/***********************************************************************************************************************************************************************
 * File Name: task_upload.controller.js  (client)
 * Type of Program: Controller
 * Description: Handles file uploads for task completion attachments.
 *              Files are uploaded to S3 (Garage) via s3.service.js.
 *              Returns file metadata for use in the completion submit payload.
 *
 *              This is intentionally separate from the completion submit endpoint
 *              so the client can upload files first, then submit completion with
 *              the returned file references — matching the two-step flow in
 *              ViewTaskDetails.jsx handleSubmit().
 *
 * Route: POST /client/groups/:groupId/task-lists/:taskListId/tasks/:taskId/upload
 *
 * Author: rgrgogu
 * Date Created: Jun. 13, 2026
 ***********************************************************************************************************************************************************************/
const { Task, TaskList, TaskListGroup } = require('../../models/task/task.mdl');
const { mdl_UserGroups, mdl_UserGroupMembers } = require('../../models/users/user_groups.mdl');
const { uploadFile } = require('../../services/s3.service');
const R = require('../../utils/response.util');

// ─── Helper: verify user is a member of the group ─────────────────────────────
const isMember = async (userId, groupId) => {
    const membership = await mdl_UserGroupMembers.findOne({
        where: { user_id: userId, group_id: groupId, deletedAt: null },
    });
    return !!membership;
};

// ─── Helper: verify task belongs to task list AND is assigned to this group ───
const getAccessibleTask = async (groupId, taskListId, taskId) => {
    return Task.findOne({
        where: { task_id: taskId, task_list_id: taskListId },
        include: [
            {
                model: TaskList,
                as: 'taskList',
                required: true,
                include: [
                    {
                        model: mdl_UserGroups,
                        as: 'groups',
                        where: { group_id: groupId },
                        required: true,
                        attributes: [],
                        through: { model: TaskListGroup, attributes: [] },
                    },
                ],
            },
        ],
    });
};

// ─── Resolve S3 ownerType from mime type ──────────────────────────────────────
const resolveOwnerType = (mimetype = '') => {
    if (mimetype.startsWith('image/'))  return 'image';
    if (mimetype.startsWith('video/'))  return 'video';
    if (mimetype.startsWith('audio/'))  return 'audio';
    return 'document';
};

// =============================================================================
// ── UPLOAD FILE ───────────────────────────────────────────────────────────────
// =============================================================================

// POST /client/groups/:groupId/task-lists/:taskListId/tasks/:taskId/upload
//
// Accepts: multipart/form-data
//   file  — single file field (multer attaches to req.file)
//
// Returns:
// {
//   file_url  : "https://cdn.yourdomain.com/your-bucket/documents/uuid.pdf",
//   file_name : "social_media_slides.pdf",
//   file_size : 2400000,
//   mime_type : "application/pdf",
//   storage_key: "documents/uuid.pdf"   ← for admin reference / future delete
// }

exports.uploadTaskFile = async (req, res) => {
    try {
        const { groupId, taskListId, taskId } = req.params;

        // ── Validate member ───────────────────────────────────────────────────
        const member = await isMember(req.user.user_id, groupId);
        if (!member) return R.error(res, 'Group not found or you are not a member.', 403);

        // ── Validate task accessibility ───────────────────────────────────────
        const task = await getAccessibleTask(groupId, taskListId, taskId);
        if (!task) return R.error(res, 'Task not found or not accessible.', 404);

        // ── Validate file presence ────────────────────────────────────────────
        if (!req.file) return R.error(res, 'No file provided.', 400);

        const { buffer, originalname, mimetype, size } = req.file;
        const ownerType = resolveOwnerType(mimetype);

        // ── Upload to S3 ──────────────────────────────────────────────────────
        const { url, uuid: storage_key } = await uploadFile({
            buffer,
            originalname,
            mimetype,
            ownerType,
        });

        return R.success(res, 'File uploaded successfully.', {
            file_url:    url,
            file_name:   originalname,
            file_size:   size,
            mime_type:   mimetype,
            storage_key,
        }, 201);
    } catch (err) {
        console.error('[CLIENT][UPLOAD TASK FILE]', err);
        return R.error(res, 'Could not upload file.', 500);
    }
};