package agentv1

import (
	"context"

	"google.golang.org/grpc"
)

// ServiceName is the fully-qualified gRPC service name. It MUST match the value
// the mTLS interceptor whitelists for Enroll (server/internal/mtls/identity.go).
const ServiceName = "pangolin.agent.v1.AgentService"

// Fully-qualified method names.
const (
	MethodEnroll      = "/" + ServiceName + "/Enroll"
	MethodRegister    = "/" + ServiceName + "/Register"
	MethodHeartbeat   = "/" + ServiceName + "/Heartbeat"
	MethodSubscribe   = "/" + ServiceName + "/Subscribe"
	MethodAck         = "/" + ServiceName + "/Ack"
	MethodReportUsage = "/" + ServiceName + "/ReportUsage"
)

// withCodec forces the JSON content-subtype on every call so the contract does
// not depend on the caller remembering to set dial-level call options.
func withCodec(opts []grpc.CallOption) []grpc.CallOption {
	return append([]grpc.CallOption{grpc.CallContentSubtype(CodecName)}, opts...)
}

// ─── server interface ──────────────────────────────────────────────────────────

// AgentServiceServer is implemented by the control plane.
type AgentServiceServer interface {
	Enroll(context.Context, *EnrollRequest) (*EnrollResponse, error)
	Register(context.Context, *RegisterRequest) (*ConfigSnapshot, error)
	Heartbeat(context.Context, *HeartbeatRequest) (*HeartbeatResponse, error)
	Subscribe(*SubscribeRequest, AgentService_SubscribeServer) error
	Ack(context.Context, *AckRequest) (*AckResponse, error)
	ReportUsage(context.Context, *UsageReport) (*UsageAck, error)
}

// AgentService_SubscribeServer is the server side of the Command stream.
type AgentService_SubscribeServer interface {
	Send(*Command) error
	grpc.ServerStream
}

type subscribeServer struct{ grpc.ServerStream }

func (s *subscribeServer) Send(m *Command) error { return s.ServerStream.SendMsg(m) }

// RegisterAgentServiceServer wires srv into a gRPC server (or any ServiceRegistrar).
func RegisterAgentServiceServer(s grpc.ServiceRegistrar, srv AgentServiceServer) {
	s.RegisterService(&serviceDesc, srv)
}

func handlerEnroll(srv any, ctx context.Context, dec func(any) error, interceptor grpc.UnaryServerInterceptor) (any, error) {
	in := new(EnrollRequest)
	if err := dec(in); err != nil {
		return nil, err
	}
	if interceptor == nil {
		return srv.(AgentServiceServer).Enroll(ctx, in)
	}
	info := &grpc.UnaryServerInfo{Server: srv, FullMethod: MethodEnroll}
	return interceptor(ctx, in, info, func(ctx context.Context, req any) (any, error) {
		return srv.(AgentServiceServer).Enroll(ctx, req.(*EnrollRequest))
	})
}

func handlerRegister(srv any, ctx context.Context, dec func(any) error, interceptor grpc.UnaryServerInterceptor) (any, error) {
	in := new(RegisterRequest)
	if err := dec(in); err != nil {
		return nil, err
	}
	if interceptor == nil {
		return srv.(AgentServiceServer).Register(ctx, in)
	}
	info := &grpc.UnaryServerInfo{Server: srv, FullMethod: MethodRegister}
	return interceptor(ctx, in, info, func(ctx context.Context, req any) (any, error) {
		return srv.(AgentServiceServer).Register(ctx, req.(*RegisterRequest))
	})
}

func handlerHeartbeat(srv any, ctx context.Context, dec func(any) error, interceptor grpc.UnaryServerInterceptor) (any, error) {
	in := new(HeartbeatRequest)
	if err := dec(in); err != nil {
		return nil, err
	}
	if interceptor == nil {
		return srv.(AgentServiceServer).Heartbeat(ctx, in)
	}
	info := &grpc.UnaryServerInfo{Server: srv, FullMethod: MethodHeartbeat}
	return interceptor(ctx, in, info, func(ctx context.Context, req any) (any, error) {
		return srv.(AgentServiceServer).Heartbeat(ctx, req.(*HeartbeatRequest))
	})
}

func handlerAck(srv any, ctx context.Context, dec func(any) error, interceptor grpc.UnaryServerInterceptor) (any, error) {
	in := new(AckRequest)
	if err := dec(in); err != nil {
		return nil, err
	}
	if interceptor == nil {
		return srv.(AgentServiceServer).Ack(ctx, in)
	}
	info := &grpc.UnaryServerInfo{Server: srv, FullMethod: MethodAck}
	return interceptor(ctx, in, info, func(ctx context.Context, req any) (any, error) {
		return srv.(AgentServiceServer).Ack(ctx, req.(*AckRequest))
	})
}

func handlerReportUsage(srv any, ctx context.Context, dec func(any) error, interceptor grpc.UnaryServerInterceptor) (any, error) {
	in := new(UsageReport)
	if err := dec(in); err != nil {
		return nil, err
	}
	if interceptor == nil {
		return srv.(AgentServiceServer).ReportUsage(ctx, in)
	}
	info := &grpc.UnaryServerInfo{Server: srv, FullMethod: MethodReportUsage}
	return interceptor(ctx, in, info, func(ctx context.Context, req any) (any, error) {
		return srv.(AgentServiceServer).ReportUsage(ctx, req.(*UsageReport))
	})
}

