import React, { useCallback, useRef, useEffect, useState } from "react";
import { useRouter } from "next/router";
import Gradient from "javascript-color-gradient";
import mapboxgl from "mapbox-gl";
import useSWRImmutable from "swr/immutable";

import styles from "../styles/Map.module.css";
import Sidebar from "./Sidebar";
import ToggleLayersControl from "./ToggleLayersControl";
import SearchBar from "./SearchBar";

mapboxgl.accessToken = process.env.NEXT_PUBLIC_MAPBOX_TOKEN ?? "";

const colorGradient = new Gradient();
colorGradient.setGradient(
  "#0000FF",
  "#00FF00",
  "#FFFF00",
  "#FFA500",
  "#FF0000"
);
colorGradient.setMidpoint(360);

const LIVE_DOWNLOAD_COUNTS_URL =
  "https://staticstats.nexusmods.com/live_download_counts/mods/1704.csv";

const jsonFetcher = (url: string) => fetch(url).then((res) => res.json());
const csvFetcher = (url: string) => fetch(url).then((res) => res.text());

const Map: React.FC = () => {
  const router = useRouter();
  const mapContainer = useRef<HTMLDivElement | null>(
    null
  ) as React.MutableRefObject<HTMLDivElement>;
  const map = useRef<mapboxgl.Map | null>(
    null
  ) as React.MutableRefObject<mapboxgl.Map>;
  const mapWrapper = useRef<HTMLDivElement | null>(
    null
  ) as React.MutableRefObject<HTMLDivElement>;

  const [mapLoaded, setMapLoaded] = useState<boolean>(false);
  const [heatmapLoaded, setHeatmapLoaded] = useState<boolean>(false);
  const [selectedCell, setSelectedCell] = useState<{
    x: number;
    y: number;
  } | null>(null);
  const [selectedCells, setSelectedCells] = useState<
    | {
        x: number;
        y: number;
      }[]
    | null
  >(null);
  const sidebarOpen = selectedCell !== null || router.query.mod !== undefined;

  const { data: cellsData, error: cellsError } = useSWRImmutable(
    "https://cells.modmapper.com/edits.json",
    jsonFetcher
  );
  // The live download counts are not really immutable, but I'd still rather load them once per session
  const [counts, setCounts] = useState<Record<
    number,
    [number, number, number]
  > | null>(null);
  const { data: countsData, error: countsError } = useSWRImmutable(
    LIVE_DOWNLOAD_COUNTS_URL,
    csvFetcher
  );

  const selectMapCell = useCallback(
    (cell: { x: number; y: number }) => {
      if (!map.current) return;
      if (map.current && !map.current.getSource("grid-source")) return;

      map.current.setFeatureState(
        {
          source: "grid-source",
          id: (cell.x + 57) * 100 + 50 - cell.y,
        },
        {
          selected: true,
        }
      );
      requestAnimationFrame(() => map.current && map.current.resize());

      var zoom = map.current.getZoom();
      var viewportNW = map.current.project([-180, 85.051129]);
      var cellSize = Math.pow(2, zoom + 2);
      const x = cell.x + 57;
      const y = 50 - cell.y;
      let nw = map.current.unproject([
        x * cellSize + viewportNW.x,
        y * cellSize + viewportNW.y,
      ]);
      let ne = map.current.unproject([
        x * cellSize + viewportNW.x + cellSize,
        y * cellSize + viewportNW.y,
      ]);
      let se = map.current.unproject([
        x * cellSize + viewportNW.x + cellSize,
        y * cellSize + viewportNW.y + cellSize,
      ]);
      let sw = map.current.unproject([
        x * cellSize + viewportNW.x,
        y * cellSize + viewportNW.y + cellSize,
      ]);
      const selectedCellLines: GeoJSON.FeatureCollection<
        GeoJSON.Geometry,
        GeoJSON.GeoJsonProperties
      > = {
        type: "FeatureCollection",
        features: [
          {
            type: "Feature",
            geometry: {
              type: "LineString",
              coordinates: [
                [nw.lng, nw.lat],
                [ne.lng, ne.lat],
                [se.lng, se.lat],
                [sw.lng, sw.lat],
                [nw.lng, nw.lat],
              ],
            },
            properties: { x: x, y: y },
          },
        ],
      };

      if (map.current.getLayer("selected-cell-layer")) {
        map.current.removeLayer("selected-cell-layer");
      }
      if (map.current.getSource("selected-cell-source")) {
        map.current.removeSource("selected-cell-source");
      }
      map.current.addSource("selected-cell-source", {
        type: "geojson",
        data: selectedCellLines,
      });
      map.current.addLayer({
        id: "selected-cell-layer",
        type: "line",
        source: "selected-cell-source",
        paint: {
          "line-color": "blue",
          "line-width": 3,
        },
      });

