/*
Copyright (c) 2019-2021 Digital Energy Cloud Solutions LLC. All Rights Reserved.
Author: Sergey Shubin, <sergey.shubin@digitalenergy.online>, <svs1370@gmail.com>

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 decort

import (

	"encoding/json"
	"fmt"
	// "hash/fnv"
	log "github.com/sirupsen/logrus" 
	// "net/url"

	"github.com/hashicorp/terraform-plugin-sdk/helper/schema"
	"github.com/hashicorp/terraform-plugin-sdk/helper/validation"
)


func flattenPfw(d *schema.ResourceData, pfwFacts string) error {
	// NOTE: this function modifies ResourceData argument - as such it should never be called
	// from resourcePfwExists(...) method
	pfwRecord := ComputePfwListResp{}
	err := json.Unmarshal([]byte(pfwFacts), &pfwRecord)
	if err != nil {
		return err
	}

	log.Debugf("flattenPfw: decoded %d PFW rules for compute ID %s on ViNS ID %d",
	           len(pfwRecord.Rules), pfwRecord.Header.VinsID, pfwRecord.Header.VinsID)

	/*
	Here it gets a little bit interesting. 
	Unlike compute or disk, port forwaring rules are NOT represented by any cloud 
	platform resource, which might have had a unique ID. They are just a subset of
	rules in the list maintained by the corresponding ViNS instance. However, 
	Terraform needs a unique ID for each resource it manages so that it could be 
	stored in the state file and retrieved for use.

	Therefore we need to make up an ID and supply it to Terraform in a standard
	way (i.e. by calling d.SetId(...)).

	Fortunately, a combination of Compute ID and ViNS ID with GW VNF, where this
	compute is plugged in, makes a unique string, so we use it as an ID for
	the PFW ruleset.

	The following few lines are legacy from the first attempt to make an ID
	as a hash of concatenated Compute ID & ViNS ID, but it did not work as
	expected for a number of reasons, which explanation is not a primary
	intent of the comment in the source code.

	combo := fmt.Sprintf("%d:%d", compId.(int), pfwRecord.ViNS.VinsID)
	hasher := fnv.New32a()
	hasher.Write([]byte(combo))
	d.SetId(fmt.Sprintf("%d", hasher.Sum32()))
	*/
	// set ID of this PFW rule set as "compute_id:vins_id"
	d.SetId(fmt.Sprintf("%d:%d", pfwRecord.Header.ComputeID, pfwRecord.Header.VinsID))
	log.Debugf("flattenPfw: PFW rule set ID %s", d.Id())
	d.Set("compute_id", pfwRecord.Header.ComputeID)
	d.Set("vins_id", pfwRecord.Header.VinsID)

	pfwRulesList := []interface{}{}
	for _, runner := range pfwRecord.Rules {
		rule := map[string]interface{}{
			"pub_port_start": runner.PublicPortStart,
			"pub_port_end":   runner.PublicPortEnd,
			"local_port":     runner.LocalPort,
			"proto":          runner.Protocol,
			"rule_id":        runner.ID,
		}
		pfwRulesList = append(pfwRulesList, rule) 
	}
	if err = d.Set("rule", pfwRulesList); err != nil {
		return err
	}

	return nil
}

func dataSourcePfwRead(d *schema.ResourceData, m interface{}) error {
	pfwFacts, err := utilityPfwCheckPresence(d, m)
	if pfwFacts == "" {
		// if empty string is returned from dataSourcePfwRead then we got no
		// PFW rules. It could also be because there was some error, which
		// is indicated by non-nil err value
		d.SetId("") // ensure ID is empty in this case anyway
		return err
	}

	return flattenPfw(d, pfwFacts)
}

func dataSourcePfw() *schema.Resource {
	return &schema.Resource{
		SchemaVersion: 1,

		Read: dataSourcePfwRead,

		Timeouts: &schema.ResourceTimeout{
			Read:    &Timeout30s,
			Default: &Timeout60s,
		},
		
		Schema: map[string]*schema.Schema{
			"compute_id": {
				Type:         schema.TypeInt,
				Required:     true,
				ValidateFunc: validation.IntAtLeast(1),
				Description:  "ID of the compute instance to configure port forwarding rules for.",
			},

			"vins_id": {
				Type:         schema.TypeInt,
				Required:     true,
				ValidateFunc: validation.IntAtLeast(1),
				Description:  "ID of the ViNS to configure port forwarding rules on. Compute must be already plugged into this ViNS and ViNS must have external network connection.",
			},

			// TODO: consider making "rule" attribute Required with MinItems = 1
			"rule": {
				Type:         schema.TypeSet,
				Optional:     true,
				Elem:         &schema.Resource{
					Schema: rulesSubresourceSchemaMake(),
				},
				Description:  "Port forwarding rule. You may specify several rules, one in each such block.",
			},
		},
	}
}