/* linenoise.c -- VERSION 1.0
 *
 * Guerrilla line editing library against the idea that a line editing lib
 * needs to be 20,000 lines of C code.
 *
 * You can find the latest source code at:
 *
 *   http://github.com/antirez/linenoise
 *
 * Does a number of crazy assumptions that happen to be true in 99.9999% of
 * the 2010 UNIX computers around.
 *
 * ------------------------------------------------------------------------
 *
 * Copyright (c) 2010-2014, Salvatore Sanfilippo <antirez at gmail dot com>
 * Copyright (c) 2010-2013, Pieter Noordhuis <pcnoordhuis at gmail dot com>
 *
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 *
 *  *  Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *
 *  *  Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * ------------------------------------------------------------------------
 *
 * References:
 * - http://invisible-island.net/xterm/ctlseqs/ctlseqs.html
 * - http://www.3waylabs.com/nw/WWW/products/wizcon/vt220.html
 *
 * Todo list:
 * - Filter bogus Ctrl+<char> combinations.
 * - Win32 support
 *
 * Bloat:
 * - History search like Ctrl+r in readline?
 *
 * List of escape sequences used by this program, we do everything just
 * with three sequences. In order to be so cheap we may have some
 * flickering effect with some slow terminal, but the lesser sequences
 * the more compatible.
 *
 * EL (Erase Line)
 *    Sequence: ESC [ n K
 *    Effect: if n is 0 or missing, clear from cursor to end of line
 *    Effect: if n is 1, clear from beginning of line to cursor
 *    Effect: if n is 2, clear entire line
 *
 * CUF (CUrsor Forward)
 *    Sequence: ESC [ n C
 *    Effect: moves cursor forward n chars
 *
 * CUB (CUrsor Backward)
 *    Sequence: ESC [ n D
 *    Effect: moves cursor backward n chars
 *
 * The following is used to get the terminal width if getting
 * the width with the TIOCGWINSZ ioctl fails
 *
 * DSR (Device Status Report)
 *    Sequence: ESC [ 6 n
 *    Effect: reports the current cusor position as ESC [ n ; m R
 *            where n is the row and m is the column
 *
 * When multi line mode is enabled, we also use an additional escape
 * sequence. However multi line editing is disabled by default.
 *
 * CUU (Cursor Up)
 *    Sequence: ESC [ n A
 *    Effect: moves cursor up of n chars.
 *
 * CUD (Cursor Down)
 *    Sequence: ESC [ n B
 *    Effect: moves cursor down of n chars.
 *
 * When linenoiseClearScreen() is called, two additional escape sequences
 * are used in order to clear the screen and position the cursor at home
 * position.
 *
 * CUP (Cursor position)
 *    Sequence: ESC [ H
 *    Effect: moves the cursor to upper left corner
 *
 * ED (Erase display)
 *    Sequence: ESC [ 2 J
 *    Effect: clear the whole screen
 *
 */

#include "luartos.h"

#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <errno.h>
#include <string.h>
#include <ctype.h>
#include <sys/status.h>
#include <sys/types.h>
#include <sys/list.h>
#include <reent.h>

#include <sys/mount.h>
#include <sys/path.h>
#include <sys/history.h>

#include "linenoise.h"
#include "lua.h"

#define LINENOISE_MAX_LINE LUA_MAXINPUT

/* The linenoiseState structure represents the state during line editing.
 * We pass this state to functions implementing specific editing
 * functionalities. */
struct linenoiseState {
    int ifd;            /* Terminal stdin file descriptor. */
    int ofd;            /* Terminal stdout file descriptor. */
    char *buf;          /* Edited line buffer. */
    size_t buflen;      /* Edited line buffer size. */
    const char *prompt; /* Prompt to display. */
    size_t plen;        /* Prompt length. */
    size_t pos;         /* Current cursor position. */
    size_t oldpos;      /* Previous refresh cursor position. */
    size_t len;         /* Current edited line length. */
    size_t cols;        /* Number of columns in terminal-> */
    size_t maxrows;     /* Maximum num of rows used so far (multiline mode) */
    int history_index;  /* The history index we are currently editing. */
    bool password;      /* A password is being entered. */
};

