//
// imag - the personal information management suite for the commandline
// Copyright (C) 2015-2019 Matthias Beyer <mail@beyermatthias.de> and contributors
//
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation; version
// 2.1 of the License.
//
// This library 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
// Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
//

use std::collections::BTreeMap;
#[cfg(test)]
use std::path::PathBuf;

use libimagstore::storeid::StoreId;
use libimagstore::storeid::IntoStoreId;
use libimagstore::store::Entry;
use libimagstore::store::Store;
use libimagerror::errors::ErrorMsg as EM;

use toml_query::read::TomlValueReadExt;
use toml_query::insert::TomlValueInsertExt;
use failure::ResultExt;
use failure::Fallible as Result;
use failure::Error;
use failure::err_msg;

use self::iter::LinkIter;
use self::iter::IntoValues;

use toml::Value;

#[derive(Eq, PartialOrd, Ord, Hash, Debug, Clone)]
pub enum Link {
    Id          { link: StoreId },
    Annotated   { link: StoreId, annotation: String },
}

impl Link {

    pub fn exists(&self) -> Result<bool> {
        match *self {
            Link::Id { ref link }             => link.exists(),
            Link::Annotated { ref link, .. }  => link.exists(),
        }
        .map_err(From::from)
    }

    pub fn to_str(&self) -> Result<String> {
        match *self {
            Link::Id { ref link }             => link.to_str(),
            Link::Annotated { ref link, .. }  => link.to_str(),
        }
        .map_err(From::from)
    }


    fn eq_store_id(&self, id: &StoreId) -> bool {
        match self {
            &Link::Id { link: ref s }             => s.eq(id),
            &Link::Annotated { link: ref s, .. }  => s.eq(id),
        }
    }

    /// Get the StoreId inside the Link, which is always present
    pub fn get_store_id(&self) -> &StoreId {
        match self {
            &Link::Id { link: ref s }             => s,
            &Link::Annotated { link: ref s, .. }  => s,
        }
    }

    /// Helper wrapper around Link for StoreId
    fn without_base(self) -> Link {
        match self {
            Link::Id { link: s } => Link::Id { link: s.without_base() },
            Link::Annotated { link: s, annotation: ann } =>
                Link::Annotated { link: s.without_base(), annotation: ann },
        }
    }

    /// Helper wrapper around Link for StoreId
    #[cfg(test)]
    fn with_base(self, pb: PathBuf) -> Link {
        match self {
            Link::Id { link: s } => Link::Id { link: s.with_base(pb) },
            Link::Annotated { link: s, annotation: ann } =>
                Link::Annotated { link: s.with_base(pb), annotation: ann },
        }
    }

    fn to_value(&self) -> Result<Value> {
        match self {
            &Link::Id { link: ref s } =>
                s.to_str()
                .map(Value::String)
                .context(EM::ConversionError)
                .map_err(Error::from),
            &Link::Annotated { ref link, annotation: ref anno } => {
                link.to_str()
                    .map(Value::String)
                    .context(EM::ConversionError)
                    .map_err(Error::from)
                    .map(|link| {
                        let mut tab = BTreeMap::new();

                        tab.insert("link".to_owned(),       link);
                        tab.insert("annotation".to_owned(), Value::String(anno.clone()));
                        Value::Table(tab)
                    })
            }
        }
    }

}

impl ::std::cmp::PartialEq for Link {
    fn eq(&self, other: &Self) -> bool {
        match (self, other) {
            (&Link::Id { link: ref a }, &Link::Id { link: ref b }) => a.eq(&b),
            (&Link::Annotated { link: ref a, annotation: ref ann1 },
             &Link::Annotated { link: ref b, annotation: ref ann2 }) =>
                (a, ann1).eq(&(b, ann2)),
            _ => false,
        }
    }
}

impl From<StoreId> for Link {

    fn from(s: StoreId) -> Link {
        Link::Id { link: s }
    }
}

impl Into<StoreId> for Link {
    fn into(self) -> StoreId {
        match self {
            Link::Id { link }            => link,
            Link::Annotated { link, .. } => link,
        }
    }
}

impl IntoStoreId for Link {
    fn into_storeid(self) -> Result<StoreId> {
        match self {
            Link::Id { link }            => Ok(link),
            Link::Annotated { link, .. } => Ok(link),
        }
    }
}

impl AsRef<StoreId> for Link {
    fn as_ref(&self) -> &StoreId {
        match self {
            &Link::Id { ref link }            => &link,
            &Link::Annotated { ref link, .. } => &link,
        }
    }
}

pub trait InternalLinker {

    /// Get the internal links from the implementor object
    fn get_internal_links(&self) -> Result<LinkIter>;

