/*
 * This file is part of the MicroPython project, http://micropython.org/
 *
 * The MIT License (MIT)
 *
 * Copyright (c) 2013, 2014 Damien P. George
 * Copyright (c) Quectel Wireless Solution, Co., Ltd.All Rights Reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */

#include <stdio.h>
#include <stdint.h>
#include <string.h>

#include "py/mpstate.h"
#include "py/repl.h"
#include "py/mphal.h"
#include "lib/mp-readline/readline.h"

#if 0 // print debugging info
#define DEBUG_PRINT (1)
#define DEBUG_printf printf
#else // don't print debugging info
#define DEBUG_printf(...) (void)0
#endif

#define READLINE_HIST_SIZE (MP_ARRAY_SIZE(MP_STATE_PORT(readline_hist)))

enum { ESEQ_NONE, ESEQ_ESC, ESEQ_ESC_BRACKET, ESEQ_ESC_BRACKET_DIGIT, ESEQ_ESC_O };

void readline_init0(void) {
 memset(MP_STATE_PORT(readline_hist), 0, READLINE_HIST_SIZE * sizeof(const char*));
}

STATIC char *str_dup_maybe(const char *str) {
 uint32_t len = strlen(str);
 char *s2 = m_new_maybe(char, len + 1);
 if (s2 == NULL) {
 return NULL;
 }
 memcpy(s2, str, len + 1);
 return s2;
}

// By default assume terminal which implements VT100 commands...
#ifndef MICROPY_HAL_HAS_VT100
#define MICROPY_HAL_HAS_VT100 (1)
#endif

// ...and provide the implementation using them
#if MICROPY_HAL_HAS_VT100
STATIC void mp_hal_move_cursor_back(uint pos) {
 if (pos <= 4) {
 // fast path for most common case of 1 step back
 mp_hal_stdout_tx_strn("\b\b\b\b", pos);
 } else {
 char vt100_command[6];
 // snprintf needs space for the terminating null character
 int n = snprintf(&vt100_command[0], sizeof(vt100_command), "\x1b[%u", pos);
 if (n > 0) {
 assert((unsigned)n < sizeof(vt100_command));
 vt100_command[n] = 'D'; // replace null char
 mp_hal_stdout_tx_strn(vt100_command, n + 1);
 }
 }
}

STATIC void mp_hal_erase_line_from_cursor(uint n_chars_to_erase) {
 (void)n_chars_to_erase;
 mp_hal_stdout_tx_strn("\x1b[K", 3);
}
#endif

typedef struct _readline_t {
 vstr_t *line;
 size_t orig_line_len;
 int escape_seq;
 int hist_cur;
 size_t cursor_pos;
 char escape_seq_buf[1];
 const char *prompt;
} readline_t;

STATIC readline_t rl;

#if MICROPY_REPL_EMACS_WORDS_MOVE
STATIC size_t cursor_count_word(int forward) {
 const char *line_buf = vstr_str(rl.line);
 size_t pos = rl.cursor_pos;
 bool in_word = false;

 for (;;) {
 // if moving backwards and we've reached 0... break
 if (!forward && pos == 0) {
 break;
 }
 // or if moving forwards and we've reached to the end of line... break
 else if (forward && pos == vstr_len(rl.line)) {
 break;
 }

 if (unichar_isalnum(line_buf[pos + (forward - 1)])) {
 in_word = true;
 } else if (in_word) {
 break;
 }