      const bounds = map.current.getBounds();
      if (!bounds.contains(nw) || !bounds.contains(se)) {
        map.current.panTo(nw);
      }
    },
    [map]
  );

  const selectCells = useCallback(
    (cells: { x: number; y: number }[]) => {
      if (!map.current) return;
      if (map.current && !map.current.getSource("grid-source")) return;

      var zoom = map.current.getZoom();
      var viewportNW = map.current.project([-180, 85.051129]);
      var cellSize = Math.pow(2, zoom + 2);

      const selectedCellsLines: GeoJSON.FeatureCollection<
        GeoJSON.Geometry,
        GeoJSON.GeoJsonProperties
      > = {
        type: "FeatureCollection",
        features: [],
      };
      let bounds: mapboxgl.LngLatBounds | null = null;

      for (const cell of cells) {
        const x = cell.x + 57;
        const y = 50 - cell.y;
        let nw = map.current.unproject([
          x * cellSize + viewportNW.x,
          y * cellSize + viewportNW.y,
        ]);
        let ne = map.current.unproject([
          x * cellSize + viewportNW.x + cellSize,
          y * cellSize + viewportNW.y,
        ]);
        let se = map.current.unproject([
          x * cellSize + viewportNW.x + cellSize,
          y * cellSize + viewportNW.y + cellSize,
        ]);
        let sw = map.current.unproject([
          x * cellSize + viewportNW.x,
          y * cellSize + viewportNW.y + cellSize,
        ]);
        if (bounds) {
          bounds.extend(new mapboxgl.LngLatBounds(sw, ne));
        } else {
          bounds = new mapboxgl.LngLatBounds(sw, ne);
        }
        selectedCellsLines.features.push({
          type: "Feature",
          geometry: {
            type: "LineString",
            coordinates: [
              [nw.lng, nw.lat],
              [ne.lng, ne.lat],
              [se.lng, se.lat],
              [sw.lng, sw.lat],
              [nw.lng, nw.lat],
            ],
          },
          properties: { x: x, y: y },
        });
      }

      if (map.current.getLayer("selected-cells-layer")) {
        map.current.removeLayer("selected-cells-layer");
      }
      if (map.current.getSource("selected-cells-source")) {
        map.current.removeSource("selected-cells-source");
      }
      map.current.addSource("selected-cells-source", {
        type: "geojson",
        data: selectedCellsLines,
      });
      map.current.addLayer({
        id: "selected-cells-layer",
        type: "line",
        source: "selected-cells-source",
        paint: {
          "line-color": "purple",
          "line-width": 4,
        },
      });

      requestAnimationFrame(() => {
        if (map.current) {
          map.current.resize();
          if (bounds) {
            map.current.fitBounds(bounds, { padding: 20 });
          }
        }
      });
    },
    [map]
  );

  const selectCell = useCallback(
    (cell) => {
      router.push({ query: { cell: cell.x + "," + cell.y } });
      setSelectedCell(cell);
      selectMapCell(cell);
    },
    [setSelectedCell, selectMapCell, router]
  );

  const clearSelectedCell = useCallback(() => {
    setSelectedCell(null);
    if (map.current) map.current.removeFeatureState({ source: "grid-source" });
    if (map.current && map.current.getLayer("selected-cell-layer")) {
      map.current.removeLayer("selected-cell-layer");
    }
    if (map.current && map.current.getSource("selected-cell-source")) {
      map.current.removeSource("selected-cell-source");
    }
    requestAnimationFrame(() => {
      if (map.current) map.current.resize();
    });
  }, [map]);

  const clearSelectedCells = useCallback(() => {
    setSelectedCells(null);
    if (map.current && map.current.getLayer("selected-cells-layer")) {
      map.current.removeLayer("selected-cells-layer");
    }
    if (map.current && map.current.getSource("selected-cells-source")) {
      map.current.removeSource("selected-cells-source");
    }
    requestAnimationFrame(() => {
      if (map.current) map.current.resize();
    });
  }, [map]);

  const clearSelectedMod = useCallback(() => {
    requestAnimationFrame(() => {
      if (map.current) map.current.resize();
    });
  }, [map]);

  useEffect(() => {
    if (!heatmapLoaded) return; // wait for all map layers to load
    if (router.query.cell && typeof router.query.cell === "string") {
      const cellUrlParts = decodeURIComponent(router.query.cell).split(",");
      const cell = {
        x: parseInt(cellUrlParts[0]),
        y: parseInt(cellUrlParts[1]),
      };
      if (
        !selectedCell ||
        selectedCell.x !== cell.x ||
        selectedCell.y !== cell.y
      ) {
        selectCell(cell);
      }
    } else {
      if (selectedCell) {
        clearSelectedCell();
      }
    }
  }, [
    selectedCell,
    router.query.cell,
    router.query.mod,
    selectCell,
    clearSelectedCell,
    heatmapLoaded,
  ]);