    /// Set the internal links for the implementor object
    fn set_internal_links(&mut self, links: Vec<&mut Entry>) -> Result<LinkIter>;

    /// Add an internal link to the implementor object
    fn add_internal_link(&mut self, link: &mut Entry) -> Result<()>;

    /// Remove an internal link from the implementor object
    fn remove_internal_link(&mut self, link: &mut Entry) -> Result<()>;

    /// Remove _all_ internal links
    fn unlink(&mut self, store: &Store) -> Result<()>;

    /// Add internal annotated link
    fn add_internal_annotated_link(&mut self, link: &mut Entry, annotation: String) -> Result<()>;
}

pub mod iter {
    use std::vec::IntoIter;
    use super::Link;

    use failure::Error;
    use failure::Fallible as Result;
    use failure::ResultExt;
    use toml::Value;
    use itertools::Itertools;

    use libimagstore::store::Store;
    use libimagstore::store::FileLockEntry;
    use libimagerror::errors::ErrorMsg as EM;

    pub struct LinkIter(IntoIter<Link>);

    impl LinkIter {

        pub fn new(v: Vec<Link>) -> LinkIter {
            LinkIter(v.into_iter())
        }

        pub fn into_getter(self, store: &Store) -> GetIter {
            GetIter(self.0, store)
        }

    }

    impl Iterator for LinkIter {
        type Item = Link;

        fn next(&mut self) -> Option<Self::Item> {
            self.0.next()
        }
    }

    pub trait IntoValues {
        fn into_values(self) -> Vec<Result<Value>>;
    }

    impl<I: Iterator<Item = Link>> IntoValues for I {
        fn into_values(self) -> Vec<Result<Value>> {
            self.map(|s| s.without_base())
                .unique()
                .sorted()
                .into_iter() // Cannot sort toml::Value, hence uglyness here
                .map(|link| link.to_value().context(EM::ConversionError).map_err(Error::from))
                .collect()
        }
    }

    /// An Iterator that `Store::get()`s the Entries from the store while consumed
    pub struct GetIter<'a>(IntoIter<Link>, &'a Store);

    impl<'a> GetIter<'a> {
        pub fn new(i: IntoIter<Link>, store: &'a Store) -> GetIter<'a> {
            GetIter(i, store)
        }

        /// Turn this iterator into a LinkGcIter, which `Store::delete()`s entries that are not
        /// linked to any other entry.
        pub fn delete_unlinked(self) -> DeleteUnlinkedIter<'a> {
            DeleteUnlinkedIter(self)
        }

        /// Turn this iterator into a FilterLinksIter that removes all entries that are not linked
        /// to any other entry, by filtering them out the iterator.
        ///
        /// This does _not_ remove the entries from the store.
        pub fn without_unlinked(self) -> FilterLinksIter<'a> {
            FilterLinksIter::new(self, Box::new(|links: &[Link]| links.len() > 0))
        }

        /// Turn this iterator into a FilterLinksIter that removes all entries that have less than
        /// `n` links to any other entries.
        ///
        /// This does _not_ remove the entries from the store.
        pub fn with_less_than_n_links(self, n: usize) -> FilterLinksIter<'a> {
            FilterLinksIter::new(self, Box::new(move |links: &[Link]| links.len() < n))
        }

        /// Turn this iterator into a FilterLinksIter that removes all entries that have more than
        /// `n` links to any other entries.
        ///
        /// This does _not_ remove the entries from the store.
        pub fn with_more_than_n_links(self, n: usize) -> FilterLinksIter<'a> {
            FilterLinksIter::new(self, Box::new(move |links: &[Link]| links.len() > n))
        }

        /// Turn this iterator into a FilterLinksIter that removes all entries where the predicate
        /// `F` returns false
        ///
        /// This does _not_ remove the entries from the store.
        pub fn filtered_for_links(self, f: Box<Fn(&[Link]) -> bool>) -> FilterLinksIter<'a> {
            FilterLinksIter::new(self, f)
        }

        pub fn store(&self) -> &Store {
            self.1
        }
    }

    impl<'a> Iterator for GetIter<'a> {
        type Item = Result<FileLockEntry<'a>>;

        fn next(&mut self) -> Option<Self::Item> {
            self.0.next().and_then(|id| match self.1.get(id) {
                Ok(None)    => None,
                Ok(Some(x)) => Some(Ok(x)),
                Err(e)      => Some(Err(e).map_err(From::from)),
            })
        }

