package iam

import (
	"fmt"

	"git.frostfs.info/TrueCloudLab/policy-engine/pkg/chain"
	"git.frostfs.info/TrueCloudLab/policy-engine/schema/s3"
)

var specialActionToS3OpMap = map[string][]string{
	specialS3ActionsListAllMyBuckets:                 {"s3:ListBuckets"},
	specialS3ActionsListBucket:                       {"s3:HeadBucket", "s3:GetBucketLocation", "s3:ListObjectsV1", "s3:ListObjectsV2"},
	specialS3ActionsListBucketVersions:               {"s3:ListBucketObjectVersions"},
	specialS3ActionsListBucketMultipartUploads:       {"s3:ListMultipartUploads"},
	specialS3ActionsGetBucketObjectLockConfiguration: {"s3:GetBucketObjectLockConfig"},
	specialS3ActionsGetEncryptionConfiguration:       {"s3:GetBucketEncryption"},
	specialS3ActionsGetLifecycleConfiguration:        {"s3:GetBucketLifecycle"},
	specialS3ActionsGetBucketACL:                     {"s3:GetBucketACL"},
	specialS3ActionsGetBucketCORS:                    {"s3:GetBucketCors"},
	specialS3ActionsPutBucketTagging:                 {"s3:PutBucketTagging", "s3:DeleteBucketTagging"},
	specialS3ActionsPutBucketObjectLockConfiguration: {"s3:PutBucketObjectLockConfig"},
	specialS3ActionsPutEncryptionConfiguration:       {"s3:PutBucketEncryption", "s3:DeleteBucketEncryption"},
	specialS3ActionsPutLifecycleConfiguration:        {"s3:PutBucketLifecycle", "s3:DeleteBucketLifecycle"},
	specialS3ActionsPutBucketACL:                     {"s3:PutBucketACL"},
	specialS3ActionsPutBucketCORS:                    {"s3:PutBucketCors", "s3:DeleteBucketCors"},
	specialS3ActionsDeleteBucketCORS:                 {"s3:DeleteBucketCors"},

	specialS3ActionsListMultipartUploadParts:   {"s3:ListParts"},
	specialS3ActionsGetObjectACL:               {"s3:GetObjectACL"},
	specialS3ActionsGetObject:                  {"s3:GetObject", "s3:HeadObject"},
	specialS3ActionsGetObjectVersion:           {"s3:GetObject", "s3:HeadObject"},
	specialS3ActionsGetObjectVersionACL:        {"s3:GetObjectACL"},
	specialS3ActionsGetObjectVersionAttributes: {"s3:GetObjectAttributes"},
	specialS3ActionsGetObjectVersionTagging:    {"s3:GetObjectTagging"},
	specialS3ActionsPutObjectACL:               {"s3:PutObjectACL"},
	specialS3ActionsPutObjectVersionACL:        {"s3:PutObjectACL"},
	specialS3ActionsPutObjectVersionTagging:    {"s3:PutObjectTagging"},
	specialS3ActionsPutObject: {
		"s3:PutObject", "s3:PostObject", "s3:CopyObject",
		"s3:UploadPart", "s3:UploadPartCopy", "s3:CreateMultipartUpload", "s3:CompleteMultipartUpload",
	},
	specialS3ActionsDeleteObjectVersionTagging: {"s3:DeleteObjectTagging"},
	specialS3ActionsDeleteObject:               {"s3:DeleteObject", "s3:DeleteMultipleObjects"},
	specialS3ActionsDeleteObjectVersion:        {"s3:DeleteObject", "s3:DeleteMultipleObjects"},
}

const (
	specialS3ActionsListAllMyBuckets                 = "s3:ListAllMyBuckets"
	specialS3ActionsListBucket                       = "s3:ListBucket"
	specialS3ActionsListBucketVersions               = "s3:ListBucketVersions"
	specialS3ActionsListBucketMultipartUploads       = "s3:ListBucketMultipartUploads"
	specialS3ActionsGetBucketObjectLockConfiguration = "s3:GetBucketObjectLockConfiguration"
	specialS3ActionsGetEncryptionConfiguration       = "s3:GetEncryptionConfiguration"
	specialS3ActionsGetLifecycleConfiguration        = "s3:GetLifecycleConfiguration"
	specialS3ActionsGetBucketACL                     = "s3:GetBucketAcl"
	specialS3ActionsGetBucketCORS                    = "s3:GetBucketCORS"
	specialS3ActionsPutBucketTagging                 = "s3:PutBucketTagging"
	specialS3ActionsPutBucketObjectLockConfiguration = "s3:PutBucketObjectLockConfiguration"
	specialS3ActionsPutEncryptionConfiguration       = "s3:PutEncryptionConfiguration"
	specialS3ActionsPutLifecycleConfiguration        = "s3:PutLifecycleConfiguration"
	specialS3ActionsPutBucketACL                     = "s3:PutBucketAcl"
	specialS3ActionsPutBucketCORS                    = "s3:PutBucketCORS"
	specialS3ActionsDeleteBucketCORS                 = "s3:DeleteBucketCORS"
	specialS3ActionsListMultipartUploadParts         = "s3:ListMultipartUploadParts"
	specialS3ActionsGetObjectACL                     = "s3:GetObjectAcl"
	specialS3ActionsGetObject                        = "s3:GetObject"
	specialS3ActionsGetObjectVersion                 = "s3:GetObjectVersion"
	specialS3ActionsGetObjectVersionACL              = "s3:GetObjectVersionAcl"
	specialS3ActionsGetObjectVersionAttributes       = "s3:GetObjectVersionAttributes"
	specialS3ActionsGetObjectVersionTagging          = "s3:GetObjectVersionTagging"
	specialS3ActionsPutObjectACL                     = "s3:PutObjectAcl"
	specialS3ActionsPutObjectVersionACL              = "s3:PutObjectVersionAcl"
	specialS3ActionsPutObjectVersionTagging          = "s3:PutObjectVersionTagging"
	specialS3ActionsPutObject                        = "s3:PutObject"
	specialS3ActionsDeleteObjectVersionTagging       = "s3:DeleteObjectVersionTagging"
	specialS3ActionsDeleteObject                     = "s3:DeleteObject"
	specialS3ActionsDeleteObjectVersion              = "s3:DeleteObjectVersion"
)

