package api

import (
	"crypto/sha256"
	"encoding/hex"
	"encoding/json"
)

// ProtectedSystemManifest describes a system that delegates authorization to
// flex-auth.
type ProtectedSystemManifest struct {
	ID             string             `json:"id"                         yaml:"id"`
	Name           string             `json:"name,omitempty"             yaml:"name,omitempty"`
	Description    string             `json:"description,omitempty"      yaml:"description,omitempty"`
	ResourceTypes  []ResourceType     `json:"resource_types,omitempty"   yaml:"resource_types,omitempty"`
	Actions        []ActionDefinition `json:"actions,omitempty"          yaml:"actions,omitempty"`
	CaringProfiles []string           `json:"caring_profiles,omitempty"  yaml:"caring_profiles,omitempty"`
	Metadata       map[string]any     `json:"metadata,omitempty"         yaml:"metadata,omitempty"`
}

// ResourceType describes a resource namespace entry owned by a protected system.
type ResourceType struct {
	Name        string         `json:"name"                   yaml:"name"`
	ParentTypes []string       `json:"parent_types,omitempty" yaml:"parent_types,omitempty"`
	ScopeLevel  ScopeLevel     `json:"scope_level,omitempty"  yaml:"scope_level,omitempty"`
	Planes      []Plane        `json:"planes,omitempty"       yaml:"planes,omitempty"`
	Metadata    map[string]any `json:"metadata,omitempty"     yaml:"metadata,omitempty"`
}

// ActionDefinition maps a protected-system action to CARING capabilities.
type ActionDefinition struct {
	Name          string         `json:"name"                     yaml:"name"`
	Capabilities  []Capability   `json:"capabilities,omitempty"   yaml:"capabilities,omitempty"`
	Planes        []Plane        `json:"planes,omitempty"         yaml:"planes,omitempty"`
	ExposureModes []ExposureMode `json:"exposure_modes,omitempty" yaml:"exposure_modes,omitempty"`
	Metadata      map[string]any `json:"metadata,omitempty"       yaml:"metadata,omitempty"`
}

// SubjectManifest declares subjects, groups, teams, and tenants for local
// registry loading.
type SubjectManifest struct {
	ID       string         `json:"id"                 yaml:"id"`
	Subjects []Subject      `json:"subjects,omitempty" yaml:"subjects,omitempty"`
	Groups   []Group        `json:"groups,omitempty"   yaml:"groups,omitempty"`
	Teams    []Team         `json:"teams,omitempty"    yaml:"teams,omitempty"`
	Tenants  []Tenant       `json:"tenants,omitempty"  yaml:"tenants,omitempty"`
	Metadata map[string]any `json:"metadata,omitempty" yaml:"metadata,omitempty"`
}

// Subject is a human, service, automation, agent, or other acting identity.
type Subject struct {
	ID                   string                   `json:"id"                              yaml:"id"`
	Type                 SubjectType              `json:"type"                            yaml:"type"`
	DisplayName          string                   `json:"display_name,omitempty"          yaml:"display_name,omitempty"`
	OrganizationRelation OrganizationRelation     `json:"organization_relation,omitempty" yaml:"organization_relation,omitempty"`
	Roles                []CanonicalRole          `json:"roles,omitempty"                 yaml:"roles,omitempty"`
	Groups               []string                 `json:"groups,omitempty"                yaml:"groups,omitempty"`
	Tenant               string                   `json:"tenant,omitempty"                yaml:"tenant,omitempty"`
	Claims               map[string]any           `json:"claims,omitempty"                yaml:"claims,omitempty"`
	CaringDescriptors    []CaringAccessDescriptor `json:"caring_descriptors,omitempty"    yaml:"caring_descriptors,omitempty"`
	Metadata             map[string]any           `json:"metadata,omitempty"              yaml:"metadata,omitempty"`
}

// Group is an assignment convenience, not a canonical role.
type Group struct {
	ID                string                   `json:"id"                             yaml:"id"`
	DisplayName       string                   `json:"display_name,omitempty"         yaml:"display_name,omitempty"`
	Members           []string                 `json:"members,omitempty"              yaml:"members,omitempty"`
	Tenant            string                   `json:"tenant,omitempty"               yaml:"tenant,omitempty"`
	CaringDescriptors []CaringAccessDescriptor `json:"caring_descriptors,omitempty"   yaml:"caring_descriptors,omitempty"`
	Metadata          map[string]any           `json:"metadata,omitempty"             yaml:"metadata,omitempty"`
}

