const WAIT_LOCK    = 1
const READ_LOCK    = 2
const WAIT_HOLE    = 3
const READ_HOLE    = 4
const WAIT_KEY     = 5
const READ_KEY     = 6

const STATE = ["", "WAIT_LOCK", "READ_LOCK", "WAIT_HOLE", "READ_HOLE", "WAIT_KEY", "READ_KEY"]
const PASSHOLE = ["text", "off"]
const space = " ".charCodeAt();
const tab = "\t".charCodeAt();
const zero = "0".charCodeAt();
const nine = "9".charCodeAt();
const a = "a".charCodeAt();
const f = "f".charCodeAt();
const conv = new TextEncoder();

const findIndex = (t, tr) => {
    const tlen = t.length, rlen = tr.length;
    for( let i=0; i+rlen < tlen; ++i ){
	let eq = true;
        for( j=0; j < rlen; ++j ){
            if( t[i+j] != tr[j] ){
                eq = false;
                break;
            }
        } 
        if( eq && t[i+rlen]==0 ) return i;
    }
    return -1;
}

const read = (cht, info, order) => {
    cht = cht.replace( /[-]{4,}/g, "" );
    const size = cht.length;
    let   state = WAIT_LOCK, token = [], line = 1;

    let locks = [], currlock = null;
    const token_str = () => { let r = String.fromCharCode.apply( String, token ); return (token.length=0,r);}
    const error = msg => { throw new SyntaxError(`${msg} at line: ${line} in lock ${currlock?.name}`) }
    for( let i=0; i <= size; ++i ){
        const ch = i == size ? "" : cht.charAt(i);
        switch( ch ){
            case "[":
                if( state == WAIT_LOCK || state == READ_HOLE ){
                    state = READ_LOCK;
                    if( currlock ) locks.push( { name: currlock.name, keys: currlock.holes } );
                    currlock = {}
                }
                else error(`error occur [ on ${STATE[state]}`)
            break;
            case "]":
                if( state == READ_LOCK ){
                    state = WAIT_HOLE;
                    currlock.name = token_str();
                    currlock.holes = [];
                    if( currlock.name.toLowerCase() == "gameinfo" )
                    	i = size;		// break;
                }
                else error(`error occur ] on ${STATE[state]}`)
            break;
            case "\r": case "\n":
                if( state == WAIT_HOLE ){
                    state = READ_HOLE;
                }
                else if( state == READ_KEY ){
                    state = READ_HOLE;
                    if( token.length ) currlock.keys.at(-1).push( token_str() );
                    if( !PASSHOLE.includes(currlock.hole.toLowerCase()) ) {
                        currlock.holes.push( {name: currlock.hole, cmd: currlock.keys} );
                    }
                }
                else if( state == READ_LOCK ){
                    error(`error occur newline on ${STATE[state]}`);
                }
                else if( state == READ_HOLE ){
                    if( token.length > 0 && token.find( c => c!=space && c!=tab ) ){ 
                        error(`error occur newline on ${STATE[state]}`);
                    }
                    else token.length = 0;
                }
                if( ch == "\n" ) ++line;
            break;
            case "=":
                if( state == READ_HOLE ){
                    state = READ_KEY;
                    currlock.hole = token_str();
                    currlock.keys = [ new Array() ];
                }
                else if( state == READ_LOCK ){
                    token.push( ch.charCodeAt() );
                }
                else error(`error occur = on ${STATE[state]}`);
            break;
            case ",":
                if( state == READ_KEY ){
                    if( token.length ) currlock.keys.at(-1).push( token_str() );
                }
                else if( state == READ_HOLE ){// MULTILINE KEY
                    let {name, cmd} = currlock.holes.pop();
                    currlock.hole = name;
                    currlock.keys = cmd;
                    if( token.length ) currlock.keys.at(-1).push( token_str() );
                    state = READ_KEY;
                }
                else if( state == READ_LOCK ){
                    token.push( ch.charCodeAt() );
                }
                else error(`error occur , on ${STATE[state]}`);
            break;
            case ";":
                if( state == READ_KEY ){
                    if( token.length ) currlock.keys.at(-1).push( token_str() );
                    currlock.keys.push( new Array() );
                }
                else if( state == READ_LOCK ){
                    token.push( ch.charCodeAt() );
                }
                else if( state == READ_HOLE ){// MULTILINE KEY
                    let {name, cmd} = currlock.holes.pop();
                    currlock.hole = name;
                    currlock.keys = cmd;
                    if( token.length ) currlock.keys.at(-1).push( token_str() );
                    currlock.keys.push( new Array() );
                    state = READ_KEY;
                }
                else error(`error occur ; on ${STATE[state]}`);
            break;
            case "": // END OF FILE
                if( state == READ_KEY ){
                    if( token.length ) currlock.keys.at(-1).push( token_str() );
                }
                else if( state == READ_HOLE && token.length == 0 ){
                    // safe
                }
                else error(`error occur eof on ${STATE[state]}`)
            break;
            case " ":
                if( state == READ_LOCK || state == READ_HOLE ){
                    token.push( ch.charCodeAt() );
                }
                else if( state == READ_KEY ){
                    if( currlock.name.toLowerCase() == "gameinfo" ){
                        token.push( ch.charCodeAt() );
                    }
                }
            break;
            default:
                if( state == READ_LOCK || state == READ_HOLE ){
                    token.push( ch.charCodeAt() );
                }
                else if( state == READ_KEY ){
                    let digit = ch.toLowerCase().charCodeAt();
                    if( (zero <= digit && digit <= nine) ||
                        (a <= digit && digit <= f) || 
                        currlock.name.toLowerCase() == "gameinfo" ||
                        currlock.hole.toLowerCase() == "text" ) 
                    {
                        token.push( digit );
                    }
                    else error( `error occur ${ch}[${digit}] on ${STATE[state]}` );
                }
                else error(`error occur ${ch} on ${STATE[state]}`);
            break;
        }
    }
    return lade( locks, info, order );
}

