package daemon

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

	"github.com/Sirupsen/logrus"
	"github.com/docker/docker/api/types"
	"github.com/docker/docker/image"
	"github.com/docker/docker/pkg/graphdb"
	"github.com/docker/docker/pkg/nat"
	"github.com/docker/docker/pkg/parsers/filters"
)

// 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, *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 {
	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[string]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
	// beforeContainer is a filter to ignore containers that appear before the one given
	beforeContainer *Container
	// sinceContainer is a filter to stop the filtering when the iterator arrive to the given container
	sinceContainer *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) {
	var 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, 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
	if i, ok := psFilters["exited"]; ok {
		for _, value := range i {
			code, err := strconv.Atoi(value)
			if err != nil {
				return nil, err
			}
			filtExited = append(filtExited, code)
		}
	}

	if i, ok := psFilters["status"]; ok {
		for _, value := range i {
			if !isValidStateString(value) {
				return nil, errors.New("Unrecognised filter value for status")
			}
			if value == "exited" || value == "created" {
				config.All = true
			}
		}
	}

	imagesFilter := map[string]bool{}
	var ancestorFilter bool
	if ancestors, ok := psFilters["ancestor"]; ok {
		ancestorFilter = true
		byParents := daemon.Graph().ByParent()
		// The idea is to walk the graph down the most "efficient" way.
		for _, ancestor := range ancestors {
			// First, get the imageId of the ancestor filter (yay)
			image, err := daemon.Repositories().LookupImage(ancestor)
			if err != nil {
				logrus.Warnf("Error while looking up for image %v", ancestor)
				continue
			}
			if imagesFilter[ancestor] {
				// Already seen this ancestor, skip it
				continue
			}
			// Then walk down the graph and put the imageIds in imagesFilter
			populateImageFilterByParents(imagesFilter, image.ID, byParents)
		}
	}

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

	var beforeCont, sinceCont *Container
	if config.Before != "" {
		beforeCont, err = daemon.Get(config.Before)
		if err != nil {
			return nil, err
		}
	}

	if config.Since != "" {
		sinceCont, err = daemon.Get(config.Since)
		if err != nil {
			return nil, err
		}
	}

	return &listContext{
		filters:          psFilters,
		ancestorFilter:   ancestorFilter,
		names:            names,
		images:           imagesFilter,
		exitAllowed:      filtExited,
		beforeContainer:  beforeCont,
		sinceContainer:   sinceCont,
		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, 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.beforeContainer == nil && ctx.sinceContainer == 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 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.beforeContainer != nil {
		if container.ID == ctx.beforeContainer.ID {
			ctx.beforeContainer = nil
		}
		return excludeContainer
	}

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

	// Stop interation when the container arrives to the filter container
	if ctx.sinceContainer != nil {
		if container.ID == ctx.sinceContainer.ID {
			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, ctx *listContext) (*types.Container, error) {
	newC := &types.Container{
		ID:    container.ID,
		Names: ctx.names[container.ID],
	}

	img, err := daemon.Repositories().LookupImage(container.Config.Image)
	if err != nil {
		// If the image can no longer be found by its original reference,
		// it makes sense to show the ID instead of a stale reference.
		newC.Image = container.ImageID
	} else if container.ImageID == img.ID {
		newC.Image = container.Config.Image
	} else {
		newC.Image = container.ImageID
	}

	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.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 := container.getSize()
		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, error) {
	var volumesOut []*types.Volume
	volFilters, err := filters.FromParam(filter)
	if err != nil {
		return nil, err
	}

	filterUsed := false
	if i, ok := volFilters["dangling"]; ok {
		if len(i) > 1 {
			return nil, fmt.Errorf("Conflict: cannot use more than 1 value for `dangling` filter")
		}

		filterValue := i[0]
		if strings.ToLower(filterValue) == "true" || filterValue == "1" {
			filterUsed = true
		}
	}

	volumes := daemon.volumes.List()
	for _, v := range volumes {
		if filterUsed && daemon.volumes.Count(v) == 0 {
			continue
		}
		volumesOut = append(volumesOut, volumeToAPIType(v))
	}
	return volumesOut, nil
}

func populateImageFilterByParents(ancestorMap map[string]bool, imageID string, byParents map[string][]*image.Image) {
	if !ancestorMap[imageID] {
		if images, ok := byParents[imageID]; ok {
			for _, image := range images {
				populateImageFilterByParents(ancestorMap, image.ID, byParents)
			}
		}
		ancestorMap[imageID] = true
	}
}