12 files changed, 1166 insertions, 0 deletions
diff --git a/Timeline/ClientApp/src/app/common/AlertHost.tsx b/Timeline/ClientApp/src/app/common/AlertHost.tsx
new file mode 100644
index 00000000..89831073
--- /dev/null
+++ b/Timeline/ClientApp/src/app/common/AlertHost.tsx
@@ -0,0 +1,96 @@
+import React, { useCallback } from 'react';
+import { Alert } from 'reactstrap';
+import without from 'lodash/without';
+import concat from 'lodash/concat';
+
+import {
+  alertService,
+  AlertInfoEx,
+  kAlertHostId,
+  AlertInfo,
+} from './alert-service';
+import { useTranslation } from 'react-i18next';
+
+interface AutoCloseAlertProps {
+  alert: AlertInfo;
+  close: () => void;
+}
+
+export const AutoCloseAlert: React.FC<AutoCloseAlertProps> = (props) => {
+  const { alert } = props;
+  const { dismissTime } = alert;
+
+  const { t } = useTranslation();
+
+  React.useEffect(() => {
+    const tag =
+      dismissTime === 'never'
+        ? null
+        : typeof dismissTime === 'number'
+        ? window.setTimeout(props.close, dismissTime)
+        : window.setTimeout(props.close, 5000);
+    return () => {
+      if (tag != null) {
+        window.clearTimeout(tag);
+      }
+    };
+  }, [dismissTime, props.close]);
+
+  return (
+    <Alert className="m-3" color={alert.type ?? 'primary'} toggle={props.close}>
+      {(() => {
+        const { message } = alert;
+        if (typeof message === 'function') {
+          const Message = message;
+          return <Message />;
+        } else if (typeof message === 'object' && message.type === 'i18n') {
+          return t(message.key);
+        } else return alert.message;
+      })()}
+    </Alert>
+  );
+};
+
+// oh what a bad name!
+interface AlertInfoExEx extends AlertInfoEx {
+  close: () => void;
+}
+
+export const AlertHost: React.FC = () => {
+  const [alerts, setAlerts] = React.useState<AlertInfoExEx[]>([]);
+
+  // react guarantee that state setters are stable, so we don't need to add it to dependency list
+
+  const consume = useCallback((alert: AlertInfoEx): void => {
+    const alertEx: AlertInfoExEx = {
+      ...alert,
+      close: () => {
+        setAlerts((oldAlerts) => {
+          return without(oldAlerts, alertEx);
+        });
+      },
+    };
+    setAlerts((oldAlerts) => {
+      return concat(oldAlerts, alertEx);
+    });
+  }, []);
+
+  React.useEffect(() => {
+    alertService.registerConsumer(consume);
+    return () => {
+      alertService.unregisterConsumer(consume);
+    };
+  }, [consume]);
+
+  return (
+    <div id={kAlertHostId} className="alert-container">
+      {alerts.map((alert) => {
+        return (
+          <AutoCloseAlert key={alert.id} alert={alert} close={alert.close} />
+        );
+      })}
+    </div>
+  );
+};
+
+export default AlertHost;
diff --git a/Timeline/ClientApp/src/app/common/AppBar.tsx b/Timeline/ClientApp/src/app/common/AppBar.tsx
new file mode 100644
index 00000000..061ba08c
--- /dev/null
+++ b/Timeline/ClientApp/src/app/common/AppBar.tsx
@@ -0,0 +1,106 @@
+import React from 'react';
+import { useHistory, matchPath } from 'react-router';
+import { Link, NavLink } from 'react-router-dom';
+import { Navbar, NavbarToggler, Collapse, Nav, NavItem } from 'reactstrap';
+import { useMediaQuery } from 'react-responsive';
+import { useTranslation } from 'react-i18next';
+
+import { useUser, useAvatarUrl } from '../data/user';
+
+import TimelineLogo from './TimelineLogo';
+
+const AppBar: React.FC = (_) => {
+  const history = useHistory();
+  const user = useUser();
+  const avatarUrl = useAvatarUrl(user?.username);
+
+  const { t } = useTranslation();
+
+  const isUpMd = useMediaQuery({
+    minWidth: getComputedStyle(document.documentElement).getPropertyValue(
+      '--breakpoint-md'
+    ),
+  });
+
+  const [isMenuOpen, setIsMenuOpen] = React.useState(false);
+
+  const toggleMenu = React.useCallback((): void => {
+    setIsMenuOpen((oldIsMenuOpen) => !oldIsMenuOpen);
+  }, []);
+
+  const isAdministrator = user && user.administrator;
+
+  const rightArea = (
+    <div className="ml-auto mr-2">
+      {user != null ? (
+        <NavLink to={`/users/${user.username}`}>
+          <img
+            className="avatar small rounded-circle bg-white"
+            src={avatarUrl}
+          />
+        </NavLink>
+      ) : (
+        <NavLink className="text-light" to="/login">
