import anser from "anser";
import * as lc from "vscode-languageclient/node";
import * as vscode from "vscode";
import * as ra from "../src/lsp_ext";
import * as Is from "vscode-languageclient/lib/common/utils/is";
import { assert } from "./util";
import * as diagnostics from "./diagnostics";
import { WorkspaceEdit } from "vscode";
import { type Config, prepareVSCodeConfig } from "./config";
import { sep as pathSeparator } from "path";
import { RaLanguageClient } from "./lang_client";

export async function createClient(
    traceOutputChannel: vscode.OutputChannel,
    outputChannel: vscode.OutputChannel,
    initializationOptions: lc.LanguageClientOptions["initializationOptions"],
    serverOptions: lc.ServerOptions,
    config: Config,
    unlinkedFiles: vscode.Uri[],
): Promise<lc.LanguageClient> {
    const raMiddleware: lc.Middleware = {
        workspace: {
            // HACK: This is a workaround, when the client has been disposed, VSCode
            // continues to emit events to the client and the default one for this event
            // attempt to restart the client for no reason
            async didChangeWatchedFile(event, next) {
                if (client.isRunning()) {
                    await next(event);
                }
            },
            async configuration(
                params: lc.ConfigurationParams,
                _token: vscode.CancellationToken,
                _next: lc.ConfigurationRequest.HandlerSignature,
            ) {
                // The rust-analyzer LSP only ever asks for the "rust-analyzer"
                // section, so we only need to support that. Instead of letting
                // the vscode-languageclient handle it, use the `cfg` property
                // in the config.
                if (
                    params.items.length !== 1 ||
                    params.items[0]?.section !== "rust-analyzer" ||
                    params.items[0]?.scopeUri !== undefined
                ) {
                    return new lc.ResponseError(
                        lc.ErrorCodes.InvalidParams,
                        'Only the "rust-analyzer" config section is supported.',
                    );
                }
                return [prepareVSCodeConfig(config.cfg)];
            },
        },
        async handleDiagnostics(
            uri: vscode.Uri,
            diagnosticList: vscode.Diagnostic[],
            next: lc.HandleDiagnosticsSignature,
        ) {
            const preview = config.previewRustcOutput;
            const errorCode = config.useRustcErrorCode;
            diagnosticList.forEach((diag, idx) => {
                const value =
                    typeof diag.code === "string" || typeof diag.code === "number"
                        ? diag.code
                        : diag.code?.value;
                if (
                    // FIXME: We currently emit this diagnostic way too early, before we have
                    // loaded the project fully
                    // value === "unlinked-file" &&
                    value === "temporary-disabled" &&
                    !unlinkedFiles.includes(uri) &&
                    (diag.message === "file not included in crate hierarchy" ||
                        diag.message.startsWith("This file is not included in any crates"))
                ) {
                    const config = vscode.workspace.getConfiguration("rust-analyzer");
                    if (config.get("showUnlinkedFileNotification")) {
                        unlinkedFiles.push(uri);
                        const folder = vscode.workspace.getWorkspaceFolder(uri)?.uri.fsPath;
                        if (folder) {
                            const parentBackslash = uri.fsPath.lastIndexOf(pathSeparator + "src");
                            const parent = uri.fsPath.substring(0, parentBackslash);

                            if (parent.startsWith(folder)) {
                                const path = vscode.Uri.file(parent + pathSeparator + "Cargo.toml");
                                void vscode.workspace.fs.stat(path).then(async () => {
                                    const choice = await vscode.window.showInformationMessage(
                                        `This rust file does not belong to a loaded cargo project. It looks like it might belong to the workspace at ${path.path}, do you want to add it to the linked Projects?`,
                                        "Yes",
                                        "No",
                                        "Don't show this again",
                                    );
                                    switch (choice) {
                                        case undefined:
                                            break;
                                        case "No":
                                            break;
                                        case "Yes": {
                                            const pathToInsert =
                                                "." +
                                                parent.substring(folder.length) +
                                                pathSeparator +
                                                "Cargo.toml";
                                            const value = config
                                                // eslint-disable-next-line @typescript-eslint/no-explicit-any
                                                .get<any[]>("linkedProjects")
                                                ?.concat(pathToInsert);
                                            await config.update("linkedProjects", value, false);
                                            break;
                                        }
                                        case "Don't show this again":
                                            await config.update(
                                                "showUnlinkedFileNotification",
                                                false,
                                                false,
                                            );
                                            break;
                                    }
                                });
                            }
                        }
                    }
                }

                // Abuse the fact that VSCode leaks the LSP diagnostics data field through the
                // Diagnostic class, if they ever break this we are out of luck and have to go
                // back to the worst diagnostics experience ever:)

