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

#pragma once

#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>
#include <string.h>
#include <stdbool.h>


/*
 * ARithmetic tokens are prefixed AR.
 * LIteral tokens are prefixed LI.
 * KeyWords are prefixed KW.
 * TYpes are prefixed TY.
 * CoMParisons are prefixed CMP.
 * BOOLean maths is prefixed BOOL.
 * BITwise maths is prefixed BIT.
 * Arithmetic SHifts are prefixed SH.
 * PlusPlusMinusMinus operators are prefixed PPMM.
 * 
 * 
 * NOTE: Tokens are different from Syntax Operations!
 * 
 * Tokens should represent the characters that invoke them,
 *  not the actions they perform.
 *  
 */


enum TokenTypes {
    LI_EOF,
    LI_EQUAL,       // =

    BOOL_OR,        // Boolean OR (||)
    BOOL_AND,       // Boolean AND (&&)

    BIT_OR,         // Bitwise OR (|)
    BIT_XOR,        // Bitwise XOR (^)
    BIT_AND,        // Bitwise AND (&)

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

    SH_LEFT,        // Left Shift (<<)
    SH_RIGHT,       // Right Shift (>>)

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

    PPMM_PLUS,      // PPMM Increment (++)
    PPMM_MINUS,     // PPMM Decrement (--)

    BOOL_INVERT,    // Boolean Invert (!)

    BIT_NOT,        // Bitwise NOT (~)

    LI_INT,         // Integer literal
    LI_STR,         // String literal
    LI_SEMIC,       // ;
    LI_COLON,       // :

    LI_LBRAC,       // {
    LI_RBRAC,       // }

    LI_LBRAS,       // [
    LI_RBRAS,       // ]

    LI_LPARE,       // (
    LI_RPARE,       // )

    LI_COM,         // ,
    LI_DOT,         // .
    LI_ARROW,       // ->

    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_BREAK,       // "break" keyword
    KW_CONTINUE,    // "continue" keyword

    KW_SWITCH,      // "switch" keyword
    KW_DEFAULT,     // "default" keyword
    KW_CASE,        // "case" keyword

    KW_PRINT,
    KW_IF,
    KW_ELSE,
    KW_WHILE,
    KW_FOR,
    KW_RETURN,
    KW_STRUCT,
    KW_UNION,
    KW_ENUM,
    KW_ALIAS,
    
    KW_IMPORT
};

/*
 * 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.
 *
 * Every five elements, an index is assigned. These are the natural indices.
 * They are marked to make navigation of the Syntax Tree easier.
 */

enum SyntaxOps {
    OP_ASSIGN = 1,      // Assign an l-value

    OP_BOOLOR,          // Boolean OR two statements
    OP_BOOLAND,         // Boolean AND two statements
    OP_BITOR,           // Bitwise OR a number
    OP_BITXOR = 5,      // Bitwise XOR a number
    OP_BITAND,          // Bitwise AND a number

    OP_EQUAL,           // Compare equality
    OP_INEQ,            // Compare inequality
    OP_LESS,            // Less than?
    OP_GREAT = 10,      // Greater than?
    OP_LESSE,           // Less than or Equal to?
    OP_GREATE,          // Greater than or Equal to?

    OP_SHIFTL,          // Arithmetic Shift Left (Multiply by 2)
    OP_SHIFTR,          // Arithmetic Shift Right (Divide by 2)

    OP_ADD = 15,        // Add two numbers.
    OP_SUBTRACT,        // Subtract two numbers.
    OP_MULTIPLY,        // Multiply two numbers.
    OP_DIVIDE,          // Divide two numbers.

    OP_PREINC,          // Increment var before reference.
    OP_PREDEC = 20,     // Decrement var before reference.
    OP_POSTINC,         // Increment var after reference.
    OP_POSTDEC,         // Decrement var after reference.

    OP_BITNOT,          // Invert a number bitwise
    OP_BOOLNOT,         // Invert a statement logically
    OP_NEGATE = 25,     // Negate a number (turn a positive number negative)

    OP_BOOLCONV,        // Convert an expression to a boolean.s

    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.
    TERM_STRLITERAL = 30, // String Literal. Also terminal.

    REF_IDENT,          // Reference (read) an identifier (variable).