// Team is a group-like ownership unit used by protected systems.
type Team struct {
	ID                string                   `json:"id"                             yaml:"id"`
	DisplayName       string                   `json:"display_name,omitempty"         yaml:"display_name,omitempty"`
	Members           []string                 `json:"members,omitempty"              yaml:"members,omitempty"`
	Tenant            string                   `json:"tenant,omitempty"               yaml:"tenant,omitempty"`
	CaringDescriptors []CaringAccessDescriptor `json:"caring_descriptors,omitempty"   yaml:"caring_descriptors,omitempty"`
	Metadata          map[string]any           `json:"metadata,omitempty"             yaml:"metadata,omitempty"`
}

// Tenant is a structural isolation boundary.
type Tenant struct {
	ID       string         `json:"id"                 yaml:"id"`
	Name     string         `json:"name,omitempty"     yaml:"name,omitempty"`
	Metadata map[string]any `json:"metadata,omitempty" yaml:"metadata,omitempty"`
}

// RelationshipFact records a relation between subjects, groups, teams, tenants,
// and resources.
type RelationshipFact struct {
	ID         string                  `json:"id"                   yaml:"id"`
	System     string                  `json:"system,omitempty"     yaml:"system,omitempty"`
	Subject    string                  `json:"subject"              yaml:"subject"`
	Relation   string                  `json:"relation"             yaml:"relation"`
	Object     string                  `json:"object"               yaml:"object"`
	Tenant     string                  `json:"tenant,omitempty"     yaml:"tenant,omitempty"`
	Conditions []Condition             `json:"conditions,omitempty" yaml:"conditions,omitempty"`
	Caring     *CaringAccessDescriptor `json:"caring,omitempty"     yaml:"caring,omitempty"`
	Provenance map[string]any          `json:"provenance,omitempty" yaml:"provenance,omitempty"`
	Metadata   map[string]any          `json:"metadata,omitempty"   yaml:"metadata,omitempty"`
}

// PolicyPackageMetadata is the frontmatter contract for Rego-in-Markdown
// policy packages.
type PolicyPackageMetadata struct {
	ID         string               `json:"id"                    yaml:"id"`
	Name       string               `json:"name,omitempty"        yaml:"name,omitempty"`
	Namespace  string               `json:"namespace,omitempty"   yaml:"namespace,omitempty"`
	Version    string               `json:"version"               yaml:"version"`
	Status     string               `json:"status,omitempty"      yaml:"status,omitempty"`
	Package    string               `json:"package"               yaml:"package"`
	Actions    []string             `json:"actions,omitempty"     yaml:"actions,omitempty"`
	Owner      string               `json:"owner,omitempty"       yaml:"owner,omitempty"`
	Fixtures   []string             `json:"fixtures,omitempty"    yaml:"fixtures,omitempty"`
	Caring     CaringPolicyMetadata `json:"caring"                yaml:"caring"`
	Activation map[string]any       `json:"activation,omitempty"  yaml:"activation,omitempty"`
	Metadata   map[string]any       `json:"metadata,omitempty"    yaml:"metadata,omitempty"`
}

// CaringPolicyMetadata declares the CARING envelope a policy governs.
type CaringPolicyMetadata struct {
	Profile               string                 `json:"profile"                            yaml:"profile"`
	Enforce               bool                   `json:"enforce,omitempty"                  yaml:"enforce,omitempty"`
	CanonicalRoles        []CanonicalRole        `json:"canonical_roles,omitempty"           yaml:"canonical_roles,omitempty"`
	OrganizationRelations []OrganizationRelation `json:"organization_relations,omitempty"    yaml:"organization_relations,omitempty"`
	Scopes                []CaringScope          `json:"scopes,omitempty"                    yaml:"scopes,omitempty"`
	Planes                []Plane                `json:"planes,omitempty"                    yaml:"planes,omitempty"`
	Capabilities          []Capability           `json:"capabilities,omitempty"              yaml:"capabilities,omitempty"`
	ExposureModes         []ExposureMode         `json:"exposure_modes,omitempty"            yaml:"exposure_modes,omitempty"`
	Conditions            []Condition            `json:"conditions,omitempty"                yaml:"conditions,omitempty"`
	Restrictions          []Restriction          `json:"restrictions,omitempty"              yaml:"restrictions,omitempty"`
	Metadata              map[string]any         `json:"metadata,omitempty"                  yaml:"metadata,omitempty"`
}

