package main

import (
	"context"
	"fmt"
	"sync"

	"github.com/hashicorp/hcl/v2/hclsimple"
	configv1 "github.com/spiffe/spire-plugin-sdk/proto/spire/service/common/config/v1"
	workloadattestorv1 "github.com/spiffe/spire-plugin-sdk/proto/spire/plugin/agent/workloadattestor/v1"
	"github.com/spiffe/spire-plugin-sdk/pluginmain"
	"google.golang.org/grpc/codes"
	"google.golang.org/grpc/status"
)

type Plugin struct {
	workloadattestorv1.UnimplementedWorkloadAttestorServer
	configv1.UnimplementedConfigServer

	mu       sync.RWMutex
	attestor *GsapAttestor
}

func (p *Plugin) Attest(ctx context.Context, req *workloadattestorv1.AttestRequest) (*workloadattestorv1.AttestResponse, error) {
	p.mu.RLock()
	a := p.attestor
	p.mu.RUnlock()

	if a == nil {
		return nil, status.Error(codes.FailedPrecondition, "plugin not configured")
	}

	selectors, err := a.Attest(ctx, req.Pid)
	if err != nil {
		return nil, status.Errorf(codes.Internal, "attestation failed: %v", err)
	}

	return &workloadattestorv1.AttestResponse{
		SelectorValues: selectors,
	}, nil
}

func decodeConfig(data string) (GsapAttestorConfig, error) {
	var cfg GsapAttestorConfig
	jsonErr := hclsimple.Decode("plugin.json", []byte(data), nil, &cfg)
	if jsonErr == nil {
		return cfg, nil
	}
	hclErr := hclsimple.Decode("plugin.hcl", []byte(data), nil, &cfg)
	if hclErr == nil {
		return cfg, nil
	}
	return cfg, fmt.Errorf("json: %v; hcl: %v; raw input: %q", jsonErr, hclErr, data)
}

func (p *Plugin) Configure(_ context.Context, req *configv1.ConfigureRequest) (*configv1.ConfigureResponse, error) {
	cfg, err := decodeConfig(req.HclConfiguration)
	if err != nil {
		return nil, status.Errorf(codes.InvalidArgument, "failed to decode configuration: %v", err)
	}

	a := &GsapAttestor{}
	if err := a.Configure(cfg); err != nil {
		return nil, status.Errorf(codes.InvalidArgument, "invalid configuration: %v", err)
	}

	p.mu.Lock()
	p.attestor = a
	p.mu.Unlock()

	return &configv1.ConfigureResponse{}, nil
}

func (p *Plugin) Validate(_ context.Context, req *configv1.ValidateRequest) (*configv1.ValidateResponse, error) {
	if _, err := decodeConfig(req.HclConfiguration); err != nil {
		return nil, status.Errorf(codes.InvalidArgument, "failed to decode configuration: %v", err)
	}
	return &configv1.ValidateResponse{}, nil
}

func main() {
	p := &Plugin{}
	pluginmain.Serve(
		workloadattestorv1.WorkloadAttestorPluginServer(p),
		configv1.ConfigServiceServer(p),
	)
}