package daemon

import (
	"fmt"
	"path/filepath"
	"regexp"
	"time"

	"github.com/docker/docker/container"
	"github.com/docker/docker/daemon/network"
	"github.com/docker/docker/errors"
	"github.com/docker/docker/image"
	"github.com/docker/docker/pkg/signal"
	"github.com/docker/docker/pkg/system"
	"github.com/docker/docker/pkg/truncindex"
	containertypes "github.com/docker/engine-api/types/container"
	"github.com/docker/engine-api/types/strslice"
	"github.com/docker/go-connections/nat"
)

// GetContainer looks for a container using the provided information, which could be
// one of the following inputs from the caller:
//  - A full container ID, which will exact match a container in daemon's list
//  - A container name, which will only exact match via the GetByName() function
//  - A partial container ID prefix (e.g. short ID) of any length that is
//    unique enough to only return a single container object
//  If none of these searches succeed, an error is returned
func (daemon *Daemon) GetContainer(prefixOrName string) (*container.Container, error) {
	if len(prefixOrName) == 0 {
		return nil, errors.NewBadRequestError(fmt.Errorf("No container name or ID supplied"))
	}

	if containerByID := daemon.containers.Get(prefixOrName); containerByID != nil {
		// prefix is an exact match to a full container ID
		return containerByID, nil
	}

	// GetByName will match only an exact name provided; we ignore errors
	if containerByName, _ := daemon.GetByName(prefixOrName); containerByName != nil {
		// prefix is an exact match to a full container Name
		return containerByName, nil
	}

	containerID, indexError := daemon.idIndex.Get(prefixOrName)
	if indexError != nil {
		// When truncindex defines an error type, use that instead
		if indexError == truncindex.ErrNotExist {
			err := fmt.Errorf("No such container: %s", prefixOrName)
			return nil, errors.NewRequestNotFoundError(err)
		}
		return nil, indexError
	}
	return daemon.containers.Get(containerID), nil
}

// Exists returns a true if a container of the specified ID or name exists,
// false otherwise.
func (daemon *Daemon) Exists(id string) bool {
	c, _ := daemon.GetContainer(id)
	return c != nil
}

// IsPaused returns a bool indicating if the specified container is paused.
func (daemon *Daemon) IsPaused(id string) bool {
	c, _ := daemon.GetContainer(id)
	return c.State.IsPaused()
}

func (daemon *Daemon) containerRoot(id string) string {
	return filepath.Join(daemon.repository, id)
}

// Load reads the contents of a container from disk
// This is typically done at startup.
func (daemon *Daemon) load(id string) (*container.Container, error) {
	container := daemon.newBaseContainer(id)

	if err := container.FromDisk(); err != nil {
		return nil, err
	}

	if container.ID != id {
		return container, fmt.Errorf("Container %s is stored at %s", container.ID, id)
	}

	return container, nil
}

// Register makes a container object usable by the daemon as <container.ID>
func (daemon *Daemon) Register(c *container.Container) error {
	// Attach to stdout and stderr
	if c.Config.OpenStdin {
		c.NewInputPipes()
	} else {
		c.NewNopInputPipe()
	}

	daemon.containers.Add(c.ID, c)
	daemon.idIndex.Add(c.ID)

	return nil
}

func (daemon *Daemon) newContainer(name string, config *containertypes.Config, imgID image.ID) (*container.Container, error) {
	var (
		id             string
		err            error
		noExplicitName = name == ""
	)
	id, name, err = daemon.generateIDAndName(name)
	if err != nil {
		return nil, err
	}

	daemon.generateHostname(id, config)
	entrypoint, args := daemon.getEntrypointAndArgs(config.Entrypoint, config.Cmd)

	base := daemon.newBaseContainer(id)
	base.Created = time.Now().UTC()
	base.Path = entrypoint
	base.Args = args //FIXME: de-duplicate from config
	base.Config = config
	base.HostConfig = &containertypes.HostConfig{}
	base.ImageID = imgID
	base.NetworkSettings = &network.Settings{IsAnonymousEndpoint: noExplicitName}
	base.Name = name
	base.Driver = daemon.GraphDriverName()

	return base, err
}

// GetByName returns a container given a name.
func (daemon *Daemon) GetByName(name string) (*container.Container, error) {
	if len(name) == 0 {
		return nil, fmt.Errorf("No container name supplied")
	}
	fullName := name
	if name[0] != '/' {
		fullName = "/" + name
	}
	id, err := daemon.nameIndex.Get(fullName)
	if err != nil {
		return nil, fmt.Errorf("Could not find entity for %s", name)
	}
	e := daemon.containers.Get(id)
	if e == nil {
		return nil, fmt.Errorf("Could not find container for entity id %s", id)
	}
	return e, nil
}