+          {t('nav.login')}
+        </NavLink>
+      )}
+    </div>
+  );
+
+  return (
+    <Navbar dark className="fixed-top w-100 bg-primary app-bar" expand="md">
+      <Link to="/" className="navbar-brand d-flex align-items-center">
+        <TimelineLogo style={{ height: '1em' }} />
+        Timeline
+      </Link>
+
+      {isUpMd ? null : rightArea}
+
+      <NavbarToggler onClick={toggleMenu} />
+      <Collapse isOpen={isMenuOpen} navbar>
+        <Nav className="mr-auto" navbar>
+          <NavItem
+            className={
+              matchPath(history.location.pathname, '/settings')
+                ? 'active'
+                : undefined
+            }
+          >
+            <NavLink className="nav-link" to="/settings">
+              {t('nav.settings')}
+            </NavLink>
+          </NavItem>
+
+          <NavItem
+            className={
+              matchPath(history.location.pathname, '/about')
+                ? 'active'
+                : undefined
+            }
+          >
+            <NavLink className="nav-link" to="/about">
+              {t('nav.about')}
+            </NavLink>
+          </NavItem>
+
+          {isAdministrator && (
+            <NavItem
+              className={
+                matchPath(history.location.pathname, '/admin')
+                  ? 'active'
+                  : undefined
+              }
+            >
+              <NavLink className="nav-link" to="/admin">
+                Administration
+              </NavLink>
+            </NavItem>
+          )}
+        </Nav>
+        {isUpMd ? rightArea : null}
+      </Collapse>
+    </Navbar>
+  );
+};
+
+export default AppBar;
diff --git a/Timeline/ClientApp/src/app/common/FileInput.tsx b/Timeline/ClientApp/src/app/common/FileInput.tsx
new file mode 100644
index 00000000..94f4aa43
--- /dev/null
+++ b/Timeline/ClientApp/src/app/common/FileInput.tsx
@@ -0,0 +1,41 @@
+import React from 'react';
+import clsx from 'clsx';
+
+import { ExcludeKey } from '../utilities/type';
+
+export interface FileInputProps
+  extends ExcludeKey<
+    React.InputHTMLAttributes<HTMLInputElement>,
+    'type' | 'id'
+  > {
+  inputId?: string;
+  labelText: string;
+  color?: string;
+  className?: string;
+}
+
+const FileInput: React.FC<FileInputProps> = props => {
+  const { inputId, labelText, color, className, ...otherProps } = props;
+
+  const realInputId = React.useMemo<string>(() => {
+    if (inputId != null) return inputId;
+    return (
+      'file-input-' +
+      (((1 + Math.random()) * 0x10000) | 0).toString(16).substring(1)
+    );
+  }, [inputId]);
+
+  return (
+    <>
+      <input className="d-none" type="file" id={realInputId} {...otherProps} />
+      <label
+        htmlFor={realInputId}
+        className={clsx('btn', 'btn-' + (color ?? 'primary'), className)}
+      >
+        {labelText}
+      </label>
+    </>
+  );
+};
+
+export default FileInput;
diff --git a/Timeline/ClientApp/src/app/common/ImageCropper.tsx b/Timeline/ClientApp/src/app/common/ImageCropper.tsx
new file mode 100644
index 00000000..fb9bb4f9
--- /dev/null
+++ b/Timeline/ClientApp/src/app/common/ImageCropper.tsx
@@ -0,0 +1,306 @@
+import * as React from 'react';
+import clsx from 'clsx';
+
+import { UiLogicError } from '../common';
+
+export interface Clip {
+  left: number;
+  top: number;
+  width: number;
+}
+
+interface NormailizedClip extends Clip {
+  height: number;
+}
+
+interface ImageInfo {
+  width: number;
+  height: number;
+  landscape: boolean;
+  ratio: number;
+  maxClipWidth: number;
+  maxClipHeight: number;
+}
+
+interface ImageCropperSavedState {
+  clip: NormailizedClip;
+  x: number;
+  y: number;
+  pointerId: number;
+}
+
+export interface ImageCropperProps {
+  clip: Clip | null;
+  imageUrl: string;
+  onChange: (clip: Clip) => void;
+  imageElementCallback?: (element: HTMLImageElement | null) => void;
+  className?: string;
+}
+
+const ImageCropper = (props: ImageCropperProps): React.ReactElement => {
+  const { clip, imageUrl, onChange, imageElementCallback, className } = props;
+
+  const [oldState, setOldState] = React.useState<ImageCropperSavedState | null>(
+    null
+  );
+  const [imageInfo, setImageInfo] = React.useState<ImageInfo | null>(null);
+
+  const normalizeClip = (c: Clip | null | undefined): NormailizedClip => {
+    if (c == null) {
