/*
Real-time Online/Offline Charging System (OCS) for Telecom & ISP environments
Copyright (C) ITsysCOM GmbH

This program is free software: you can redistribute it and/or modify
it under the terms of the GNU Affero General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU Affero General Public License for more details.

You should have received a copy of the GNU Affero General Public License
along with this program.  If not, see <https://www.gnu.org/licenses/>
*/

package ips

import (
	"errors"
	"fmt"

	"github.com/cgrates/birpc/context"
	"github.com/cgrates/cgrates/config"
	"github.com/cgrates/cgrates/engine"
	"github.com/cgrates/cgrates/utils"
	"github.com/cgrates/guardian"
)

// V1GetIPAllocationForEvent returns the IPAllocations object matching the event.
func (s *IPService) V1GetIPAllocationForEvent(ctx *context.Context, args *utils.CGREvent, reply *utils.IPAllocations) (err error) {
	if args == nil {
		return utils.NewErrMandatoryIeMissing(utils.Event)
	}
	if missing := utils.MissingStructFields(args, []string{utils.ID, utils.Event}); len(missing) != 0 { //Params missing
		return utils.NewErrMandatoryIeMissing(missing...)
	}

	var allocID string
	if allocID, err = engine.GetStringOpts(ctx, args.Tenant, args.AsDataProvider(), nil, s.fltrs, s.cfg.IPsCfg().Opts.AllocationID,
		utils.OptsIPsAllocationID); err != nil {
		return
	}

	if allocID == utils.EmptyString {
		return utils.NewErrMandatoryIeMissing(utils.AllocationID)
	}
	tnt := args.Tenant
	if tnt == utils.EmptyString {
		tnt = s.cfg.GeneralCfg().DefaultTenant
	}

	// RPC caching
	if config.CgrConfig().CacheCfg().Partitions[utils.CacheRPCResponses].Limit != 0 {
		cacheKey := utils.ConcatenatedKey(utils.IPsV1GetIPAllocationForEvent, utils.ConcatenatedKey(tnt, args.ID))
		refID := guardian.Guardian.GuardIDs("",
			config.CgrConfig().GeneralCfg().LockingTimeout, cacheKey) // RPC caching needs to be atomic
		defer guardian.Guardian.UnguardIDs(refID)
		if itm, has := engine.Cache.Get(utils.CacheRPCResponses, cacheKey); has {
			cachedResp := itm.(*utils.CachedRPCResponse)
			if cachedResp.Error == nil {
				*reply = *cachedResp.Result.(*utils.IPAllocations)
			}
			return cachedResp.Error
		}
		defer engine.Cache.Set(ctx, utils.CacheRPCResponses, cacheKey,
			&utils.CachedRPCResponse{Result: reply, Error: err},
			nil, true, utils.NonTransactional)
	}
	// end of RPC caching

	var allocs *utils.IPAllocations
	if allocs, err = s.matchingIPAllocationsForEvent(ctx, tnt, args, allocID); err != nil {
		return err
	}
	defer allocs.Unlock()
	*reply = *allocs
	return
}

// V1AuthorizeIP checks if it's able to allocate an IP address for the given event.
func (s *IPService) V1AuthorizeIP(ctx *context.Context, args *utils.CGREvent, reply *utils.AllocatedIP) (err error) {
	if args == nil {
		return utils.NewErrMandatoryIeMissing(utils.Event)
	}
	if missing := utils.MissingStructFields(args, []string{utils.ID, utils.Event}); len(missing) != 0 { //Params missing
		return utils.NewErrMandatoryIeMissing(missing...)
	}

	var allocID string
	if allocID, err = engine.GetStringOpts(ctx, args.Tenant, args.AsDataProvider(), nil, s.fltrs,
		s.cfg.IPsCfg().Opts.AllocationID, utils.OptsIPsAllocationID); err != nil {
		return err
	}
	if allocID == utils.EmptyString {
		return utils.NewErrMandatoryIeMissing(utils.AllocationID)
	}

	tnt := args.Tenant
	if tnt == utils.EmptyString {
		tnt = s.cfg.GeneralCfg().DefaultTenant
	}

