package resource

import (
	"context"
	"fmt"
	"strconv"
	"strings"

	"github.com/derailed/k9s/internal/k8s"
	v1 "k8s.io/api/core/v1"
	mv1beta1 "k8s.io/metrics/pkg/apis/metrics/v1beta1"
)

type (
	// Container represents a container on a pod.
	Container struct {
		*Base

		pod      *v1.Pod
		instance v1.Container
		metrics  *mv1beta1.PodMetrics
	}
)

// NewContainerList returns a collection of container.
func NewContainerList(c Connection, pod *v1.Pod) List {
	return NewList(
		"",
		"co",
		NewContainer(c, pod),
		0,
	)
}

// NewContainer returns a new set of containers.
func NewContainer(c Connection, pod *v1.Pod) *Container {
	co := Container{
		Base: &Base{Connection: c, Resource: k8s.NewPod(c)},
		pod:  pod,
	}
	co.Factory = &co

	return &co
}

// New builds a new Container instance from a k8s resource.
func (r *Container) New(i interface{}) Columnar {
	co := NewContainer(r.Connection, r.pod)
	co.instance = i.(v1.Container)
	co.path = r.namespacedName(r.pod.ObjectMeta) + ":" + co.instance.Name

	return co
}

// SetPodMetrics set the current k8s resource metrics on associated pod.
func (r *Container) SetPodMetrics(m *mv1beta1.PodMetrics) {
	r.metrics = m
}

// Marshal resource to yaml.
func (r *Container) Marshal(path string) (string, error) {
	return "", nil
}

// // PodLogs tail logs for all containers in a running Pod.
// func (r *Container) PodLogs(ctx context.Context, c chan<- string, ns, n string, lines int64, prev bool) error {
// 	return nil
// }

// Logs tails a given container logs
func (r *Container) Logs(ctx context.Context, c chan<- string, opts LogOptions) error {
	res, ok := r.Resource.(k8s.Loggable)
	if !ok {
		return fmt.Errorf("Resource %T is not Loggable", r.Resource)
	}

	return tailLogs(ctx, res, c, opts)
}

// List resources for a given namespace.
func (r *Container) List(ns string) (Columnars, error) {
	icos := r.pod.Spec.InitContainers
	cos := r.pod.Spec.Containers

	cc := make(Columnars, 0, len(icos)+len(cos))
	for _, co := range icos {
		ci := r.New(co)
		cc = append(cc, ci)
	}
	for _, co := range cos {
		cc = append(cc, r.New(co))
	}

	return cc, nil
}

// Header return resource header.
func (*Container) Header(ns string) Row {
	return append(Row{},
		"NAME",
		"IMAGE",
		"READY",
		"STATE",
		"RS",
		"PROBES(L:R)",
		"CPU",
		"MEM",
		"%CPU",
		"%MEM",
		"PORTS",
		"AGE",
	)
}

// NumCols designates if column is numerical.
func (*Container) NumCols(n string) map[string]bool {
	return map[string]bool{
		"CPU":  true,
		"MEM":  true,
		"%CPU": true,
		"%MEM": true,
		"RS":   true,
	}
}

// Fields retrieves displayable fields.
func (r *Container) Fields(ns string) Row {
	ff := make(Row, 0, len(r.Header(ns)))
	i := r.instance

	c, p := gatherMetrics(i, r.metrics)

	ready, state, restarts := "false", MissingValue, "0"
	cs := getContainerStatus(i.Name, r.pod.Status)
	if cs != nil {
		ready, state, restarts = boolToStr(cs.Ready), toState(cs.State), strconv.Itoa(int(cs.RestartCount))
	}

	return append(ff,
		i.Name,
		i.Image,
		ready,
		state,
		restarts,
		probe(i.LivenessProbe)+":"+probe(i.ReadinessProbe),
		c.cpu,
		c.mem,
		p.cpu,
		p.mem,
		toStrPorts(i.Ports),
		toAge(r.pod.CreationTimestamp),
	)
}

// ----------------------------------------------------------------------------
// Helpers...

func gatherMetrics(co v1.Container, mx *mv1beta1.PodMetrics) (c, p metric) {
	c, p = noMetric(), noMetric()
	if mx == nil {
		return
	}

	var (
		cpu int64
		mem float64
	)
	for _, c := range mx.Containers {
		if c.Name == co.Name {
			cpu = c.Usage.Cpu().MilliValue()
			mem = k8s.ToMB(c.Usage.Memory().Value())
			break
		}
	}
	c = metric{
		cpu: ToMillicore(cpu),
		mem: ToMi(mem),
	}

	rcpu, rmem := containerResources(co)
	if rcpu != nil {
		p.cpu = AsPerc(toPerc(float64(cpu), float64(rcpu.MilliValue())))
	}
	if rmem != nil {
		p.mem = AsPerc(toPerc(mem, k8s.ToMB(rmem.Value())))
	}

	return
}

func getContainerStatus(co string, status v1.PodStatus) *v1.ContainerStatus {
	for _, c := range status.ContainerStatuses {
		if c.Name == co {
			return &c
		}
	}

	for _, c := range status.InitContainerStatuses {
		if c.Name == co {
			return &c
		}
	}

	return nil
}

func toStrPorts(pp []v1.ContainerPort) string {
	ports := make([]string, len(pp))
	for i, p := range pp {
		if len(p.Name) > 0 {
			ports[i] = p.Name + ":"
		}
		ports[i] += strconv.Itoa(int(p.ContainerPort))
		if p.Protocol != "TCP" {
			ports[i] += "╱" + string(p.Protocol)
		}
	}

	return strings.Join(ports, ",")
}

func toState(s v1.ContainerState) string {
	switch {
	case s.Waiting != nil:
		if s.Waiting.Reason != "" {
			return s.Waiting.Reason
		}
		return "Waiting"

	case s.Terminated != nil:
		if s.Terminated.Reason != "" {
			return s.Terminated.Reason
		}
		return "Terminated"
	case s.Running != nil:
		return "Running"
	default:
		return MissingValue
	}
}

func toRes(r v1.ResourceList) (string, string) {
	cpu, mem := r[v1.ResourceCPU], r[v1.ResourceMemory]

	return ToMillicore(cpu.MilliValue()), ToMi(k8s.ToMB(mem.Value()))
}

func probe(p *v1.Probe) string {
	if p == nil {
		return "off"
	}
	return "on"
}

func asMi(v int64) float64 {
	return float64(v) / 1024 * 1024
}