import React, { useEffect, useCallback } from "react";
import View from "ol/View";

import { EDIT_LAYER_NAME } from "../../defaults";
import { featureToJson } from "../../util";

import MapButton from "./button";

const EditLayerControls = ({ editPath, saveFeature, olLayers, changeTool, setFeatures }) => {
  const clearChanges = useCallback(() => {
    setFeatures(EDIT_LAYER_NAME, []);

    // return the modify tool
    changeTool("Modify", editPath);
  }, [changeTool, setFeatures, editPath]);

  // all done, wrap it up, unload features and the tool
  const done = useCallback(() => {
    setFeatures(EDIT_LAYER_NAME, []);
    changeTool(null);
  }, [setFeatures, changeTool]);

  const saveChanges = useCallback(() => {
    // the edit layer should only ever have one feature!
    const features = olLayers[EDIT_LAYER_NAME].getSource()
      .getFeatures()
      .slice(0, 1)
      .map((f) => featureToJson(f));

    if (features.length > 0) {
      const feature = features[0];
      saveFeature(editPath, feature);
      clearChanges();
    }
  }, [olLayers, saveFeature, clearChanges, editPath]);

  useEffect(() => {
    const keyFn = (evt) => {
      let prevent = false;
      if (evt.key === "Escape") {
        clearChanges();
        prevent = true;
      } else if (evt.key === "s" && evt.ctrlKey) {
        saveChanges();
        prevent = true;
      } else if (evt.key === "x" && evt.ctrlKey) {
        done();
        prevent = true;
      }

      if (prevent) {
        evt.preventDefault();
        evt.stopPropagation();
      }
    };

    document.addEventListener("keydown", keyFn);
    return () => {
      document.removeEventListener("keydown", keyFn);
    };
  }, [clearChanges, saveChanges, done]);

  return (
    <React.Fragment>
      <MapButton label="save-changes" icon="icon save" index={4} onClick={saveChanges} />

      <MapButton disabled label="undo-changes" icon="icon undo" index={3} />

      <MapButton label="cancel-changes" icon="icon cancel" index={2} onClick={clearChanges} />

      <MapButton label="end-drawing" icon="icon stop" index={1} onClick={done} />
    </React.Fragment>
  );
};

const StopControl = ({ changeTool, setFeatures }) => {
  const done = useCallback(() => {
    setFeatures(EDIT_LAYER_NAME, []);
    changeTool(null);
  }, [setFeatures, changeTool]);

  useEffect(() => {
    const keyFn = (evt) => {
      if (evt.key === "Escape") {
        done();
        evt.preventDefault();
        evt.stopPropagation();
      }
    };

    document.addEventListener("keydown", keyFn);
    return () => {
      document.removeEventListener("keydown", keyFn);
    };
  }, [changeTool, done]);

  return <MapButton label="end-drawing" icon="icon stop" index={1} onClick={() => done()} />;
};

const ICON_CLASSES = {
  "draw-point": "point",
  "draw-polygon": "polygon",
  "draw-line": "line",
  "draw-modify": "modify",
  "draw-remove": "remove",
  "draw-edit": "edit",
};

const DRAW_TYPES = {
  "draw-remove": "Remove",
  "draw-modify": "Modify",
  "draw-point": "Point",
  "draw-line": "LineString",
  "draw-polygon": "Polygon",
  "draw-edit": "Edit",
};

const DrawTools = ({ editTools, editPath, setEditPath, setEditTools, changeTool }) => {
  return (
    <React.Fragment>
      {editTools.map((editTool, idx) => (
        <MapButton
          key={editTool}
          label={`${editTool}-tip`}
          icon={`icon ${ICON_CLASSES[editTool]}`}
          index={idx + 2}
          onClick={() => changeTool(DRAW_TYPES[editTool], editPath)}
        />
      ))}

      <MapButton
        label="Close"
        icon="icon close"
        index={editTools.length + 2}
        onClick={() => {
          setEditPath("");
          setEditTools([]);
        }}
      />
    </React.Fragment>
  );
};

const ContextControls = ({
  changeTool,
  editPath,
  editTools,
  saveFeature,
  setFeatures,
  olLayers,
  interactionType,
  activeSource,
  setZoom,
  setEditPath,
  setEditTools,
  zoom,
  resolution,
}) => {
  let controls = false;
  // do not bother rendering anything if the interaction is null
  if (!interactionType && editPath) {
    controls = (
      <DrawTools
        editTools={editTools}
        setEditPath={setEditPath}
        setEditTools={setEditTools}
        changeTool={changeTool}
        editPath={editPath}
      />
    );
  } else if (
    interactionType &&
    interactionType.indexOf("Modify") >= 0 &&
    activeSource === `${EDIT_LAYER_NAME}/${EDIT_LAYER_NAME}`
  ) {
    controls = (
      <EditLayerControls
        olLayers={olLayers}
        changeTool={changeTool}
        saveFeature={saveFeature}
        editPath={editPath}
        setFeatures={setFeatures}
      />
    );
  } else if (interactionType) {
    controls = <StopControl changeTool={changeTool} setFeatures={setFeatures} />;
  }

  const getZoom = () => {
    if (zoom) {
      return zoom;
    }
    return new View().getZoomForResolution(resolution);
  };

  return (
    <React.Fragment>
      <MapButton
        label="zoom-in"
        icon="icon zoom-in"
        index={0}
        onClick={() => setZoom(getZoom() + 1)}
      />

      <MapButton
        label="zoom-out"
        icon="icon zoom-out"
        index={0}
        onClick={() => setZoom(getZoom() - 1)}
      />

      <span style={{ display: "inline-block", width: 16 }}></span>
      {controls}
    </React.Fragment>
  );
};

export default ContextControls;