+      return { left: 0, top: 0, width: 0, height: 0 };
+    }
+
+    return {
+      left: c.left || 0,
+      top: c.top || 0,
+      width: c.width || 0,
+      height: imageInfo != null ? (c.width || 0) / imageInfo.ratio : 0,
+    };
+  };
+
+  const c = normalizeClip(clip);
+
+  const imgElementRef = React.useRef<HTMLImageElement | null>(null);
+
+  const onImageRef = React.useCallback(
+    (e: HTMLImageElement | null) => {
+      imgElementRef.current = e;
+      if (imageElementCallback != null && e == null) {
+        imageElementCallback(null);
+      }
+    },
+    [imageElementCallback]
+  );
+
+  const onImageLoad = React.useCallback(
+    (e: React.SyntheticEvent<HTMLImageElement>) => {
+      const img = e.currentTarget;
+      const landscape = img.naturalWidth >= img.naturalHeight;
+
+      const info = {
+        width: img.naturalWidth,
+        height: img.naturalHeight,
+        landscape,
+        ratio: img.naturalHeight / img.naturalWidth,
+        maxClipWidth: landscape ? img.naturalHeight / img.naturalWidth : 1,
+        maxClipHeight: landscape ? 1 : img.naturalWidth / img.naturalHeight,
+      };
+      setImageInfo(info);
+      onChange({ left: 0, top: 0, width: info.maxClipWidth });
+      if (imageElementCallback != null) {
+        imageElementCallback(img);
+      }
+    },
+    [onChange, imageElementCallback]
+  );
+
+  const onPointerDown = React.useCallback(
+    (e: React.PointerEvent) => {
+      if (oldState != null) return;
+      e.currentTarget.setPointerCapture(e.pointerId);
+      setOldState({
+        x: e.clientX,
+        y: e.clientY,
+        clip: c,
+        pointerId: e.pointerId,
+      });
+    },
+    [oldState, c]
+  );
+
+  const onPointerUp = React.useCallback(
+    (e: React.PointerEvent) => {
+      if (oldState == null || oldState.pointerId !== e.pointerId) return;
+      e.currentTarget.releasePointerCapture(e.pointerId);
+      setOldState(null);
+    },
+    [oldState]
+  );
+
+  const onPointerMove = React.useCallback(
+    (e: React.PointerEvent) => {
+      if (oldState == null) return;
+
+      const oldClip = oldState.clip;
+
+      const movement = { x: e.clientX - oldState.x, y: e.clientY - oldState.y };
+
+      const { current: imgElement } = imgElementRef;
+
+      if (imgElement == null) throw new UiLogicError('Image element is null.');
+
+      const moveRatio = {
+        x: movement.x / imgElement.width,
+        y: movement.y / imgElement.height,
+      };
+
+      const newRatio = {
+        x: oldClip.left + moveRatio.x,
+        y: oldClip.top + moveRatio.y,
+      };
+      if (newRatio.x < 0) {
+        newRatio.x = 0;
+      } else if (newRatio.x > 1 - oldClip.width) {
+        newRatio.x = 1 - oldClip.width;
+      }
+      if (newRatio.y < 0) {
+        newRatio.y = 0;
+      } else if (newRatio.y > 1 - oldClip.height) {
+        newRatio.y = 1 - oldClip.height;
+      }
+
+      onChange({ left: newRatio.x, top: newRatio.y, width: oldClip.width });
+    },
+    [oldState, onChange]
+  );
+
+  const onHandlerPointerMove = React.useCallback(
+    (e: React.PointerEvent) => {
+      if (oldState == null) return;
+
+      const oldClip = oldState.clip;
+
+      const movement = { x: e.clientX - oldState.x, y: e.clientY - oldState.y };
+
+      const ratio = imageInfo == null ? 1 : imageInfo.ratio;
+
+      const { current: imgElement } = imgElementRef;
+
+      if (imgElement == null) throw new UiLogicError('Image element is null.');
+
+      const moveRatio = {
+        x: movement.x / imgElement.width,
+        y: movement.x / imgElement.width / ratio,
+      };
+
+      const newRatio = {
+        x: oldClip.width + moveRatio.x,
+        y: oldClip.height + moveRatio.y,
+      };
+
+      const maxRatio = {
+        x: Math.min(1 - oldClip.left, newRatio.x),
+        y: Math.min(1 - oldClip.top, newRatio.y),
+      };
+
+      const maxWidthRatio = Math.min(maxRatio.x, maxRatio.y * ratio);
+
+      let newWidth;
+      if (newRatio.x < 0) {
+        newWidth = 0;
+      } else if (newRatio.x > maxWidthRatio) {
+        newWidth = maxWidthRatio;
+      } else {
+        newWidth = newRatio.x;
+      }
+
+      onChange({ left: oldClip.left, top: oldClip.top, width: newWidth });
+    },
+    [imageInfo, oldState, onChange]
+  );
+
+  const toPercentage = (n: number): string => `${n}%`;
