package docker

import (
	"context"
	"encoding/json"
	"fmt"
	"io"
	"path/filepath"
	"regexp"
	"sort"
	"strconv"
	"strings"
	"time"

	"github.com/docker/docker/api/types"
	"github.com/docker/docker/api/types/container"
	"github.com/docker/docker/api/types/events"
	"github.com/docker/docker/api/types/filters"
	"github.com/docker/docker/client"

	log "github.com/sirupsen/logrus"
)

type StdType int

const (
	UNKNOWN StdType = 1 << iota
	STDOUT
	STDERR
)
const STDALL = STDOUT | STDERR

func (s StdType) String() string {
	switch s {
	case STDOUT:
		return "stdout"
	case STDERR:
		return "stderr"
	case STDALL:
		return "all"
	default:
		return "unknown"
	}
}

type DockerCLI interface {
	ContainerList(context.Context, types.ContainerListOptions) ([]types.Container, error)
	ContainerLogs(context.Context, string, types.ContainerLogsOptions) (io.ReadCloser, error)
	Events(context.Context, types.EventsOptions) (<-chan events.Message, <-chan error)
	ContainerInspect(ctx context.Context, containerID string) (types.ContainerJSON, error)
	ContainerStats(ctx context.Context, containerID string, stream bool) (types.ContainerStats, error)
	Ping(ctx context.Context) (types.Ping, error)
	ContainerStart(ctx context.Context, containerID string, options types.ContainerStartOptions) error
	ContainerStop(ctx context.Context, containerID string, options container.StopOptions) error
	ContainerRestart(ctx context.Context, containerID string, options container.StopOptions) error
}

type Client struct {
	cli     DockerCLI
	filters filters.Args
	host    *Host
}

func NewClient(cli DockerCLI, filters filters.Args, host *Host) *Client {
	return &Client{cli, filters, host}
}

// NewClientWithFilters creates a new instance of Client with docker filters
func NewClientWithFilters(f map[string][]string) (*Client, error) {
	filterArgs := filters.NewArgs()
	for key, values := range f {
		for _, value := range values {
			filterArgs.Add(key, value)
		}
	}

	log.Debugf("filterArgs = %v", filterArgs)

	cli, err := client.NewClientWithOpts(client.FromEnv, client.WithAPIVersionNegotiation())

	if err != nil {
		return nil, err
	}

	return NewClient(cli, filterArgs, &Host{Name: "localhost", ID: "localhost"}), nil
}

func NewClientWithTlsAndFilter(f map[string][]string, host Host) (*Client, error) {
	filterArgs := filters.NewArgs()
	for key, values := range f {
		for _, value := range values {
			filterArgs.Add(key, value)
		}
	}

	log.Debugf("filterArgs = %v", filterArgs)

	if host.URL.Scheme != "tcp" {
		log.Fatal("Only tcp scheme is supported")
	}

	opts := []client.Opt{
		client.WithHost(host.URL.String()),
	}

	if host.ValidCerts {
		log.Debugf("Using TLS client config with certs at: %s", filepath.Dir(host.CertPath))
		opts = append(opts, client.WithTLSClientConfig(host.CACertPath, host.CertPath, host.KeyPath))
	} else {
		log.Debugf("No valid certs found, using plain TCP")
	}

	opts = append(opts, client.WithAPIVersionNegotiation())

	cli, err := client.NewClientWithOpts(opts...)

	if err != nil {
		return nil, err
	}

	return NewClient(cli, filterArgs, &host), nil
}

func (d *Client) FindContainer(id string) (Container, error) {
	var container Container
	containers, err := d.ListContainers()
	if err != nil {
		return container, err
	}

	found := false
	for _, c := range containers {
		if c.ID == id {
			container = c
			found = true
			break
		}
	}
	if !found {
		return container, fmt.Errorf("unable to find container with id: %s", id)
	}

	if json, err := d.cli.ContainerInspect(context.Background(), container.ID); err == nil {
		container.Tty = json.Config.Tty
	} else {
		return container, err
	}

	return container, nil
}

func (d *Client) ContainerActions(action string, containerID string) error {
	switch action {
	case "start":
		return d.cli.ContainerStart(context.Background(), containerID, types.ContainerStartOptions{})
	case "stop":
		return d.cli.ContainerStop(context.Background(), containerID, container.StopOptions{})
	case "restart":
		return d.cli.ContainerRestart(context.Background(), containerID, container.StopOptions{})
	default:
		return fmt.Errorf("unknown action: %s", action)
	}
}

func (d *Client) ListContainers() ([]Container, error) {
	containerListOptions := types.ContainerListOptions{
		Filters: d.filters,
		All:     true,
	}
	list, err := d.cli.ContainerList(context.Background(), containerListOptions)
	if err != nil {
		return nil, err
	}

