package network

import (
	"context"
	"fmt"
	"io"
	"isle/bootstrap"
	"isle/daemon/children"
	"isle/daemon/daecommon"
	"isle/nebula"
	"isle/toolkit"
	"os"
	"path/filepath"
	"sync"
	"sync/atomic"
	"testing"

	"dev.mediocregopher.com/mediocre-go-lib.git/mlog"
	"gopkg.in/yaml.v3"
)

// Utilities related to running network integration tests

var (
	getEnvBinDirPath = sync.OnceValue(func() string {
		appDirPath := os.Getenv("APPDIR")
		if appDirPath == "" {
			panic("APPDIR not set")
		}
		return filepath.Join(appDirPath, "bin")
	})

	ipNetCounter          uint64 = 0
	publicAddrPortCounter uint64 = 1024
	tunDeviceCounter      uint64 = 0
)

func newIPNet() nebula.IPNet {
	var (
		ipNet    nebula.IPNet
		ipNetStr = fmt.Sprintf(
			"172.16.%d.0/24", atomic.AddUint64(&ipNetCounter, 1),
		)
	)

	if err := ipNet.UnmarshalText([]byte(ipNetStr)); err != nil {
		panic(fmt.Sprintf("parsing IPNet from %q: %v", ipNetStr, err))
	}

	return ipNet
}

func newPublicAddr() string {
	return fmt.Sprintf(
		"127.0.0.200:%d", atomic.AddUint64(&publicAddrPortCounter, 1),
	)
}

func newTunDevice() string {
	return fmt.Sprintf("isle-test-%d", atomic.AddUint64(&tunDeviceCounter, 1))
}

func mustParseNetworkConfigf(str string, args ...any) daecommon.NetworkConfig {
	str = fmt.Sprintf(str, args...)

	var networkConfig daecommon.NetworkConfig
	if err := yaml.Unmarshal([]byte(str), &networkConfig); err != nil {
		panic(fmt.Sprintf("parsing network config: %v", err))
	}
	return networkConfig
}

type integrationHarness struct {
	ctx        context.Context
	logger     *mlog.Logger
	rootDir    toolkit.Dir
	dirCounter uint64
}

func newIntegrationHarness(t *testing.T) *integrationHarness {
	t.Parallel()
	toolkit.MarkIntegrationTest(t)

	rootDir, err := os.MkdirTemp("", "isle-network-it-test.*")
	if err != nil {
		t.Fatalf("creating root temp dir: %v", err)
	}
	t.Logf("Temporary test directory: %q", rootDir)

	t.Cleanup(func() {
		if t.Failed() {
			t.Logf("Temp directory for failed test not deleted: %q", rootDir)
			return
		}

		t.Logf("Deleting temp directory %q", rootDir)
		if err := os.RemoveAll(rootDir); err != nil {
			t.Errorf("failed to remove %q: %v", rootDir, err)
		}
	})

	return &integrationHarness{
		ctx:     context.Background(),
		logger:  mlog.NewLogger(nil),
		rootDir: toolkit.Dir{Path: rootDir},
	}
}

func (h *integrationHarness) mkDir(t *testing.T, name string) toolkit.Dir {
	fullName := fmt.Sprintf("%s-%d", name, atomic.AddUint64(&h.dirCounter, 1))

	t.Logf("Creating directory %q", fullName)
	d, err := h.rootDir.MkChildDir(fullName, false)
	if err != nil {
		t.Fatalf("creating %q: %v", fullName, err)
	}

	return d
}

type createNetworkOpts struct {
	creationParams bootstrap.CreationParams
	manualShutdown bool
}

func (o *createNetworkOpts) withDefaults() *createNetworkOpts {
	if o == nil {
		o = new(createNetworkOpts)
	}

	if o.creationParams == (bootstrap.CreationParams{}) {
		o.creationParams = bootstrap.NewCreationParams("test", "test.localnet")
	}

	return o
}

type integrationHarnessNetwork struct {
	Network

	creationParams       bootstrap.CreationParams
	networkConfig        daecommon.NetworkConfig
	stateDir, runtimeDir toolkit.Dir
	opts                 *Opts
}

func (h *integrationHarness) createNetwork(
	t *testing.T,
	hostNameStr string,
	opts *createNetworkOpts,
) integrationHarnessNetwork {
	opts = opts.withDefaults()

	var (
		networkConfig = mustParseNetworkConfigf(`
            vpn:
              public_addr: %q
              tun:
                device: %q
            storage:
              allocations:
                - data_path: %s
                  meta_path: %s
                  capacity: 1
                - data_path: %s
                  meta_path: %s
                  capacity: 1
                - data_path: %s
                  meta_path: %s
                  capacity: 1
            `,
			newPublicAddr(),
			newTunDevice(),
			h.mkDir(t, "data").Path,
			h.mkDir(t, "meta").Path,
			h.mkDir(t, "data").Path,
			h.mkDir(t, "meta").Path,
			h.mkDir(t, "data").Path,
			h.mkDir(t, "meta").Path,
		)

		stateDir            = h.mkDir(t, "state")
		runtimeDir          = h.mkDir(t, "runtime")
		childrenLogFilePath = filepath.Join(runtimeDir.Path, "children.log")

		ipNet    = newIPNet()
		hostName = nebula.HostName(hostNameStr)

		childrenOpts *children.Opts
	)

	childrenLogFile, err := os.Create(childrenLogFilePath)
	if err != nil {
		t.Fatalf("creating %q: %v", childrenLogFilePath, err)
	}
	t.Cleanup(func() {
		if err := childrenLogFile.Close(); err != nil {
			t.Errorf("closing %q: %v", childrenLogFilePath, err)
		}
	})

	if os.Getenv("ISLE_INTEGRATION_TEST_CHILDREN_LOG_STDOUT") == "" {
		childrenOpts = &children.Opts{
			Stdout: childrenLogFile,
			Stderr: childrenLogFile,
		}
	} else {
		childrenOpts = &children.Opts{
			Stdout: io.MultiWriter(os.Stdout, childrenLogFile),
			Stderr: io.MultiWriter(os.Stdout, childrenLogFile),
		}
	}

	networkOpts := &Opts{
		ChildrenOpts: childrenOpts,
	}

	network, err := Create(
		h.ctx,
		h.logger.WithNamespace("network"),
		networkConfig,
		getEnvBinDirPath(),
		stateDir,
		runtimeDir,
		opts.creationParams,
		ipNet,
		hostName,
		networkOpts,
	)
	if err != nil {
		t.Fatalf("creating Network: %v", err)
	}

	if !opts.manualShutdown {
		t.Cleanup(func() {
			t.Log("Shutting down Network")
			if err := network.Shutdown(); err != nil {
				t.Logf("Shutting down Network failed: %v", err)
			}
		})
	}

	return integrationHarnessNetwork{
		network,
		opts.creationParams,
		networkConfig,
		stateDir,
		runtimeDir,
		networkOpts,
	}
}