package grpcplugin

import (
	"context"
	"errors"
	"fmt"
	"io"

	"github.com/grafana/grafana-plugin-sdk-go/backend"
	"github.com/grafana/grafana-plugin-sdk-go/backend/grpcplugin"
	"github.com/grafana/grafana-plugin-sdk-go/genproto/pluginv2"
	"github.com/grafana/grafana/pkg/infra/log"
	"github.com/grafana/grafana/pkg/plugins/backendplugin"
	"github.com/grafana/grafana/pkg/plugins/backendplugin/pluginextensionv2"
	"github.com/grafana/grafana/pkg/util/errutil"
	"github.com/hashicorp/go-plugin"
	"google.golang.org/grpc/codes"
	"google.golang.org/grpc/status"
)

type ClientV2 struct {
	grpcplugin.DiagnosticsClient
	grpcplugin.ResourceClient
	grpcplugin.DataClient
	grpcplugin.StreamClient
	pluginextensionv2.RendererPlugin
}

func newClientV2(descriptor PluginDescriptor, logger log.Logger, rpcClient plugin.ClientProtocol) (pluginClient, error) {
	rawDiagnostics, err := rpcClient.Dispense("diagnostics")
	if err != nil {
		return nil, err
	}

	rawResource, err := rpcClient.Dispense("resource")
	if err != nil {
		return nil, err
	}

	rawData, err := rpcClient.Dispense("data")
	if err != nil {
		return nil, err
	}

	rawStream, err := rpcClient.Dispense("stream")
	if err != nil {
		return nil, err
	}

	rawRenderer, err := rpcClient.Dispense("renderer")
	if err != nil {
		return nil, err
	}

	c := ClientV2{}
	if rawDiagnostics != nil {
		if diagnosticsClient, ok := rawDiagnostics.(grpcplugin.DiagnosticsClient); ok {
			c.DiagnosticsClient = diagnosticsClient
		}
	}

	if rawResource != nil {
		if resourceClient, ok := rawResource.(grpcplugin.ResourceClient); ok {
			c.ResourceClient = resourceClient
		}
	}

	if rawData != nil {
		if dataClient, ok := rawData.(grpcplugin.DataClient); ok {
			c.DataClient = dataClient
		}
	}

	if rawStream != nil {
		if streamClient, ok := rawStream.(grpcplugin.StreamClient); ok {
			c.StreamClient = streamClient
		}
	}

	if rawRenderer != nil {
		if rendererPlugin, ok := rawRenderer.(pluginextensionv2.RendererPlugin); ok {
			c.RendererPlugin = rendererPlugin
		}
	}

	if descriptor.startRendererFn != nil {
		if err := descriptor.startRendererFn(descriptor.pluginID, c.RendererPlugin, logger); err != nil {
			return nil, err
		}
	}

	return &c, nil
}

func (c *ClientV2) CollectMetrics(ctx context.Context, req *backend.CollectMetricsRequest) (*backend.CollectMetricsResult, error) {
	if c.DiagnosticsClient == nil {
		return &backend.CollectMetricsResult{}, nil
	}

	protoResp, err := c.DiagnosticsClient.CollectMetrics(ctx, backend.ToProto().CollectMetricsRequest(req))
	if err != nil {
		if status.Code(err) == codes.Unimplemented {
			return &backend.CollectMetricsResult{}, nil
		}

		return nil, err
	}

	return backend.FromProto().CollectMetricsResponse(protoResp), nil
}

func (c *ClientV2) CheckHealth(ctx context.Context, req *backend.CheckHealthRequest) (*backend.CheckHealthResult, error) {
	if c.DiagnosticsClient == nil {
		return nil, backendplugin.ErrMethodNotImplemented
	}

	protoContext := backend.ToProto().PluginContext(req.PluginContext)
	protoResp, err := c.DiagnosticsClient.CheckHealth(ctx, &pluginv2.CheckHealthRequest{PluginContext: protoContext})

