#include <stdio.h>
#include <stdlib.h>
#include <stdarg.h>
#include <ctype.h>
#include <string.h>
#include <assert.h>

#include "oberon.h"
#include "generator.h"

#include <libgccjit.h>

/*
 * oberon_var_t -> gvar == gcc_jit_lvalue;
 * oberon_type_t -> gtype == gcc_jit_type;
 * oberon_context_t -> gctx == gen_context_t;
 */ 

typedef struct
{
	gcc_jit_context * gcc_context;
	gcc_jit_block * gcc_block;
	gcc_jit_result * gcc_result;
} gen_context_t;

static void printcontext(oberon_context_t * ctx, char * s)
{
/*
	gen_context_t * gen_context = ctx -> gen_context;
	gcc_jit_context * gcc_context = gen_context -> gcc_context;
	gcc_jit_block * gcc_block = gen_context -> gcc_block;

	printf("%s:\n", s);
	printf("  ctx     = %p:\n", ctx);
	printf("  gctx    = %p:\n", gctx);
	printf("  context = %p:\n", context);
	printf("  block   = %p:\n", block);
*/
}

// =======================================================================
//   ALLOC
// ======================================================================= 

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

	gcc_jit_context * gcc_context;
	gcc_context = gcc_jit_context_acquire();

	ctx -> gen_context = gen_context;
	gen_context -> gcc_context = gcc_context;

	printcontext(ctx, "oberon_generator_init_context");
}

void
oberon_generator_destroy_context(oberon_context_t * ctx)
{
	printcontext(ctx, "oberon_generator_destroy_context");

	gen_context_t * gen_context = ctx -> gen_context;
	gcc_jit_context * gcc_context = gen_context -> gcc_context;

	gcc_jit_context_release(gcc_context);
}

void
oberon_generator_init_type(oberon_context_t * ctx, oberon_type_t * type)
{
	printcontext(ctx, "oberon_generator_init_type");

	gen_context_t * gen_context = ctx -> gen_context;
	gcc_jit_context * gcc_context = gen_context -> gcc_context;

	gcc_jit_type * gen_type;
	if(type -> class == OBERON_TYPE_INTEGER)
	{
		gen_type = gcc_jit_context_get_int_type(gcc_context, type -> size, 1);
	}
	else if(type -> class == OBERON_TYPE_BOOLEAN)
	{
		gen_type = gcc_jit_context_get_type(gcc_context, GCC_JIT_TYPE_BOOL);
	}
	else
	{
		oberon_error(ctx, "oberon_generator_init_type: invalid type class %i", type -> class);
	}

	type -> gen_type = gen_type;
}

void
oberon_generator_init_var(oberon_context_t * ctx, oberon_var_t * var)
{
	printcontext(ctx, "oberon_generator_init_var");

	gen_context_t * gen_context = ctx -> gen_context;
	gcc_jit_context * gcc_context = gen_context -> gcc_context;
	gcc_jit_type * gen_type = var -> type -> gen_type;
	const char * name = var -> name;

	gcc_jit_lvalue * gen_var;
	gen_var = gcc_jit_context_new_global(gcc_context, NULL, GCC_JIT_GLOBAL_INTERNAL, gen_type, name);

	var -> gen_var = gen_var;
}

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

static gcc_jit_rvalue *
oberon_generate_rvalue_from_item(oberon_context_t * ctx, oberon_item_t * item)
{
	printcontext(ctx, "oberon_generate_rvalue_from_item");

	gen_context_t * gen_context = ctx -> gen_context;
	gcc_jit_context * gcc_context = gen_context -> gcc_context;

	gcc_jit_rvalue * right;
	if(item -> mode == MODE_VAR)
	{
		gcc_jit_lvalue * gen_var = item -> var -> gen_var;
		right = gcc_jit_lvalue_as_rvalue(gen_var);
		printf("PUSH (var) %s\n", item -> var -> name);
	}
	else if(item -> mode == MODE_INTEGER)
	{
		gcc_jit_type * int_type = gcc_jit_context_get_type(gcc_context, GCC_JIT_TYPE_INT);
		right = gcc_jit_context_new_rvalue_from_int(gcc_context, int_type, item -> integer);
		printf("PUSH (int) %i\n", item -> integer);
	}
	else if(item -> mode == MODE_BOOLEAN)
	{
		gcc_jit_type * bool_type = gcc_jit_context_get_type(gcc_context, GCC_JIT_TYPE_BOOL);
		if(item -> boolean)
		{
			right = gcc_jit_context_one(gcc_context, bool_type);
		}
		else
		{
			right = gcc_jit_context_zero(gcc_context, bool_type);			
		}
		printf("PUSH (bool) %i\n", item -> boolean);
	}
	else
	{
		oberon_error(ctx, "oberon_generate_push: invalid mode %i", item -> mode);
	}

	return right;
}

void
oberon_generate_begin_module(oberon_context_t * ctx)
{
	printcontext(ctx, "oberon_generate_begin_module");

	gen_context_t * gen_context = ctx -> gen_context;
	gcc_jit_context * gcc_context = gen_context -> gcc_context;

	gcc_jit_type * void_type = gcc_jit_context_get_type(gcc_context, GCC_JIT_TYPE_VOID);
	gcc_jit_function * func = gcc_jit_context_new_function(
		gcc_context, NULL, GCC_JIT_FUNCTION_EXPORTED, void_type, "BEGIN", 0, NULL, 0
	);
	gcc_jit_block * gcc_block = gcc_jit_function_new_block(func, NULL);

	gen_context -> gcc_block = gcc_block;
}

void
oberon_generate_end_module(oberon_context_t * ctx)
{
	printcontext(ctx, "oberon_generate_end_module");

	gen_context_t * gen_context = ctx -> gen_context;
	gcc_jit_block * gcc_block = gen_context -> gcc_block;

	gcc_jit_block_end_with_void_return(gcc_block, NULL);

	gen_context -> gcc_block = NULL;
}

void
oberon_generate_assign(oberon_context_t * ctx, oberon_item_t * src, oberon_item_t * dst)
{
	printcontext(ctx, "oberon_generate_assign");

	gen_context_t * gen_context = ctx -> gen_context;
	gcc_jit_block * gcc_block = gen_context -> gcc_block;

	gcc_jit_lvalue * left;
	gcc_jit_rvalue * right;

	right = oberon_generate_rvalue_from_item(ctx, src);

	if(dst -> mode == MODE_VAR)
	{
		printf("STORE %s\n", dst -> var -> name);
		left = dst -> var -> gen_var;
	}
	else
	{
		oberon_error(ctx, "oberon_generate_assign: invalid assignment");
	}	

	gcc_jit_block_add_assignment(gcc_block, NULL, left, right);
}

void
oberon_generate_code(oberon_context_t * ctx)
{
	gen_context_t * gen_context = ctx -> gen_context;
	gcc_jit_context * gcc_context = gen_context -> gcc_context;

	gcc_jit_result * gcc_result;
	gcc_result = gcc_jit_context_compile(gcc_context);

	gen_context -> gcc_result = gcc_result;
	ctx -> mod -> begin = gcc_jit_result_get_code(gcc_result, "BEGIN");
}