/*
** 2023-08-29
**
** The author disclaims copyright to this source code.  In place of
** a legal notice, here is a blessing:
**
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains the main application entry pointer for the
** JS implementation of the SQLTester framework.
*/

// UNDER CONSTRUCTION. Still being ported from the Java impl.

import sqlite3ApiInit from '/jswasm/sqlite3.mjs';

const sqlite3 = await sqlite3ApiInit();

const log = (...args)=>{
  console.log('SQLTester:',...args);
};

// Return a new enum entry value
const newE = ()=>Object.create(null);

const newObj = (props)=>Object.assign(newE(), props);

/**
   Modes for how to escape (or not) column values and names from
   SQLTester.execSql() to the result buffer output.
*/
const ResultBufferMode = Object.assign(Object.create(null),{
  //! Do not append to result buffer
  NONE: newE(),
  //! Append output escaped.
  ESCAPED: newE(),
  //! Append output as-is
  ASIS: newE()
});

/**
   Modes to specify how to emit multi-row output from
   SQLTester.execSql() to the result buffer.
*/
const ResultRowMode = newObj({
  //! Keep all result rows on one line, space-separated.
  ONLINE: newE(),
  //! Add a newline between each result row.
  NEWLINE: newE()
});

class SQLTesterException extends globalThis.Error {
  constructor(...args){
    super(args.join(''));
  }
  isFatal() { return false; }
}

SQLTesterException.toss = (...args)=>{
  throw new SQLTesterException(...args);
}

class DbException extends SQLTesterException {
  constructor(pDb, rc, closeDb){
    super("DB error #"+rc+": "+sqlite3.capi.sqlite3_errmsg(pDb));
    if( closeDb ) sqlite3.capi.sqlite3_close_v2(pDb);
  }
  isFatal() { return true; }
}

class TestScriptFailed extends SQLTesterException {
  constructor(testScript, ...args){
    super(testScript.getPutputPrefix(),': ',...args);
  }
  isFatal() { return true; }
}

class UnknownCommand extends SQLTesterException {
  constructor(...args){
    super(...args);
  }
}

class IncompatibleDirective extends SQLTesterException {
  constructor(...args){
    super(...args);
  }
}

const toss = (errType, ...args)=>{
  if( !(errType instanceof SQLTesterException)){
    args.unshift(errType);
    errType = SQLTesterException;
  }
  throw new errType(...args);
};

const __utf8Decoder = new TextDecoder();
const __utf8Encoder = new TextEncoder('utf-8');
const __SAB = ('undefined'===typeof globalThis.SharedArrayBuffer)
      ? function(){} : globalThis.SharedArrayBuffer;

const Util = newObj({
  toss,

  unlink: function(fn){
    return 0==sqlite3.wasm.sqlite3_wasm_vfs_unlink(0,fn);
  },

  argvToString: (list)=>list.join(" "),

  utf8Decode: function(arrayBuffer, begin, end){
    return __utf8Decoder.decode(
      (arrayBuffer.buffer instanceof __SAB)
        ? arrayBuffer.slice(begin, end)
        : arrayBuffer.subarray(begin, end)
    );
  },

  utf8Encode: (str)=>__utf8Encoder.encode(str)
})/*Util*/;

class Outer {
  #lnBuf = [];
  #verbosity = 0;
  #logger = console.log.bind(console);

  constructor(){
  }

  out(...args){
    if(!this.#lnBuf.length && this.getOutputPrefix ){
      this.#lnBuf.push(this.getOutputPrefix());
    }
    this.#lnBuf.push(...args);
    return this;
  }
  outln(...args){
    if(!this.#lnBuf.length && this.getOutputPrefix ){
      this.#lnBuf.push(this.getOutputPrefix());
    }
    this.#lnBuf.push(...args,'\n');
    this.#logger(this.#lnBuf.join(''));
    this.#lnBuf.length = 0;
    return this;
  }

