#include "../include/parser.h"
#include "../include/ast.h"
#include "../include/compiler.h"
#include "../include/std/misc.h"
#include "../include/std/file.h"
#include "../include/std/mem.h"
#include "../include/std/log.h"
#include <stdio.h>
#include <stdlib.h>
#include <assert.h>

static CHECK_RESULT int parser_queue_file(Parser *self, BufferView path);
static CHECK_RESULT int parser_parse_body(Parser *self, Ast *ast);

int parser_thread_data_init(ParserThreadData *self) {
    am_memset(&self->allocator, 0, sizeof(self->allocator));
    am_memset(&self->thread, 0, sizeof(self->thread));
    self->status = PARSER_THREAD_STATUS_NEW;
    return scoped_allocator_init(&self->allocator);
}

int parser_thread_data_deinit(ParserThreadData *self) {
    scoped_allocator_deinit(&self->allocator);
    return amal_thread_deinit(&self->thread);
}

int parser_thread_data_start(ParserThreadData *self, AmalThreadCallbackFunc callback_func, void *userdata) {
    return_if_error(amal_thread_deinit(&self->thread));
    return_if_error(amal_thread_create(&self->thread, AMAL_THREAD_JOINABLE, "Parser", callback_func, userdata));
    self->status = PARSER_THREAD_STATUS_RUNNING;
    return 0;
}

int parser_thread_data_join(ParserThreadData *self, void **result) {
    int retval;
    if(self->status == PARSER_THREAD_STATUS_NEW)
        return 0;
    retval = amal_thread_join(&self->thread, result);
    if(retval == 0 || retval == AMAL_THREAD_NOT_JOINABLE)
        self->status = PARSER_THREAD_STATUS_IDLE;
    return retval;
}

int parser_init(Parser *self, amal_compiler *compiler, ScopedAllocator *allocator) {
    self->allocator = allocator;
    self->compiler = compiler;
    self->started = bool_false;
    return buffer_init(&self->ast_objects, self->allocator);
}

/*
LHS = 'const'|'var' IDENTIFIER
*/
static CHECK_RESULT int parser_parse_lhs(Parser *self, LhsExpr **result) {
    bool isConst;
    BufferView var_name;
    *result = NULL;

    return_if_error(tokenizer_consume_if(&self->tokenizer, TOK_CONST, &isConst));
    if(!isConst) {
        bool isVar;
        return_if_error(tokenizer_consume_if(&self->tokenizer, TOK_VAR, &isVar));
        if(!isVar)
            return PARSER_OK;
    }

    return_if_error(tokenizer_accept(&self->tokenizer, TOK_IDENTIFIER));
    var_name = self->tokenizer.value.identifier;
    amal_log_debug("var name: %.*s", (int)var_name.size, var_name.data);
    return_if_error(scoped_allocator_alloc(self->allocator, sizeof(LhsExpr), (void**)result));
    lhsexpr_init(*result, isConst, var_name);
    return PARSER_OK;
}

/*
FUNC_DECL = '(' PARAM* ')' '{' BODY* '}'
*/
static CHECK_RESULT int parser_parse_function_decl(Parser *self, FunctionDecl **func_decl) {
    bool result;
    *func_decl = NULL;

    return_if_error(tokenizer_consume_if(&self->tokenizer, TOK_OPEN_PAREN, &result));
    if(!result)
        return PARSER_OK;

    /* TODO: Parse parameters */
    return_if_error(tokenizer_accept(&self->tokenizer, TOK_CLOSING_PAREN));
    /* TODO: Parse return types */
    return_if_error(tokenizer_accept(&self->tokenizer, TOK_OPEN_BRACE));

    return_if_error(scoped_allocator_alloc(self->allocator, sizeof(FunctionDecl), (void**)func_decl));
    return_if_error(funcdecl_init(*func_decl, self->allocator));

    for(;;) {
        Ast body_obj;
        return_if_error(tokenizer_consume_if(&self->tokenizer, TOK_CLOSING_BRACE, &result));
        if(result)
            break;
        
        return_if_error(parser_parse_body(self, &body_obj));
        return_if_error(funcdecl_add_to_body(*func_decl, body_obj));
    }
    return PARSER_OK;
}

/*
FUNC_CALL = IDENTIFIER '(' ARGS* ')'
*/
static CHECK_RESULT int parser_parse_function_call(Parser *self, FunctionCall **func_call) {
    bool result;
    BufferView func_name;
    *func_call = NULL;

    return_if_error(tokenizer_consume_if(&self->tokenizer, TOK_IDENTIFIER, &result));
    if(!result)
        return PARSER_OK;
    
    func_name = self->tokenizer.value.identifier;
    return_if_error(tokenizer_accept(&self->tokenizer, TOK_OPEN_PAREN));
    /* TODO: Parse arguments */
    return_if_error(tokenizer_accept(&self->tokenizer, TOK_CLOSING_PAREN));

    return_if_error(scoped_allocator_alloc(self->allocator, sizeof(FunctionCall), (void**)func_call));
    funccall_init(*func_call, func_name);
    return PARSER_OK;
}