    }

    /// An iterator helper that has a function F.
    ///
    /// If the function F returns `false` for the number of links, the entry is ignored, else it is
    /// taken.
    pub struct FilterLinksIter<'a>(GetIter<'a>, Box<Fn(&[Link]) -> bool>);

    impl<'a> FilterLinksIter<'a> {
        pub fn new(gi: GetIter<'a>, f: Box<Fn(&[Link]) -> bool>) -> FilterLinksIter<'a> {
            FilterLinksIter(gi, f)
        }
    }

    impl<'a> Iterator for FilterLinksIter<'a> {
        type Item = Result<FileLockEntry<'a>>;

        fn next(&mut self) -> Option<Self::Item> {
            use internal::InternalLinker;

            loop {
                match self.0.next() {
                    Some(Ok(fle)) => {
                        let links = match fle.get_internal_links() {
                            Err(e) => return Some(Err(e)),
                            Ok(links) => links.collect::<Vec<_>>(),
                        };
                        if !(self.1)(&links) {
                            continue;
                        } else {
                            return Some(Ok(fle));
                        }
                    },
                    Some(Err(e)) => return Some(Err(e)),
                    None => break,
                }
            }
            None
        }

    }

    /// An iterator that removes all Items from the iterator that are not linked anymore by calling
    /// `Store::delete()` on them.
    ///
    /// It yields only items which are somehow linked to another entry
    ///
    /// # Warning
    ///
    /// Deletes entries from the store.
    ///
    pub struct DeleteUnlinkedIter<'a>(GetIter<'a>);

    impl<'a> Iterator for DeleteUnlinkedIter<'a> {
        type Item = Result<FileLockEntry<'a>>;

        fn next(&mut self) -> Option<Self::Item> {
            use internal::InternalLinker;

            loop {
                match self.0.next() {
                    Some(Ok(fle)) => {
                        let links = match fle.get_internal_links() {
                            Err(e) => return Some(Err(e)),
                            Ok(links) => links,
                        };
                        if links.count() == 0 {
                            match self.0.store().delete(fle.get_location().clone()) {
                                Ok(x)  => x,
                                Err(e) => return Some(Err(e).map_err(From::from)),
                            }
                        } else {
                            return Some(Ok(fle));
                        }
                    },
                    Some(Err(e)) => return Some(Err(e)),
                    None => break,
                }
            }
            None
        }

    }

}

impl InternalLinker for Entry {

    fn get_internal_links(&self) -> Result<LinkIter> {
        debug!("Getting internal links");
        trace!("Getting internal links from header of '{}' = {:?}", self.get_location(), self.get_header());
        let res = self
            .get_header()
            .read("links.internal")
            .map_err(Error::from)
            .context(EM::EntryHeaderReadError)
            .context(EM::EntryHeaderError)
            .map_err(Error::from)
            .map(|r| r.cloned());
        process_rw_result(res)
    }

    /// Set the links in a header and return the old links, if any.
    fn set_internal_links(&mut self, links: Vec<&mut Entry>) -> Result<LinkIter> {
        use internal::iter::IntoValues;

        debug!("Setting internal links");

        let self_location = self.get_location().clone();
        let mut new_links = vec![];

        for link in links {
            if let Err(e) = add_foreign_link(link, self_location.clone()) {
                return Err(e);
            }
            new_links.push(link.get_location().clone().into());
        }

        let new_links = LinkIter::new(new_links)
                             .into_values()
                             .into_iter()
                             .fold(Ok(vec![]), |acc: Result<Vec<_>>, elem| {
                                acc.and_then(move |mut v| {
                                    v.push(elem.context(EM::ConversionError)?);
                                    Ok(v)
                                })
                            })?;
        let res = self
            .get_header_mut()
            .insert("links.internal", Value::Array(new_links))
            .map_err(Error::from)
            .context(EM::EntryHeaderReadError)
            .map_err(Error::from);
        process_rw_result(res)
    }

    fn add_internal_link(&mut self, link: &mut Entry) -> Result<()> {
        debug!("Adding internal link: {:?}", link);
        let location = link.get_location().clone().into();
        add_internal_link_with_instance(self, link, location)
    }

    fn remove_internal_link(&mut self, link: &mut Entry) -> Result<()> {
        debug!("Removing internal link: {:?}", link);
        let own_loc   = self.get_location().clone().without_base();
        let other_loc = link.get_location().clone().without_base();

        debug!("Removing internal link from {:?} to {:?}", own_loc, other_loc);

        link.get_internal_links()
            .and_then(|links| {
                debug!("Rewriting own links for {:?}, without {:?}", other_loc, own_loc);
                let links = links.filter(|l| !l.eq_store_id(&own_loc));
                rewrite_links(link.get_header_mut(), links)
            })
            .and_then(|_| {
                self.get_internal_links()
                    .and_then(|links| {
                        debug!("Rewriting own links for {:?}, without {:?}", own_loc, other_loc);
                        let links = links.filter(|l| !l.eq_store_id(&other_loc));
                        rewrite_links(self.get_header_mut(), links)
                    })
            })
    }

    fn unlink(&mut self, store: &Store) -> Result<()> {
        for id in self.get_internal_links()?.map(|l| l.get_store_id().clone()) {
            match store.get(id).map_err(Error::from)? {
                Some(mut entry) => self.remove_internal_link(&mut entry)?,
                None            => return Err(err_msg("Link target does not exist")),
            }
        }

