#include "dynos.cpp.h"

  //////////
 // Misc //
//////////

void DynOS_Gfx_Free(GfxData* aGfxData) {
    if (aGfxData) {
        for (auto& _Node : aGfxData->mLights) {
            Delete(_Node->mData);
            Delete(_Node);
        }
        for (auto& _Node : aGfxData->mTextures) {
            Delete(_Node->mData);
            Delete(_Node);
        }
        for (auto& _Node : aGfxData->mVertices) {
            Delete(_Node->mData);
            Delete(_Node);
        }
        for (auto& _Node : aGfxData->mDisplayLists) {
            Delete(_Node->mData);
            Delete(_Node);
        }
        for (auto& _Node : aGfxData->mGeoLayouts) {
            Delete(_Node->mData);
            Delete(_Node);
        }
        for (auto& _Node : aGfxData->mAnimations) {
            Delete(_Node->mData);
            Delete(_Node);
        }
        for (auto& _Node : aGfxData->mCollisions) {
            Delete(_Node->mData);
            Delete(_Node);
        }
        for (auto& _Node : aGfxData->mLevelScripts) {
            Delete(_Node->mData);
            Delete(_Node);
        }
        for (auto& _Node : aGfxData->mMacroObjects) {
            Delete(_Node->mData);
            Delete(_Node);
        }
        for (auto& _Node : aGfxData->mTrajectories) {
            Delete(_Node->mData);
            Delete(_Node);
        }
        for (auto& _Node : aGfxData->mMovtexs) {
            Delete(_Node->mData);
            Delete(_Node);
        }
        for (auto& _Node : aGfxData->mMovtexQCs) {
            Delete(_Node->mData);
            Delete(_Node);
        }
        Delete(aGfxData);
    }
}

  ///////////////////////
 // Recursive Descent //
///////////////////////

static char* sRdString = NULL;
static bool sRdError = false;

static s64 ParseExpression();

static void ParseWhitespace() {
    while (*sRdString == ' ' || *sRdString == '\t' || *sRdString == '\r' || *sRdString == '\n') {
        sRdString++;
    }
}

static bool IsAlphabetical(char c) {
    return (c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z');
}

static bool IsAlphaNumeric(char c) {
    return IsAlphabetical(c) || (c >= '0' && c <= '9');
}

static bool IsIdentifierBeginning(char c) {
    return IsAlphabetical(c) || (c == '_');
}

static bool IsIdentifierCharacter(char c) {
    return IsAlphaNumeric(c) || (c == '_');
}

static bool ParseOperator(const char* op) {
    size_t opLen = strlen(op);
    if (!strncmp(sRdString, op, opLen)) {
        sRdString += opLen;
        ParseWhitespace();
        return true;
    }
    return false;
}

static s64 ParseNumeric() {
    String numeric = "";
    char* c = sRdString;

    // check for hex
    if (*c == '0' && *(c+1) == 'x') {
        numeric.Add(*c);
        c++;
        numeric.Add(*c);
        c++;
    }

    // continue adding to string
    while (*c >= '0' && *c <= '9') {
        numeric.Add(*c);
        c++;
    }

    // advance parsing
    sRdString = c;
    ParseWhitespace();

    // parse
    return numeric.ParseInt();
}

static s64 ParseFactor() {
    char* c = sRdString;

    // check for unary op
    if (ParseOperator("-")) {
        return -ParseFactor();
    } else if (ParseOperator("+")) {
        return +ParseFactor();
    } else if (ParseOperator("!")) {
        return !ParseFactor();
    } else if (ParseOperator("~")) {
        return ~ParseFactor();
    }

    // check for numeric
    if (*c >= '0' && *c <= '9') {
        return ParseNumeric();
    }

    // check for sub expression
    if (ParseOperator("(")) {
        s64 e1 = ParseExpression();
        if (ParseOperator(")")) {
            return e1;
        } else {
            sRdError = true;
            return 0;
        }
    }

    // check for known identifier
    if (IsIdentifierBeginning(*c)) {
        String identifier = "";
        char* cTmp = c;
        while (IsIdentifierCharacter(*cTmp)) {
            identifier.Add(*cTmp);
            cTmp++;
        }

        // TODO: this was made so that recursive descent can parse the constants...
        // but RD should really use any function pointer passed to it
        bool constantFound = false;
        s64 constantValue = DynOS_Lvl_ParseLevelScriptConstants(identifier, &constantFound);
        if (constantFound) {
            sRdString = cTmp;
            return constantValue;
        }
    }

    sRdError = true;
    return 0;
}

static s64 ParseTerm() {
    s64 f1 = ParseFactor();

    if (ParseOperator("*")) {
        return f1 * ParseFactor();
    } else if (ParseOperator("/")) {
        return f1 / ParseFactor();
    } else if (ParseOperator("%")) {
        return f1 % ParseFactor();
    }

    return f1;
}

static s64 ParseAddSubExpression() {
    s64 t1 = ParseTerm();

    if (ParseOperator("+")) {
        return t1 + ParseTerm();
    } else if (ParseOperator("-")) {
        return t1 - ParseTerm();
    }

    return t1;
}

static s64 ParseShiftExpression() {
    s64 e1 = ParseAddSubExpression();

    if (ParseOperator("<<")) {
        return e1 << ParseAddSubExpression();
    } else if (ParseOperator(">>")) {
        return e1 >> ParseAddSubExpression();
    }

    return e1;
}

static s64 ParseBitAndExpression() {
    s64 e1 = ParseShiftExpression();

    if (ParseOperator("&")) {
        return e1 & ParseShiftExpression();
    }

    return e1;
}

static s64 ParseBitXorExpression() {
    s64 e1 = ParseBitAndExpression();

    if (ParseOperator("^")) {
        return e1 ^ ParseBitAndExpression();
    }

    return e1;
}

static s64 ParseBitOrExpression() {
    s64 e1 = ParseBitXorExpression();

    if (ParseOperator("|")) {
        return e1 | ParseBitXorExpression();
    }

    return e1;
}

static s64 ParseExpression() {
    return ParseBitOrExpression();
}

s64 DynOS_RecursiveDescent_Parse(const char* expr, bool* success) {
    sRdString = (char*)expr;
    sRdError = false;
    s64 value = ParseExpression();
    sRdString = NULL;
    *success = !sRdError;
    //Print(">>> PARSING %s == %d :: %u", expr, value, *success);
    return value;
}