#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>

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)
{
	gen_type_t * gen_type = malloc(sizeof *gen_type);
	memset(gen_type, 0, sizeof *gen_type);
	type -> gen_type = gen_type;

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

	gcc_jit_type * gcc_type;
	if(type -> class == OBERON_TYPE_VOID)
	{
		gcc_type = gcc_jit_context_get_type(gcc_context, GCC_JIT_TYPE_VOID);
	}
	else if(type -> class == OBERON_TYPE_INTEGER)
	{
		gcc_type = gcc_jit_context_get_int_type(gcc_context, type -> size, 1);
	}
	else if(type -> class == OBERON_TYPE_BOOLEAN)
	{
		gcc_type = gcc_jit_context_get_type(gcc_context, GCC_JIT_TYPE_BOOL);
	}
	else if(type -> class == OBERON_TYPE_PROCEDURE)
	{
		gcc_type = NULL; // not used
	}
	else if(type -> class == OBERON_TYPE_ARRAY)
	{
		if(type -> dim != 1)
		{
			oberon_error(ctx, "multidimension and open arrays not supported");
		}
		
		gen_type_t * gen_base = type -> base -> gen_type;
		gcc_jit_type * gcc_base = gen_base -> gcc_type;

		gcc_type = gcc_jit_context_new_array_type(gcc_context, NULL, gcc_base, type -> size);
	}
	else
	{
		oberon_error(ctx, "oberon_generator_init_type: invalid type class %i", type -> class);
	}

	gen_type -> gcc_type = gcc_type;
}

void
oberon_generator_init_var(oberon_context_t * ctx, oberon_object_t * var)
{
	gen_context_t * gen_context = ctx -> gen_context;
	gen_type_t * gen_type = var -> type -> gen_type;

	gen_var_t * gen_var = malloc(sizeof *gen_var);
	memset(gen_var, 0, sizeof *gen_var);
	var -> gen_var = gen_var;

	gcc_jit_context * gcc_context = gen_context -> gcc_context;
	gcc_jit_type * gcc_type = gen_type -> gcc_type;
	const char * name = var -> name;

	// TODO var param
	if(var -> class == OBERON_CLASS_VAR)
	{
		gen_var -> gcc_lvalue = gcc_jit_context_new_global(
			gcc_context, NULL, GCC_JIT_GLOBAL_INTERNAL, gcc_type, name
		);
	}
	else if(var -> class == OBERON_CLASS_PARAM)
	{
		gen_var -> gcc_param = gcc_jit_context_new_param(gcc_context, NULL, gcc_type, name);
		gen_var -> gcc_lvalue = gcc_jit_param_as_lvalue(gen_var -> gcc_param);
	}
	else
	{
		oberon_error(ctx, "oberon_generator_init_var: invalid class %i", var -> class);
	}
}

void
oberon_generator_init_proc(oberon_context_t * ctx, oberon_object_t * proc)
{
	assert(proc -> class == OBERON_CLASS_PROC);

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

	gen_proc_t * gen_proc = malloc(sizeof *gen_proc);
	memset(gen_proc, 0, sizeof *gen_proc);
	proc -> gen_proc = gen_proc;

	const char * name = proc -> name;
	gen_type_t * gen_result_type = proc -> type -> base -> gen_type;
	gcc_jit_type * result_type = gen_result_type -> gcc_type;

	/* Строим список параметров */
	int num_param = proc -> type -> num_decl;
	oberon_object_t * o = proc -> type -> decl;
	gcc_jit_param * params[num_param];
	for(int i = 0; i < num_param; i++)
	{
		gen_var_t * param_var = o -> gen_var;
		params[i] = param_var -> gcc_param;
		o = o -> next;
	}

	gcc_jit_function * gcc_func;
	gcc_func = gcc_jit_context_new_function(
		gcc_context, NULL, GCC_JIT_FUNCTION_EXPORTED, result_type, name, num_param, params, 0
	);

	gen_proc -> gcc_func = gcc_func;
}

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

static gcc_jit_rvalue * rvalue_from_expr(oberon_context_t * ctx, oberon_expr_t * expr);

