"use client";

import { useEffect, useRef, useCallback } from "react";
import maplibregl from "maplibre-gl";
import "maplibre-gl/dist/maplibre-gl.css";

import { getRasterTileTemplateUrl, getVectorTileTemplateUrl } from "@/api/tiles";
import { initDrawing } from "@/lib/drawingEngine";
import { initSelect } from "@/lib/selectingEngine";
import { initPoint } from "@/lib/pointEngine";
import { initPath } from "@/lib/pathEngine";
import { initCircle } from "@/lib/circleEngine";
import { createEditingEngine } from "@/lib/editingEngine";
import { FeatureCollection, Geometry } from "@/lib/useEditorState";
import { BACKGROUND_LAYER_OPTIONS, BackgroundLayerVisibility } from "@/lib/backgroundLayers";

type MapProps = {
    mode: "idle" | "draw" | "select" | "add-point" | "add-path" | "add-circle";
    draft: FeatureCollection;
    backgroundVisibility: BackgroundLayerVisibility;
    selectedEntityId: string | null;
    selectedEntityName: string | null;
    selectedEntityTypeId: string | null;
    onSelectFeatureId: (id: string | number | null) => void;
    onCreateFeature: (feature: FeatureCollection["features"][number]) => void;
    onDeleteFeature: (id: string | number) => void;
    onUpdateFeature: (id: string | number, geometry: Geometry) => void;
};

type PointIconSpec = {
    id: string;
    fill: string;
    stroke: string;
    label: string;
};

const DEFAULT_POINT_ICON_ID = "point-icon-default";
const PATH_ARROW_ICON_ID = "path-arrow-icon";

const POINT_ICON_SPECS: PointIconSpec[] = [
    { id: "point-icon-country", fill: "#1d4ed8", stroke: "#1e3a8a", label: "C" },
    { id: "point-icon-castle", fill: "#7c3aed", stroke: "#4c1d95", label: "F" },
    { id: "point-icon-kingdom", fill: "#ca8a04", stroke: "#854d0e", label: "K" },
    { id: "point-icon-city", fill: "#0f766e", stroke: "#134e4a", label: "T" },
    { id: "point-icon-region", fill: "#b91c1c", stroke: "#7f1d1d", label: "R" },
    { id: "point-icon-event", fill: "#be123c", stroke: "#881337", label: "E" },
    { id: DEFAULT_POINT_ICON_ID, fill: "#475569", stroke: "#1e293b", label: "P" },
];

const POINT_ICON_BY_TYPE: Record<string, string> = {
    country: "point-icon-country",
    castle: "point-icon-castle",
    kingdom: "point-icon-kingdom",
    city: "point-icon-city",
    region: "point-icon-region",
    event: "point-icon-event",
};

export default function Map({
    mode,
    draft,
    backgroundVisibility,
    selectedEntityId,
    selectedEntityName,
    selectedEntityTypeId,
    onSelectFeatureId,
    onCreateFeature,
    onDeleteFeature,
    onUpdateFeature,
}: MapProps) {
    const mapRef = useRef<maplibregl.Map | null>(null);
    const modeRef = useRef<MapProps["mode"]>(mode);
    const draftRef = useRef<FeatureCollection>(draft);
    const backgroundVisibilityRef = useRef<BackgroundLayerVisibility>(backgroundVisibility);
    const selectedEntityIdRef = useRef<string | null>(selectedEntityId);
    const selectedEntityNameRef = useRef<string | null>(selectedEntityName);
    const selectedEntityTypeIdRef = useRef<string | null>(selectedEntityTypeId);
    const onSelectFeatureIdRef = useRef(onSelectFeatureId);
    const onCreateRef = useRef(onCreateFeature);
    const onDeleteRef = useRef(onDeleteFeature);
    const onUpdateRef = useRef(onUpdateFeature);

    const editingEngineRef = useRef<ReturnType<typeof createEditingEngine> | null>(null);

    useEffect(() => {
        modeRef.current = mode;
    }, [mode]);