        Ok(())
    }

    fn add_internal_annotated_link(&mut self, link: &mut Entry, annotation: String) -> Result<()> {
        let new_link = Link::Annotated {
            link: link.get_location().clone(),
            annotation: annotation,
        };

        add_internal_link_with_instance(self, link, new_link)
    }

}

fn add_internal_link_with_instance(this: &mut Entry, link: &mut Entry, instance: Link) -> Result<()> {
    debug!("Adding internal link from {:?} to {:?}", this.get_location(), instance);

    add_foreign_link(link, this.get_location().clone())
        .and_then(|_| {
            this.get_internal_links()
                .and_then(|links| {
                    let links = links.chain(LinkIter::new(vec![instance]));
                    rewrite_links(this.get_header_mut(), links)
                })
        })
}

fn rewrite_links<I: Iterator<Item = Link>>(header: &mut Value, links: I) -> Result<()> {
    let links = links.into_values()
                     .into_iter()
                     .fold(Ok(vec![]), |acc: Result<Vec<_>>, elem| {
                        acc.and_then(move |mut v| {
                            v.push(elem.context(EM::ConversionError)?);
                            Ok(v)
                        })
                     })?;

    debug!("Setting new link array: {:?}", links);
    let process = header
        .insert("links.internal", Value::Array(links))
        .map_err(Error::from)
        .context(EM::EntryHeaderReadError)
        .map_err(Error::from);
    process_rw_result(process).map(|_| ())
}

/// When Linking A -> B, the specification wants us to link back B -> A.
/// This is a helper function which does this.
fn add_foreign_link(target: &mut Entry, from: StoreId) -> Result<()> {
    debug!("Linking back from {:?} to {:?}", target.get_location(), from);
    target.get_internal_links()
        .and_then(|links| {
            let links = links
                             .chain(LinkIter::new(vec![from.into()]))
                             .into_values()
                             .into_iter()
                             .fold(Ok(vec![]), |acc: Result<Vec<_>>, elem| {
                                acc.and_then(move |mut v| {
                                    v.push(elem.context(EM::ConversionError)?);
                                    Ok(v)
                                })
                             })?;
            debug!("Setting links in {:?}: {:?}", target.get_location(), links);

            let res = target
                .get_header_mut()
                .insert("links.internal", Value::Array(links))
                .map_err(Error::from)
                .context(EM::EntryHeaderReadError)
                .map_err(Error::from);

            process_rw_result(res).map(|_| ())
        })
}

fn process_rw_result(links: Result<Option<Value>>) -> Result<LinkIter> {
    use std::path::PathBuf;

    let links = match links {
        Err(e) => {
            debug!("RW action on store failed. Generating LinkError");
            return Err(e).context(EM::EntryHeaderReadError).map_err(Error::from)
        },
        Ok(None) => {
            debug!("We got no value from the header!");
            return Ok(LinkIter::new(vec![]))
        },
        Ok(Some(Value::Array(l))) => l,
        Ok(Some(_)) => {
            debug!("We expected an Array for the links, but there was a non-Array!");
            return Err(err_msg("Link type error"));
        }
    };

    if !links.iter().all(|l| is_match!(*l, Value::String(_)) || is_match!(*l, Value::Table(_))) {
        debug!("At least one of the Values which were expected in the Array of links is not a String or a Table!");
        debug!("Generating LinkError");
        return Err(err_msg("Existing Link type error"));
    }

    let links : Vec<Link> = links.into_iter()
        .map(|link| {
            debug!("Matching the link: {:?}", link);
            match link {
                Value::String(s) => StoreId::new_baseless(PathBuf::from(s))
                    .map(|s| Link::Id { link: s })
                    .map_err(From::from)
                    ,
                Value::Table(mut tab) => {
                    debug!("Destructuring table");
                    if !tab.contains_key("link")
                    || !tab.contains_key("annotation") {
                        debug!("Things missing... returning Error instance");
                        Err(err_msg("Link parser error"))
                    } else {
                        let link = tab.remove("link")
                            .ok_or(err_msg("Link parser: field missing"))?;