  outputPrefix(){
    if( 0==arguments.length ){
      return (this.getOutputPrefix
              ? (this.getOutputPrefix() ?? '') : '');
    }else{
      this.getOutputPrefix = arguments[0];
      return this;
    }
  }

  verboseN(lvl, argv){
    if( this.#verbosity>=lvl ){
      this.outln('VERBOSE ',lvl,': ',...argv);
    }
  }
  verbose1(...args){ return this.verboseN(1,args); }
  verbose2(...args){ return this.verboseN(2,args); }
  verbose3(...args){ return this.verboseN(3,args); }

  verbosity(){
    let rc;
    if(arguments.length){
      rc = this.#verbosity;
      this.#verbosity = arguments[0];
    }else{
      rc = this.#verbosity;
    }
    return rc;
  }

}/*Outer*/

class SQLTester {

  #outer = new Outer().outputPrefix( ()=>'SQLTester: ' );
  #aFiles = [];
  #inputBuffer = [];
  #resultBuffer = [];
  #nullView = "nil";
  #metrics = newObj({
    nTotalTest: 0, nTestFile: 0, nAbortedScript: 0
  });
  #emitColNames = false;
  #keepGoing = false;
  #db = newObj({
    list: new Array(7),
    iCurrentDb: 0,
    initialDbName: "test.db",
    initSql: ['select 1;'],
    currentDb: function(){
      return this.list[this.iCurrentDb];
    }
  });

  constructor(){
  }

  outln(...args){ return this.#outer.outln(...args); }
  out(...args){ return this.#outer.out(...args); }

  reset(){
    this.clearInputBuffer();
    this.clearResultBuffer();
    this.#clearBuffer(this.#db.initSql);
    this.closeAllDbs();
    this.nTest = 0;
    this.nullView = "nil";
    this.emitColNames = false;
    this.#db.iCurrentDb = 0;
    this.#db.initSql.push("SELECT 1;");
  }

  appendInput(line, addNL){
    this.#inputBuffer.push(line);
    if( addNL ) this.#inputBuffer.push('\n');
  }
  appendResult(line, addNL){
    this.#resultBuffer.push(line);
    if( addNL ) this.#resultBuffer.push('\n');
  }

  #clearBuffer(buffer){
    buffer.length = 0;
    return buffer;
  }

  clearInputBuffer(){ return this.#clearBuffer(this.#inputBuffer); }
  clearResultBuffer(){return this.#clearBuffer(this.#resultBuffer); }

  getInputText(){ return this.#inputBuffer.join(''); }
  getResultText(){ return this.#resultBuffer.join(''); }

  #takeBuffer(buffer){
    const s = buffer.join('');
    buffer.length = 0;
    return s;
  }

  takeInputBuffer(){
    return this.#takeBuffer(this.#inputBuffer);
  }
  takeResultBuffer(){
    return this.#takeBuffer(this.#resultBuffer);
  }

  verbosity(...args){ return this.#outer.verbosity(...args); }

  nullValue(){
    if( 0==arguments.length ){
      return this.#nullView;
    }else{
      this.#nullView = ''+arguments[0];
    }
  }

  outputColumnNames(){
    if( 0==arguments.length ){
      return this.#emitColNames;
    }else{
      this.#emitColNames = !!arguments[0];
    }
  }

  currentDbId(){
    if( 0==arguments.length ){
      return this.#db.iCurrentDb;
    }else{
      this.#affirmDbId(arguments[0]).#db.iCurrentDb = arguments[0];
    }
  }

