// *****************************************************************************
// Copyright (C) 2023 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.
 *--------------------------------------------------------------------------------------------*/
import { ArrayUtils, CommandService, DisposableCollection, Event, ILogger, nls, QuickInputButton, QuickInputService, QuickPickInput, QuickPickItem, URI, } from '@theia/core';
import { inject, injectable, named } from '@theia/core/shared/inversify';
import { NotebookKernelService, NotebookKernel, NotebookKernelMatchResult, SourceCommand } from './notebook-kernel-service';
import { NotebookModel } from '../view-model/notebook-model';
import { NotebookEditorWidget } from '../notebook-editor-widget';
import { codicon, OpenerService } from '@theia/core/lib/browser';
import { NotebookKernelHistoryService } from './notebook-kernel-history-service';
import { NotebookCommand, NotebookModelResource } from '../../common';
import debounce = require('@theia/core/shared/lodash.debounce');

export const JUPYTER_EXTENSION_ID = 'ms-toolsai.jupyter';

type KernelPick = QuickPickItem & { kernel: NotebookKernel };
function isKernelPick(item: QuickPickInput<QuickPickItem>): item is KernelPick {
    return 'kernel' in item;
}
type GroupedKernelsPick = QuickPickItem & { kernels: NotebookKernel[]; source: string };
function isGroupedKernelsPick(item: QuickPickInput<QuickPickItem>): item is GroupedKernelsPick {
    return 'kernels' in item;
}
type SourcePick = QuickPickItem & { action: SourceCommand };
function isSourcePick(item: QuickPickInput<QuickPickItem>): item is SourcePick {
    return 'action' in item;
}
type InstallExtensionPick = QuickPickItem & { extensionIds: string[] };

type KernelSourceQuickPickItem = QuickPickItem & { command: NotebookCommand; documentation?: string };
function isKernelSourceQuickPickItem(item: QuickPickItem): item is KernelSourceQuickPickItem {
    return 'command' in item;
}

function supportAutoRun(item: QuickPickInput<KernelQuickPickItem>): item is QuickPickItem {
    return 'autoRun' in item && !!item.autoRun;
}

type KernelQuickPickItem = (QuickPickItem & { autoRun?: boolean }) | InstallExtensionPick | KernelPick | GroupedKernelsPick | SourcePick | KernelSourceQuickPickItem;

const KERNEL_PICKER_UPDATE_DEBOUNCE = 200;

export type KernelQuickPickContext =
    { id: string; extension: string } |
    { notebookEditorId: string } |
    { id: string; extension: string; notebookEditorId: string } |
    { ui?: boolean; notebookEditor?: NotebookEditorWidget };

function toKernelQuickPick(kernel: NotebookKernel, selected: NotebookKernel | undefined): KernelPick {
    const res: KernelPick = {
        kernel,
        label: kernel.label,
        description: kernel.description,
        detail: kernel.detail
    };
    if (kernel.id === selected?.id) {
        if (!res.description) {
            res.description = nls.localizeByDefault('Currently Selected');
        } else {
            res.description = nls.localizeByDefault('{0} - Currently Selected', res.description);
        }
    }
    return res;
}

@injectable()
export class NotebookKernelQuickPickService {

    @inject(NotebookKernelService)
    protected readonly notebookKernelService: NotebookKernelService;
    @inject(QuickInputService)
    protected readonly quickInputService: QuickInputService;
    @inject(CommandService)
    protected readonly commandService: CommandService;
    @inject(OpenerService)
    protected readonly openerService: OpenerService;
    @inject(NotebookKernelHistoryService)
    protected readonly notebookKernelHistoryService: NotebookKernelHistoryService;
    @inject(ILogger) @named('notebook')
    protected readonly logger: ILogger;

    async showQuickPick(editor: NotebookModel, wantedId?: string, skipAutoRun?: boolean): Promise<boolean> {
        const notebook = editor;
        const matchResult = this.getMatchingResult(notebook);
        const { selected, all } = matchResult;

        let newKernel: NotebookKernel | undefined;
        if (wantedId) {
            for (const candidate of all) {
                if (candidate.id === wantedId) {
                    newKernel = candidate;
                    break;
                }
            }
            if (!newKernel) {
                console.warn(`wanted kernel DOES NOT EXIST, wanted: ${wantedId}, all: ${all.map(k => k.id)}`);
                return false;
            }
        }

        if (newKernel) {
            this.selectKernel(notebook, newKernel);
            return true;
        }

        const quickPick = this.quickInputService.createQuickPick<KernelQuickPickItem>();
        const quickPickItems = this.getKernelPickerQuickPickItems(matchResult);

