//
//  AttachMediaUtility.swift
//  damus
//
//  Created by Swift on 2/17/23.
//

import SwiftUI
import UIKit
import CoreGraphics
import UniformTypeIdentifiers

enum ImageUploadResult {
    case success(String)
    case failed(Error?)
}

fileprivate func create_upload_body(mediaData: Data, boundary: String, mediaUploader: MediaUploader, mediaToUpload: MediaUpload) -> Data {
        let body = NSMutableData();
        let contentType = mediaToUpload.mime_type
        body.appendString(string: "Content-Type: multipart/form-data; boundary=\(boundary)\r\n\r\n")
        body.appendString(string: "--\(boundary)\r\n")
        body.appendString(string: "Content-Disposition: form-data; name=\(mediaUploader.nameParam); filename=\(mediaToUpload.genericFileName)\r\n")
        body.appendString(string: "Content-Type: \(contentType)\r\n\r\n")
        body.append(mediaData as Data)
        body.appendString(string: "\r\n")
        body.appendString(string: "--\(boundary)--\r\n")
        return body as Data
    }

func create_upload_request(mediaToUpload: MediaUpload, mediaUploader: MediaUploader, progress: URLSessionTaskDelegate, keypair: Keypair? = nil) async -> ImageUploadResult {
    var mediaData: Data?
    guard let url = URL(string: mediaUploader.postAPI) else {
        return .failed(nil)
    }
    
    var request = URLRequest(url: url)
    request.httpMethod = "POST";
    let boundary = "Boundary-\(UUID().description)"
    request.setValue("multipart/form-data; boundary=\(boundary)", forHTTPHeaderField: "Content-Type")
    
    // If uploading to a media host that support NIP-98 authorization, add the header
    if mediaUploader == .nostrBuild || mediaUploader == .nostrcheck,
       let keypair,
        let method = request.httpMethod,
        let signature = create_nip98_signature(keypair: keypair, method: method, url: url) {

         request.setValue(signature, forHTTPHeaderField: "Authorization")
    }
    
    switch mediaToUpload {
    case .image(let url):
        do {
            mediaData = try Data(contentsOf: url)
        } catch {
            return .failed(error)
        }
    case .video(let url):
        do {
            mediaData = try Data(contentsOf: url)
        } catch {
            return .failed(error)
        }
    }

    guard let mediaData else {
        return .failed(nil)
    }

    request.httpBody = create_upload_body(mediaData: mediaData, boundary: boundary, mediaUploader: mediaUploader, mediaToUpload: mediaToUpload)
    
    do {
        let (data, _) = try await URLSession.shared.data(for: request, delegate: progress)

        guard let url = mediaUploader.getMediaURL(from: data) else {
            print("Upload failed getting media url")
            return .failed(nil)
        }
        
        return .success(url)
        
    } catch {
        return .failed(error)
    }
}

extension NSMutableData {
    func appendString(string: String) {
        guard let data = string.data(using: String.Encoding.utf8, allowLossyConversion: true) else {
            return
        }
        append(data)
    }
}