/*
Copyright (c) 2018 VMware, Inc. All Rights Reserved.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

package library

import (
	"context"
	"net/http"
	"time"

	"github.com/vmware/govmomi/vapi/internal"
	"github.com/vmware/govmomi/vapi/rest"
)

// Session is used to create an initial update or download session
type Session struct {
	ClientProgress            int64                    `json:"client_progress,omitempty"`
	ErrorMessage              *rest.LocalizableMessage `json:"error_message,omitempty"`
	ExpirationTime            *time.Time               `json:"expiration_time,omitempty"`
	ID                        string                   `json:"id,omitempty"`
	LibraryItemContentVersion string                   `json:"library_item_content_version,omitempty"`
	LibraryItemID             string                   `json:"library_item_id,omitempty"`
	State                     string                   `json:"state,omitempty"`
}

// CreateLibraryItemUpdateSession creates a new library item
func (c *Manager) CreateLibraryItemUpdateSession(ctx context.Context, session Session) (string, error) {
	url := c.Resource(internal.LibraryItemUpdateSession)
	spec := struct {
		CreateSpec Session `json:"create_spec"`
	}{session}
	var res string
	return res, c.Do(ctx, url.Request(http.MethodPost, spec), &res)
}

// GetLibraryItemUpdateSession gets the update session information with status
func (c *Manager) GetLibraryItemUpdateSession(ctx context.Context, id string) (*Session, error) {
	url := c.Resource(internal.LibraryItemUpdateSession).WithID(id)
	var res Session
	return &res, c.Do(ctx, url.Request(http.MethodGet), &res)
}

// ListLibraryItemUpdateSession gets the list of update sessions
func (c *Manager) ListLibraryItemUpdateSession(ctx context.Context) ([]string, error) {
	url := c.Resource(internal.LibraryItemUpdateSession)
	var res []string
	return res, c.Do(ctx, url.Request(http.MethodGet), &res)
}

// CancelLibraryItemUpdateSession cancels an update session
func (c *Manager) CancelLibraryItemUpdateSession(ctx context.Context, id string) error {
	url := c.Resource(internal.LibraryItemUpdateSession).WithID(id).WithAction("cancel")
	return c.Do(ctx, url.Request(http.MethodPost), nil)
}

// CompleteLibraryItemUpdateSession completes an update session
func (c *Manager) CompleteLibraryItemUpdateSession(ctx context.Context, id string) error {
	url := c.Resource(internal.LibraryItemUpdateSession).WithID(id).WithAction("complete")
	return c.Do(ctx, url.Request(http.MethodPost), nil)
}

// DeleteLibraryItemUpdateSession deletes an update session
func (c *Manager) DeleteLibraryItemUpdateSession(ctx context.Context, id string) error {
	url := c.Resource(internal.LibraryItemUpdateSession).WithID(id)
	return c.Do(ctx, url.Request(http.MethodDelete), nil)
}

// FailLibraryItemUpdateSession fails an update session
func (c *Manager) FailLibraryItemUpdateSession(ctx context.Context, id string) error {
	url := c.Resource(internal.LibraryItemUpdateSession).WithID(id).WithAction("fail")
	return c.Do(ctx, url.Request(http.MethodPost), nil)
}

// KeepAliveLibraryItemUpdateSession keeps an inactive update session alive.
func (c *Manager) KeepAliveLibraryItemUpdateSession(ctx context.Context, id string) error {
	url := c.Resource(internal.LibraryItemUpdateSession).WithID(id).WithAction("keep-alive")
	return c.Do(ctx, url.Request(http.MethodPost), nil)
}

// WaitOnLibraryItemUpdateSession blocks until the update session is no longer
// in the ACTIVE state.
func (c *Manager) WaitOnLibraryItemUpdateSession(
	ctx context.Context, sessionID string,
	interval time.Duration, intervalCallback func()) error {

	// Wait until the upload operation is complete to return.
	for {
		session, err := c.GetLibraryItemUpdateSession(ctx, sessionID)
		if err != nil {
			return err
		}

		if session.State != "ACTIVE" {
			if session.State == "ERROR" {
				return session.ErrorMessage
			}
			return nil
		}
		time.Sleep(interval)
		if intervalCallback != nil {
			intervalCallback()
		}
	}
}

// CreateLibraryItemDownloadSession creates a new library item
func (c *Manager) CreateLibraryItemDownloadSession(ctx context.Context, session Session) (string, error) {
	url := c.Resource(internal.LibraryItemDownloadSession)
	spec := struct {
		CreateSpec Session `json:"create_spec"`
	}{session}
	var res string
	return res, c.Do(ctx, url.Request(http.MethodPost, spec), &res)
}

// GetLibraryItemDownloadSession gets the download session information with status
func (c *Manager) GetLibraryItemDownloadSession(ctx context.Context, id string) (*Session, error) {
	url := c.Resource(internal.LibraryItemDownloadSession).WithID(id)
	var res Session
	return &res, c.Do(ctx, url.Request(http.MethodGet), &res)
}

// ListLibraryItemDownloadSession gets the list of download sessions
func (c *Manager) ListLibraryItemDownloadSession(ctx context.Context) ([]string, error) {
	url := c.Resource(internal.LibraryItemDownloadSession)
	var res []string
	return res, c.Do(ctx, url.Request(http.MethodGet), &res)
}

// CancelLibraryItemDownloadSession cancels an download session
func (c *Manager) CancelLibraryItemDownloadSession(ctx context.Context, id string) error {
	url := c.Resource(internal.LibraryItemDownloadSession).WithID(id).WithAction("cancel")
	return c.Do(ctx, url.Request(http.MethodPost), nil)
}

// DeleteLibraryItemDownloadSession deletes an download session
func (c *Manager) DeleteLibraryItemDownloadSession(ctx context.Context, id string) error {
	url := c.Resource(internal.LibraryItemDownloadSession).WithID(id)
	return c.Do(ctx, url.Request(http.MethodDelete), nil)
}

// FailLibraryItemDownloadSession fails an download session
func (c *Manager) FailLibraryItemDownloadSession(ctx context.Context, id string) error {
	url := c.Resource(internal.LibraryItemDownloadSession).WithID(id).WithAction("fail")
	return c.Do(ctx, url.Request(http.MethodPost), nil)
}

// KeepAliveLibraryItemDownloadSession keeps an inactive download session alive.
func (c *Manager) KeepAliveLibraryItemDownloadSession(ctx context.Context, id string) error {
	url := c.Resource(internal.LibraryItemDownloadSession).WithID(id).WithAction("keep-alive")
	return c.Do(ctx, url.Request(http.MethodPost), nil)
}