    OP_WIDEN,           // Something contains a type that needs to be casted up
    OP_SCALE,           // We have a pointer that needs to be scaled!

    OP_CALL,            // Call a function
    OP_RET = 35,        // 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 = 40,       // Define a function
    OP_BREAK,           // Break out of the loop
    OP_CONTINUE,        // Continue the loop

    OP_SWITCH,          // Switch statement
    OP_DEFAULT,         // Default case
    OP_CASE = 45        // Case
};


/**
 * The way syntax is stored by the parser and assembled into a usable file.
 * An ASTNode forms an item in a linked list.
 *
 * Thus, you can traverse up and down a tree of ASTNodes easily.
 *
 * Walking the tree is as simple as reading the Operation and recursively reading the Left, Middle and Right nodes as called for.
 * For example, an if-else statement uses all three subnodes.
 * 
 * This means that AST Nodes aren't exactly a binary tree, but a syntax tree nonetheless.
 */
struct ASTNode {
    int Operation;      // SyntaxOps Index
    int ExprType;       // Value->IntValue's DataType
    int RVal;           // True if this node is an Rval, false if Lval
    struct ASTNode* Left;
    struct ASTNode* Middle;
    struct ASTNode* Right;
    struct SymbolTableEntry* Symbol;
    union {
        int Size;     // OP_SCALE's linear representation
        int IntValue; // TERM_INTLIT's Value
    };
};

/**
 * Describes the basic unit of syntax in the language.
 * A token has a type (an index into the TokenTypes enum) and a value.
 *
 * The value represents the numerical value of an integer literal, etc.
 */
struct Token {
    int type;
    int value;
};

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

struct SymbolTableEntry {
    char* Name;
    int Type;       // An entry in DataTypes, referring to the type of this data
    struct SymbolTableEntry* CompositeType; // A pointer to the start of a Symbol Table list that represents a certain Composite type
    int Structure;  // An entry in StructureType - metadata on how to process the data
    int Storage;    // The scope of this symbol - decides when it is discarded.
    int Length;     // Size of an array, or the number of parameters in a function
    int Size;       // Total size in bytes.

    int* InitialValues;

    int IntValue;   // For an enum - The value of an Enum entry

    union {
        int EndLabel;   // For a function - The number of the label to jump to, in order to exit this function (if applicable)
        int SinkOffset; // For a variable - How many times must we sink the rbp to get to this symbol in the stack?
    };

    struct SymbolTableEntry* NextSymbol; // The next symbol in a list
    struct SymbolTableEntry* Start; // The first member in a list
};


/**
 * Information about a given source file.
 *
 * A file that starts the parsing of another file will never confuse the parser.
 *
 * It is the end goal that the parser will be multithreaded, operating on a single file at a time.
 * 
 * Note that files do not contain their own symbol tables - these are global.
 */
struct FileData {
    // Whether or not this file will accept definitions of functions.
    bool AllowDefinitions;

    // A FILE stream that we can read the file from.
    FILE* Stream;

    // The filename of the source code
    char* SourceName;
    // The filename of the assembly output
    char* AssemblyName;
    // The filename of the assembled object code
    char* ObjectName;

    // The line of the file we are currently working on, -1 if it is finished
    long CurrentLine;
    // The column of the file we are currently working on, -1 if it is finished
    long CurrentColumn;
    // The depth of the loop currently being parsed.
    long CurrentLoopDepth;
    // The column that was last marked as "valid", the start of the error block if something goes wrong.
    long CurrentSafeColumn;

    // Whether or not we are currently parsing a switch statement - changes the behavior of compound statements!
    bool SwitchStatement;

    // The symbol currently being lexed - TokenTypes index and integer value.
    struct Token CurrentSymbol;
    // The function currently being parsed - null if in global scope or if finished.
    struct SymbolTableEntry* FunctionEntry;

    // Once ready, the full AST trees of this file.
    struct ASTNode* Tree;
};


enum StorageScope {
    SC_GLOBAL = 1,  // Global Scope
    SC_STRUCT,      // Struct Definitions
    SC_UNION,       // Union Definitions
    SC_ENUM,        // Enum Definitions
    SC_ENUMENTRY,   // Enum Entry Names
    SC_ALIAS,       // Typedef aliases
    SC_MEMBER,      // The members of Structs or Unions
    //SC_CLASS,       // Class-local definitions
    //SC_STATIC,      // Static storage definitions
    SC_PARAM,       // Function parameters
    SC_LOCAL        // Function-local scope.
    //  There is no deeper scope than function.
};