  #affirmDbId(id){
    if(id<0 || id>=this.#db.list.length){
      toss(SQLTesterException, "Database index ",id," is out of range.");
    }
    return this;
  }

  currentDb(...args){
    if( 0!=args.length ){
      this.#affirmDbId(id).#db.iCurrentDb = id;
    }
    return this.#db.currentDb();
  }

  getDbById(id){
    return this.#affirmDbId(id).#db.list[id];
  }

  getCurrentDb(){ return this.#db.list[this.#db.iCurrentDb]; }


  closeDb(id) {
    if( 0==arguments.length ){
      id = this.#db.iCurrentDb;
    }
    const db = this.#affirmDbId(id).#db.list[id];
    if( db ){
      sqlite3.capi.sqlite3_close_v2(db);
      this.#db.list[id] = null;
    }
  }

  closeAllDbs(){
    for(let i = 0; i<this.#db.list.length; ++i){
      if(this.#db.list[i]){
        sqlite3.capi.sqlite3_close_v2(this.#db.list[i]);
        this.#db.list[i] = null;
      }
    }
    this.#db.iCurrentDb = 0;
  }

  openDb(name, createIfNeeded){
    if( 3===arguments.length ){
      const slot = arguments[0];
      this.#affirmDbId(slot).#db.iCurrentDb = slot;
      name = arguments[1];
      createIfNeeded = arguments[2];
    }
    this.closeDb();
    const capi = sqlite3.capi, wasm = sqlite3.wasm;
    let pDb = 0;
    let flags = capi.SQLITE_OPEN_READWRITE;
    if( createIfNeeded ) flags |= capi.SQLITE_OPEN_CREATE;
    try{
      let rc;
      wasm.pstack.call(function(){
        let ppOut = wasm.pstack.allocPtr();
        rc = sqlite3.capi.sqlite3_open_v2(name, ppOut, flags, null);
        pDb = wasm.peekPtr(ppOut);
      });
      if( 0==rc && this.#db.initSql.length > 0){
        //this.#outer.verbose2("RUNNING DB INIT CODE: ",this.#db.initSql.toString());
        rc = this.execSql(pDb, false, ResultBufferMode.NONE,
                          null, this.#db.initSql.join(''));
      }
      if( 0!=rc ){
        sqlite3.SQLite3Error.toss(
          rc,
          "sqlite3 result code",rc+":",
          (pDb ? sqlite3.capi.sqlite3_errmsg(pDb)
           : sqlite3.capi.sqlite3_errstr(rc))
        );
      }
      return this.#db.list[this.#db.iCurrentDb] = pDb;
    }catch(e){
      sqlite3.capi.sqlite3_close_v2(pDb);
      throw e;
    }
  }

  #setupInitialDb(){
    if( !this.#db.list[0] ){
      Util.unlink(this.#db.initialDbName);
      this.openDb(0, this.#db.initialDbName, true);
    }else{
      this.#outer.outln("WARNING: setupInitialDb() unexpectedly ",
                        "triggered while it is opened.");
    }
  }

  /**
     Returns v or some escaped form of v, as defined in the tester's
     spec doc.
  */
  #escapeSqlValue(v){
    if( !v ) return "{}";
    if( !Rx.special.test(v) ){
      return v  /* no escaping needed */;
    }
    if( !Rx.squiggly.test(v) ){
      return "{"+v+"}";
    }
    const sb = ["\""];
    const n = v.length;
    for(let i = 0; i < n; ++i){
      const ch = v.charAt(i);
      switch(ch){
        case '\\': sb.push("\\\\"); break;
        case '"': sb.push("\\\""); break;
        default:{
          //verbose("CHAR ",(int)ch," ",ch," octal=",String.format("\\%03o", (int)ch));
          const ccode = ch.charCodeAt(i);
          if( ccode < 32 ) sb.push('\\',ccode.toString(8),'o');
          else sb.push(ch);
          break;
        }
      }
    }
    sb.append("\"");
    return sb.join('');
  }

  #appendDbErr(pDb, sb, rc){
    sb.push(sqlite3.capi.sqlite3_js_rc_str(rc), ' ');
    const msg = this.#escapeSqlValue(sqlite3.capi.sqlite3_errmsg(pDb));
    if( '{' == msg.charAt(0) ){
      sb.push(msg);
    }else{
      sb.push('{', msg, '}');
    }
  }

  execSql(pDb, throwOnError, appendMode, lineMode, sql){
    sql = sqlite3.capi.sqlite3_js_sql_to_string(sql);
    this.#outer.outln("execSql() is TODO. ",sql);
    return 0;
  }

