[arg].first

  end

  def sort_criteria_order(arg)

    sort_criteria && sort_criteria[arg] && sort_criteria[arg].last

  end

  # Returns the SQL sort order that should be prepended for grouping

  def group_by_sort_order

    if grouped? && (column = group_by_column)

      column.sortable.is_a?(Array) ?

        column.sortable.collect {|s| "#{s} #{column.default_order}"}.join(',') :

        "#{column.sortable} #{column.default_order}"

    end

  end

  # Returns true if the query is a grouped query

  def grouped?

    !group_by_column.nil?

  end

  def group_by_column

    groupable_columns.detect {|c| c.groupable && c.name.to_s == group_by}

  end

  def group_by_statement

    group_by_column.try(:groupable)

  end

  def project_statement

    project_clauses = []

    if project && !project.descendants.active.empty?

      ids = [project.id]

      if has_filter?("subproject_id")

        case operator_for("subproject_id")

        when '='

          # include the selected subprojects

          ids += values_for("subproject_id").each(&:to_i)

        when '!*'

          # main project only

        else

          # all subprojects

          ids += project.descendants.collect(&:id)

        end

      elsif Setting.display_subprojects_issues?

        ids += project.descendants.collect(&:id)

      end

      project_clauses << "#{Project.table_name}.id IN (%s)" % ids.join(',')

    elsif project

      project_clauses << "#{Project.table_name}.id = %d" % project.id

    end

    project_clauses.any? ? project_clauses.join(' AND ') : nil

  end

  def statement

    # filters clauses

    filters_clauses = []

    filters.each_key do |field|

      next if field == "subproject_id"

      v = values_for(field).clone

      next unless v and !v.empty?

      operator = operator_for(field)

      # "me" value subsitution

      if %w(assigned_to_id author_id watcher_id).include?(field)

        if v.delete("me")

          if User.current.logged?

            v.push(User.current.id.to_s)

            v += User.current.group_ids.map(&:to_s) if field == 'assigned_to_id'

          else

            v.push("0")

          end

        end

      end

      if field =~ /^cf_(\d+)$/

        # custom field

        filters_clauses << sql_for_custom_field(field, operator, v, $1)

      elsif respond_to?("sql_for_#{field}_field")

        # specific statement

        filters_clauses << send("sql_for_#{field}_field", field, operator, v)

      else

        # regular field

        filters_clauses << '(' + sql_for_field(field, operator, v, Issue.table_name, field) + ')'

      end

    end if filters and valid?

    filters_clauses << project_statement

    filters_clauses.reject!(&:blank?)

    filters_clauses.any? ? filters_clauses.join(' AND ') : nil

  end

  # Returns the issue count

  def issue_count

    Issue.visible.count(:include => [:status, :project], :conditions => statement)

  rescue ::ActiveRecord::StatementInvalid => e

    raise StatementInvalid.new(e.message)

  end

  # Returns the issue count by group or nil if query is not grouped

  def issue_count_by_group

    r = nil

    if grouped?

      begin

        # Rails will raise an (unexpected) RecordNotFound if there's only a nil group value

        r = Issue.visible.count(:group => group_by_statement, :include => [:status, :project], :conditions => statement)

      rescue ActiveRecord::RecordNotFound

        r = {nil => issue_count}

      end

      c = group_by_column

      if c.is_a?(QueryCustomFieldColumn)

        r = r.keys.inject({}) {|h, k| h[c.custom_field.cast_value(k)] = r[k]; h}

      end

    end

    r

  rescue ::ActiveRecord::StatementInvalid => e

    raise StatementInvalid.new(e.message)

  end

  # Returns the issues

  # Valid options are :order, :offset, :limit, :include, :conditions

  def issues(options={})

    order_option = [group_by_sort_order, options[:order]].reject {|s| s.blank?}.join(',')

    order_option = nil if order_option.blank?

    joins = (order_option && order_option.include?('authors')) ? "LEFT OUTER JOIN users authors ON authors.id = #{Issue.table_name}.author_id" : nil

    Issue.visible.scoped(:conditions => options[:conditions]).find :all, :include => ([:status, :project] + (options[:include] || [])).uniq,

                     :conditions => statement,

                     :order => order_option,

                     :joins => joins,

                     :limit  => options[:limit],

                     :offset => options[:offset]

  rescue ::ActiveRecord::StatementInvalid => e

    raise StatementInvalid.new(e.message)

  end

  # Returns the journals

  # Valid options are :order, :offset, :limit

  def journals(options={})

    Journal.visible.find :all, :include => [:details, :user, {:issue => [:project, :author, :tracker, :status]}],

                       :conditions => statement,

                       :order => options[:order],

                       :limit => options[:limit],

                       :offset => options[:offset]

  rescue ::ActiveRecord::StatementInvalid => e

    raise StatementInvalid.new(e.message)

  end

  # Returns the versions

  # Valid options are :conditions

  def versions(options={})

