import type { CookieOptions } from '#app'

export type ProjectDisplayMode = 'list' | 'grid' | 'gallery'
export type DarkColorTheme = 'dark' | 'oled' | 'retro'

export interface NumberFlag {
  min: number
  max: number
}

export type BooleanFlag = boolean

export type RadioFlag = ProjectDisplayMode | DarkColorTheme

export type FlagValue = BooleanFlag /* | NumberFlag | RadioFlag */

const validateValues = <K extends PropertyKey>(flags: Record<K, FlagValue>) => flags

export const DEFAULT_FEATURE_FLAGS = validateValues({
  // Developer flags
  developerMode: false,

  // In-development features, flags will be removed over time
  newProjectLinks: true,
  newProjectMembers: false,
  newProjectDetails: true,
  projectCompatibility: false,
  removeFeaturedVersions: false,

  // Alt layouts
  // searchSidebarRight: false,
  // projectSidebarRight: false,

  // Feature toggles
  // advancedRendering: true,
  // externalLinksNewTab: true,
  // notUsingBlockers: false,
  // hideModrinthAppPromos: false,
  // preferredDarkTheme: 'dark',
  // hideStagingBanner: false,

  // Project display modes
  // modSearchDisplayMode: 'list',
  // pluginSearchDisplayMode: 'list',
  // resourcePackSearchDisplayMode: 'gallery',
  // modpackSearchDisplayMode: 'list',
  // shaderSearchDisplayMode: 'gallery',
  // dataPackSearchDisplayMode: 'list',
  // userProjectDisplayMode: 'list',
  // collectionProjectDisplayMode: 'list',
} as const)

export type FeatureFlag = keyof typeof DEFAULT_FEATURE_FLAGS

export type AllFeatureFlags = {
  [key in FeatureFlag]: (typeof DEFAULT_FEATURE_FLAGS)[key]
}

export type PartialFeatureFlags = Partial<AllFeatureFlags>

const COOKIE_OPTIONS = {
  maxAge: 60 * 60 * 24 * 365 * 10,
  sameSite: 'lax',
  secure: true,
  httpOnly: false,
  path: '/',
} satisfies CookieOptions<PartialFeatureFlags>

export const useFeatureFlags = () =>
  useState<AllFeatureFlags>('featureFlags', () => {
    const config = useRuntimeConfig()

    const savedFlags = useCookie<PartialFeatureFlags>('featureFlags', COOKIE_OPTIONS)

    if (!savedFlags.value) {
      savedFlags.value = {}
    }

    const flags: AllFeatureFlags = JSON.parse(JSON.stringify(DEFAULT_FEATURE_FLAGS))

    const overrides = config.public.featureFlagOverrides as PartialFeatureFlags
    for (const key in overrides) {
      if (key in flags) {
        const flag = key as FeatureFlag
        const value = overrides[flag] as (typeof flags)[FeatureFlag]
        flags[flag] = value
      }
    }

    for (const key in savedFlags.value) {
      if (key in flags) {
        const flag = key as FeatureFlag
        const value = savedFlags.value[flag] as (typeof flags)[FeatureFlag]
        flags[flag] = value
      }
    }

    return flags
  })

export const saveFeatureFlags = () => {
  const flags = useFeatureFlags()
  const cookie = useCookie<PartialFeatureFlags>('featureFlags', COOKIE_OPTIONS)
  cookie.value = flags.value
}