import * as vscode from "vscode";
import * as lc from "vscode-languageclient/node";
import * as ra from "./lsp_ext";

import { Config, substituteVariablesInEnv, substituteVSCodeVariables } from "./config";
import { createClient } from "./client";
import { isRustEditor, log, RustEditor } from "./util";
import { ServerStatusParams } from "./lsp_ext";
import { PersistentState } from "./persistent_state";
import { bootstrap } from "./bootstrap";

export type Workspace =
    | {
          kind: "Workspace Folder";
      }
    | {
          kind: "Detached Files";
          files: vscode.TextDocument[];
      };

export type CommandFactory = {
    enabled: (ctx: Ctx) => Cmd;
    disabled?: (ctx: Ctx) => Cmd;
};

export class Ctx {
    readonly statusBar: vscode.StatusBarItem;
    readonly config: Config;

    private client: lc.LanguageClient | undefined;
    private _serverPath: string | undefined;
    private traceOutputChannel: vscode.OutputChannel | undefined;
    private outputChannel: vscode.OutputChannel | undefined;
    private clientSubscriptions: Disposable[];
    private state: PersistentState;
    private commandFactories: Record<string, CommandFactory>;
    private commandDisposables: Disposable[];

    workspace: Workspace;

    constructor(
        readonly extCtx: vscode.ExtensionContext,
        workspace: Workspace,
        commandFactories: Record<string, CommandFactory>
    ) {
        extCtx.subscriptions.push(this);
        this.statusBar = vscode.window.createStatusBarItem(vscode.StatusBarAlignment.Left);
        this.statusBar.text = "rust-analyzer";
        this.statusBar.tooltip = "ready";
        this.statusBar.command = "rust-analyzer.analyzerStatus";
        this.statusBar.show();
        this.workspace = workspace;
        this.clientSubscriptions = [];
        this.commandDisposables = [];
        this.commandFactories = commandFactories;

        this.state = new PersistentState(extCtx.globalState);
        this.config = new Config(extCtx);

        this.updateCommands();
    }

    dispose() {
        this.config.dispose();
        this.statusBar.dispose();
        void this.disposeClient();
        this.commandDisposables.forEach((disposable) => disposable.dispose());
    }

    clientFetcher() {
        const self = this;
        return {
            get client(): lc.LanguageClient | undefined {
                return self.client;
            },
        };
    }

    async getClient() {
        if (!this.traceOutputChannel) {
            this.traceOutputChannel = vscode.window.createOutputChannel(
                "Rust Analyzer Language Server Trace"
            );
            this.pushExtCleanup(this.traceOutputChannel);
        }
        if (!this.outputChannel) {
            this.outputChannel = vscode.window.createOutputChannel("Rust Analyzer Language Server");
            this.pushExtCleanup(this.outputChannel);
        }

        if (!this.client) {
            this._serverPath = await bootstrap(this.extCtx, this.config, this.state).catch(
                (err) => {
                    let message = "bootstrap error. ";

                    message +=
                        'See the logs in "OUTPUT > Rust Analyzer Client" (should open automatically). ';
                    message +=
                        'To enable verbose logs use { "rust-analyzer.trace.extension": true }';

                    log.error("Bootstrap error", err);
                    throw new Error(message);
                }
            );
            const newEnv = substituteVariablesInEnv(
                Object.assign({}, process.env, this.config.serverExtraEnv)
            );
            const run: lc.Executable = {
                command: this._serverPath,
                options: { env: newEnv },
            };
            const serverOptions = {
                run,
                debug: run,
            };

            let rawInitializationOptions = vscode.workspace.getConfiguration("rust-analyzer");

            if (this.workspace.kind === "Detached Files") {
                rawInitializationOptions = {
                    detachedFiles: this.workspace.files.map((file) => file.uri.fsPath),
                    ...rawInitializationOptions,
                };
            }

            const initializationOptions = substituteVSCodeVariables(rawInitializationOptions);

            this.client = await createClient(
                this.traceOutputChannel,
                this.outputChannel,
                initializationOptions,
                serverOptions
            );
            this.pushClientCleanup(
                this.client.onNotification(ra.serverStatus, (params) =>
                    this.setServerStatus(params)
                )
            );
        }
        return this.client;
    }

    async activate() {
        log.info("Activating language client");
        const client = await this.getClient();
        await client.start();
        this.updateCommands();
        return client;
    }

    async deactivate() {
        log.info("Deactivating language client");
        await this.client?.stop();
        this.updateCommands();
    }

    async stop() {
        log.info("Stopping language client");
        await this.disposeClient();
        this.updateCommands();
    }

    private async disposeClient() {
        this.clientSubscriptions?.forEach((disposable) => disposable.dispose());
        this.clientSubscriptions = [];
        await this.client?.dispose();
        this._serverPath = undefined;
        this.client = undefined;
    }

    get activeRustEditor(): RustEditor | undefined {
        const editor = vscode.window.activeTextEditor;
        return editor && isRustEditor(editor) ? editor : undefined;
    }

    get extensionPath(): string {
        return this.extCtx.extensionPath;
    }

    get subscriptions(): Disposable[] {
        return this.extCtx.subscriptions;
    }

    get serverPath(): string | undefined {
        return this._serverPath;
    }

    private updateCommands() {
        this.commandDisposables.forEach((disposable) => disposable.dispose());
        this.commandDisposables = [];
        const fetchFactory = (factory: CommandFactory, fullName: string) => {
            return this.client && this.client.isRunning()
                ? factory.enabled
                : factory.disabled ||
                      ((_) => () =>
                          vscode.window.showErrorMessage(
                              `command ${fullName} failed: rust-analyzer server is not running`
                          ));
        };
        for (const [name, factory] of Object.entries(this.commandFactories)) {
            const fullName = `rust-analyzer.${name}`;
            const callback = fetchFactory(factory, fullName)(this);
            this.commandDisposables.push(vscode.commands.registerCommand(fullName, callback));
        }
    }

    setServerStatus(status: ServerStatusParams) {
        let icon = "";
        const statusBar = this.statusBar;
        switch (status.health) {
            case "ok":
                statusBar.tooltip = status.message ?? "Ready";
                statusBar.command = undefined;
                statusBar.color = undefined;
                statusBar.backgroundColor = undefined;
                break;
            case "warning":
                statusBar.tooltip =
                    (status.message ? status.message + "\n" : "") + "Click to reload.";

                statusBar.command = "rust-analyzer.reloadWorkspace";
                statusBar.color = new vscode.ThemeColor("statusBarItem.warningForeground");
                statusBar.backgroundColor = new vscode.ThemeColor(
                    "statusBarItem.warningBackground"
                );
                icon = "$(warning) ";
                break;
            case "error":
                statusBar.tooltip =
                    (status.message ? status.message + "\n" : "") + "Click to reload.";

                statusBar.command = "rust-analyzer.reloadWorkspace";
                statusBar.color = new vscode.ThemeColor("statusBarItem.errorForeground");
                statusBar.backgroundColor = new vscode.ThemeColor("statusBarItem.errorBackground");
                icon = "$(error) ";
                break;
        }
        if (!status.quiescent) icon = "$(sync~spin) ";
        statusBar.text = `${icon}rust-analyzer`;
    }

    pushExtCleanup(d: Disposable) {
        this.extCtx.subscriptions.push(d);
    }

    private pushClientCleanup(d: Disposable) {
        this.clientSubscriptions.push(d);
    }
}

export interface Disposable {
    dispose(): void;
}
export type Cmd = (...args: any[]) => unknown;