+
+  // fuck!!! I just can't find a better way to implement this in pure css
+  const containerStyle: React.CSSProperties = (() => {
+    if (imageInfo == null) {
+      return { width: '100%', paddingTop: '100%', height: 0 };
+    } else {
+      if (imageInfo.ratio > 1) {
+        return {
+          width: toPercentage(100 / imageInfo.ratio),
+          paddingTop: '100%',
+          height: 0,
+        };
+      } else {
+        return {
+          width: '100%',
+          paddingTop: toPercentage(100 * imageInfo.ratio),
+          height: 0,
+        };
+      }
+    }
+  })();
+
+  return (
+    <div
+      className={clsx('image-cropper-container', className)}
+      style={containerStyle}
+    >
+      <img ref={onImageRef} src={imageUrl} onLoad={onImageLoad} alt="to crop" />
+      <div className="image-cropper-mask-container">
+        <div
+          className="image-cropper-mask"
+          touch-action="none"
+          style={{
+            left: toPercentage(c.left * 100),
+            top: toPercentage(c.top * 100),
+            width: toPercentage(c.width * 100),
+            height: toPercentage(c.height * 100),
+          }}
+          onPointerMove={onPointerMove}
+          onPointerDown={onPointerDown}
+          onPointerUp={onPointerUp}
+        />
+      </div>
+      <div
+        className="image-cropper-handler"
+        touch-action="none"
+        style={{
+          left: `calc(${(c.left + c.width) * 100}% - 15px)`,
+          top: `calc(${(c.top + c.height) * 100}% - 15px)`,
+        }}
+        onPointerMove={onHandlerPointerMove}
+        onPointerDown={onPointerDown}
+        onPointerUp={onPointerUp}
+      />
+    </div>
+  );
+};
+
+export default ImageCropper;
+
+export function applyClipToImage(
+  image: HTMLImageElement,
+  clip: Clip,
+  mimeType: string
+): Promise<Blob> {
+  return new Promise((resolve, reject) => {
+    const naturalSize = {
+      width: image.naturalWidth,
+      height: image.naturalHeight,
+    };
+    const clipArea = {
+      x: naturalSize.width * clip.left,
+      y: naturalSize.height * clip.top,
+      length: naturalSize.width * clip.width,
+    };
+
+    const canvas = document.createElement('canvas');
+    canvas.width = clipArea.length;
+    canvas.height = clipArea.length;
+    const context = canvas.getContext('2d');
+
+    if (context == null) throw new Error('Failed to create context.');
+
+    context.drawImage(
+      image,
+      clipArea.x,
+      clipArea.y,
+      clipArea.length,
+      clipArea.length,
+      0,
+      0,
+      clipArea.length,
+      clipArea.length
+    );
+
+    canvas.toBlob((blob) => {
+      if (blob == null) {
+        reject(new Error('canvas.toBlob returns null'));
+      } else {
+        resolve(blob);
+      }
+    }, mimeType);
+  });
+}
diff --git a/Timeline/ClientApp/src/app/common/LoadingPage.tsx b/Timeline/ClientApp/src/app/common/LoadingPage.tsx
new file mode 100644
index 00000000..c1bc7105
--- /dev/null
+++ b/Timeline/ClientApp/src/app/common/LoadingPage.tsx
@@ -0,0 +1,12 @@
+import React from 'react';
+import { Spinner } from 'reactstrap';
+
+const LoadingPage: React.FC = () => {
+  return (
+    <div className="position-fixed w-100 h-100 d-flex justify-content-center align-items-center">
+      <Spinner style={{ height: '2.5rem', width: '2.5rem' }} color="primary" />
+    </div>
+  );
+};
+
+export default LoadingPage;
diff --git a/Timeline/ClientApp/src/app/common/OperationDialog.tsx b/Timeline/ClientApp/src/app/common/OperationDialog.tsx
new file mode 100644
index 00000000..501a353e
--- /dev/null
+++ b/Timeline/ClientApp/src/app/common/OperationDialog.tsx
@@ -0,0 +1,381 @@
+import React, { useState } from 'react';
+import { useTranslation } from 'react-i18next';
+import {
+  Spinner,
+  Container,
+  ModalBody,
+  Label,
+  Input,
+  FormGroup,
+  FormFeedback,
+  ModalFooter,
+  Button,
+  Modal,
+  ModalHeader,
+  FormText,
+} from 'reactstrap';
+
+import { UiLogicError } from '../common';
+
+const DefaultProcessPrompt: React.FC = (_) => {
+  return (
+    <Container className="justify-content-center align-items-center">
+      <Spinner />
+    </Container>
+  );
+};
+
+interface DefaultErrorPromptProps {
+  error?: string;
+}
+
+const DefaultErrorPrompt: React.FC<DefaultErrorPromptProps> = (props) => {
+  const { t } = useTranslation();
