#include <assert.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "type.h"

void type_dump_func(struct type *t, FILE *fp)
{
	struct tfield *arg;

	type_dump(t->func.type, fp);
	fputs(" (*)(", fp);

	if (!t->func.args) {
		fputs("void)", fp);
		return;
	}

	for (arg = t->func.args; arg->type != T_VOID; arg++) {
		if (arg != t->func.args)
			fputs(", ", fp);

		type_dump(arg->type, fp);
	}

	fputc(')', fp);
}

void type_dump(struct type *t, FILE *fp)
{
	if (!t) {
		fputs("<NONE>", fp);
		return;
	}

	switch (t->ttype){
	case T_VOID:
		fputs("void", fp);
		break;
	case T_TYPEDEF:
		fputs(t->tdef.name, fp);
		break;
	case T_SCALAR:
		fputs(t->scalar.name, fp);
		break;
	case T_POINTER:
		type_dump(t->ptr.type, fp);
		fputs(" *", fp);
		break;
	case T_ARRAY:
		type_dump(t->array.type, fp);
		fprintf(fp, "[%zu]", t->array.len);
		break;
	case T_STRUCT:
		fputs("struct ", fp);
		fputs(t->sou.name, fp);
		break;
	/* case T_UNION: */
	/* 	fputs("union ", fp); */
	/* 	fputs(t->sou.name, fp); */
	/* 	break; */
	case T_FUNC:
		type_dump_func(t, fp);
		break;
	case T_MAP:
		fputs("map [", fp);
		type_dump(t->map.ktype, fp);
		fputs("] ", fp);
		type_dump(t->map.vtype, fp);
		break;
	}
}

void type_dump_cdecl_sou(struct type *t, FILE *fp)
{
	struct tfield *f;

	type_dump(t, fp);
	fputs(" {\n", fp);
	for (f = t->sou.fields; f->type; f++) {
		fputc('\t', fp);
		type_dump(f->type, fp);
		fprintf(fp, " %s;\n", f->name);
	}
	fputs("}", fp);
}

void type_dump_cdecl(struct type *t, FILE *fp)
{
	switch (t->ttype) {
	case T_TYPEDEF:
		fputs("typedef ", fp);
		type_dump(t->tdef.type, fp);
		fprintf(fp, " %s", t->tdef.name);
		break;

	case T_STRUCT:
	/* case T_UNION: */
		type_dump_cdecl_sou(t, fp);
		break;

	case T_VOID:
	case T_SCALAR:
	case T_POINTER:
	case T_ARRAY:
	case T_MAP:
	case T_FUNC:
		type_dump(t, fp);
		break;
	}
}

/* void types_dump_cdecl(FILE *fp) */
/* { */
/* 	size_t i; */

/* 	for (i = 0; i < types.len; i++) { */
/* 		struct type *t = types.type[i]; */

/* 		type_dump_cdecl(t, stdout); */
/* 		printf(" <sz:0x%zx>\n", t->size); */
/* 	} */
/* } */



struct type *type_normalize(struct type *t)
{
	while (t->ttype == T_TYPEDEF)
		t = t->tdef.type;

	return t;
}

int type_equal(struct type *a, struct type *b)
{
	/* TODO */
	return a == b;
}

int type_compatible(struct type *a, struct type *b)
{

	a = type_normalize(a);
	b = type_normalize(b);

	if (a->ttype != b->ttype)
		return 0;

	switch (a->ttype){
	case T_VOID:
	case T_SCALAR:
	case T_POINTER:
		return 1;
	case T_ARRAY:
		if (a->array.len != b->array.len)
			return 0;

		return type_compatible(a->array.type, b->array.type);
	case T_STRUCT:
	/* case T_UNION: */
		return !strcmp(a->sou.name, b->sou.name);
	case T_FUNC:
		return type_compatible(a->func.type, b->func.type);
	case T_MAP:
		return type_compatible(a->map.vtype, b->map.vtype);

	case T_TYPEDEF:
		assert(0);
	}

	assert(0);
	return 0;
}

static ssize_t type_alignof_struct(struct type *t)
{
	struct tfield *f;
	ssize_t falign, align = -EINVAL;

	tfields_foreach(f, t->sou.fields) {
		falign = type_alignof(f->type);

		if (falign < 0)
			return falign;

		if (falign > align)
			align = falign;
	}

	return align;
}

ssize_t type_alignof(struct type *t)
{
	switch (t->ttype){
	case T_VOID:
	case T_SCALAR:
	case T_POINTER:
	case T_FUNC:
	case T_MAP:
		return type_sizeof(t);
	case T_TYPEDEF:
		return type_alignof(t->tdef.type);
	case T_ARRAY:
		return type_alignof(t->array.type);
	case T_STRUCT:
		return type_alignof_struct(t);
	}

	return -EINVAL;
}

ssize_t type_offset_size_of(struct type *t, const char *field)
{
	struct tfield *f;
	size_t offset = 0;
	ssize_t fsize, falign;

	assert(t->ttype == T_STRUCT);

	if (!t->sou.fields)
		return -ENOENT;

	tfields_foreach(f, t->sou.fields) {
		fsize = type_sizeof(f->type);
		if (fsize < 0)
			return fsize;

		falign = type_alignof(f->type);
		if (falign < 0)
			return falign;

		if (!t->sou.packed && (falign > 1))
			offset += falign - (offset % falign);

		if (field && !strcmp(f->name, field))
			return offset;

		offset += fsize;
	}

	if (field)
		return -ENOENT;

	if (!t->sou.packed && offset && (falign > 1))
		offset += falign - (offset % falign);

	return offset;
	
