// Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
// Copyright by contributors to this project.
// SPDX-License-Identifier: (Apache-2.0 OR MIT)

use alloc::vec;
use alloc::vec::Vec;
use mls_rs_codec::{MlsDecode, MlsEncode, MlsSize};

use crate::{
    crypto::CipherSuite,
    extension::{ExtensionList, ExtensionType},
    identity::{CredentialType, SigningIdentity},
    protocol_version::ProtocolVersion,
};

use super::ProposalType;

#[derive(Clone, PartialEq, Eq, Debug, MlsSize, MlsEncode, MlsDecode)]
#[cfg_attr(feature = "arbitrary", derive(arbitrary::Arbitrary))]
#[cfg_attr(
    all(feature = "ffi", not(test)),
    safer_ffi_gen::ffi_type(clone, opaque)
)]
///  Capabilities of a MLS client
pub struct Capabilities {
    pub protocol_versions: Vec<ProtocolVersion>,
    pub cipher_suites: Vec<CipherSuite>,
    pub extensions: Vec<ExtensionType>,
    pub proposals: Vec<ProposalType>,
    pub credentials: Vec<CredentialType>,
}

#[cfg_attr(all(feature = "ffi", not(test)), safer_ffi_gen::safer_ffi_gen)]
impl Capabilities {
    /// Supported protocol versions
    #[cfg(feature = "ffi")]
    pub fn protocol_versions(&self) -> &[ProtocolVersion] {
        &self.protocol_versions
    }

    /// Supported ciphersuites
    #[cfg(feature = "ffi")]
    pub fn cipher_suites(&self) -> &[CipherSuite] {
        &self.cipher_suites
    }

    /// Supported extensions
    #[cfg(feature = "ffi")]
    pub fn extensions(&self) -> &[ExtensionType] {
        &self.extensions
    }

    /// Supported proposals
    #[cfg(feature = "ffi")]
    pub fn proposals(&self) -> &[ProposalType] {
        &self.proposals
    }

    /// Supported credentials
    #[cfg(feature = "ffi")]
    pub fn credentials(&self) -> &[CredentialType] {
        &self.credentials
    }
}

impl Default for Capabilities {
    fn default() -> Self {
        use crate::identity::BasicCredential;

        Self {
            protocol_versions: vec![ProtocolVersion::MLS_10],
            cipher_suites: CipherSuite::all().collect(),
            extensions: Default::default(),
            proposals: Default::default(),
            credentials: vec![BasicCredential::credential_type()],
        }
    }
}

/// A member of a MLS group.
#[cfg_attr(
    all(feature = "ffi", not(test)),
    safer_ffi_gen::ffi_type(clone, opaque)
)]
#[derive(Debug, Clone, PartialEq, Eq)]
#[non_exhaustive]
pub struct Member {
    /// The index of this member within a group.
    ///
    /// This value is consistent for all clients and will not change as the
    /// group evolves.
    pub index: u32,
    /// Current identity public key and credential of this member.
    pub signing_identity: SigningIdentity,
    /// Current client [Capabilities] of this member.
    pub capabilities: Capabilities,
    /// Current leaf node extensions in use by this member.
    pub extensions: ExtensionList,
}

#[cfg_attr(all(feature = "ffi", not(test)), safer_ffi_gen::safer_ffi_gen)]
impl Member {
    pub fn new(
        index: u32,
        signing_identity: SigningIdentity,
        capabilities: Capabilities,
        extensions: ExtensionList,
    ) -> Self {
        Self {
            index,
            signing_identity,
            capabilities,
            extensions,
        }
    }

    /// The index of this member within a group.
    ///
    /// This value is consistent for all clients and will not change as the
    /// group evolves.
    #[cfg(feature = "ffi")]
    pub fn index(&self) -> u32 {
        self.index
    }

    /// Current identity public key and credential of this member.
    #[cfg(feature = "ffi")]
    pub fn signing_identity(&self) -> &SigningIdentity {
        &self.signing_identity
    }

    /// Current client [Capabilities] of this member.
    #[cfg(feature = "ffi")]
    pub fn capabilities(&self) -> &Capabilities {
        &self.capabilities
    }

    /// Current leaf node extensions in use by this member.
    #[cfg(feature = "ffi")]
    pub fn extensions(&self) -> &ExtensionList {
        &self.extensions
    }
}

#[derive(Clone, Debug, PartialEq)]
#[non_exhaustive]
#[cfg_attr(
    all(feature = "ffi", not(test)),
    safer_ffi_gen::ffi_type(clone, opaque)
)]
/// Update of a member due to a commit.
pub struct MemberUpdate {
    pub prior: Member,
    pub new: Member,
}

#[cfg_attr(all(feature = "ffi", not(test)), safer_ffi_gen::safer_ffi_gen)]
impl MemberUpdate {
    /// Create a new member update.
    pub fn new(prior: Member, new: Member) -> MemberUpdate {
        MemberUpdate { prior, new }
    }

    /// The index that was updated.
    pub fn index(&self) -> u32 {
        self.new.index
    }

    /// Member state before the update.
    #[cfg(feature = "ffi")]
    pub fn before_update(&self) -> &Member {
        &self.prior
    }

    /// Member state after the update.
    #[cfg(feature = "ffi")]
    pub fn after_update(&self) -> &Member {
        &self.new
    }
}

/// A set of roster updates due to a commit.
#[derive(Clone, Debug, PartialEq)]
#[non_exhaustive]
pub struct RosterUpdate {
    pub(crate) added: Vec<Member>,
    pub(crate) removed: Vec<Member>,
    pub(crate) updated: Vec<MemberUpdate>,
}

impl RosterUpdate {
    /// Create a new roster update.
    pub fn new(
        mut added: Vec<Member>,
        mut removed: Vec<Member>,
        mut updated: Vec<MemberUpdate>,
    ) -> RosterUpdate {
        added.sort_by_key(|m| m.index);
        removed.sort_by_key(|m| m.index);
        updated.sort_by_key(|u| u.index());

        RosterUpdate {
            added,
            removed,
            updated,
        }
    }
    /// Members added via this update.
    pub fn added(&self) -> &[Member] {
        &self.added
    }

    /// Members removed via this update.
    pub fn removed(&self) -> &[Member] {
        &self.removed
    }

    /// Members updated via this update.
    pub fn updated(&self) -> &[MemberUpdate] {
        &self.updated
    }
}