/**
 * Additional parameters passed to complex validation functions.
 */
export interface ValidatorFunctionParams {
    /** The entire original input data. */
    data: any,
}

/**
 * An interface representing the result of an attempted validation that failed.
 */
export interface ValidationErrorResult {
    /** Whether or not the validation succeeded. */
    valid: false

    /**
     * The human-readable error message(s) describing the issue.
     */
    message?: string | string[]

    /**
     * If true, validation of subsequent fields will stop.
     */
    stopValidation?: boolean
}

/**
 * An interface representing the result of an attempted validation that succeeded.
 */
export interface ValidationSuccessResult {
    /** Whether or not the validation succeeded. */
    valid: true

    /**
     * If the value was cast to a different type, or inferred, as a result of this validation,
     * provide it here. It will replace the input string as the value of the field in the form.
     */
    castValue?: any

    /**
     * If true, validation of subsequent fields will stop.
     */
    stopValidation?: boolean
}

/** All possible results of an attempted validation. */
export type ValidationResult = ValidationErrorResult | ValidationSuccessResult

/** A validator function that takes only the field key and the object value. */
export type SimpleValidatorFunction = (fieldName: string, inputValue: any) => ValidationResult | Promise<ValidationResult>

/** A validator function that takes the field key, the object value, and an object of contextual params. */
export type ComplexValidatorFunction = (fieldName: string, inputValue: any, params: ValidatorFunctionParams) => ValidationResult | Promise<ValidationResult>

/** Useful type alias for all allowed validator function signatures. */
export type ValidatorFunction = SimpleValidatorFunction | ComplexValidatorFunction

/**
 * A set of validation rules that are applied to input objects on validators.
 *
 * The keys of this object are deep-nested keys and can be used to validate
 * nested properties.
 *
 * For example, the key "user.links.*.url" refers to the "url" property of all
 * objects in the "links" array on the "user" object on:
 *
 * ```json
 * {
 *     "user": {
 *         "links": [
 *             {
 *                 "url": "..."
 *             },
 *             {
 *                 "url": "..."
 *             }
 *         ]
 *     }
 * }
 * ```
 */
export type ValidationRules = {[key: string]: ValidatorFunction | ValidatorFunction[]}

/** A type alias denoting that a particular type has been validated. */
export type Valid<T> = T