+
+  let result = <p className="text-danger">{t('operationDialog.error')}</p>;
+
+  if (props.error != null) {
+    result = (
+      <>
+        {result}
+        <p className="text-danger">{props.error}</p>
+      </>
+    );
+  }
+
+  return result;
+};
+
+export type OperationInputOptionalError = undefined | null | string;
+
+export interface OperationInputErrorInfo {
+  [index: number]: OperationInputOptionalError;
+}
+
+export type OperationInputValidator<TValue> = (
+  value: TValue,
+  values: (string | boolean)[]
+) => OperationInputOptionalError | OperationInputErrorInfo;
+
+export interface OperationTextInputInfo {
+  type: 'text';
+  password?: boolean;
+  label?: string;
+  initValue?: string;
+  textFieldProps?: Omit<
+    React.InputHTMLAttributes<HTMLInputElement>,
+    'type' | 'value' | 'onChange'
+  >;
+  helperText?: string;
+  validator?: OperationInputValidator<string>;
+}
+
+export interface OperationBoolInputInfo {
+  type: 'bool';
+  label: string;
+  initValue?: boolean;
+}
+
+export interface OperationSelectInputInfoOption {
+  value: string;
+  label: string;
+  icon?: React.ReactElement;
+}
+
+export interface OperationSelectInputInfo {
+  type: 'select';
+  label: string;
+  options: OperationSelectInputInfoOption[];
+  initValue?: string;
+}
+
+export type OperationInputInfo =
+  | OperationTextInputInfo
+  | OperationBoolInputInfo
+  | OperationSelectInputInfo;
+
+interface OperationResult {
+  type: 'success' | 'failure';
+  data: unknown;
+}
+
+interface OperationDialogProps {
+  open: boolean;
+  close: () => void;
+  title: React.ReactNode;
+  titleColor?: 'default' | 'dangerous' | 'create' | string;
+  onProcess: (inputs: (string | boolean)[]) => Promise<unknown>;
+  inputScheme?: OperationInputInfo[];
+  inputPrompt?: string | (() => React.ReactNode);
+  processPrompt?: () => React.ReactNode;
+  successPrompt?: (data: unknown) => React.ReactNode;
+  failurePrompt?: (error: unknown) => React.ReactNode;
+  onSuccessAndClose?: () => void;
+}
+
+const OperationDialog: React.FC<OperationDialogProps> = (props) => {
+  const inputScheme = props.inputScheme ?? [];
+
+  const { t } = useTranslation();
+
+  type Step = 'input' | 'process' | OperationResult;
+  const [step, setStep] = useState<Step>('input');
+  const [values, setValues] = useState<(boolean | string)[]>(
+    inputScheme.map((i) => {
+      if (i.type === 'bool') {
+        return i.initValue ?? false;
+      } else if (i.type === 'text' || i.type === 'select') {
+        return i.initValue ?? '';
+      } else {
+        throw new UiLogicError('Unknown input scheme.');
+      }
+    })
+  );
+  const [inputError, setInputError] = useState<OperationInputErrorInfo>({});
+
+  const close = (): void => {
+    if (step !== 'process') {
+      props.close();
+      if (
+        typeof step === 'object' &&
+        step.type === 'success' &&
+        props.onSuccessAndClose
+      ) {
+        props.onSuccessAndClose();
+      }
+    } else {
+      console.log('Attempt to close modal when processing.');
+    }
+  };
+
+  const onConfirm = (): void => {
+    setStep('process');
+    props.onProcess(values).then(
+      (d: unknown) => {
+        setStep({
+          type: 'success',
+          data: d,
+        });
+      },
+      (e: unknown) => {
+        setStep({
+          type: 'failure',
+          data: e,
+        });
+      }
+    );
+  };
+
+  let body: React.ReactNode;
+  if (step === 'input') {
+    let inputPrompt =
+      typeof props.inputPrompt === 'function'
+        ? props.inputPrompt()
+        : props.inputPrompt;
+    inputPrompt = <h6>{inputPrompt}</h6>;
+
+    const updateValue = (
+      index: number,
+      newValue: string | boolean
+    ): (string | boolean)[] => {
+      const oldValues = values;
+      const newValues = oldValues.slice();
+      newValues[index] = newValue;
+      setValues(newValues);
+      return newValues;
+    };
+
+    const testErrorInfo = (errorInfo: OperationInputErrorInfo): boolean => {
+      for (let i = 0; i < inputScheme.length; i++) {
+        if (inputScheme[i].type === 'text' && errorInfo[i] != null) {
+          return true;
+        }
+      }
+      return false;
+    };
+
+    const calculateError = (
+      oldError: OperationInputErrorInfo,
+      index: number,
