#include "line-ed.h"

#include "history.h"
#include "hook.h"
#include "input.h"
#include "prompt.h"

#include <ctype.h>
#include <fx/stream.h>
#include <fx/term/tty.h>
#include <fx/wstr.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <wchar.h>
#include <wctype.h>

struct line_ed *line_ed_create(void)
{
	struct line_ed *out = malloc(sizeof *out);
	if (!out) {
		return NULL;
	}

	memset(out, 0x0, sizeof *out);

	out->l_buf = malloc(LINE_MAX);
	if (!out->l_buf) {
		free(out);
		return NULL;
	}

	out->l_history = fx_array_create();
	if (!out->l_history) {
		free(out->l_buf);
		free(out);
		return NULL;
	}

	pthread_mutex_init(&out->l_lock, NULL);
	out->l_tty = fx_stdtty;
	out->l_buf_end = out->l_buf + LINE_MAX;
	out->l_buf_ptr = out->l_buf;
	out->l_line_end = out->l_buf;

	out->l_prompt[PROMPT_MAIN] = ">>> ";
	out->l_prompt[PROMPT_CONT] = "> ";

	return out;
}

void line_ed_destroy(struct line_ed *ed)
{
	fx_array_unref(ed->l_history);
	free(ed->l_buf);
	free(ed);
}

void line_ed_set_flags(struct line_ed *ed, enum line_ed_flags flags)
{
	ed->l_flags |= flags;
}

void line_ed_set_scope_type(struct line_ed *ed, const char *scope_type)
{
	ed->l_scope_type = scope_type;
}

static void clear_buffer(struct line_ed *ed)
{
	memset(ed->l_buf, 0x0, ed->l_buf_end - ed->l_buf);

	ed->l_buf_ptr = ed->l_buf;
	ed->l_line_end = ed->l_buf;

	ed->l_cursor_x = 0;
	ed->l_cursor_y = 0;

	ed->l_continuations = 0;
}

static void convert_continuation_feeds(fx_wchar *s, size_t max)
{
	fx_wchar *end = s + max;
	size_t len = fx_wstrlen(s);

	while (1) {
		size_t r = fx_wstrcspn(s, L"\\");
		if (s + r > end) {
			break;
		}

		s += r;
		len -= r;

		if (*s == '\0') {
			break;
		}

		if (*(s + 1) != '\n') {
			s++;
			continue;
		}

		memmove(s, s + 1, len);
		s += 1;
	}
}

static void remove_continuation_feeds(fx_wchar *s, size_t max)
{
	fx_wchar *end = s + max;
	size_t len = fx_wstrlen(s);

	while (1) {
		size_t r = fx_wstrcspn(s, L"\\");
		if (s + r > end) {
			break;
		}

		s += r;
		len -= r;

		if (*s == '\0') {
			break;
		}

		if (*(s + 1) != '\n') {
			s++;
			continue;
		}

		memmove(s, s + 2, len);
		s += 2;
	}
}

static bool input_is_empty(struct line_ed *ed)
{
	const fx_wchar *p = ed->l_buf;
	while (p < ed->l_line_end) {
		if (!fx_wchar_is_space(*p)) {
			return false;
		}
	}

	return true;
}

static void check_suspended(struct line_ed *ed)
{
	pthread_mutex_lock(&ed->l_lock);
	while (1) {
		if (!ed->l_suspended) {
			break;
		}
		pthread_cond_wait(&ed->l_suspended_cond, &ed->l_lock);
	}

	pthread_mutex_unlock(&ed->l_lock);
}

size_t line_ed_readline(struct line_ed *ed, fx_stringstream *out)
{
	clear_buffer(ed);

	bool append_history = false;
	size_t append_to_index = (size_t)-1;
	if (!ed->l_scope_type) {
		alloc_empty_history_entry(ed);
	} else {
		append_history = true;
		append_to_index = ed->l_history_pos;
	}

	fx_tty *tty = ed->l_tty;
	fx_tty_set_mode(tty, FX_TTY_RAW);
	show_prompt(ed);

	for (int i = 0; ed->l_buf[i]; i++) {
		if (ed->l_buf[i] == '\n') {
			fputc('\r', stdout);
		}

		fx_stream_write_char(fx_stdout, ed->l_buf[i]);
	}
	fflush(stdout);

	bool end = false;
	bool eof = false;

	while (!end) {
		check_suspended(ed);

		fx_keycode key = fx_tty_read_key(tty);
		hook_keypress(ed, key);

		if (ed->l_suspended) {
			continue;
		}

		if (key == FX_TTY_CTRL_KEY('d')) {
			if (!input_is_empty(ed)) {
				continue;
			}

			eof = true;
			break;
		}

		if (key & FX_MOD_CTRL) {
			continue;
		}

		switch (key) {
		case FX_KEY_RETURN:
			fx_tty_reset_vmode(tty);
			if (ed->l_line_end > ed->l_buf
			    && *(ed->l_line_end - 1) != '\\') {
				end = true;
				break;
			}

			if (input_is_empty(ed)) {
				fputc('\r', stdout);
				fputc('\n', stdout);
				clear_buffer(ed);
				show_prompt(ed);
				break;
			}