                        let anno = tab.remove("annotation")
                            .ok_or(err_msg("Link parser: Field missing"))?;

                        debug!("Ok, here we go with building a Link::Annotated");
                        match (link, anno) {
                            (Value::String(link), Value::String(anno)) => {
                                StoreId::new_baseless(PathBuf::from(link))
                                    .map_err(From::from)
                                    .map(|link| {
                                        Link::Annotated {
                                            link: link,
                                            annotation: anno,
                                        }
                                    })
                            },
                            _ => Err(err_msg("Link parser: Field type error")),
                        }
                    }
                }
                _ => unreachable!(),
            }
        })
        .collect::<Result<Vec<Link>>>()?;

    debug!("Ok, the RW action was successful, returning link vector now!");
    Ok(LinkIter::new(links))
}

pub mod store_check {
    use libimagstore::store::Store;

    use failure::ResultExt;
    use failure::Fallible as Result;
    use failure::Error;
    use failure::err_msg;

    pub trait StoreLinkConsistentExt {
        fn check_link_consistency(&self) -> Result<()>;
    }

    impl StoreLinkConsistentExt for Store {
        fn check_link_consistency(&self) -> Result<()> {
            use std::collections::HashMap;

            use internal::InternalLinker;

            use libimagstore::storeid::StoreId;
            use libimagutil::debug_result::DebugResult;

            // Helper data structure to collect incoming and outgoing links for each StoreId
            #[derive(Debug, Default)]
            struct Linking {
                outgoing: Vec<StoreId>,
                incoming: Vec<StoreId>,
            }

            // Helper function to aggregate the Link network
            //
            // This function aggregates a HashMap which maps each StoreId object in the store onto
            // a Linking object, which contains a list of StoreIds which this entry links to and a
            // list of StoreIds which link to the current one.
            //
            // The lambda returns an error if something fails
            let aggregate_link_network = |store: &Store| -> Result<HashMap<StoreId, Linking>> {
                store
                    .entries()?
                    .into_get_iter()
                    .fold(Ok(HashMap::new()), |map, element| {
                        map.and_then(|mut map| {
                            debug!("Checking element = {:?}", element);
                            let entry = element?.ok_or_else(|| err_msg("TODO: Not yet handled"))?;

                            debug!("Checking entry = {:?}", entry.get_location());

                            let internal_links = entry
                                .get_internal_links()?
                                .into_getter(store); // get the FLEs from the Store

                            let mut linking = Linking::default();
                            for internal_link in internal_links {
                                debug!("internal link = {:?}", internal_link);

                                linking.outgoing.push(internal_link?.get_location().clone());
                                linking.incoming.push(entry.get_location().clone());
                            }

                            map.insert(entry.get_location().clone(), linking);
                            Ok(map)
                        })
                    })
            };

            // Helper to check whethre all StoreIds in the network actually exists
            //
            // Because why not?
            let all_collected_storeids_exist = |network: &HashMap<StoreId, Linking>| -> Result<()> {
                for (id, _) in network.iter() {
                    if is_match!(self.get(id.clone()), Ok(Some(_))) {
                        debug!("Exists in store: {:?}", id);

                        if !id.exists()? {
                            warn!("Does exist in store but not on FS: {:?}", id);
                            return Err(err_msg("Link target does not exist"))
                        }
                    } else {
                        warn!("Does not exist in store: {:?}", id);
                        return Err(err_msg("Link target does not exist"))
                    }
                }

                Ok(())
            };

            // Helper function to create a SLCECD::OneDirectionalLink error object
            let mk_one_directional_link_err = |src: StoreId, target: StoreId| -> Error {
                Error::from(format_err!("Dead link: {} -> {}",
                                        src.local_display_string(),
                                        target.local_display_string()))
            };

            // Helper lambda to check whether the _incoming_ links of each entry actually also
            // appear in the _outgoing_ list of the linked entry
            let incoming_links_exists_as_outgoing_links =
                |src: &StoreId, linking: &Linking, network: &HashMap<StoreId, Linking>| -> Result<()> {
                    for link in linking.incoming.iter() {
                        // Check whether the links which are _incoming_ on _src_ are outgoing
                        // in each of the links in the incoming list.
                        let incoming_consistent = network.get(link)
                            .map(|l| l.outgoing.contains(src))
                            .unwrap_or(false);

                        if !incoming_consistent {
                            return Err(mk_one_directional_link_err(src.clone(), link.clone()))
                        }
                    }

                    Ok(())
                };