enum KEY_ACTION{
	KEY_NULL = 0,	    /* NULL */
	CTRL_A = 1,         /* Ctrl+a */
	CTRL_B = 2,         /* Ctrl-b */
	CTRL_C = 3,         /* Ctrl-c */
	CTRL_D = 4,         /* Ctrl-d */
	CTRL_E = 5,         /* Ctrl-e */
	CTRL_F = 6,         /* Ctrl-f */
	CTRL_H = 8,         /* Ctrl-h */
	TAB = 9,            /* Tab */
	CTRL_K = 11,        /* Ctrl+k */
	CTRL_L = 12,        /* Ctrl+l */
	ENTER = 13,         /* Enter */
	CTRL_N = 14,        /* Ctrl-n */
	CTRL_P = 16,        /* Ctrl-p */
	CTRL_T = 20,        /* Ctrl-t */
	CTRL_U = 21,        /* Ctrl+u */
	CTRL_W = 23,        /* Ctrl+w */
	ESC = 27,           /* Escape */
	BACKSPACE =  127    /* Backspace */
};

static void refreshLine(struct linenoiseState *l);

static void linenoiseHistoryAdd(struct linenoiseState *l);
static void linenoiseHistoryGet(struct linenoiseState *l, int up);

/* Debugging macro. */
#if 0
FILE *lndebug_fp = NULL;
#define lndebug(...) \
    do { \
        if (lndebug_fp == NULL) { \
            lndebug_fp = fopen("/tmp/lndebug.txt","a"); \
            fprintf(lndebug_fp, \
            "[%d %d %d] p: %d, rows: %d, rpos: %d, max: %d, oldmax: %d\n", \
            (int)l->len,(int)l->pos,(int)l->oldpos,plen,rows,rpos, \
            (int)l->maxrows,old_rows); \
        } \
        fprintf(lndebug_fp, ", " __VA_ARGS__); \
        fflush(lndebug_fp); \
    } while (0)
#else
#define lndebug(fmt, ...)
#endif

/* ======================= Low level terminal handling ====================== */

/* Clear the screen. Used to handle ctrl+l */
void linenoiseClearScreen(void) {
    if (write(STDOUT_FILENO,"\x1b[H\x1b[2J",7) <= 0) {
        /* nothing to do, just to avoid warning. */
    }
}


/* =========================== Line editing ================================= */

/* We define a very simple "append buffer" structure, that is an heap
 * allocated string where we can append to. This is useful in order to
 * write all the escape sequences in a buffer and flush them to the standard
 * output in a single call, to avoid flickering effects. */
struct abuf {
    char *b;
    int len;
};

static void abInit(struct abuf *ab) {
    ab->b = NULL;
    ab->len = 0;
}

static void abAppend(struct abuf *ab, const char *s, int len) {
    char *new = (ab->b ? realloc(ab->b,ab->len+len) : malloc(ab->len+len));

    if (new == NULL) return;
    memcpy(new+ab->len,s,len);
    ab->b = new;
    ab->len += len;
}

static void abFree(struct abuf *ab) {
    free(ab->b);
}

/* Single line low level line refresh.
 *
 * Rewrite the currently edited line accordingly to the buffer content,
 * cursor position, and number of columns of the terminal. */
static void refreshSingleLine(struct linenoiseState *l) {
    char seq[64];
    size_t plen = strlen(l->prompt);
    int fd = l->ofd;
    char *buf = l->buf;
    size_t len = l->len;
    size_t pos = l->pos;
    struct abuf ab;

    while((plen+pos) >= l->cols) {
        buf++;
        len--;
        pos--;
    }
    while (plen+len > l->cols) {
        len--;
    }