}/*SQLTester*/

class Command {
  constructor(){
  }

  process(sqlTester,testScript,argv){
    SQLTesterException.toss("process() must be overridden");
  }

  argcCheck(testScript,argv,min,max){
    const argc = argv.length-1;
    if(argc<min || (max>=0 && argc>max)){
      if( min==max ){
        testScript.toss(argv[0]," requires exactly ",min," argument(s)");
      }else if(max>0){
        testScript.toss(argv[0]," requires ",min,"-",max," arguments.");
      }else{
        testScript.toss(argv[0]," requires at least ",min," arguments.");
      }
    }
  }
}

class Cursor {
  src;
  sb = [];
  pos = 0;
  //! Current line number. Starts at 0 for internal reasons and will
  // line up with 1-based reality once parsing starts.
  lineNo = 0 /* yes, zero */;
  //! Putback value for this.pos.
  putbackPos = 0;
  //! Putback line number
  putbackLineNo = 0;
  //! Peeked-to pos, used by peekLine() and consumePeeked().
  peekedPos = 0;
  //! Peeked-to line number.
  peekedLineNo = 0;

  constructor(){
  }

  //! Restore parsing state to the start of the stream.
  rewind(){
    this.sb.length = this.pos = this.lineNo
      = this.putbackPos = this.putbackLineNo
      = this.peekedPos = this.peekedLineNo = 0;
  }
}

const Rx = newObj({
  requiredProperties: / REQUIRED_PROPERTIES:[ \t]*(\S.*)\s*$/,
  scriptModuleName: / SCRIPT_MODULE_NAME:[ \t]*(\S+)\s*$/,
  mixedModuleName: / ((MIXED_)?MODULE_NAME):[ \t]*(\S+)\s*$/,
  command: /^--(([a-z-]+)( .*)?)$/,
  //! "Special" characters - we have to escape output if it contains any.
  special: /[\x00-\x20\x22\x5c\x7b\x7d]/,
  //! Either of '{' or '}'.
  squiggly: /[{}]/
});

class TestScript {
  #cursor = new Cursor();
  #moduleName = null;
  #filename = null;
  #testCaseName = null;
  #outer = new Outer().outputPrefix( ()=>this.getOutputPrefix()+': ' );

  constructor(...args){
    let content, filename;
    if( 2 == args.length ){
      filename = args[0];
      content = args[1];
    }else{
      content = args[0];
    }
    this.#filename = filename;
    this.#cursor.src = content;
  }

  testCaseName(){
    return (0==arguments.length)
      ? this.#testCaseName : (this.#testCaseName = arguments[0]);
  }

  getOutputPrefix() {
    let rc =  "["+(this.#moduleName || this.#filename)+"]";
    if( this.#testCaseName ) rc += "["+this.#testCaseName+"]";
    return rc + " line "+ this.#cursor.lineNo;
  }

  reset(){
    this.#testCaseName = null;
    this.#cursor.rewind();
    return this;
  }

  toss(...args){
    throw new TestScriptFailed(this,...args);
  }

  #checkForDirective(tester,line){
    //todo
  }

  #getCommandArgv(line){
    const m = Rx.command.exec(line);
    return m ? m[1].trim().split(/\s+/) : null;
  }

  run(tester){
    this.reset();
    this.#outer.verbosity(tester.verbosity());
    let line, directive, argv = [];
    while( null != (line = this.getLine()) ){
      this.verbose3("input line: ",line);
      this.#checkForDirective(tester, line);
      argv = this.#getCommandArgv(line);
      if( argv ){
        this.#processCommand(tester, argv);
        continue;
      }
      tester.appendInput(line,true);
    }
    return true;
  }

