/*************/
/*GEMWIRE    */
/*    ERYTHRO*/
/*************/

#pragma once
#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>
#include <string.h>

/*
 * ARithmetic tokens are prefixed AR.
 * LIteral tokens are prefixed LI.
 * KeyWords are prefixed KW.
 * TYpes are prefixed TY.
 * CoMParisons are prefixed CMP.
 * 
 * 
 * NOTE: Tokens are different from Syntax Operations!
 * 
 * Tokens should represent the characters that invoke them,
 *  not the actions they perform.
 *  
 */


enum TokenTypes {
    LI_EOF,

    AR_PLUS,        // Arithmetic +
    AR_MINUS,       // Arithmetic -
    AR_STAR,        // Arithmetic *
    AR_SLASH,       // Arithmetic /

    CMP_EQUAL,      // =?
    CMP_INEQ,       // !=
    CMP_LT,         // <
    CMP_GT,         // >
    CMP_LTE,        // <=
    CMP_GTE,        // =>

    LI_EQUAL,       // =
    LI_INT,         // Integer literal
    LI_SEMIC,       // ;

    LI_LBRAC,       // {
    LI_RBRAC,       // }

    LI_LPARE,       // (
    LI_RPARE,       // )

    LI_AMP,         // &

    TY_IDENTIFIER,  // Identifier name. Variable, function, etc.
    TY_NONE,        // No return type. Literal void.
    TY_CHAR,        // "char" type keyword
    TY_INT,         // "int" type keyword
    TY_LONG,        // "long" type keyword
    TY_VOID,        // "void" type keyword

    KW_FUNC,        // :: function name incoming
    
    KW_PRINT,
    KW_IF,
    KW_ELSE,
    KW_WHILE,
    KW_FOR,
    KW_RETURN
};

/*
 * All Syntax Operations are prefixed OP.
 *  Terminal Operations are prefixed TERM.
 *  L-Values are prefixed LV.
 *  Reference Operations are prefixed REF.
 *
 * These represent the actions that a token will perform.
 * These are used exclusively in AST construction.
 * 
 * It is important that Tokens and Operations are logically separated,
 *  but that the Operation's index is the same as the Token that invokes it.
 */

enum SyntaxOps {
    OP_ADD = 1,         // Add two numbers.
    OP_SUBTRACT,        // Subtract two numbers.
    OP_MULTIPLY,        // Multiply two numbers.
    OP_DIVIDE,          // Divide two numbers.

    OP_EQUAL,           // Compare equality
    OP_INEQ,            // Compare inequality
    OP_LESS,            // Less than?
    OP_GREAT,           // Greater than?
    OP_LESSE,           // Less than or Equal to?
    OP_GREATE,          // Greater than or Equal to?

    OP_ASSIGN,          // Assign an l-value

    OP_ADDRESS,         // Fetch the address of a var
    OP_DEREF,           // Get the value of the address in a pointer

    TERM_INTLITERAL,    // Integer Literal. This is a virtual operation, so it's a terminal.

    REF_IDENT,          // Reference (read) an identifier (variable).
    LV_IDENT,           // Write an identifier in the form of an l-value.

    OP_WIDEN,           // Something contains a type that needs to be casted up

    OP_CALL,            // Call a function
    OP_RET,             // Return from a function

    OP_COMP,            // Compound statements need a way to be "glued" together. This is one of those mechanisms
    OP_IF,              // If statement
    OP_LOOP,            // FOR, WHILE
    OP_PRINT,           // Print statement

    OP_FUNC,            // Define a function
};


// A node in a Binary Tree that forms the syntax of Erythro
struct ASTNode {
    int Operation;
    int ExprType;       // Value->IntValue's DataType
    struct ASTNode* Left;
    struct ASTNode* Middle;
    struct ASTNode* Right;
    union {
        int IntValue; // TERM_INTLIT's Value
        int ID;       // LV_IDENT's Symbols[] index.
    } Value;
};

struct Token {
    int type;
    int value;
};

/*
 * The Symbol Table, used for variables, functions and
 *  assorted goodies.
 */

struct SymbolTable {
    char* Name;
    int Type;       // An entry in DataTypes, referring to the type of this data
    int Structure;  // An entry in StructureType - metadata on how to process the data
    int EndLabel;   // The number of the label to jump to, in order to exit this function (if applicable)
};


/*
 * The primitive data types for the language
 * //TODO: Move back into TokenTypes
 */
enum DataTypes {
    RET_NONE,       // No return type. Literal void.
    RET_CHAR,       // "char" type keyword
    RET_INT,        // "int" type keyword
    RET_LONG,       // "long" type keyword
    RET_VOID,       // "void" type keyword

                    // Pointer types
    PTR_CHAR,
    PTR_INT,
    PTR_LONG,
    PTR_VOID,       

};

/*
 * The type of the structure of data being examined
 * //TODO: move into TokenTypes?
 */

enum StructureType {
    ST_VAR,         // This is variable
    ST_FUNC         // This is a function
                    // This is an enum
                    // This is a struct
                    // This is a typedef
};

