import * as vscode from "vscode"
import {
    LanguageClient,
    LanguageClientOptions,
    ServerOptions,
    TransportKind
} from "vscode-languageclient/node"
import {
    formatCdlFile,
    completionHandlerCdl,
    hoverCdlHandler,
    formatDefFile,
    isFirstLineMachine,
    diagnosticHandler,
    cdlDocumentSymbolProvider,
    defDocumentSymbolProvider,
    definitionCdlEventHandler
} from "./common/handlers"
import { registerLogger, traceError, traceLog, traceVerbose } from "./common/log/logging"
import {
    checkVersion,
    getInterpreterDetails,
    initializePython,
    onDidChangePythonInterpreter,
    resolveInterpreter
} from "./common/python"
import { disposeServerResources, restartServer } from "./common/server"
import { checkIfConfigurationChanged, getInterpreterFromSetting } from "./common/settings"
import { loadServerDefaults } from "./common/setup"
import { getLSClientTraceLevel } from "./common/utilities"
import { createOutputChannel, onDidChangeConfiguration, registerCommand } from "./common/vscodeapi"
import { registerNxTclDebugger } from "./debugger/register"

let client: LanguageClient | undefined

export async function activate(context: vscode.ExtensionContext) {
    registerNxTclDebugger(context)

    // This is required to get server name and module. This should be
    // the first thing that we do in this extension.
    const serverInfo = loadServerDefaults()
    const serverName = serverInfo.name
    const serverId = serverInfo.module
    const pythonDebugMode = process.env.USE_DEBUGPY?.toLowerCase() === "true"

    // Setup logging
    const outputChannel = createOutputChannel(serverName)
    context.subscriptions.push(outputChannel, registerLogger(outputChannel))

    const changeLogLevel = async (c: vscode.LogLevel, g: vscode.LogLevel) => {
        const level = getLSClientTraceLevel(c, g)
        await client?.setTrace(level)
    }

    context.subscriptions.push(
        outputChannel.onDidChangeLogLevel(async (e) => {
            await changeLogLevel(e, vscode.env.logLevel)
        }),
        vscode.env.onDidChangeLogLevel(async (e) => {
            await changeLogLevel(outputChannel.logLevel, e)
        })
    )

    // Log Server information
    traceLog(`Name: ${serverInfo.name}`)
    traceLog(`Module: ${serverInfo.module}`)
    traceVerbose(`Full Server Info: ${JSON.stringify(serverInfo)}`)

    const runServerImpl = async () => {
        const interpreter = getInterpreterFromSetting(serverId)
        if (interpreter && interpreter.length > 0) {
            if (checkVersion(await resolveInterpreter(interpreter))) {
                traceVerbose(
                    `Using interpreter from ${serverInfo.module}.interpreter: ${interpreter.join(" ")}`
                )
                client = await restartServer(serverId, serverName, outputChannel, client)
            }
            return
        }

        const interpreterDetails = await getInterpreterDetails()
        if (interpreterDetails.path) {
            traceVerbose(
                `Using interpreter from Python extension: ${interpreterDetails.path.join(" ")}`
            )
            client = await restartServer(serverId, serverName, outputChannel, client)
            return
        }

        traceError(
            "Python interpreter missing:\r\n" +
                "[Option 1] Select python interpreter using the ms-python.python.\r\n" +
                `[Option 2] Set an interpreter using "${serverId}.interpreter" setting.\r\n` +
                "Please use Python 3.8 or greater."
        )
    }

    // Serialize server (re)starts. Overlapping triggers (interpreter change,
    // config change, restart command, initial activation) would otherwise each
    // read the stale module-level `client`, start a new server and leave the
    // previous one running orphaned -> hints/hover shown multiple times.
    let runServerQueue: Promise<void> = Promise.resolve()
    const runServer = () => {
        runServerQueue = runServerQueue.catch(() => undefined).then(() => runServerImpl())
        return runServerQueue
    }

    if (!pythonDebugMode) {
        context.subscriptions.push(
            onDidChangePythonInterpreter(async () => {
                await runServer()
            })
        )
    }

    context.subscriptions.push(
        onDidChangeConfiguration(async (e: vscode.ConfigurationChangeEvent) => {
            if (checkIfConfigurationChanged(e, serverId)) {
                await runServer()
            }
        }),
        registerCommand(`${serverId}.restart`, async () => {
            await runServer()
        })
    )

    setImmediate(async () => {
        if (pythonDebugMode) {
            // A debugpy listen session is attached to exactly one process. Do not
            // subscribe to interpreter changes during startup, as the Python
            // extension can emit a duplicate event and restart that process.
            traceLog("Python debug mode: starting one stable server session")
            await runServer()
            return
        }

        const interpreter = getInterpreterFromSetting(serverId)
        if (interpreter === undefined || interpreter.length === 0) {
            traceLog(`Python extension loading`)
            await initializePython(context.subscriptions)
            traceLog(`Python extension loaded`)
        } else {
            await runServer()
        }
    })

    // Folding ranges for TCL are provided by the language server
    // (folding_range_provider in lsp_server.py). No client-side provider here to
    // avoid duplicate folding regions.