/*
 * The types of data being held in memory.
 * The lowest 4 bits of these enum values
 *  encode a nested pointer type.
 *
 * This meaning, a single enum can hold
 *  ****************int types.
 * Should be enough for everyone, right?
 */
enum DataTypes {
    RET_NONE,            // No return type. Literal void.
    RET_CHAR = 16,       // "char" type keyword
    RET_INT = 32,        // "int" type keyword
    RET_LONG = 48,       // "long" type keyword
    RET_VOID = 64,       // "void" type keyword

    DAT_STRUCT = 80,     // Struct Data
    DAT_UNION,           // Union Data
    DAT_ENUM,            // Enum Data
    DAT_ALIAS,           // Alias Definition
    DAT_NONE,            // No type, no work needed.
};

/*
 * 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
    ST_ARR,         // This is an array
    ST_RUCT,        // This is a struct
    ST_ENUM,        // This is an enum
    // This is a typedef
};


/* * * * * * * * * * * * * * * * * * * * * * * * * * * *
 * * * * * * *      A R G U M E N T S      * * * * * * *
 * * * * * * * * * * * * * * * * * * * * * * * * * * * */

char* Suffixate(char* String, char Suffix);

void Compile(struct FileData* InputFile);

void Assemble(struct FileData* InputFile);

void Link(char* Output, struct FileData* Objects[], int ObjectsLength);

void DisplayUsage(char* ProgName);


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

void Tokenise();

void VerifyToken(int Type, char* TokenExpected);
bool OptionallyConsume(int Type);

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

static int ReadKeyword(char* Str);

void ImportModule();

/* * * * * * * * * * * * * * * * * * * *
 * * * * *     T Y P E S     * * * * * *
 * * * * * * * * * * * * * * * * * * * */

struct ASTNode* MutateType(struct ASTNode* Tree, int RightType, int Operation);

int TypeIsInt(int Type);

int TypeIsPtr(int Type);

char* TypeNames(int Type);

int TypeSize(int Type, struct SymbolTableEntry* Composite);


/* * * * * * * * * * * * * * * * * * * * * * * * * * * *
 * * * * * *    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,
                                 struct SymbolTableEntry* Symbol,
                                 int IntValue);

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

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


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

struct ASTNode* ParsePrecedenceASTNode(int PreviousTokenPrecedence);


struct ASTNode* ParsePrimary(void);

struct ASTNode* ParseStatement(void);

struct ASTNode* PrefixStatement();

struct ASTNode* PostfixStatement();

void ParseGlobals();

int ParseDeclarationList(struct SymbolTableEntry** CompositeType, int ClassType, int StatementEndSymbool, int TerminateSymbol, struct ASTNode** Tree);

struct ASTNode* ParseCompound();

struct SymbolTableEntry* BeginCompositeDeclaration(int Type);

struct ASTNode* ParseExpressionList(int terminateToken);

struct ASTNode* CallFunction();

struct ASTNode* ReturnStatement();

struct ASTNode* BreakStatement();

struct ASTNode* ContinueStatement();

int ValueAt(int Type);

int PointerTo(int Type);

struct ASTNode* AccessArray();

struct ASTNode* AccessMember(bool Deref);

int ParseTokenToOperation(int Token);

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

void DumpAllLists();

void DumpList(struct SymbolTableEntry* List);

struct SymbolTableEntry* FindSymbol(char* Symbol);

struct SymbolTableEntry* FindLocal(char* Symbol);

struct SymbolTableEntry* FindGlobal(char* Symbol);

struct SymbolTableEntry* FindStruct(char* Symbol);

struct SymbolTableEntry* FindAlias(char* Symbol);

struct SymbolTableEntry* FindEnum(char* Symbol);

struct SymbolTableEntry* FindEnumMember(char* Symbol);

struct SymbolTableEntry* FindUnion(char* Symbol);

struct SymbolTableEntry* FindMember(char* Symbol);

void AppendSymbol(struct SymbolTableEntry** Head, struct SymbolTableEntry** Tail, struct SymbolTableEntry* Node);

void FreeLocals();

void ClearTables();

struct SymbolTableEntry* AddSymbol(char* Name, int Type, int Structure, int Storage, int Length, int SinkOffset,
                                   struct SymbolTableEntry* CompositeType);

