import React from "react";
import clsx from "clsx";
import { useTranslation } from "react-i18next";
import Svg from "react-inlinesvg";
import { Button, Spinner, Row, Col, Form } from "react-bootstrap";
import textIcon from "bootstrap-icons/icons/card-text.svg";
import imageIcon from "bootstrap-icons/icons/image.svg";

import { UiLogicError } from "@/common";

import { pushAlert } from "@/services/alert";
import { TimelineCreatePostRequest } from "@/services/timeline";

interface TimelinePostEditImageProps {
  onSelect: (blob: Blob | null) => void;
}

const TimelinePostEditImage: React.FC<TimelinePostEditImageProps> = (props) => {
  const { onSelect } = props;
  const { t } = useTranslation();

  const [file, setFile] = React.useState<File | null>(null);
  const [fileUrl, setFileUrl] = React.useState<string | null>(null);
  const [error, setError] = React.useState<string | null>(null);

  React.useEffect(() => {
    if (file != null) {
      const url = URL.createObjectURL(file);
      setFileUrl(url);
      return () => {
        URL.revokeObjectURL(url);
      };
    }
  }, [file]);

  const onInputChange: React.ChangeEventHandler<HTMLInputElement> = React.useCallback(
    (e) => {
      const files = e.target.files;
      if (files == null || files.length === 0) {
        setFile(null);
        setFileUrl(null);
      } else {
        setFile(files[0]);
      }
      onSelect(null);
      setError(null);
    },
    [onSelect]
  );

  const onImgLoad = React.useCallback(() => {
    onSelect(file);
  }, [onSelect, file]);

  const onImgError = React.useCallback(() => {
    setError("loadImageError");
  }, []);

  return (
    <>
      <Form.File
        label={t("chooseImage")}
        onChange={onInputChange}
        accept="image/*"
        className="mx-3 my-1 d-inline-block"
      />
      {fileUrl && error == null && (
        <img
          src={fileUrl}
          className="timeline-post-edit-image"
          onLoad={onImgLoad}
          onError={onImgError}
        />
      )}
      {error != null && <div className="text-danger">{t(error)}</div>}
    </>
  );
};

export type TimelinePostSendCallback = (
  content: TimelineCreatePostRequest
) => Promise<void>;

export interface TimelinePostEditProps {
  className?: string;
  onPost: TimelinePostSendCallback;
  onHeightChange?: (height: number) => void;
  timelineUniqueId: string;
}

const TimelinePostEdit: React.FC<TimelinePostEditProps> = (props) => {
  const { onPost } = props;

  const { t } = useTranslation();

  const [state, setState] = React.useState<"input" | "process">("input");
  const [kind, setKind] = React.useState<"text" | "image">("text");
  const [text, setText] = React.useState<string>("");
  const [imageBlob, setImageBlob] = React.useState<Blob | null>(null);

  const draftLocalStorageKey = `timeline.${props.timelineUniqueId}.postDraft`;

  React.useEffect(() => {
    setText(window.localStorage.getItem(draftLocalStorageKey) ?? "");
  }, [draftLocalStorageKey]);

  const canSend = kind === "text" || (kind === "image" && imageBlob != null);

  // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
  const containerRef = React.useRef<HTMLDivElement>(null!);

  const notifyHeightChange = (): void => {
    if (props.onHeightChange) {
      props.onHeightChange(containerRef.current.clientHeight);
    }
  };

  React.useEffect(() => {
    if (props.onHeightChange) {
      props.onHeightChange(containerRef.current.clientHeight);
    }
    return () => {
      if (props.onHeightChange) {
        props.onHeightChange(0);
      }
    };
  });

  const toggleKind = React.useCallback(() => {
    setKind((oldKind) => (oldKind === "text" ? "image" : "text"));
    setImageBlob(null);
  }, []);

  const onSend = React.useCallback(() => {
    setState("process");

    const req: TimelineCreatePostRequest = (() => {
      switch (kind) {
        case "text":
          return {
            content: {
              type: "text",
              text: text,
            },
          } as TimelineCreatePostRequest;
        case "image":
          if (imageBlob == null) {
            throw new UiLogicError(
              "Content type is image but image blob is null."
            );
          }
          return {
            content: {
              type: "image",
              data: imageBlob,
            },
          } as TimelineCreatePostRequest;
        default:
          throw new UiLogicError("Unknown content type.");
      }
    })();

    onPost(req).then(
      (_) => {
        if (kind === "text") {
          setText("");
          window.localStorage.removeItem(draftLocalStorageKey);
        }
        setState("input");
        setKind("text");
      },
      (_) => {
        pushAlert({
          type: "danger",
          message: t("timeline.sendPostFailed"),
        });
        setState("input");
      }
    );
  }, [onPost, kind, text, imageBlob, t, draftLocalStorageKey]);

  const onImageSelect = React.useCallback((blob: Blob | null) => {
    setImageBlob(blob);
  }, []);

  return (
    <div
      ref={containerRef}
      className={clsx("container-fluid bg-light", props.className)}
    >
      <Row>
        <Col className="px-1 py-1">
          {kind === "text" ? (
            <Form.Control
              as="textarea"
              className="w-100 h-100 timeline-post-edit"
              value={text}
              disabled={state === "process"}
              onChange={(event: React.ChangeEvent<HTMLTextAreaElement>) => {
                const value = event.currentTarget.value;
                setText(value);
                window.localStorage.setItem(draftLocalStorageKey, value);
              }}
            />
          ) : (
            <TimelinePostEditImage onSelect={onImageSelect} />
          )}
        </Col>
        <Col xs="auto" className="align-self-end m-1">
          {(() => {
            if (state === "input") {
              return (
                <>
                  <div className="d-block text-center mt-1 mb-2">
                    <Svg
                      onLoad={notifyHeightChange}
                      src={kind === "text" ? imageIcon : textIcon}
                      className="icon-button"
                      onClick={toggleKind}
                    />
                  </div>
                  <Button
                    variant="primary"
                    onClick={onSend}
                    disabled={!canSend}
                  >
                    {t("timeline.send")}
                  </Button>
                </>
              );
            } else {
              return <Spinner variant="primary" animation="border" />;
            }
          })()}
        </Col>
      </Row>
    </div>
  );
};

export default TimelinePostEdit;