#include <stdio.h>
#include <stdarg.h>
#include <stdbool.h>
#include <string.h>
#include <assert.h>

#include <gc.h>

#include "../../../include/oberon.h"
#include "../../oberon-internals.h"
#include "generator-jvm.h"

char *
new_string(const char * format, ...)
{
	va_list ptr;
	va_start(ptr, format);

	char buf[1024];
	vsnprintf(buf, 1024, format, ptr);

	va_end(ptr);

	char * result;
	int size;

	size = strlen(buf);
	result = GC_MALLOC(size + 1);
	memset(result, 0, size);
	strncpy(result, buf, size);

	return result;
}

void
oberon_generator_init_context(oberon_context_t * ctx)
{
	gen_context_t * gen_context = GC_MALLOC(sizeof *gen_context);
	memset(gen_context, 0, sizeof *gen_context);

	ctx -> gen_context = gen_context;
}

void
oberon_generator_destroy_context(oberon_context_t * ctx)
{
	ctx -> gen_context = NULL;
}

static char * get_class_full_name(oberon_context_t * ctx, oberon_type_t * type);

static char *
get_descriptor(oberon_context_t * ctx, oberon_type_t * type)
{
	char * desc;

	switch(type -> class)
	{
		case OBERON_TYPE_VOID:
			return new_string("V");
			break;
		case OBERON_TYPE_INTEGER:
			switch(type -> size)
			{
				case 1:
					return new_string("B");
					break;
				case 2:
					return new_string("S");
					break;
				case 4:
					return new_string("I");
					break;
				case 8:
					return new_string("J");
					break;
				default:
					oberon_error(ctx, "get_descriptor: unsupported int size %i", type -> size);
					break;
			}
			break;
		case OBERON_TYPE_REAL:
			switch(type -> size)
			{
				case 4:
					return new_string("F");
					break;
				case 8:
					return new_string("D");
					break;
				default:
					oberon_error(ctx, "get_descriptor: unsupported float size %i", type -> size);
					break;
			}
			break;
		case OBERON_TYPE_BOOLEAN:
			return new_string("Z");
			break;
		case OBERON_TYPE_PROCEDURE:
		case OBERON_TYPE_RECORD:
			desc = get_class_full_name(ctx, type);
			return new_string("L%s;", desc);
			break;
		case OBERON_TYPE_ARRAY:
			desc = get_descriptor(ctx, type -> base);
			return new_string("[%s", desc);
			break;
		default:
			oberon_error(ctx, "print_descriptor: unsupported type class %i", type -> class);
			break;
	}

	return NULL;
}

static char
get_prefix(oberon_context_t * ctx, oberon_type_t * type)
{
	int size = type -> size;
	switch(type -> class)
	{
		case OBERON_TYPE_BOOLEAN:
		case OBERON_TYPE_INTEGER:
			return (size <= 4) ? ('i') : ('l');
			break;
		case OBERON_TYPE_PROCEDURE:
		case OBERON_TYPE_ARRAY:
		case OBERON_TYPE_RECORD:
		case OBERON_TYPE_POINTER:
			return 'a';
			break;
		case OBERON_TYPE_REAL:
			return (size <= 4) ? ('f') : ('d');
			break;
	}

	oberon_error(ctx, "get_prefix: wat");
	return '!';
}

static char *
get_field_full_name(oberon_context_t * ctx, oberon_object_t * x)
{
	return new_string("%s/%s", x -> module -> name, x -> name);
}

static char *
get_class_full_name(oberon_context_t * ctx, oberon_type_t * type)
{
	int rec_id;
	char * name = NULL;

	switch(type -> class)
	{
		case OBERON_TYPE_PROCEDURE:
			name = new_string("SYSTEM$PROCEDURE");

			char * desc;
			desc = get_descriptor(ctx, type -> base);
			name = new_string("%s$%s", name, desc);

			int num = type -> num_decl;
			oberon_object_t * arg = type -> decl;
			for(int i = 0; i < num; i++)
			{
				desc = get_descriptor(ctx, arg -> type);
				name = new_string("%s%s", name, desc);
				arg = arg -> next;
			}