    Version.visible.scoped(:conditions => options[:conditions]).find :all, :include => :project, :conditions => project_statement

  rescue ::ActiveRecord::StatementInvalid => e

    raise StatementInvalid.new(e.message)

  end

  def sql_for_watcher_id_field(field, operator, value)

    db_table = Watcher.table_name

    "#{Issue.table_name}.id #{ operator == '=' ? 'IN' : 'NOT IN' } (SELECT #{db_table}.watchable_id FROM #{db_table} WHERE #{db_table}.watchable_type='Issue' AND " +

      sql_for_field(field, '=', value, db_table, 'user_id') + ')'

  end

  def sql_for_member_of_group_field(field, operator, value)

    if operator == '*' # Any group

      groups = Group.all

      operator = '=' # Override the operator since we want to find by assigned_to

    elsif operator == "!*"

      groups = Group.all

      operator = '!' # Override the operator since we want to find by assigned_to

    else

      groups = Group.find_all_by_id(value)

    end

    groups ||= []

    members_of_groups = groups.inject([]) {|user_ids, group|

      if group && group.user_ids.present?

        user_ids << group.user_ids

      end

      user_ids.flatten.uniq.compact

    }.sort.collect(&:to_s)

    '(' + sql_for_field("assigned_to_id", operator, members_of_groups, Issue.table_name, "assigned_to_id", false) + ')'

  end

  def sql_for_assigned_to_role_field(field, operator, value)

    case operator

    when "*", "!*" # Member / Not member

      sw = operator == "!*" ? 'NOT' : ''

      nl = operator == "!*" ? "#{Issue.table_name}.assigned_to_id IS NULL OR" : ''

      "(#{nl} #{Issue.table_name}.assigned_to_id #{sw} IN (SELECT DISTINCT #{Member.table_name}.user_id FROM #{Member.table_name}" +

        " WHERE #{Member.table_name}.project_id = #{Issue.table_name}.project_id))"

    when "=", "!"

      role_cond = value.any? ? 

        "#{MemberRole.table_name}.role_id IN (" + value.collect{|val| "'#{connection.quote_string(val)}'"}.join(",") + ")" :

        "1=0"

      sw = operator == "!" ? 'NOT' : ''

      nl = operator == "!" ? "#{Issue.table_name}.assigned_to_id IS NULL OR" : ''

      "(#{nl} #{Issue.table_name}.assigned_to_id #{sw} IN (SELECT DISTINCT #{Member.table_name}.user_id FROM #{Member.table_name}, #{MemberRole.table_name}" +

        " WHERE #{Member.table_name}.project_id = #{Issue.table_name}.project_id AND #{Member.table_name}.id = #{MemberRole.table_name}.member_id AND #{role_cond}))"

    end

  end

  private

  def sql_for_custom_field(field, operator, value, custom_field_id)

    db_table = CustomValue.table_name

    db_field = 'value'

    "#{Issue.table_name}.id IN (SELECT #{Issue.table_name}.id FROM #{Issue.table_name} LEFT OUTER JOIN #{db_table} ON #{db_table}.customized_type='Issue' AND #{db_table}.customized_id=#{Issue.table_name}.id AND #{db_table}.custom_field_id=#{custom_field_id} WHERE " +

      sql_for_field(field, operator, value, db_table, db_field, true) + ')'

  end

  # Helper method to generate the WHERE sql for a +field+, +operator+ and a +value+

  def sql_for_field(field, operator, value, db_table, db_field, is_custom_filter=false)

    sql = ''

    case operator

    when "="

      if value.any?

        case type_for(field)

        when :date, :date_past

          sql = date_clause(db_table, db_field, (Date.parse(value.first) rescue nil), (Date.parse(value.first) rescue nil))

        when :integer

          sql = "#{db_table}.#{db_field} = #{value.first.to_i}"

        when :float

          sql = "#{db_table}.#{db_field} BETWEEN #{value.first.to_f - 1e-5} AND #{value.first.to_f + 1e-5}"

        else

          sql = "#{db_table}.#{db_field} IN (" + value.collect{|val| "'#{connection.quote_string(val)}'"}.join(",") + ")"

        end

      else

        # IN an empty set

        sql = "1=0"

      end

    when "!"

      if value.any?

