rustdds 0.4.5

use log::{error};

use std::{
  collections::{BTreeMap, HashMap, btree_map::Range},
  cmp::max,
};

use crate::dds::{
  typedesc::TypeDesc,
  qos::{QosPolicies, QosPolicyBuilder, policy::ResourceLimits },
};
use crate::structure::time::Timestamp;

use super::{
  topic_kind::TopicKind,
  cache_change::{CacheChange},
};
use std::ops::Bound::{Included, Excluded};

/// DDSCache contains all cacheCahanges that are produced by participant or recieved by participant.
/// Each topic that is been published or been subscribed are contained in separate TopicCaches.
/// One TopicCache cotains only DDSCacheChanges of one serialized IDL datatype.
/// -> all cachechanges in same TopicCache can be serialized/deserialized same way.
/// Topic/TopicCache is identified by its name, which must be unique in the whole Domain.
#[derive(Debug)]
pub struct DDSCache {
  topic_caches: HashMap<String, TopicCache>,
}

impl DDSCache {
  pub fn new() -> DDSCache {
    DDSCache {
      topic_caches: HashMap::new(),
    }
  }

  pub fn add_new_topic(
    &mut self,
    topic_name: &String,
    topic_kind: TopicKind,
    topic_data_type: TypeDesc,
  ) -> bool {
    if self.topic_caches.contains_key(topic_name) {
      false
    } else {
      self.topic_caches.insert(
        topic_name.to_string(),
        TopicCache::new(topic_kind, topic_data_type),
      );
      true
    }
  }

  pub fn remove_topic(&mut self, topic_name: &String) {
    if self.topic_caches.contains_key(topic_name) {
      self.topic_caches.remove(topic_name);
    }
  }

  pub fn get_topic_qos_mut(&mut self, topic_name: &String) -> Option<&mut QosPolicies> {
    if self.topic_caches.contains_key(topic_name) {
      Some(&mut self.topic_caches.get_mut(topic_name).unwrap().topic_qos)
    } else {
      None
    }
  }

  pub fn get_topic_qos(&self, topic_name: &String) -> Option<&QosPolicies> {
    if self.topic_caches.contains_key(topic_name) {
      Some(&self.topic_caches.get(topic_name).unwrap().topic_qos)
    } else {
      None
    }
  }

  pub fn from_topic_get_change(&self, topic_name: &String, instant: &Timestamp) 
    -> Option<&CacheChange> 
  {
    self.topic_caches.get(topic_name).map( |tc| tc.get_change(instant) ).flatten()
  }


  /// Removes cacheChange permanently
  pub fn from_topic_remove_change(
    &mut self,
    topic_name: &String,
    instant: &Timestamp,
  ) -> Option<CacheChange> {
    match self.topic_caches.get_mut(topic_name) {
      Some(tc) => tc.remove_change(instant),
      None => {
        error!("Topic: '{:?}' is not in DDSCache", topic_name); 
        None  
      }
    }
  }

  /// Removes cacheChange permanently
  pub fn from_topic_remove_before(&mut self, topic_name: &String, instant: Timestamp) 
  {
    match self.topic_caches.get_mut(topic_name) {
      Some(tc) => tc.remove_changes_before(instant),
      None => {
        error!("Topic: '{:?}' is not in DDSCache", topic_name); 
      }
    }
  }


  pub fn from_topic_get_all_changes(&self, topic_name: &str) -> Vec<(&Timestamp, &CacheChange)> {
    match self.topic_caches.get(topic_name) {
      Some(r) => r.get_all_changes(),
      None => vec![],
    }
  }

  pub fn from_topic_get_changes_in_range(
    &self,
    topic_name: &String,
    start_instant: &Timestamp,
    end_instant: &Timestamp,
  ) -> Vec<(&Timestamp, &CacheChange)> {
    if self.topic_caches.contains_key(topic_name) {
      return self
        .topic_caches
        .get(topic_name)
        .unwrap()
        .get_changes_in_range(start_instant, end_instant);
    } else {
      return vec![];
    }
  }