            // Helper lambda to check whether the _outgoing links of each entry actually also
            // appear in the _incoming_ list of the linked entry
            let outgoing_links_exist_as_incoming_links =
                |src: &StoreId, linking: &Linking, network: &HashMap<StoreId, Linking>| -> Result<()> {
                    for link in linking.outgoing.iter() {
                        // Check whether the links which are _outgoing_ on _src_ are incoming
                        // in each of the links in the outgoing list.
                        let outgoing_consistent = network.get(link)
                            .map(|l| l.incoming.contains(src))
                            .unwrap_or(false);

                        if !outgoing_consistent {
                            return Err(mk_one_directional_link_err(link.clone(), src.clone()))
                        }
                    }

                    Ok(())
                };

            aggregate_link_network(&self)
                .map_dbg_str("Aggregated")
                .map_dbg(|nw| {
                    let mut s = String::new();
                    for (k, v) in nw {
                        s.push_str(&format!("{}\n in: {:?}\n out: {:?}", k, v.incoming, v.outgoing));
                    }
                    s
                })
                .and_then(|nw| {
                    all_collected_storeids_exist(&nw)
                        .map(|_| nw)
                        .context(err_msg("Link handling error"))
                        .map_err(Error::from)
                })
                .and_then(|nw| {
                    for (id, linking) in nw.iter() {
                        incoming_links_exists_as_outgoing_links(id, linking, &nw)?;
                        outgoing_links_exist_as_incoming_links(id, linking, &nw)?;
                    }
                    Ok(())
                })
                .map(|_| ())
        }
    }

}

#[cfg(test)]
mod test {
    use std::path::PathBuf;
    use std::sync::Arc;

    use libimagstore::store::Store;

    use super::InternalLinker;
    use super::Link;

    fn setup_logging() {
        let _ = ::env_logger::try_init();
    }

    pub fn get_store() -> Store {
        use libimagstore::file_abstraction::InMemoryFileAbstraction;
        let backend = Arc::new(InMemoryFileAbstraction::default());
        Store::new_with_backend(PathBuf::from("/"), &None, backend).unwrap()
    }

    #[test]
    fn test_new_entry_no_links() {
        setup_logging();
        let store = get_store();
        let entry = store.create(PathBuf::from("test_new_entry_no_links")).unwrap();
        let links = entry.get_internal_links();
        assert!(links.is_ok());
        let links = links.unwrap();
        assert_eq!(links.collect::<Vec<_>>().len(), 0);
    }

    #[test]
    fn test_link_two_entries() {
        setup_logging();
        let store = get_store();
        let mut e1 = store.create(PathBuf::from("test_link_two_entries1")).unwrap();
        assert!(e1.get_internal_links().is_ok());

        let mut e2 = store.create(PathBuf::from("test_link_two_entries2")).unwrap();
        assert!(e2.get_internal_links().is_ok());

        {
            assert!(e1.add_internal_link(&mut e2).is_ok());

            let e1_links = e1.get_internal_links().unwrap().collect::<Vec<_>>();
            let e2_links = e2.get_internal_links().unwrap().collect::<Vec<_>>();

            debug!("1 has links: {:?}", e1_links);
            debug!("2 has links: {:?}", e2_links);

            assert_eq!(e1_links.len(), 1);
            assert_eq!(e2_links.len(), 1);

            assert!(e1_links.first().map(|l| l.clone().with_base(store.path().clone()).eq_store_id(e2.get_location())).unwrap_or(false));
            assert!(e2_links.first().map(|l| l.clone().with_base(store.path().clone()).eq_store_id(e1.get_location())).unwrap_or(false));
        }

        {
            assert!(e1.remove_internal_link(&mut e2).is_ok());

            debug!("{:?}", e2.to_str());
            let e2_links = e2.get_internal_links().unwrap().collect::<Vec<_>>();
            assert_eq!(e2_links.len(), 0, "Expected [], got: {:?}", e2_links);

            debug!("{:?}", e1.to_str());
            let e1_links = e1.get_internal_links().unwrap().collect::<Vec<_>>();
            assert_eq!(e1_links.len(), 0, "Expected [], got: {:?}", e1_links);

