// *****************************************************************************
// Copyright (C) 2017 TypeFox and others.
//
// This program and the accompanying materials are made available under the
// terms of the Eclipse Public License v. 2.0 which is available at
// http://www.eclipse.org/legal/epl-2.0.
//
// This Source Code may also be made available under the following Secondary
// Licenses when the conditions for such availability set forth in the Eclipse
// Public License v. 2.0 are satisfied: GNU General Public License, version 2
// with the GNU Classpath Exception which is available at
// https://www.gnu.org/software/classpath/license.html.
//
// SPDX-License-Identifier: EPL-2.0 OR GPL-2.0-only WITH Classpath-exception-2.0
// *****************************************************************************

import { ProblemMarker } from '../../common/problem-marker';
import { ProblemManager } from './problem-manager';
import { ProblemCompositeTreeNode } from './problem-composite-tree-node';
import { MarkerNode, MarkerTree, MarkerOptions, MarkerInfoNode, MarkerRootNode } from '../marker-tree';
import { MarkerTreeModel } from '../marker-tree-model';
import { injectable, inject } from '@theia/core/shared/inversify';
import { OpenerOptions, TreeNode } from '@theia/core/lib/browser';
import { Marker } from '../../common/marker';
import { Diagnostic } from '@theia/core/shared/vscode-languageserver-protocol';
import { ProblemUtils } from './problem-utils';
import debounce = require('@theia/core/shared/lodash.debounce');

@injectable()
export class ProblemTree extends MarkerTree<Diagnostic> {

    protected queuedMarkers = new Map<string, ProblemCompositeTreeNode.Child>();

    constructor(
        @inject(ProblemManager) markerManager: ProblemManager,
        @inject(MarkerOptions) markerOptions: MarkerOptions
    ) {
        super(markerManager, markerOptions);
    }

    protected override getMarkerNodes(parent: MarkerInfoNode, markers: Marker<Diagnostic>[]): MarkerNode[] {
        const nodes = super.getMarkerNodes(parent, markers);
        return nodes.sort((a, b) => this.sortMarkers(a, b));
    }

    /**
     * Sort markers based on the following rules:
     * - Markers are fist sorted by `severity`.
     * - Markers are sorted by `line number` if applicable.
     * - Markers are sorted by `column number` if applicable.
     * - Markers are then finally sorted by `owner` if applicable.
     * @param a the first marker for comparison.
     * @param b the second marker for comparison.
     */
    protected sortMarkers(a: MarkerNode, b: MarkerNode): number {
        const markerA = a.marker as Marker<Diagnostic>;
        const markerB = b.marker as Marker<Diagnostic>;

        // Determine the marker with the highest severity.
        const severity = ProblemUtils.severityCompareMarker(markerA, markerB);
        if (severity !== 0) {
            return severity;
        }
        // Determine the marker with the lower line number.
        const lineNumber = ProblemUtils.lineNumberCompare(markerA, markerB);
        if (lineNumber !== 0) {
            return lineNumber;
        }
        // Determine the marker with the lower column number.
        const columnNumber = ProblemUtils.columnNumberCompare(markerA, markerB);
        if (columnNumber !== 0) {
            return columnNumber;
        }
        // Sort by owner in alphabetical order.
        const owner = ProblemUtils.ownerCompare(markerA, markerB);
        if (owner !== 0) {
            return owner;
        }
        return 0;
    }

    protected override insertNodeWithMarkers(node: MarkerInfoNode, markers: Marker<Diagnostic>[]): void {
        // Add the element to the queue.
        // In case a diagnostics collection for the same file already exists, it will be replaced.
        this.queuedMarkers.set(node.id, { node, markers });
        this.doInsertNodesWithMarkers();
    }

    protected doInsertNodesWithMarkers = debounce(() => {
        const root = this.root;
        // Sanity check; This should always be of type `MarkerRootNode`
        if (!MarkerRootNode.is(root)) {
            return;
        }
        const queuedItems = Array.from(this.queuedMarkers.values());
        ProblemCompositeTreeNode.addChildren(root, queuedItems);

        for (const { node, markers } of queuedItems) {
            const children = this.getMarkerNodes(node, markers);
            node.numberOfMarkers = markers.length;
            this.setChildren(node, children);
        }

        this.queuedMarkers.clear();
    }, 50);
}

@injectable()
export class ProblemTreeModel extends MarkerTreeModel {

    @inject(ProblemManager) protected readonly problemManager: ProblemManager;

    protected override getOpenerOptionsByMarker(node: MarkerNode): OpenerOptions | undefined {
        if (ProblemMarker.is(node.marker)) {
            return {
                selection: node.marker.data.range
            };
        }
        return undefined;
    }

    removeNode(node: TreeNode): void {
        if (MarkerInfoNode.is(node)) {
            this.problemManager.cleanAllMarkers(node.uri);
        }
        if (MarkerNode.is(node)) {
            const { uri } = node;
            const { owner } = node.marker;
            const diagnostics = this.problemManager.findMarkers({ uri, owner, dataFilter: data => node.marker.data !== data }).map(({ data }) => data);
            this.problemManager.setMarkers(uri, owner, diagnostics);
        }
    }
}