package domain

import (
	"context"
	"time"

	"gorm.io/datatypes"
)

// ResourceFlowVersion represents versioned snapshots of resource flows for temporal tracking
// This enables MRV (Monitoring, Reporting, Verification) compliance and historical analysis
type ResourceFlowVersion struct {
	ID             string `gorm:"primaryKey;type:text"`
	ResourceFlowID string `gorm:"type:text;not null;index:idx_rfv_flow_version"`
	VersionNumber  int    `gorm:"type:integer;not null;index:idx_rfv_flow_version"`

	// Change tracking
	Changes      datatypes.JSON `gorm:"type:jsonb;not null"` // What changed (JSON diff)
	ChangedBy    string         `gorm:"type:text"`           // User ID who made the change
	ChangeReason string         `gorm:"type:text"`           // Why the change was made

	// Validity period
	ValidFrom time.Time  `gorm:"type:timestamp with time zone;not null;default:now()"`
	ValidTo   *time.Time `gorm:"type:timestamp with time zone"` // NULL means current version

	// Timestamps
	CreatedAt time.Time `gorm:"autoCreateTime;index"`

	// Associations
	ResourceFlow *ResourceFlow `gorm:"foreignKey:ResourceFlowID"`
}

// TableName specifies the table name for GORM
func (ResourceFlowVersion) TableName() string {
	return "resource_flow_versions"
}

type ResourceFlowVersionRepository interface {
	Create(ctx context.Context, version *ResourceFlowVersion) error
	GetByResourceFlowID(ctx context.Context, flowID string) ([]*ResourceFlowVersion, error)
	GetVersionAtTime(ctx context.Context, flowID string, timestamp time.Time) (*ResourceFlowVersion, error)
	GetCurrentVersion(ctx context.Context, flowID string) (*ResourceFlowVersion, error)
}