checkbox.opa

/*
    Copyright © 2011 MLstate

    This file is part of OPA.

    OPA is free software: you can redistribute it and/or modify it under the
    terms of the GNU Affero General Public License, version 3, as published by
    the Free Software Foundation.

    OPA 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 Affero General Public License for
    more details.

    You should have received a copy of the GNU Affero General Public License
    along with OPA.  If not, see <http://www.gnu.org/licenses/>.
*/

/**
 * A configurable checkbox widget.
 *
 * @author Frederic Ye, 2010
 * @category WIDGET
 * @destination PUBLIC
 * @stability EXPERIMENTAL
 * @version 0.1
 */

/**
 * {1 About this module}
 *
 * This widget is a checkbox with two states: checked or not.
 *
 * {1 Where should I start?}
 *
 * The simpler way to obtain a checkbox is to use the [WCheckbox.html] 
 * function:
 *
 * {[
 * change_cb(is_checked) =
 *   state_str = if is_checked then "checked" else "unchecked"
 *   Dom.transform([#feedback <- <>Checkbox {state_str}</>])
 *
 * params = {
 *   editable = true
 *   on_change = change_checkbox
 * }
 *
 * <div id=#feedback></div>
 * <div id=#sample_cb>
 *   {WCheckbox.html(WCheckbox.default_config_with_css, "sample_cb", params, 
 *   {value = false})
 * </div>
 * ]}
 *
 * {1 What if I need more?}
 *
 * The default configuration can be modified to customize the checkbox 
 * appearance:
 *
 * {[
 * my_config = {WCheckbox.default_config with
 *   ...
 * }
 * ]}
 */

import stdlib.widgets.core
import stdlib.interactions.editable
import stdlib.components.table

/**
 * {1 Types defined in this module}
 */

/**
 * State of a checkbox.
 */
type WCheckbox.value = bool

/**
 * Parameters of a checkbox.
 */
type WCheckbox.parameters = {
  editable: bool
  on_change: WCheckbox.value -> void
}

/**
 * Configuration of a checkbox.
 */
type WCheckbox.config = {
  prefix_class: option(string)
  stylers: IEditable.stylers
}

WCheckbox = {{

  /*
  * {1 ID shortcuts}
  */

  gen_id(prefix_id:string, suffix:string) =
    "{prefix_id}_checkbox{suffix}"

  checkbox_id(prefix_id:string) =
    gen_id(prefix_id, "")

  /**
   * {1 Configuration}
   */

  /**
   * A default checkbox configuration
   */
  default_config = {
    prefix_class = none
    stylers = IEditable.default_config.stylers
  } : WCheckbox.config

  default_config_with_css(css_prefix:string) = { default_config with
    prefix_class = some(css_prefix)
  } : WCheckbox.config

  /**
   * {1 High-level interface}
   */

  /**
   * Constructs a non-editable checkbox.
   *
   * @param config The configuration of the checkbox.
   * @param prefix_id The unique ID associated to the checkbox.
   * @param init_value The state of the checkbox.
   * @return The checkbox instance, represented by a XHTML value.
   */
  show(config:WCheckbox.config, prefix_id:string, init_value:WCheckbox.value) : xhtml =
    // FIXME: do not copy code: using Xhtml.to_dom ? ...
    // Maybe use another display ?
    html = if init_value then
             <input type="checkbox" readonly="readonly" disabled="disabled" id=#{checkbox_id(prefix_id)} checked="checked"/>
           else
             <input type="checkbox" readonly="readonly" disabled="disabled" id=#{checkbox_id(prefix_id)}/>
    html |> WStyler.add(config.stylers.show, _)

  /**
   * Constructs a checkbox.
   *
   * @param config The configuration of the checkbox.
   * @param prefix_id The unique ID associated to the checkbox.
   * @param parameters Initial parameters of the checkbox
   * @param init_value Initial state of the checkbox
   * @return The checkbox instance, represented by a XHTML value.
   */
  edit(config:WCheckbox.config, prefix_id:string, parameters:WCheckbox.parameters, init_value:WCheckbox.value) : xhtml =
    html = if init_value then
             <input onchange={change_action(config, prefix_id, parameters, _)} type="checkbox" id=#{checkbox_id(prefix_id)} checked="checked"/>
           else
             <input onchange={change_action(config, prefix_id, parameters, _)} type="checkbox" id=#{checkbox_id(prefix_id)}/>
    html |> WStyler.add(config.stylers.edit, _) // |> WCore.add_binds([({change}, change_action)], _) // works only in client mode

