import type {
  ExportDeclaration,
  Identifier,
  SourceFile,
  VariableDeclaration,
} from "./ts7/ast-types.js";
import type { ModuleSourceCandidates } from "./module-source-candidates.js";
import type { CycleEarlyBinding } from "./program.js";

/** Early bindings computed for one module order of a program. */
export interface EarlyBindingsMemo {
  key: string;
  bindings: CycleEarlyBinding[];
}

/** Facts owned by one program snapshot. Strong collections are bounded by
 * the program lifecycle, so neither GC finalizers nor native weak handles
 * are needed, and newer snapshots cannot inherit stale package decisions. */
export class ProgramAnalysis {
  readonly createRequireReasons = new Map<VariableDeclaration, string | null>();
  readonly nodeEsmFiles = new Map<SourceFile, boolean>();
  readonly prunedNpmReexports = new Set<ExportDeclaration>();
  readonly moduleSourceCandidates = new Map<SourceFile, ModuleSourceCandidates>();
  /** The modules of every import cycle the exact initialization rule admitted. */
  readonly exactCycleMembers = new Set<SourceFile>();
  cycleEarlyBindings: EarlyBindingsMemo | null = null;
  moduleEarlyBindings: EarlyBindingsMemo | null = null;
  /** Top-level require declarations: the first reference to their bindings
   * that code running before the require can reach (requireEarlyReference). */
  readonly requireEarlyReferences = new Map<VariableDeclaration, Identifier | null>();
  /** Per file: the first top-level statement that can run user code. */
  readonly requireFirstRunnable = new Map<SourceFile, number>();

  clear(): void {
    this.createRequireReasons.clear();
    this.nodeEsmFiles.clear();
    this.prunedNpmReexports.clear();
    this.moduleSourceCandidates.clear();
    this.exactCycleMembers.clear();
    this.cycleEarlyBindings = null;
    this.moduleEarlyBindings = null;
    this.requireEarlyReferences.clear();
    this.requireFirstRunnable.clear();
  }
}