const assembleCheat = (list, dup, hole) => {
  // 建立 地址:数值 的映射关系
  const fromTaddr = taddr => {
    const n = parseInt(taddr, 16);
    if( n==0 || n>0x41FFFFF ) throw new Error( `get a invalid address: ${taddr}` );
    if( n <= 0x3ffff ) return n | 0x2000000;
    else if( 0 == (n & 0xf000000) ) return (n & 0xffff) | 0x3000000;
    else return n;
  };
  const addrval = list.reduce( (r, command) => {
    let [taddr, ...vals] = command;
    let addr = fromTaddr( taddr );
    vals.forEach( (val, pos) => {
      let dest = addr + pos;
      let value = parseInt(val, 16);
      r.set( dest, value );
    } );
    return r;
  }, new Map() );
  const ordered = [...addrval].sort( (a,b) => a[0] - b[0] );
  const blocks = ordered.reduce( (arr, [addr, value]) => {
    dup.set(addr, hole);
    if( arr.length == 0 ) {
      arr.push({addr, value, count: 1});// cnt addr value
    }
    else {
      let cur = arr.at(-1);
      if( cur.value == value ){
        ++cur.count;
      }
      else arr.push( {addr, value, count: 1} );
    }
    return arr;
  }, [] );
  return Uint32Array.from( blocks.reduce( (r,block)=>[...r, block.addr, (block.count<<8)|block.value], []) )
}

const pack = (entlist, strlist, idxlist, cmdlist, xvalue) => {
  const align = (n, base) => base * Math.floor( (n+base-1) / base );
  const entrysize = entlist[0].buffer.byteLength;
  const strbase = 2 + entlist.length * entrysize;
  const idxbase = strbase + strlist.buffer.byteLength;
  const cmdbase = idxbase + idxlist.buffer.byteLength;
  const size = cmdbase + cmdlist.buffer.byteLength;;
  let result = new ArrayBuffer( align(size, 32) );

  // entry count
  let view = new DataView(result);
  view.setUint16(0, entlist.length, true);