  pub fn to_topic_add_change(
    &mut self,
    topic_name: &String,
    instant: &Timestamp,
    cache_change: CacheChange,
  ) {
    if self.topic_caches.contains_key(topic_name) {
      return self
        .topic_caches
        .get_mut(topic_name)
        .unwrap()
        .add_change(instant, cache_change);
    } else {
      error!("Topic: '{:?}' is not added to DDSCache", topic_name);
    }
  }
}

#[derive(Debug)]
pub struct TopicCache {
  topic_data_type: TypeDesc,
  topic_kind: TopicKind,
  topic_qos: QosPolicies,
  history_cache: DDSHistoryCache,
}

impl TopicCache {
  pub fn new(topic_kind: TopicKind, topic_data_type: TypeDesc) -> TopicCache {
    TopicCache {
      topic_data_type: topic_data_type,
      topic_kind: topic_kind,
      topic_qos: QosPolicyBuilder::new().build(),
      history_cache: DDSHistoryCache::new(),
    }
  }

  pub fn get_change(&self, instant: &Timestamp) -> Option<&CacheChange> {
    self.history_cache.get_change(instant)
  }

  pub fn add_change(&mut self, instant: &Timestamp, cache_change: CacheChange) {
    self.history_cache.add_change(instant, cache_change)
  }

  pub fn get_all_changes(&self) -> Vec<(&Timestamp, &CacheChange)> {
    self.history_cache.get_all_changes()
  }

  pub fn get_changes_in_range(
    &self,
    start_instant: &Timestamp,
    end_instant: &Timestamp,
  ) -> Vec<(&Timestamp, &CacheChange)> {
    self
      .history_cache
      .get_range_of_changes_vec(start_instant, end_instant)
  }

  ///Removes and returns value if it was found
  pub fn remove_change(&mut self, instant: &Timestamp) -> Option<CacheChange> {
    self.history_cache.remove_change(instant)
  }

  pub fn remove_changes_before(&mut self, instant: Timestamp) {
    // Look up some Topic-specific resource limit
    // and remove earliest samples until we are within limit.
    // This prevents cache from groving indefinetly.
    let max_keep_samples = self.topic_qos.resource_limits()
        .unwrap_or( ResourceLimits {
                    max_samples: 1024,
                    max_instances: 1024,
                    max_samples_per_instance: 64,
                  })
        .max_samples;
    // TODO: We cannot currently keep track of instance counts, because TopicCache or
    // DDSCache below do not know about instances.
    let remove_count = self.history_cache.changes.len() as i32 - max_keep_samples as i32;
    let split_key = 
          *self.history_cache.changes.keys()
            .take(max(0,remove_count) as usize + 1)
            .last()
            .map( |lim| max(lim,&instant) )
            .unwrap_or(&instant);
    self.history_cache.remove_changes_before(split_key)
  }

}

// This is contained in a TopicCache
#[derive(Debug)]
pub struct DDSHistoryCache {
  pub(crate) changes: BTreeMap<Timestamp, CacheChange>,
}

impl DDSHistoryCache {
  pub fn new() -> DDSHistoryCache {
    DDSHistoryCache {
      changes: BTreeMap::new(),
    }
  }

  pub fn add_change(&mut self, instant: &Timestamp, cache_change: CacheChange) {
    let result = self.changes.insert(*instant, cache_change);
    if result.is_none() {
      // all is good. timestamp was not inserted before.
    } else {
      // If this happens cahce changes were created at exactly same instant.
      error!("DDSHistoryCache already contained element with key {:?} !!!", instant);
    }
  }

  pub fn get_all_changes(&self) -> Vec<(&Timestamp, &CacheChange)> {
    self.changes.iter().collect()
  }

