#ifndef CORE_H
#define CORE_H

// cstdlib includes
#include "math.h"
#include "stdbool.h"
#include "stdint.h" // necessary for int type sizes
#include "stdio.h"
#include "time.h" // TODO(djledda): try not to depend on this one

// ### Misc macros ###
#if ENABLE_ASSERT
#define Assert(expression) if (!(expression)) {*(volatile int *)0 = 0;}
#else
#define Assert(expression)
#endif

#define function static
#define global static
#define local_persist static

// ### Types ###
typedef int8_t int8;
typedef int16_t int16;
typedef int32_t int32;
typedef int64_t int64;
typedef uint8_t uint8;
typedef uint16_t uint16;
typedef uint32_t uint32;
typedef uint64_t uint64;
typedef uint8_t byte;
typedef float real32;
typedef double real64;
typedef struct string string;

// ### Sizes and Numbers ###
#define Bytes(n) (n)
#define Kilobytes(n) (n << 10)
#define Megabytes(n) (n << 20)
#define Gigabytes(n) (((uint64)n) << 30)
#define Terabytes(n) (((uint64)n) << 40)

#define Thousand(n) ((n)*1000)
#define Million(n)  ((n)*1000000)
#define Billion(n)  ((n)*1000000000LL)

#define ArrayCount(arr) (sizeof(arr) / sizeof((arr)[0]))
#define MemberSize(type, memberName) sizeof(((type *)0)->memberName)
#define MemberType(type, memberName) typeof(((type *)0)->memberName)
#define MemberSizeUnderlying(type, memberName) sizeof(*((type *)0)->memberName)
#define MemberTypeUnderlying(type, memberName) typeof(*((type *)0)->memberName)

// ### Arenas ###
typedef struct {
    void *memory;
    size_t capacity;
    size_t head;
} Arena;

typedef struct {
    Arena *arena;
    size_t start;
} Scratch;

void *pushSize(Arena *arena, size_t bytes);
void *pushSizeFill(Arena *arena, size_t bytes, byte fill);
Arena *arenaAlloc(size_t capacity);
void arenaFree(Arena *arena);
void arenaFreeFrom(Arena *arena, size_t pos);
void arenaPopTo(Arena *arena, void *pos);

void initialiseDjStdCore();

Scratch scratchStart(Arena **conflicts, size_t conflictCount);
void scratchEnd(Scratch scratch);

#define PushArray(arena, type, size) (type *)pushSize(arena, sizeof(type) * (size))
#define PushArrayZero(arena, type, size) (type *)pushSizeFill(arena, sizeof(type) * (size), 0)
#define PushStruct(arena, type) (type *)pushSize(arena, sizeof(type))
#define PushStructZero(arena, type) (type *)pushSizeFill(arena, sizeof(type), 0)

// ### Vectors ###
typedef union {
    struct {
        real32 x;
        real32 y;
    };
    real32 vec[2];
} Vec2;
inline function Vec2 vec2(real32 x, real32 y) {
    Vec2 result = {0};
    result.x = x;
    result.y = y;
    return result;
}

typedef union {
    struct {
        real32 x;
        real32 y;
        real32 z;
    };
    real32 vec[3];
} Vec3;
inline function Vec3 vec3(real32 x, real32 y, real32 z) {
    Vec3 result = {0};
    result.x = x;
    result.y = y;
    result.z = z;
    return result;
}

typedef union {
    struct {
        real32 r;
        real32 g;
        real32 b;
        real32 a;
    };
    struct {
        real32 x;
        real32 y;
        real32 z;
        real32 w;
    };
    real32 vec[4];
} Vec4;
inline function Vec4 vec4(real32 x, real32 y, real32 z, real32 w) {
    Vec4 result = {0};
    result.x = x;
    result.y = y;
    result.z = z;
    result.w = w;
    return result;
}

// ### Lists ###
#define DefineList(type, prefix) \
    typedef struct {\
        type* data;\
        size_t length;\
        size_t head;\
    } prefix ## List

DefineList(string, String);

#define PushList(arena, type, size) (type){ (MemberTypeUnderlying(type, data) *)pushSize(arena, MemberSizeUnderlying(type, data)*size), size, 0 }
#define EmptyList(type) (type){ NULL, 0, 0 }
#define PushListZero(arena, type, size) (type){ (MemberTypeUnderlying(type, data) *)pushSizeFill(arena, MemberSizeUnderlying(type, data)*size, 0), size, 0 }
#define PushFullList(arena, type, size) (type){ (MemberTypeUnderlying(type, data) *)pushSize(arena, MemberSizeUnderlying(type, data))*size, size, size }
#define PushFullListZero(arena, type, size) (type){ (MemberTypeUnderlying(type, data) *)pushSizeFill(arena, MemberSizeUnderlying(type, data)*size, 0), size, size }
#define ArrayAsList(type, array) (type){ array, ArrayCount(array), ArrayCount(array) }

#define AppendList(list, element) \
    if ((list)->head < (list)->length) { \
        (list)->data[(list)->head++] = (element); \
    }
#define ZeroListFull(list) memset((list)->data, 0, (list)->head * sizeof(T))
#define ZeroList(list) (list)->head = 0; \
    memset((list)->data, 0, (list)->head * sizeof(T));

