package remote

import (
	"context"
	"encoding/json"
	"fmt"
	"strconv"
	"sync"

	"github.com/pterodactyl/wings/api"
	"golang.org/x/sync/errgroup"
)

const (
	ProcessStopCommand    = "command"
	ProcessStopSignal     = "signal"
	ProcessStopNativeStop = "stop"
)

// ServerConfigurationResponse holds the server configuration data returned from
// the Panel. When a server process is started, Wings communicates with the
// Panel to fetch the latest build information as well as get all of the details
// needed to parse the given Egg.
//
// This means we do not need to hit Wings each time part of the server is
// updated, and the Panel serves as the source of truth at all times. This also
// means if a configuration is accidentally wiped on Wings we can self-recover
// without too much hassle, so long as Wings is aware of what servers should
// exist on it.
type ServerConfigurationResponse struct {
	Settings             json.RawMessage           `json:"settings"`
	ProcessConfiguration *api.ProcessConfiguration `json:"process_configuration"`
}

// InstallationScript defines installation script information for a server
// process. This is used when a server is installed for the first time, and when
// a server is marked for re-installation.
type InstallationScript struct {
	ContainerImage string `json:"container_image"`
	Entrypoint     string `json:"entrypoint"`
	Script         string `json:"script"`
}

// RawServerData is a raw response from the API for a server.
type RawServerData struct {
	Uuid                 string          `json:"uuid"`
	Settings             json.RawMessage `json:"settings"`
	ProcessConfiguration json.RawMessage `json:"process_configuration"`
}

// GetServers returns all of the servers that are present on the Panel making
// parallel API calls to the endpoint if more than one page of servers is
// returned.
func (c *client) GetServers(ctx context.Context, limit int) ([]RawServerData, error) {
	servers, meta, err := c.getServersPaged(ctx, 0, limit)
	if err != nil {
		return nil, err
	}

	var mu sync.Mutex
	if meta.LastPage > 1 {
		g, ctx := errgroup.WithContext(ctx)
		for page := meta.CurrentPage + 1; page <= meta.LastPage; page++ {
			page := page
			g.Go(func() error {
				ps, _, err := c.getServersPaged(ctx, int(page), limit)
				if err != nil {
					return err
				}
				mu.Lock()
				servers = append(servers, ps...)
				mu.Unlock()
				return nil
			})
		}
		if err := g.Wait(); err != nil {
			return nil, err
		}
	}

	return servers, nil
}

func (c *client) GetServerConfiguration(ctx context.Context, uuid string) (ServerConfigurationResponse, error) {
	var config ServerConfigurationResponse
	res, err := c.get(ctx, fmt.Sprintf("/servers/%s", uuid), nil)
	if err != nil {
		return config, err
	}
	defer res.Body.Close()

	if res.HasError() {
		return config, err
	}

	err = res.BindJSON(&config)
	return config, err
}

func (c *client) GetInstallationScript(ctx context.Context, uuid string) (InstallationScript, error) {
	res, err := c.get(ctx, fmt.Sprintf("/servers/%s/install", uuid), nil)
	if err != nil {
		return InstallationScript{}, err
	}
	defer res.Body.Close()

	if res.HasError() {
		return InstallationScript{}, err
	}

	var config InstallationScript
	err = res.BindJSON(&config)
	return config, err
}

func (c *client) SetInstallationStatus(ctx context.Context, uuid string, successful bool) error {
	resp, err := c.post(ctx, fmt.Sprintf("/servers/%s/install", uuid), d{"successful": successful})
	if err != nil {
		return err
	}
	defer resp.Body.Close()
	return resp.Error()
}

func (c *client) SetArchiveStatus(ctx context.Context, uuid string, successful bool) error {
	resp, err := c.post(ctx, fmt.Sprintf("/servers/%s/archive", uuid), d{"successful": successful})
	if err != nil {
		return err
	}
	defer resp.Body.Close()
	return resp.Error()
}

func (c *client) SetTransferStatus(ctx context.Context, uuid string, successful bool) error {
	state := "failure"
	if successful {
		state = "success"
	}
	resp, err := c.get(ctx, fmt.Sprintf("/servers/%s/transfer/%s", uuid, state), nil)
	if err != nil {
		return err
	}
	defer resp.Body.Close()
	return resp.Error()
}

// getServersPaged returns a subset of servers from the Panel API using the
// pagination query parameters.
func (c *client) getServersPaged(ctx context.Context, page, limit int) ([]RawServerData, api.Pagination, error) {
	res, err := c.get(ctx, "/servers", q{
		"page":     strconv.Itoa(page),
		"per_page": strconv.Itoa(limit),
	})
	if err != nil {
		return nil, api.Pagination{}, err
	}
	defer res.Body.Close()

	if res.HasError() {
		return nil, api.Pagination{}, res.Error()
	}

	var r struct {
		Data []RawServerData `json:"data"`
		Meta api.Pagination      `json:"meta"`
	}
	if err := res.BindJSON(&r); err != nil {
		return nil, api.Pagination{}, err
	}

	return r.Data, r.Meta, nil
}