  pub fn get_change(&self, instant: &Timestamp) -> Option<&CacheChange> {
    self.changes.get(instant)
  }

  pub fn get_range_of_changes(
    &self,
    start_instant: &Timestamp,
    end_instant: &Timestamp,
  ) -> Range<Timestamp, CacheChange> {
    self
      .changes
      .range((Included(start_instant), Included(end_instant)))
  }

  pub fn get_range_of_changes_vec(
    &self,
    start_instant: &Timestamp,
    end_instant: &Timestamp,
  ) -> Vec<(&Timestamp, &CacheChange)> {
    let mut changes: Vec<(&Timestamp, &CacheChange)> = vec![];
    for (i, c) in self
      .changes
      .range((Excluded(start_instant), Included(end_instant)))
    {
      changes.push((i, c));
    }
    changes
  }


  /// Removes and returns value if it was found
  pub fn remove_change(&mut self, instant: &Timestamp) -> Option<CacheChange> {
    self.changes.remove(instant)
  }

  pub fn remove_changes_before(&mut self, instant: Timestamp) {
    self.changes = self.changes.split_off(&instant);
  }
}

// -----------------------------------------------------------------------
// -----------------------------------------------------------------------
// -----------------------------------------------------------------------

#[cfg(test)]
mod tests {
  use std::sync::{Arc, RwLock};
  use std::{thread};
  use log::info;

  use super::DDSCache;
  use crate::{
    dds::{
      data_types::DDSTimestamp, ddsdata::DDSData, data_types::DDSDuration, typedesc::TypeDesc,
    },
    messages::submessages::submessage_elements::serialized_payload::{SerializedPayload},
    structure::{
      cache_change::CacheChange, topic_kind::TopicKind, guid::GUID, sequence_number::SequenceNumber,
    },
  };

  #[test]
  fn create_dds_cache() {
    let cache = Arc::new(RwLock::new(DDSCache::new()));
    let topic_name = &String::from("ImJustATopic");
    let change1 = CacheChange::new(
      GUID::GUID_UNKNOWN,
      SequenceNumber::from(1),
      DDSData::new(SerializedPayload::default()),
    );
    cache.write().unwrap().add_new_topic(
      topic_name,
      TopicKind::WithKey,
      TypeDesc::new("IDontKnowIfThisIsNecessary"),
    );
    cache
      .write()
      .unwrap()
      .to_topic_add_change(topic_name, &DDSTimestamp::now(), change1);

    let pointerToCache1 = cache.clone();

    thread::spawn(move || {
      let topic_name = &String::from("ImJustATopic");
      let cahange2 = CacheChange::new(
        GUID::GUID_UNKNOWN,
        SequenceNumber::from(1),
        DDSData::new(SerializedPayload::default()),
      );
      pointerToCache1.write().unwrap().to_topic_add_change(
        topic_name,
        &DDSTimestamp::now(),
        cahange2,
      );
      let cahange3 = CacheChange::new(
        GUID::GUID_UNKNOWN,
        SequenceNumber::from(2),
        DDSData::new(SerializedPayload::default()),
      );
      pointerToCache1.write().unwrap().to_topic_add_change(
        topic_name,
        &DDSTimestamp::now(),
        cahange3,
      );
    })
    .join()
    .unwrap();

    cache
      .read()
      .unwrap()
      .from_topic_get_change(topic_name, &DDSTimestamp::now());
    assert_eq!(
      cache
        .read()
        .unwrap()
        .from_topic_get_changes_in_range(
          topic_name,
          &(DDSTimestamp::now() - DDSDuration::from_secs(23)),
          &DDSTimestamp::now()
        )
        .len(),
      3
    );
    info!(
      "{:?}",
      cache.read().unwrap().from_topic_get_changes_in_range(
        topic_name,
        &(DDSTimestamp::now() - DDSDuration::from_secs(23)),
        &DDSTimestamp::now()
      )
    );
  }
}