/* JSON parser */
var JsonTypeNull = 0;;
var JsonTypeString = 1;;
var JsonTypeNumber = 2;;
var JsonTypeBool = 3;;
var JsonTypeObject = 4;;
var JsonTypeArray = 5;;

struct JsonValue = [
  JSONV_iType      : I,
  JSONV_sValue     : S,
  JSONV_fValue     : F,
  JSONV_bValue     : I,
  JSONV_object     : [[S JsonValue] r1],
  JSONV_array      : [JsonValue r1]
  
  ]mkJsonValue;;

struct JsonData = [
  JSOND_sContent   : S,
  JSOND_ipos       : I
  
  ]mkJsonData;;

proto parseJsonValue = fun [JsonData] JsonValue;;

fun getCurJsonChar(jsdata)=
  nth_char jsdata.JSOND_sContent jsdata.JSOND_ipos;;


fun skipJsonWhitespace(jsdata)=
  let strlen jsdata.JSOND_sContent -> lenght in
  while ((jsdata.JSOND_ipos < lenght) && (isSpace (getCurJsonChar jsdata))) do
    set jsdata.JSOND_ipos = jsdata.JSOND_ipos + 1;
  jsdata.JSOND_ipos;;


fun getNextJsonChar(jsdata)=
  let getCurJsonChar jsdata -> c in
  (
    set jsdata.JSOND_ipos = jsdata.JSOND_ipos + 1;
    c;
  );;


fun getNextJsonCharWithSkip(jsdata)=
  skipJsonWhitespace jsdata;
  getNextJsonChar jsdata;;


fun exportJson(jsvalue)=
  let "" -> result in
  (
    if (jsvalue.JSONV_iType == JsonTypeString) then
      set result = strcatn "\""::(protectParam strtoutf8 jsvalue.JSONV_sValue)::"\""::nil
    else if (jsvalue.JSONV_iType == JsonTypeNumber) then
      set result = getShortFloatToString jsvalue.JSONV_fValue
    else if (jsvalue.JSONV_iType == JsonTypeObject) then
    (
      set result = "{";
      let jsvalue.JSONV_object -> l in
      let 0 -> pos in
      while (l != nil) do
      (
        let hd l -> [key element] in
        (
          if (pos == 0) then nil else
            set result = strcat result ",";
          
          set result = strcat result strcatn "\""::key::"\": "::(exportJson element)::nil;
        );
        set l = tl l;
        set pos = pos + 1;
      );
      set result = strcat result "}";
    )
    else if (jsvalue.JSONV_iType == JsonTypeArray) then
    (
      set result = "[";
      let jsvalue.JSONV_array -> l in
      let 0 -> pos in
      while (l != nil) do
      (
        let hd l -> element in
        (
          if (pos == 0) then nil else
            set result = strcat result ",";
          
          set result = strcat result (exportJson element);
        );
        set l = tl l;
        set pos = pos + 1;
      );
      set result = strcat result "]";
    )
    else if (jsvalue.JSONV_iType == JsonTypeBool) then
      set result = if jsvalue.JSONV_bValue then "true" else "false"
    else if (jsvalue.JSONV_iType == JsonTypeNull) then
      set result = "null"
    else nil;
    
    result;
  );;


fun parseJsonString(jsdata)=
  //addLogMessage "parseJsonString";
  let "" -> value in
  (
    let -1 -> c in
    let strlen jsdata.JSOND_sContent -> lenght in
    while ((jsdata.JSOND_ipos < lenght) && ((set c = getNextJsonChar jsdata) != 34)) do //"
    (
      if (c == 92) then // \
      (
        // Handle escape characters
        let getNextJsonChar jsdata -> escaped in
        if (escaped == 110) then //n
          set value = strcat value "\n"
        else if (escaped == 116) then //t
          set value = strcat value "\t"
        else
          set value = strcat value ctoa escaped;
      )
      else
        set value = strcat value ctoa c;
    );
    
    mkJsonValue [JsonTypeString utf8tostr value 0.0 0 nil nil];
  );;


fun parseJsonNumber(jsdata)=
  //addLogMessage "parseJsonNumber";
  let "" -> value in
  (
    let -1 -> c in
    let strlen jsdata.JSOND_sContent -> lenght in
    while ((jsdata.JSOND_ipos < lenght) && ((isDigit (getCurJsonChar jsdata)) || (getCurJsonChar jsdata) == 46)) do
    (
      let getNextJsonChar jsdata -> c in
        set value = strcat value ctoa c;
    );
    mkJsonValue [JsonTypeNumber "" (atof value) 0 nil nil];
  );;


fun parseJsonObject(jsdata)=
  //addLogMessage "parseJsonObject";
  let nil -> jobject in // [S JsonValue] r1
  let 0 -> error in
  (
    let -1 -> c in    
    let strlen jsdata.JSOND_sContent -> lenght in
    while (!error && (jsdata.JSOND_ipos < lenght) && ((set c = getNextJsonCharWithSkip jsdata) != 125)) do //}
    (
      if (c == 34) then //"
      (
        // Parse key
        let parseJsonString jsdata -> key in
        (
          //addLogMessage strcat "key > " key.JSONV_sValue;
          // Expect colon
          if ((getNextJsonCharWithSkip jsdata) == 58) then nil else //:
          (
            addLogMessage "JsonParser error: Expected colon in object.";            
            //addLogMessage itoa getCurJsonChar jsdata;
            set error = 1;
          );
          