        if (quickPickItems.length === 1 && supportAutoRun(quickPickItems[0]) && !skipAutoRun) {
            return this.handleQuickPick(editor, quickPickItems[0], quickPickItems as KernelQuickPickItem[]);
        }

        quickPick.items = quickPickItems;
        quickPick.canSelectMany = false;
        quickPick.placeholder = selected
            ? nls.localizeByDefault("Change kernel for '{0}'", 'current') // TODO get label for current notebook from a label provider
            : nls.localizeByDefault("Select kernel for '{0}'", 'current');

        quickPick.busy = this.notebookKernelService.getKernelDetectionTasks(notebook).length > 0;

        const kernelDetectionTaskListener = this.notebookKernelService.onDidChangeKernelDetectionTasks(() => {
            quickPick.busy = this.notebookKernelService.getKernelDetectionTasks(notebook).length > 0;
        });

        const kernelChangeEventListener = debounce(
            Event.any(
                this.notebookKernelService.onDidChangeSourceActions,
                this.notebookKernelService.onDidAddKernel,
                this.notebookKernelService.onDidRemoveKernel,
                this.notebookKernelService.onDidChangeNotebookAffinity
            ),
            KERNEL_PICKER_UPDATE_DEBOUNCE
        )(async () => {
            // reset quick pick progress
            quickPick.busy = false;

            const currentActiveItems = quickPick.activeItems;
            const newMatchResult = this.getMatchingResult(notebook);
            const newQuickPickItems = this.getKernelPickerQuickPickItems(newMatchResult);
            quickPick.keepScrollPosition = true;

            // recalculate active items
            const activeItems: KernelQuickPickItem[] = [];
            for (const item of currentActiveItems) {
                if (isKernelPick(item)) {
                    const kernelId = item.kernel.id;
                    const sameItem = newQuickPickItems.find(pi => isKernelPick(pi) && pi.kernel.id === kernelId) as KernelPick | undefined;
                    if (sameItem) {
                        activeItems.push(sameItem);
                    }
                } else if (isSourcePick(item)) {
                    const sameItem = newQuickPickItems.find(pi => isSourcePick(pi) && pi.action.command.id === item.action.command.id) as SourcePick | undefined;
                    if (sameItem) {
                        activeItems.push(sameItem);
                    }
                }
            }

            quickPick.items = newQuickPickItems;
            quickPick.activeItems = activeItems;
        }, this);

        const pick = await new Promise<{ selected: KernelQuickPickItem | undefined; items: KernelQuickPickItem[] }>((resolve, reject) => {
            quickPick.onDidAccept(() => {
                const item = quickPick.selectedItems[0];
                if (item) {
                    resolve({ selected: item, items: quickPick.items as KernelQuickPickItem[] });
                } else {
                    resolve({ selected: undefined, items: quickPick.items as KernelQuickPickItem[] });
                }

                quickPick.hide();
            });

            quickPick.onDidHide(() => {
                kernelDetectionTaskListener.dispose();
                kernelChangeEventListener?.dispose();
                quickPick.dispose();
                resolve({ selected: undefined, items: quickPick.items as KernelQuickPickItem[] });
            });
            quickPick.show();
        });

        if (pick.selected) {
            return this.handleQuickPick(editor, pick.selected, pick.items);
        }

        return false;
    }

    protected getKernelPickerQuickPickItems(matchResult: NotebookKernelMatchResult): QuickPickInput<KernelQuickPickItem>[] {
        const quickPickItems: QuickPickInput<KernelQuickPickItem>[] = [];

        if (matchResult.selected) {
            const kernelItem = toKernelQuickPick(matchResult.selected, matchResult.selected);
            quickPickItems.push(kernelItem);
        }

        // TODO use suggested here when kernel affinity is implemented. For now though show all kernels
        matchResult.all.filter(kernel => kernel.id !== matchResult.selected?.id).map(kernel => toKernelQuickPick(kernel, matchResult.selected))
            .forEach(kernel => {
                quickPickItems.push(kernel);
            });

        const shouldAutoRun = quickPickItems.length === 0;

        if (quickPickItems.length > 0) {
            quickPickItems.push({
                type: 'separator'
            });
        }