	if err != nil {
		if status.Code(err) == codes.Unimplemented {
			return &backend.CheckHealthResult{
				Status:  backend.HealthStatusUnknown,
				Message: "Health check not implemented",
			}, nil
		}
		return nil, err
	}

	return backend.FromProto().CheckHealthResponse(protoResp), nil
}

func (c *ClientV2) QueryData(ctx context.Context, req *backend.QueryDataRequest) (*backend.QueryDataResponse, error) {
	if c.DataClient == nil {
		return nil, backendplugin.ErrMethodNotImplemented
	}

	protoReq := backend.ToProto().QueryDataRequest(req)
	protoResp, err := c.DataClient.QueryData(ctx, protoReq)

	if err != nil {
		if status.Code(err) == codes.Unimplemented {
			return nil, backendplugin.ErrMethodNotImplemented
		}

		return nil, errutil.Wrap("Failed to query data", err)
	}

	return backend.FromProto().QueryDataResponse(protoResp)
}

func (c *ClientV2) CallResource(ctx context.Context, req *backend.CallResourceRequest, sender backend.CallResourceResponseSender) error {
	if c.ResourceClient == nil {
		return backendplugin.ErrMethodNotImplemented
	}

	protoReq := backend.ToProto().CallResourceRequest(req)
	protoStream, err := c.ResourceClient.CallResource(ctx, protoReq)
	if err != nil {
		if status.Code(err) == codes.Unimplemented {
			return backendplugin.ErrMethodNotImplemented
		}

		return errutil.Wrap("Failed to call resource", err)
	}

	for {
		protoResp, err := protoStream.Recv()
		if err != nil {
			if status.Code(err) == codes.Unimplemented {
				return backendplugin.ErrMethodNotImplemented
			}

			if errors.Is(err, io.EOF) {
				return nil
			}

			return errutil.Wrap("failed to receive call resource response", err)
		}

		if err := sender.Send(backend.FromProto().CallResourceResponse(protoResp)); err != nil {
			return err
		}
	}
}

func (c *ClientV2) SubscribeStream(ctx context.Context, req *backend.SubscribeStreamRequest) (*backend.SubscribeStreamResponse, error) {
	if c.StreamClient == nil {
		return nil, backendplugin.ErrMethodNotImplemented
	}
	protoResp, err := c.StreamClient.SubscribeStream(ctx, backend.ToProto().SubscribeStreamRequest(req))
	if err != nil {
		return nil, err
	}
	return backend.FromProto().SubscribeStreamResponse(protoResp), nil
}

func (c *ClientV2) PublishStream(ctx context.Context, req *backend.PublishStreamRequest) (*backend.PublishStreamResponse, error) {
	if c.StreamClient == nil {
		return nil, backendplugin.ErrMethodNotImplemented
	}
	protoResp, err := c.StreamClient.PublishStream(ctx, backend.ToProto().PublishStreamRequest(req))
	if err != nil {
		return nil, err
	}
	return backend.FromProto().PublishStreamResponse(protoResp), nil
}

func (c *ClientV2) RunStream(ctx context.Context, req *backend.RunStreamRequest, sender *backend.StreamSender) error {
	if c.StreamClient == nil {
		return backendplugin.ErrMethodNotImplemented
	}

	protoReq := backend.ToProto().RunStreamRequest(req)
	protoStream, err := c.StreamClient.RunStream(ctx, protoReq)
	if err != nil {
		if status.Code(err) == codes.Unimplemented {
			return backendplugin.ErrMethodNotImplemented
		}
		return errutil.Wrap("Failed to call resource", err)
	}

	for {
		p, err := protoStream.Recv()
		if err != nil {
			if status.Code(err) == codes.Unimplemented {
				return backendplugin.ErrMethodNotImplemented
			}
			if errors.Is(err, io.EOF) {
				return nil
			}
			return fmt.Errorf("error running stream: %w", err)
		}
		// From GRPC connection we receive already prepared JSON.
		err = sender.SendJSON(p.Data)
		if err != nil {
			return err
		}
	}
}