import { NextRequest, NextResponse } from "next/server"
import { writeFile } from "fs/promises"
import { join } from "path"
import { v4 as uuidv4 } from "uuid"
import path from "path"
import { revalidateTag } from "next/cache" // ✅ 추가

import db from "@/db/db"
import {
  documents,
  issueStages,
  revisions,
  documentAttachments,
} from "@/db/schema/vendorDocu"
import { and, eq } from "drizzle-orm"

/* ① change log 유틸 */
import {
  logRevisionChange,
  logAttachmentChange,
} from "@/lib/vendor-document-list/sync-service"

export async function POST(request: NextRequest) {
  try {
    const formData = await request.formData()

    /* ------- 파라미터 파싱 ------- */
    const stage            = formData.get("stage")        as string | null
    const revision         = formData.get("revision")     as string | null
    const docId            = Number(formData.get("documentId"))
    const uploaderName     = formData.get("uploaderName") as string | null
    const usage          = formData.get("usage")      as string | null
    const usageType          = formData.get("usageType")      as string | null
    const comment          = formData.get("comment")      as string | null
    const mode             = (formData.get("mode") || "new") as string // 'new'|'append'
    const targetSystem     = (formData.get("targetSystem") as string | null) ?? "DOLCE"
    const attachmentFiles  = formData.getAll("attachments") as File[]

    /* ------- 검증 ------- */
    if (!docId || Number.isNaN(docId))
      return NextResponse.json({ error: "Invalid documentId" }, { status: 400 })
    if (!stage || !revision)
      return NextResponse.json({ error: "Missing stage or revision" }, { status: 400 })
    if (!attachmentFiles.length)
      return NextResponse.json({ error: "No files provided" }, { status: 400 })

    const MAX = 3 * 1024 * 1024 * 1024 // 3 GB
    for (const f of attachmentFiles)
      if (f.size > MAX)
        return NextResponse.json(
          { error: `${f.name} > 3 GB` },
          { status: 400 }
        )

    /* ------- 계약 ID 확보 ------- */
    const [{ contractId }] = await db
      .select({ contractId: documents.contractId })
      .from(documents)
      .where(eq(documents.id, docId))
      .limit(1)

    /* ------- 트랜잭션 ------- */
    const result = await db.transaction(async (tx) => {
      /* 1) Stage */
      let issueStageId: number
      const [stageRow] = await tx
        .select({ id: issueStages.id })
        .from(issueStages)
        .where(and(
          eq(issueStages.stageName, stage),
          eq(issueStages.documentId, docId)
        ))
        .limit(1)

      if (!stageRow) {
        const [s] = await tx.insert(issueStages)
          .values({ documentId: docId, stageName: stage, updatedAt: new Date() })
          .returning({ id: issueStages.id })
        issueStageId = s.id
      } else issueStageId = stageRow.id

      /* 2) Revision */
      const today = new Date().toISOString().slice(0, 10)
      let revisionId: number
      const [revRow] = await tx
        .select()
        .from(revisions)
        .where(and(
          eq(revisions.issueStageId, issueStageId),
          eq(revisions.revision, revision)
        ))
        .limit(1)

      if (!revRow || mode === "new") {
        /* --- CREATE --- */
        const [newRev] = await tx.insert(revisions)
          .values({
            issueStageId,
            revision,
            uploaderType: "vendor",
            uploaderName: uploaderName ?? undefined,
            revisionStatus: "UPLOADED",
            uploadedAt: today,
            comment: comment ?? undefined,
            updatedAt: new Date(),
          })
          .returning()
        revisionId = newRev.id

        // change_logs: CREATE
        await logRevisionChange(
          contractId,
          revisionId,
          "CREATE",
          newRev,
          undefined,
          undefined,
          uploaderName ?? undefined,
          [targetSystem]
        )
      } else {
        /* --- UPDATE --- */
        await tx.update(revisions)
          .set({
            uploaderName: uploaderName ?? revRow.uploaderName,
            comment: comment ?? revRow.comment,
            updatedAt: new Date(),
          })
          .where(eq(revisions.id, revRow.id))

        const [updated] = await tx
          .select()
          .from(revisions)
          .where(eq(revisions.id, revRow.id))

        revisionId = revRow.id

        await logRevisionChange(
          contractId,
          revisionId,
          "UPDATE",
          updated,
          revRow,
          undefined,
          uploaderName ?? undefined,
          [targetSystem]
        )
      }

      /* 3) Attachments */
      const uploadedFiles: any[] = []
      const baseDir = join(process.cwd(), "public", "documents")

      for (const file of attachmentFiles) {
        const ext   = path.extname(file.name)
        const fname = uuidv4() + ext
        const dest  = join(baseDir, fname)

        await writeFile(dest, Buffer.from(await file.arrayBuffer()))

        const [att] = await tx.insert(documentAttachments)
          .values({
            revisionId,
            fileName: file.name,
            filePath: "/documents/" + fname,
            fileSize: file.size,
            fileType: ext.slice(1).toLowerCase() || undefined,
            updatedAt: new Date(),
          })
          .returning()

        uploadedFiles.push({
          id: att.id,
          fileName: file.name,
          fileSize: file.size,
          filePath: att.filePath,
        })

        // change_logs: attachment CREATE
        await logAttachmentChange(
          contractId,
          att.id,
          "CREATE",
          att,
          undefined,
          undefined,
          uploaderName ?? undefined,
          [targetSystem]
        )
      }

      /* 4) documents.updatedAt */
      await tx.update(documents)
        .set({ updatedAt: new Date() })
        .where(eq(documents.id, docId))

      return { revisionId, stage, revision, uploadedFiles, mode, contractId }
    })

    // ✅ 캐시 무효화 - 트랜잭션 완료 후에 실행
    try {
      // enhanced documents 캐시 무효화
      revalidateTag(`enhanced-documents-${result.contractId}`)
      
      // sync status 관련 캐시도 무효화 (필요시)
      revalidateTag(`sync-status-${result.contractId}`)
      
      console.log(`✅ Cache invalidated for contract ${result.contractId}`)
    } catch (cacheError) {
      console.warn('⚠️ Cache invalidation failed:', cacheError)
      // 캐시 무효화 실패해도 업로드는 성공으로 처리
    }

    return NextResponse.json({
      success: true,
      message: `${result.uploadedFiles.length}개 파일 업로드 완료`,
      data: result,
    })
  } catch (e) {
    console.error("revision-upload error:", e)
    return NextResponse.json(
      { error: "Failed to upload revision", details: String(e) },
      { status: 500 },
    )
  }
}