func handlerSubscribe(srv any, stream grpc.ServerStream) error {
	m := new(SubscribeRequest)
	if err := stream.RecvMsg(m); err != nil {
		return err
	}
	return srv.(AgentServiceServer).Subscribe(m, &subscribeServer{stream})
}

var serviceDesc = grpc.ServiceDesc{
	ServiceName: ServiceName,
	HandlerType: (*AgentServiceServer)(nil),
	Methods: []grpc.MethodDesc{
		{MethodName: "Enroll", Handler: handlerEnroll},
		{MethodName: "Register", Handler: handlerRegister},
		{MethodName: "Heartbeat", Handler: handlerHeartbeat},
		{MethodName: "Ack", Handler: handlerAck},
		{MethodName: "ReportUsage", Handler: handlerReportUsage},
	},
	Streams: []grpc.StreamDesc{
		{StreamName: "Subscribe", Handler: handlerSubscribe, ServerStreams: true},
	},
	Metadata: "proto/agent/v1/agent.proto",
}

// ─── client ─────────────────────────────────────────────────────────────────────

// AgentServiceClient is consumed by the node agent.
type AgentServiceClient interface {
	Enroll(ctx context.Context, in *EnrollRequest, opts ...grpc.CallOption) (*EnrollResponse, error)
	Register(ctx context.Context, in *RegisterRequest, opts ...grpc.CallOption) (*ConfigSnapshot, error)
	Heartbeat(ctx context.Context, in *HeartbeatRequest, opts ...grpc.CallOption) (*HeartbeatResponse, error)
	Subscribe(ctx context.Context, in *SubscribeRequest, opts ...grpc.CallOption) (AgentService_SubscribeClient, error)
	Ack(ctx context.Context, in *AckRequest, opts ...grpc.CallOption) (*AckResponse, error)
	ReportUsage(ctx context.Context, in *UsageReport, opts ...grpc.CallOption) (*UsageAck, error)
}

// AgentService_SubscribeClient is the client side of the Command stream.
type AgentService_SubscribeClient interface {
	Recv() (*Command, error)
	grpc.ClientStream
}

type subscribeClient struct{ grpc.ClientStream }

func (c *subscribeClient) Recv() (*Command, error) {
	m := new(Command)
	if err := c.ClientStream.RecvMsg(m); err != nil {
		return nil, err
	}
	return m, nil
}

type agentServiceClient struct{ cc grpc.ClientConnInterface }

// NewAgentServiceClient returns a client bound to cc. All calls use the JSON codec.
func NewAgentServiceClient(cc grpc.ClientConnInterface) AgentServiceClient {
	return &agentServiceClient{cc}
}

func (c *agentServiceClient) Enroll(ctx context.Context, in *EnrollRequest, opts ...grpc.CallOption) (*EnrollResponse, error) {
	out := new(EnrollResponse)
	if err := c.cc.Invoke(ctx, MethodEnroll, in, out, withCodec(opts)...); err != nil {
		return nil, err
	}
	return out, nil
}

func (c *agentServiceClient) Register(ctx context.Context, in *RegisterRequest, opts ...grpc.CallOption) (*ConfigSnapshot, error) {
	out := new(ConfigSnapshot)
	if err := c.cc.Invoke(ctx, MethodRegister, in, out, withCodec(opts)...); err != nil {
		return nil, err
	}
	return out, nil
}

func (c *agentServiceClient) Heartbeat(ctx context.Context, in *HeartbeatRequest, opts ...grpc.CallOption) (*HeartbeatResponse, error) {
	out := new(HeartbeatResponse)
	if err := c.cc.Invoke(ctx, MethodHeartbeat, in, out, withCodec(opts)...); err != nil {
		return nil, err
	}
	return out, nil
}

func (c *agentServiceClient) Ack(ctx context.Context, in *AckRequest, opts ...grpc.CallOption) (*AckResponse, error) {
	out := new(AckResponse)
	if err := c.cc.Invoke(ctx, MethodAck, in, out, withCodec(opts)...); err != nil {
		return nil, err
	}
	return out, nil
}

func (c *agentServiceClient) ReportUsage(ctx context.Context, in *UsageReport, opts ...grpc.CallOption) (*UsageAck, error) {
	out := new(UsageAck)
	if err := c.cc.Invoke(ctx, MethodReportUsage, in, out, withCodec(opts)...); err != nil {
		return nil, err
	}
	return out, nil
}

func (c *agentServiceClient) Subscribe(ctx context.Context, in *SubscribeRequest, opts ...grpc.CallOption) (AgentService_SubscribeClient, error) {
	stream, err := c.cc.NewStream(ctx, &serviceDesc.Streams[0], MethodSubscribe, withCodec(opts)...)
	if err != nil {
		return nil, err
	}
	x := &subscribeClient{stream}
	if err := x.ClientStream.SendMsg(in); err != nil {
		return nil, err
	}
	if err := x.ClientStream.CloseSend(); err != nil {
		return nil, err
	}
	return x, nil
}
