import { API_BASE_URL } from "../config/constants"
import { authFetch } from "./client"

export type NotificationLevel = "info" | "success" | "warning" | "error"

export interface NotificationItem {
  id: string
  type: string
  title: string
  message: string
  level: NotificationLevel
  created_at: string
  is_seen: boolean
  delete_on_seen: boolean
  action_url?: string | null
  entity_type?: string | null
  entity_id?: string | null
  meta?: Record<string, unknown>
}

export interface NotificationsResponse {
  count: number
  unread_count: number
  notifications: NotificationItem[]
}

export interface NotificationStreamTokenResponse {
  token: string
  expires_in: number
}

export interface NotificationFilters {
  limit?: number
  offset?: number
  type?: string
}

const buildSearchParams = (filters: NotificationFilters = {}) => {
  const searchParams = new URLSearchParams()
  if (typeof filters.limit === "number") {
    searchParams.set("limit", String(filters.limit))
  }
  if (typeof filters.offset === "number") {
    searchParams.set("offset", String(filters.offset))
  }
  if (filters.type) {
    searchParams.set("type", filters.type)
  }
  const query = searchParams.toString()
  return query ? `?${query}` : ""
}

export const getNotifications = async (
  filters: NotificationFilters = {},
): Promise<NotificationsResponse> => {
  const response = await authFetch(`/api/notifications/list/${buildSearchParams(filters)}`)
  if (!response.ok) {
    throw new Error("Failed to load notifications")
  }
  return response.json()
}

export const markNotificationSeen = async (id: string) => {
  const response = await authFetch("/api/notifications/seen/", {
    method: "POST",
    body: JSON.stringify({ id }),
  })
  if (!response.ok) {
    throw new Error("Failed to mark notification as read")
  }
  return response.json()
}

export const deleteNotification = async (id: string) => {
  const response = await authFetch(`/api/notifications/${id}/`, {
    method: "DELETE",
  })
  if (!response.ok) {
    throw new Error("Failed to delete notification")
  }
  return response.json()
}

export const markAllNotificationsRead = async (type?: string) => {
  const response = await authFetch(`/api/notifications/seen/all/${buildSearchParams({ type })}`, {
    method: "POST",
    body: JSON.stringify(type ? { type } : {}),
  })
  if (!response.ok) {
    throw new Error("Failed to mark all notifications as read")
  }
  return response.json()
}

export const issueNotificationStreamToken = async (): Promise<NotificationStreamTokenResponse> => {
  const response = await authFetch("/api/notifications/stream-token/", {
    method: "POST",
  })
  if (!response.ok) {
    throw new Error("Failed to issue notification stream token")
  }
  return response.json()
}

export const buildNotificationStreamUrl = (token: string) => {
  const cleanBaseUrl = API_BASE_URL.replace(/\/+$/, "")
  return `${cleanBaseUrl}/api/notifications/stream/?token=${encodeURIComponent(token)}`
}

const REPORT_EXPORT_DOWNLOAD_PATTERN = /\/api\/reports\/exports\/[^/]+\/download\/?$/

const toApiEndpoint = (actionUrl: string) => {
  const cleanBaseUrl = API_BASE_URL.replace(/\/+$/, "")
  if (actionUrl.startsWith("http://") || actionUrl.startsWith("https://")) {
    if (!actionUrl.startsWith(cleanBaseUrl)) {
      return null
    }
    return actionUrl.slice(cleanBaseUrl.length) || "/"
  }
  return actionUrl.startsWith("/") ? actionUrl : `/${actionUrl}`
}

const getFilenameFromDisposition = (contentDisposition: string | null) => {
  if (!contentDisposition) return null

  const utfMatch = contentDisposition.match(/filename\*=UTF-8''([^;]+)/i)
  if (utfMatch?.[1]) {
    return decodeURIComponent(utfMatch[1])
  }

  const plainMatch = contentDisposition.match(/filename="?([^"]+)"?/i)
  return plainMatch?.[1] || null
}

export const isReportExportDownloadUrl = (actionUrl?: string | null) => {
  if (!actionUrl) return false
  const endpoint = toApiEndpoint(actionUrl)
  return !!endpoint && REPORT_EXPORT_DOWNLOAD_PATTERN.test(endpoint)
}

export const downloadNotificationFile = async (
  actionUrl: string,
  fallbackFilename?: string | null,
) => {
  const endpoint = toApiEndpoint(actionUrl)
  if (!endpoint) {
    throw new Error("Unsupported download url")
  }

  const response = await authFetch(endpoint, {
    method: "GET",
  })

  if (!response.ok) {
    throw new Error("Failed to download file")
  }

  const blob = await response.blob()
  const objectUrl = window.URL.createObjectURL(blob)
  const filename =
    getFilenameFromDisposition(response.headers.get("content-disposition")) ||
    fallbackFilename ||
    "download"

  const anchor = document.createElement("a")
  anchor.href = objectUrl
  anchor.download = filename
  document.body.appendChild(anchor)
  anchor.click()
  anchor.remove()
  window.URL.revokeObjectURL(objectUrl)
}