/* * * * * * * * * * * * * * * * * * * * * * * * * * * *
 * * * * * * * * *    L E X I N G      * * * * * * * * *
 * * * * * * * * * * * * * * * * * * * * * * * * * * * */


int Tokenise(struct Token* Token);

int TypesCompatible(int* Left, int* Right, int STRICT);

void VerifyToken(int Type, char* TokenExpected);
void RejectToken(struct Token* Token);

static int ReadIdentifier(int Char, char* Buffer, int Limit);
static int ReadKeyword(char* Str);


/* * * * * * * * * * * * * * * * * * * * * * * * * * * *
 * * * * * *    S Y N T A X      T R E E     * * * * * *
 * * * * * * * * * * * * * * * * * * * * * * * * * * * */


struct ASTNode* ConstructASTNode(int Operation, int Type,
                                 struct ASTNode* Left,
                                 struct ASTNode* Middle,
                                 struct ASTNode* Right,
                                 int IntValue);

struct ASTNode* ConstructASTLeaf(int Operation, int Type, int IntValue);

struct ASTNode* ConstructASTBranch(int Operation, int Type, struct ASTNode* Left, int IntValue);


/* * * * * * * * * * * * * * * * * * * * * * * * * * * *
 * * * * * * * * *    P A R S I N G    * * * * * * * * *
 * * * * * * * * * * * * * * * * * * * * * * * * * * * */

//struct ASTNode* ParseNewASTNode(void);
//struct ASTNode* ParseAdditiveASTNode(void);
struct ASTNode* ParsePrecedenceASTNode(int PreviousTokenPrecedence);

int ParseAST(struct ASTNode* Node);

struct ASTNode* ParsePrimary(void);
//void ParseStatements(void);
struct ASTNode* ParseStatement(void);
struct ASTNode* PrefixStatement();

struct ASTNode* ParseFunction();
struct ASTNode* ParseCompound();


struct ASTNode* CallFunction();
struct ASTNode* ReturnStatement();

int ParsePointer();
int ValueAt(int Type);
int PointerTo(int Type);


int ParseTokenToOperation(int Token);

struct ASTNode* PrintStatement(void);



/* * * * * * * * * * * * * * * * * * * * * * * * * * * *
 * * * * * *  S Y M B O L       T A B L E    * * * * * *
 * * * * * * * * * * * * * * * * * * * * * * * * * * * */

int FindSymbol(char* Symbol);

int AddSymbol(char* Name, int Type, int Structure);

int AddFunctionSymbol(char* Name, int Type, int Structure, int EndLabel);



/* * * * * * * * * * * * * * * * * * * * * * * * * * * *
 * * * *    C O N T R O L       S T A T U S      * * * *
 * * * * * * * * * * * * * * * * * * * * * * * * * * * */

void Die(char* Error);

void DieMessage(char* Error, char* Reason);

void DieDecimal(char* Error, int Number);

void DieChar(char* Error, int Char);


/* * * * * * * * * * * * * * * * * * * * * * * * * * * *
 * * * *     C O D E     G E N E R A T I O N     * * * *
 * * * * * * * * * * * * * * * * * * * * * * * * * * * */

int AssembleTree(struct ASTNode* Node, int Register, int ParentOp);

void DeallocateAllRegisters();

int RetrieveRegister();

void DeallocateRegister(int Register);

int PrimitiveSize(int Type);

int AsLoad(int Value);
int AsAdd(int Left, int Right);
int AsMul(int Left, int Right);
int AsSub(int Left, int Right);
int AsDiv(int Left, int Right);

int AsLdVar(int ID);
int AsStrVar(int Register, int ID);

int AsDeref(int Reg, int Type);
int AsAddr(int ID);

void AsNewSymb(int ID);

int AsEqual(int Left, int Right);
int AsIneq(int Left, int Right);
int AsLess(int Left, int Right);
int AsGreat(int Left, int Right);
int AsLessE(int Left, int Right);
int AsGreatE(int Left, int Right);

int AsCompareJmp(int Operation, int RegisterLeft, int RegisterRight, int Label);
int AsCompare(int Operation, int RegisterLeft, int RegisterRight);
int AsIf(struct ASTNode* Node);
int NewLabel(void);

void AsJmp(int Label);
void AsLabel(int Label);

int AsReturn(int Register, int FuncID);
int AsCall(int Register, int FuncID);

int AsWhile(struct ASTNode* Node);

void AssemblerPrint(int Register);

void AssemblerPreamble();
void AsFunctionPreamble(int ID);
void AsFunctionEpilogue(int ID);


/* * * * * * * * * * * * * * * * * * * * * * *
 * * * *     D E C L A R A T I O N     * * * *
 * * * * * * * * * * * * * * * * * * * * * * */

void BeginVariableDeclaration(void);
struct ASTNode* ParseIdentifier(void);

struct ASTNode* IfStatement();
struct ASTNode* WhileStatement();
struct ASTNode* ForStatement();