/* +--------------------------------------------------------------------------+
** |                          _   _       _                                   |
** |                         | \ | |     (_)                                  |
** |                         |  \| | ___  _  __ _                             |
** |                         | . ` |/ _ \| |/ _` |                            |
** |                         | |\  | (_) | | (_| |                            |
** |                         |_| \_|\___/| |\__,_|                            |
** |                                    _/ |                                  |
** |                                   |__/                                   |
** +--------------------------------------------------------------------------+
** | Copyright (c) 2022 Francesco Cozzuto <francesco.cozzuto@gmail.com>       |
** +--------------------------------------------------------------------------+
** | This file is part of The Noja Interpreter.                               |
** |                                                                          |
** | The Noja Interpreter is free software: you can redistribute it and/or    |
** | modify it under the terms of the GNU General Public License as published |
** | by the Free Software Foundation, either version 3 of the License, or (at |
** | your option) any later version.                                          |
** |                                                                          |
** | The Noja Interpreter is distributed in the hope that it will be useful,  |
** | but WITHOUT ANY WARRANTY; without even the implied warranty of           |
** | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General |
** | Public License for more details.                                         |
** |                                                                          |
** | You should have received a copy of the GNU General Public License along  |
** | with The Noja Interpreter. If not, see <http://www.gnu.org/licenses/>.   |
** +--------------------------------------------------------------------------+ 
*/

#include <assert.h>
#include <string.h>
#include <stdlib.h>
#include <stdio.h>
#include "compiler/parse.h"
#include "compiler/compile.h"
#include "runtime/runtime.h"
#include "builtins/basic.h"

static const char usage[] = 
	"Usage patterns:\n"
	"    $ noja run file.noja\n"
	"    $ noja run inline \"print('some noja code');\"\n"
	"    $ noja dis file.noja\n"
	"    $ noja dis inline \"print('some noja code');\"\n";

static void print_error(const char *type, Error *error)
{
	if(type == NULL)
		fprintf(stderr, "Error");
	else if(error->internal)
		fprintf(stderr, "Internal Error");
	else
		fprintf(stderr, "%s Error", type);

	fprintf(stderr, ": %s.", error->message);

#ifdef DEBUG
	if(error->file != NULL)
	{
		if(error->line > 0 && error->func != NULL)
			fprintf(stderr, " (Reported in %s:%d in %s)", error->file, error->line, error->func);
		else if(error->line > 0 && error->func == NULL)
			fprintf(stderr, " (Reported in %s:%d)", error->file, error->line);
		else if(error->line < 1 && error->func != NULL)
			fprintf(stderr, " (Reported in %s in %s)", error->file, error->func);
	}
#endif
	
	fprintf(stderr, "\n");
}

static Executable *build(Source *src)
{
	Executable *exe;
	
	// Create a bump-pointer allocator to hold the AST.
	BPAlloc *alloc = BPAlloc_Init(-1);

	if(alloc == NULL)
	{
		fprintf(stderr, "Internal Error: Couldn't allocate bump-pointer allocator to hold the AST.\n");
		return 0;
	}

	Error error;
	Error_Init(&error);

	// NOTE: The AST is stored in the BPAlloc. It's
	//       lifetime is the same as the pool.
	AST *ast = parse(src, alloc, &error);

	if(ast == NULL)
	{
		assert(error.occurred);
		print_error("Parsing", &error);
		Error_Free(&error);
		BPAlloc_Free(alloc);
		return 0;
	}
	
	exe = compile(ast, alloc, &error);

	// We're done with the AST, independently from
	// the compilation result.
	BPAlloc_Free(alloc);

	if(exe == NULL)
	{
		assert(error.occurred);
		print_error("Compilation", &error);
		Error_Free(&error);
		return 0;
	}

	return exe;
}

static _Bool interpret(Source *src)
{
	Executable *exe = build(src);

	if(exe == NULL)
		return 0;

	Runtime *runt = Runtime_New(-1, 1024*1024, NULL, NULL);

	if(runt == NULL)
	{
		Error error;
		Error_Init(&error);
		Error_Report(&error, 1, "Couldn't initialize runtime");
		print_error(NULL, &error);
		Error_Free(&error);
		Executable_Free(exe);
		return 0;
	}

	// We use a [RuntimeError] instead of a simple [Error]
	// because the [RuntimeError] makes a snapshot of the
	// runtime state when an error is reported. Other than
	// this fact they are interchangable. Any function that
	// expects a pointer to [Error] can receive a [RuntimeError]
	// upcasted to [Error].
	RuntimeError error;
	RuntimeError_Init(&error, runt); // Here we specify the runtime to snapshot in case of failure.
	