        sql = "(#{db_table}.#{db_field} IS NULL OR #{db_table}.#{db_field} NOT IN (" + value.collect{|val| "'#{connection.quote_string(val)}'"}.join(",") + "))"

      else

        # NOT IN an empty set

        sql = "1=1"

      end

    when "!*"

      sql = "#{db_table}.#{db_field} IS NULL"

      sql << " OR #{db_table}.#{db_field} = ''" if is_custom_filter

    when "*"

      sql = "#{db_table}.#{db_field} IS NOT NULL"

      sql << " AND #{db_table}.#{db_field} <> ''" if is_custom_filter

    when ">="

      if [:date, :date_past].include?(type_for(field))

        sql = date_clause(db_table, db_field, (Date.parse(value.first) rescue nil), nil)

      else

        if is_custom_filter

          sql = "CAST(#{db_table}.#{db_field} AS decimal(60,3)) >= #{value.first.to_f}"

        else

          sql = "#{db_table}.#{db_field} >= #{value.first.to_f}"

        end

      end

    when "<="

      if [:date, :date_past].include?(type_for(field))

        sql = date_clause(db_table, db_field, nil, (Date.parse(value.first) rescue nil))

      else

        if is_custom_filter

          sql = "CAST(#{db_table}.#{db_field} AS decimal(60,3)) <= #{value.first.to_f}"

        else

          sql = "#{db_table}.#{db_field} <= #{value.first.to_f}"

        end

      end

    when "><"

      if [:date, :date_past].include?(type_for(field))

        sql = date_clause(db_table, db_field, (Date.parse(value[0]) rescue nil), (Date.parse(value[1]) rescue nil))

      else

        if is_custom_filter

          sql = "CAST(#{db_table}.#{db_field} AS decimal(60,3)) BETWEEN #{value[0].to_f} AND #{value[1].to_f}"

        else

          sql = "#{db_table}.#{db_field} BETWEEN #{value[0].to_f} AND #{value[1].to_f}"

        end

      end

    when "o"

      sql = "#{IssueStatus.table_name}.is_closed=#{connection.quoted_false}" if field == "status_id"

    when "c"

      sql = "#{IssueStatus.table_name}.is_closed=#{connection.quoted_true}" if field == "status_id"

    when ">t-"

      sql = relative_date_clause(db_table, db_field, - value.first.to_i, 0)

    when "<t-"

      sql = relative_date_clause(db_table, db_field, nil, - value.first.to_i)

    when "t-"

      sql = relative_date_clause(db_table, db_field, - value.first.to_i, - value.first.to_i)

    when ">t+"

      sql = relative_date_clause(db_table, db_field, value.first.to_i, nil)

    when "<t+"

      sql = relative_date_clause(db_table, db_field, 0, value.first.to_i)

    when "t+"

      sql = relative_date_clause(db_table, db_field, value.first.to_i, value.first.to_i)

    when "t"

      sql = relative_date_clause(db_table, db_field, 0, 0)

    when "w"

      first_day_of_week = l(:general_first_day_of_week).to_i

      day_of_week = Date.today.cwday

      days_ago = (day_of_week >= first_day_of_week ? day_of_week - first_day_of_week : day_of_week + 7 - first_day_of_week)

      sql = relative_date_clause(db_table, db_field, - days_ago, - days_ago + 6)

    when "~"

      sql = "LOWER(#{db_table}.#{db_field}) LIKE '%#{connection.quote_string(value.first.to_s.downcase)}%'"

    when "!~"

      sql = "LOWER(#{db_table}.#{db_field}) NOT LIKE '%#{connection.quote_string(value.first.to_s.downcase)}%'"

    else

      raise "Unknown query operator #{operator}"

    end

    return sql

  end

  def add_custom_fields_filters(custom_fields)

    @available_filters ||= {}

    custom_fields.select(&:is_filter?).each do |field|

      case field.field_format

      when "text"

        options = { :type => :text, :order => 20 }

      when "list"

        options = { :type => :list_optional, :values => field.possible_values, :order => 20}

      when "date"

        options = { :type => :date, :order => 20 }

      when "bool"

        options = { :type => :list, :values => [[l(:general_text_yes), "1"], [l(:general_text_no), "0"]], :order => 20 }

      when "int"

        options = { :type => :integer, :order => 20 }

      when "float"

        options = { :type => :float, :order => 20 }

      when "user", "version"

        next unless project

        options = { :type => :list_optional, :values => field.possible_values_options(project), :order => 20}

      else

        options = { :type => :string, :order => 20 }

      end

      @available_filters["cf_#{field.id}"] = options.merge({ :name => field.name })

    end

  end

  # Returns a SQL clause for a date or datetime field.

  def date_clause(table, field, from, to)

    s = []

    if from

      from_yesterday = from - 1

      from_yesterday_utc = Time.gm(from_yesterday.year, from_yesterday.month, from_yesterday.day)

      s << ("#{table}.#{field} > '%s'" % [connection.quoted_date(from_yesterday_utc.end_of_day)])

    end

    if to

      to_utc = Time.gm(to.year, to.month, to.day)

      s << ("#{table}.#{field} <= '%s'" % [connection.quoted_date(to_utc.end_of_day)])

    end

    s.join(' AND ')

  end

  # Returns a SQL clause for a date or datetime field using relative dates.

  def relative_date_clause(table, field, days_from, days_to)

    date_clause(table, field, (days_from ? Date.today + days_from : nil), (days_to ? Date.today + days_to : nil))

  end

end