// newBaseContainer creates a new container with its initial
// configuration based on the root storage from the daemon.
func (daemon *Daemon) newBaseContainer(id string) *container.Container {
	return container.NewBaseContainer(id, daemon.containerRoot(id))
}

func (daemon *Daemon) getEntrypointAndArgs(configEntrypoint strslice.StrSlice, configCmd strslice.StrSlice) (string, []string) {
	if len(configEntrypoint) != 0 {
		return configEntrypoint[0], append(configEntrypoint[1:], configCmd...)
	}
	return configCmd[0], configCmd[1:]
}

func (daemon *Daemon) generateHostname(id string, config *containertypes.Config) {
	// Generate default hostname
	if config.Hostname == "" {
		config.Hostname = id[:12]
	}
}

func (daemon *Daemon) setSecurityOptions(container *container.Container, hostConfig *containertypes.HostConfig) error {
	container.Lock()
	defer container.Unlock()
	return parseSecurityOpt(container, hostConfig)
}

func (daemon *Daemon) setHostConfig(container *container.Container, hostConfig *containertypes.HostConfig) error {
	// Do not lock while creating volumes since this could be calling out to external plugins
	// Don't want to block other actions, like `docker ps` because we're waiting on an external plugin
	if err := daemon.registerMountPoints(container, hostConfig); err != nil {
		return err
	}

	container.Lock()
	defer container.Unlock()

	// Register any links from the host config before starting the container
	if err := daemon.registerLinks(container, hostConfig); err != nil {
		return err
	}

	// make sure links is not nil
	// this ensures that on the next daemon restart we don't try to migrate from legacy sqlite links
	if hostConfig.Links == nil {
		hostConfig.Links = []string{}
	}

	container.HostConfig = hostConfig
	return container.ToDisk()
}

// verifyContainerSettings performs validation of the hostconfig and config
// structures.
func (daemon *Daemon) verifyContainerSettings(hostConfig *containertypes.HostConfig, config *containertypes.Config, update bool) ([]string, error) {

	// First perform verification of settings common across all platforms.
	if config != nil {
		if config.WorkingDir != "" {
			config.WorkingDir = filepath.FromSlash(config.WorkingDir) // Ensure in platform semantics
			if !system.IsAbs(config.WorkingDir) {
				return nil, fmt.Errorf("The working directory '%s' is invalid. It needs to be an absolute path", config.WorkingDir)
			}
		}

		if len(config.StopSignal) > 0 {
			_, err := signal.ParseSignal(config.StopSignal)
			if err != nil {
				return nil, err
			}
		}

		// Validate if the given hostname is RFC 1123 (https://tools.ietf.org/html/rfc1123) compliant.
		if len(config.Hostname) > 0 {
			// RFC1123 specifies that 63 bytes is the maximium length
			// Windows has the limitation of 63 bytes in length
			// Linux hostname is limited to HOST_NAME_MAX=64, not not including the terminating null byte.
			// We limit the length to 63 bytes here to match RFC1035 and RFC1123.
			matched, _ := regexp.MatchString("^(([[:alnum:]]|[[:alnum:]][[:alnum:]\\-]*[[:alnum:]])\\.)*([[:alnum:]]|[[:alnum:]][[:alnum:]\\-]*[[:alnum:]])$", config.Hostname)
			if len(config.Hostname) > 63 || !matched {
				return nil, fmt.Errorf("invalid hostname format: %s", config.Hostname)
			}
		}
	}

	if hostConfig == nil {
		return nil, nil
	}

	for port := range hostConfig.PortBindings {
		_, portStr := nat.SplitProtoPort(string(port))
		if _, err := nat.ParsePort(portStr); err != nil {
			return nil, fmt.Errorf("Invalid port specification: %q", portStr)
		}
		for _, pb := range hostConfig.PortBindings[port] {
			_, err := nat.NewPort(nat.SplitProtoPort(pb.HostPort))
			if err != nil {
				return nil, fmt.Errorf("Invalid port specification: %q", pb.HostPort)
			}
		}
	}

	// Now do platform-specific verification
	return verifyPlatformContainerSettings(daemon, hostConfig, config, update)
}