	// RPC caching
	if config.CgrConfig().CacheCfg().Partitions[utils.CacheRPCResponses].Limit != 0 {
		cacheKey := utils.ConcatenatedKey(utils.IPsV1AuthorizeIP, utils.ConcatenatedKey(tnt, args.ID))
		refID := guardian.Guardian.GuardIDs("",
			config.CgrConfig().GeneralCfg().LockingTimeout, cacheKey) // RPC caching needs to be atomic
		defer guardian.Guardian.UnguardIDs(refID)
		if itm, has := engine.Cache.Get(utils.CacheRPCResponses, cacheKey); has {
			cachedResp := itm.(*utils.CachedRPCResponse)
			if cachedResp.Error == nil {
				*reply = *cachedResp.Result.(*utils.AllocatedIP)
			}
			return cachedResp.Error
		}
		defer engine.Cache.Set(ctx, utils.CacheRPCResponses, cacheKey,
			&utils.CachedRPCResponse{Result: reply, Error: err},
			nil, true, utils.NonTransactional)
	}
	// end of RPC caching

	var allocs *utils.IPAllocations
	if allocs, err = s.matchingIPAllocationsForEvent(ctx, tnt, args, allocID); err != nil {
		return err
	}
	defer allocs.Unlock()

	var poolIDs []string
	if poolIDs, err = filterAndSortPools(ctx, tnt, allocs.Config().Pools, s.fltrs,
		args.AsDataProvider()); err != nil {
		return err
	}

	var allocIP *utils.AllocatedIP
	if allocIP, err = s.allocateFromPools(allocs, allocID, poolIDs, true); err != nil {
		if errors.Is(err, utils.ErrIPAlreadyAllocated) {
			return utils.ErrIPUnauthorized
		}
		return err
	}

	*reply = *allocIP
	return nil
}

// V1AllocateIP allocates an IP address for the given event.
func (s *IPService) V1AllocateIP(ctx *context.Context, args *utils.CGREvent, reply *utils.AllocatedIP) (err error) {
	if args == nil {
		return utils.NewErrMandatoryIeMissing(utils.Event)
	}
	if missing := utils.MissingStructFields(args, []string{utils.ID, utils.Event}); len(missing) != 0 { //Params missing
		return utils.NewErrMandatoryIeMissing(missing...)
	}

	var allocID string
	if allocID, err = engine.GetStringOpts(ctx, args.Tenant, args.AsDataProvider(), nil, s.fltrs, s.cfg.IPsCfg().Opts.AllocationID,
		utils.OptsIPsAllocationID); err != nil {
		return err
	}
	if allocID == utils.EmptyString {
		return utils.NewErrMandatoryIeMissing(utils.AllocationID)
	}

	tnt := args.Tenant
	if tnt == utils.EmptyString {
		tnt = s.cfg.GeneralCfg().DefaultTenant
	}

	// RPC caching
	if config.CgrConfig().CacheCfg().Partitions[utils.CacheRPCResponses].Limit != 0 {
		cacheKey := utils.ConcatenatedKey(utils.IPsV1AllocateIP, utils.ConcatenatedKey(tnt, args.ID))
		refID := guardian.Guardian.GuardIDs("",
			config.CgrConfig().GeneralCfg().LockingTimeout, cacheKey) // RPC caching needs to be atomic
		defer guardian.Guardian.UnguardIDs(refID)
		if itm, has := engine.Cache.Get(utils.CacheRPCResponses, cacheKey); has {
			cachedResp := itm.(*utils.CachedRPCResponse)
			if cachedResp.Error == nil {
				*reply = *cachedResp.Result.(*utils.AllocatedIP)
			}
			return cachedResp.Error
		}
		defer engine.Cache.Set(ctx, utils.CacheRPCResponses, cacheKey,
			&utils.CachedRPCResponse{Result: reply, Error: err},
			nil, true, utils.NonTransactional)
	}
	// end of RPC caching

	var allocs *utils.IPAllocations
	if allocs, err = s.matchingIPAllocationsForEvent(ctx, tnt, args, allocID); err != nil {
		return err
	}
	defer allocs.Unlock()

	var poolIDs []string
	if poolIDs, err = filterAndSortPools(ctx, tnt, allocs.Config().Pools, s.fltrs,
		args.AsDataProvider()); err != nil {
		return err
	}

	var allocIP *utils.AllocatedIP
	if allocIP, err = s.allocateFromPools(allocs, allocID, poolIDs, false); err != nil {
		return err
	}

	// index it for storing
	if err = s.storeMatchedIPAllocations(ctx, allocs); err != nil {
		return err
	}
	*reply = *allocIP
	return nil
}