  // entry data
  entlist.forEach( (entry,index) => {
    let offset = 2 + index*entrysize;
    view.setUint32( offset, entry[0], true );
    view.setUint32( offset+4, entry[1] + (entry[0] > 0xffff ? cmdbase : idxbase), true );
    view.setUint32( offset+8, entry[2], true );
  });

  // string table
  let strings = new Uint8Array( result, strbase, strlist.length );
  strings.set( strlist, 0 );

  // indexes table
  let indexes = new Uint8Array( result, idxbase, idxlist.buffer.byteLength );
  indexes.set( new Uint8Array(idxlist.buffer), 0 );

  // instruction table
  let commands = new Uint8Array( result, cmdbase, cmdlist.buffer.byteLength );
  commands.set( new Uint8Array(cmdlist.buffer), 0 );

  return { id: xvalue, bin: new Uint8Array( result ) };
}

const lade = (list, info, order) => {
  let enttable = []; // 保存hole/key数据

  const makeID = (a,b) => a|b<<16;
  const makeEntry = (id, str) => ({ id, data: str }); 

  // collect
  const collectEntry = (id, keys, list) => {
    keys.forEach( ({name,cmd}, index) => {
      list.push( name );
      enttable.push( makeEntry( makeID(id,index+1), cmd ) );
    });
  }

  let rootstr = [];
  list.forEach( (hole,index) => {
    rootstr.push( hole.name );

    let holestr = [];
    collectEntry( index+1, hole.keys, holestr );
    
    let entry = makeEntry( makeID(index+1,0), holestr );
    enttable.push( entry );
  } );
  enttable.push( makeEntry( makeID(0,0), rootstr ) );

  enttable.sort( (a,b) => a.id - b.id );

  let strtable = Uint8Array.of(); // 保存字符串常量
  let idxtable = Uint16Array.of(); // 从字符串常量索引出来的字符串列表
  let cmdtable = Uint32Array.of(); // 保存选项对应指令
  const addString = list => {
    const ut_pushtr = tr => {
      const off = strtable.length;
      let nt = new Uint8Array( off+tr.length+1 );
      nt.set( strtable, 0 );
      nt.set( tr, off );
      strtable = nt;
      return off;
    };
    const ut_addtr = tr => {
      const code = conv.encode( tr );
      const off = findIndex( strtable, code );
      return off < 0 ? ut_pushtr( code ) : off;
    };
    return list.map( ut_addtr );
  }

  const addStrIndex = list => {
    if( list.length == 0 ) return 0;

    if( strtable.length > 0xffff ) throw new RangeError(`string table is too big.`);
    let ret = idxtable.buffer.byteLength;
    let nt = new Uint16Array( idxtable.length + list.length );
    nt.set( idxtable, 0 );
    nt.set( list, idxtable.length );
    idxtable = nt;
    return ret;
  }

  const addCommand = list => {
    let ret = cmdtable.buffer.byteLength;
    let nt = new Uint32Array( cmdtable.length + list.length );
    nt.set( cmdtable, 0 );
    nt.set( list, cmdtable.length );
    cmdtable = nt;
    return ret;
  }
  
  if( enttable.length > 0xffff ){
    console.warn(`entry 数量超过上限[file=${order}]`);
  }

  // pack
  let holedup = new Map();
  let entbytelist = enttable.map( entry => {
    let {id, data} = entry;
    if( id < 0x10000 ){ // 收集str
      let idxlist = addString(data.length > 1 ? data : []); // length==1就是开启
      let location = addStrIndex( idxlist );
      return Uint32Array.of( id, location, idxlist.length );
    }
    else {
      let armbytecode = assembleCheat( data, holedup, id & 0xffff );
      let location = addCommand( armbytecode );
      return Uint32Array.of( id, location, armbytecode.length );
    }
  });

  let n = info.serial.split("").reduce( (r,v)=>(v.charCodeAt() | r<<8), 0 );
  let xv = cmdtable.reduce( (r,v) => r^v, n );
  return pack( entbytelist, strtable, idxtable, cmdtable, xv );
}

module.exports = read;