// PolicyFixture binds a check request to an expected decision.
type PolicyFixture struct {
	ID       string              `json:"id"                 yaml:"id"`
	Request  CheckRequest        `json:"request"            yaml:"request"`
	Expect   DecisionExpectation `json:"expect"             yaml:"expect"`
	Metadata map[string]any      `json:"metadata,omitempty" yaml:"metadata,omitempty"`
}

// DecisionExpectation is the compact fixture expectation for policy tests.
type DecisionExpectation struct {
	Effect              DecisionEffect             `json:"effect"                         yaml:"effect"`
	Reason              string                     `json:"reason,omitempty"               yaml:"reason,omitempty"`
	Obligations         []Obligation               `json:"obligations,omitempty"          yaml:"obligations,omitempty"`
	ConformanceFindings []CaringConformanceFinding `json:"conformance_findings,omitempty" yaml:"conformance_findings,omitempty"`
}

// CheckRequest is the stable protected-system-facing decision request.
type CheckRequest struct {
	ID            string                  `json:"id,omitempty"             yaml:"id,omitempty"`
	Tenant        string                  `json:"tenant,omitempty"         yaml:"tenant,omitempty"`
	Subject       SubjectRef              `json:"subject"                  yaml:"subject"`
	Action        string                  `json:"action"                   yaml:"action"`
	Resource      ResourceRef             `json:"resource"                 yaml:"resource"`
	Context       map[string]any          `json:"context,omitempty"        yaml:"context,omitempty"`
	CaringContext *CaringAccessDescriptor `json:"caring_context,omitempty" yaml:"caring_context,omitempty"`
	PolicyVersion string                  `json:"policy_version,omitempty" yaml:"policy_version,omitempty"`
}

// BatchCheckRequest evaluates one subject/action against multiple resources.
type BatchCheckRequest struct {
	ID            string         `json:"id,omitempty"             yaml:"id,omitempty"`
	Tenant        string         `json:"tenant,omitempty"         yaml:"tenant,omitempty"`
	Subject       SubjectRef     `json:"subject"                  yaml:"subject"`
	Action        string         `json:"action"                   yaml:"action"`
	Resources     []ResourceRef  `json:"resources"                yaml:"resources"`
	Context       map[string]any `json:"context,omitempty"        yaml:"context,omitempty"`
	PolicyVersion string         `json:"policy_version,omitempty" yaml:"policy_version,omitempty"`
}

// SubjectRef is a normalized subject reference in request and decision shapes.
type SubjectRef struct {
	ID         string         `json:"id"                   yaml:"id"`
	Type       SubjectType    `json:"type,omitempty"       yaml:"type,omitempty"`
	Tenant     string         `json:"tenant,omitempty"     yaml:"tenant,omitempty"`
	Attributes map[string]any `json:"attributes,omitempty" yaml:"attributes,omitempty"`
}

// ResourceRef is a normalized resource reference in request and decision shapes.
type ResourceRef struct {
	ID         string         `json:"id"                   yaml:"id"`
	Type       string         `json:"type,omitempty"       yaml:"type,omitempty"`
	System     string         `json:"system,omitempty"     yaml:"system,omitempty"`
	Tenant     string         `json:"tenant,omitempty"     yaml:"tenant,omitempty"`
	Attributes map[string]any `json:"attributes,omitempty" yaml:"attributes,omitempty"`
}

// DecisionEffect is the stable decision outcome vocabulary.
type DecisionEffect string

const (
	DecisionEffectAllow         DecisionEffect = "allow"
	DecisionEffectDeny          DecisionEffect = "deny"
	DecisionEffectRedact        DecisionEffect = "redact"
	DecisionEffectAuditOnly     DecisionEffect = "audit_only"
	DecisionEffectNotApplicable DecisionEffect = "not_applicable"
)