          // Parse value
          let parseJsonValue jsdata -> value in
            set jobject = lcat jobject [key.JSONV_sValue value]::nil;
        );
        
        // Check for more items or end of object
        skipJsonWhitespace jsdata;
        if ((getCurJsonChar jsdata) == 44) then //,
        (
          getNextJsonCharWithSkip jsdata;
        )
        else if ((getCurJsonChar jsdata) != 125) then //}
        (
          addLogMessage "JsonParser error: Expected comma or end of object.";
          //addLogMessage itoa getCurJsonChar jsdata;
          set error = 1;
        )
        else nil;
        0;
      )
      else
      (
        addLogMessage "JsonParser error: Expected string key in object.";
        //addLogMessage itoa c;
        set error = 1;
      );
    );
    
    mkJsonValue [JsonTypeObject "" 0.0 0 jobject nil];
  );;


fun parseJsonArray(jsdata)=
  //addLogMessage "parseJsonArray";
  let nil -> jarray in // [S JsonValue] r1
  let 0 -> error in
  (
    let -1 -> c in
    let strlen jsdata.JSOND_sContent -> lenght in
    while (!error && (jsdata.JSOND_ipos < lenght) && (set c = getNextJsonChar jsdata) != 93) do //]
    (
      let parseJsonValue jsdata -> element in
        set jarray = lcat jarray element::nil;
      
      // Check for more items or end of array
      skipJsonWhitespace jsdata;
      
      if ((getCurJsonChar jsdata) == 44) then //,
      (
        getNextJsonCharWithSkip jsdata;
      )
      else if ((getCurJsonChar jsdata) != 93) then //]
      (
        addLogMessage "JsonParser error: Expected comma or end of array.";
        set error = 1;
      )
      else nil;
    );
    
    mkJsonValue [JsonTypeArray "" 0.0 0 nil jarray];
  );;


fun parseJsonValue(jsdata)=
  //addLogMessage "parseJsonValue";
  let getNextJsonCharWithSkip jsdata -> c in
  if (c == 34) then //"
    parseJsonString jsdata
  else if (isDigit c || c == 45) then //-
    parseJsonNumber jsdata
  else if (c == 123) then //{
    parseJsonObject jsdata
  else if (c == 91) then //[
    parseJsonArray jsdata
  else if (isAlpha c) then
  let ctoa c -> word in
  (
    // Parse true, false, or null
    while (isAlpha (getCurJsonChar jsdata)) do
    (
      set word = strcat word ctoa (getNextJsonChar jsdata);
    );
    
    if (!strcmpi word "true") then
      mkJsonValue [JsonTypeBool "" 0.0 1 nil nil]
    else if (!strcmpi word "false") then      
      mkJsonValue [JsonTypeBool "" 0.0 0 nil nil]
    else if (!strcmpi word "null") then
      mkJsonValue [JsonTypeNull "" 0.0 0 nil nil]
    else
    (      
      addLogMessage strcat "JsonParser error: Invalid keyword in JSON. Word found: " word;
      nil;
    );
  )
  else
  (
    addLogMessage "JsonParser error: Unexpected character in JSON.";
    //addLogMessage itoa c;
    nil;
  );;


fun getJsonObjectValue(jvalue, name)=
  if ((jvalue.JSONV_iType) != JsonTypeObject) then nil else
    switchstr jvalue.JSONV_object name;;


fun getJsonArray(jvalue)=
  if ((jvalue.JSONV_iType) != JsonTypeArray) then nil else
    jvalue.JSONV_array;;


fun getJsonString(jvalue)=
  if ((jvalue.JSONV_iType) != JsonTypeString) then nil else
    jvalue.JSONV_sValue;;


fun getJsonBoolean(jvalue)=
  if ((jvalue.JSONV_iType) != JsonTypeBool) then nil else
    jvalue.JSONV_bValue;;


fun getJsonFloat(jvalue)=
  if ((jvalue.JSONV_iType) != JsonTypeNumber) then nil else
    jvalue.JSONV_fValue;;


fun getJsonInt(jvalue)=
  if ((jvalue.JSONV_iType) != JsonTypeNumber) then nil else
    ftoi jvalue.JSONV_fValue;;


fun isJsonNull(jvalue)=
  if ((jvalue.JSONV_iType) != JsonTypeNull) then 0 else
    1;;


// lvalues [S JsonValue] r1
fun makeJsonObject(lvalues)=
  mkJsonValue [JsonTypeObject "" 0.0 0 lvalues nil];;


fun makeJsonArray(larray)=
  mkJsonValue [JsonTypeArray "" 0.0 0 nil larray];;


fun makeJsonString(value)=
  mkJsonValue [JsonTypeString value 0.0 0 nil nil];;


fun makeJsonNumF(value)=
  mkJsonValue [JsonTypeNumber "" value 0 nil nil];;


fun makeJsonNum(value)=
  mkJsonValue [JsonTypeNumber "" (itof value) 0 nil nil];;


fun makeJsonBool(value)=
  mkJsonValue [JsonTypeBool "" 0.0 value nil nil];;


fun makeJsonNull(value)=
  mkJsonValue [JsonTypeNull "" 0.0 0 nil nil];;


fun parseJson(s)=
  let mkJsonData [s 0] -> jsdata in
  (
    parseJsonValue jsdata;
  );;