			break;
		case OBERON_TYPE_RECORD:
			assert(type -> module);
			assert(type -> module -> gen_mod);
			rec_id = type -> gen_type -> rec_id;
			name = new_string("%s$RECORD%i", type -> module -> name, rec_id);
			break;
		default:
			oberon_error(ctx, "get_record_full_name: unk type class %i", type -> class);
			break;
	}

	return name;
}

static char *
get_procedure_signature(oberon_context_t * ctx, oberon_type_t * proc)
{
	char * signature;
	char * desc;

	signature = new_string("(");

	int num = proc -> num_decl;
	oberon_object_t * arg = proc -> decl;
	for(int i = 0; i < num; i++)
	{
		desc = get_descriptor(ctx, arg -> type);
		signature = new_string("%s%s", signature, desc);
		arg = arg -> next;
	}

	desc = get_descriptor(ctx, proc -> base);
	signature = new_string("%s)%s", signature, desc);

	return signature;
}

static void
oberon_generate_procedure_class(oberon_context_t * ctx, oberon_type_t * proc)
{
	FILE * fp;
	char * cname;
	char * fname;
	char * signature;

	cname = get_class_full_name(ctx, proc);
	fname = new_string("%s.j", cname);

	fp = fopen(fname, "w");

	fprintf(fp, ".source SYSTEM\n");
	fprintf(fp, ".class  public abstract %s\n", cname);
	fprintf(fp, ".super  java/lang/Object\n\n");

	signature = get_procedure_signature(ctx, proc);

	fprintf(fp, ".method public <init>()V\n");
	fprintf(fp, "  aload_0\n");
	fprintf(fp, "  invokespecial java/lang/Object/<init>()V\n");
	fprintf(fp, "  return\n");
	fprintf(fp, ".end method\n\n");

	fprintf(fp, ".method public abstract invoke%s\n", signature);
	fprintf(fp, ".end method\n\n");

	fclose(fp);
}

static void
oberon_generate_record_class(oberon_context_t * ctx, oberon_type_t * rec)
{
	FILE * fp;
	char * cname;
	char * fname;

	/* Устанавливаем новоый id */
	rec -> gen_type -> rec_id = rec -> module -> gen_mod -> rec_id;
	rec -> module -> gen_mod -> rec_id += 1;

	cname = get_class_full_name(ctx, rec);
	fname = new_string("%s.j", cname);

	fp = fopen(fname, "w");

	fprintf(fp, ".source %s\n", rec -> module -> name);
	fprintf(fp, ".class  public %s\n", cname);
	fprintf(fp, ".super  java/lang/Object\n\n");

	rec -> gen_type -> fp = fp;
}

void
oberon_generator_init_type(oberon_context_t * ctx, oberon_type_t * type)
{
	gen_type_t * t = GC_MALLOC(sizeof *t);
	memset(t, 0, sizeof *t);
	type -> gen_type = t;

	switch(type -> class)
	{
		case OBERON_TYPE_VOID:
		case OBERON_TYPE_INTEGER:
		case OBERON_TYPE_BOOLEAN:
		case OBERON_TYPE_ARRAY:
		case OBERON_TYPE_REAL:
			break;
		case OBERON_TYPE_RECORD:
			oberon_generate_record_class(ctx, type);
			break;
		case OBERON_TYPE_PROCEDURE:
			oberon_generate_procedure_class(ctx, type);
			break;
		case OBERON_TYPE_POINTER:
			assert(type -> base -> class == OBERON_TYPE_VOID);
			break;
		default:
			oberon_error(ctx, "oberon_generator_init_type: unk calss %i", type -> class);
			break;
	}
}

static void
oberon_generate_object(oberon_context_t * ctx, FILE * fp, oberon_object_t * x)
{
	char * name;
	char * desc;

	name = x -> name;
	desc = get_descriptor(ctx, x -> type);
	switch(x -> class)
	{
		case OBERON_CLASS_VAR:
			fprintf(fp, ".field public static %s %s\n\n", name, desc);
			break;
		case OBERON_CLASS_FIELD:
			fprintf(fp, ".field public %s %s\n\n", name, desc);
			break;
		default:
			oberon_error(ctx, "oberon_generate_object: unk class %i", x -> class);
			break;
	}
}

void
oberon_generator_init_record(oberon_context_t * ctx, oberon_type_t * rec)
{
	FILE * fp;

	fp = rec -> gen_type -> fp;