  #processCommand(tester, argv){
    this.verbose1("running command: ",argv[0], " ", Util.argvToString(argv));
    if(this.#outer.verbosity()>1){
      const input = tester.getInputText();
      if( !!input ) this.verbose3("Input buffer = ",input);
    }
    CommandDispatcher.dispatch(tester, this, argv);
  }

  getLine(){
    const cur = this.#cursor;
    if( cur.pos==cur.src.byteLength ){
      return null/*EOF*/;
    }
    cur.putbackPos = cur.pos;
    cur.putbackLineNo = cur.lineNo;
    cur.sb.length = 0;
    let b = 0, prevB = 0, i = cur.pos;
    let doBreak = false;
    let nChar = 0 /* number of bytes in the aChar char */;
    const end = cur.src.byteLength;
    for(; i < end && !doBreak; ++i){
      b = cur.src[i];
      switch( b ){
        case 13/*CR*/: continue;
        case 10/*NL*/:
          ++cur.lineNo;
          if(cur.sb.length>0) doBreak = true;
          // Else it's an empty string
          break;
        default:{
          /* Multi-byte chars need to be gathered up and appended at
             one time so that we can get them as string objects. */
          nChar = 1;
          switch( b & 0xF0 ){
            case 0xC0: nChar = 2; break;
            case 0xE0: nChar = 3; break;
            case 0xF0: nChar = 4; break;
            default:
              if( b > 127 ) this.toss("Invalid character (#"+b+").");
              break;
          }
          if( 1==nChar ){
            cur.sb.push(String.fromCharCode(b));
          }else{
            const aChar = [] /* multi-byte char buffer */;
            for(let x = 0; (x < nChar) && (i+x < end); ++x) aChar[x] = cur.src[i+x];
            cur.sb.push(
              Util.utf8Decode( new Uint8Array(aChar) )
            );
            i += nChar-1;
          }
          break;
        }
      }
    }
    cur.pos = i;
    const rv = cur.sb.join('');
    if( i==cur.src.byteLength && 0==rv.length ){
      return null /* EOF */;
    }
    return rv;
  }/*getLine()*/

  /**
     Fetches the next line then resets the cursor to its pre-call
     state. consumePeeked() can be used to consume this peeked line
     without having to re-parse it.
  */
  peekLine(){
    const cur = this.#cursor;
    const oldPos = cur.pos;
    const oldPB = cur.putbackPos;
    const oldPBL = cur.putbackLineNo;
    const oldLine = cur.lineNo;
    const rc = this.getLine();
    cur.peekedPos = cur.pos;
    cur.peekedLineNo = cur.lineNo;
    cur.pos = oldPos;
    cur.lineNo = oldLine;
    cur.putbackPos = oldPB;
    cur.putbackLineNo = oldPBL;
    return rc;
  }


  /**
     Only valid after calling peekLine() and before calling getLine().
     This places the cursor to the position it would have been at had
     the peekLine() had been fetched with getLine().
  */
  consumePeeked(){
    const cur = this.#cursor;
    cur.pos = cur.peekedPos;
    cur.lineNo = cur.peekedLineNo;
  }

  /**
     Restores the cursor to the position it had before the previous
     call to getLine().
  */
  putbackLine(){
    const cur = this.#cursor;
    cur.pos = cur.putbackPos;
    cur.lineNo = cur.putbackLineNo;
  }

  verbose1(...args){ return this.#outer.verboseN(1,args); }
  verbose2(...args){ return this.#outer.verboseN(2,args); }
  verbose3(...args){ return this.#outer.verboseN(3,args); }
  verbosity(...args){ return this.#outer.verbosity(...args); }

}/*TestScript*/;

//! --close command
class CloseDbCommand extends Command {
  process(t, ts, argv){
    this.argcCheck(ts,argv,0,1);
    let id;
    if(argv.length>1){
      const arg = argv[1];
      if("all".equals(arg)){
        t.closeAllDbs();
        return;
      }
      else{
        id = parseInt(arg);
      }
    }else{
      id = t.currentDbId();
    }
    t.closeDb(id);
  }
}