  /**
   * Constructs a checkbox, editable or not depending on the given parameters.
   *
   * @param config The configuration of the checkbox.
   * @param prefix_id The unique ID associated to the checkbox.
   * @param parameters Initial parameters of the checkbox.
   * @param init_value Initial state of the checkbox
   * @return The checkbox instance, represented by a XHTML value.
   */
  html(config:WCheckbox.config, prefix_id:string, parameters:WCheckbox.parameters, init_value:IEditable.content(WCheckbox.value)) : xhtml =
    val = match init_value with
          | {~value} -> value
          | _ -> false
    if parameters.editable then
      edit(config, prefix_id, parameters, val)
    else
      show(config, prefix_id, val)

  /**
   * Returns the state of the checkbox (checked or not).
   *
   * @param _config The configuration of the checkbox
   * @param prefix_id The unique ID associated to the checkbox
   * @return A boolean value corresponding to the checkbox state
   */
  parse(_config:WCheckbox.config, prefix_id:string) =
    Dom.is_checked(#{checkbox_id(prefix_id)})

  @private
  change_action(config:WCheckbox.config, prefix_id:string, parameters:WCheckbox.parameters, _event:Dom.event) =
    checked = parse(config, prefix_id)
    parameters.on_change(checked)

}}

WCheckCell(box : WCheckbox.value -> 'a, unbox : option('a) -> WCheckbox.value) : CTable.Cell.widget('a) =

  internal_parameters(config:CTable.Cell.config, id:string, editable:bool) = {
    editable = editable
    on_change = val -> config.on_change(id, box(val))
  }

  internal_html(config:CTable.Cell.config, id:string, val:IEditable.content(WCheckbox.value), editable:bool) =
    internal_config = { WCheckbox.default_config with
                        stylers.editable = config.style }
    WCheckbox.html(internal_config, id, internal_parameters(config, id, editable), val)
    |> WStyler.add(config.style, _)

  internal_set_value(config:CTable.Cell.config, id:string, val:IEditable.content(WCheckbox.value)) =
    Dom.transform([#{id} <- internal_html(config, id, val, config.openable)])

  internal_parse(_config:CTable.Cell.config, id:string) =
    parse_fun = id -> some(WCheckbox.parse(WCheckbox.default_config, id))
    IEditable.parse_content(id, parse_fun(_))

{

  html(config:CTable.Cell.config, id:string, val:IEditable.content('a)) : xhtml =
    val = match val with
          | {~value} -> {value=unbox(Option.some(value))}
          | {missing_value} -> {missing_value}
          | {invalid_value=opt_val} ->
            match opt_val with
            | {~some} -> {invalid_value=Option.some(unbox(Option.some(some)))}
            | {none} -> {invalid_value=Option.none}
            end
          end
    internal_html(config, id, val, config.openable)

  do_open(config:CTable.Cell.config, id:string) : void =
    Dom.transform([#{id} <- internal_html(config, id, internal_parse(config, id), true)])

  do_close(config:CTable.Cell.config, id:string) : void =
    internal_set_value(config, id, internal_parse(config, id))

  set_value(config:CTable.Cell.config, id:string, val:'a) : void =
    internal_set_value(config, id, {value=unbox(Option.some(val))})

  set_invalid_value(config:CTable.Cell.config, id:string, val:option('a)) =
    match val with
    | {~some} -> internal_set_value(config, id, {invalid_value=Option.some(unbox(Option.some(some)))})
    | {none} -> internal_set_value(config, id, {invalid_value=Option.none})

  clear_value(config:CTable.Cell.config, id:string) : void =
     internal_set_value(config, id, {missing_value})

  parse(config:CTable.Cell.config, id:string) : IEditable.content('a) =
    match internal_parse(config, id) with
    | {~value} -> {value=box(value)}
    | {missing_value} -> {missing_value}
    | {invalid_value=opt_val} ->
      match opt_val with
      | {~some} -> {invalid_value=Option.some(box(some))}
      | {none} -> {invalid_value=Option.none}
      end
    end

}