+      newError: OperationInputOptionalError | OperationInputErrorInfo
+    ): OperationInputErrorInfo => {
+      if (newError === undefined) {
+        return oldError;
+      } else if (newError === null || typeof newError === 'string') {
+        return { ...oldError, [index]: newError };
+      } else {
+        const newInputError: OperationInputErrorInfo = { ...oldError };
+        for (const [index, error] of Object.entries(newError)) {
+          if (error !== undefined) {
+            newInputError[+index] = error as OperationInputOptionalError;
+          }
+        }
+        return newInputError;
+      }
+    };
+
+    const validateAll = (): boolean => {
+      let newInputError = inputError;
+      for (let i = 0; i < inputScheme.length; i++) {
+        const item = inputScheme[i];
+        if (item.type === 'text') {
+          newInputError = calculateError(
+            newInputError,
+            i,
+            item.validator?.(values[i] as string, values)
+          );
+        }
+      }
+      const result = !testErrorInfo(newInputError);
+      setInputError(newInputError);
+      return result;
+    };
+
+    body = (
+      <>
+        <ModalBody>
+          {inputPrompt}
+          {inputScheme.map((item, index) => {
+            const value = values[index];
+            const error: string | undefined = ((e) =>
+              typeof e === 'string' ? t(e) : undefined)(inputError?.[index]);
+
+            if (item.type === 'text') {
+              return (
+                <FormGroup key={index}>
+                  {item.label && <Label>{t(item.label)}</Label>}
+                  <Input
+                    type={item.password === true ? 'password' : 'text'}
+                    value={value as string}
+                    onChange={(e) => {
+                      const v = e.target.value;
+                      const newValues = updateValue(index, v);
+                      setInputError(
+                        calculateError(
+                          inputError,
+                          index,
+                          item.validator?.(v, newValues)
+                        )
+                      );
+                    }}
+                    invalid={error != null}
+                    {...item.textFieldProps}
+                  />
+                  {error != null && <FormFeedback>{error}</FormFeedback>}
+                  {item.helperText && <FormText>{t(item.helperText)}</FormText>}
+                </FormGroup>
+              );
+            } else if (item.type === 'bool') {
+              return (
+                <FormGroup check key={index}>
+                  <Input
+                    type="checkbox"
+                    value={value as string}
+                    onChange={(e) => {
+                      updateValue(
+                        index,
+                        (e.target as HTMLInputElement).checked
+                      );
+                    }}
+                  />
+                  <Label check>{t(item.label)}</Label>
+                </FormGroup>
+              );
+            } else if (item.type === 'select') {
+              return (
+                <FormGroup key={index}>
+                  <Label>{t(item.label)}</Label>
+                  <Input
+                    type="select"
+                    value={value as string}
+                    onChange={(event) => {
+                      updateValue(index, event.target.value);
+                    }}
+                  >
+                    {item.options.map((option, i) => {
+                      return (
+                        <option value={option.value} key={i}>
+                          {option.icon}
+                          {t(option.label)}
+                        </option>
+                      );
+                    })}
+                  </Input>
+                </FormGroup>
+              );
+            }
+          })}
+        </ModalBody>
+        <ModalFooter>
+          <Button color="secondary" onClick={close}>
+            {t('operationDialog.cancel')}
+          </Button>
+          <Button
+            color="primary"
+            disabled={testErrorInfo(inputError)}
+            onClick={() => {
+              if (validateAll()) {
+                onConfirm();
+              }
+            }}
+          >
+            {t('operationDialog.confirm')}