// ### Strings ###
struct string {
    char *str;
    size_t length;
};
#define STB_SPRINTF_DECORATE(name) stb_##name // define this before including if you want to change the names
#include "vendor/stb_sprintf.h"

#define s(lit) ((string){(char *)(lit), sizeof(lit) - 1})
#define PushString(arena, length) ((string){ (char *)pushSize(arena, length), (length) })
#define PushStringFill(arena, length, characterByte) ((string){ (char *)pushSizeFill(arena, length, characterByte), (length) })

// C Strings
DefineList(char, Char);
const char *cstringFromCharList(Arena *arena, CharList buf);
const char *cstring(Arena *arena, string str);
size_t calcStringLen(const char *str);
string strFromCString(Arena *arena, const char *str);

bool strEql(string s1, string s2);
bool strStartsWith(string str, string testStr);
bool stringContains(string str, char c);

string strReverse(Arena *arena, string str);
string strSlice(string str, size_t start, size_t stop);
string strSliceCStr(char *data, size_t start, size_t stop);
StringList strSplit(Arena *arena, string splitStr, string inputStr);
string strPrintfv(Arena *arena, const char *fmt, va_list args);
string strPrintf(Arena *arena, const char *fmt, ...);

typedef struct { uint8 result; bool valid; } ParsePositiveIntResult;
ParsePositiveIntResult parsePositiveInt(string str, size_t *lengthPointer);
typedef struct { real32 result; bool valid; } ParsePositiveReal32Result;
ParsePositiveReal32Result parsePositiveReal32(string str, size_t *lengthPointer);

inline function bool isNumeric(char c);

// ### Cmdline ###
StringList getArgs(Arena *arena, int argc, char **argv);

// ### Time ###
typedef uint64 UnixTimestamp;
typedef struct tm Timestamp;

UnixTimestamp getSystemUnixTime();
Timestamp timestampFromUnixTime(UnixTimestamp *unixTimestamp);
string formatTimeHmsUnix(Arena *arena, UnixTimestamp time);
string formatTimeHms(Arena *arena, Timestamp *time);
string formatTimeYmdUnix(Arena *arena, UnixTimestamp time);
string formatTimeYmd(Arena *arena, Timestamp *time);

// ### Linked Lists ###
// TODO(djledda): implement basic linked lists (based on arenas?)

// ### Logging ###
typedef enum {
    StdStream_stdout,
    StdStream_stdin,
    StdStream_stderr,
} StdStream;

#define ANSI_INSTRUCTION_FROM_ENUM(ansiCodeEnum) ANSI_INSTRUCTION(ansiCodeEnum)
#define ANSI_INSTRUCTION(ansiCode) "\u001b[" #ansiCode "m"
#define ANSI_INSTRUCTION_STR(ansiCodeStr) "\u001b[" ansiCodeStr "m"
#define ANSI_RESET ANSI_INSTRUCTION(0)

#define ANSI_fg_black 30
#define ANSI_fg_red 31
#define ANSI_fg_green 32
#define ANSI_fg_yellow 33
#define ANSI_fg_blue 34
#define ANSI_fg_magenta 35
#define ANSI_fg_cyan 36
#define ANSI_fg_white 37

#define ANSI_fg_bblack 90
#define ANSI_fg_bred 91
#define ANSI_fg_bgreen 92
#define ANSI_fg_byellow 93
#define ANSI_fg_bblue 94
#define ANSI_fg_bmagenta 95
#define ANSI_fg_bcyan 96
#define ANSI_fg_bwhite 97

#define ANSI_bg_black 40
#define ANSI_bg_red 41
#define ANSI_bg_green 42
#define ANSI_bg_yellow 43
#define ANSI_bg_blue 44
#define ANSI_bg_magenta 45
#define ANSI_bg_cyan 46
#define ANSI_bg_white 47

#define ANSI_bg_bblack 100
#define ANSI_bg_bred 101
#define ANSI_bg_bgreen 102
#define ANSI_bg_byellow 103
#define ANSI_bg_bblue 104
#define ANSI_bg_bmagenta 105
#define ANSI_bg_bcyan 106
#define ANSI_bg_bwhite 107

#define COLOR_TEXT(text, foregroundcolor) ANSI_INSTRUCTION_FROM_ENUM(foregroundcolor) text ANSI_RESET
#define COLOR_TEXT_BG(text, backgroundcolor) ANSI_INSTRUCTION_FROM_ENUM(backgroundcolor) text ANSI_RESET
#define COLOR_TEXT_FG_BG(text, foregroundcolor, backgroundcolor) ANSI_INSTRUCTION_FROM_ENUM(foregroundcolor) ANSI_INSTRUCTION_FROM_ENUM(backgroundcolor) text  ANSI_RESET
#define COLOR_TEXT_RGB(text, red, green, blue) ANSI_INSTRUCTION_STR("38;2;" #red ";" #green ";" #blue) text ANSI_RESET

DefineList(int, Int);
void printIntList(IntList l);
void printStrList(StringList l);
extern void (*print)(const char *fmt, ...);

// ### Loops ###
#define EachIn(list, it) size_t it = 0; it < (list).head; it++
#define EachInReversed(list, it) size_t it = (list).head - 1; it >= 0 && it < (list).head; it--
#define EachInArray(arr, it)  size_t it = 0; it < ArrayCount(arr); ++it

// ### Misc ###
int intCompare(const void *a, const void *b);

#endif