#include "../debug.h"
#include "../line-ed/line-ed.h"
#include "cmd.h"

#include <blue/cmd.h>
#include <blue/term.h>
#include <ivy/lang/ast.h>
#include <ivy/lang/lex.h>
#include <stdbool.h>

enum {
	OPT_SHOW_LEX_TOKENS = 100,
	OPT_SHOW_AST_NODES,
};

struct repl {
	bool r_show_lex, r_show_ast;
};

static void skip_line(struct ivy_lexer *lex)
{
	while (ivy_lexer_tokens_available(lex)) {
		struct ivy_token *tok = ivy_lexer_read(lex);
		bool line_end = (tok->t_type == IVY_TOK_LINEFEED);

		ivy_token_destroy(tok);

		if (line_end) {
			break;
		}
	}
}

static int repl_eval_node(struct repl *repl, struct ivy_ast_node *node)
{
	struct ivy_ast_node_iterator it = {0};

	if (repl->r_show_ast) {
		ivy_ast_node_iterate(
			node, &it, IVY_AST_ITERATE_REGULAR, print_ast_node);
	}

	ivy_ast_node_iterate(node, &it, IVY_AST_ITERATE_POSTORDER, print_ast_node);

	return 0;
}

int repl(const b_command *cmd, const b_arglist *args, const b_array *_)
{
	b_printf(
		"[bold,bright_red]error[[E0384][reset,bold,white]: cannot "
		"assign twice to immutable variable `i`[reset]\n");
	b_printf("[bold,bright_blue] -->[reset] src/main.rs:7:3\n");
	b_printf("[bold,bright_blue]  |[reset]\n");
	b_printf("[bold,bright_blue]4 |[reset]     let i = 0;\n");
	b_printf("[bold,bright_blue]  |         -[reset]\n");
	b_printf("[bold,bright_blue]  |         |[reset]\n");
	b_printf(
		"[bold,bright_blue]  |         first assignment to "
		"`i`[reset]\n");
	b_printf(
		"[bold,bright_blue]  |         help: make this binding "
		"mutable: `mut i`[reset]\n");
	b_printf("[bold,bright_blue]...[reset]\n");
	b_printf("[bold,bright_blue]7 |[reset]     i += 1;\n");
	b_printf(
		"[bold,bright_blue]  |[bold,bright_red]     ^^^^^^ cannot "
		"assign twice to immutable variable[reset]\n");

	struct repl repl = {};
	repl.r_show_lex = b_arglist_get_count(
				  args, OPT_SHOW_LEX_TOKENS, B_COMMAND_INVALID_ID)
	                > 0;
	repl.r_show_ast = b_arglist_get_count(
				  args, OPT_SHOW_AST_NODES, B_COMMAND_INVALID_ID)
	                > 0;

	struct line_ed *ed = line_ed_create();
	line_ed_set_flags(ed, LINE_ED_REMOVE_CONTINUATIONS);

	struct ivy_lexer *lex;
	enum ivy_status status = ivy_lexer_create(&lex);

	if (status != IVY_OK) {
		line_ed_destroy(ed);
		return -1;
	}

	ivy_lexer_set_source(lex, &ed->l_line_source);

	struct ivy_parser *parser;
	status = ivy_parser_create(&parser);

	if (status != IVY_OK) {
		ivy_lexer_destroy(lex);
		line_ed_destroy(ed);
		return -1;
	}

	while (true) {
		struct ivy_token *tok = ivy_lexer_read(lex);
		status = ivy_lexer_get_status(lex);
		if (status == IVY_ERR_EOF) {
			break;
		}

		if (status != IVY_OK) {
			b_err("lex error (%s)",
			      ivy_status_to_string(ivy_lexer_get_status(lex)));
			continue;
		}

		if (repl.r_show_lex) {
			print_lex_token(tok);
		}

		status = ivy_parser_push_token(parser, tok);

		if (status != IVY_OK) {
			b_err("parse error (%s)", ivy_status_to_string(status));
			ivy_token_destroy(tok);
			skip_line(lex);
			continue;
		}

		if (ivy_lexer_tokens_available(lex)) {
			continue;
		}

		struct ivy_ast_node *child = NULL;

		while ((child = ivy_parser_dequeue_node(parser))) {
			repl_eval_node(&repl, child);
			ivy_ast_node_destroy(child);
		}
	}

	ivy_parser_destroy(parser);
	ivy_lexer_destroy(lex);
	line_ed_destroy(ed);
	return 0;
}

B_COMMAND(CMD_REPL, CMD_ROOT)
{
	B_COMMAND_NAME("shell");
	B_COMMAND_SHORT_NAME('S');
	B_COMMAND_DESC("start an interactive Ivy shell.");
	B_COMMAND_HELP_OPTION();
	B_COMMAND_FUNCTION(repl);

	B_COMMAND_OPTION(OPT_SHOW_LEX_TOKENS)
	{
		B_OPTION_LONG_NAME("show-lex");
		B_OPTION_SHORT_NAME('l');
		B_OPTION_DESC(
			"print the lexical tokens generated from the input.");
	}

	B_COMMAND_OPTION(OPT_SHOW_AST_NODES)
	{
		B_OPTION_LONG_NAME("show-ast");
		B_OPTION_SHORT_NAME('a');
		B_OPTION_DESC(
			"print the abstract syntax tree generated from the "
			"input.");
	}
}