// *****************************************************************************
// Copyright (C) 2020 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 { injectable } from '@theia/core/shared/inversify';
import { Position, Range } from '@theia/core/shared/vscode-languageserver-protocol';
import { RecursivePartial } from '@theia/core/lib/common/types';
import * as monaco from '@theia/monaco-editor-core';
import { Selection } from '@theia/editor/lib/browser';

export interface MonacoRangeReplace {
    insert: monaco.IRange;
    replace: monaco.IRange
};
export namespace MonacoRangeReplace {
    export function is(v: Partial<monaco.IRange> | MonacoRangeReplace): v is MonacoRangeReplace {
        return (v as MonacoRangeReplace).insert !== undefined;
    }
}

@injectable()
export class MonacoToProtocolConverter {

    asPosition(lineNumber: undefined | null, column: undefined | null): {};
    asPosition(lineNumber: number, column: undefined | null): Pick<Position, 'line'>;
    asPosition(lineNumber: undefined | null, column: number): Pick<Position, 'character'>;
    asPosition(lineNumber: number, column: number): Position;
    asPosition(lineNumber: number | undefined | null, column: number | undefined | null): Partial<Position>;
    asPosition(lineNumber: number | undefined | null, column: number | undefined | null): Partial<Position> {
        const line = typeof lineNumber !== 'number' ? undefined : lineNumber - 1;
        const character = typeof column !== 'number' ? undefined : column - 1;
        return {
            line, character
        };
    }

    asRange(range: undefined): undefined;
    asRange(range: monaco.IRange): Range;
    asRange(range: monaco.IRange | undefined): Range | undefined;
    asRange(range: monaco.IRange | { insert: monaco.IRange; replace: monaco.IRange }): Range;
    asRange(range: Partial<monaco.IRange>): RecursivePartial<Range>;
    asRange(range: Partial<monaco.IRange> | undefined): RecursivePartial<Range> | undefined;
    asRange(range: Partial<monaco.IRange> | undefined | MonacoRangeReplace): RecursivePartial<Range> | undefined {
        if (range === undefined) {
            return undefined;
        }

        if (MonacoRangeReplace.is(range)) {
            return this.asRange(range.insert);

        } else {
            const start = this.asPosition(range.startLineNumber, range.startColumn);
            const end = this.asPosition(range.endLineNumber, range.endColumn);
            return {
                start, end
            };
        }
    }

    asSelection(selection: monaco.Selection | null): Selection {
        if (!selection) {
            return {
                start: { line: 0, character: 0 },
                end: { line: 0, character: 0 },
                direction: 'ltr'
            };
        }
        const start = this.asPosition(selection.selectionStartLineNumber, selection.selectionStartColumn);
        const end = this.asPosition(selection.positionLineNumber, selection.positionColumn);
        return {
            start,
            end,
            direction: selection.getDirection() === monaco.SelectionDirection.LTR ? 'ltr' : 'rtl'
        };
    }

}