// *****************************************************************************
// 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
// *****************************************************************************

/*---------------------------------------------------------------------------------------------
 *  Copyright (c) Microsoft Corporation. All rights reserved.
 *  Licensed under the MIT License. See License.txt in the project root for license information.
 *--------------------------------------------------------------------------------------------*/
// Based on https://github.com/theia-ide/vscode/blob/standalone/0.19.x/src/vs/workbench/contrib/debug/common/debugModel.ts

import * as React from '@theia/core/shared/react';
import { DISABLED_CLASS } from '@theia/core/lib/browser';
import { EditorWidget, Range, Position, EditorOpenerOptions } from '@theia/editor/lib/browser';
import { DebugProtocol } from '@vscode/debugprotocol/lib/debugProtocol';
import { TreeElement } from '@theia/core/lib/browser/source-tree';
import { DebugScope } from '../console/debug-console-items';
import { DebugSource } from './debug-source';
import { RecursivePartial } from '@theia/core';
import { DebugSession } from '../debug-session';
import { DebugThread } from './debug-thread';
import * as monaco from '@theia/monaco-editor-core';
import { stringHash } from '@theia/core/lib/common/hash';

export class DebugStackFrameData {
    readonly raw: DebugProtocol.StackFrame;
}

export class DebugStackFrame extends DebugStackFrameData implements TreeElement {

    constructor(
        readonly thread: DebugThread,
        readonly session: DebugSession,
        readonly id: string
    ) {
        super();
    }

    /**
     * Returns the frame identifier from the debug protocol.
     */
    get frameId(): number {
        return this.raw.id;
    }

    protected _source: DebugSource | undefined;
    get source(): DebugSource | undefined {
        return this._source;
    }
    update(data: Partial<DebugStackFrameData>): void {
        Object.assign(this, data);
        this._source = this.raw.source && this.session.getSource(this.raw.source);
    }

    async restart(): Promise<void> {
        await this.session.sendRequest('restartFrame', this.toArgs({
            threadId: this.thread.id
        }));
    }

    async open(options?: EditorOpenerOptions): Promise<EditorWidget | undefined> {
        if (!this.source) {
            return undefined;
        }
        const { line, column, endLine, endColumn } = this.raw;
        const selection: RecursivePartial<Range> = {
            start: Position.create(this.clampPositive(line - 1), this.clampPositive(column - 1))
        };
        if (typeof endLine === 'number') {
            selection.end = {
                line: this.clampPositive(endLine - 1),
                character: typeof endColumn === 'number' ? this.clampPositive(endColumn - 1) : undefined
            };
        }
        this.source.open({
            mode: 'reveal',
            ...options,
            selection
        });
    }

    /**
     * Debugger can send `column: 0` value despite of initializing the debug session with `columnsStartAt1: true`.
     * This method can be used to ensure that neither `column` nor `column` are negative numbers.
     * See https://github.com/microsoft/vscode-mock-debug/issues/85.
     */
    protected clampPositive(value: number): number {
        return Math.max(value, 0);
    }

    protected scopes: Promise<DebugScope[]> | undefined;
    getScopes(): Promise<DebugScope[]> {
        return this.scopes || (this.scopes = this.doGetScopes());
    }
    protected async doGetScopes(): Promise<DebugScope[]> {
        let response;
        try {
            response = await this.session.sendRequest('scopes', this.toArgs());
        } catch {
            // no-op: ignore debug adapter errors
        }
        if (!response) {
            return [];
        }
        const scopeIds = new Set<number>();
        return response.body.scopes.map(raw => {
            // just as in VS Code, the id is based on the name and location to retain expansion state across multiple pauses
            let id = 0;
            do {
                id = stringHash(`${raw.name}:${raw.line}:${raw.column}`, id);
            } while (scopeIds.has(id));
            scopeIds.add(id);
            return new DebugScope(raw, () => this.session, id);
        });
    }

    // https://github.com/theia-ide/vscode/blob/standalone/0.19.x/src/vs/workbench/contrib/debug/common/debugModel.ts#L324-L335
    async getMostSpecificScopes(range: monaco.IRange): Promise<DebugScope[]> {
        const scopes = await this.getScopes();
        const nonExpensiveScopes = scopes.filter(s => !s.expensive);
        const haveRangeInfo = nonExpensiveScopes.some(s => !!s.range);
        if (!haveRangeInfo) {
            return nonExpensiveScopes;
        }

        const scopesContainingRange = nonExpensiveScopes.filter(scope => scope.range && monaco.Range.containsRange(scope.range, range))
            .sort((first, second) => (first.range!.endLineNumber - first.range!.startLineNumber) - (second.range!.endLineNumber - second.range!.startLineNumber));
        return scopesContainingRange.length ? scopesContainingRange : nonExpensiveScopes;
    }

    protected toArgs<T extends object>(arg?: T): { frameId: number } & T {
        return Object.assign({}, arg, {
            frameId: this.raw.id
        });
    }

    render(): React.ReactNode {
        const classNames = ['theia-debug-stack-frame'];
        if (this.raw.presentationHint === 'label') {
            classNames.push('label');
        }
        if (this.raw.presentationHint === 'subtle') {
            classNames.push('subtle');
        }
        if (!this.source || this.source.raw.presentationHint === 'deemphasize') {
            classNames.push(DISABLED_CLASS);
        }
        return <div className={classNames.join(' ')}>
            <span className='expression' title={this.raw.name}>{this.raw.name}</span>
            {this.renderFile()}
        </div>;
    }
    protected renderFile(): React.ReactNode {
        const { source } = this;
        if (!source) {
            return undefined;
        }
        const origin = source.raw.origin && `\n${source.raw.origin}` || '';
        return <span className='file' title={source.longName + origin}>
            <span className='name'>{source.name}</span>
            <span className='line'>{this.raw.line}:{this.raw.column}</span>
        </span>;
    }

    get range(): monaco.IRange | undefined {
        const { source, line: startLine, column: startColumn, endLine, endColumn } = this.raw;
        if (source) {
            return new monaco.Range(startLine, startColumn, endLine || startLine, endColumn || startColumn);
        }
        return undefined;
    }

}