	Object *bins = Object_NewStaticMap(bins_basic, runt, (Error*) &error);

	if(bins == NULL)
	{
		assert(error.base.occurred == 1);
		print_error(NULL, (Error*) &error);
		RuntimeError_Free(&error);
		Executable_Free(exe);
		Runtime_Free(runt);
		return 0;
	}

	Runtime_SetBuiltins(runt, bins);

	Object *rets[8];
	unsigned int maxretc = sizeof(rets)/sizeof(rets[0]);

	int retc = run(runt, (Error*) &error, exe, 0, NULL, NULL, 0, rets, maxretc);

	// NOTE: The pointer to the builtins object is invalidated
	//       now because it may be moved by the garbage collector.

	if(retc < 0)
	{
		print_error("Runtime", (Error*) &error);

		if(error.snapshot == NULL)
			fprintf(stderr, "No snapshot available.\n");
		else
			Snapshot_Print(error.snapshot, stderr);

		RuntimeError_Free(&error);
	}

	Runtime_Free(runt);
	Executable_Free(exe);

	return retc > -1;
}

static _Bool disassemble(Source *src)
{
	Executable *exe = build(src);

	if(exe == NULL)
		return 0;

	Executable_Dump(exe);
	return 1;
}

static _Bool interpret_file(const char *file)
{
	Error error;
	Error_Init(&error);
	
	Source *src = Source_FromFile(file, &error);

	if(src == NULL)
	{
		assert(error.occurred == 1);
		print_error(NULL, &error);
		Error_Free(&error);
		return 0;
	}

	_Bool r = interpret(src);

	Source_Free(src);
	return r;
}

static _Bool interpret_code(const char *code)
{
	Error error;
	Error_Init(&error);
	
	Source *src = Source_FromString(NULL, code, -1, &error);

	if(src == NULL)
	{
		assert(error.occurred);
		print_error(NULL, &error);
		Error_Free(&error);
		return 0;
	}

	_Bool r = interpret(src);

	Source_Free(src);
	return r;
}

static _Bool disassemble_file(const char *file)
{
	Error error;
	Error_Init(&error);
	
	Source *src = Source_FromFile(file, &error);

	if(src == NULL)
	{
		assert(error.occurred == 1);
		print_error(NULL, &error);
		Error_Free(&error);
		return 0;
	}

	_Bool r = disassemble(src);

	Source_Free(src);
	return r;
}

static _Bool disassemble_code(const char *code)
{
	Error error;
	Error_Init(&error);
	
	Source *src = Source_FromString(NULL, code, -1, &error);

	if(src == NULL)
	{
		assert(error.occurred);
		print_error(NULL, &error);
		Error_Free(&error);
		return 0;
	}

	_Bool r = disassemble(src);

	Source_Free(src);
	return r;
}

int main(int argc, char **argv)
{
	assert(argc > 0);

	if(argc == 1)
	{
		// $ noja
		fprintf(stderr, "Error: Incorrect usage.\n\n");
		fprintf(stderr, usage);
		return -1;
	}

	if(!strcmp(argv[1], "run"))
	{
		Error error;
		Error_Init(&error);
		
		if(argc == 2)
		{
			Error_Report(&error, 0, "Missing source file");
			print_error(NULL, &error);
			Error_Free(&error);
			return -1;
		}

		_Bool r;

		if(!strcmp(argv[2], "inline"))
		{
			if(argc == 3)
			{
				Error_Report(&error, 0, "Missing source string");
				print_error(NULL, &error);
				Error_Free(&error);
				return -1;
			}
			r = interpret_code(argv[3]);
		}
		else
			r = interpret_file(argv[2]);
		return r ? 0 : -1;
	}
	
	if(!strcmp(argv[1], "dis"))
	{
		Error error;
		Error_Init(&error);
			
		if(argc == 2)
		{
			Error_Report(&error, 0, "Missing source file");
			print_error(NULL, &error);
			Error_Free(&error);
			return -1;
		}

		_Bool r;

		if(!strcmp(argv[2], "inline"))
		{
			if(argc == 3)
			{
				Error_Report(&error, 0, "Missing source string");
				print_error(NULL, &error);
				Error_Free(&error);
				return -1;
			}

			r = disassemble_code(argv[3]);
		}
		else
			r = disassemble_file(argv[2]);
		return r ? 0 : -1;
	}

	if(!strcmp(argv[1], "help"))
	{
		fprintf(stdout, usage);
		return 0;
	}

	fprintf(stderr, "Error: Incorrect usage.\n\n");
	fprintf(stderr, usage);
	return -1;
}