import type { H3Event } from 'h3'
import {
  getSetting,
  setSetting,
  SETTINGS_ALLOWED_REFERER_HOSTS,
  SETTINGS_API_UPLOAD_TOKEN,
  SETTINGS_AUTO_DELETE_DAYS,
  SETTINGS_AUTO_DELETE_ENABLED_AT,
  SETTINGS_IMAGE_BASE_URL,
  SETTINGS_WEBP_QUALITY,
  isAllowRegistration
} from './db'

export function getRuntimeEnv(
  event: H3Event,
  envKey: string,
  configKey?: string
): string {
  try {
    const fromProcess = process.env[envKey]
    if (fromProcess) {
      return fromProcess
    }
  } catch {
    // process.env may be unavailable in some runtimes
  }

  if (configKey) {
    const config = useRuntimeConfig(event) as Record<string, unknown>
    const fromConfig = config[configKey]
    if (typeof fromConfig === 'string' && fromConfig.length > 0) {
      return fromConfig
    }
  }

  return ''
}

export function isAdminSecretConfigured(event: H3Event): boolean {
  return getAdminSecret(event).length > 0
}

export function getAdminSecret(event: H3Event): string {
  return getRuntimeEnv(event, 'ADMIN_SECRET', 'adminSecret')
    || getRuntimeEnv(event, 'NUXT_ADMIN_SECRET', 'adminSecret')
}

export type SettingSource = 'env' | 'db' | 'none'

export function normalizeImageBaseUrl(raw: string): string {
  return raw.trim().replace(/\/$/, '')
}

export function getImageBaseUrlFromEnv(event: H3Event): string {
  return normalizeImageBaseUrl(
    getRuntimeEnv(event, 'IMAGE_BASE_URL', 'imageBaseUrl')
  )
}

export function isImageBaseUrlEnvConfigured(event: H3Event): boolean {
  return getImageBaseUrlFromEnv(event).length > 0
}

export function getImageBaseUrlSource(event: H3Event): SettingSource {
  if (getSetting(SETTINGS_IMAGE_BASE_URL) !== null) return 'db'
  if (isImageBaseUrlEnvConfigured(event)) return 'env'
  return 'none'
}

export function getImageBaseUrlConfigured(event: H3Event): string {
  const dbRaw = getSetting(SETTINGS_IMAGE_BASE_URL)
  if (dbRaw !== null) return normalizeImageBaseUrl(dbRaw)
  return getImageBaseUrlFromEnv(event)
}

export function getImageBaseUrl(event: H3Event): string {
  const dbRaw = getSetting(SETTINGS_IMAGE_BASE_URL)
  if (dbRaw !== null) {
    const configured = normalizeImageBaseUrl(dbRaw)
    if (configured) return configured
  } else {
    const fromEnv = getImageBaseUrlFromEnv(event)
    if (fromEnv) return fromEnv
  }

  // 单域名部署：未配置时用当前请求的域名（支持反代转发头）
  const requestUrl = getRequestURL(event, {
    xForwardedHost: true,
    xForwardedProto: true
  })
  return requestUrl.origin
}

export function getApiUploadTokenFromEnv(event: H3Event): string {
  return (
    getRuntimeEnv(event, 'API_UPLOAD_TOKEN', 'apiUploadToken')
    || getRuntimeEnv(event, 'NUXT_API_UPLOAD_TOKEN', 'apiUploadToken')
  )
}

export function isApiUploadTokenEnvConfigured(event: H3Event): boolean {
  return getApiUploadTokenFromEnv(event).length > 0
}

export type ApiUploadTokenSource = SettingSource

export function getApiUploadTokenSource(event: H3Event): ApiUploadTokenSource {
  if (getApiUploadTokenFromEnv(event)) return 'env'
  if (getSetting(SETTINGS_API_UPLOAD_TOKEN)) return 'db'
  return 'none'
}

export function isApiUploadTokenConfigured(event: H3Event): boolean {
  return getApiUploadToken(event).length > 0
}

