package daemon

import (
	"errors"
	"fmt"
	"strconv"
	"strings"

	"github.com/Sirupsen/logrus"
	"github.com/docker/docker/container"
	"github.com/docker/docker/image"
	"github.com/docker/docker/pkg/graphdb"
	"github.com/docker/engine-api/types"
	"github.com/docker/engine-api/types/filters"
	"github.com/docker/go-connections/nat"
)

// iterationAction represents possible outcomes happening during the container iteration.
type iterationAction int

// containerReducer represents a reducer for a container.
// Returns the object to serialize by the api.
type containerReducer func(*container.Container, *listContext) (*types.Container, error)

const (
	// includeContainer is the action to include a container in the reducer.
	includeContainer iterationAction = iota
	// excludeContainer is the action to exclude a container in the reducer.
	excludeContainer
	// stopIteration is the action to stop iterating over the list of containers.
	stopIteration
)

// errStopIteration makes the iterator to stop without returning an error.
var errStopIteration = errors.New("container list iteration stopped")

// List returns an array of all containers registered in the daemon.
func (daemon *Daemon) List() []*container.Container {
	return daemon.containers.List()
}

// ContainersConfig is the filtering specified by the user to iterate over containers.
type ContainersConfig struct {
	// if true show all containers, otherwise only running containers.
	All bool
	// show all containers created after this container id
	Since string
	// show all containers created before this container id
	Before string
	// number of containers to return at most
	Limit int
	// if true include the sizes of the containers
	Size bool
	// return only containers that match filters
	Filters string
}

// listContext is the daemon generated filtering to iterate over containers.
// This is created based on the user specification.
type listContext struct {
	// idx is the container iteration index for this context
	idx int
	// ancestorFilter tells whether it should check ancestors or not
	ancestorFilter bool
	// names is a list of container names to filter with
	names map[string][]string
	// images is a list of images to filter with
	images map[image.ID]bool
	// filters is a collection of arguments to filter with, specified by the user
	filters filters.Args
	// exitAllowed is a list of exit codes allowed to filter with
	exitAllowed []int
	// beforeFilter is a filter to ignore containers that appear before the one given
	// this is used for --filter=before= and --before=, the latter is deprecated.
	beforeFilter *container.Container
	// sinceFilter is a filter to stop the filtering when the iterator arrive to the given container
	// this is used for --filter=since= and --since=, the latter is deprecated.
	sinceFilter *container.Container
	// ContainersConfig is the filters set by the user
	*ContainersConfig
}

// Containers returns the list of containers to show given the user's filtering.
func (daemon *Daemon) Containers(config *ContainersConfig) ([]*types.Container, error) {
	return daemon.reduceContainers(config, daemon.transformContainer)
}

// reduceContainer parses the user filtering and generates the list of containers to return based on a reducer.
func (daemon *Daemon) reduceContainers(config *ContainersConfig, reducer containerReducer) ([]*types.Container, error) {
	containers := []*types.Container{}

	ctx, err := daemon.foldFilter(config)
	if err != nil {
		return nil, err
	}

	for _, container := range daemon.List() {
		t, err := daemon.reducePsContainer(container, ctx, reducer)
		if err != nil {
			if err != errStopIteration {
				return nil, err
			}
			break
		}
		if t != nil {
			containers = append(containers, t)
			ctx.idx++
		}
	}
	return containers, nil
}

// reducePsContainer is the basic representation for a container as expected by the ps command.
func (daemon *Daemon) reducePsContainer(container *container.Container, ctx *listContext, reducer containerReducer) (*types.Container, error) {
	container.Lock()
	defer container.Unlock()

	// filter containers to return
	action := includeContainerInList(container, ctx)
	switch action {
	case excludeContainer:
		return nil, nil
	case stopIteration:
		return nil, errStopIteration
	}

	// transform internal container struct into api structs
	return reducer(container, ctx)
}