    abInit(&ab);
    /* Cursor to left edge */
    snprintf(seq,64,"\r");
    abAppend(&ab,seq,strlen(seq));
    /* Write the prompt and the current buffer content */
    abAppend(&ab,l->prompt,strlen(l->prompt));
    if (!l->password) {
        abAppend(&ab,buf,len);
    }
    /* Erase to right */
    snprintf(seq,64,"\x1b[0K");
    abAppend(&ab,seq,strlen(seq));
    /* Move cursor to original position. */
    if (!l->password) {
		  snprintf(seq,64,"\r\x1b[%dC", (int)(pos+plen));
		  abAppend(&ab,seq,strlen(seq));
		}
    if (write(fd,ab.b,ab.len) == -1) {} /* Can't recover from write error. */
    abFree(&ab);
}

/* Calls the two low level functions refreshSingleLine() or
 * refreshMultiLine() according to the selected mode. */
static void refreshLine(struct linenoiseState *l) {
	refreshSingleLine(l);
}

/* Insert the character 'c' at cursor current position.
 *
 * On error writing to the terminal -1 is returned, otherwise 0. */
int linenoiseEditInsert(struct linenoiseState *l, char c) {
    if (l->len < l->buflen) {
        if (l->len == l->pos) {
            l->buf[l->pos] = c;
            l->pos++;
            l->len++;
            l->buf[l->len] = '\0';
            if ((l->plen+l->len < l->cols)) {
                /* Avoid a full update of the line in the
                 * trivial case. */
                if (!l->password) {
                    if (write(l->ofd,&c,1) == -1) return -1;
                }
            } else {
                refreshLine(l);
            }
        } else {
            memmove(l->buf+l->pos+1,l->buf+l->pos,l->len-l->pos);
            l->buf[l->pos] = c;
            l->len++;
            l->pos++;
            l->buf[l->len] = '\0';
            refreshLine(l);
        }
    }
    return 0;
}

/* Move cursor on the left. */
void linenoiseEditMoveLeft(struct linenoiseState *l) {
    if (l->pos > 0) {
        l->pos--;
        refreshLine(l);
    }
}

/* Move cursor on the right. */
void linenoiseEditMoveRight(struct linenoiseState *l) {
    if (l->pos != l->len) {
        l->pos++;
        refreshLine(l);
    }
}

/* Move cursor to the start of the line. */
void linenoiseEditMoveHome(struct linenoiseState *l) {
    if (l->pos != 0) {
        l->pos = 0;
        refreshLine(l);
    }
}

/* Move cursor to the end of the line. */
void linenoiseEditMoveEnd(struct linenoiseState *l) {
    if (l->pos != l->len) {
        l->pos = l->len;
        refreshLine(l);
    }
}

/* Delete the character at the right of the cursor without altering the cursor
 * position. Basically this is what happens with the "Delete" keyboard key. */
void linenoiseEditDelete(struct linenoiseState *l) {
    if (l->len > 0 && l->pos < l->len) {
        memmove(l->buf+l->pos,l->buf+l->pos+1,l->len-l->pos-1);
        l->len--;
        l->buf[l->len] = '\0';
        refreshLine(l);
    }
}

/* Backspace implementation. */
void linenoiseEditBackspace(struct linenoiseState *l) {
    if (l->pos > 0 && l->len > 0) {
        memmove(l->buf+l->pos-1,l->buf+l->pos,l->len-l->pos);
        l->pos--;
        l->len--;
        l->buf[l->len] = '\0';
        refreshLine(l);
    }
}

/* Delete the previosu word, maintaining the cursor at the start of the
 * current word. */
void linenoiseEditDeletePrevWord(struct linenoiseState *l) {
    size_t old_pos = l->pos;
    size_t diff;

    while (l->pos > 0 && l->buf[l->pos-1] == ' ')
        l->pos--;
    while (l->pos > 0 && l->buf[l->pos-1] != ' ')
        l->pos--;
    diff = old_pos - l->pos;
    memmove(l->buf+l->pos,l->buf+old_pos,l->len-old_pos+1);
    l->len -= diff;
    refreshLine(l);
}