/*
IMPORT = IMPORT_SYMBOL
*/
static CHECK_RESULT int parser_parse_import(Parser *self, Import **import) {
    bool result;

    return_if_error(tokenizer_consume_if(&self->tokenizer, TOK_IMPORT, &result));
    if(!result)
        return PARSER_OK;
    
    return_if_error(scoped_allocator_alloc(self->allocator, sizeof(Import), (void**)import));
    import_init(*import, self->tokenizer.value.string);
    return PARSER_OK;
}

/*
RHS = FUNC_DECL | FUNC_CALL | IMPORT
*/
static CHECK_RESULT int parser_parse_rhs(Parser *self, Ast *rhs_expr) {
    FunctionDecl *func_decl;
    FunctionCall *func_call;
    Import *import;

    return_if_error(parser_parse_function_decl(self, &func_decl));
    if(func_decl) {
        rhs_expr->type = AST_FUNCTION_DECL;
        rhs_expr->value.func_decl = func_decl;
        return PARSER_OK;
    }

    return_if_error(parser_parse_function_call(self, &func_call));
    if(func_call) {
        rhs_expr->type = AST_FUNCTION_CALL;
        rhs_expr->value.func_call = func_call;
        return PARSER_OK;
    }

    return_if_error(parser_parse_import(self, &import));
    if(import) {
        rhs_expr->type = AST_IMPORT;
        rhs_expr->value.import = import;
        return_if_error(parser_queue_file(self, import->path));
        return PARSER_OK;
    }

    /* TODO: Convert token to string */
    tokenizer_print_error(&self->tokenizer, "Expected function declaration or function call");
    return PARSER_UNEXPECTED_TOKEN;
}

/*
BODY = (LHS '=' RHS) |
       RHS
*/
int parser_parse_body(Parser *self, Ast *ast) {
    LhsExpr *lhs_expr;
    Ast rhs_expr;

    return_if_error(parser_parse_lhs(self, &lhs_expr));
    if(lhs_expr)
        return_if_error(tokenizer_accept(&self->tokenizer, TOK_EQUALS));
    
    return_if_error(parser_parse_rhs(self, &rhs_expr));
    if(lhs_expr) {
        lhs_expr->rhs_expr = rhs_expr;
        ast->type = AST_LHS;
        ast->value.lhs_expr = lhs_expr;
    } else {
        *ast = rhs_expr;
    }
    return PARSER_OK;
}

/*
ROOT = BODY*
*/
int parser_parse_buffer(Parser *self, BufferView code_buffer, BufferView buffer_name) {
    Ast ast;
    return_if_error(tokenizer_init(&self->tokenizer, code_buffer, buffer_name));

    for(;;) {
        bool isEof;
        return_if_error(tokenizer_consume_if(&self->tokenizer, TOK_END_OF_FILE, &isEof));
        if(isEof)
            break;
        
        return_if_error(parser_parse_body(self, &ast));
        return_if_error(buffer_append(&self->ast_objects, &ast, sizeof(ast)));
    }

    return PARSER_OK;
}

int parser_parse_file(Parser *self, BufferView filepath) {
    int result;
    int mapped_file_deinit_result;
    MappedFile mapped_file;
    char *filepath_tmp;

    amal_log_debug("Parsing %.*s", (int)filepath.size, filepath.data);
    assert(!self->started && "Parser can't be reused. Create a new parser.");
    self->started = bool_true;
    /* TODO: Somehow free this... */
    /*return_if_error(scoped_allocator_alloc(self->allocator, filepath.size + 1, (void**)&filepath_tmp));*/
    filepath_tmp = malloc(filepath.size + 1);
    am_memcpy(filepath_tmp, filepath.data, filepath.size);
    filepath_tmp[filepath.size] = '\0';
    result = mapped_file_init(&mapped_file, filepath_tmp, MAPPED_FILE_READ);
    if(result != 0) return result;
    result = parser_parse_buffer(self, create_buffer_view(mapped_file.file_data, mapped_file.file_size), filepath);
    mapped_file_deinit_result = mapped_file_deinit(&mapped_file);
    return result != 0 ? result : mapped_file_deinit_result;
}

/*
Path can be path to included library path (or system library path) in which case
the path separator is a dot, otherwise the path separator is forward slash '/'
*/
int parser_queue_file(Parser *self, BufferView path) {
    /* TODO: Do not load same path twice or the compile will fail (and it can have recursive import) also for performance reasons */
    /* TODO: Parse special path (to include library path with dots) */
    return_if_error(amal_compiler_load_file(self->compiler, path));
    return PARSER_OK;
}