// foldFilter generates the container filter based in the user's filtering options.
func (daemon *Daemon) foldFilter(config *ContainersConfig) (*listContext, error) {
	psFilters, err := filters.FromParam(config.Filters)
	if err != nil {
		return nil, err
	}

	var filtExited []int
	err = psFilters.WalkValues("exited", func(value string) error {
		code, err := strconv.Atoi(value)
		if err != nil {
			return err
		}
		filtExited = append(filtExited, code)
		return nil
	})
	if err != nil {
		return nil, err
	}

	err = psFilters.WalkValues("status", func(value string) error {
		if !container.IsValidStateString(value) {
			return fmt.Errorf("Unrecognised filter value for status: %s", value)
		}

		config.All = true
		return nil
	})
	if err != nil {
		return nil, err
	}

	var beforeContFilter, sinceContFilter *container.Container
	err = psFilters.WalkValues("before", func(value string) error {
		beforeContFilter, err = daemon.GetContainer(value)
		return err
	})
	if err != nil {
		return nil, err
	}

	err = psFilters.WalkValues("since", func(value string) error {
		sinceContFilter, err = daemon.GetContainer(value)
		return err
	})
	if err != nil {
		return nil, err
	}

	imagesFilter := map[image.ID]bool{}
	var ancestorFilter bool
	if psFilters.Include("ancestor") {
		ancestorFilter = true
		psFilters.WalkValues("ancestor", func(ancestor string) error {
			id, err := daemon.GetImageID(ancestor)
			if err != nil {
				logrus.Warnf("Error while looking up for image %v", ancestor)
				return nil
			}
			if imagesFilter[id] {
				// Already seen this ancestor, skip it
				return nil
			}
			// Then walk down the graph and put the imageIds in imagesFilter
			populateImageFilterByParents(imagesFilter, id, daemon.imageStore.Children)
			return nil
		})
	}

	names := make(map[string][]string)
	daemon.containerGraph().Walk("/", func(p string, e *graphdb.Entity) error {
		names[e.ID()] = append(names[e.ID()], p)
		return nil
	}, 1)

	if config.Before != "" && beforeContFilter == nil {
		beforeContFilter, err = daemon.GetContainer(config.Before)
		if err != nil {
			return nil, err
		}
	}

	if config.Since != "" && sinceContFilter == nil {
		sinceContFilter, err = daemon.GetContainer(config.Since)
		if err != nil {
			return nil, err
		}
	}

	return &listContext{
		filters:          psFilters,
		ancestorFilter:   ancestorFilter,
		names:            names,
		images:           imagesFilter,
		exitAllowed:      filtExited,
		beforeFilter:     beforeContFilter,
		sinceFilter:      sinceContFilter,
		ContainersConfig: config,
	}, nil
}

// includeContainerInList decides whether a containers should be include in the output or not based in the filter.
// It also decides if the iteration should be stopped or not.
func includeContainerInList(container *container.Container, ctx *listContext) iterationAction {
	// Do not include container if it's stopped and we're not filters
	if !container.Running && !ctx.All && ctx.Limit <= 0 && ctx.beforeFilter == nil && ctx.sinceFilter == nil {
		return excludeContainer
	}

	// Do not include container if the name doesn't match
	if !ctx.filters.Match("name", container.Name) {
		return excludeContainer
	}

	// Do not include container if the id doesn't match
	if !ctx.filters.Match("id", container.ID) {
		return excludeContainer
	}

	// Do not include container if any of the labels don't match
	if !ctx.filters.MatchKVList("label", container.Config.Labels) {
		return excludeContainer
	}

	// Do not include container if the isolation mode doesn't match
	if excludeContainer == excludeByIsolation(container, ctx) {
		return excludeContainer
	}

	// Do not include container if it's in the list before the filter container.
	// Set the filter container to nil to include the rest of containers after this one.
	if ctx.beforeFilter != nil {
		if container.ID == ctx.beforeFilter.ID {
			ctx.beforeFilter = nil
		}
		return excludeContainer
	}

	// Stop iteration when the container arrives to the filter container
	if ctx.sinceFilter != nil {
		if container.ID == ctx.sinceFilter.ID {
			return stopIteration
		}
	}

	// Stop iteration when the index is over the limit
	if ctx.Limit > 0 && ctx.idx == ctx.Limit {
		return stopIteration
	}

	// Do not include container if its exit code is not in the filter
	if len(ctx.exitAllowed) > 0 {
		shouldSkip := true
		for _, code := range ctx.exitAllowed {
			if code == container.ExitCode && !container.Running {
				shouldSkip = false
				break
			}
		}
		if shouldSkip {
			return excludeContainer
		}
	}