// DecisionEnvelope is the stable response produced by standalone and delegated
// evaluators.
type DecisionEnvelope struct {
	ID                   string                  `json:"id"                              yaml:"id"`
	RequestID            string                  `json:"request_id,omitempty"            yaml:"request_id,omitempty"`
	Effect               DecisionEffect          `json:"effect"                          yaml:"effect"`
	Reason               string                  `json:"reason,omitempty"                yaml:"reason,omitempty"`
	MatchedPolicyVersion string                  `json:"matched_policy_version,omitempty" yaml:"matched_policy_version,omitempty"`
	MatchedRule          string                  `json:"matched_rule,omitempty"          yaml:"matched_rule,omitempty"`
	Resource             ResourceRef             `json:"resource"                        yaml:"resource"`
	Subject              SubjectRef              `json:"subject"                         yaml:"subject"`
	Binding              *DecisionBinding        `json:"binding,omitempty"               yaml:"binding,omitempty"`
	Obligations          []Obligation            `json:"obligations,omitempty"           yaml:"obligations,omitempty"`
	Diagnostics          map[string]any          `json:"diagnostics,omitempty"           yaml:"diagnostics,omitempty"`
	Provenance           DecisionProvenance      `json:"provenance"                      yaml:"provenance"`
	Caring               *CaringDecisionMetadata `json:"caring,omitempty"                yaml:"caring,omitempty"`
}

// DecisionBinding is the exact normalized authorization request evaluated by
// a decision. It lets a consumer verify structured action, target, actor, and
// context fields without parsing reason or diagnostic prose.
type DecisionBinding struct {
	Tenant        string         `json:"tenant,omitempty"         yaml:"tenant,omitempty"`
	Subject       SubjectRef     `json:"subject"                  yaml:"subject"`
	Action        string         `json:"action"                   yaml:"action"`
	Resource      ResourceRef    `json:"resource"                 yaml:"resource"`
	Context       map[string]any `json:"context,omitempty"        yaml:"context,omitempty"`
	RequestDigest string         `json:"request_digest"           yaml:"request_digest"`
}

// NewDecisionBinding returns a stable structured binding for the exact request
// an evaluator consumed.
func NewDecisionBinding(request CheckRequest) *DecisionBinding {
	data, _ := json.Marshal(request)
	sum := sha256.Sum256(data)
	contextCopy := make(map[string]any, len(request.Context))
	for key, value := range request.Context {
		contextCopy[key] = value
	}
	return &DecisionBinding{
		Tenant:        request.Tenant,
		Subject:       request.Subject,
		Action:        request.Action,
		Resource:      request.Resource,
		Context:       contextCopy,
		RequestDigest: "sha256:" + hex.EncodeToString(sum[:]),
	}
}

// ActionAuthorizationStatus is the lifecycle state of a durable authorization.
type ActionAuthorizationStatus string

const (
	ActionAuthorizationPending    ActionAuthorizationStatus = "pending"
	ActionAuthorizationApproved   ActionAuthorizationStatus = "approved"
	ActionAuthorizationDenied     ActionAuthorizationStatus = "denied"
	ActionAuthorizationSuperseded ActionAuthorizationStatus = "superseded"
	ActionAuthorizationExpired    ActionAuthorizationStatus = "expired"
	ActionAuthorizationRevoked    ActionAuthorizationStatus = "revoked"
)

// ActionAuthorization joins a durable approval lifecycle to one exact
// flex-auth request and decision. Storage and approval collection remain the
// responsibility of the organizational decision authority.
type ActionAuthorization struct {
	SchemaVersion string                       `json:"schema_version"          yaml:"schema_version"`
	ID            string                       `json:"id"                      yaml:"id"`
	Status        ActionAuthorizationStatus    `json:"status"                  yaml:"status"`
	SupersededBy  string                       `json:"superseded_by,omitempty" yaml:"superseded_by,omitempty"`
	Request       CheckRequest                 `json:"request"                 yaml:"request"`
	Validity      ActionAuthorizationValidity  `json:"validity"                yaml:"validity"`
	Approvals     ActionAuthorizationApprovals `json:"approvals"               yaml:"approvals"`
	Decision      DecisionEnvelope             `json:"decision"                yaml:"decision"`
	Provenance    map[string]any               `json:"provenance,omitempty"    yaml:"provenance,omitempty"`
}

