import { NextRequest, NextResponse } from "next/server";
import { auth } from "@/auth";
import { db } from "@/lib/db";
import { uploadToHetzner, deleteFromHetzner } from "@/lib/storage";
import { recalcShotStatus } from "@/lib/shot-status";

export const maxDuration = 300; // 5 min — large .mov high-res files

/**
 * POST /api/batch-upload/upload
 *
 * Handles a single file upload from the batch upload flow.
 *
 * FormData fields:
 *   file          – the binary file
 *   action        – "new-version" | "rename-and-upload" | "create-task" | "update-highres"
 *   shotId        – shot DB id (required for all actions)
 *   projectId     – project DB id
 *   taskId        – required for "new-version" and "rename-and-upload"
 *   fallbackTaskId – optional: the "Comp" task id to rename for "create-task"
 *   newTaskTitle  – desired task title (filename without extension)
 */
export async function POST(
  req: NextRequest
): Promise<NextResponse> {
  const session = await auth();
  if (!session?.user) {
    return NextResponse.json({ error: "Unauthorized" }, { status: 401 });
  }

  const formData = await req.formData();
  const file = formData.get("file") as File | null;
  const action = formData.get("action") as string | null;
  const shotId = formData.get("shotId") as string | null;
  const projectId = formData.get("projectId") as string | null;
  const taskId = formData.get("taskId") as string | null;
  const fallbackTaskId = formData.get("fallbackTaskId") as string | null;
  const newTaskTitle = (formData.get("newTaskTitle") as string | null) ?? "";

  if (!file || !action || !shotId || !projectId) {
    return NextResponse.json(
      { error: "Missing required fields: file, action, shotId, projectId" },
      { status: 400 }
    );
  }

  const buffer = Buffer.from(await file.arrayBuffer());

  // Browsers (especially on Windows) often send an empty MIME type for .mov
  // files. Fall back to a safe content type based on the file extension.
  const ext = file.name.split(".").pop()?.toLowerCase();
  const contentType =
    file.type ||
    (ext === "mov" ? "video/quicktime" :
     ext === "mp4" ? "video/mp4" :
     "application/octet-stream");

  // ── High-res (.mov) ───────────────────────────────────────────────────────
  if (action === "update-highres") {
    const shot = await db.shot.findUnique({
      where: { id: shotId },
      select: { id: true, highResKey: true },
    });
    if (!shot) {
      return NextResponse.json({ error: "Shot not found" }, { status: 404 });
    }

    // Remove the previous high-res file if one exists
    if (shot.highResKey) {
      await deleteFromHetzner(shot.highResKey).catch(() => {});
    }

    const { key } = await uploadToHetzner(buffer, file.name, contentType, "highres");

    await db.shot.update({
      where: { id: shotId },
      data: { highResKey: key, highResFilename: file.name },
    });

    return NextResponse.json({
      success: true,
      action: "update-highres",
      fileName: file.name,
    });
  }

  // ── Version upload (.mp4) ─────────────────────────────────────────────────
  let resolvedTaskId: string;

  if (action === "new-version") {
    if (!taskId) {
      return NextResponse.json(
        { error: "taskId is required for new-version action" },
        { status: 400 }
      );
    }
    resolvedTaskId = taskId;
  } else if (action === "rename-and-upload") {
    if (!taskId) {
      return NextResponse.json(
        { error: "taskId is required for rename-and-upload action" },
        { status: 400 }
      );
    }
    // Rename the task to reflect the new version number
    await db.task.update({
      where: { id: taskId },
      data: { title: newTaskTitle },
    });
    resolvedTaskId = taskId;
  } else if (action === "create-task") {
    if (fallbackTaskId) {
      // Rename the existing "Comp" (or similar) task and reuse it
      await db.task.update({
        where: { id: fallbackTaskId },
        data: { title: newTaskTitle },
      });
      resolvedTaskId = fallbackTaskId;
    } else {
      // Create a brand-new task under the shot
      const lastTask = await db.task.findFirst({
        where: { shotId },
        orderBy: { sortOrder: "desc" },
        select: { sortOrder: true },
      });
      const task = await db.task.create({
        data: {
          title: newTaskTitle,
          type: "COMP",
          shotId,
          projectId,
          createdById: session.user.id,
          sortOrder: (lastTask?.sortOrder ?? -1) + 1,
        },
      });
      resolvedTaskId = task.id;
    }
  } else {
    return NextResponse.json(
      { error: `Unknown action: ${action}` },
      { status: 400 }
    );
  }

  // Upload the video to Hetzner object storage
  const { key: videoKey } = await uploadToHetzner(buffer, file.name, contentType, "videos");
  const result = { url: `/api/files/${videoKey}`, key: videoKey };

  // Mark all existing versions for this task as no longer latest
  await db.version.updateMany({
    where: { taskId: resolvedTaskId },
    data: { isLatest: false },
  });

  // Determine next sequential version number
  const lastVersion = await db.version.findFirst({
    where: { taskId: resolvedTaskId },
    orderBy: { versionNumber: "desc" },
    select: { versionNumber: true },
  });
  const versionNumber = (lastVersion?.versionNumber ?? 0) + 1;

  // Create the version record
  const version = await db.version.create({
    data: {
      versionNumber,
      taskId: resolvedTaskId,
      artistId: session.user.id,
      fileUrl: result.url,
      fileName: file.name,
      fileSize: BigInt(file.size),
      mimeType: file.type,
      isLatest: true,
    },
  });

  // Move the task to INTERNAL_REVIEW
  await db.task.update({
    where: { id: resolvedTaskId },
    data: { status: "INTERNAL_REVIEW" },
  });

  // Recalculate the parent shot's status
  await recalcShotStatus(shotId).catch(() => {});

  return NextResponse.json({
    success: true,
    action,
    versionId: version.id,
    versionNumber,
    taskId: resolvedTaskId,
  });
}