<?php

abstract class HeraldAction extends Phobject {

  private $adapter;
  private $viewer;
  private $applyLog = array();

  const STANDARD_NONE = 'standard.none';
  const STANDARD_PHID_LIST = 'standard.phid.list';
  const STANDARD_TEXT = 'standard.text';

  const DO_STANDARD_EMPTY = 'do.standard.empty';
  const DO_STANDARD_NO_EFFECT = 'do.standard.no-effect';
  const DO_STANDARD_INVALID = 'do.standard.invalid';
  const DO_STANDARD_UNLOADABLE = 'do.standard.unloadable';
  const DO_STANDARD_PERMISSION = 'do.standard.permission';
  const DO_STANDARD_INVALID_ACTION = 'do.standard.invalid-action';
  const DO_STANDARD_WRONG_RULE_TYPE = 'do.standard.wrong-rule-type';

  abstract public function getHeraldActionName();
  abstract public function supportsObject($object);
  abstract public function supportsRuleType($rule_type);
  abstract public function applyEffect($object, HeraldEffect $effect);

  abstract public function renderActionDescription($value);

  protected function renderActionEffectDescription($type, $data) {
    return null;
  }

  public function getActionGroupKey() {
    return null;
  }

  public function getActionsForObject($object) {
    return array($this->getActionConstant() => $this);
  }

  protected function getDatasource() {
    throw new PhutilMethodNotImplementedException();
  }

  protected function getDatasourceValueMap() {
    return null;
  }

  public function getHeraldActionStandardType() {
    throw new PhutilMethodNotImplementedException();
  }

  public function getHeraldActionValueType() {
    switch ($this->getHeraldActionStandardType()) {
      case self::STANDARD_NONE:
        return new HeraldEmptyFieldValue();
      case self::STANDARD_TEXT:
        return new HeraldTextFieldValue();
      case self::STANDARD_PHID_LIST:
        $tokenizer = id(new HeraldTokenizerFieldValue())
          ->setKey($this->getHeraldActionName())
          ->setDatasource($this->getDatasource());

        $value_map = $this->getDatasourceValueMap();
        if ($value_map !== null) {
          $tokenizer->setValueMap($value_map);
        }

        return $tokenizer;
    }

    throw new PhutilMethodNotImplementedException();
  }

  public function willSaveActionValue($value) {
    try {
      $type = $this->getHeraldActionStandardType();
    } catch (PhutilMethodNotImplementedException $ex) {
      return $value;
    }

    switch ($type) {
      case self::STANDARD_PHID_LIST:
        return array_keys($value);
    }

    return $value;
  }

  public function getEditorValue(PhabricatorUser $viewer, $target) {
    try {
      $type = $this->getHeraldActionStandardType();
    } catch (PhutilMethodNotImplementedException $ex) {
      return $target;
    }

    switch ($type) {
      case self::STANDARD_PHID_LIST:
        $handles = $viewer->loadHandles($target);
        $handles = iterator_to_array($handles);
        return mpull($handles, 'getName', 'getPHID');
    }

    return $target;
  }

  final public function setAdapter(HeraldAdapter $adapter) {
    $this->adapter = $adapter;
    return $this;
  }

  final public function getAdapter() {
    return $this->adapter;
  }

  final public function setViewer(PhabricatorUser $viewer) {
    $this->viewer = $viewer;
    return $this;
  }

  final public function getViewer() {
    return $this->viewer;
  }

  final public function getActionConstant() {
    $class = new ReflectionClass($this);

    $const = $class->getConstant('ACTIONCONST');
    if ($const === false) {
      throw new Exception(
        pht(
          '"%s" class "%s" must define a "%s" property.',
          __CLASS__,
          get_class($this),
          'ACTIONCONST'));
    }

    $limit = self::getActionConstantByteLimit();
    if (!is_string($const) || (strlen($const) > $limit)) {
      throw new Exception(
        pht(
          '"%s" class "%s" has an invalid "%s" property. Action constants '.
          'must be strings and no more than %s bytes in length.',
          __CLASS__,
          get_class($this),
          'ACTIONCONST',
          new PhutilNumber($limit)));
    }

    return $const;
  }

  final public static function getActionConstantByteLimit() {
    return 64;
  }

  final public static function getAllActions() {
    return id(new PhutilClassMapQuery())
      ->setAncestorClass(__CLASS__)
      ->setUniqueMethod('getActionConstant')
      ->execute();
  }

  protected function logEffect($type, $data = null) {
    if (!is_string($type)) {
      throw new Exception(
        pht(
          'Effect type passed to "%s" must be a scalar string.',
          'logEffect()'));
    }

    $this->applyLog[] = array(
      'type' => $type,
      'data' => $data,
    );

    return $this;
  }

  final public function getApplyTranscript(HeraldEffect $effect) {
    $context = $this->applyLog;
    $this->applyLog = array();
    return new HeraldApplyTranscript($effect, true, $context);
  }

  protected function getActionEffectMap() {
    throw new PhutilMethodNotImplementedException();
  }

  private function getActionEffectSpec($type) {
    $map = $this->getActionEffectMap() + $this->getStandardEffectMap();
    return idx($map, $type, array());
  }

  final public function renderActionEffectIcon($type, $data) {
    $map = $this->getActionEffectSpec($type);
    return idx($map, 'icon');
  }

  final public function renderActionEffectColor($type, $data) {
    $map = $this->getActionEffectSpec($type);
    return idx($map, 'color');
  }

  final public function renderActionEffectName($type, $data) {
    $map = $this->getActionEffectSpec($type);
    return idx($map, 'name');
  }

  protected function renderHandleList($phids) {
    if (!is_array($phids)) {
      return pht('(Invalid List)');
    }

    return $this->getViewer()
      ->renderHandleList($phids)
      ->setAsInline(true)
      ->render();
  }

  protected function loadStandardTargets(
    array $phids,
    array $allowed_types,
    array $current_value) {

