/*
Copyright © 2022 Joel D. Elkins <joel@elkins.co>

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
*/
package container

import (
	"context"
	"fmt"
	"net"
	"os/exec"

	"gitea.elkins.co/Networking/ccl/internal/pkg/command"
	"gitea.elkins.co/Networking/ccl/internal/pkg/network"
	"github.com/containers/common/libnetwork/types"
	"github.com/containers/podman/v4/libpod/define"
	"github.com/containers/podman/v4/pkg/bindings/containers"
	"github.com/containers/podman/v4/pkg/bindings/images"
	"github.com/containers/podman/v4/pkg/specgen"
	spec "github.com/opencontainers/runtime-spec/specs-go"
	log "github.com/sirupsen/logrus"
)

type Container struct {
	Category  string
	Name      string
	Image     string
	Hostname  string
	Command   []string
	Arguments string
	Networks  []network.Network
	Env       map[string]string
	Mounts    []spec.Mount
	Restart   string
	Umask     uint
	User      string

	conn  context.Context
	cdata *define.InspectContainerData
}

func (c *Container) Init(conn context.Context, nets []network.Network) error {
	// initialize user-provided definitions
	for i := range c.Networks {
		var n *network.Network
		for j := range nets {
			if nets[j].Name == c.Networks[i].Name {
				n = &nets[j]
			}
		}
		if n == nil {
			continue
		}
		if len(c.Networks[i].DNS) == 0 {
			c.Networks[i].DNS = n.DNS
		}
		if !c.Networks[i].IPv6.Valid {
			if n.IPv6.Valid {
				c.Networks[i].IPv6 = n.IPv6
			} else {
				c.Networks[i].IPv6.SetValid(true)
			}
		}
	}
	for i := range c.Mounts {
		if c.Mounts[i].Type == "" {
			c.Mounts[i].Type = "bind"
		}
	}

	c.conn = conn
	if c.Umask == 0 {
		c.Umask = 0o022
	}
	return c.populateCData()
}

func (c *Container) LogEntry() *log.Entry {
	f := log.Fields{
		"container": c.Name,
	}
	if c.cdata != nil {
		f["id"] = c.cdata.ID
	}
	if c.cdata.State != nil {
		f["state"] = c.cdata.State.Status
	}
	return log.WithFields(f)
}

func (c *Container) pull() error {
	_, err := images.Pull(c.conn, c.Image, &images.PullOptions{})
	return err
	// if err != nil {
	// 	return err
	// }
	// return c.populateCData()
}

func (c *Container) PullCommands() []command.Command {
	return []command.Command{
		command.NewErrFunc("do_pull", func() error {
			return c.pull()
		}),
	}
}

func (c *Container) CreateCommands() []command.Command {
	if c.Image == "" {
		return []command.Command{
			command.NewErrFunc("image_error", func() error {
				return fmt.Errorf("Image not configured")
			}),
		}
	}
	sysctl := map[string]string{}
	nets := map[string]types.PerNetworkOptions{}
	dns := []net.IP{}
	for i := range c.Networks {
		if !c.Networks[i].IPv6.Bool {
			sysctl["net.ipv6.conf."+c.Networks[i].Name+".accept_ra"] = "0"
		}
		ips := []net.IP{}
		if c.Networks[i].IPv4Address != nil {
			ips = append(ips, c.Networks[i].IPv4Address)
		}
		if c.Networks[i].IPv6Address != nil {
			ips = append(ips, c.Networks[i].IPv6Address)
		}
		nets[c.Networks[i].Name] = types.PerNetworkOptions{
			StaticIPs:     ips,
			InterfaceName: c.Networks[i].Name,
		}
		dns = append(dns, c.Networks[i].DNS...)
	}

	spec := specgen.SpecGenerator{
		ContainerBasicConfig: specgen.ContainerBasicConfig{
			Name:          c.Name,
			UtsNS:         specgen.Namespace{NSMode: specgen.Private},
			Hostname:      c.Hostname,
			RawImageName:  c.Image,
			RestartPolicy: c.Restart,
			Sysctl:        sysctl,
			Env:           c.Env,
			Command:       c.Command,
		},
		ContainerStorageConfig: specgen.ContainerStorageConfig{
			Image:  c.Image,
			Mounts: c.Mounts,
		},
		ContainerNetworkConfig: specgen.ContainerNetworkConfig{
			Networks:   nets,
			DNSServers: dns,
		},
		ContainerSecurityConfig: specgen.ContainerSecurityConfig{
			User:  c.User,
			Umask: fmt.Sprintf("%#o", c.Umask),
		},
	}
	if err := spec.Validate(); err != nil {
		c.LogEntry().WithField("error", err).Warnf("Spec does not validate")
	}
	return []command.Command{
		command.NewErrFunc("bail_if_exists", func() error {
			if ex, err := containers.Exists(c.conn, c.Name, &containers.ExistsOptions{}); err != nil || ex {
				if err != nil {
					return err
				}
				return fmt.Errorf("Container %s exists already", c.Name)
			}
			return nil
		}),
		command.NewErrFunc("pull_if_necessary", func() error {
			if ex, err := images.Exists(c.conn, c.Image, &images.ExistsOptions{}); err != nil || !ex {
				if err != nil {
					return err
				}
				return c.pull()
			}
			return nil
		}),
		command.NewErrFunc("do_create", func() error {
			_, err := containers.CreateWithSpec(c.conn, &spec, nil)
			if err != nil {
				return err
			}
			return c.populateCData()
		}),
	}
}