+          </Button>
+        </ModalFooter>
+      </>
+    );
+  } else if (step === 'process') {
+    body = (
+      <ModalBody>
+        {props.processPrompt?.() ?? <DefaultProcessPrompt />}
+      </ModalBody>
+    );
+  } else {
+    let content: React.ReactNode;
+    const result = step;
+    if (result.type === 'success') {
+      content =
+        props.successPrompt?.(result.data) ?? t('operationDialog.success');
+      if (typeof content === 'string')
+        content = <p className="text-success">{content}</p>;
+    } else {
+      content = props.failurePrompt?.(result.data) ?? <DefaultErrorPrompt />;
+      if (typeof content === 'string')
+        content = <DefaultErrorPrompt error={content} />;
+    }
+    body = (
+      <>
+        <ModalBody>{content}</ModalBody>
+        <ModalFooter>
+          <Button color="primary" onClick={close}>
+            {t('operationDialog.ok')}
+          </Button>
+        </ModalFooter>
+      </>
+    );
+  }
+
+  const title = typeof props.title === 'string' ? t(props.title) : props.title;
+
+  return (
+    <Modal isOpen={props.open} toggle={close}>
+      <ModalHeader
+        className={
+          props.titleColor != null
+            ? 'text-' +
+              (props.titleColor === 'create'
+                ? 'success'
+                : props.titleColor === 'dangerous'
+                ? 'danger'
+                : props.titleColor)
+            : undefined
+        }
+      >
+        {title}
+      </ModalHeader>
+      {body}
+    </Modal>
+  );
+};
+
+export default OperationDialog;
diff --git a/Timeline/ClientApp/src/app/common/SearchInput.tsx b/Timeline/ClientApp/src/app/common/SearchInput.tsx
new file mode 100644
index 00000000..46fb00d1
--- /dev/null
+++ b/Timeline/ClientApp/src/app/common/SearchInput.tsx
@@ -0,0 +1,63 @@
+import React, { useCallback } from 'react';
+import clsx from 'clsx';
+import { Spinner, Input, Button } from 'reactstrap';
+import { useTranslation } from 'react-i18next';
+
+export interface SearchInputProps {
+  value: string;
+  onChange: (value: string) => void;
+  onButtonClick: () => void;
+  className?: string;
+  loading?: boolean;
+  buttonText?: string;
+  placeholder?: string;
+  additionalButton?: React.ReactNode;
+}
+
+const SearchInput: React.FC<SearchInputProps> = (props) => {
+  const { onChange, onButtonClick } = props;
+
+  const { t } = useTranslation();
+
+  const onInputChange = useCallback(
+    (event: React.ChangeEvent<HTMLInputElement>): void => {
+      onChange(event.currentTarget.value);
+    },
+    [onChange]
+  );
+
+  const onInputKeyPress = useCallback(
+    (event: React.KeyboardEvent<HTMLInputElement>): void => {
+      if (event.key === 'Enter') {
+        onButtonClick();
+      }
+    },
+    [onButtonClick]
+  );
+
+  return (
+    <div className={clsx('form-inline my-2', props.className)}>
+      <Input
+        className="mr-sm-2"
+        value={props.value}
+        onChange={onInputChange}
+        onKeyPress={onInputKeyPress}
+        placeholder={props.placeholder}
+      />
+      <div className="mt-2 mt-sm-0 order-sm-last ml-sm-3">
+        {props.additionalButton}
+      </div>
+      <div className="mt-2 mt-sm-0 ml-auto ml-sm-0">
+        {props.loading ? (
+          <Spinner />
+        ) : (
+          <Button outline color="primary" onClick={props.onButtonClick}>
+            {props.buttonText ?? t('search')}
+          </Button>
+        )}
+      </div>
+    </div>
+  );
+};
+
+export default SearchInput;
diff --git a/Timeline/ClientApp/src/app/common/TimelineLogo.tsx b/Timeline/ClientApp/src/app/common/TimelineLogo.tsx
new file mode 100644
index 00000000..1ec62021
--- /dev/null
+++ b/Timeline/ClientApp/src/app/common/TimelineLogo.tsx
@@ -0,0 +1,26 @@
+import React, { SVGAttributes } from 'react';
+
+export interface TimelineLogoProps extends SVGAttributes<SVGElement> {
+  color?: string;
+}
+
+const TimelineLogo: React.FC<TimelineLogoProps> = props => {
+  const { color, ...forwardProps } = props;
+  const coercedColor = color ?? 'currentcolor';
+  return (
+    <svg
+      className={props.className}
+      viewBox="0 0 100 100"
+      fill="none"
+      strokeWidth="12"
+      stroke={coercedColor}
+      {...forwardProps}
+    >
+      <line x1="50" y1="0" x2="50" y2="25" />
+      <circle cx="50" cy="50" r="22" />