// ActionAuthorizationValidity bounds execution of an approved action.
type ActionAuthorizationValidity struct {
	NotBefore string `json:"not_before,omitempty" yaml:"not_before,omitempty"`
	ExpiresAt string `json:"expires_at"            yaml:"expires_at"`
}

// ActionAuthorizationApprovals declares the approval threshold and evidence.
type ActionAuthorizationApprovals struct {
	RequiredCount int                                `json:"required_count" yaml:"required_count"`
	Entries       []ActionAuthorizationApprovalEntry `json:"entries"        yaml:"entries"`
}

// ActionAuthorizationApprovalEntry is one authenticated approver's evidence.
type ActionAuthorizationApprovalEntry struct {
	SubjectID   string `json:"subject_id"             yaml:"subject_id"`
	ApprovedAt  string `json:"approved_at"            yaml:"approved_at"`
	Assurance   string `json:"assurance,omitempty"    yaml:"assurance,omitempty"`
	EvidenceRef string `json:"evidence_ref,omitempty" yaml:"evidence_ref,omitempty"`
}

// Obligation describes a follow-up behavior required by a decision.
type Obligation struct {
	Type       string         `json:"type"                 yaml:"type"`
	Parameters map[string]any `json:"parameters,omitempty" yaml:"parameters,omitempty"`
}

// DecisionProvenance captures evaluator and policy provenance.
type DecisionProvenance struct {
	Evaluator     string `json:"evaluator"                  yaml:"evaluator"`
	Mode          string `json:"mode"                       yaml:"mode"`
	PolicyPackage string `json:"policy_package,omitempty"   yaml:"policy_package,omitempty"`
	PolicyVersion string `json:"policy_version,omitempty"   yaml:"policy_version,omitempty"`
	DirectoryETag string `json:"directory_etag,omitempty"   yaml:"directory_etag,omitempty"`
	DecisionTime  string `json:"decision_time,omitempty"    yaml:"decision_time,omitempty"`
}

// CaringDecisionMetadata carries CARING descriptor and conformance details in
// a decision envelope.
type CaringDecisionMetadata struct {
	Profile               string                     `json:"profile"                          yaml:"profile"`
	Descriptor            *CaringAccessDescriptor    `json:"descriptor,omitempty"              yaml:"descriptor,omitempty"`
	RestrictionsEvaluated []Restriction              `json:"restrictions_evaluated,omitempty"  yaml:"restrictions_evaluated,omitempty"`
	ExposureModes         []ExposureMode             `json:"exposure_modes,omitempty"          yaml:"exposure_modes,omitempty"`
	DerivedCapabilities   []CaringDerivedCapability  `json:"derived_capabilities,omitempty"    yaml:"derived_capabilities,omitempty"`
	ConformanceFindings   []CaringConformanceFinding `json:"conformance_findings,omitempty"    yaml:"conformance_findings,omitempty"`
	ExposureEvent         *CaringExposureEvent       `json:"exposure_event,omitempty"          yaml:"exposure_event,omitempty"`
}

// AuditEvent is the local log shape for decisions and exposure events.
type AuditEvent struct {
	ID            string               `json:"id"                       yaml:"id"`
	Type          string               `json:"type"                     yaml:"type"`
	DecisionID    string               `json:"decision_id,omitempty"     yaml:"decision_id,omitempty"`
	Subject       SubjectRef           `json:"subject"                  yaml:"subject"`
	Resource      ResourceRef          `json:"resource,omitempty"        yaml:"resource,omitempty"`
	Action        string               `json:"action,omitempty"          yaml:"action,omitempty"`
	Effect        DecisionEffect       `json:"effect,omitempty"          yaml:"effect,omitempty"`
	Timestamp     string               `json:"timestamp,omitempty"       yaml:"timestamp,omitempty"`
	ExposureEvent *CaringExposureEvent `json:"exposure_event,omitempty"  yaml:"exposure_event,omitempty"`
	Metadata      map[string]any       `json:"metadata,omitempty"        yaml:"metadata,omitempty"`
}