        }
    }

    #[test]
    fn test_multiple_links() {
        setup_logging();
        let store = get_store();

        let mut e1 = store.retrieve(PathBuf::from("1")).unwrap();
        let mut e2 = store.retrieve(PathBuf::from("2")).unwrap();
        let mut e3 = store.retrieve(PathBuf::from("3")).unwrap();
        let mut e4 = store.retrieve(PathBuf::from("4")).unwrap();
        let mut e5 = store.retrieve(PathBuf::from("5")).unwrap();

        assert!(e1.add_internal_link(&mut e2).is_ok());

        assert_eq!(e1.get_internal_links().unwrap().collect::<Vec<_>>().len(), 1);
        assert_eq!(e2.get_internal_links().unwrap().collect::<Vec<_>>().len(), 1);
        assert_eq!(e3.get_internal_links().unwrap().collect::<Vec<_>>().len(), 0);
        assert_eq!(e4.get_internal_links().unwrap().collect::<Vec<_>>().len(), 0);
        assert_eq!(e5.get_internal_links().unwrap().collect::<Vec<_>>().len(), 0);

        assert!(e1.add_internal_link(&mut e3).is_ok());

        assert_eq!(e1.get_internal_links().unwrap().collect::<Vec<_>>().len(), 2);
        assert_eq!(e2.get_internal_links().unwrap().collect::<Vec<_>>().len(), 1);
        assert_eq!(e3.get_internal_links().unwrap().collect::<Vec<_>>().len(), 1);
        assert_eq!(e4.get_internal_links().unwrap().collect::<Vec<_>>().len(), 0);
        assert_eq!(e5.get_internal_links().unwrap().collect::<Vec<_>>().len(), 0);

        assert!(e1.add_internal_link(&mut e4).is_ok());

        assert_eq!(e1.get_internal_links().unwrap().collect::<Vec<_>>().len(), 3);
        assert_eq!(e2.get_internal_links().unwrap().collect::<Vec<_>>().len(), 1);
        assert_eq!(e3.get_internal_links().unwrap().collect::<Vec<_>>().len(), 1);
        assert_eq!(e4.get_internal_links().unwrap().collect::<Vec<_>>().len(), 1);
        assert_eq!(e5.get_internal_links().unwrap().collect::<Vec<_>>().len(), 0);

        assert!(e1.add_internal_link(&mut e5).is_ok());

        assert_eq!(e1.get_internal_links().unwrap().collect::<Vec<_>>().len(), 4);
        assert_eq!(e2.get_internal_links().unwrap().collect::<Vec<_>>().len(), 1);
        assert_eq!(e3.get_internal_links().unwrap().collect::<Vec<_>>().len(), 1);
        assert_eq!(e4.get_internal_links().unwrap().collect::<Vec<_>>().len(), 1);
        assert_eq!(e5.get_internal_links().unwrap().collect::<Vec<_>>().len(), 1);

        assert!(e5.remove_internal_link(&mut e1).is_ok());

        assert_eq!(e1.get_internal_links().unwrap().collect::<Vec<_>>().len(), 3);
        assert_eq!(e2.get_internal_links().unwrap().collect::<Vec<_>>().len(), 1);
        assert_eq!(e3.get_internal_links().unwrap().collect::<Vec<_>>().len(), 1);
        assert_eq!(e4.get_internal_links().unwrap().collect::<Vec<_>>().len(), 1);
        assert_eq!(e5.get_internal_links().unwrap().collect::<Vec<_>>().len(), 0);

        assert!(e4.remove_internal_link(&mut e1).is_ok());

        assert_eq!(e1.get_internal_links().unwrap().collect::<Vec<_>>().len(), 2);
        assert_eq!(e2.get_internal_links().unwrap().collect::<Vec<_>>().len(), 1);
        assert_eq!(e3.get_internal_links().unwrap().collect::<Vec<_>>().len(), 1);
        assert_eq!(e4.get_internal_links().unwrap().collect::<Vec<_>>().len(), 0);
        assert_eq!(e5.get_internal_links().unwrap().collect::<Vec<_>>().len(), 0);

        assert!(e3.remove_internal_link(&mut e1).is_ok());

        assert_eq!(e1.get_internal_links().unwrap().collect::<Vec<_>>().len(), 1);
        assert_eq!(e2.get_internal_links().unwrap().collect::<Vec<_>>().len(), 1);
        assert_eq!(e3.get_internal_links().unwrap().collect::<Vec<_>>().len(), 0);
        assert_eq!(e4.get_internal_links().unwrap().collect::<Vec<_>>().len(), 0);
        assert_eq!(e5.get_internal_links().unwrap().collect::<Vec<_>>().len(), 0);

        assert!(e2.remove_internal_link(&mut e1).is_ok());

        assert_eq!(e1.get_internal_links().unwrap().collect::<Vec<_>>().len(), 0);
        assert_eq!(e2.get_internal_links().unwrap().collect::<Vec<_>>().len(), 0);
        assert_eq!(e3.get_internal_links().unwrap().collect::<Vec<_>>().len(), 0);
        assert_eq!(e4.get_internal_links().unwrap().collect::<Vec<_>>().len(), 0);
        assert_eq!(e5.get_internal_links().unwrap().collect::<Vec<_>>().len(), 0);

