// Copyright 2020 The Monogon Project Authors.
//
// SPDX-License-Identifier: Apache-2.0
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package main

import (
	"context"
	"errors"
	"flag"
	"fmt"
	"log"
	"net"
	"os"
	"os/exec"
	"os/signal"
	"strconv"
	"strings"
	"time"

	"source.monogon.dev/metropolis/cli/flagdefs"
	metroctl "source.monogon.dev/metropolis/cli/metroctl/core"
	"source.monogon.dev/metropolis/node"
	cpb "source.monogon.dev/metropolis/proto/common"
	mlaunch "source.monogon.dev/metropolis/test/launch"
)

const maxNodes = 256

func nodeSetFlag(p *[]int, name string, usage string) {
	flag.Func(name, usage, func(val string) error {
		for _, part := range strings.Split(val, ",") {
			part = strings.TrimSpace(part)
			if part == "" {
				continue
			}
			startStr, endStr, ok := strings.Cut(part, "-")
			if !ok {
				endStr = startStr
			}
			start, err := strconv.Atoi(startStr)
			if err != nil {
				return err
			}
			end, err := strconv.Atoi(endStr)
			if err != nil {
				return err
			}
			if end >= maxNodes {
				return fmt.Errorf("node index %v out of range, there can be at most %v nodes", end, maxNodes)
			}
			if end < start {
				return fmt.Errorf("invalid range %q, end is smaller than start", part)
			}
			for i := start; i <= end; i++ {
				*p = append(*p, i)
			}
		}
		return nil
	})
}

func sizeFlagMiB(p *int, name string, usage string) {
	flag.Func(name, usage, func(val string) error {
		multiplier := 1
		switch {
		case strings.HasSuffix(val, "M"):
		case strings.HasSuffix(val, "G"):
			multiplier = 1024
		default:
			return errors.New("must have suffix M for MiB or G for GiB")
		}
		intVal, err := strconv.Atoi(val[:len(val)-1])
		if err != nil {
			return err
		}
		*p = multiplier * intVal
		return nil
	})
}

func main() {
	clusterConfig := cpb.ClusterConfiguration{}
	opts := mlaunch.ClusterOptions{
		NodeLogsToFiles:             true,
		InitialClusterConfiguration: &clusterConfig,
	}
	var consensusMemberList, kubernetesControllerList, kubernetesWorkerList []int

	flag.IntVar(&opts.NumNodes, "num-nodes", 3, "Number of cluster nodes")
	flagdefs.TPMModeVar(flag.CommandLine, &clusterConfig.TpmMode, "tpm-mode", cpb.ClusterConfiguration_TPM_MODE_REQUIRED, "TPM mode to set on cluster")
	flagdefs.StorageSecurityPolicyVar(flag.CommandLine, &clusterConfig.StorageSecurityPolicy, "storage-security", cpb.ClusterConfiguration_STORAGE_SECURITY_POLICY_NEEDS_INSECURE, "Storage security policy to set on cluster")
	flag.IntVar(&opts.Node.CPUs, "cpu", 1, "Number of virtual CPUs of each node")
	flag.IntVar(&opts.Node.ThreadsPerCPU, "threads-per-cpu", 1, "Number of threads per CPU")
	sizeFlagMiB(&opts.Node.MemoryMiB, "ram", "RAM size of each node, with suffix M for MiB or G for GiB")
	nodeSetFlag(&consensusMemberList, "consensus-member", "List of nodes which get the Consensus Member role. Example: 0,3-5")
	nodeSetFlag(&kubernetesControllerList, "kubernetes-controller", "List of nodes which get the Kubernetes Controller role. Example: 0,3-5")
	nodeSetFlag(&kubernetesWorkerList, "kubernetes-worker", "List of nodes which get the Kubernetes Worker role. Example: 0,3-5")
	flag.Parse()

	if opts.NumNodes >= maxNodes {
		log.Fatalf("num-nodes (%v) is too large, there can be at most %v nodes", opts.NumNodes, maxNodes)
	}
	for _, list := range [][]int{consensusMemberList, kubernetesControllerList, kubernetesWorkerList} {
		for i := len(list) - 1; i >= 0; i-- {
			if list[i] >= opts.NumNodes {
				log.Fatalf("Node index %v out of range, can be at most %v", list[i], opts.NumNodes-1)
			}
		}
	}

	ctx, _ := signal.NotifyContext(context.Background(), os.Interrupt)
	cl, err := mlaunch.LaunchCluster(ctx, opts)
	if err != nil {
		log.Fatalf("LaunchCluster: %v", err)
	}

	for _, node := range consensusMemberList {
		cl.MakeConsensusMember(ctx, cl.NodeIDs[node])
	}
	for _, node := range kubernetesControllerList {
		cl.MakeKubernetesController(ctx, cl.NodeIDs[node])
	}
	for _, node := range kubernetesWorkerList {
		cl.MakeKubernetesWorker(ctx, cl.NodeIDs[node])
	}

	wpath, err := cl.MakeMetroctlWrapper()
	if err != nil {
		log.Fatalf("MakeWrapper: %v", err)
	}

	apiserver := cl.Nodes[cl.NodeIDs[0]].ManagementAddress
	// Wait for the API server to start listening.
	for {
		conn, err := cl.DialNode(ctx, net.JoinHostPort(apiserver, node.KubernetesAPIWrappedPort.PortString()))
		if err == nil {
			conn.Close()
			break
		}
		time.Sleep(100 * time.Millisecond)
	}

	// If the user has metroctl in their path, use the metroctl from path as
	// a credential plugin. Otherwise use the path to the currently-running
	// metroctl.
	metroctlPath := "metroctl"
	if _, err := exec.LookPath("metroctl"); err != nil {
		metroctlPath, err = os.Executable()
		if err != nil {
			log.Fatalf("Failed to create kubectl entry as metroctl is neither in PATH nor can its absolute path be determined: %v", err)
		}
	}

	configName := "launch-cluster"
	if err := metroctl.InstallKubeletConfig(ctx, metroctlPath, cl.ConnectOptions(), configName, apiserver); err != nil {
		log.Fatalf("InstallKubeletConfig: %v", err)
	}

	log.Printf("Launch: Cluster running!")
	log.Printf("  To access cluster use: metroctl %s", cl.MetroctlFlags())
	log.Printf("  Or use this handy wrapper: %s", wpath)
	log.Printf("  To access Kubernetes, use kubectl --context=%s", configName)

	<-ctx.Done()
	cl.Close()
}