engine

type ColumnDesc struct {
	Name       string `json:"name"`
	Type       string `json:"type"`
	Nullable   bool   `json:"nullable"`
	PrimaryKey bool   `json:"primary_key,omitempty"`
	// Default is the column default as the catalog spells it, nil when none.
	Default *string `json:"default,omitempty"`
}

type ColumnInfo struct {
	DB     string `json:"db"`
	Table  string `json:"table"`
	Column string `json:"column"`
	Type   string `json:"type"`
	// View is set for a column of a view (or a materialized view or a
	// foreign table): its base columns are unknown.
	View bool `json:"view,omitempty"`
}

type DialFunc func(ctx context.Context, network, addr string) (net.Conn, error)

type Engine interface {
	Connect(ctx context.Context, p config.Profile, secret []byte, dial DialFunc) (Session, error)
}

type Flavor string

type IndexDesc struct {
	Name    string   `json:"name"`
	Columns []string `json:"columns"`
	Unique  bool     `json:"unique,omitempty"`
	Primary bool     `json:"primary,omitempty"`
}

type Noticer interface {
	Notices() []string
}

type Plan struct {
	Root PlanNode `json:"root"`
	// Cost is the engine's total cost estimate for the statement, in its
	// own units (PostgreSQL Total Cost, MySQL query_cost, MariaDB cost), or
	// -1 when the engine gives none.
	Cost float64         `json:"cost"`
	Raw  json.RawMessage `json:"raw"`
}

type PlanNode struct {
	Table string `json:"table,omitempty"`
	// Access is one of the Access* constants for a table node, "" for a group.
	Access string `json:"access,omitempty"`
	// EstRows is the engine's estimate of rows examined per execution of the
	// node, or -1 when the engine has none.
	EstRows int64 `json:"est_rows"`
	// Sort and Temp report a sort or a temporary table. On a group they apply
	// to the output of the group's pipeline.
	Sort bool `json:"sort,omitempty"`
	Temp bool `json:"temp,omitempty"`
	// Correlated marks a subquery evaluated once per outer row.
	Correlated bool `json:"correlated,omitempty"`
	// NoJoinCond marks a table joined without a usable join condition, so
	// that every outer row reads all of it.
	NoJoinCond bool `json:"no_join_cond,omitempty"`
	// Recursive marks the group of a recursive CTE: how many times it
	// iterates is unknown to the planner, so its row estimate is a guess.
	Recursive bool `json:"recursive,omitempty"`
	// Detail is the engine's own label for the node, for display only.
	Detail   string     `json:"detail,omitempty"`
	Children []PlanNode `json:"children,omitempty"`
}

type Result struct {
	Columns []ResultColumn `json:"columns"`
	Rows    [][]any        `json:"rows"`
	// Truncated is set when the statement produced more than maxRows rows.
	Truncated bool `json:"truncated"`
	// Affected is the number of rows changed by a write-class statement.
	Affected int64 `json:"affected"`
	// CutCells lists the cells, as [row, column] indexes of Rows, whose
	// value was longer than MaxCellBytes and was cut while it was read.
	CutCells [][2]int `json:"cut_cells,omitempty"`
}

type ResultColumn struct {
	Label        string `json:"label"`
	OriginDB     string `json:"origin_db,omitempty"`
	OriginTable  string `json:"origin_table,omitempty"`
	OriginColumn string `json:"origin_column,omitempty"`
}

type Session interface {
	ServerVersion() string
	Flavor() Flavor
	// OriginColumns reports whether Run fills in result column origins.
	OriginColumns() bool
	// ExtraPrivileges lists the warnings about what the connection could do
	// beyond the profile tier.
	ExtraPrivileges(ctx context.Context, tier config.Tier) ([]string, error)
	Databases(ctx context.Context) ([]string, error)
	Tables(ctx context.Context, db string) ([]string, error)
	Describe(ctx context.Context, db, table string) (TableInfo, error)
	Columns(ctx context.Context, db string) ([]ColumnInfo, error)
	Explain(ctx context.Context, db, sql string) (Plan, error)
	// Run executes one classified statement. Write classes run in a
	// transaction and report Affected. Rows are capped at maxRows (no cap
	// when maxRows <= 0) and Truncated says whether more were available.
	Run(ctx context.Context, db string, st sqlclass.Statement, maxRows int) (Result, error)
	Ping(ctx context.Context) error
	Close() error
}

type TLSProber interface {
	ProbeTLS(ctx context.Context, p config.Profile) ([]*x509.Certificate, error)
}

type TableInfo struct {
	DB      string       `json:"db"`
	Table   string       `json:"table"`
	Columns []ColumnDesc `json:"columns"`
	Indexes []IndexDesc  `json:"indexes,omitempty"`
	// EstRows is the engine's row estimate, or -1 when it has none.
	EstRows int64 `json:"est_rows"`
}

type Transport struct {
	Mode, CA, Host string
	Plain          bool
	Tunneled       bool
}