    useEffect(() => {
        const map = mapRef.current;
        if (!map) return;
        if (mode !== "add-path") {
            (map.getSource("draw-path-preview") as maplibregl.GeoJSONSource | undefined)?.setData({
                type: "FeatureCollection",
                features: [],
            });
        }
        if (mode !== "add-circle") {
            (map.getSource("draw-circle-preview") as maplibregl.GeoJSONSource | undefined)?.setData({
                type: "FeatureCollection",
                features: [],
            });
        }
    }, [mode]);

    useEffect(() => {
        draftRef.current = draft;
    }, [draft]);

    useEffect(() => {
        selectedEntityIdRef.current = selectedEntityId;
    }, [selectedEntityId]);

    useEffect(() => {
        selectedEntityNameRef.current = selectedEntityName;
    }, [selectedEntityName]);

    useEffect(() => {
        selectedEntityTypeIdRef.current = selectedEntityTypeId;
    }, [selectedEntityTypeId]);

    useEffect(() => {
        onSelectFeatureIdRef.current = onSelectFeatureId;
    }, [onSelectFeatureId]);

    useEffect(() => {
        backgroundVisibilityRef.current = backgroundVisibility;
        const map = mapRef.current;
        if (!map || !map.isStyleLoaded()) return;
        applyBackgroundLayerVisibility(map, backgroundVisibility);
    }, [backgroundVisibility]);

    useEffect(() => {
        onCreateRef.current = onCreateFeature;
    }, [onCreateFeature]);

    useEffect(() => {
        onDeleteRef.current = onDeleteFeature;
    }, [onDeleteFeature]);

    useEffect(() => {
        onUpdateRef.current = onUpdateFeature;
    }, [onUpdateFeature]);

    useEffect(() => {
        if (!editingEngineRef.current) {
            editingEngineRef.current = createEditingEngine({
                mapRef,
                onUpdate: (id, geometry) => onUpdateRef.current?.(id, geometry),
            });
        }
    }, []);

    /**
     * Push given draft into map sources (idempotent).
     * Always clear feature-state to avoid stale selection overlays after undo/replace.
     */
    const applyDraftToMap = useCallback((fc: FeatureCollection) => {
        const map = mapRef.current;
        if (!map) return;

        const countriesSource = map.getSource("countries") as maplibregl.GeoJSONSource | undefined;
        const placesSource = map.getSource("places") as maplibregl.GeoJSONSource | undefined;

        if (!countriesSource || !placesSource) return;

        // clear all feature-state (selection) to prevent ghost layers after undo
        map.removeFeatureState({ source: "countries" });

        const { polygons, points } = splitDraftFeatures(fc);

        countriesSource.setData(polygons);
        placesSource.setData(points);
    }, []);

