// *****************************************************************************
// Copyright (C) 2018 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 {
    EditorDecoration,
    EditorDecorationOptions,
    OverviewRulerLane,
    EditorDecorator,
    TextEditor,
    MinimapPosition
} from '@theia/editor/lib/browser';
import { DirtyDiff, LineRange, Change } from './diff-computer';
import { URI } from '@theia/core';

export enum DirtyDiffDecorationType {
    AddedLine = 'dirty-diff-added-line',
    RemovedLine = 'dirty-diff-removed-line',
    ModifiedLine = 'dirty-diff-modified-line',
}

const AddedLineDecoration = <EditorDecorationOptions>{
    linesDecorationsClassName: 'dirty-diff-glyph dirty-diff-added-line',
    overviewRuler: {
        color: {
            id: 'editorOverviewRuler.addedForeground'
        },
        position: OverviewRulerLane.Left,
    },
    minimap: {
        color: {
            id: 'minimapGutter.addedBackground'
        },
        position: MinimapPosition.Gutter
    },
    isWholeLine: true
};

const RemovedLineDecoration = <EditorDecorationOptions>{
    linesDecorationsClassName: 'dirty-diff-glyph dirty-diff-removed-line',
    overviewRuler: {
        color: {
            id: 'editorOverviewRuler.deletedForeground'
        },
        position: OverviewRulerLane.Left,
    },
    minimap: {
        color: {
            id: 'minimapGutter.deletedBackground'
        },
        position: MinimapPosition.Gutter
    },
    isWholeLine: false
};

const ModifiedLineDecoration = <EditorDecorationOptions>{
    linesDecorationsClassName: 'dirty-diff-glyph dirty-diff-modified-line',
    overviewRuler: {
        color: {
            id: 'editorOverviewRuler.modifiedForeground'
        },
        position: OverviewRulerLane.Left,
    },
    minimap: {
        color: {
            id: 'minimapGutter.modifiedBackground'
        },
        position: MinimapPosition.Gutter
    },
    isWholeLine: true
};

function getEditorDecorationOptions(change: Change): EditorDecorationOptions {
    if (Change.isAddition(change)) {
        return AddedLineDecoration;
    }
    if (Change.isRemoval(change)) {
        return RemovedLineDecoration;
    }
    return ModifiedLineDecoration;
}

export interface DirtyDiffUpdate extends DirtyDiff {
    readonly editor: TextEditor;
    readonly previousRevisionUri?: URI;
}

@injectable()
export class DirtyDiffDecorator extends EditorDecorator {

    applyDecorations(update: DirtyDiffUpdate): void {
        const decorations = update.changes.map(change => this.toDeltaDecoration(change));
        this.setDecorations(update.editor, decorations);
    }

    protected toDeltaDecoration(change: Change): EditorDecoration {
        const range = LineRange.toRange(change.currentRange);
        const options = getEditorDecorationOptions(change);
        return { range, options };
    }
}