type S3Resolver interface {
	GetUserAddress(account, user string) (string, error)
}

func ConvertToS3Chain(p Policy, resolver S3Resolver) (*chain.Chain, error) {
	if err := p.Validate(ResourceBasedPolicyType); err != nil {
		return nil, err
	}

	var engineChain chain.Chain

	for _, statement := range p.Statement {
		status := formStatus(statement)

		actions, actionInverted := statement.action()
		s3Actions, err := formS3ActionNames(actions)
		if err != nil {
			return nil, err
		}
		ruleAction := chain.Actions{Inverted: actionInverted, Names: s3Actions}
		if len(ruleAction.Names) == 0 {
			continue
		}

		resources, resourceInverted := statement.resource()
		if err := validateS3ResourceNames(resources); err != nil {
			return nil, err
		}
		ruleResource := chain.Resources{Inverted: resourceInverted, Names: resources}

		groupedConditions, err := convertToS3ChainCondition(statement.Conditions, resolver)
		if err != nil {
			return nil, err
		}
		splitConditions := splitGroupedConditions(groupedConditions)

		principals, principalCondFn, err := getS3PrincipalsAndConditionFunc(statement, resolver)
		if err != nil {
			return nil, err
		}

		for _, principal := range principals {
			for _, conditions := range splitConditions {
				var principalCondition []chain.Condition
				if principal != Wildcard {
					principalCondition = []chain.Condition{principalCondFn(principal)}
				}

				r := chain.Rule{
					Status:    status,
					Actions:   ruleAction,
					Resources: ruleResource,
					Condition: append(principalCondition, conditions...),
				}
				engineChain.Rules = append(engineChain.Rules, r)
			}
		}
	}

	if len(engineChain.Rules) == 0 {
		return nil, ErrActionsNotApplicable
	}

	return &engineChain, nil
}

func getS3PrincipalsAndConditionFunc(statement Statement, resolver S3Resolver) ([]string, formPrincipalConditionFunc, error) {
	var principals []string
	var op chain.ConditionType
	statementPrincipal, inverted := statement.principal()
	if _, ok := statementPrincipal[Wildcard]; ok { // this can be true only if 'inverted' false
		principals = []string{Wildcard}
		op = chain.CondStringLike
	} else {
		for principalType, principal := range statementPrincipal {
			if principalType != AWSPrincipalType {
				return nil, nil, fmt.Errorf("unsupported principal type '%s'", principalType)
			}
			parsedPrincipal, err := formS3Principal(principal, resolver)
			if err != nil {
				return nil, nil, fmt.Errorf("parse principal: %w", err)
			}
			principals = append(principals, parsedPrincipal...)
		}

		op = chain.CondStringEquals
		if inverted {
			op = chain.CondStringNotEquals
		}
	}

	return principals, func(principal string) chain.Condition {
		return chain.Condition{
			Op:     op,
			Object: chain.ObjectRequest,
			Key:    s3.PropertyKeyOwner,
			Value:  principal,
		}
	}, nil
}

func convertToS3ChainCondition(c Conditions, resolver S3Resolver) ([]GroupedConditions, error) {
	return convertToChainConditions(c, func(gr GroupedConditions) (GroupedConditions, error) {
		for i := range gr.Conditions {
			if gr.Conditions[i].Key == condKeyAWSPrincipalARN {
				gr.Conditions[i].Key = s3.PropertyKeyOwner
				val, err := formPrincipalOwner(gr.Conditions[i].Value, resolver)
				if err != nil {
					return GroupedConditions{}, err
				}
				gr.Conditions[i].Value = val
			}
		}

		return gr, nil
	})
}

func formS3Principal(principal []string, resolver S3Resolver) ([]string, error) {
	res := make([]string, len(principal))

	var err error
	for i := range principal {
		if res[i], err = formPrincipalOwner(principal[i], resolver); err != nil {
			return nil, err
		}
	}

	return res, nil
}

func formPrincipalOwner(principal string, resolver S3Resolver) (string, error) {
	account, user, err := parsePrincipalAsIAMUser(principal)
	if err != nil {
		return "", err
	}

	address, err := resolver.GetUserAddress(account, user)
	if err != nil {
		return "", fmt.Errorf("get user address: %w", err)
	}

	return address, nil
}

func validateS3ResourceNames(names []string) error {
	for i := range names {
		if err := validateResource(names[i]); err != nil {
			return err
		}
	}

	return nil
}

func formS3ActionNames(names []string) ([]string, error) {
	res := make([]string, 0, len(names))

	for _, action := range names {
		if err := validateAction(action); err != nil {
			return nil, err
		}

		if action == Wildcard {
			return []string{Wildcard}, nil
		}

		if actions, ok := specialActionToS3OpMap[action]; ok {
			res = append(res, actions...)
		} else {
			res = append(res, action)
		}
	}

	return res, nil
}