//! --column-names command
class ColumnNamesCommand extends Command {
  process( st, ts, argv ){
    this.argcCheck(ts,argv,1);
    st.outputColumnNames( !!parseInt(argv[1]) );
  }
}

//! --db command
class DbCommand extends Command {
  process(t, ts, argv){
    this.argcCheck(ts,argv,1);
    t.currentDbId( parseInt(argv[1]) );
  }
}

//! --open command
class OpenDbCommand extends Command {
  #createIfNeeded = false;
  constructor(createIfNeeded=false){
    super();
    this.#createIfNeeded = createIfNeeded;
  }
  process(t, ts, argv){
    this.argcCheck(ts,argv,1);
    t.openDb(argv[1], this.#createIfNeeded);
  }
}

//! --new command
class NewDbCommand extends OpenDbCommand {
  constructor(){ super(true); }
}

//! Placeholder dummy/no-op commands
class NoopCommand extends Command {
  process(t, ts, argv){}
}

//! --null command
class NullCommand extends Command {
  process(st, ts, argv){
    this.argcCheck(ts,argv,1);
    st.nullValue( argv[1] );
  }
}

//! --print command
class PrintCommand extends Command {
  process(st, ts, argv){
    st.out(ts.getOutputPrefix(),': ');
    if( 1==argv.length ){
      st.out( st.getInputText() );
    }else{
      st.outln( Util.argvToString(argv) );
    }
  }
}


//! --testcase command
class TestCaseCommand extends Command {
  process(tester, script, argv){
    this.argcCheck(script, argv,1);
    script.testCaseName(argv[1]);
    tester.clearResultBuffer();
    tester.clearInputBuffer();
  }
}


//! --verbosity command
class VerbosityCommand extends Command {
  process(t, ts, argv){
    t.argcCheck(ts,argv,1);
    ts.verbosity( parseInt(argv[1]) );
  }
}

class CommandDispatcher {
  static map = newObj();

  static getCommandByName(name){
    let rv = CommandDispatcher.map[name];
    if( rv ) return rv;
    switch(name){
      case "close":        rv = new CloseDbCommand(); break;
      case "column-names": rv = new ColumnNamesCommand(); break;
      case "db":           rv = new DbCommand(); break;
      //case "glob":         rv = new GlobCommand(); break;
      //case "json":         rv = new JsonCommand(); break;
      //case "json-block":   rv = new JsonBlockCommand(); break;
      case "new":          rv = new NewDbCommand(); break;
      //case "notglob":      rv = new NotGlobCommand(); break;
      case "null":         rv = new NullCommand(); break;
      case "oom":          rv = new NoopCommand(); break;
      case "open":         rv = new OpenDbCommand(); break;
      case "print":        rv = new PrintCommand(); break;
      //case "result":       rv = new ResultCommand(); break;
      //case "run":          rv = new RunCommand(); break;
      //case "tableresult":  rv = new TableResultCommand(); break;
      case "testcase":     rv = new TestCaseCommand(); break;
      case "verbosity":    rv = new VerbosityCommand(); break;
    }
    if( rv ){
      CommandDispatcher.map[name] = rv;
    }
    return rv;
  }

  static dispatch(tester, testScript, argv){
    const cmd = CommandDispatcher.getCommandByName(argv[0]);
    if( !cmd ){
      toss(UnknownCommand,argv[0],' ',testScript.getOutputPrefix());
    }
    cmd.process(tester, testScript, argv);
  }
}/*CommandDispatcher*/

const namespace = newObj({
  Command,
  DbException,
  IncompatibleDirective,
  Outer,
  SQLTester,
  SQLTesterException,
  TestScript,
  TestScriptFailed,
  UnknownCommand,
  Util,
  sqlite3
});

export {namespace as default};