func (c *Container) RecreateCommands() []command.Command {
	wasRunning := false
	return []command.Command{
		command.NewFunc("stash_run_state", func() string {
			wasRunning = c.IsRunning()
			runMsg := "not running. Will not start it after recreating."
			if wasRunning {
				runMsg = "running. Will restart after recreating."
			}
			return fmt.Sprintf("Container %s is %s", c.Name, runMsg)
		}),
		command.NewSet(c.DestroyCommands()),
		command.NewSet(c.CreateCommands()),
		command.NewConditional("start_if_was_running",
			func() bool { return wasRunning },
			command.NewSet(c.StartCommands()),
			command.NewNop(),
		),
	}
}

func (c *Container) DestroyCommands() []command.Command {
	cmds := c.StopCommands()
	cmds = append(cmds, command.NewErrFunc("remove_if_exists", func() error {
		if c.cdata.ID == "" {
			return nil
		}
		yes := true
		_, err := containers.Remove(c.conn, c.cdata.ID, &containers.RemoveOptions{Force: &yes})
		return err
	}))
	return cmds
}

func (c *Container) StartCommands() []command.Command {
	return []command.Command{
		command.NewErrFunc("start_container", func() error {
			if c.cdata.State != nil && c.cdata.State.Running {
				return nil
			}
			err := containers.Start(c.conn, c.cdata.ID, nil)
			if err != nil {
				return err
			}
			_, err = containers.Wait(c.conn, c.cdata.ID, &containers.WaitOptions{Condition: []define.ContainerStatus{define.ContainerStateRunning}})
			if err != nil {
				return err
			}
			err = c.populateCData()
			if err != nil {
				return err
			}
			err = c.assureNetNS()
			if err != nil {
				return err
			}
			return nil
		}),
	}
}

func (c *Container) RestartCommands() []command.Command {
	return []command.Command{
		command.NewSet(c.StopCommands()),
		command.NewSet(c.StartCommands()),
	}
}

func (c *Container) IsRunning() bool {
	if c.cdata != nil && c.cdata.State != nil {
		return c.cdata.State.Running
	}
	return false
}

func (c *Container) IsCreated() bool {
	if c.cdata == nil || c.cdata.ID == "" {
		return false
	}
	return true
}

func (c *Container) UpdateCommands() []command.Command {
	wasRunning := false
	return []command.Command{
		command.NewErrFunc("do_update_and_stop", func() error {
			err := c.pull()
			if err != nil {
				return err
			}
			wasRunning = c.cdata != nil && c.cdata.State != nil && c.cdata.State.Running
			if wasRunning {
				var timeout uint = 10
				err := containers.Stop(c.conn, c.cdata.ID, &containers.StopOptions{Timeout: &timeout})
				if err != nil {
					return err
				}
				_, err = containers.Remove(c.conn, c.cdata.ID, nil)
				if err != nil {
					return err
				}
				c.cdata = nil
			}
			return nil
		}),
		command.NewSet(c.CreateCommands()),
		command.NewConditional("restart_if_was_running",
			func() bool { return wasRunning },
			command.NewSet(c.StartCommands()),
			command.NewNop(),
		),
	}
}

func (c *Container) StopCommands() []command.Command {
	return []command.Command{
		command.NewErrFunc("do_stop", func() error {
			if c.IsRunning() {
				var timeout uint = 10
				err := containers.Stop(c.conn, c.cdata.ID, &containers.StopOptions{Timeout: &timeout})
				if err != nil {
					return err
				}
				_, err = containers.Wait(c.conn, c.cdata.ID, &containers.WaitOptions{Condition: []define.ContainerStatus{define.ContainerStateExited}})
				if err != nil {
					return err
				}
				return c.populateCData()
			}
			log.WithFields(log.Fields{
				"container": c.Name,
				"id":        c.cdata.ID,
			}).Debugf("Container stopped but wasn't running. Not a problem.")
			return nil
		}),
	}
}

func (c *Container) populateCData() error {
	// TODO: locking
	var err error
	no := false
	c.cdata, err = containers.Inspect(c.conn, c.Name, &containers.InspectOptions{Size: &no})
	if err != nil {
		return err
	}
	return nil
}

func (c *Container) Pid() int {
	if c.cdata != nil && c.cdata.State != nil {
		return c.cdata.State.Pid
	}
	return 0
}

func (c *Container) assureNetNS() error {
	if nil == c.cdata || nil == c.cdata.NetworkSettings {
		return fmt.Errorf("Network namespace not available!")
	}
	netns := c.cdata.NetworkSettings.SandboxKey
	if err := exec.Command("rm", "-f", "/var/run/netns/"+c.Name).Run(); err != nil {
		return err
	}
	if err := exec.Command("ln", "-sf", netns, "/var/run/netns/"+c.Name).Run(); err != nil {
		return err
	}
	return nil
}