    $phids = array_fuse($phids);
    if (!$phids) {
      $this->logEffect(self::DO_STANDARD_EMPTY);
    }

    $current_value = array_fuse($current_value);
    $no_effect = array();
    foreach ($phids as $phid) {
      if (isset($current_value[$phid])) {
        $no_effect[] = $phid;
        unset($phids[$phid]);
      }
    }

    if ($no_effect) {
      $this->logEffect(self::DO_STANDARD_NO_EFFECT, $no_effect);
    }

    if (!$phids) {
      return;
    }

    $allowed_types = array_fuse($allowed_types);
    $invalid = array();
    foreach ($phids as $phid) {
      $type = phid_get_type($phid);
      if ($type == PhabricatorPHIDConstants::PHID_TYPE_UNKNOWN) {
        $invalid[] = $phid;
        unset($phids[$phid]);
        continue;
      }

      if ($allowed_types && empty($allowed_types[$type])) {
        $invalid[] = $phid;
        unset($phids[$phid]);
        continue;
      }
    }

    if ($invalid) {
      $this->logEffect(self::DO_STANDARD_INVALID, $invalid);
    }

    if (!$phids) {
      return;
    }

    $targets = id(new PhabricatorObjectQuery())
      ->setViewer(PhabricatorUser::getOmnipotentUser())
      ->withPHIDs($phids)
      ->execute();
    $targets = mpull($targets, null, 'getPHID');

    $unloadable = array();
    foreach ($phids as $phid) {
      if (empty($targets[$phid])) {
        $unloadable[] = $phid;
        unset($phids[$phid]);
      }
    }

    if ($unloadable) {
      $this->logEffect(self::DO_STANDARD_UNLOADABLE, $unloadable);
    }

    if (!$phids) {
      return;
    }

    $adapter = $this->getAdapter();
    $object = $adapter->getObject();

    if ($object instanceof PhabricatorPolicyInterface) {
      $no_permission = array();
      foreach ($targets as $phid => $target) {
        if (!($target instanceof PhabricatorUser)) {
          continue;
        }

        $can_view = PhabricatorPolicyFilter::hasCapability(
          $target,
          $object,
          PhabricatorPolicyCapability::CAN_VIEW);
        if ($can_view) {
          continue;
        }

        $no_permission[] = $phid;
        unset($targets[$phid]);
      }
    }

    if ($no_permission) {
      $this->logEffect(self::DO_STANDARD_PERMISSION, $no_permission);
    }

    return $targets;
  }

  protected function getStandardEffectMap() {
    return array(
      self::DO_STANDARD_EMPTY => array(
        'icon' => 'fa-ban',
        'color' => 'grey',
        'name' => pht('No Targets'),
      ),
      self::DO_STANDARD_NO_EFFECT => array(
        'icon' => 'fa-circle-o',
        'color' => 'grey',
        'name' => pht('No Effect'),
      ),
      self::DO_STANDARD_INVALID => array(
        'icon' => 'fa-ban',
        'color' => 'red',
        'name' => pht('Invalid Targets'),
      ),
      self::DO_STANDARD_UNLOADABLE => array(
        'icon' => 'fa-ban',
        'color' => 'red',
        'name' => pht('Unloadable Targets'),
      ),
      self::DO_STANDARD_PERMISSION => array(
        'icon' => 'fa-lock',
        'color' => 'red',
        'name' => pht('No Permission'),
      ),
      self::DO_STANDARD_INVALID_ACTION => array(
        'icon' => 'fa-ban',
        'color' => 'red',
        'name' => pht('Invalid Action'),
      ),
      self::DO_STANDARD_WRONG_RULE_TYPE => array(
        'icon' => 'fa-ban',
        'color' => 'red',
        'name' => pht('Wrong Rule Type'),
      ),
    );
  }

  final public function renderEffectDescription($type, $data) {
    $result = $this->renderActionEffectDescription($type, $data);
    if ($result !== null) {
      return $result;
    }

    switch ($type) {
      case self::DO_STANDARD_EMPTY:
        return pht(
          'This action specifies no targets.');
      case self::DO_STANDARD_NO_EFFECT:
        return pht(
          'This action has no effect on %s target(s): %s.',
          new PhutilNumber(count($data)),
          $this->renderHandleList($data));
      case self::DO_STANDARD_INVALID:
        return pht(
          '%s target(s) are invalid or of the wrong type: %s.',
          new PhutilNumber(count($data)),
          $this->renderHandleList($data));
      case self::DO_STANDARD_UNLOADABLE:
        return pht(
          '%s target(s) could not be loaded: %s.',
          new PhutilNumber(count($data)),
          $this->renderHandleList($data));
      case self::DO_STANDARD_PERMISSION:
        return pht(
          '%s target(s) do not have permission to see this object: %s.',
          new PhutilNumber(count($data)),
          $this->renderHandleList($data));
      case self::DO_STANDARD_INVALID_ACTION:
        return pht(
          'No implementation is available for rule "%s".',
          $data);
      case self::DO_STANDARD_WRONG_RULE_TYPE:
        return pht(
          'This action does not support rules of type "%s".',
          $data);
    }

    return null;
  }

}