 pos += forward ? forward : -1;
 }

 return forward ? pos - rl.cursor_pos : rl.cursor_pos - pos;
}
#endif

int readline_process_char(int c) {
 size_t last_line_len = rl.line->len;
 int redraw_step_back = 0;
 bool redraw_from_cursor = false;
 int redraw_step_forward = 0;
 if (rl.escape_seq == ESEQ_NONE) {
 if (CHAR_CTRL_A <= c && c <= CHAR_CTRL_E && vstr_len(rl.line) == rl.orig_line_len) {
 // control character with empty line
 return c;
 } else if (c == CHAR_CTRL_A) {
 // CTRL-A with non-empty line is go-to-start-of-line
 goto home_key;
 #if MICROPY_REPL_EMACS_KEYS
 } else if (c == CHAR_CTRL_B) {
 // CTRL-B with non-empty line is go-back-one-char
 goto left_arrow_key;
 #endif
 } else if (c == CHAR_CTRL_C) {
 // CTRL-C with non-empty line is cancel
 return c;
 #if MICROPY_REPL_EMACS_KEYS
 } else if (c == CHAR_CTRL_D) {
 // CTRL-D with non-empty line is delete-at-cursor
 goto delete_key;
 #endif
 } else if (c == CHAR_CTRL_E) {
 // CTRL-E is go-to-end-of-line
 goto end_key;
 #if MICROPY_REPL_EMACS_KEYS
 } else if (c == CHAR_CTRL_F) {
 // CTRL-F with non-empty line is go-forward-one-char
 goto right_arrow_key;
 } else if (c == CHAR_CTRL_K) {
 // CTRL-K is kill from cursor to end-of-line, inclusive
 vstr_cut_tail_bytes(rl.line, last_line_len - rl.cursor_pos);
 // set redraw parameters
 redraw_from_cursor = true;
 } else if (c == CHAR_CTRL_N) {
 // CTRL-N is go to next line in history
 goto down_arrow_key;
 } else if (c == CHAR_CTRL_P) {
 // CTRL-P is go to previous line in history
 goto up_arrow_key;
 } else if (c == CHAR_CTRL_U) {
 // CTRL-U is kill from beginning-of-line up to cursor
 vstr_cut_out_bytes(rl.line, rl.orig_line_len, rl.cursor_pos - rl.orig_line_len);
 // set redraw parameters
 redraw_step_back = rl.cursor_pos - rl.orig_line_len;
 redraw_from_cursor = true;
 #endif
 #if MICROPY_REPL_EMACS_EXTRA_WORDS_MOVE
 } else if (c == CHAR_CTRL_W) {
 goto backward_kill_word;
 #endif
 } else if (c == '\r') {
 // newline
 mp_hal_stdout_tx_str("\r\n");
 readline_push_history(vstr_null_terminated_str(rl.line) + rl.orig_line_len);
 return 0;
 } else if (c == 27) {
 // escape sequence
 rl.escape_seq = ESEQ_ESC;
 } else if (c == 8 || c == 127) {
 // backspace/delete
 if (rl.cursor_pos > rl.orig_line_len) {
 // work out how many chars to backspace
 #if MICROPY_REPL_AUTO_INDENT
 int nspace = 0;
 for (size_t i = rl.orig_line_len; i < rl.cursor_pos; i++) {
 if (rl.line->buf[i] != ' ') {
 nspace = 0;
 break;
 }
 nspace += 1;
 }
 if (nspace < 4) {
 nspace = 1;
 } else {
 nspace = 4;
 }
 #else
 int nspace = 1;
 #endif