                // We encode the rendered output of a rustc diagnostic in the rendered field of
                // the data payload of the lsp diagnostic. If that field exists, overwrite the
                // diagnostic code such that clicking it opens the diagnostic in a readonly
                // text editor for easy inspection
                const rendered = (diag as unknown as { data?: { rendered?: string } }).data
                    ?.rendered;
                if (rendered) {
                    if (preview) {
                        const decolorized = anser.ansiToText(rendered);
                        const index = decolorized.match(/^(note|help):/m)?.index || rendered.length;
                        diag.message = decolorized
                            .substring(0, index)
                            .replace(/^ -->[^\n]+\n/m, "");
                    }
                    diag.code = {
                        target: vscode.Uri.from({
                            scheme: diagnostics.URI_SCHEME,
                            path: `/diagnostic message [${idx.toString()}]`,
                            fragment: uri.toString(),
                            query: idx.toString(),
                        }),
                        value: errorCode && value ? value : "Click for full compiler diagnostic",
                    };
                }
            });
            return next(uri, diagnosticList);
        },
        async provideHover(
            document: vscode.TextDocument,
            position: vscode.Position,
            token: vscode.CancellationToken,
            _next: lc.ProvideHoverSignature,
        ) {
            const editor = vscode.window.activeTextEditor;
            const positionOrRange = editor?.selection?.contains(position)
                ? client.code2ProtocolConverter.asRange(editor.selection)
                : client.code2ProtocolConverter.asPosition(position);
            const params = {
                textDocument: client.code2ProtocolConverter.asTextDocumentIdentifier(document),
                position: positionOrRange,
            };
            return client.sendRequest(ra.hover, params, token).then(
                (result) => {
                    if (!result) return null;
                    const hover = client.protocol2CodeConverter.asHover(result);
                    if (result.actions) {
                        hover.contents.push(renderHoverActions(result.actions));
                    }
                    return hover;
                },
                (error) => {
                    client.handleFailedRequest(lc.HoverRequest.type, token, error, null);
                    return Promise.resolve(null);
                },
            );
        },
        // Using custom handling of CodeActions to support action groups and snippet edits.
        // Note that this means we have to re-implement lazy edit resolving ourselves as well.
        async provideCodeActions(
            document: vscode.TextDocument,
            range: vscode.Range,
            context: vscode.CodeActionContext,
            token: vscode.CancellationToken,
            _next: lc.ProvideCodeActionsSignature,
        ) {
            const params: lc.CodeActionParams = {
                textDocument: client.code2ProtocolConverter.asTextDocumentIdentifier(document),
                range: client.code2ProtocolConverter.asRange(range),
                context: await client.code2ProtocolConverter.asCodeActionContext(context, token),
            };
            const callback = async (
                values: (lc.Command | lc.CodeAction | object)[] | null,
            ): Promise<(vscode.Command | vscode.CodeAction)[] | undefined> => {
                if (values === null) return undefined;
                const result: (vscode.CodeAction | vscode.Command)[] = [];
                const groups = new Map<
                    string,
                    {
                        primary: vscode.CodeAction;
                        items: { label: string; arguments: lc.CodeAction }[];
                    }
                >();
                for (const item of values) {
                    // In our case we expect to get code edits only from diagnostics
                    if (lc.CodeAction.is(item)) {
                        assert(!item.command, "We don't expect to receive commands in CodeActions");
                        const action = await client.protocol2CodeConverter.asCodeAction(
                            item,
                            token,
                        );
                        result.push(action);
                        continue;
                    }
                    assertIsCodeActionWithoutEditsAndCommands(item);
                    const kind = client.protocol2CodeConverter.asCodeActionKind(item.kind);
                    const group = item.group;

                    const mkAction = () => {
                        const action = new vscode.CodeAction(item.title, kind);
                        action.command = {
                            command: "rust-analyzer.resolveCodeAction",
                            title: item.title,
                            arguments: [item],
                        };
                        // Set a dummy edit, so that VS Code doesn't try to resolve this.
                        action.edit = new WorkspaceEdit();
                        return action;
                    };

                    if (group) {
                        let entry = groups.get(group);
                        if (!entry) {
                            entry = { primary: mkAction(), items: [] };
                            groups.set(group, entry);
                        } else {
                            entry.items.push({
                                label: item.title,
                                arguments: item,
                            });
                        }
                    } else {
                        result.push(mkAction());
                    }
                }
                for (const [group, { items, primary }] of groups) {
                    // This group contains more than one item, so rewrite it to be a group action
                    if (items.length !== 0) {
                        const args = [
                            {
                                label: primary.title,
                                arguments: primary.command!.arguments![0],
                            },
                            ...items,
                        ];
                        primary.title = group;
                        primary.command = {
                            command: "rust-analyzer.applyActionGroup",
                            title: "",
                            arguments: [args],
                        };
                    }
                    result.push(primary);
                }
                return result;
            };
            return client
                .sendRequest(lc.CodeActionRequest.type, params, token)
                .then(callback, (_error) => undefined);
        },
    };
    const clientOptions: lc.LanguageClientOptions = {
        documentSelector: [{ scheme: "file", language: "rust" }],
        initializationOptions,
        diagnosticCollectionName: "rustc",
        traceOutputChannel,
        outputChannel,
        middleware: raMiddleware,
        markdown: {
            supportHtml: true,
        },
    };

    const client = new RaLanguageClient(
        "rust-analyzer",
        "Rust Analyzer Language Server",
        serverOptions,
        clientOptions,
    );

