/** Base class for every error the chart-rule evaluator can throw. */
export class ChartRuleError extends Error {}

/**
 * A node whose `kind` is not in the vocabulary. The caller catches this and
 * shows the setting as "configured in code", read-only.
 */
export class UnknownNodeError extends ChartRuleError {
  constructor(public readonly kind?: string) {
    super(`Unknown chart-rule node: ${kind ?? '(missing kind)'}`);
    this.name = 'UnknownNodeError';
  }
}

/** A node evaluated to the wrong type of value (e.g. comparing non-numbers). */
export class RuleTypeError extends ChartRuleError {
  constructor(message: string) {
    super(message);
    this.name = 'RuleTypeError';
  }
}

/**
 * A structurally invalid node in a deserialized value: not an object, no string
 * `kind`, or a `literal` without a scalar `value`. Distinct from
 * `UnknownNodeError` (a well-formed node whose `kind` is simply not in the
 * vocabulary — the intentional escape hatch). Like the others it is a
 * `ChartRuleError`, so a caller reading an untrusted rule catches it instead of
 * a native `TypeError` (or, worse, an `undefined` slipping through silently).
 */
export class MalformedRuleError extends ChartRuleError {
  constructor(message: string) {
    super(message);
    this.name = 'MalformedRuleError';
  }
}

/** @deprecated v1 is non-recursive. Retained for source compatibility. */
export class RuleDepthError extends ChartRuleError {
  constructor(maxDepth: number) {
    super(`chart rule nested deeper than ${maxDepth} levels`);
    this.name = 'RuleDepthError';
  }
}