    useEffect(() => {
        const map = new maplibregl.Map({
            container: "map",
            attributionControl: false,
            style: {
                version: 8,
                sources: {
                    rasterBase: {
                        type: "raster",
                        tiles: [getRasterTileTemplateUrl()],
                        tileSize: 256,
                        minzoom: 0,
                        maxzoom: 6,
                    },
                    base: {
                        type: "vector",
                        tiles: [getVectorTileTemplateUrl()],
                        minzoom: 0,
                        maxzoom: 6,
                    },
                },
                layers: [
                    {
                        id: "background",
                        type: "background",
                        paint: {
                            "background-color": "#0b1220",
                        },
                    },
                    {
                        id: "raster-base-layer",
                        type: "raster",
                        source: "rasterBase",
                        paint: {
                            "raster-opacity": 0.92,
                            "raster-resampling": "linear",
                        },
                    },
                    {
                        id: "graticules-line",
                        type: "line",
                        source: "base",
                        "source-layer": "graticules",
                        paint: {
                            "line-color": "#334155",
                            "line-width": [
                                "interpolate",
                                ["linear"],
                                ["zoom"],
                                0, 0.3,
                                4, 0.6,
                                6, 0.8,
                            ],
                            "line-opacity": 0.55,
                        },
                    },
                    {
                        id: "land",
                        type: "fill",
                        source: "base",
                        "source-layer": "land",
                        paint: {
                            "fill-color": "#1e293b",
                            "fill-opacity": 0.25,
                        },
                    },
                    {
                        id: "bg-countries-fill",
                        type: "fill",
                        source: "base",
                        "source-layer": "countries",
                        paint: {
                            "fill-color": "#334155",
                            "fill-opacity": 0.28,
                        },
                    },
                    {
                        id: "bg-country-borders-line",
                        type: "line",
                        source: "base",
                        "source-layer": "country_borders",
                        paint: {
                            "line-color": "#cbd5e1",
                            "line-width": [
                                "interpolate",
                                ["linear"],
                                ["zoom"],
                                0, 0.2,
                                4, 0.5,
                                6, 1.1,
                            ],
                            "line-opacity": 0.85,
                        },
                    },
                    {
                        id: "regions-line",
                        type: "line",
                        source: "base",
                        "source-layer": "regions",
                        paint: {
                            "line-color": "#475569",
                            "line-width": [
                                "interpolate",
                                ["linear"],
                                ["zoom"],
                                0, 0.2,
                                4, 0.6,
                                6, 1,
                            ],
                            "line-opacity": 0.6,
                        },
                    },
                    {
                        id: "lakes-fill",
                        type: "fill",
                        source: "base",
                        "source-layer": "lakes",
                        paint: {
                            "fill-color": "#1d4ed8",
                            "fill-opacity": 0.45,
                        },
                    },
                    {
                        id: "rivers-line",
                        type: "line",
                        source: "base",
                        "source-layer": "rivers",
                        paint: {
                            "line-color": "#38bdf8",
                            "line-width": [
                                "interpolate",
                                ["linear"],
                                ["zoom"],
                                0, 0.25,
                                4, 0.8,
                                6, 1.5,
                            ],
                            "line-opacity": 0.85,
                        },
                    },
                    {
                        id: "geolines-line",
                        type: "line",
                        source: "base",
                        "source-layer": "geolines",
                        paint: {
                            "line-color": "#94a3b8",
                            "line-width": 1.2,
                            "line-opacity": 0.8,
                        },
                    },
                ],
            },
            center: [0, 20],
            zoom: 2,
        });

        mapRef.current = map;

        map.on("load", async () => {
            const placesMinZoom = 5;

            applyBackgroundLayerVisibility(map, backgroundVisibilityRef.current);
            const hasPathArrowIcon = ensurePathArrowIcon(map);

            // preview (drawing)
            map.addSource("draw-preview", {
                type: "geojson",
                data: {
                    type: "FeatureCollection",
                    features: [],
                },
            });

            map.addLayer({
                id: "draw-preview-fill",
                type: "fill",
                source: "draw-preview",
                paint: {
                    "fill-color": "#22c55e",
                    "fill-opacity": 0.4,
                },
            });

            map.addLayer({
                id: "draw-preview-line",
                type: "line",
                source: "draw-preview",
                paint: {
                    "line-color": "#16a34a",
                    "line-width": 2,
                },
            });

            map.addSource("draw-circle-preview", {
                type: "geojson",
                data: {
                    type: "FeatureCollection",
                    features: [],
                },
            });

            map.addLayer({
                id: "draw-circle-preview-fill",
                type: "fill",
                source: "draw-circle-preview",
                paint: {
                    "fill-color": "#0ea5e9",
                    "fill-opacity": 0.25,
                },
            });

            map.addLayer({
                id: "draw-circle-preview-line",
                type: "line",
                source: "draw-circle-preview",
                paint: {
                    "line-color": "#0284c7",
                    "line-width": 2,
                    "line-opacity": 0.95,
                },
            });

            map.addSource("draw-path-preview", {
                type: "geojson",
                data: {
                    type: "FeatureCollection",
                    features: [],
                },
            });

            map.addLayer({
                id: "draw-path-preview-line",
                type: "line",
                source: "draw-path-preview",
                paint: {
                    "line-color": "#38bdf8",
                    "line-width": 3,
                    "line-opacity": 0.9,
                    "line-dasharray": [1.2, 0.9],
                },
            });

            if (hasPathArrowIcon) {
                map.addLayer({
                    id: "draw-path-preview-arrows",
                    type: "symbol",
                    source: "draw-path-preview",
                    layout: {
                        "symbol-placement": "line",
                        "symbol-spacing": 56,
                        "icon-image": PATH_ARROW_ICON_ID,
                        "icon-size": 0.45,
                        "icon-allow-overlap": true,
                        "icon-ignore-placement": true,
                    },
                });
            }