        // select another kernel quick pick
        quickPickItems.push({
            id: 'selectAnother',
            label: nls.localizeByDefault('Select Another Kernel...'),
            autoRun: shouldAutoRun
        });

        return quickPickItems;
    }

    protected selectKernel(notebook: NotebookModel, kernel: NotebookKernel): void {
        this.logger.debug('Selected notebook kernel', {
            notebook: notebook.uri.toString(),
            kernel: kernel.id
        });
        const currentInfo = this.notebookKernelService.getMatchingKernel(notebook);
        if (currentInfo.selected) {
            // there is already a selected kernel
            this.notebookKernelHistoryService.addMostRecentKernel(currentInfo.selected);
        }
        this.notebookKernelService.selectKernelForNotebook(kernel, notebook);
        this.notebookKernelHistoryService.addMostRecentKernel(kernel);
    }

    protected getMatchingResult(notebook: NotebookModel): NotebookKernelMatchResult {
        const { selected, all } = this.notebookKernelHistoryService.getKernels(notebook);
        const matchingResult = this.notebookKernelService.getMatchingKernel(notebook);
        return {
            selected: selected,
            all: matchingResult.all,
            suggestions: all,
            hidden: []
        };
    }

    protected async handleQuickPick(editor: NotebookModel, pick: KernelQuickPickItem, items: KernelQuickPickItem[]): Promise<boolean> {
        if (pick.id === 'selectAnother') {
            return this.displaySelectAnotherQuickPick(editor, items.length === 1 && items[0] === pick);
        }

        if (isKernelPick(pick)) {
            const newKernel = pick.kernel;
            this.selectKernel(editor, newKernel);
            return true;
        }

        if (isSourcePick(pick)) {
            this.logger.debug('Selected notebook kernel command', {
                notebook: editor.uri.toString(),
                command: pick.action.command.id
            });
            // selected explicitly, it should trigger the execution?
            pick.action.run(this.commandService);
        }

        return true;
    }

    protected async displaySelectAnotherQuickPick(editor: NotebookModel, kernelListEmpty: boolean): Promise<boolean> {
        const notebook: NotebookModel = editor;
        const disposables = new DisposableCollection();
        const quickPick = this.quickInputService.createQuickPick<KernelQuickPickItem>();
        const quickPickItem = await new Promise<KernelQuickPickItem | QuickInputButton | undefined>(resolve => {
            // select from kernel sources
            quickPick.title = kernelListEmpty ? nls.localizeByDefault('Select Kernel') : nls.localizeByDefault('Select Another Kernel');
            quickPick.placeholder = nls.localizeByDefault('Type to choose a kernel source');
            quickPick.busy = true;
            // quickPick.buttons = [this.quickInputService.backButton];
            quickPick.show();

            disposables.push(quickPick.onDidTriggerButton(button => {
                if (button === this.quickInputService.backButton) {
                    resolve(button);
                }
            }));
            quickPick.onDidTriggerItemButton(async e => {

                if (isKernelSourceQuickPickItem(e.item) && e.item.documentation !== undefined) {
                    const uri: URI | undefined = this.isUri(e.item.documentation) ? new URI(e.item.documentation) : await this.commandService.executeCommand(e.item.documentation);
                    if (uri) {
                        (await this.openerService.getOpener(uri, { openExternal: true })).open(uri, { openExternal: true });
                    }
                }
            });
            disposables.push(quickPick.onDidAccept(async () => {
                resolve(quickPick.selectedItems[0]);
            }));
            disposables.push(quickPick.onDidHide(() => {
                resolve(undefined);
            }));

            this.calculateKernelSources(editor).then(quickPickItems => {
                quickPick.items = quickPickItems;
                if (quickPick.items.length > 0) {
                    quickPick.busy = false;
                }
            });

            debounce(
                Event.any(
                    this.notebookKernelService.onDidChangeSourceActions,
                    this.notebookKernelService.onDidAddKernel,
                    this.notebookKernelService.onDidRemoveKernel
                ),
                KERNEL_PICKER_UPDATE_DEBOUNCE,
            )(async () => {
                quickPick.busy = true;
                const quickPickItems = await this.calculateKernelSources(editor);
                quickPick.items = quickPickItems;
                quickPick.busy = false;
            });
        });

        quickPick.hide();
        disposables.dispose();

        if (quickPickItem === this.quickInputService.backButton) {
            return this.showQuickPick(editor, undefined, true);
        }

