@Slf4j
@RestController
@RequiredArgsConstructor
@RequestMapping(path = "api/tasks")
final class TasksController {

    private final StorageService storageService;
    private final TasksService tasksService;
    private final TasksConfig config;

    @PostConstruct
    private void init() {
        tasksService.addTask("Jarek", "DO APP", "Prepare application");
        tasksService.addTask("Jarek", "LEARN", "Refresh multithreading knowledge. Learn about monads");
        tasksService.addTask("Guest", "Test", "Test guest task");
    }

    @GetMapping
    public ResponseEntity getTasks(@RequestParam Optional<String> query) {
        log.info("Fetching all tasks with filter: {}", query);
        List<TaskResponse> tasks = query.map(tasksService::filterAllByQuery)
                .orElseGet(tasksService::fetchAll)
                .stream()
                .map(this::toTaskResponse)
                .collect(toList());
        return ResponseEntity.ok(tasks);
    }

    @GetMapping(path = "/{id}")
    public ResponseEntity getTaskById(@PathVariable Long id) {
        log.info("Fetching task with id: {}", id);
        return ResponseEntity.ok(tasksService.fetchById(id));
    }

    @PostMapping
    public ResponseEntity addTask(@RequestBody CreateTaskRequest task) {
        log.info("Storing new task {}", task);
        tasksService.addTask(task.getAuthor(), task.getTitle(), task.getDescription());
        return ResponseEntity.status(HttpStatus.CREATED).build();
    }

    @DeleteMapping(path = "/{id}")
    public ResponseEntity deleteTask(@PathVariable Long id) {
        log.info("Deleting a task with id: {}", id);
        tasksService.deleteTask(id);
        return ResponseEntity.ok().build();
    }

    @PutMapping(path = "/{id}")
    public ResponseEntity<String> updateTask(@PathVariable Long id, @RequestBody UpdateTaskRequest request) {
        log.info("Updating a task with id: {}", id);
        tasksService.updateTask(id, request.getTitle(), request.getDescription());
        return ResponseEntity.ok().build();
    }

    @GetMapping(path = "/{id}/attachments/{filename}")
    public ResponseEntity getAttachment(
            @PathVariable Long id,
            @PathVariable String filename,
            HttpServletRequest request) throws IOException {
        log.info("Fetching attachment: {}, from task with id: {}", filename, id);
        Resource resource = storageService.loadFile(id, filename);
        String mimeType = request.getServletContext().getMimeType(resource.getFile().getAbsolutePath());
        if (mimeType == null) {
            mimeType = "application/octet-stream";
        }
        return ResponseEntity.ok()
                .contentType(MediaType.parseMediaType(mimeType))
                .body(resource);
    }

    @PostMapping(path = "/{id}/attachments")
    public ResponseEntity addAttachment(@PathVariable Long id, @RequestParam("file") MultipartFile file) throws IOException {
        log.info("Saving attachment: {}, to task with id: {}", file.getName(), id);
        Task task = tasksService.fetchById(id);
        task.getAttachments().add(file.getOriginalFilename());
        storageService.saveFile(id, file);
        return ResponseEntity.status(HttpStatus.CREATED).build();
    }

    @GetMapping(path = "/hello")
    public String hello() {
        return config.getEndpointMessage();
    }

    private TaskResponse toTaskResponse(Task task) {
        return new TaskResponse(
                task.getId(),
                task.getTitle(),
                task.getAuthor(),
                task.getDescription(),
                task.getCreatedAt(),
                task.getAttachments());
    }
}