            // data thật
            map.addSource("countries", {
                type: "geojson",
                data: {
                    type: "FeatureCollection",
                    features: [],
                },
                promoteId: "id",

            });

            map.addLayer({
                id: "countries-fill",
                type: "fill",
                source: "countries",
                filter: ["==", ["geometry-type"], "Polygon"],
                paint: {
                    "fill-color": [
                        "case",
                        ["boolean", ["feature-state", "selected"], false],
                        "#22c55e", // selected
                        [
                            "==",
                            ["coalesce", ["get", "entity_id"], ""],
                            "",
                        ],
                        "#ef4444", // no entity
                        "#f59e0b", // linked entity
                    ],
                    "fill-opacity": 0.5,
                },
            });

            map.addLayer({
                id: "countries-line",
                type: "line",
                source: "countries",
                filter: ["==", ["geometry-type"], "Polygon"],
                paint: {
                    "line-color": "#fbbf24",
                    "line-width": 2,
                },
            });

            map.addLayer({
                id: "routes-line",
                type: "line",
                source: "countries",
                filter: ["==", ["geometry-type"], "LineString"],
                paint: {
                    "line-color": [
                        "case",
                        ["boolean", ["feature-state", "selected"], false],
                        "#22c55e",
                        ["==", ["coalesce", ["get", "entity_id"], ""], ""],
                        "#ef4444",
                        "#38bdf8",
                    ],
                    "line-width": [
                        "interpolate",
                        ["linear"],
                        ["zoom"],
                        1, 2.2,
                        4, 3.2,
                        6, 4.2,
                    ],
                    "line-opacity": 0.9,
                },
            });

            if (hasPathArrowIcon) {
                map.addLayer({
                    id: "routes-arrow",
                    type: "symbol",
                    source: "countries",
                    filter: ["==", ["geometry-type"], "LineString"],
                    layout: {
                        "symbol-placement": "line",
                        "symbol-spacing": 60,
                        "icon-image": PATH_ARROW_ICON_ID,
                        "icon-size": 0.5,
                        "icon-allow-overlap": true,
                        "icon-ignore-placement": true,
                    },
                });
            }

            map.addSource("places", {
                type: "geojson",
                data: {
                    type: "FeatureCollection",
                    features: [],
                },
            });

            // editing overlays
            map.addSource("edit-shape", {
                type: "geojson",
                data: { type: "FeatureCollection", features: [] },
            });
            map.addSource("edit-handles", {
                type: "geojson",
                data: { type: "FeatureCollection", features: [] },
            });

            map.addLayer({
                id: "edit-shape-line",
                type: "line",
                source: "edit-shape",
                paint: {
                    "line-color": "#38bdf8",
                    "line-width": 3,
                },
            });

            map.addLayer({
                id: "edit-handles-circle",
                type: "circle",
                source: "edit-handles",
                paint: {
                    "circle-color": "#f97316",
                    "circle-radius": 12,
                    "circle-stroke-color": "#0f172a",
                    "circle-stroke-width": 3,
                },
            });

            // fallback layer so points are still visible even if icon cannot be loaded
            map.addLayer({
                id: "places-circle",
                type: "circle",
                source: "places",
                minzoom: placesMinZoom,
                paint: {
                    "circle-color": [
                        "case",
                        [
                            "==",
                            ["coalesce", ["get", "entity_id"], ""],
                            "",
                        ],
                        "#ef4444",
                        "#10b981",
                    ],
                    "circle-radius": 4,
                    "circle-stroke-color": "#ffffff",
                    "circle-stroke-width": 1,
                    "circle-opacity": 0.85,
                },
            });

            // Add type-specific point icons (country/castle/kingdom/...) and render with symbol layer.
            const hasTypeIcons = ensurePointIcons(map);
            if (hasTypeIcons && !map.getLayer("places-symbol")) {
                map.addLayer({
                    id: "places-symbol",
                    type: "symbol",
                    source: "places",
                    minzoom: placesMinZoom,
                    layout: {
                        "icon-image": buildPointIconExpression(),
                        "icon-size": 0.5,
                        "icon-anchor": "center",
                        "icon-allow-overlap": true,
                    },
                });
            }

