/// If `Yes`, don't really make changes but do as much as possible to get an idea of what would be done.
#[derive(Debug, Copy, Clone, PartialEq, Eq)]
#[cfg(any(feature = "blocking-network-client", feature = "async-network-client"))]
pub(crate) enum DryRun {
    /// Enable dry-run mode and don't actually change the underlying repository in any way.
    Yes,
    /// Run the operation like normal, making changes to the underlying repository.
    No,
}

/// How to deal with refs when cloning or fetching.
#[derive(Debug, Copy, Clone, PartialEq, Eq)]
#[cfg(any(feature = "blocking-network-client", feature = "async-network-client"))]
pub(crate) enum WritePackedRefs {
    /// Normal operation, i.e. don't use packed-refs at all for writing.
    Never,
    /// Put ref updates straight into the `packed-refs` file, without creating loose refs first or dealing with them in any way.
    Only,
}

/// Describe how to handle tags when fetching
#[derive(Debug, Copy, Clone, PartialEq, Eq)]
pub enum Tags {
    /// Fetch all tags from the remote, even if these are not reachable from objects referred to by our refspecs.
    All,
    /// Fetch only the tags that point to the objects being sent.
    /// That way, annotated tags that point to an object we receive are automatically transmitted and their refs are created.
    /// The same goes for lightweight tags.
    Included,
    /// Do not fetch any tags.
    None,
}

impl Default for Tags {
    fn default() -> Self {
        Tags::Included
    }
}

impl Tags {
    /// Obtain a refspec that determines whether or not to fetch all tags, depending on this variant.
    ///
    /// The returned refspec is the default refspec for tags, but won't overwrite local tags ever.
    pub fn to_refspec(&self) -> Option<git_refspec::RefSpecRef<'static>> {
        match self {
            Tags::All | Tags::Included => Some(
                git_refspec::parse("refs/tags/*:refs/tags/*".into(), git_refspec::parse::Operation::Fetch)
                    .expect("valid"),
            ),
            Tags::None => None,
        }
    }
}

/// Information about the relationship between our refspecs, and remote references with their local counterparts.
#[derive(Default, Debug, Clone)]
#[cfg(any(feature = "blocking-network-client", feature = "async-network-client"))]
pub struct RefMap {
    /// A mapping between a remote reference and a local tracking branch.
    pub mappings: Vec<Mapping>,
    /// Refspecs which have been added implicitly due to settings of the `remote`, possibly pre-initialized from
    /// [`extra_refspecs` in RefMap options][crate::remote::ref_map::Options::extra_refspecs].
    ///
    /// They are never persisted nor are they typically presented to the user.
    pub extra_refspecs: Vec<git_refspec::RefSpec>,
    /// Information about the fixes applied to the `mapping` due to validation and sanitization.
    pub fixes: Vec<git_refspec::match_group::validate::Fix>,
    /// All refs advertised by the remote.
    pub remote_refs: Vec<git_protocol::handshake::Ref>,
    /// Additional information provided by the server as part of the handshake.
    ///
    /// Note that the `refs` field is always `None` as the refs are placed in `remote_refs`.
    pub handshake: git_protocol::handshake::Outcome,
    /// The kind of hash used for all data sent by the server, if understood by this client implementation.
    ///
    /// It was extracted from the `handshake` as advertised by the server.
    pub object_hash: git_hash::Kind,
}

/// Either an object id that the remote has or the matched remote ref itself.
#[derive(Debug, Clone)]
#[cfg(any(feature = "blocking-network-client", feature = "async-network-client"))]
pub enum Source {
    /// An object id, as the matched ref-spec was an object id itself.
    ObjectId(git_hash::ObjectId),
    /// The remote reference that matched the ref-specs name.
    Ref(git_protocol::handshake::Ref),
}

#[cfg(any(feature = "blocking-network-client", feature = "async-network-client"))]
impl Source {
    /// Return either the direct object id we refer to or the direct target that a reference refers to.
    /// The latter may be a direct or a symbolic reference, and we degenerate this to the peeled object id.
    /// If unborn, `None` is returned.
    pub fn as_id(&self) -> Option<&git_hash::oid> {
        match self {
            Source::ObjectId(id) => Some(id),
            Source::Ref(r) => r.unpack().1,
        }
    }

    /// Return ourselves as the full name of the reference we represent, or `None` if this source isn't a reference but an object.
    pub fn as_name(&self) -> Option<&crate::bstr::BStr> {
        match self {
            Source::ObjectId(_) => None,
            Source::Ref(r) => match r {
                git_protocol::handshake::Ref::Unborn { full_ref_name, .. }
                | git_protocol::handshake::Ref::Symbolic { full_ref_name, .. }
                | git_protocol::handshake::Ref::Direct { full_ref_name, .. }
                | git_protocol::handshake::Ref::Peeled { full_ref_name, .. } => Some(full_ref_name.as_ref()),
            },
        }
    }
}

/// An index into various lists of refspecs that have been used in a [Mapping] of remote references to local ones.
#[cfg(any(feature = "blocking-network-client", feature = "async-network-client"))]
#[derive(Debug, Copy, Clone, Eq, PartialEq, Hash, Ord, PartialOrd)]
pub enum SpecIndex {
    /// An index into the _refspecs of the remote_ that triggered a fetch operation.
    /// These refspecs are explicit and visible to the user.
    ExplicitInRemote(usize),
    /// An index into the list of [extra refspecs][crate::remote::fetch::RefMap::extra_refspecs] that are implicit
    /// to a particular fetch operation.
    Implicit(usize),
}

#[cfg(any(feature = "blocking-network-client", feature = "async-network-client"))]
impl SpecIndex {
    /// Depending on our index variant, get the index either from `refspecs` or from `extra_refspecs` for `Implicit` variants.
    pub fn get<'a>(
        self,
        refspecs: &'a [git_refspec::RefSpec],
        extra_refspecs: &'a [git_refspec::RefSpec],
    ) -> Option<&'a git_refspec::RefSpec> {
        match self {
            SpecIndex::ExplicitInRemote(idx) => refspecs.get(idx),
            SpecIndex::Implicit(idx) => extra_refspecs.get(idx),
        }
    }

    /// If this is an `Implicit` variant, return its index.
    pub fn implicit_index(self) -> Option<usize> {
        match self {
            SpecIndex::Implicit(idx) => Some(idx),
            SpecIndex::ExplicitInRemote(_) => None,
        }
    }
}

/// A mapping between a single remote reference and its advertised objects to a local destination which may or may not exist.
#[derive(Debug, Clone)]
#[cfg(any(feature = "blocking-network-client", feature = "async-network-client"))]
pub struct Mapping {
    /// The reference on the remote side, along with information about the objects they point to as advertised by the server.
    pub remote: Source,
    /// The local tracking reference to update after fetching the object visible via `remote`.
    pub local: Option<crate::bstr::BString>,
    /// The index into the fetch ref-specs used to produce the mapping, allowing it to be recovered.   
    pub spec_index: SpecIndex,
}

#[cfg(any(feature = "blocking-network-client", feature = "async-network-client"))]
pub use super::connection::fetch::{
    negotiate, prepare, refs, Error, Outcome, Prepare, ProgressId, RefLogMessage, Status,
};