 // do the backspace
 vstr_cut_out_bytes(rl.line, rl.cursor_pos - nspace, nspace);
 // set redraw parameters
 redraw_step_back = nspace;
 redraw_from_cursor = true;
 }
 #if MICROPY_HELPER_REPL
 } else if (c == 9) {
 // tab magic
 const char *compl_str;
 size_t compl_len = mp_repl_autocomplete(rl.line->buf + rl.orig_line_len, rl.cursor_pos - rl.orig_line_len, &mp_plat_print, &compl_str);
 if (compl_len == 0) {
 // no match
 } else if (compl_len == (size_t)(-1)) {
 // many matches
 mp_hal_stdout_tx_str(rl.prompt);
 mp_hal_stdout_tx_strn(rl.line->buf + rl.orig_line_len, rl.cursor_pos - rl.orig_line_len);
 redraw_from_cursor = true;
 } else {
 // one match
 for (size_t i = 0; i < compl_len; ++i) {
 vstr_ins_byte(rl.line, rl.cursor_pos + i, *compl_str++);
 }
 // set redraw parameters
 redraw_from_cursor = true;
 redraw_step_forward = compl_len;
 }
 #endif
 } else if (32 <= c && c <= 126) {
 // printable character
 vstr_ins_char(rl.line, rl.cursor_pos, c);
 // set redraw parameters
 redraw_from_cursor = true;
 redraw_step_forward = 1;
 }
 } else if (rl.escape_seq == ESEQ_ESC) {
 switch (c) {
 case '[':
 rl.escape_seq = ESEQ_ESC_BRACKET;
 break;
 case 'O':
 rl.escape_seq = ESEQ_ESC_O;
 break;
 #if MICROPY_REPL_EMACS_WORDS_MOVE
 case 'b':
#if MICROPY_REPL_EMACS_EXTRA_WORDS_MOVE
backward_word:
#endif
 redraw_step_back = cursor_count_word(0);
 rl.escape_seq = ESEQ_NONE;
 break;
 case 'f':
#if MICROPY_REPL_EMACS_EXTRA_WORDS_MOVE
forward_word:
#endif
 redraw_step_forward = cursor_count_word(1);
 rl.escape_seq = ESEQ_NONE;
 break;
 case 'd':
 vstr_cut_out_bytes(rl.line, rl.cursor_pos, cursor_count_word(1));
 redraw_from_cursor = true;
 rl.escape_seq = ESEQ_NONE;
 break;
 case 127:
#if MICROPY_REPL_EMACS_EXTRA_WORDS_MOVE
backward_kill_word:
#endif
 redraw_step_back = cursor_count_word(0);
 vstr_cut_out_bytes(rl.line, rl.cursor_pos - redraw_step_back, redraw_step_back);
 redraw_from_cursor = true;
 rl.escape_seq = ESEQ_NONE;
 break;
 #endif
 default:
 DEBUG_printf("(ESC %d)", c);
 rl.escape_seq = ESEQ_NONE;
 break;
 }
 } else if (rl.escape_seq == ESEQ_ESC_BRACKET) {
 if ('0' <= c && c <= '9') {
 rl.escape_seq = ESEQ_ESC_BRACKET_DIGIT;
 rl.escape_seq_buf[0] = c;
 } else {
 rl.escape_seq = ESEQ_NONE;
 if (c == 'A') {
#if MICROPY_REPL_EMACS_KEYS
up_arrow_key:
#endif
 // up arrow
 if (rl.hist_cur + 1 < (int)READLINE_HIST_SIZE && MP_STATE_PORT(readline_hist)[rl.hist_cur + 1] != NULL) {
 // increase hist num
 rl.hist_cur += 1;
 // set line to history
 rl.line->len = rl.orig_line_len;
 vstr_add_str(rl.line, MP_STATE_PORT(readline_hist)[rl.hist_cur]);
 // set redraw parameters
 redraw_step_back = rl.cursor_pos - rl.orig_line_len;
 redraw_from_cursor = true;
 redraw_step_forward = rl.line->len - rl.orig_line_len;
 }
 } else if (c == 'B') {
#if MICROPY_REPL_EMACS_KEYS
down_arrow_key:
#endif
 // down arrow
 if (rl.hist_cur >= 0) {
 // decrease hist num
 rl.hist_cur -= 1;
 // set line to history
 vstr_cut_tail_bytes(rl.line, rl.line->len - rl.orig_line_len);
 if (rl.hist_cur >= 0) {
 vstr_add_str(rl.line, MP_STATE_PORT(readline_hist)[rl.hist_cur]);
 }
 // set redraw parameters
 redraw_step_back = rl.cursor_pos - rl.orig_line_len;
 redraw_from_cursor = true;
 redraw_step_forward = rl.line->len - rl.orig_line_len;
 }
 } else if (c == 'C') {
#if MICROPY_REPL_EMACS_KEYS
right_arrow_key:
#endif
 // right arrow
 if (rl.cursor_pos < rl.line->len) {
 redraw_step_forward = 1;
 }
 } else if (c == 'D') {
#if MICROPY_REPL_EMACS_KEYS
left_arrow_key:
#endif
 // left arrow
 if (rl.cursor_pos > rl.orig_line_len) {
 redraw_step_back = 1;
 }
 } else if (c == 'H') {
 // home
 goto home_key;
 } else if (c == 'F') {
 // end
 goto end_key;
 } else {
 DEBUG_printf("(ESC [ %d)", c);
 }
 }
 } else if (rl.escape_seq == ESEQ_ESC_BRACKET_DIGIT) {
 if (c == '~') {
 if (rl.escape_seq_buf[0] == '1' || rl.escape_seq_buf[0] == '7') {
home_key:
 redraw_step_back = rl.cursor_pos - rl.orig_line_len;
 } else if (rl.escape_seq_buf[0] == '4' || rl.escape_seq_buf[0] == '8') {
end_key:
 redraw_step_forward = rl.line->len - rl.cursor_pos;
 } else if (rl.escape_seq_buf[0] == '3') {
 // delete
#if MICROPY_REPL_EMACS_KEYS
delete_key:
#endif
 if (rl.cursor_pos < rl.line->len) {
 vstr_cut_out_bytes(rl.line, rl.cursor_pos, 1);
 redraw_from_cursor = true;
 }
 } else {
 DEBUG_printf("(ESC [ %c %d)", rl.escape_seq_buf[0], c);
 }
 #if MICROPY_REPL_EMACS_EXTRA_WORDS_MOVE
 } else if (c == ';' && rl.escape_seq_buf[0] == '1') {
 // ';' is used to separate parameters. so first parameter was '1',
 // that's used for sequences like ctrl+left, which we will try to parse.
 // escape_seq state is reset back to ESEQ_ESC_BRACKET, as if we've just received
 // the opening bracket, because more parameters are to come.
 // we don't track the parameters themselves to keep low on logic and code size. that
 // might be required in the future if more complex sequences are added.
 rl.escape_seq = ESEQ_ESC_BRACKET;
 // goto away from the state-machine, as rl.escape_seq will be overridden.
 goto redraw;
 } else if (rl.escape_seq_buf[0] == '5' && c == 'C') {
 // ctrl+right
 goto forward_word;
 } else if (rl.escape_seq_buf[0] == '5' && c == 'D') {
 // ctrl+left
 goto backward_word;
 #endif
 } else {
 DEBUG_printf("(ESC [ %c %d)", rl.escape_seq_buf[0], c);
 }
 rl.escape_seq = ESEQ_NONE;
 } else if (rl.escape_seq == ESEQ_ESC_O) {
 switch (c) {
 case 'H':
 goto home_key;
 case 'F':
 goto end_key;
 default:
 DEBUG_printf("(ESC O %d)", c);
 rl.escape_seq = ESEQ_NONE;
 }
 } else {
 rl.escape_seq = ESEQ_NONE;
 }