	var containers = make([]Container, 0, len(list))
	for _, c := range list {
		name := "no name"
		if len(c.Names) > 0 {
			name = strings.TrimPrefix(c.Names[0], "/")
		}
		container := Container{
			ID:      c.ID[:12],
			Names:   c.Names,
			Name:    name,
			Image:   c.Image,
			ImageID: c.ImageID,
			Command: c.Command,
			Created: c.Created,
			State:   c.State,
			Status:  c.Status,
			Host:    d.host.ID,
			Health:  findBetweenParentheses(c.Status),
			Labels:  c.Labels,
		}
		containers = append(containers, container)
	}

	sort.Slice(containers, func(i, j int) bool {
		return strings.ToLower(containers[i].Name) < strings.ToLower(containers[j].Name)
	})

	return containers, nil
}

func (d *Client) ContainerStats(ctx context.Context, id string, stats chan<- ContainerStat) error {
	response, err := d.cli.ContainerStats(ctx, id, true)

	if err != nil {
		return err
	}

	go func() {
		log.Debugf("starting to stream stats for: %s", id)
		defer response.Body.Close()
		decoder := json.NewDecoder(response.Body)
		var v *types.StatsJSON
		for {
			if err := decoder.Decode(&v); err != nil {
				if err == context.Canceled || err == io.EOF {
					log.Debugf("stopping stats streaming for container %s", id)
					return
				}
				log.Errorf("decoder for stats api returned an unknown error %v", err)
			}

			var (
				memPercent, cpuPercent float64
				mem, memLimit          float64
				previousCPU            uint64
				previousSystem         uint64
			)
			daemonOSType := response.OSType

			if daemonOSType != "windows" {
				previousCPU = v.PreCPUStats.CPUUsage.TotalUsage
				previousSystem = v.PreCPUStats.SystemUsage
				cpuPercent = calculateCPUPercentUnix(previousCPU, previousSystem, v)
				mem = calculateMemUsageUnixNoCache(v.MemoryStats)
				memLimit = float64(v.MemoryStats.Limit)
				memPercent = calculateMemPercentUnixNoCache(memLimit, mem)
			} else {
				cpuPercent = calculateCPUPercentWindows(v)
				mem = float64(v.MemoryStats.PrivateWorkingSet)
			}

			log.Tracef("containerId = %s, cpuPercent = %f, memPercent = %f, memUsage = %f, daemonOSType = %s", id, cpuPercent, memPercent, mem, daemonOSType)

			if cpuPercent > 0 || mem > 0 {
				select {
				case <-ctx.Done():
					return
				case stats <- ContainerStat{
					ID:            id,
					CPUPercent:    cpuPercent,
					MemoryPercent: memPercent,
					MemoryUsage:   mem,
				}:
				}
			}
		}
	}()

	return nil
}

func (d *Client) ContainerLogs(ctx context.Context, id string, since string, stdType StdType) (io.ReadCloser, error) {
	log.WithField("id", id).WithField("since", since).WithField("stdType", stdType).Debug("streaming logs for container")

	if since != "" {
		if millis, err := strconv.ParseInt(since, 10, 64); err == nil {
			since = time.UnixMicro(millis).Add(time.Millisecond).Format(time.RFC3339Nano)
		} else {
			log.WithError(err).Debug("unable to parse since")
		}
	}

	options := types.ContainerLogsOptions{
		ShowStdout: stdType&STDOUT != 0,
		ShowStderr: stdType&STDERR != 0,
		Follow:     true,
		Tail:       "300",
		Timestamps: true,
		Since:      since,
	}

	reader, err := d.cli.ContainerLogs(ctx, id, options)
	if err != nil {
		return nil, err
	}

	return reader, nil
}

func (d *Client) Events(ctx context.Context, messages chan<- ContainerEvent) <-chan error {
	dockerMessages, errors := d.cli.Events(ctx, types.EventsOptions{})

	go func() {

		for {
			select {
			case <-ctx.Done():
				return
			case message, ok := <-dockerMessages:
				if !ok {
					return
				}

				if message.Type == "container" && len(message.Actor.ID) > 0 {
					messages <- ContainerEvent{
						ActorID: message.Actor.ID[:12],
						Name:    string(message.Action),
						Host:    d.host.ID,
					}
				}
			}
		}
	}()

	return errors
}

func (d *Client) ContainerLogsBetweenDates(ctx context.Context, id string, from time.Time, to time.Time, stdType StdType) (io.ReadCloser, error) {
	options := types.ContainerLogsOptions{
		ShowStdout: stdType&STDOUT != 0,
		ShowStderr: stdType&STDERR != 0,
		Timestamps: true,
		Since:      from.Format(time.RFC3339),
		Until:      to.Format(time.RFC3339),
	}

	log.Debugf("fetching logs from Docker with option: %+v", options)

	reader, err := d.cli.ContainerLogs(ctx, id, options)
	if err != nil {
		return nil, err
	}

	return reader, nil
}

func (d *Client) Ping(ctx context.Context) (types.Ping, error) {
	return d.cli.Ping(ctx)
}

func (d *Client) Host() *Host {
	return d.host
}

var PARENTHESIS_RE = regexp.MustCompile(`\(([a-zA-Z]+)\)`)

func findBetweenParentheses(s string) string {
	if results := PARENTHESIS_RE.FindStringSubmatch(s); results != nil {
		return results[1]
	}
	return ""
}