//
// Licensed to the Apache Software Foundation (ASF) under one
// or more contributor license agreements.  See the NOTICE file
// distributed with this work for additional information
// regarding copyright ownership.  The ASF licenses this file
// to you 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 cloudstack

import (
	"encoding/json"
	"fmt"
	"log"
	"regexp"
	"strings"
	"time"

	"github.com/apache/cloudstack-go/v2/cloudstack"
	"github.com/hashicorp/terraform-plugin-sdk/v2/helper/schema"
)

func dataSourceCloudstackNetworkOffering() *schema.Resource {
	return &schema.Resource{
		Read: datasourceCloudStackNetworkOfferingRead,
		Schema: map[string]*schema.Schema{
			"filter": dataSourceFiltersSchema(),

			//Computed values
			"name": {
				Type:     schema.TypeString,
				Computed: true,
			},
			"display_text": {
				Type:     schema.TypeString,
				Computed: true,
			},
			"guest_ip_type": {
				Type:     schema.TypeString,
				Computed: true,
			},
			"traffic_type": {
				Type:     schema.TypeString,
				Computed: true,
			},
			"network_rate": {
				Type:     schema.TypeInt,
				Computed: true,
			},
			"network_mode": {
				Type:     schema.TypeString,
				Computed: true,
			},
			"conserve_mode": {
				Type:     schema.TypeBool,
				Computed: true,
			},
			"enable": {
				Type:     schema.TypeBool,
				Computed: true,
			},
			"for_vpc": {
				Type:     schema.TypeBool,
				Computed: true,
			},
			"for_nsx": {
				Type:     schema.TypeBool,
				Computed: true,
			},
			"specify_vlan": {
				Type:     schema.TypeBool,
				Computed: true,
			},
			"specify_ip_ranges": {
				Type:     schema.TypeBool,
				Computed: true,
			},
			"specify_as_number": {
				Type:     schema.TypeBool,
				Computed: true,
			},
			"internet_protocol": {
				Type:     schema.TypeString,
				Computed: true,
			},
			"routing_mode": {
				Type:     schema.TypeString,
				Computed: true,
			},
			"max_connections": {
				Type:     schema.TypeInt,
				Computed: true,
			},
			"supported_services": {
				Type:     schema.TypeSet,
				Computed: true,
				Elem:     &schema.Schema{Type: schema.TypeString},
			},
			"service_provider_list": {
				Type:     schema.TypeMap,
				Computed: true,
				Elem:     &schema.Schema{Type: schema.TypeString},
			},
		},
	}
}

func datasourceCloudStackNetworkOfferingRead(d *schema.ResourceData, meta interface{}) error {
	cs := meta.(*cloudstack.CloudStackClient)
	p := cs.NetworkOffering.NewListNetworkOfferingsParams()
	csNetworkOfferings, err := cs.NetworkOffering.ListNetworkOfferings(p)

	if err != nil {
		return fmt.Errorf("Failed to list network offerings: %s", err)
	}

	filters := d.Get("filter")
	var networkOfferings []*cloudstack.NetworkOffering

	for _, n := range csNetworkOfferings.NetworkOfferings {
		match, err := applyNetworkOfferingFilters(n, filters.(*schema.Set))
		if err != nil {
			return err
		}
		if match {
			networkOfferings = append(networkOfferings, n)
		}
	}

	if len(networkOfferings) == 0 {
		return fmt.Errorf("No network offering is matching with the specified regex")
	}
	//return the latest network offering from the list of filtered network offerings according
	//to its creation date
	networkOffering, err := latestNetworkOffering(networkOfferings)
	if err != nil {
		return err
	}
	log.Printf("[DEBUG] Selected network offerings: %s\n", networkOffering.Displaytext)

	fullNetworkOffering, _, err := cs.NetworkOffering.GetNetworkOfferingByName(networkOffering.Name)
	if err != nil {
		return fmt.Errorf("Error retrieving full network offering details: %s", err)
	}

	return networkOfferingDescriptionAttributes(d, fullNetworkOffering)
}

func networkOfferingDescriptionAttributes(d *schema.ResourceData, networkOffering *cloudstack.NetworkOffering) error {
	d.SetId(networkOffering.Id)
	d.Set("name", networkOffering.Name)
	d.Set("display_text", networkOffering.Displaytext)
	d.Set("guest_ip_type", networkOffering.Guestiptype)
	d.Set("traffic_type", networkOffering.Traffictype)
	d.Set("network_rate", networkOffering.Networkrate)

	// Only set if CloudStack supports these fields (4.20.0+)
	if networkOffering.Networkmode != "" {
		d.Set("network_mode", networkOffering.Networkmode)
	}

	d.Set("conserve_mode", networkOffering.Conservemode)
	d.Set("enable", networkOffering.State == "Enabled")
	d.Set("for_vpc", networkOffering.Forvpc)
	d.Set("for_nsx", networkOffering.Fornsx)
	d.Set("specify_vlan", networkOffering.Specifyvlan)
	d.Set("specify_ip_ranges", networkOffering.Specifyipranges)
	d.Set("specify_as_number", networkOffering.Specifyasnumber)
	d.Set("internet_protocol", networkOffering.Internetprotocol)

	// Only set if CloudStack supports this field (4.20.0+)
	if networkOffering.Routingmode != "" {
		d.Set("routing_mode", networkOffering.Routingmode)
	}

	if networkOffering.Maxconnections > 0 {
		d.Set("max_connections", networkOffering.Maxconnections)
	}

	// Set supported services
	if len(networkOffering.Service) > 0 {
		services := make([]string, len(networkOffering.Service))
		for i, service := range networkOffering.Service {
			services[i] = service.Name
		}
		d.Set("supported_services", services)
	}

	// Set service provider list
	if len(networkOffering.Service) > 0 {
		serviceProviders := make(map[string]string)
		for _, service := range networkOffering.Service {
			if len(service.Provider) > 0 {
				serviceProviders[service.Name] = service.Provider[0].Name
			}
		}
		d.Set("service_provider_list", serviceProviders)
	}

	return nil
}

func latestNetworkOffering(networkOfferings []*cloudstack.NetworkOffering) (*cloudstack.NetworkOffering, error) {
	var latest time.Time
	var networkOffering *cloudstack.NetworkOffering

	for _, n := range networkOfferings {
		created, err := time.Parse("2006-01-02T15:04:05-0700", n.Created)
		if err != nil {
			return nil, fmt.Errorf("Failed to parse creation date of a network offering: %s", err)
		}

		if created.After(latest) {
			latest = created
			networkOffering = n
		}
	}

	return networkOffering, nil
}

func applyNetworkOfferingFilters(networkOffering *cloudstack.NetworkOffering, filters *schema.Set) (bool, error) {
	var networkOfferingJSON map[string]interface{}
	k, _ := json.Marshal(networkOffering)
	err := json.Unmarshal(k, &networkOfferingJSON)
	if err != nil {
		return false, err
	}

	for _, f := range filters.List() {
		m := f.(map[string]interface{})
		r, err := regexp.Compile(m["value"].(string))
		if err != nil {
			return false, fmt.Errorf("Invalid regex: %s", err)
		}
		updatedName := strings.ReplaceAll(m["name"].(string), "_", "")
		networkOfferingField := networkOfferingJSON[updatedName].(string)
		if !r.MatchString(networkOfferingField) {
			return false, nil
		}

	}
	return true, nil
}