            // init drawing
            const cleanup = initDrawing(
                map,
                () => modeRef.current,
                (geometry: Geometry) => {
                    const id = crypto.randomUUID ? crypto.randomUUID() : Date.now();
                    onCreateRef.current({
                        type: "Feature",
                        properties: {
                            id,
                            entity_id: selectedEntityIdRef.current || null,
                            entity_ids: selectedEntityIdRef.current ? [selectedEntityIdRef.current] : [],
                            entity_name: selectedEntityNameRef.current || null,
                            entity_type_id: selectedEntityTypeIdRef.current || null,
                        },
                        geometry,
                    });
                }
            );

            const cleanupSelect = initSelect(
                map,
                () => modeRef.current,
                (id: string | number) => {
                    // ensure edit overlays are cleared when a feature gets removed
                    editingEngineRef.current?.clearEditing();
                    onSelectFeatureIdRef.current?.(null);
                    onDeleteRef.current(id);
                },
                (feature) => editingEngineRef.current?.beginEditing(feature),
                (id) => onSelectFeatureIdRef.current?.(id)
            );

            const cleanupPoint = initPoint(
                map,
                () => modeRef.current,
                (geometry: Geometry) => {
                    const id = crypto.randomUUID ? crypto.randomUUID() : Date.now();
                    onCreateRef.current({
                        type: "Feature",
                        properties: {
                            id,
                            entity_id: selectedEntityIdRef.current || null,
                            entity_ids: selectedEntityIdRef.current ? [selectedEntityIdRef.current] : [],
                            entity_name: selectedEntityNameRef.current || null,
                            entity_type_id: selectedEntityTypeIdRef.current || null,
                        },
                        geometry,
                    });
                }
            );

            const cleanupPath = initPath(
                map,
                () => modeRef.current,
                (geometry: Geometry) => {
                    const id = crypto.randomUUID ? crypto.randomUUID() : Date.now();
                    onCreateRef.current({
                        type: "Feature",
                        properties: {
                            id,
                            entity_id: selectedEntityIdRef.current || null,
                            entity_ids: selectedEntityIdRef.current ? [selectedEntityIdRef.current] : [],
                            entity_name: selectedEntityNameRef.current || null,
                            entity_type_id: selectedEntityTypeIdRef.current || null,
                        },
                        geometry,
                    });
                }
            );

            const cleanupCircle = initCircle(
                map,
                () => modeRef.current,
                (geometry: Geometry) => {
                    const id = crypto.randomUUID ? crypto.randomUUID() : Date.now();
                    onCreateRef.current({
                        type: "Feature",
                        properties: {
                            id,
                            entity_id: selectedEntityIdRef.current || null,
                            entity_ids: selectedEntityIdRef.current ? [selectedEntityIdRef.current] : [],
                            entity_name: selectedEntityNameRef.current || null,
                            entity_type_id: selectedEntityTypeIdRef.current || null,
                        },
                        geometry,
                    });
                }
            );

            map.on("remove", cleanupCircle);
            map.on("remove", cleanupPath);
            map.on("remove", cleanupPoint);

            map.on("remove", cleanupSelect);

            map.on("remove", cleanup);

            // after everything mounted, push current draft to sources
            applyDraftToMap(draftRef.current);

            editingEngineRef.current?.bindEditEvents(map);
        });

        return () => map.remove();
    }, [applyDraftToMap]);

