"use client"

import { useEffect, useState } from "react"
import { apiClient } from "@/lib/api/client"
import { registerCidUrlAliases } from "@/lib/mail-cid"

/** Fetches inline attachment blobs and exposes blob: URLs keyed by cid (with or without cid: prefix). */
export function useInlineCidUrls(cidMap: Record<string, string> | undefined) {
  const [urls, setUrls] = useState<Record<string, string>>({})

  useEffect(() => {
    if (!cidMap || Object.keys(cidMap).length === 0) {
      setUrls({})
      return
    }

    let cancelled = false
    const objectUrls: string[] = []
    void (async () => {
      const next: Record<string, string> = {}
      const blobByAttachmentId = new Map<string, string>()

      for (const [contentId, attachmentId] of Object.entries(cidMap)) {
        if (!attachmentId) continue
        let blobUrl = blobByAttachmentId.get(attachmentId)
        if (!blobUrl) {
          try {
            const blob = await apiClient.getBlob(
              `/mail/attachments/${encodeURIComponent(attachmentId)}/inline`
            )
            blobUrl = URL.createObjectURL(blob)
            blobByAttachmentId.set(attachmentId, blobUrl)
            objectUrls.push(blobUrl)
          } catch {
            continue
          }
        }
        registerCidUrlAliases(next, contentId, blobUrl)
      }
      if (!cancelled) {
        setUrls(next)
      } else {
        for (const u of objectUrls) URL.revokeObjectURL(u)
      }
    })()

    return () => {
      cancelled = true
      for (const u of objectUrls) URL.revokeObjectURL(u)
    }
  }, [cidMap])

  return urls
}