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_begin_proc(oberon_context_t * ctx, oberon_object_t * proc)
{
	gen_context_t * gen_context = ctx -> gen_context;
	gen_proc_t * gen_proc = proc -> gen_proc;

	gcc_jit_function * func = gen_proc -> gcc_func;
	gcc_jit_block * gcc_block = gcc_jit_function_new_block(func, NULL);

	// TODO make stack for block
	gen_context -> gcc_block = gcc_block;
}

void
oberon_generate_call_proc(oberon_context_t * ctx, oberon_expr_t * desig)
{
	gen_context_t * gen_context = ctx -> gen_context;
	gcc_jit_block * block = gen_context -> gcc_block;

	gcc_jit_rvalue * return_value;
	return_value = rvalue_from_expr(ctx, desig);
	gcc_jit_block_add_eval(block, NULL, return_value);
}

void
oberon_generate_end_proc(oberon_context_t * ctx)
{
	gen_context_t * gen_context = ctx -> gen_context;
	gen_context -> gcc_block = NULL;
}

void
oberon_generate_return(oberon_context_t * ctx, oberon_expr_t * expr)
{
	gen_context_t * gen_context = ctx -> gen_context;
	gcc_jit_block * gcc_block = gen_context -> gcc_block;

	if(expr == NULL)
	{
		gcc_jit_block_end_with_void_return(gcc_block, NULL);
	}
	else
	{
		gcc_jit_rvalue * r = rvalue_from_expr(ctx, expr);
		gcc_jit_block_end_with_return(gcc_block, NULL, r);
	}
}

static gcc_jit_lvalue *
lvalue_from_expr(oberon_context_t *ctx, oberon_expr_t * expr)
{
	gcc_jit_lvalue * left;
	oberon_item_t * item;

	if(expr -> is_item)
	{
		item = (oberon_item_t *) expr;
		if(item -> mode != MODE_VAR)
		{
			oberon_error(ctx, "invalid lvalue expression");
		}
		gen_var_t * gen_var = item -> var -> gen_var;
		left = gen_var -> gcc_lvalue;
	}
	else
	{
		oberon_error(ctx, "invalid lvalue expression");
	}

	return left;
}

static gcc_jit_rvalue *
rvalue_from_item(oberon_context_t * ctx, oberon_item_t * 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)
	{
		assert(item -> var -> class == OBERON_CLASS_VAR
			|| item -> var -> class == OBERON_CLASS_PARAM);
		gen_var_t * gen_var = item -> var -> gen_var;
		right = gcc_jit_lvalue_as_rvalue(gen_var -> gcc_lvalue);
	}
	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);
	}
	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);			
		}
	}
	else if(item -> mode == MODE_CALL)
	{
		assert(item -> var -> class == OBERON_CLASS_PROC);

		gen_proc_t * gen_proc = item -> var -> gen_proc;

		int num_args = item -> num_args;
		gcc_jit_rvalue *args[num_args];

		oberon_expr_t * expr = item -> args;
		for(int i = 0; i < num_args; i++)
		{
			args[i] = rvalue_from_expr(ctx, expr);
			expr = expr -> next;
		}

		gcc_jit_function * func = gen_proc -> gcc_func;
		right = gcc_jit_context_new_call(
	                gcc_context, NULL, func, num_args, args
		);
	}
	else
	{
		oberon_error(ctx, "oberon_generate_push: invalid mode %i", item -> mode);
	}

	return right;
}

struct {
	int type; // 0 - unary, 1 - binary, 2 - comp
	union {
		enum gcc_jit_unary_op unary_op;
		enum gcc_jit_binary_op binary_op;
		enum gcc_jit_comparison comp_op;
	};
} op_table[] = {
	{ 0, .unary_op = GCC_JIT_UNARY_OP_LOGICAL_NEGATE },
	{ 0, .unary_op = GCC_JIT_UNARY_OP_MINUS },