+      <line x1="50" y1="75" x2="50" y2="100" />
+    </svg>
+  );
+};
+
+export default TimelineLogo;
diff --git a/Timeline/ClientApp/src/app/common/UserTimelineLogo.tsx b/Timeline/ClientApp/src/app/common/UserTimelineLogo.tsx
new file mode 100644
index 00000000..3b721985
--- /dev/null
+++ b/Timeline/ClientApp/src/app/common/UserTimelineLogo.tsx
@@ -0,0 +1,26 @@
+import React, { SVGAttributes } from 'react';
+
+export interface UserTimelineLogoProps extends SVGAttributes<SVGElement> {
+  color?: string;
+}
+
+const UserTimelineLogo: React.FC<UserTimelineLogoProps> = props => {
+  const { color, ...forwardProps } = props;
+  const coercedColor = color ?? 'currentcolor';
+
+  return (
+    <svg viewBox="0 0 100 100" {...forwardProps}>
+      <g fill="none" stroke={coercedColor} strokeWidth="12">
+        <line x1="50" x2="50" y1="0" y2="25" />
+        <circle cx="50" cy="50" r="22" />
+        <line x1="50" x2="50" y1="75" y2="100" />
+      </g>
+      <g fill={color}>
+        <circle cx="85" cy="75" r="10" />
+        <path d="m70,100c0,0 15,-30 30,0.25" />
+      </g>
+    </svg>
+  );
+};
+
+export default UserTimelineLogo;
diff --git a/Timeline/ClientApp/src/app/common/alert-service.ts b/Timeline/ClientApp/src/app/common/alert-service.ts
new file mode 100644
index 00000000..957c5e10
--- /dev/null
+++ b/Timeline/ClientApp/src/app/common/alert-service.ts
@@ -0,0 +1,61 @@
+import React from 'react';
+import pull from 'lodash/pull';
+
+export interface AlertInfo {
+  type?: 'primary' | 'secondary' | 'success' | 'danger' | 'warning' | 'info';
+  message: string | React.FC<unknown> | { type: 'i18n'; key: string };
+  dismissTime?: number | 'never';
+}
+
+export interface AlertInfoEx extends AlertInfo {
+  id: number;
+}
+
+export type AlertConsumer = (alerts: AlertInfoEx) => void;
+
+export class AlertService {
+  private consumers: AlertConsumer[] = [];
+  private savedAlerts: AlertInfoEx[] = [];
+  private currentId = 1;
+
+  private produce(alert: AlertInfoEx): void {
+    for (const consumer of this.consumers) {
+      consumer(alert);
+    }
+  }
+
+  registerConsumer(consumer: AlertConsumer): void {
+    this.consumers.push(consumer);
+    if (this.savedAlerts.length !== 0) {
+      for (const alert of this.savedAlerts) {
+        this.produce(alert);
+      }
+      this.savedAlerts = [];
+    }
+  }
+
+  unregisterConsumer(consumer: AlertConsumer): void {
+    pull(this.consumers, consumer);
+  }
+
+  push(alert: AlertInfo): void {
+    const newAlert: AlertInfoEx = { ...alert, id: this.currentId++ };
+    if (this.consumers.length === 0) {
+      this.savedAlerts.push(newAlert);
+    } else {
+      this.produce(newAlert);
+    }
+  }
+}
+
+export const alertService = new AlertService();
+
+export function pushAlert(alert: AlertInfo): void {
+  alertService.push(alert);
+}
+
+export const kAlertHostId = 'alert-host';
+
+export function getAlertHost(): HTMLElement | null {
+  return document.getElementById(kAlertHostId);
+}
diff --git a/Timeline/ClientApp/src/app/common/alert.sass b/Timeline/ClientApp/src/app/common/alert.sass
new file mode 100644
index 00000000..c3560b87
--- /dev/null
+++ b/Timeline/ClientApp/src/app/common/alert.sass
@@ -0,0 +1,15 @@
+.alert-container
+  position: fixed
+  z-index: $zindex-popover
+
+@include media-breakpoint-up(sm)
+  .alert-container
+    bottom: 0
+    right: 0
+
+@include media-breakpoint-down(sm)
+  .alert-container
+    bottom: 0
+    right: 0
+    left: 0
+    text-align: center
diff --git a/Timeline/ClientApp/src/app/common/common.sass b/Timeline/ClientApp/src/app/common/common.sass
new file mode 100644
index 00000000..78e6fd14
--- /dev/null
+++ b/Timeline/ClientApp/src/app/common/common.sass
@@ -0,0 +1,33 @@
+.image-cropper-container
+  position: relative
+  box-sizing: border-box
+  user-select: none
+
+.image-cropper-container img
+  position: absolute
+  left: 0
+  top: 0
+  width: 100%
+  height: 100%
+
+.image-cropper-mask-container
+  position: absolute
+  left: 0
+  top: 0
+  right: 0
+  bottom: 0
+  overflow: hidden
+
+.image-cropper-mask
+  position: absolute
+  box-shadow: 0 0 0 10000px rgba(255, 255, 255, 80%)
+  touch-action: none
+
+.image-cropper-handler
+  position: absolute
+  width: 26px
+  height: 26px
+  border: black solid 2px
+  border-radius: 50%
+  background: white
+  touch-action: none