package controller

import (
	"context"
	"os/exec"
	"time"

	"git.giftfish.de/ston1th/vipman/pkg/cluster"
	"git.giftfish.de/ston1th/vipman/pkg/config"
	"git.giftfish.de/ston1th/vipman/pkg/vip"
	"github.com/go-logr/logr"
)

func NewVIPController(cfg *config.Config) (callbacks cluster.Callbacks, err error) {
	n, err := vip.NewNetworkWithLabel(cfg.Interface, cfg.Label)
	if err != nil {
		return
	}
	callbacks = cluster.Callbacks{
		Leader: func(ctx context.Context, cc cluster.CallbackContext) {
			t := time.NewTicker(time.Second * 10)
			if len(cfg.LeaderHook) > 0 {
				go func() {
					err := exec.CommandContext(ctx, cfg.LeaderHook[0], cfg.LeaderHook[1:]...).Run()
					if err != nil {
						cc.Error(err, "error running hook", "leaderHook", cfg.LeaderHook)
					}
				}()
			}
			for {
				cc.Info("leading", "id", cc.ID())
				addIPs(cc, n, cfg.VirtualIPs)
				select {
				case <-ctx.Done():
					t.Stop()
					deleteIPs(cc, n, cfg.VirtualIPs)
					cc.Info("leading canceled", "id", cc.ID())
					return
				case <-t.C:
				}
			}
		},
		Follower: func(ctx context.Context, cc cluster.CallbackContext) {
			t := time.NewTicker(time.Second * 10)
			if len(cfg.FollowerHook) > 0 {
				go func() {
					err := exec.CommandContext(ctx, cfg.FollowerHook[0], cfg.FollowerHook[1:]...).Run()
					if err != nil {
						cc.Error(err, "error running hook", "followerHook", cfg.FollowerHook)
					}
				}()
			}
			for {
				cc.Info("following", "id", cc.ID())
				deleteIPs(cc, n, cfg.VirtualIPs)
				select {
				case <-ctx.Done():
					t.Stop()
					cc.Info("following canceled", "id", cc.ID())
					return
				case <-t.C:
				}
			}
		},
		Cleanup: func(ctx context.Context, cc cluster.CallbackContext) {
			deleteIPs(cc, n, cfg.VirtualIPs)
		},
	}
	return
}

func addIPs(log logr.Logger, n *vip.Network, cidrs []string) error {
	for _, cidr := range cidrs {
		err := n.AddIP(cidr)
		if err != nil {
			log.Error(err, "adding ip", "interface", n.Interface(), "ip", cidr)
		}
	}
	return nil
}

func deleteIPs(log logr.Logger, n *vip.Network, cidrs []string) error {
	for _, cidr := range cidrs {
		err := n.DeleteIP(cidr)
		if err != nil {
			log.Error(err, "deleting ip", "interface", n.Interface(), "ip", cidr)
		}
	}
	return nil
}