			*ed->l_line_end = '\n';
			ed->l_line_end++;
			ed->l_buf_ptr = ed->l_line_end;

			ed->l_cursor_x = 0;
			ed->l_cursor_y++;
			ed->l_continuations++;
			fputc('\r', stdout);
			fputc('\n', stdout);
			// fputs("\033[G\n", stdout);
			show_prompt(ed);
			break;
		case FX_KEY_BACKSPACE:
			backspace(ed);
			break;
		case FX_KEY_ARROW_LEFT:
			cursor_left(ed);
			break;
		case FX_KEY_ARROW_RIGHT:
			cursor_right(ed);
			break;
		case FX_KEY_ARROW_UP:
			arrow_up(ed);
			break;
		case FX_KEY_ARROW_DOWN:
			arrow_down(ed);
			break;
		default:
			if (fx_wchar_is_graph(key) || key == ' ') {
				put_char(ed, key);
			}
			break;
		}
	}

	fx_tty_set_mode(tty, FX_TTY_CANONICAL);
	fputc('\n', stdout);

	if (*ed->l_buf == '\0') {
		return eof ? -1 : 0;
	}

	if (append_history) {
		ed->l_history_pos = append_to_index;
		append_buf_to_history(ed);
	} else {
		ed->l_history_pos = fx_array_get_size(ed->l_history) - 1;

		const char *last = last_history_line(ed);
		if (!last || fx_wastrcmp(last, ed->l_buf) != 0) {
			save_buf_to_history(ed);
		}
	}

	size_t sz = ed->l_line_end - ed->l_buf + 1;

	if ((ed->l_flags & LINE_ED_REMOVE_CONTINUATIONS)
	    == LINE_ED_REMOVE_CONTINUATIONS) {
		remove_continuation_feeds(ed->l_buf, sz);
	} else if (
		(ed->l_flags & LINE_ED_CONVERT_CONTINUATIONS)
		== LINE_ED_CONVERT_CONTINUATIONS) {
		convert_continuation_feeds(ed->l_buf, sz);
	}

	fx_stream_write_wstr(out, ed->l_buf, NULL);

	if (!(ed->l_flags & LINE_ED_NO_TRAILING_LINEFEED)) {
		fx_stream_write_char(out, '\n');
	}

	return sz;
}

int line_ed_suspend(struct line_ed *ed)
{
	pthread_mutex_lock(&ed->l_lock);
	ed->l_suspended = true;
	pthread_cond_signal(&ed->l_suspended_cond);
	fx_tty_clear(ed->l_tty, FX_TTY_CLEAR_LINE | FX_TTY_CLEAR_ALL);
	fx_tty_set_mode(ed->l_tty, FX_TTY_CANONICAL);
	fx_tty_move_cursor_x(ed->l_tty, FX_TTY_POS_START, 0);
	pthread_mutex_unlock(&ed->l_lock);

	return 0;
}

int line_ed_resume(struct line_ed *ed)
{
	pthread_mutex_lock(&ed->l_lock);
	fx_tty_set_mode(ed->l_tty, FX_TTY_RAW);
	fx_tty_clear(ed->l_tty, FX_TTY_CLEAR_LINE | FX_TTY_CLEAR_ALL);
	show_prompt(ed);

	size_t prompt_len = 0;
	if (ed->l_cursor_y == 0) {
		prompt_len = prompt_length(ed, PROMPT_MAIN);
	}

	size_t x = 0;
	for (int i = 0; ed->l_buf[i]; i++) {
		if (ed->l_buf[i] == '\n') {
			fputc('\r', stdout);
		}

		fx_stream_write_char(fx_stdout, ed->l_buf[i]);
		x++;
	}

	fflush(stdout);
	fx_tty_move_cursor_x(ed->l_tty, FX_TTY_POS_START, prompt_len + x);
	ed->l_suspended = false;
	pthread_cond_signal(&ed->l_suspended_cond);
	pthread_mutex_unlock(&ed->l_lock);

	return 0;
}