/* * * * * * * * * * * * * * * * * * * * * * * * * * * *
 * * * *    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);

void DieBinary(char* Error, int Number);

void ErrorReport(char* message, ...);

void Safe();


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

int PrimitiveSize (int);

/**
 * All of the functions required to be implemented by an Assembler Module.
 */
struct AssemblerVtable {
    // Entry Point
    int (*AssembleTree)(struct ASTNode*, int, int, int, int);
    // Register management
    void (*DeallocateAllRegisters)();
    int (*RetrieveRegister)();
    void (*DeallocateRegister)(int);
    // Alignment
    int (*AsAlignMemory)(int, int, int);
    int (*AsCalcOffset)(int);
    void (*AsNewStackFrame)();
    // Basic operations
    int (*AsLoad)(int);
    int (*AsAdd)(int, int);
    int (*AsMul)(int, int);
    int (*AsSub)(int, int);
    int (*AsDiv)(int, int);
    int (*AsLdGlobalVar)(struct SymbolTableEntry*, int);
    int (*AsLdLocalVar)(struct SymbolTableEntry*, int);
    int (*AsStrGlobalVar)(struct SymbolTableEntry*, int);
    int (*AsStrLocalVar)(struct SymbolTableEntry*, int);
    int (*AsDeref)(int, int);
    int (*AsStrDeref)(int, int, int);
    int (*AsAddr)(struct SymbolTableEntry*);
    int (*AsNewString)(char*);
    int (*AsLoadString)(int);

    // Comparisons
    int (*AsEqual)(int, int);
    int (*AsIneq)(int, int);
    int (*AsLess)(int, int);
    int (*AsGreat)(int, int);
    int (*AsLessE)(int, int);
    int (*AsGreatE)(int, int);

    // Binary operations
    int (*AsBitwiseAND)(int, int);
    int (*AsBitwiseOR)(int, int);
    int (*AsBitwiseXOR)(int, int);
    int (*AsNegate)(int);
    int (*AsInvert)(int);
    int (*AsBooleanNOT)(int);
    int (*AsShiftLeft)(int, int);
    int (*AsShiftRight)(int, int);

    // Comparisons
    int (*AsBooleanConvert)(int, int, int);
    int (*AsCompareJmp)(int, int, int, int);
    int (*AsCompare)(int, int, int);

    // Loops and jumps
    int (*AsIf)(struct ASTNode*, int, int);
    int (*AsWhile)(struct ASTNode*);
    int (*AsSwitch)(struct ASTNode*);
    void (*AsSwitchTable)(int, int, int, int*, int*, int);
    int (*NewLabel)();
    void (*AsJmp)(int);
    void (*AsLabel)(int);

    // Call and return
    int (*AsShl)(int, int);
    int (*AsReturn)(struct SymbolTableEntry*, int);
    int (*AsCallWrapper)(struct ASTNode*);
    void (*AsCopyArgs)(int, int);
    int (*AsCall)(struct SymbolTableEntry*, int);
    void (*AssemblerPrint)(int);

    // Preamble and epilogue
    void (*AsGlobalSymbol)(struct SymbolTableEntry*);
    void (*AssemblerPreamble)();
    void (*AsFunctionPreamble)(struct SymbolTableEntry*);
    void (*AsFunctionEpilogue)(struct SymbolTableEntry*);
};

struct AssemblerModule{
    char* name;
    const struct AssemblerVtable* vtable;
};

int RegisterModule(struct AssemblerModule*);

void RegisterAllModules();

// Module List
void RegisterQBE();
void RegisterWin32ASM();
void RegisterLinuxASM();
void RegisterJVM();


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

struct SymbolTableEntry* BeginVariableDeclaration(int Type, struct SymbolTableEntry* Composite, int Scope);

struct ASTNode* IfStatement();

struct ASTNode* WhileStatement();

struct ASTNode* ForStatement();

struct ASTNode* SwitchStatement();


void DumpTree(struct ASTNode* node, int level);