	int num = rec -> num_decl;
	oberon_object_t * field = rec -> decl;
	for(int i = 0; i < num; i++)
	{
		oberon_generate_object(ctx, fp, field);
		field = field -> next;
	}

	fprintf(fp, ".method public <init>()V\n");
	fprintf(fp, "  aload_0\n");
	fprintf(fp, "  invokespecial java/lang/Object/<init>()V\n");
	fprintf(fp, "  return\n");
	fprintf(fp, ".end method\n");

	fclose(fp);
}

void
oberon_generator_init_var(oberon_context_t * ctx, oberon_object_t * var)
{
	gen_var_t * v = GC_MALLOC(sizeof *v);
	memset(v, 0, sizeof *v);
	var -> gen_var = v;

	gen_module_t * m = ctx -> mod -> gen_mod;	

	switch(var -> class)
	{
		case OBERON_CLASS_VAR_PARAM:
			oberon_error(ctx, "generator: VAR-parameters not implemented");
			break;
		case OBERON_CLASS_PARAM:
		case OBERON_CLASS_FIELD:
			break;
		case OBERON_CLASS_VAR:
			oberon_generate_object(ctx, m -> fp, var);
			break;
		default:
			oberon_error(ctx, "oberon_generator_init_var: unk var class %i", var -> class);
			break;
	}
}

void
oberon_generator_init_proc(oberon_context_t * ctx, oberon_object_t * proc)
{
	gen_proc_t * p = GC_MALLOC(sizeof *p);
	memset(p, 0, sizeof *p);
	proc -> gen_proc = p;

	if(proc -> local)
	{
		oberon_error(ctx, "generator: local procedures not implemented");
	}
}

void
oberon_generator_init_module(oberon_context_t * ctx, oberon_module_t * mod)
{
	gen_module_t * m = GC_MALLOC(sizeof *m);
	memset(m, 0, sizeof *m);
	mod -> gen_mod = m;

	int fnamesz = strlen(mod -> name) + 3;
	char fname[fnamesz + 1];
	snprintf(fname, fnamesz, "%s.j", mod -> name);

	FILE * fp;
	fp = fopen(fname, "w");
	assert(fp != NULL);

	fprintf(fp, ".source %s\n", mod -> name);
	fprintf(fp, ".class %s\n", mod -> name);
	fprintf(fp, ".super java/lang/Object\n\n");

	m -> fp = fp;
}

// =======================================================================
//   GENERATOR
// ======================================================================= 

static void
push_expr(oberon_context_t * ctx, FILE * fp, oberon_expr_t * expr);

void
oberon_generate_begin_module(oberon_context_t * ctx)
{
	gen_module_t * m = ctx -> mod -> gen_mod;
	fprintf(m -> fp, ".method public <init>()V\n");
	fprintf(m -> fp, "  aload_0\n");
	fprintf(m -> fp, "  invokespecial java/lang/Object/<init>()V\n");
}

void
oberon_generate_end_module(oberon_context_t * ctx)
{
	gen_module_t * m = ctx -> mod -> gen_mod;

	fprintf(m -> fp, "  .limit stack 32\n");
	fprintf(m -> fp, "  .limit locals 32\n");
	fprintf(m -> fp, "  return\n");
	fprintf(m -> fp, ".end method\n");
}

void
oberon_generate_begin_proc(oberon_context_t * ctx, oberon_object_t * proc)
{
	gen_module_t * m;
	char * signature;

	m = ctx -> mod -> gen_mod;
	signature = get_procedure_signature(ctx, proc -> type);

	fprintf(m -> fp, ".method public static %s%s\n", proc -> name, signature);
}

void
oberon_generate_call_proc(oberon_context_t * ctx, oberon_expr_t * desig)
{
	oberon_object_t * proc;
	gen_module_t * m;
	char * fullname;
	char * signature;

	assert(desig -> is_item);
	assert(desig -> item.mode == MODE_CALL);

	m = ctx -> mod -> gen_mod;
	proc = desig -> item.var;
	fullname = get_field_full_name(ctx, proc);
	signature = get_procedure_signature(ctx, proc -> type);

	int num = desig -> item.num_args;
	oberon_expr_t * arg = desig -> item.args;
	for(int i = 0; i < num; i++)
	{
		push_expr(ctx, m -> fp, arg);
		arg = arg -> next;
	}

