query

type Column struct {
	Name     string `json:"name"`
	Type     string `json:"type"`
	Nullable bool   `json:"nullable"`
	Comment  string `json:"comment,omitempty"`
}

type ExecutionContext struct {
	Tables      []TableInfo `json:"tables"`
	Connections []string    `json:"connections"`
}

type Executor interface {
	// Execute runs a query and returns results.
	Execute(ctx context.Context, sql string, limit int) (*QueryResult, error)

	// Describe returns information about a table.
	Describe(ctx context.Context, table TableIdentifier) (*TableSchema, error)
}

type NoopProvider struct{}

type Provider interface {
	// Name returns the provider name.
	Name() string

	// ResolveTable converts a URN to a query table identifier.
	ResolveTable(ctx context.Context, urn string) (*TableIdentifier, error)

	// GetTableAvailability checks if a table is queryable.
	GetTableAvailability(ctx context.Context, urn string) (*TableAvailability, error)

	// GetQueryExamples returns sample queries for a table.
	GetQueryExamples(ctx context.Context, urn string) ([]QueryExample, error)

	// GetExecutionContext returns context for querying multiple tables.
	GetExecutionContext(ctx context.Context, urns []string) (*ExecutionContext, error)

	// GetTableSchema returns the schema of a table.
	GetTableSchema(ctx context.Context, table TableIdentifier) (*TableSchema, error)

	// Close releases resources.
	Close() error
}

type QueryExample struct {
	Description string `json:"description"`
	SQL         string `json:"sql"`
}

type QueryResult struct {
	Columns []string        `json:"columns"`
	Rows    [][]interface{} `json:"rows"`
	Count   int             `json:"count"`
}

type TableAvailability struct {
	Available     bool   `json:"available"`
	QueryTable    string `json:"query_table,omitempty"`
	Connection    string `json:"connection,omitempty"`
	EstimatedRows *int64 `json:"estimated_rows,omitempty"`
	Error         string `json:"error,omitempty"`
}

type TableIdentifier struct {
	Catalog    string `json:"catalog,omitempty"`
	Schema     string `json:"schema"`
	Table      string `json:"table"`
	Connection string `json:"connection,omitempty"`
}

type TableInfo struct {
	URN           string `json:"urn"`
	QueryTable    string `json:"query_table"`
	Connection    string `json:"connection"`
	EstimatedRows *int64 `json:"estimated_rows,omitempty"`
}

type TableSchema struct {
	Columns    []Column `json:"columns"`
	PrimaryKey []string `json:"primary_key,omitempty"`
}