/*
 * The MIT License (MIT)
 *
 * Copyright (c) 2015 - present Instructure, Inc.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

import type {
  ThemeOrOverride,
  Overrides,
  ComponentOverride
} from './EmotionTypes'
import type { ComponentTheme } from '@instructure/shared-types'
import { ThemeOverrideProp } from './withStyle'
import { ThemeOverrideValue } from './useStyle'

type ComponentName = keyof ComponentOverride | undefined

/**
 * ---
 * private: true
 * ---
 * This is a utility function which calculates the correct component theme
 * based on every possible override there is.

 * @param theme - Theme object
 * @param displayName - Name of the component
 * @param componentId - componentId of the component
 * @param themeOverride - The theme override object
 * @param componentTheme - The component's default theme
 * @returns The calculated theme override object
 */
const getComponentThemeOverride = (
  theme: ThemeOrOverride,
  displayName: string,
  componentId?: string,
  // ThemeOverrideProp is the old type, ThemeOverrideValue is the new one
  themeOverride?: ThemeOverrideProp['themeOverride'] | ThemeOverrideValue,
  componentTheme?: ComponentTheme
): Partial<ComponentTheme> => {
  const name = displayName as ComponentName
  const id = componentId as ComponentName

  const { componentOverrides } = theme as Overrides

  let overridesFromTheme: Partial<ComponentTheme> = {}
  let overrideFromComponent: Partial<ComponentTheme> = {}

  if (componentOverrides) {
    overridesFromTheme =
      (name && componentOverrides[name]) || (id && componentOverrides[id]) || {}
  }

  if (themeOverride) {
    if (typeof themeOverride === 'function') {
      overrideFromComponent = themeOverride(
        //TODO type properly when the old theme is gone
        componentTheme || ({} as any),
        // the `theme` technically could be a partial theme / override object too,
        // but we want to display all possible options
        theme as any
      )
    } else {
      overrideFromComponent = themeOverride
    }
  }

  return {
    ...overridesFromTheme,
    ...overrideFromComponent
  }
}

export default getComponentThemeOverride
export { getComponentThemeOverride }