	fprintf(m -> fp, "invokestatic %s%s\n", fullname, signature);
}

void
oberon_generate_end_proc(oberon_context_t * ctx)
{
	gen_module_t * m;
	m = ctx -> mod -> gen_mod;

	fprintf(m -> fp, "  .limit stack 32\n");
	fprintf(m -> fp, "  .limit locals 32\n");
	fprintf(m -> fp, ".end method\n\n");
}

void
oberon_generate_return(oberon_context_t * ctx, oberon_expr_t * expr)
{
	gen_module_t * m;

	m = ctx -> mod -> gen_mod;

	if(expr)
	{
		oberon_error(ctx, "oberon_generate_return: TODO return expr");
	}
	else
	{
		fprintf(m -> fp, "  return\n");
	}
}

static void
push_int(FILE * fp, long i)
{
	if(i == -1)
	{
		fprintf(fp, "iconst_m1\n");
	}
	else if(i >= 0 && i <= 5)
	{
		fprintf(fp, "iconst_%li\n", i);
	}
	else if(i >= -128 && i <= 127)
	{
		fprintf(fp, "bipush %li\n", i);
	}
	else if(i >= -32768 && i <= 32767)
	{
		fprintf(fp, "sipush %li\n", i);		
	}
	else if(i >= -2147483648 && i <= 2147483647)
	{
		fprintf(fp, "ldc %li\n", i);
	}
	else
	{
		fprintf(fp, "ldc2 %li\n", i);
	}
}

static void
push_float(FILE * fp, double f, int size)
{
	if(size <= 4)
	{
		if(f == 0.0)
		{
			fprintf(fp, "fconst_0\n");
		}
		if(f == 1.0)
		{
			fprintf(fp, "fconst_1\n");
		}
		if(f == 2.0)
		{
			fprintf(fp, "fconst_2\n");
		}
		else
		{
			fprintf(fp, "ldc %lf\n", f);
		}
	}
	else
	{
		if(f == 0.0)
		{
			fprintf(fp, "dconst_0\n");
		}
		if(f == 1.0)
		{
			fprintf(fp, "dconst_1\n");
		}
		else
		{
			fprintf(fp, "ldc2 %lf\n", f);
		}
	}
}

static void push_expr(oberon_context_t * ctx, FILE * fp, oberon_expr_t * expr);

static void
push_var(oberon_context_t * ctx, FILE * fp, oberon_object_t * var)
{
	if(var -> local)
	{
		int reg = var -> gen_var -> reg;
		char prefix = get_prefix(ctx, var -> type);
		fprintf(fp, "%cload %i\n", prefix, reg);
	}
	else
	{
		char * fullname = get_field_full_name(ctx, var);
		char * desc = get_descriptor(ctx, var -> type);
		fprintf(fp, "getstatic %s %s\n", fullname, desc);
	}
}

static void
push_item(oberon_context_t * ctx, FILE * fp, oberon_item_t * item)
{
	switch(item -> mode)
	{
		case MODE_VAR:
			push_var(ctx, fp, item -> var);
			break;
		case MODE_INTEGER:
			push_int(fp, item -> integer);
			break;
		case MODE_BOOLEAN:
			push_int(fp, item -> boolean);
			break;
		case MODE_CALL:
			oberon_error(ctx, "push_item: TODO call");
			break;
		case MODE_INDEX:
			oberon_error(ctx, "push_item: TODO index");
			break;
		case MODE_FIELD:
			oberon_error(ctx, "push_item: TODO field");
			break;
		case MODE_DEREF:
			oberon_error(ctx, "push_item: TODO deref");
			break;
		case MODE_NIL:
			fprintf(fp, "aconst_null\n");
			break;
		case MODE_NEW:
			oberon_error(ctx, "push_item: TODO new");
			break;
		case MODE_REAL:
			push_float(fp, item -> real, item -> result -> size);
			break;
		default:
			oberon_error(ctx, "push_item: unk mode %i", item -> mode);
			break;
	}
}