/* This function is the core of the line editing capability of linenoise.
 * It expects 'fd' to be already in "raw mode" so that every key pressed
 * will be returned ASAP to read().
 *
 * The resulting string is put into 'buf' when the user type enter, or
 * when ctrl+d is typed.
 *
 * The function returns the length of the current buffer. */
static int linenoiseEdit(int stdin_fd, int stdout_fd, char *buf, size_t buflen, const char *prompt, bool password)
{
    struct linenoiseState *l;

    l = malloc(sizeof(struct linenoiseState));
    if (!l) {
    	return 0;
    }

    /* Populate the linenoise state that we pass to functions implementing
     * specific editing functionalities. */
    l->ifd = stdin_fd;
    l->ofd = stdout_fd;
    l->buf = buf;
    l->buflen = buflen;
    l->prompt = prompt;
    l->plen = strlen(prompt);
    l->oldpos = l->pos = 0;
    l->len = 0;
    l->cols = buflen;
    l->maxrows = 0;
    l->history_index = -1;
    l->password = password;

    /* Buffer starts empty. */
    l->buf[0] = '\0';
    l->buflen--; /* Make sure there is always space for the nulterm */

    /* The latest history entry is always our current buffer, that
     * initially is just an empty string. */
        
    if (write(l->ofd,prompt,l->plen) == -1) {
    	free(l);
    	return -1;
    }

    while(1) {
        char c;
        int nread;
        char seq[3];

        nread = read(l->ifd,&c,1);

        if (nread <= 0) {
        	int len = l->len;
        	free(l);
        	return len;
        }

        switch(c) {
        case ENTER:    /* enter */
            if (l->len > 0) {
                if(!l->password) linenoiseHistoryAdd(l);
            }
            
            int len = l->len;
            free(l);
            return (int)len;
        case CTRL_C:     /* ctrl-c */
            errno = EAGAIN;
        	free(l);
            return -1;
        case BACKSPACE:   /* backspace */
        case 8:     /* ctrl-h */
            linenoiseEditBackspace(l);
            break;
        case CTRL_D:     /* ctrl-d, remove char at right of cursor, or if the
                            line is empty, act as end-of-file. */
            if (l->len > 0) {
                linenoiseEditDelete(l);
            } else {
            	free(l);
                return -1;
            }
            break;
        case CTRL_T:    /* ctrl-t, swaps current character with previous. */
            if (l->pos > 0 && l->pos < l->len) {
                int aux = buf[l->pos-1];
                buf[l->pos-1] = buf[l->pos];
                buf[l->pos] = aux;
                if (l->pos != l->len-1) l->pos++;
                refreshLine(l);
            }
            break;
        case CTRL_B:     /* ctrl-b */
            linenoiseEditMoveLeft(l);
            break;
        case CTRL_F:     /* ctrl-f */
            linenoiseEditMoveRight(l);
            break;
        case CTRL_P:    /* ctrl-p */
            break;
        case CTRL_N:    /* ctrl-n */
            break;
        case ESC:    /* escape sequence */
            /* Read the next two bytes representing the escape sequence.
             * Use two calls to handle slow terminals returning the two
             * chars at different times. */
            if (read(l->ifd,seq,1) == -1) break;
            if (read(l->ifd,seq+1,1) == -1) break;