    //
    const formatCdlProvider = vscode.languages.registerDocumentFormattingEditProvider(
        { scheme: "file", language: "cdl" },
        {
            provideDocumentFormattingEdits(document: vscode.TextDocument): vscode.TextEdit[] {
                const text = document.getText()
                const formattedText = formatCdlFile(text)
                const fullRange = new vscode.Range(
                    document.positionAt(0),
                    document.positionAt(text.length)
                )
                return [vscode.TextEdit.replace(fullRange, formattedText)]
            }
        }
    )

    context.subscriptions.push(formatCdlProvider)

    const completionCdlProvider = vscode.languages.registerCompletionItemProvider(
        { scheme: "file", language: "cdl" },
        {
            provideCompletionItems(
                document: vscode.TextDocument,
                position: vscode.Position,
                token: vscode.CancellationToken,
                context: vscode.CompletionContext
            ) {
                return completionHandlerCdl(document, position)
            }
        },
        " " // Trigger completion on space
    )
    context.subscriptions.push(completionCdlProvider)

    const hoverCdlProvider = vscode.languages.registerHoverProvider(
        { scheme: "file", language: "cdl" },
        {
            provideHover(
                document: vscode.TextDocument,
                position: vscode.Position,
                token: vscode.CancellationToken
            ) {
                return hoverCdlHandler(document, position)
            }
        }
    )
    context.subscriptions.push(hoverCdlProvider)

    const definitionCdlEventProvider = vscode.languages.registerDefinitionProvider(
        { scheme: "file", language: "cdl" },
        {
            provideDefinition(document, position, token) {
                return definitionCdlEventHandler(document, position, token)
            }
        }
    )
    context.subscriptions.push(definitionCdlEventProvider)

    const formatDefProvider = vscode.languages.registerDocumentFormattingEditProvider(
        { scheme: "file", language: "def" },
        {
            provideDocumentFormattingEdits(document: vscode.TextDocument): vscode.TextEdit[] {
                const text = document.getText()
                const formattedText = formatDefFile(text)
                const fullRange = new vscode.Range(
                    document.positionAt(0),
                    document.positionAt(text.length)
                )
                return [vscode.TextEdit.replace(fullRange, formattedText)]
            }
        }
    )

    context.subscriptions.push(formatDefProvider)

    const cdlSymbolProvider = vscode.languages.registerDocumentSymbolProvider(
        { scheme: "file", language: "cdl" },
        {
            provideDocumentSymbols(document: vscode.TextDocument) {
                return cdlDocumentSymbolProvider(document)
            }
        }
    )
    context.subscriptions.push(cdlSymbolProvider)

    // Outline now provided by the language server (Document Symbols). Removing TS provider.
    const defSymbolProvider = vscode.languages.registerDocumentSymbolProvider(
        { scheme: "file", language: "def" },
        {
            provideDocumentSymbols(document: vscode.TextDocument) {
                return defDocumentSymbolProvider(document)
            }
        }
    )
    context.subscriptions.push(defSymbolProvider)

    // Diagnostics collection
    const diagnosticCollectionCdl = vscode.languages.createDiagnosticCollection("cdl")
    const diagnosticCollectionDef = vscode.languages.createDiagnosticCollection("def")
    context.subscriptions.push(diagnosticCollectionCdl, diagnosticCollectionDef)

    const diagnosticTimers = new Map<string, ReturnType<typeof setTimeout>>()
    const updateDiagnostics = (document: vscode.TextDocument) => {
        if (document.languageId === "cdl") {
            diagnosticCollectionCdl.set(document.uri, diagnosticHandler(document))
        } else if (document.languageId === "def") {
            diagnosticCollectionDef.set(document.uri, diagnosticHandler(document))
        }
    }
    const scheduleDiagnostics = (document: vscode.TextDocument) => {
        const key = document.uri.toString()
        const previous = diagnosticTimers.get(key)
        if (previous !== undefined) {
            clearTimeout(previous)
        }
        diagnosticTimers.set(
            key,
            setTimeout(() => {
                diagnosticTimers.delete(key)
                updateDiagnostics(document)
            }, 120)
        )
    }

    // Check if the first line of the CDL file contains "MACHINE"
    context.subscriptions.push(
        vscode.workspace.onDidOpenTextDocument((document) => {
            if (document.languageId === "cdl" || document.languageId === "def") {
                updateDiagnostics(document)
            }
        }),
        vscode.workspace.onDidChangeTextDocument((event) => {
            const document = event.document
            if (document.languageId === "cdl" || document.languageId === "def") {
                scheduleDiagnostics(document)
            }
        }),
        vscode.workspace.onDidCloseTextDocument((document) => {
            const key = document.uri.toString()
            const timer = diagnosticTimers.get(key)
            if (timer !== undefined) {
                clearTimeout(timer)
                diagnosticTimers.delete(key)
            }
            diagnosticCollectionCdl.delete(document.uri)
            diagnosticCollectionDef.delete(document.uri)
        }),
        {
            dispose() {
                for (const timer of diagnosticTimers.values()) {
                    clearTimeout(timer)
                }
                diagnosticTimers.clear()
            }
        }
    )

    for (const document of vscode.workspace.textDocuments) {
        if (document.languageId === "cdl" || document.languageId === "def") {
            updateDiagnostics(document)
        }
    }
}

export function deactivate(): Thenable<void> | undefined {
    if (!client) {
        disposeServerResources()
        return undefined
    }
    return client.stop().finally(disposeServerResources)
}