    }

    #[test]
    fn test_link_deleting() {
        setup_logging();
        let store = get_store();

        let mut e1 = store.retrieve(PathBuf::from("1")).unwrap();
        let mut e2 = store.retrieve(PathBuf::from("2")).unwrap();

        assert_eq!(e1.get_internal_links().unwrap().collect::<Vec<_>>().len(), 0);
        assert_eq!(e2.get_internal_links().unwrap().collect::<Vec<_>>().len(), 0);

        assert!(e1.add_internal_link(&mut e2).is_ok());

        assert_eq!(e1.get_internal_links().unwrap().collect::<Vec<_>>().len(), 1);
        assert_eq!(e2.get_internal_links().unwrap().collect::<Vec<_>>().len(), 1);

        assert!(e1.remove_internal_link(&mut e2).is_ok());

        assert_eq!(e1.get_internal_links().unwrap().collect::<Vec<_>>().len(), 0);
        assert_eq!(e2.get_internal_links().unwrap().collect::<Vec<_>>().len(), 0);
    }

    #[test]
    fn test_link_deleting_multiple_links() {
        setup_logging();
        let store = get_store();

        let mut e1 = store.retrieve(PathBuf::from("1")).unwrap();
        let mut e2 = store.retrieve(PathBuf::from("2")).unwrap();
        let mut e3 = store.retrieve(PathBuf::from("3")).unwrap();

        assert_eq!(e1.get_internal_links().unwrap().collect::<Vec<_>>().len(), 0);
        assert_eq!(e2.get_internal_links().unwrap().collect::<Vec<_>>().len(), 0);
        assert_eq!(e3.get_internal_links().unwrap().collect::<Vec<_>>().len(), 0);

        assert!(e1.add_internal_link(&mut e2).is_ok()); // 1-2
        assert!(e1.add_internal_link(&mut e3).is_ok()); // 1-2, 1-3

        assert_eq!(e1.get_internal_links().unwrap().collect::<Vec<_>>().len(), 2);
        assert_eq!(e2.get_internal_links().unwrap().collect::<Vec<_>>().len(), 1);
        assert_eq!(e3.get_internal_links().unwrap().collect::<Vec<_>>().len(), 1);

        assert!(e2.add_internal_link(&mut e3).is_ok()); // 1-2, 1-3, 2-3

        assert_eq!(e1.get_internal_links().unwrap().collect::<Vec<_>>().len(), 2);
        assert_eq!(e2.get_internal_links().unwrap().collect::<Vec<_>>().len(), 2);
        assert_eq!(e3.get_internal_links().unwrap().collect::<Vec<_>>().len(), 2);

        assert!(e1.remove_internal_link(&mut e2).is_ok()); // 1-3, 2-3

        assert_eq!(e1.get_internal_links().unwrap().collect::<Vec<_>>().len(), 1);
        assert_eq!(e2.get_internal_links().unwrap().collect::<Vec<_>>().len(), 1);
        assert_eq!(e3.get_internal_links().unwrap().collect::<Vec<_>>().len(), 2);

        assert!(e1.remove_internal_link(&mut e3).is_ok()); // 2-3

        assert_eq!(e1.get_internal_links().unwrap().collect::<Vec<_>>().len(), 0);
        assert_eq!(e2.get_internal_links().unwrap().collect::<Vec<_>>().len(), 1);
        assert_eq!(e3.get_internal_links().unwrap().collect::<Vec<_>>().len(), 1);

        assert!(e2.remove_internal_link(&mut e3).is_ok());

        assert_eq!(e1.get_internal_links().unwrap().collect::<Vec<_>>().len(), 0);
        assert_eq!(e2.get_internal_links().unwrap().collect::<Vec<_>>().len(), 0);
        assert_eq!(e3.get_internal_links().unwrap().collect::<Vec<_>>().len(), 0);
    }

    #[test]
    fn test_link_annotating() {
        setup_logging();
        let store      = get_store();
        let mut entry1 = store.create(PathBuf::from("test_link_annotating-1")).unwrap();
        let mut entry2 = store.create(PathBuf::from("test_link_annotating-2")).unwrap();

        let res = entry1.add_internal_annotated_link(&mut entry2, String::from("annotation"));
        assert!(res.is_ok());

        {
            for link in entry1.get_internal_links().unwrap() {
                match link  {
                    Link::Annotated {annotation, ..} => assert_eq!(annotation, "annotation"),
                    _ => assert!(false, "Non-annotated link found"),
                }
            }
        }

        {
            for link in entry2.get_internal_links().unwrap() {
                match link  {
                    Link::Id {..}        => {},
                    Link::Annotated {..} => assert!(false, "Annotated link found"),
                }
            }
        }
    }

}