            /* ESC [ sequences. */
            if (seq[0] == '[') {
                if (seq[1] >= '0' && seq[1] <= '9') {
                    /* Extended escape, read additional byte. */
                    if (read(l->ifd,seq+2,1) == -1) break;
                    if (seq[2] == '~') {
                        switch(seq[1]) {
                        case '3': /* Delete key. */
                            linenoiseEditDelete(l);
                            break;
                        }
                    }
                } else {
                    switch(seq[1]) {
                    case 'A': /* Up */
                        linenoiseHistoryGet(l,1);
                        break;
                    case 'B': /* Down */
                        linenoiseHistoryGet(l,0);
                        break;
                    case 'C': /* Right */
                        linenoiseEditMoveRight(l);
                        break;
                    case 'D': /* Left */
                        linenoiseEditMoveLeft(l);
                        break;
                    case 'H': /* Home */
                        linenoiseEditMoveHome(l);
                        break;
                    case 'F': /* End*/
                        linenoiseEditMoveEnd(l);
                        break;
                    }
                }
            }

            /* ESC O sequences. */
            else if (seq[0] == 'O') {
                switch(seq[1]) {
                case 'H': /* Home */
                    linenoiseEditMoveHome(l);
                    break;
                case 'F': /* End*/
                    linenoiseEditMoveEnd(l);
                    break;
                }
            }
            break;
        default:
            if (linenoiseEditInsert(l,c)) {
            	free(l);
            	return -1;
            }
            break;
        case CTRL_U: /* Ctrl+u, delete the whole line. */
            buf[0] = '\0';
            l->pos = l->len = 0;
            refreshLine(l);
            break;
        case CTRL_K: /* Ctrl+k, delete from current to end of line. */
            buf[l->pos] = '\0';
            l->len = l->pos;
            refreshLine(l);
            break;
        case CTRL_A: /* Ctrl+a, go to the start of the line */
            linenoiseEditMoveHome(l);
            break;
        case CTRL_E: /* ctrl+e, go to the end of the line */
            linenoiseEditMoveEnd(l);
            break;
        case CTRL_L: /* ctrl+l, clear screen */
            linenoiseClearScreen();
            refreshLine(l);
            break;
        case CTRL_W: /* ctrl+w, delete previous word */
            linenoiseEditDeletePrevWord(l);
            break;
        }
    }

    int len = l->len;
	free(l);

    return len;
}

/* This function calls the line editing function linenoiseEdit() using
 * the STDIN file descriptor set in raw mode. */
static int linenoiseRaw(char *buf, size_t buflen, const char *prompt, bool password) {
    int count;

    count = linenoiseEdit(fileno(__getreent()->_stdin), fileno(__getreent()->_stdout), buf, buflen, prompt, password);
    printf("\n");

    return count;
}

static void linenoiseHistoryAdd(struct linenoiseState *l) {
    if (!status_get(STATUS_LUA_HISTORY)) return;

    history_add(l->buf);
    
    l->history_index = -1;
}

static void linenoiseHistoryGet(struct linenoiseState *l, int up) {
    if (!status_get(STATUS_LUA_HISTORY)) return;
    
    int res = history_get(l->history_index, up, l->buf, l->cols);
    if (res >= -1) {
        l->history_index = res;
        l->len = strlen(l->buf);
        l->pos = l->len;
    }

    refreshLine(l);
}

void linenoiseHistoryClear() {
    if (status_get(STATUS_LUA_HISTORY)) return;

    char fname[PATH_MAX + 1];

    if (!mount_history_file(fname, sizeof(fname))) {
        return;
    }

    remove(fname);
}

/* The high level function that is the main API of the linenoise library.
 * This function checks if the terminal has basic capabilities, just checking
 * for a blacklist of stupid terminals, and later either calls the line
 * editing function or uses dummy fgets() so that you will be able to type
 * something even in the most desperate of the conditions. */
int linenoisePassword(char *buf, const char *prompt, bool password) {
    int count;
    count = linenoiseRaw(buf,LINENOISE_MAX_LINE,prompt,password);
    if (count == -1) return -1;
    return count;
}

int linenoise(char *buf, const char *prompt) {
    return linenoisePassword(buf, prompt, false);
}