#if MICROPY_REPL_EMACS_EXTRA_WORDS_MOVE
redraw:
#endif

 // redraw command prompt, efficiently
 if (redraw_step_back > 0) {
 mp_hal_move_cursor_back(redraw_step_back);
 rl.cursor_pos -= redraw_step_back;
 }
 if (redraw_from_cursor) {
 if (rl.line->len < last_line_len) {
 // erase old chars
 mp_hal_erase_line_from_cursor(last_line_len - rl.cursor_pos);
 }
 // draw new chars
 mp_hal_stdout_tx_strn(rl.line->buf + rl.cursor_pos, rl.line->len - rl.cursor_pos);
 // move cursor forward if needed (already moved forward by length of line, so move it back)
 mp_hal_move_cursor_back(rl.line->len - (rl.cursor_pos + redraw_step_forward));
 rl.cursor_pos += redraw_step_forward;
 } else if (redraw_step_forward > 0) {
 // draw over old chars to move cursor forwards
 mp_hal_stdout_tx_strn(rl.line->buf + rl.cursor_pos, redraw_step_forward);
 rl.cursor_pos += redraw_step_forward;
 }

 return -1;
}

#if MICROPY_REPL_AUTO_INDENT
STATIC void readline_auto_indent(void) {
 vstr_t *line = rl.line;
 if (line->len > 1 && line->buf[line->len - 1] == '\n') {
 int i;
 for (i = line->len - 1; i > 0; i--) {
 if (line->buf[i - 1] == '\n') {
 break;
 }
 }
 size_t j;
 for (j = i; j < line->len; j++) {
 if (line->buf[j] != ' ') {
 break;
 }
 }
 // i=start of line; j=first non-space
 if (i > 0 && j + 1 == line->len) {
 // previous line is not first line and is all spaces
 for (size_t k = i - 1; k > 0; --k) {
 if (line->buf[k - 1] == '\n') {
 // don't auto-indent if last 2 lines are all spaces
 return;
 } else if (line->buf[k - 1] != ' ') {
 // 2nd previous line is not all spaces
 break;
 }
 }
 }
 int n = (j - i) / 4;
 if (line->buf[line->len - 2] == ':') {
 n += 1;
 }
 while (n-- > 0) {
 vstr_add_strn(line, " ", 4);
 mp_hal_stdout_tx_strn(" ", 4);
 rl.cursor_pos += 4;
 }
 }
}
#endif

void readline_note_newline(const char *prompt) {
 rl.orig_line_len = rl.line->len;
 rl.cursor_pos = rl.orig_line_len;
 rl.prompt = prompt;
 mp_hal_stdout_tx_str(prompt);
 #if MICROPY_REPL_AUTO_INDENT
 readline_auto_indent();
 #endif
}

void readline_init(vstr_t *line, const char *prompt) {
 rl.line = line;
 rl.orig_line_len = line->len;
 rl.escape_seq = ESEQ_NONE;
 rl.escape_seq_buf[0] = 0;
 rl.hist_cur = -1;
 rl.cursor_pos = rl.orig_line_len;
 rl.prompt = prompt;
 mp_hal_stdout_tx_str(prompt);
 #if MICROPY_REPL_AUTO_INDENT
 readline_auto_indent();
 #endif
}

int readline(vstr_t *line, const char *prompt) {
 readline_init(line, prompt);
 for (;;) {
 int c = mp_hal_stdin_rx_chr();
 int r = readline_process_char(c);
 if (r >= 0) {
 return r;
 }
 }
}

void readline_push_history(const char *line) {
 if (line[0] != '0円'
 && (MP_STATE_PORT(readline_hist)[0] == NULL
 || strcmp(MP_STATE_PORT(readline_hist)[0], line) != 0)) {
 // a line which is not empty and different from the last one
 // so update the history
 char *most_recent_hist = str_dup_maybe(line);
 if (most_recent_hist != NULL) {
 for (int i = READLINE_HIST_SIZE - 1; i > 0; i--) {
 MP_STATE_PORT(readline_hist)[i] = MP_STATE_PORT(readline_hist)[i - 1];
 }
 MP_STATE_PORT(readline_hist)[0] = most_recent_hist;
 }
 }
}