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

#include "array.h"
#include "parser.h"
#include "lexer.h"
#include "string_view.h"

void
parser_init(parser_t *parser, char *file_name)
{
	assert(parser && file_name);
    lexer_init(&parser->lexer, file_name);
}

void
parser_next_expected_token(parser_t *parser, token_t *token, token_kind_t kind)
{
	lexer_next_token(&parser->lexer, token);
	if (token->kind != kind) {
		fprintf(
				stderr,
				"%s:%zu:%zu: parser error: expected token <%s> but got <%s>.\n",
				parser->lexer.file_name,
				token->loc.lineno + 1,
				token->loc.offset - token->loc.lineoffset + 1,
				token_to_cstr(kind),
				token_to_cstr(token->kind));
		exit(EXIT_FAILURE);
	}
}

inst_t *
parser_parse(parser_t *parser) {
	inst_t *insts = array(inst_t);

	token_t token = { 0 };
	int label_count = 0;

	lexer_next_token(&parser->lexer, &token);
	while (token.kind != TOKEN_EOF) {
		switch (token.kind) {
			case TOKEN_KW_PUSH: {
				parser_next_expected_token(parser, &token, TOKEN_NUMBER);

				char value[token.value.size + 1];
				value[token.value.size] = '\0';
				memcpy(value, token.value.chars, token.value.size);

				array_append(insts, ((inst_t) { .type = INST_PUSH, .operand = atoi(value) }));

				parser_next_expected_token(parser, &token, TOKEN_EOS);
				break;
			}
			case TOKEN_KW_ADD: {
				array_append(insts, ((inst_t) { .type = INST_ADD }));
				parser_next_expected_token(parser, &token, TOKEN_EOS);
				break;
			}
			case TOKEN_KW_DUP: {
				array_append(insts, ((inst_t) { .type = INST_DUP }));
				parser_next_expected_token(parser, &token, TOKEN_EOS);
				break;
			}
			case TOKEN_KW_SWAP: {
				array_append(insts, ((inst_t) { .type = INST_SWAP }));
				parser_next_expected_token(parser, &token, TOKEN_EOS);
				break;
			}
			case TOKEN_KW_SUB: {
				array_append(insts, ((inst_t) { .type = INST_SUB }));
				parser_next_expected_token(parser, &token, TOKEN_EOS);
				break;
			}
			case TOKEN_KW_MUL: {
				array_append(insts, ((inst_t) { .type = INST_MUL }));
				parser_next_expected_token(parser, &token, TOKEN_EOS);
				break;
			}
			case TOKEN_KW_STORE: {
				array_append(insts, ((inst_t) { .type = INST_STORE }));
				parser_next_expected_token(parser, &token, TOKEN_EOS);
				break;
			}
			case TOKEN_KW_LOAD: {
				array_append(insts, ((inst_t) { .type = INST_LOAD }));
				parser_next_expected_token(parser, &token, TOKEN_EOS);
				break;
			}
			case TOKEN_KW_RET: {
				array_append(insts, ((inst_t) { .type = INST_RET }));
				parser_next_expected_token(parser, &token, TOKEN_EOS);
				break;
			}
			case TOKEN_IDENT: {
				array_append(insts, ((inst_t) { .type = INST_LABEL, .operand = label_count++ }));
				parser_next_expected_token(parser, &token, TOKEN_COLON);
				parser_next_expected_token(parser, &token, TOKEN_EOS);
				break;
			}
			case TOKEN_KW_JMP: {
				parser_next_expected_token(parser, &token, TOKEN_NUMBER);

				char value[token.value.size + 1];
				value[token.value.size] = '\0';
				memcpy(value, token.value.chars, token.value.size);

				array_append(insts, ((inst_t) { .type = INST_JMP, .operand = atoi(value) }));

				parser_next_expected_token(parser, &token, TOKEN_EOS);
				break;
			}
			case TOKEN_KW_JMPZ: {
				parser_next_expected_token(parser, &token, TOKEN_NUMBER);

				char value[token.value.size + 1];
				value[token.value.size] = '\0';
				memcpy(value, token.value.chars, token.value.size);

				array_append(insts, ((inst_t) { .type = INST_JMPZ, .operand = atoi(value) }));

				parser_next_expected_token(parser, &token, TOKEN_EOS);
				break;
			}
			case TOKEN_KW_CALL: {
				parser_next_expected_token(parser, &token, TOKEN_NUMBER);

				char value[token.value.size + 1];
				value[token.value.size] = '\0';
				memcpy(value, token.value.chars, token.value.size);

				array_append(insts, ((inst_t) { .type = INST_CALL, .operand = atoi(value) }));

				parser_next_expected_token(parser, &token, TOKEN_EOS);
				break;
			}
			case TOKEN_KW_READI: {
				array_append(insts, ((inst_t) { .type = INST_READI }));
				parser_next_expected_token(parser, &token, TOKEN_EOS);
				break;
			}
			case TOKEN_KW_READC: {
				array_append(insts, ((inst_t) { .type = INST_READC }));
				parser_next_expected_token(parser, &token, TOKEN_EOS);
				break;
			}
			case TOKEN_KW_PRINTI: {
				array_append(insts, ((inst_t) { .type = INST_PRINTI }));
				parser_next_expected_token(parser, &token, TOKEN_EOS);
				break;
			}
			case TOKEN_KW_PRINTC: {
				array_append(insts, ((inst_t) { .type = INST_PRINTC }));
				parser_next_expected_token(parser, &token, TOKEN_EOS);
				break;
			}
			case TOKEN_KW_END: {
				array_append(insts, ((inst_t) { .type = INST_END }));
				parser_next_expected_token(parser, &token, TOKEN_EOS);
				break;
			}
			case TOKEN_EOS: {
				break;
			}
			default: break;
		}
		lexer_next_token(&parser->lexer, &token);
	}

	return insts;
}