    // sync draft -> map sources and drop edit overlays if feature vanished
    useEffect(() => {
        applyDraftToMap(draft);
        const editingId = editingEngineRef.current?.editingRef.current?.id;
        if (editingId !== undefined && editingId !== null) {
            const stillExists = draft.features.some((f) => f.properties.id === editingId);
            if (!stillExists) {
                editingEngineRef.current?.clearEditing();
            }
        }
    }, [draft, applyDraftToMap]);

    return <div id="map" style={{ width: "100%", height: "100vh" }} />;
}

function applyBackgroundLayerVisibility(
    map: maplibregl.Map,
    visibility: BackgroundLayerVisibility
) {
    for (const layer of BACKGROUND_LAYER_OPTIONS) {
        if (!map.getLayer(layer.id)) continue;
        map.setLayoutProperty(
            layer.id,
            "visibility",
            visibility[layer.id] ? "visible" : "none"
        );
    }
}

function splitDraftFeatures(fc: FeatureCollection) {
    const polygons = {
        type: "FeatureCollection",
        features: fc.features.filter((f) => f.geometry.type !== "Point"),
    } as FeatureCollection;

    const points = {
        type: "FeatureCollection",
        features: fc.features.filter((f) => f.geometry.type === "Point"),
    } as FeatureCollection;

    return { polygons, points };
}

function ensurePathArrowIcon(map: maplibregl.Map): boolean {
    if (map.hasImage(PATH_ARROW_ICON_ID)) return true;
    const imageData = createPathArrowImageData();
    if (!imageData) return false;
    map.addImage(PATH_ARROW_ICON_ID, imageData, { pixelRatio: 2 });
    return true;
}

function createPathArrowImageData(): ImageData | null {
    const size = 56;
    const canvas = document.createElement("canvas");
    canvas.width = size;
    canvas.height = size;
    const ctx = canvas.getContext("2d");
    if (!ctx) return null;

    ctx.clearRect(0, 0, size, size);

    ctx.strokeStyle = "#0f172a";
    ctx.fillStyle = "#38bdf8";
    ctx.lineWidth = 4;
    ctx.lineJoin = "round";
    ctx.lineCap = "round";

    ctx.beginPath();
    ctx.moveTo(8, 16);
    ctx.lineTo(28, 16);
    ctx.lineTo(28, 10);
    ctx.lineTo(46, 28);
    ctx.lineTo(28, 46);
    ctx.lineTo(28, 40);
    ctx.lineTo(8, 40);
    ctx.closePath();
    ctx.fill();
    ctx.stroke();

    return ctx.getImageData(0, 0, size, size);
}

function ensurePointIcons(map: maplibregl.Map): boolean {
    let added = false;
    for (const spec of POINT_ICON_SPECS) {
        if (map.hasImage(spec.id)) {
            added = true;
            continue;
        }

        const imageData = createPointIconImageData(spec);
        if (!imageData) continue;
        map.addImage(spec.id, imageData, { pixelRatio: 2 });
        added = true;
    }
    return added;
}

function createPointIconImageData(spec: PointIconSpec): ImageData | null {
    const size = 64;
    const radius = 18;
    const canvas = document.createElement("canvas");
    canvas.width = size;
    canvas.height = size;
    const ctx = canvas.getContext("2d");
    if (!ctx) return null;

    ctx.clearRect(0, 0, size, size);

    // soft shadow
    ctx.fillStyle = "rgba(2, 6, 23, 0.28)";
    ctx.beginPath();
    ctx.arc(size / 2, size / 2 + 4, radius, 0, Math.PI * 2);
    ctx.fill();

    // icon body
    ctx.fillStyle = spec.fill;
    ctx.strokeStyle = spec.stroke;
    ctx.lineWidth = 4;
    ctx.beginPath();
    ctx.arc(size / 2, size / 2, radius, 0, Math.PI * 2);
    ctx.fill();
    ctx.stroke();

    // short type mark
    ctx.fillStyle = "#ffffff";
    ctx.textAlign = "center";
    ctx.textBaseline = "middle";
    ctx.font = "700 20px sans-serif";
    ctx.fillText(spec.label, size / 2, size / 2 + 0.5);

    return ctx.getImageData(0, 0, size, size);
}

function buildPointIconExpression(): maplibregl.ExpressionSpecification {
    const expression: unknown[] = ["match", ["coalesce", ["get", "entity_type_id"], ""]];

    for (const [typeId, iconId] of Object.entries(POINT_ICON_BY_TYPE)) {
        expression.push(typeId, iconId);
    }

    expression.push(DEFAULT_POINT_ICON_ID);
    return expression as maplibregl.ExpressionSpecification;
}