"use client"

import { useEffect, useState } from "react"
import { useAuthStore } from "@/lib/api/auth-store"

function attachmentInlineUrl(attachmentId: string): string {
  const base = process.env.NEXT_PUBLIC_API_URL ?? "/api/v1"
  const normalizedBase = base.endsWith("/") ? base.slice(0, -1) : base
  return `${normalizedBase}/mail/attachments/${encodeURIComponent(attachmentId)}/inline`
}

function normalizeCidKey(raw: string): string {
  const trimmed = raw.trim()
  if (trimmed.toLowerCase().startsWith("cid:")) {
    return trimmed.slice(4).trim()
  }
  return trimmed
}

/** 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 accessToken = useAuthStore((s) => s.accessToken)
  const [urls, setUrls] = useState<Record<string, string>>({})

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

    let cancelled = false
    const objectUrls: string[] = []

    void (async () => {
      const next: Record<string, string> = {}
      for (const [contentId, attachmentId] of Object.entries(cidMap)) {
        if (!attachmentId) continue
        try {
          const res = await fetch(attachmentInlineUrl(attachmentId), {
            headers: { Authorization: `Bearer ${accessToken}` },
          })
          if (!res.ok) continue
          const blob = await res.blob()
          const blobUrl = URL.createObjectURL(blob)
          objectUrls.push(blobUrl)
          const key = normalizeCidKey(contentId)
          next[key] = blobUrl
          next[`cid:${key}`] = blobUrl
        } catch {
          // skip broken inline parts
        }
      }
      if (!cancelled) {
        setUrls(next)
      } else {
        for (const u of objectUrls) URL.revokeObjectURL(u)
      }
    })()

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

  return urls
}