// V1ReleaseIP releases an allocated IP address for the given event.
func (s *IPService) V1ReleaseIP(ctx *context.Context, args *utils.CGREvent, reply *string) (err error) {
	if args == nil {
		return utils.NewErrMandatoryIeMissing(utils.Event)
	}
	if missing := utils.MissingStructFields(args, []string{utils.ID, utils.Event}); len(missing) != 0 { //Params missing
		return utils.NewErrMandatoryIeMissing(missing...)
	}

	var allocID string
	if allocID, err = engine.GetStringOpts(ctx, args.Tenant, args.AsDataProvider(), nil, s.fltrs, s.cfg.IPsCfg().Opts.AllocationID,
		utils.OptsIPsAllocationID); err != nil {
		return err
	}
	if allocID == utils.EmptyString {
		return utils.NewErrMandatoryIeMissing(utils.AllocationID)
	}

	tnt := args.Tenant
	if tnt == utils.EmptyString {
		tnt = s.cfg.GeneralCfg().DefaultTenant
	}

	// RPC caching
	if config.CgrConfig().CacheCfg().Partitions[utils.CacheRPCResponses].Limit != 0 {
		cacheKey := utils.ConcatenatedKey(utils.IPsV1ReleaseIP, utils.ConcatenatedKey(tnt, args.ID))
		refID := guardian.Guardian.GuardIDs("",
			config.CgrConfig().GeneralCfg().LockingTimeout, cacheKey) // RPC caching needs to be atomic
		defer guardian.Guardian.UnguardIDs(refID)
		if itm, has := engine.Cache.Get(utils.CacheRPCResponses, cacheKey); has {
			cachedResp := itm.(*utils.CachedRPCResponse)
			if cachedResp.Error == nil {
				*reply = *cachedResp.Result.(*string)
			}
			return cachedResp.Error
		}
		defer engine.Cache.Set(ctx, utils.CacheRPCResponses, cacheKey,
			&utils.CachedRPCResponse{Result: reply, Error: err},
			nil, true, utils.NonTransactional)
	}
	// end of RPC caching

	var allocs *utils.IPAllocations
	if allocs, err = s.matchingIPAllocationsForEvent(ctx, tnt, args, allocID); err != nil {
		return err
	}
	defer allocs.Unlock()

	if err = allocs.ReleaseAllocation(allocID); err != nil {
		utils.Logger.Warning(fmt.Sprintf(
			"<%s> failed to remove allocation from IPAllocations with ID %q: %v", utils.IPs, allocs.TenantID(), err))
	}

	// Handle storing
	if err = s.storeMatchedIPAllocations(ctx, allocs); err != nil {
		return err
	}

	*reply = utils.OK
	return nil
}

// V1GetIPAllocations returns all IP allocations for a tenantID.
func (s *IPService) V1GetIPAllocations(ctx *context.Context, arg *utils.TenantIDWithAPIOpts, reply *utils.IPAllocations) error {
	if missing := utils.MissingStructFields(arg, []string{utils.ID}); len(missing) != 0 { //Params missing
		return utils.NewErrMandatoryIeMissing(missing...)
	}
	tnt := arg.Tenant
	if tnt == utils.EmptyString {
		tnt = s.cfg.GeneralCfg().DefaultTenant
	}

	// make sure resource is locked at process level
	lkID := guardian.Guardian.GuardIDs(utils.EmptyString,
		config.CgrConfig().GeneralCfg().LockingTimeout,
		utils.IPAllocationsLockKey(tnt, arg.ID))
	defer guardian.Guardian.UnguardIDs(lkID)

	ip, err := s.dm.GetIPAllocations(ctx, tnt, arg.ID, true, true, utils.NonTransactional, nil)
	if err != nil {
		return err
	}
	*reply = *ip
	return nil
}

// V1ClearIPAllocations clears IP allocations from an IPAllocations object.
// If args.AllocationIDs is empty or nil, all allocations will be cleared.
func (s *IPService) V1ClearIPAllocations(ctx *context.Context, args *utils.ClearIPAllocationsArgs, reply *string) error {
	if missing := utils.MissingStructFields(args, []string{utils.ID}); len(missing) != 0 {
		return utils.NewErrMandatoryIeMissing(missing...)
	}

	tnt := args.Tenant
	if tnt == utils.EmptyString {
		tnt = s.cfg.GeneralCfg().DefaultTenant
	}

	lkID := guardian.Guardian.GuardIDs(utils.EmptyString,
		config.CgrConfig().GeneralCfg().LockingTimeout,
		utils.IPAllocationsLockKey(tnt, args.ID))
	defer guardian.Guardian.UnguardIDs(lkID)

	allocs, err := s.dm.GetIPAllocations(ctx, tnt, args.ID, true, true, utils.NonTransactional, nil)
	if err != nil {
		return err
	}
	if err := allocs.ClearAllocations(args.AllocationIDs); err != nil {
		return err
	}
	if err := s.storeIPAllocations(ctx, allocs); err != nil {
		return err
	}

	*reply = utils.OK
	return nil
}