import type { DesiredState, ActualState, DdlOperation } from './types.js';
/**
 * Compares a desired schema state against the actual database state and
 * produces a sorted list of DDL operations needed to reconcile the two.
 */
export declare class DiffEngine {
    /** Compute the full set of DDL operations to bring `actual` in line with `desired`. */
    diff(desired: DesiredState, actual: ActualState): DdlOperation[];
    /** Build all operations needed to create a brand new table (table + indexes + foreign keys + check constraints). */
    private buildNewTableOperations;
    /** Generate the CREATE TABLE DDL for a table definition. */
    private buildCreateTableOp;
    /** Compare an existing table against its desired definition and produce update operations. */
    private diffTable;
    /** Detect added columns, type changes, and orphaned columns. */
    private diffColumns;
    /** Detect indexes that need to be created. */
    private diffIndexes;
    /** Detect foreign keys that need to be added. */
    private diffForeignKeys;
    /** Detect CHECK constraints that need to be added. */
    private diffCheckConstraints;
    /** Generate an ADD COLUMN operation. */
    private buildAddColumnOp;
    /** Generate an ALTER COLUMN TYPE operation. */
    private buildAlterColumnTypeOp;
    /** Generate a CREATE INDEX operation. */
    private buildCreateIndexOp;
    /** Generate an ADD FOREIGN KEY constraint operation. */
    private buildAddForeignKeyOp;
    /** Generate an ADD CHECK CONSTRAINT operation. */
    private buildAddCheckConstraintOp;
    /** Produce a warning operation for a table that exists in the DB but not in the schema. */
    private warnOrphanedTable;
    /** Produce a warning operation for a column that exists in the DB but not in the schema. */
    private warnOrphanedColumn;
    /** Convert a column definition to its SQL fragment (e.g. `"name" TEXT NOT NULL DEFAULT 'x'`). */
    private columnToSql;
    /** Check whether the column type has changed (case-insensitive comparison). */
    private hasColumnTypeChanged;
    /**
     * Sort operations so they execute in a safe dependency order:
     * 1. CREATE TABLE (tables must exist before columns/indexes reference them)
     * 2. ADD COLUMN
     * 3. ALTER COLUMN TYPE
     * 4. CREATE INDEX (columns must exist first)
     * 5. ADD FOREIGN KEY (referenced tables must exist first)
     * 6. ADD CHECK CONSTRAINT (columns must exist first)
     * 7. Destructive operations (always last, require explicit opt-in)
     */
    private sortByDependencyOrder;
}
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