  useEffect(() => {
    if (!heatmapLoaded) return; // wait for all map layers to load
    if (
      router.query.mod &&
      typeof router.query.mod === "string" &&
      selectedCells
    ) {
      selectCells(selectedCells);
    } else {
      if (selectedCells) {
        clearSelectedCells();
      }
    }
  }, [
    selectedCells,
    router.query.mod,
    selectCells,
    clearSelectedCells,
    heatmapLoaded,
  ]);

  useEffect(() => {
    if (!heatmapLoaded) return; // wait for all map layers to load
    if (!router.query.mod || typeof router.query.mod !== "string") {
      clearSelectedMod();
    }
  }, [router.query.mod, clearSelectedMod, heatmapLoaded]);

  useEffect(() => {
    if (map.current) return; // initialize map only once
    map.current = new mapboxgl.Map({
      container: mapContainer.current,
      style: {
        version: 8,
        sources: {
          "raster-tiles": {
            type: "raster",
            tiles: ["https://tiles.modmapper.com/{z}/{x}/{y}.jpg"],
            tileSize: 256,
            attribution:
              'Map tiles by <a href="https://en.uesp.net/wiki/Skyrim:Skyrim" target="_blank">UESP</a>. Mod data from <a href="https://nexusmods.com" target="_blank">Nexus Mods</a>.',
          },
        },
        layers: [
          {
            id: "simple-tiles",
            type: "raster",
            source: "raster-tiles",
          },
        ],
        glyphs: "mapbox://fonts/mapbox/{fontstack}/{range}.pbf",
      },
      center: [0, 0],
      zoom: 0,
      minZoom: 0,
      maxZoom: 8,
      maxBounds: [
        [-180, -85.051129],
        [180, 85.051129],
      ],
    });
    map.current.on("load", () => {
      setMapLoaded(true);
    });
  }, [setMapLoaded]);

  useEffect(() => {
    if (!cellsData || !router.isReady || !mapLoaded) return; // wait for map to initialize and data to load
    if (map.current.getSource("graticule")) return; // don't initialize twice

    const zoom = map.current.getZoom();
    const viewportNW = map.current.project([-180, 85.051129]);
    const cellSize = Math.pow(2, zoom + 2);

    const graticule: GeoJSON.FeatureCollection<
      GeoJSON.Geometry,
      GeoJSON.GeoJsonProperties
    > = {
      type: "FeatureCollection",
      features: [],
    };
    for (let x = 0; x < 128; x += 1) {
      let lng = map.current.unproject([x * cellSize + viewportNW.x, -90]).lng;
      graticule.features.push({
        type: "Feature",
        geometry: {
          type: "LineString",
          coordinates: [
            [lng, -90],
            [lng, 90],
          ],
        },
        properties: { value: x },
      });
    }
    for (let y = 0; y < 128; y += 1) {
      let lat = map.current.unproject([-180, y * cellSize + viewportNW.y]).lat;
      graticule.features.push({
        type: "Feature",
        geometry: {
          type: "LineString",
          coordinates: [
            [-180, lat],
            [180, lat],
          ],
        },
        properties: { value: y },
      });
    }

    map.current.addSource("graticule", {
      type: "geojson",
      data: graticule,
    });

    map.current.addLayer({
      id: "graticule",
      type: "line",
      source: "graticule",
    });

    const gridLabelPoints: GeoJSON.FeatureCollection<
      GeoJSON.Geometry,
      GeoJSON.GeoJsonProperties
    > = {
      type: "FeatureCollection",
      features: [],
    };
    for (let x = 0; x < 128; x += 1) {
      for (let y = 0; y < 128; y += 1) {
        let nw = map.current.unproject([
          x * cellSize + viewportNW.x + cellSize / 32,
          y * cellSize + viewportNW.y + cellSize / 32,
        ]);
        gridLabelPoints.features.push({
          type: "Feature",
          geometry: {
            type: "Point",
            coordinates: [nw.lng, nw.lat],
          },
          properties: {
            label: `${x - 57}, ${50 - y}`,
          },
        });
      }
    }
    map.current.addSource("grid-labels-source", {
      type: "geojson",
      data: gridLabelPoints,
    });

    map.current.addLayer({
      id: "grid-labels-layer",
      type: "symbol",
      source: "grid-labels-source",
      layout: {
        "text-field": ["get", "label"],
        "text-font": ["Open Sans Semibold", "Arial Unicode MS Bold"],
        "text-offset": [0, 0],
        "text-anchor": "top-left",
        "text-rotation-alignment": "map",
      },
      paint: {
        "text-halo-width": 1,
        "text-halo-blur": 3,
        "text-halo-color": "rgba(255,255,255,0.8)",
      },
      minzoom: 4,
    });