/** 优先级：环境变量 → SQLite settings → runtimeConfig */
export function getApiUploadToken(event: H3Event): string {
  const fromEnv = getApiUploadTokenFromEnv(event)
  if (fromEnv) return fromEnv

  const fromDb = getSetting(SETTINGS_API_UPLOAD_TOKEN)
  if (fromDb) return fromDb

  return ''
}

export const DEFAULT_WEBP_QUALITY = 80

export type WebpQualitySource = 'env' | 'db' | 'default'

export function parseWebpQuality(raw: string): number | null {
  const value = Number(raw)
  if (Number.isFinite(value) && value >= 1 && value <= 100) {
    return Math.round(value)
  }
  return null
}

export function getWebpQualityFromEnv(): string {
  try {
    return process.env.WEBP_QUALITY?.trim() ?? ''
  } catch {
    return ''
  }
}

export function isWebpQualityEnvConfigured(): boolean {
  return parseWebpQuality(getWebpQualityFromEnv()) !== null
}

export function getWebpQualitySource(): WebpQualitySource {
  if (getSetting(SETTINGS_WEBP_QUALITY) !== null) return 'db'
  if (isWebpQualityEnvConfigured()) return 'env'
  return 'default'
}

/** 优先级：SQLite settings → 环境变量 → 默认 80 */
export function getWebpQuality(_event?: H3Event): number {
  const dbRaw = getSetting(SETTINGS_WEBP_QUALITY)
  if (dbRaw !== null) {
    const fromDb = parseWebpQuality(dbRaw)
    if (fromDb !== null) return fromDb
  }

  const fromEnv = parseWebpQuality(getWebpQualityFromEnv())
  if (fromEnv !== null) return fromEnv

  return DEFAULT_WEBP_QUALITY
}

export function normalizeRefererHosts(raw: string): string {
  const seen = new Set<string>()
  const hosts: string[] = []
  for (const part of raw.split(',')) {
    const host = part.trim().toLowerCase()
    if (!host || seen.has(host)) continue
    seen.add(host)
    hosts.push(host)
  }
  return hosts.join(',')
}

export function getRefererHostsFromEnv(): string {
  try {
    return normalizeRefererHosts(process.env.ALLOWED_REFERER_HOSTS ?? '')
  } catch {
    return ''
  }
}

export function isRefererEnvConfigured(): boolean {
  return getRefererHostsFromEnv().length > 0
}

export function getRefererSource(): SettingSource {
  if (getSetting(SETTINGS_ALLOWED_REFERER_HOSTS) !== null) return 'db'
  if (isRefererEnvConfigured()) return 'env'
  return 'none'
}

/** 优先级：SQLite settings → 环境变量；均可不配置 */
export function getAllowedRefererHostsRaw(_event?: H3Event): string {
  const dbRaw = getSetting(SETTINGS_ALLOWED_REFERER_HOSTS)
  if (dbRaw !== null) return normalizeRefererHosts(dbRaw)
  return getRefererHostsFromEnv()
}

export function isRefererConfigured(event?: H3Event): boolean {
  return getAllowedRefererHostsRaw(event).length > 0
}

export const DEFAULT_AUTO_DELETE_DAYS = 0
export const MAX_AUTO_DELETE_DAYS = 3650

export type AutoDeleteDaysSource = 'env' | 'db' | 'default'

export function parseAutoDeleteDays(raw: string): number | null {
  const trimmed = raw.trim()
  if (!trimmed) return null

  const value = Number(trimmed)
  if (!Number.isFinite(value) || value < 0 || !Number.isInteger(value)) {
    return null
  }
  if (value > MAX_AUTO_DELETE_DAYS) {
    return null
  }
  return value
}

export function getAutoDeleteDaysFromEnv(): string {
  try {
    return process.env.AUTO_DELETE_DAYS?.trim() ?? ''
  } catch {
    return ''
  }
}

export function isAutoDeleteDaysEnvConfigured(): boolean {
  return parseAutoDeleteDays(getAutoDeleteDaysFromEnv()) !== null
}

export function getAutoDeleteDaysSource(): AutoDeleteDaysSource {
  if (getSetting(SETTINGS_AUTO_DELETE_DAYS) !== null) return 'db'
  if (isAutoDeleteDaysEnvConfigured()) return 'env'
  return 'default'
}