static void
push_operator(oberon_context_t * ctx, FILE * fp, oberon_oper_t * oper)
{
	char prefix = get_prefix(ctx, oper -> result);
	switch(oper -> op)
	{
		case OP_UNARY_MINUS:
			push_expr(ctx, fp, oper -> left);
			fprintf(fp, "%cneg\n", prefix);
			break;
		case OP_BITWISE_NOT:
			push_expr(ctx, fp, oper -> left);
			push_int(fp, -1);
			fprintf(fp, "%cxor\n", prefix);
			break;

		case OP_ADD:
			push_expr(ctx, fp, oper -> left);
			push_expr(ctx, fp, oper -> right);
			fprintf(fp, "%cadd\n", prefix);
			break;
		case OP_SUB:
			push_expr(ctx, fp, oper -> left);
			push_expr(ctx, fp, oper -> right);
			fprintf(fp, "%csub\n", prefix);
			break;
		case OP_MUL:
			push_expr(ctx, fp, oper -> left);
			push_expr(ctx, fp, oper -> right);
			fprintf(fp, "%cmul\n", prefix);
			break;
		case OP_DIV:
			push_expr(ctx, fp, oper -> left);
			push_expr(ctx, fp, oper -> right);
			fprintf(fp, "%cdiv\n", prefix);
			break;
		case OP_MOD:
			push_expr(ctx, fp, oper -> left);
			push_expr(ctx, fp, oper -> right);
			fprintf(fp, "%crem\n", prefix);
			break;
		case OP_BITWISE_AND:
			push_expr(ctx, fp, oper -> left);
			push_expr(ctx, fp, oper -> right);
			fprintf(fp, "%cand\n", prefix);
			break;
		case OP_BITWISE_XOR:
			push_expr(ctx, fp, oper -> left);
			push_expr(ctx, fp, oper -> right);
			fprintf(fp, "%cxor\n", prefix);
			break;
		case OP_BITWISE_OR:
			push_expr(ctx, fp, oper -> left);
			push_expr(ctx, fp, oper -> right);
			fprintf(fp, "%cor\n", prefix);
			break;

		case OP_EQ:
		case OP_NEQ:
		case OP_LSS:
		case OP_LEQ:
		case OP_GRT:
		case OP_GEQ:
		case OP_LOGIC_NOT:
		case OP_ABS:
			oberon_error(ctx, "push_oper: TODO op %i", oper -> op);
			break;
		default:
			oberon_error(ctx, "push_oper: unk op %i", oper -> op);
			break;
	}
}

static void
push_expr(oberon_context_t * ctx, FILE * fp, oberon_expr_t * expr)
{
	if(expr -> is_item)
	{
		push_item(ctx, fp, (oberon_item_t *) expr);
	}
	else
	{
		push_operator(ctx, fp, (oberon_oper_t *) expr);
	}
}

static void
store_expr(oberon_context_t * ctx, FILE * fp, oberon_expr_t * expr)
{
	assert(expr -> is_item);
	oberon_item_t * item = (oberon_item_t *) expr;

	char prefix;
	switch(item -> mode)
	{
		case MODE_VAR:
			if(item -> var -> local)
			{
				int reg = item -> var -> gen_var -> reg;
				prefix = get_prefix(ctx, item -> result);
				fprintf(fp, "%cstore %i\n", prefix, reg);
			}
			else
			{
				char * fullname = get_field_full_name(ctx, item -> var);
				char * desc = get_descriptor(ctx, item -> result);
				fprintf(fp, "putstatic %s %s\n", fullname, desc);
			}
			break;
		default:
			oberon_error(ctx, "store_expr: unk mode %i", item -> mode);
			break;
	}
}

void
oberon_generate_assign(oberon_context_t * ctx, oberon_expr_t * src, oberon_expr_t * dst)
{
	gen_module_t * m;
	m = ctx -> mod -> gen_mod;

	push_expr(ctx, m -> fp, src);
	store_expr(ctx, m -> fp, dst);
}

void
oberon_generate_code(oberon_context_t * ctx)
{
	printf("generate code\n");
}

void
oberon_generator_dump(oberon_context_t * ctx, char * path)
{
	printf("jit: dump code\n");
}

void *
oberon_generator_get_procedure(oberon_context_t * ctx, const char * name)
{
	printf("jit: get pointer to procedure %s\n", name);
	return NULL;
}

void *
oberon_generator_get_var(oberon_context_t * ctx, const char * name)
{
	printf("jit: get pointer to var %s\n", name);
	return NULL;
}