import type {ReducerFunction, ReducerPercentile} from "../reducer.js";
import type {Transformed} from "./basic.js";
import type {Map} from "./map.js";

/**
 * The built-in normalize basis implementations; one of:
 *
 * - *first* - the first value, as in an index chart
 * - *last* - the last value
 * - *min* - the minimum value
 * - *max* - the maximum value
 * - *mean* - the mean value (average)
 * - *median* - the median value
 * - *pXX* - the percentile value, where XX is a number in [00,99]
 * - *sum* - the sum of values
 * - *extent* - the minimum is mapped to zero, and the maximum to one
 * - *deviation* - subtract the mean, then divide by the standard deviation
 */
export type NormalizeBasisName =
  | "deviation"
  | "first"
  | "last"
  | "max"
  | "mean"
  | "median"
  | "min"
  | "sum"
  | "extent"
  | ReducerPercentile;

/**
 * A functional basis implementation: given an array of input channel *values*
 * for the current series, returns the corresponding basis number (divisor).
 */
export type NormalizeBasisFunction<T = any> = ReducerFunction<T, number>;

/**
 * How to normalize series values; one of:
 *
 * - a named basis method such as *first* or *median*
 * - a function that takes an array of series values and returns a basis number
 */
export type NormalizeBasis = NormalizeBasisName | NormalizeBasisFunction;

/** Options for the normalize transform. */
export interface NormalizeOptions {
  /** How to normalize series values; defaults to *first*. */
  basis?: NormalizeBasis;
}

/**
 * Groups data into series using the first channel of **z**, **fill**, or
 * **stroke** (if any), then derives new **x**, **x1**, and **x2** channels for
 * each corresponding input channel by normalizing to the given *basis*. For
 * example, if the series values are [*x₀*, *x₁*, *x₂*, …] and the *first* basis
 * is used, the derived series values would be [*x₀* / *x₀*, *x₁* / *x₀*, *x₂* /
 * *x₀*, …] as in an index chart.
 */
export function normalizeX<T>(options?: T & NormalizeOptions): Transformed<T>;
export function normalizeX<T>(basis?: NormalizeBasis, options?: T): Transformed<T>;

/**
 * Groups data into series using the first channel of **z**, **fill**, or
 * **stroke** (if any), then derives new **y**, **y1**, and **y2** channels for
 * each corresponding input channel by normalizing to the given *basis*. For
 * example, if the series values are [*y₀*, *y₁*, *y₂*, …] and the *first* basis
 * is used, the derived series values would be [*y₀* / *y₀*, *y₁* / *y₀*, *y₂* /
 * *y₀*, …] as in an index chart.
 */
export function normalizeY<T>(options?: T & NormalizeOptions): Transformed<T>;
export function normalizeY<T>(basis?: NormalizeBasis, options?: T): Transformed<T>;

/**
 * Given a normalize *basis*, returns a corresponding map implementation for use
 * with the map transform, allowing the normalization of arbitrary channels
 * instead of only **x** and **y**. For example, to normalize the **title**
 * channel:
 *
 * ```js
 * Plot.map({title: Plot.normalize("first")}, {x: "Date", title: "Close", stroke: "Symbol"})
 * ```
 */
export function normalize(basis: NormalizeBasis): Map;