/** 优先级：SQLite settings → 环境变量 → 默认 0（关闭） */
export function getAutoDeleteDays(_event?: H3Event): number {
  const dbRaw = getSetting(SETTINGS_AUTO_DELETE_DAYS)
  if (dbRaw !== null) {
    const fromDb = parseAutoDeleteDays(dbRaw)
    if (fromDb !== null) return fromDb
  }

  const fromEnv = parseAutoDeleteDays(getAutoDeleteDaysFromEnv())
  if (fromEnv !== null) return fromEnv

  return DEFAULT_AUTO_DELETE_DAYS
}

export function getGlobalAutoDeleteEnabledAt(): string | null {
  const raw = getSetting(SETTINGS_AUTO_DELETE_ENABLED_AT)
  return raw?.trim() ? raw : null
}

export function getGlobalAutoDeletePolicy(): { days: number, enabledAt: string | null } {
  return {
    days: getAutoDeleteDays(),
    enabledAt: getGlobalAutoDeleteEnabledAt()
  }
}

export function setGlobalAutoDeletePolicy(days: number): void {
  const dbRaw = getSetting(SETTINGS_AUTO_DELETE_DAYS)
  const currentDays = dbRaw !== null ? (parseAutoDeleteDays(dbRaw) ?? 0) : 0
  const currentEnabledAt = getGlobalAutoDeleteEnabledAt()
  const now = new Date().toISOString()
  let enabledAt = currentEnabledAt

  if (days > 0 && currentDays === 0) {
    enabledAt = now
  } else if (days === 0) {
    enabledAt = null
  }

  setSetting(SETTINGS_AUTO_DELETE_DAYS, String(days))
  setSetting(SETTINGS_AUTO_DELETE_ENABLED_AT, enabledAt ?? '')
}

export function isValidRefererHost(host: string): boolean {
  return /^[a-z0-9]([a-z0-9-]*[a-z0-9])?(\.[a-z0-9]([a-z0-9-]*[a-z0-9])?)*$/i.test(host)
}

export function isValidImageBaseUrl(value: string): boolean {
  if (!value) return true
  try {
    const url = new URL(value)
    return url.protocol === 'http:' || url.protocol === 'https:'
  } catch {
    return false
  }
}

export function getSettingsPayload(event: H3Event) {
  const config = useRuntimeConfig(event)
  const webpQuality = getWebpQuality(event)
  const allowedRefererHosts = getAllowedRefererHostsRaw(event)
  const imageBaseUrl = getImageBaseUrl(event)
  const autoDeleteDays = getAutoDeleteDays(event)
  const appVersion = config.appVersion as string

  return {
    apiUploadToken: getApiUploadToken(event),
    tokenSource: getApiUploadTokenSource(event),
    envTokenOverride: isApiUploadTokenEnvConfigured(event),
    webpQuality,
    webpQualitySource: getWebpQualitySource(),
    allowedRefererHosts,
    refererSource: getRefererSource(),
    refererEnvFallback: getRefererHostsFromEnv(),
    imageBaseUrl,
    imageBaseUrlConfigured: getImageBaseUrlConfigured(event),
    imageBaseUrlSource: getImageBaseUrlSource(event),
    autoDeleteDays,
    autoDeleteDaysSource: getAutoDeleteDaysSource(),
    autoDeleteEnvFallback: parseAutoDeleteDays(getAutoDeleteDaysFromEnv()) ?? 0,
    allowRegistration: isAllowRegistration(),
    appVersion,
    env: {
      webpQuality,
      refererConfigured: allowedRefererHosts.length > 0,
      imageBaseUrl,
      appVersion
    }
  }
}