	// Do not include container if its status doesn't match the filter
	if !ctx.filters.Match("status", container.State.StateString()) {
		return excludeContainer
	}

	if ctx.ancestorFilter {
		if len(ctx.images) == 0 {
			return excludeContainer
		}
		if !ctx.images[container.ImageID] {
			return excludeContainer
		}
	}

	return includeContainer
}

// transformContainer generates the container type expected by the docker ps command.
func (daemon *Daemon) transformContainer(container *container.Container, ctx *listContext) (*types.Container, error) {
	newC := &types.Container{
		ID:      container.ID,
		Names:   ctx.names[container.ID],
		ImageID: container.ImageID.String(),
	}
	if newC.Names == nil {
		// Dead containers will often have no name, so make sure the response isn't  null
		newC.Names = []string{}
	}

	image := container.Config.Image // if possible keep the original ref
	if image != container.ImageID.String() {
		id, err := daemon.GetImageID(image)
		if _, isDNE := err.(ErrImageDoesNotExist); err != nil && !isDNE {
			return nil, err
		}
		if err != nil || id != container.ImageID {
			image = container.ImageID.String()
		}
	}
	newC.Image = image

	if len(container.Args) > 0 {
		args := []string{}
		for _, arg := range container.Args {
			if strings.Contains(arg, " ") {
				args = append(args, fmt.Sprintf("'%s'", arg))
			} else {
				args = append(args, arg)
			}
		}
		argsAsString := strings.Join(args, " ")

		newC.Command = fmt.Sprintf("%s %s", container.Path, argsAsString)
	} else {
		newC.Command = container.Path
	}
	newC.Created = container.Created.Unix()
	newC.Status = container.State.String()
	newC.HostConfig.NetworkMode = string(container.HostConfig.NetworkMode)
	newC.NetworkSettings = &types.SummaryNetworkSettings{container.NetworkSettings.Networks}

	newC.Ports = []types.Port{}
	for port, bindings := range container.NetworkSettings.Ports {
		p, err := nat.ParsePort(port.Port())
		if err != nil {
			return nil, err
		}
		if len(bindings) == 0 {
			newC.Ports = append(newC.Ports, types.Port{
				PrivatePort: p,
				Type:        port.Proto(),
			})
			continue
		}
		for _, binding := range bindings {
			h, err := nat.ParsePort(binding.HostPort)
			if err != nil {
				return nil, err
			}
			newC.Ports = append(newC.Ports, types.Port{
				PrivatePort: p,
				PublicPort:  h,
				Type:        port.Proto(),
				IP:          binding.HostIP,
			})
		}
	}

	if ctx.Size {
		sizeRw, sizeRootFs := daemon.getSize(container)
		newC.SizeRw = sizeRw
		newC.SizeRootFs = sizeRootFs
	}
	newC.Labels = container.Config.Labels

	return newC, nil
}

// Volumes lists known volumes, using the filter to restrict the range
// of volumes returned.
func (daemon *Daemon) Volumes(filter string) ([]*types.Volume, []string, error) {
	var volumesOut []*types.Volume
	volFilters, err := filters.FromParam(filter)
	if err != nil {
		return nil, nil, err
	}

	filterUsed := volFilters.Include("dangling") &&
		(volFilters.ExactMatch("dangling", "true") || volFilters.ExactMatch("dangling", "1"))

	volumes, warnings, err := daemon.volumes.List()
	if err != nil {
		return nil, nil, err
	}
	if filterUsed {
		volumes = daemon.volumes.FilterByUsed(volumes)
	}
	for _, v := range volumes {
		volumesOut = append(volumesOut, volumeToAPIType(v))
	}
	return volumesOut, warnings, nil
}

func populateImageFilterByParents(ancestorMap map[image.ID]bool, imageID image.ID, getChildren func(image.ID) []image.ID) {
	if !ancestorMap[imageID] {
		for _, id := range getChildren(imageID) {
			populateImageFilterByParents(ancestorMap, id, getChildren)
		}
		ancestorMap[imageID] = true
	}
}