        if (quickPickItem) {
            const selectedKernelPickItem = quickPickItem as KernelQuickPickItem;
            if (isKernelSourceQuickPickItem(selectedKernelPickItem)) {
                try {
                    const selectedKernelId = await this.executeCommand<string>(notebook, selectedKernelPickItem.command);
                    if (selectedKernelId) {
                        const { all } = this.getMatchingResult(notebook);
                        const notebookKernel = all.find(kernel => kernel.id === `ms-toolsai.jupyter/${selectedKernelId}`);
                        if (notebookKernel) {
                            this.selectKernel(notebook, notebookKernel);
                            return true;
                        }
                        return true;
                    } else {
                        return this.displaySelectAnotherQuickPick(editor, false);
                    }
                } catch (ex) {
                    console.error('Failed to select notebook kernel', ex);
                    return false;
                }
            } else if (isKernelPick(selectedKernelPickItem)) {
                this.selectKernel(notebook, selectedKernelPickItem.kernel);
                return true;
            } else if (isGroupedKernelsPick(selectedKernelPickItem)) {
                await this.selectOneKernel(notebook, selectedKernelPickItem.source, selectedKernelPickItem.kernels);
                return true;
            } else if (isSourcePick(selectedKernelPickItem)) {
                // selected explicitly, it should trigger the execution?
                try {
                    await selectedKernelPickItem.action.run(this.commandService);
                    return true;
                } catch (ex) {
                    console.error('Failed to select notebook kernel', ex);
                    return false;
                }
            }
            // } else if (isSearchMarketplacePick(selectedKernelPickItem)) {
            //     await this.showKernelExtension(
            //         this.paneCompositePartService,
            //         this.extensionWorkbenchService,
            //         this.extensionService,
            //         editor.textModel.viewType,
            //         []
            //     );
            //     return true;
            // } else if (isInstallExtensionPick(selectedKernelPickItem)) {
            //     await this.showKernelExtension(
            //         this.paneCompositePartService,
            //         this.extensionWorkbenchService,
            //         this.extensionService,
            //         editor.textModel.viewType,
            //         selectedKernelPickItem.extensionIds,
            //     );
            //     return true;
            // }
        }

        return false;
    }

    protected isUri(value: string): boolean {
        return /^(?<scheme>\w[\w\d+.-]*):/.test(value);
    }

    protected async calculateKernelSources(editor: NotebookModel): Promise<QuickPickInput<KernelQuickPickItem>[]> {
        const notebook: NotebookModel = editor;

        const actions = await this.notebookKernelService.getKernelSourceActionsFromProviders(notebook);
        const matchResult = this.getMatchingResult(notebook);

        const others = matchResult.all.filter(item => item.extensionId !== JUPYTER_EXTENSION_ID);
        const quickPickItems: QuickPickInput<KernelQuickPickItem>[] = [];

        // group controllers by extension
        for (const group of ArrayUtils.groupBy(others, (a, b) => a.extensionId === b.extensionId ? 0 : 1)) {
            const source = group[0].extensionId;
            if (group.length > 1) {
                quickPickItems.push({
                    label: source,
                    kernels: group
                });
            } else {
                quickPickItems.push({
                    label: group[0].label,
                    kernel: group[0]
                });
            }
        }

        const validActions = actions.filter(action => action.command);

        quickPickItems.push(...validActions.map(action => {
            const buttons = action.documentation ? [{
                iconClass: codicon('info'),
                tooltip: nls.localizeByDefault('Learn More'),
            }] : [];
            return {
                id: typeof action.command! === 'string' ? action.command! : action.command!.id,
                label: action.label,
                description: action.description,
                command: action.command,
                documentation: action.documentation,
                buttons
            };
        }));

        return quickPickItems;
    }

    protected async selectOneKernel(notebook: NotebookModel, source: string, kernels: NotebookKernel[]): Promise<void> {
        const quickPickItems: QuickPickInput<KernelPick>[] = kernels.map(kernel => toKernelQuickPick(kernel, undefined));
        const quickPick = this.quickInputService.createQuickPick<KernelQuickPickItem>();
        quickPick.items = quickPickItems;
        quickPick.canSelectMany = false;

        quickPick.title = nls.localizeByDefault('Select Kernel from {0}', source);

        quickPick.onDidAccept(async () => {
            if (quickPick.selectedItems && quickPick.selectedItems.length > 0 && isKernelPick(quickPick.selectedItems[0])) {
                this.selectKernel(notebook, quickPick.selectedItems[0].kernel);
            }

            quickPick.hide();
            quickPick.dispose();
        });

        quickPick.onDidHide(() => {
            quickPick.dispose();
        });

        quickPick.show();
    }

    protected async executeCommand<T>(notebook: NotebookModel, command: NotebookCommand): Promise<T | undefined | void> {
        const args = (command.arguments || []).concat([NotebookModelResource.create(notebook.uri)]);
        return this.commandService.executeCommand(command.id, ...args);
    }
}