    const grid: GeoJSON.FeatureCollection<
      GeoJSON.Geometry,
      GeoJSON.GeoJsonProperties
    > = {
      type: "FeatureCollection",
      features: [],
    };
    for (let x = 0; x < 128; x += 1) {
      for (let y = 0; y < 128; y += 1) {
        let nw = map.current.unproject([
          x * cellSize + viewportNW.x,
          y * cellSize + viewportNW.y,
        ]);
        let ne = map.current.unproject([
          x * cellSize + viewportNW.x + cellSize,
          y * cellSize + viewportNW.y,
        ]);
        let se = map.current.unproject([
          x * cellSize + viewportNW.x + cellSize,
          y * cellSize + viewportNW.y + cellSize,
        ]);
        let sw = map.current.unproject([
          x * cellSize + viewportNW.x,
          y * cellSize + viewportNW.y + cellSize,
        ]);
        const editCount = (cellsData as Record<string, number>)[
          `${x - 57},${50 - y}`
        ];
        grid.features.push({
          type: "Feature",
          id: x * 100 + y,
          geometry: {
            type: "Polygon",
            coordinates: [
              [
                [nw.lng, nw.lat],
                [ne.lng, ne.lat],
                [se.lng, se.lat],
                [sw.lng, sw.lat],
                [nw.lng, nw.lat],
              ],
            ],
          },
          properties: {
            x: x,
            y: y,
            cellX: x - 57,
            cellY: 50 - y,
            label: `${x - 57}, ${50 - y}`,
            color: editCount ? colorGradient.getColor(editCount) : "#888888",
            opacity: editCount ? Math.min((editCount / 150) * 0.25, 0.5) : 0,
          },
        });
      }
    }

    map.current.addSource("grid-source", {
      type: "geojson",
      data: grid,
    });

    map.current.addLayer(
      {
        id: "grid-layer",
        type: "fill",
        source: "grid-source",
        paint: {
          "fill-opacity": 0,
        },
      },
      "grid-labels-layer"
    );

    map.current.addLayer(
      {
        id: "heatmap-layer",
        type: "fill",
        source: "grid-source",
        paint: {
          "fill-color": ["get", "color"],
          "fill-opacity": ["get", "opacity"],
          "fill-outline-color": [
            "case",
            ["boolean", ["feature-state", "selected"], false],
            "white",
            "transparent",
          ],
        },
      },
      "grid-labels-layer"
    );
    const fullscreenControl = new mapboxgl.FullscreenControl();
    (fullscreenControl as unknown as { _container: HTMLElement })._container =
      mapWrapper.current;
    map.current.addControl(fullscreenControl);
    map.current.addControl(new mapboxgl.NavigationControl());

    let singleClickTimeout: NodeJS.Timeout | null = null;
    map.current.on("click", "grid-layer", (e) => {
      const features = e.features;
      if (singleClickTimeout) return;
      singleClickTimeout = setTimeout(() => {
        singleClickTimeout = null;
        if (features && features[0]) {
          const cell = {
            x: features[0].properties!.cellX,
            y: features[0].properties!.cellY,
          };
          router.push({ query: { cell: cell.x + "," + cell.y } });
        }
      }, 200);
    });

    map.current.on("dblclick", "grid-layer", (e) => {
      if (singleClickTimeout) clearTimeout(singleClickTimeout);
      singleClickTimeout = null;
    });

    setHeatmapLoaded(true);
  }, [cellsData, mapLoaded, router, setHeatmapLoaded]);

  useEffect(() => {
    if (countsData) {
      const newCounts: Record<number, [number, number, number]> = {};
      for (const line of countsData.split("\n")) {
        const nums = line.split(",").map((count) => parseInt(count, 10));
        newCounts[nums[0]] = [nums[1], nums[2], nums[3]];
      }
      setCounts(newCounts);
    }
  }, [setCounts, countsData]);

  return (
    <>
      <div
        className={`${styles["map-wrapper"]} ${
          sidebarOpen ? styles["map-wrapper-sidebar-open"] : ""
        }`}
        ref={mapWrapper}
      >
        <div ref={mapContainer} className={styles["map-container"]}>
          <Sidebar
            selectedCell={selectedCell}
            clearSelectedCell={() => router.push({ query: {} })}
            setSelectedCells={setSelectedCells}
            map={map}
            counts={counts}
            countsError={countsError}
          />
          <ToggleLayersControl map={map} />
          <SearchBar
            map={map}
            clearSelectedCell={() => router.push({ query: {} })}
            counts={counts}
          />
        </div>
      </div>
    </>
  );
};

export default Map;