}

ssize_t type_offsetof(struct type *t, const char *field)
{
	return type_offset_size_of(t, field);
}

ssize_t type_sizeof_struct(struct type *t)
{
	return type_offset_size_of(t, NULL);
}

ssize_t type_sizeof(struct type *t)
{
	switch (t->ttype){
	case T_VOID:
		return sizeof(void);
	case T_SCALAR:
		return t->scalar.size;
	case T_TYPEDEF:
		return type_sizeof(t->tdef.type);
	case T_POINTER:
	case T_FUNC:
		return sizeof(void *);
	case T_ARRAY:
		return t->array.len * type_sizeof(t->array.type);
	case T_STRUCT:
		return type_sizeof_struct(t);
	case T_MAP:
		return sizeof(int);
	}

	return -EINVAL;
}



int all_types_cmp(const void *_a, const void *_b)
{
	const struct type *a = *((struct type **)_a);
	const struct type *b = *((struct type **)_b);

	return a - b;
}

struct type_list {
	struct type **types;
	size_t len;
} all_types;

#define types_foreach(_t) \
	for ((_t) = all_types.types[0]; (_t) <= all_types.types[all_types.len]; (_t)++)

int type_add(struct type *t)
{
	if (bsearch(t, all_types.types, all_types.len,
		    sizeof(*all_types.types), all_types_cmp))
		return 0;

	/* type_size_set(t); */

	all_types.types = realloc(all_types.types,
				  ++all_types.len * sizeof(*all_types.types));
	all_types.types[all_types.len - 1] = t;
	qsort(all_types.types, all_types.len, sizeof(*all_types.types), all_types_cmp);

	return 0;
}

int type_add_list(struct type **ts)
{
	int err;

	for (; *ts; ts++) {
		err = type_add(*ts);
		if (err)
			return err;
	}

	return 0;
}

struct type *type_array_of(struct type *type, size_t len)
{
	struct type *t;

	types_foreach(t) {
		if ((t->ttype == T_ARRAY)
		    && (t->array.type == type)
		    && (t->array.len == len))
			return t;
	}

	t = calloc(1, sizeof(*t));
	t->ttype = T_ARRAY;
	t->array.type = type;
	t->array.len = len;
	type_add(t);
	return t;
}

struct type *type_map_of(struct type *ktype, struct type *vtype)
{
	struct type *t;

	types_foreach(t) {
		if ((t->ttype == T_MAP)
		    && (t->map.ktype == ktype)
		    && (t->map.vtype == vtype))
			return t;
	}

	t = calloc(1, sizeof(*t));
	t->ttype = T_MAP;
	t->map.vtype = vtype;
	t->map.ktype = ktype;
	type_add(t);
	return t;
}

struct type *type_ptr_of(struct type *type)
{
	struct type *t;

	types_foreach(t) {
		if ((t->ttype == T_POINTER)
		    && (t->ptr.type == type))
			return t;
	}

	t = calloc(1, sizeof(*t));
	t->ttype = T_POINTER;
	t->ptr.type = type;
	type_add(t);
	return t;
}

#define is_signed(_t) (((_t)(-1)) < 0)

#define builtin_scalar(_t) {				\
		.ttype = T_SCALAR,			\
		.scalar = {				\
			.name = #_t,			\
			.size = sizeof(_t),		\
			.is_signed = is_signed(_t),	\
		},					\
	}

struct type t_void = { .ttype = T_VOID };

#pragma GCC diagnostic ignored "-Wtype-limits"
/* is_signed will generate a warning for unsigned types since the
 * expression can never be true. this is exactly what we're interested
 * in here though. it gets us out of having to specify scalar
 * signedness per architecture. */

struct type t_char  = builtin_scalar(char);
struct type t_schar = builtin_scalar(signed char);
struct type t_uchar = builtin_scalar(unsigned char);

struct type t_short  = builtin_scalar(short);
struct type t_sshort = builtin_scalar(signed short);
struct type t_ushort = builtin_scalar(unsigned short);

struct type t_int  = builtin_scalar(int);
struct type t_sint = builtin_scalar(signed int);
struct type t_uint = builtin_scalar(unsigned int);

struct type t_long  = builtin_scalar(long);
struct type t_slong = builtin_scalar(signed long);
struct type t_ulong = builtin_scalar(unsigned long);

struct type t_llong  = builtin_scalar(long long);
struct type t_sllong = builtin_scalar(signed long long);
struct type t_ullong = builtin_scalar(unsigned long long);

#pragma GCC diagnostic pop

struct type *builtin_types[] = {
	&t_void,
	&t_char,  &t_schar,  &t_uchar,
	&t_short, &t_sshort, &t_ushort,
	&t_int,   &t_sint,   &t_uint,
	&t_long,  &t_slong,  &t_ulong,
	&t_llong, &t_sllong, &t_ullong,

	NULL
};

__attribute__((constructor))
static void type_init(void)
{
	type_add_list(builtin_types);
}