    // To turn on all proposed features use: client.registerProposedFeatures();
    client.registerFeature(new ExperimentalFeatures(config));
    client.registerFeature(new OverrideFeatures());

    return client;
}

class ExperimentalFeatures implements lc.StaticFeature {
    private readonly testExplorer: boolean;

    constructor(config: Config) {
        this.testExplorer = config.testExplorer || false;
    }

    getState(): lc.FeatureState {
        return { kind: "static" };
    }

    fillClientCapabilities(capabilities: lc.ClientCapabilities): void {
        capabilities.experimental = {
            snippetTextEdit: true,
            codeActionGroup: true,
            hoverActions: true,
            serverStatusNotification: true,
            colorDiagnosticOutput: true,
            openServerLogs: true,
            localDocs: true,
            testExplorer: this.testExplorer,
            commands: {
                commands: [
                    "rust-analyzer.runSingle",
                    "rust-analyzer.debugSingle",
                    "rust-analyzer.showReferences",
                    "rust-analyzer.gotoLocation",
                    "rust-analyzer.triggerParameterHints",
                    "rust-analyzer.rename",
                ],
            },
            ...capabilities.experimental,
        };
    }

    initialize(
        _capabilities: lc.ServerCapabilities,
        _documentSelector: lc.DocumentSelector | undefined,
    ): void {}

    dispose(): void {}

    clear(): void {}
}

class OverrideFeatures implements lc.StaticFeature {
    getState(): lc.FeatureState {
        return { kind: "static" };
    }

    fillClientCapabilities(capabilities: lc.ClientCapabilities): void {
        // Force disable `augmentsSyntaxTokens`, VSCode's textmate grammar is somewhat incomplete
        // making the experience generally worse
        const caps = capabilities.textDocument?.semanticTokens;
        if (caps) {
            caps.augmentsSyntaxTokens = false;
        }
    }

    initialize(
        _capabilities: lc.ServerCapabilities,
        _documentSelector: lc.DocumentSelector | undefined,
    ): void {}

    dispose(): void {}

    clear(): void {}
}

function assertIsCodeActionWithoutEditsAndCommands(
    // eslint-disable-next-line @typescript-eslint/no-explicit-any
    candidate: any,
): asserts candidate is lc.CodeAction & {
    group?: string;
} {
    assert(
        candidate &&
            Is.string(candidate.title) &&
            (candidate.diagnostics === undefined ||
                Is.typedArray(candidate.diagnostics, lc.Diagnostic.is)) &&
            (candidate.group === undefined || Is.string(candidate.group)) &&
            (candidate.kind === undefined || Is.string(candidate.kind)) &&
            candidate.edit === undefined &&
            candidate.command === undefined,
        `Expected a CodeAction without edits or commands, got: ${JSON.stringify(candidate)}`,
    );
}

// Command URIs have a form of command:command-name?arguments, where
// arguments is a percent-encoded array of data we want to pass along to
// the command function. For "Show References" this is a list of all file
// URIs with locations of every reference, and it can get quite long.
// So long in fact that it will fail rendering inside an `a` tag so we need
// to proxy around that. We store the last hover's reference command link
// here, as only one hover can be active at a time, and we don't need to
// keep a history of these.
export let HOVER_REFERENCE_COMMAND: ra.CommandLink[] = [];

function renderCommand(cmd: ra.CommandLink): string {
    HOVER_REFERENCE_COMMAND.push(cmd);
    return `[${cmd.title}](command:rust-analyzer.hoverRefCommandProxy?${
        HOVER_REFERENCE_COMMAND.length - 1
    } '${cmd.tooltip}')`;
}

function renderHoverActions(actions: ra.CommandLinkGroup[]): vscode.MarkdownString {
    // clean up the previous hover ref command
    HOVER_REFERENCE_COMMAND = [];
    const text = actions
        .map(
            (group) =>
                (group.title ? group.title + " " : "") +
                group.commands.map(renderCommand).join(" | "),
        )
        .join(" | ");

    const result = new vscode.MarkdownString(text);
    result.isTrusted = true;
    return result;
}