	{ 1, .binary_op = GCC_JIT_BINARY_OP_PLUS },
	{ 1, .binary_op = GCC_JIT_BINARY_OP_MINUS },
	{ 1, .binary_op = GCC_JIT_BINARY_OP_DIVIDE },
	{ 1, .binary_op = GCC_JIT_BINARY_OP_MODULO },
	{ 1, .binary_op = GCC_JIT_BINARY_OP_LOGICAL_AND },
	{ 1, .binary_op = GCC_JIT_BINARY_OP_LOGICAL_OR },

	{ 2, .comp_op = GCC_JIT_COMPARISON_EQ },
	{ 2, .comp_op = GCC_JIT_COMPARISON_NE },
	{ 2, .comp_op = GCC_JIT_COMPARISON_LT },
	{ 2, .comp_op = GCC_JIT_COMPARISON_LE },
	{ 2, .comp_op = GCC_JIT_COMPARISON_GT },
	{ 2, .comp_op = GCC_JIT_COMPARISON_GE }
};

static gcc_jit_rvalue *
rvalue_from_operator(oberon_context_t * ctx, oberon_oper_t * operator)
{
	gcc_jit_rvalue * right;

	gen_context_t * gen_context = ctx -> gen_context;
	gen_type_t * gen_type = operator -> result -> gen_type;
	gcc_jit_context * gcc_context = gen_context -> gcc_context;
	gcc_jit_type * result_type = gen_type -> gcc_type;

	int expr_type = op_table[operator -> op].type;
	if(expr_type == 0)
	{
		enum gcc_jit_unary_op op = op_table[operator -> op].unary_op;
		gcc_jit_rvalue * l = rvalue_from_expr(ctx, operator -> left);
		right = gcc_jit_context_new_unary_op(gcc_context, NULL, op, result_type, l);
	}
	else if(expr_type == 1)
	{
		enum gcc_jit_unary_op op = op_table[operator -> op].binary_op;
		gcc_jit_rvalue * l = rvalue_from_expr(ctx, operator -> left);
		gcc_jit_rvalue * r = rvalue_from_expr(ctx, operator -> right);
		right = gcc_jit_context_new_binary_op(gcc_context, NULL, op, result_type, l, r);
	}
	else if(expr_type == 2)
	{
		enum gcc_jit_comparison op = op_table[operator -> op].comp_op;
		gcc_jit_rvalue * l = rvalue_from_expr(ctx, operator -> left);
                gcc_jit_rvalue * r = rvalue_from_expr(ctx, operator -> right);
		right = gcc_jit_context_new_comparison(gcc_context, NULL, op, l, r);
	}
	else
	{
		oberon_error(ctx, "rvalue_from_operator: wat");
	}

	return right;
}

static gcc_jit_rvalue *
rvalue_from_expr(oberon_context_t * ctx, oberon_expr_t * expr)
{
	gcc_jit_rvalue * right;

	if(expr -> is_item)
	{
		oberon_item_t * item = (oberon_item_t *) expr;
		right = rvalue_from_item(ctx, item);
	}
	else
	{
		oberon_oper_t * operator = (oberon_oper_t *) expr;
		right = rvalue_from_operator(ctx, operator);
	}

	return right;
}

void
oberon_generate_assign(oberon_context_t * ctx, oberon_expr_t * src, oberon_expr_t * dst)
{
	gcc_jit_lvalue * left;
	left = lvalue_from_expr(ctx, dst);

	gcc_jit_rvalue * right;
	right = rvalue_from_expr(ctx, src);

	gen_context_t * gen_context = ctx -> gen_context;
	gcc_jit_block * gcc_block = gen_context -> gcc_block;
	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");
}