import {
    geoExtent, geoLineIntersection, geoMetersToLat, geoMetersToLon,
    geoSphericalDistance, geoVecInterp, geoHasSelfIntersections,
    geoSphericalClosestNode
} from '../geo';

import { actionAddMidpoint, actionChangeTags, actionMergeNodes } from '../actions';
import { t } from '../util/locale';
import { utilDisplayLabel } from '../util';
import { validationIssue, validationIssueFix } from '../core/validator';


/**
 * Look for roads that can be connected to other roads with a short extension
 */
export function validationAlmostJunction() {
    var type = 'almost_junction';


    function isHighway(entity) {
        return entity.type === 'way' &&
            entity.tags.highway &&
            entity.tags.highway !== 'no' &&
            entity.tags.highway !== 'proposed';
    }

    function isNoexit(node) {
        return node.tags.noexit && node.tags.noexit === 'yes';
    }


    var validation = function checkAlmostJunction(entity, context) {
        if (!isHighway(entity)) return [];
        if (entity.isDegenerate()) return [];

        var graph = context.graph();
        var tree = context.history().tree();
        var issues = [];

        var extendableNodeInfos = findConnectableEndNodesByExtension(entity);
        extendableNodeInfos.forEach(function(extendableNodeInfo) {
            var node = extendableNodeInfo.node;
            var edgeHighway = graph.entity(extendableNodeInfo.wid);

            var fixes = [new validationIssueFix({
                icon: 'iD-icon-abutment',
                title: t('issues.fix.connect_features.title'),
                onClick: function() {
                    var endNode = this.issue.entities[1];
                    var targetEdge = this.issue.data.edge;
                    var crossLoc = this.issue.data.cross_loc;
                    var edgeNodes = [context.graph().entity(targetEdge[0]), context.graph().entity(targetEdge[1])];
                    var closestNodeInfo = geoSphericalClosestNode(edgeNodes, crossLoc);

                    var annotation = t('issues.fix.connect_almost_junction.annotation');
                    // already a point nearby, just connect to that
                    if (closestNodeInfo.distance < 0.75) {
                        context.perform(
                            actionMergeNodes([closestNodeInfo.node.id, endNode.id], closestNodeInfo.node.loc),
                            annotation
                        );
                    // else add the end node to the edge way
                    } else {
                        context.perform(
                            actionAddMidpoint({loc: crossLoc, edge: targetEdge}, endNode),
                            annotation
                        );
                    }
                }
            })];

            if (Object.keys(node.tags).length === 0) {
                // node has no tags, suggest noexit fix
                fixes.push(new validationIssueFix({
                    icon: 'maki-barrier',
                    title: t('issues.fix.tag_as_disconnected.title'),
                    onClick: function() {
                        var nodeID = this.issue.entities[1].id;
                        context.perform(
                            actionChangeTags(nodeID, { noexit: 'yes' }),
                            t('issues.fix.tag_as_disconnected.annotation')
                        );
                    }
                }));
            }

            issues.push(new validationIssue({
                type: type,
                severity: 'warning',
                message: t('issues.almost_junction.message', {
                    feature: utilDisplayLabel(entity, context),
                    feature2: utilDisplayLabel(edgeHighway, context)
                }),
                reference: showReference,
                entities: [entity, node, edgeHighway],
                loc: extendableNodeInfo.node.loc,
                data: {
                    edge: extendableNodeInfo.edge,
                    cross_loc: extendableNodeInfo.cross_loc
                },
                fixes: fixes
            }));
        });

        return issues;


        function showReference(selection) {
            selection.selectAll('.issue-reference')
                .data([0])
                .enter()
                .append('div')
                .attr('class', 'issue-reference')
                .text(t('issues.almost_junction.highway-highway.reference'));
        }


        function isExtendableCandidate(node, way) {
            // can not accurately test vertices on tiles not downloaded from osm - #5938
            var osm = context.connection();
            if (osm && !osm.isDataLoaded(node.loc)) {
                return false;
            }
            if (isNoexit(node) || graph.parentWays(node).length !== 1) {
                return false;
            }

            var occurences = 0;
            for (var index in way.nodes) {
                if (way.nodes[index] === node.id) {
                    occurences += 1;
                    if (occurences > 1) {
                        return false;
                    }
                }
            }
            return true;
        }


        function findConnectableEndNodesByExtension(way) {
            var results = [];
            if (way.isClosed()) return results;

            var testNodes;
            var indices = [0, way.nodes.length - 1];
            indices.forEach(function(nodeIndex) {
                var nodeID = way.nodes[nodeIndex];
                var node = graph.entity(nodeID);

                if (!isExtendableCandidate(node, way)) return;

                var connectionInfo = canConnectByExtend(way, nodeIndex);
                if (!connectionInfo) return;

                testNodes = graph.childNodes(way).slice();   // shallow copy
                testNodes[nodeIndex] = testNodes[nodeIndex].move(connectionInfo.cross_loc);

                // don't flag issue if connecting the ways would cause self-intersection
                if (geoHasSelfIntersections(testNodes, nodeID)) return;

                results.push(connectionInfo);
            });

            return results;
        }


        function canConnectByExtend(way, endNodeIdx) {
            var EXTEND_TH_METERS = 5;
            var tipNid = way.nodes[endNodeIdx];  // the 'tip' node for extension point
            var midNid = endNodeIdx === 0 ? way.nodes[1] : way.nodes[way.nodes.length - 2];  // the other node of the edge
            var tipNode = graph.entity(tipNid);
            var midNode = graph.entity(midNid);
            var lon = tipNode.loc[0];
            var lat = tipNode.loc[1];
            var lon_range = geoMetersToLon(EXTEND_TH_METERS, lat) / 2;
            var lat_range = geoMetersToLat(EXTEND_TH_METERS) / 2;
            var queryExtent = geoExtent([
                [lon - lon_range, lat - lat_range],
                [lon + lon_range, lat + lat_range]
            ]);

            // first, extend the edge of [midNode -> tipNode] by EXTEND_TH_METERS and find the "extended tip" location
            var edgeLen = geoSphericalDistance(midNode.loc, tipNode.loc);
            var t = EXTEND_TH_METERS / edgeLen + 1.0;
            var extTipLoc = geoVecInterp(midNode.loc, tipNode.loc, t);

            // then, check if the extension part [tipNode.loc -> extTipLoc] intersects any other ways
            var intersected = tree.intersects(queryExtent, graph);
            for (var i = 0; i < intersected.length; i++) {
                if (!isHighway(intersected[i]) || intersected[i].id === way.id) continue;

                var way2 = intersected[i];
                for (var j = 0; j < way2.nodes.length - 1; j++) {
                    var nA = graph.entity(way2.nodes[j]);
                    var nB = graph.entity(way2.nodes[j + 1]);
                    var crossLoc = geoLineIntersection([tipNode.loc, extTipLoc], [nA.loc, nB.loc]);
                    if (crossLoc) {
                        return {
                            node: tipNode,
                            wid: way2.id,
                            edge: [nA.id, nB.id],
                            cross_loc: crossLoc
                        };
                    }
                }
            }
            return null;
        }
    };

    validation.type = type;

    return validation;
}