import fs from 'fs';
import * as process from 'process';
import { getDiagnostics } from './parser';

export function log(str: string) {
  fs.appendFileSync('/home/sylv/latex-lsp/test', str + "\n");
}

export function error(str: string) {
  log("ERROR:" + str);
  process.exit(1);
}

let init = false;

type RPCResult = {
  jsonrpc: string,
  id: string,
} & ({
  result: any,
} | {
  error: any,
})

type RPCRequest = {
  id: string;
  jsonrpc: string,
  method: string,
  params: string,
}

type InitRequest = RPCRequest & {
  method: 'initialize',
}

// ASSUMES that is has the right format
function sendRPC(obj: any) {
  const msg = JSON.stringify(obj);
  const buff = Buffer.from(msg, 'utf-8');
  
  const fullmessage = `Content-Length: ${buff.byteLength}\r\n\r\n${msg}`;

  log("Sending message: " + fullmessage.replace(/\n/g, '\\n').replace(/\r/g, '\\r'))

  process.stdout.cork()
  process.stdout.write(fullmessage);
  process.stdout.uncork();
}

function sendRPCMessage(req: RPCRequest, result: any = undefined, error: any = undefined) {
  if (!result && !error) {
    error("Invalid rpc message to send")
    return;
  }

  sendRPC({
    id: req.id,
    jsonrpc: req.jsonrpc,
    result,
    error
  } as RPCResult)
}

function notifyRPC(method: string, params: any) {
  sendRPC({
    jsonrpc: '2.0',
    method,
    params,
  })
}

type TextDocumentDidOpen = RPCRequest & {
  method: 'textDocument/didOpen',
  params: {
    textDocument: {
      uri: string;
      languageId: string;
      version: number;
      text: string;
    }
  }
}

type TextDocumentCodeAction = RPCRequest & {
  method: 'textDocument/codeAction',
  params: {
    range: Range,
    textDocument: {
      uri: string,
    }
  },
};

type Position = {
  line: number,
  character: number
}

type Range = {
  start: Position,
  end: Position,
}

export type Dialog = {
  range: Range,
  message: string,
  severity: Severity,
}

export enum Severity {
  Error = 1,
  Warning = 2,
  Information = 3,
  Hint = 4,
}

const saveRes: Record<string, (Dialog & {replacements: string[]})[]> = {  };

async function handleJSON(req: RPCRequest) {
  log(`New Message entered: method: ${req.method}`);

  if (init) {
    if (req.method === 'initialized') {
      // On init confirm do nothing
      return;
    } else if (req.method === 'textDocument/didOpen') {
      const reqO: TextDocumentDidOpen = req as any;

      if (reqO.params.textDocument.languageId !== 'latex') {
        error(`This server only supports latex! Got: ${reqO.params.textDocument.languageId}`)
        return;
      }

      const diags = await getDiagnostics(reqO.params.textDocument.text);

      saveRes[reqO.params.textDocument.uri] = diags;
      
      const params = {
        uri: reqO.params.textDocument.uri,
        diagnostics: diags.map(a => ({
          message: a.message,
          range: a.range,
          severity: a.severity,
        }) as Dialog),
      }

      notifyRPC('textDocument/publishDiagnostics', params);

      //error(`TODO ${req.method}`);
    } else if (req.method === 'textDocument/codeAction') {
      const reqO: TextDocumentCodeAction = req as any;

      const diagRecord = saveRes[reqO.params.textDocument.uri];

      if (!diagRecord) {
        sendRPCMessage(req, [{
          title: "No diagnostics found in this file"
        }]);
        return;
      }

      log(JSON.stringify(req.params));
    
      error("TODO handle " + req.method);
    } else {
      error(`Handle: ${req.method} after init`);
    }
  } else {
    if (req.method === 'initialize') {
      log("Recived init");

      init = true;

      log(JSON.stringify(req));

      sendRPCMessage(req, {
        capabilities: {
          diagnosticProvider: {
            // TODO change in the future when the server also checks the ib file as well
            interFileDependencies: false,
            workspaceDiagnostics: false,
          },
          codeActionProvider: {
            codeActionKinds: [ "quickfix" ]
          }
        },
        serverInfo: {
          name: "Super Cool latex server",
          version: "1.0.0",
        }
      });

      return;
    } else {
      error(`Expected init method found '${req.method}'`)
    }
  }
}


export function handleData(data: Buffer) {
  let strData = data.toString();
  let jsonData = strData.split('\n');

  let req: RPCRequest;

  if (jsonData.length === 3) {
    try {
      req = JSON.parse(jsonData[2]);
    } catch (e) {
      log("Failed to parse json 1/2! Msg:\n");
      log(strData.replace(/\n/g, '\\n').replace(/\r/g, '\\r'));
      log("\n\nFailed to parse json 2/2! JSON Line:\n");
      log(jsonData[2]);
      return;
    }
    handleJSON(req);
    return;
  }

  for (let i = 2; i < jsonData.length; i += 2) {

    let jsonLine = jsonData[i];
    if (i != jsonData.length - 1) {
      let index = jsonLine.indexOf('Content-Length');
      if (index == -1) {
        error("Handling multiline expected 'Content-Length'");
        return;
      }

      try {
        req = JSON.parse(jsonLine.substring(0, index));
      } catch (e) {
        log("Failed to parse json 1/2! Msg:\n");
        log(strData.replace(/\n/g, '\\n').replace(/\r/g, '\\r'));
        log("\n\nFailed to parse json 2/2! JSON Line:\n");
        log(jsonLine.substring(0, index));
        return;
      }
    } else {
      try {
        req = JSON.parse(jsonLine);
      } catch (e) {
        log("Failed to parse json 1/2! Msg:\n");
        log(strData.replace(/\n/g, '\\n').replace(/\r/g, '\\r'));
        log("\n\nFailed to parse json 2/2! JSON Line:\n");
        log(jsonLine);
        return;
      }

    }

    handleJSON(req);
  }
}