/**
 * Pure, React-Native-agnostic resolution helpers for the Expo Text Input element
 * (NAM-1148). Kept free of any `react-native` import so they can be unit-tested
 * under the package's `node` jest environment (see
 * tests/components/elements/textInputStyle.test.ts).
 *
 * These mirror the Web sibling (sdk/web/src/components/elements/TextInput.ts) and
 * the Apple (NAM-1142) / Android (NAM-1143) native ports: a 4-state style
 * precedence (error > focused > filled > empty) and larger `television` defaults
 * applied only where the payload omits a value. Values are returned raw (colors as
 * payload strings, sizes as numbers); the component applies `parseColor`/`parseSize`.
 */

import type { TTextInputComponent, TTextInputType, FormFieldValidator } from '@namiml/sdk-core';

/**
 * TV defaults applied when the form factor is `television` and the payload omits
 * the value. Mirrors the Web `TV_DEFAULTS` and the native ports.
 */
export const TV_DEFAULTS = {
  borderWidth: 2,
  borderRadius: 6,
  width: 500,
  fontSize: 20,
  spacing: 16,
  innerPadding: 16,
};

export interface ResolvedInputVisual {
  borderColor: string;
  borderWidth: number;
  borderRadius: number;
  fillColor: string;
  fontColor?: string;
  fontSize?: number | string;
  padding: { top: number; right: number; bottom: number; left: number };
}

interface StateFlags {
  focused: boolean;
  hasError: boolean;
  isTelevision: boolean;
}

/** `null`/`undefined` numeric prop → TV fallback (or 0); otherwise `Number(value)`. */
function resolveBorderWidth(base: number | string | undefined, isTelevision: boolean): number {
  if (base == null) return isTelevision ? TV_DEFAULTS.borderWidth : 0;
  return Number(base);
}

/** Map the wire `type` to the validator's `TTextInputType` (email → email, else name). */
export function validatorType(component: Pick<TTextInputComponent, 'type'>): TTextInputType {
  return component.type === 'email' ? 'email' : 'name';
}

/** Build the field's validator from the (misspelled) `reqed` flag + author message. */
export function resolveValidator(component: TTextInputComponent): FormFieldValidator {
  return {
    type: validatorType(component),
    required: component.reqed === true,
    message: component.validationMessage,
  };
}

/**
 * The label to render, or `undefined` when there is no label. Appends ` *` when the
 * field is required, matching the Web renderer.
 */
export function resolveLabelText(component: TTextInputComponent): string | undefined {
  if (component.labelPosition === 'none') return undefined;
  if (!component.labelText) return undefined;
  return component.reqed === true ? `${component.labelText} *` : component.labelText;
}

/**
 * Resolve the input's visual properties under the 4-state precedence
 * error > focused > filled > empty. Filled and empty share the resting style; the
 * distinction is preserved for parity with the native ports.
 */
export function resolveInputVisual(
  component: TTextInputComponent,
  { focused, hasError, isTelevision }: StateFlags,
): ResolvedInputVisual {
  let borderColor = component.borderColor || 'transparent';
  let borderWidth = resolveBorderWidth(component.borderWidth, isTelevision);
  let borderRadius = Number(component.borderRadius ?? (isTelevision ? TV_DEFAULTS.borderRadius : 0));
  let fillColor = component.fillColor || 'transparent';

  if (focused) {
    borderColor = component.focusedBorderColor || borderColor;
    borderWidth = resolveBorderWidth(component.focusedBorderWidth ?? component.borderWidth, isTelevision);
    borderRadius = Number(component.focusedBorderRadius ?? component.borderRadius ?? borderRadius);
    fillColor = component.focusedFillColor || fillColor;
  }

  if (hasError) {
    borderColor = component.errorBorderColor || borderColor;
    borderWidth = resolveBorderWidth(component.errorBorderWidth ?? component.borderWidth, isTelevision);
    borderRadius = Number(component.errorBorderRadius ?? component.borderRadius ?? borderRadius);
  }

  const fontSize = component.fontSize ?? (isTelevision ? TV_DEFAULTS.fontSize : undefined);
  const fallbackPad = isTelevision ? TV_DEFAULTS.innerPadding : 0;

  return {
    borderColor,
    borderWidth,
    borderRadius,
    fillColor,
    fontColor: component.fontColor,
    fontSize,
    padding: {
      top: Number(component.innerTopPadding ?? fallbackPad),
      right: Number(component.innerRightPadding ?? fallbackPad),
      bottom: Number(component.innerBottomPadding ?? fallbackPad),
      left: Number(component.innerLeftPadding ?? fallbackPad),
    },
  };
}

/** Spacing between label / input / error, in points. TV gets a default gap. */
export function resolveSpacing(component: TTextInputComponent, isTelevision: boolean): number {
  const { spacing } = component;
  if (spacing == null) return isTelevision ? TV_DEFAULTS.spacing : 0;
  return Number(spacing);
}

/**
 * Whether this field should claim autofocus on mount (NAM-1529), mirroring the
 * button `focused` precedent (`NamiButton.tsx`): the payload's `focused` flag
 * only applies while the surrounding focus scope (`useFocusEnabled`) allows it,
 * so an off-screen/inactive step never steals focus. The mobile-vs-TV split
 * (keyboard raise vs. d-pad-only) lives in `useTVPreferredFocus`
 * (utils/tvFocus.ts) — this only decides whether autofocus applies at all.
 */
export function resolveAutoFocus(
  component: Pick<TTextInputComponent, 'focused'>,
  focusEnabled: boolean,
): boolean {
  return focusEnabled && Boolean(component.focused);
}