/*
 * This file is part of the MicroPython project, http://micropython.org/
 *
 * The MIT License (MIT)
 *
 * Copyright (c) 2013-2015 Damien P. George
 *
 * 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 <string.h>
#include "py/obj.h"
#include "py/runtime.h"
#include "py/builtin.h"
#include "py/repl.h"

#if MICROPY_HELPER_REPL

STATIC bool str_startswith_word(const char *str, const char *head) {
    size_t i;
    for (i = 0; str[i] && head[i]; i++) {
        if (str[i] != head[i]) {
            return false;
        }
    }
    return head[i] == '\0' && (str[i] == '\0' || !unichar_isident(str[i]));
}

bool mp_repl_continue_with_input(const char *input) {
    // check for blank input
    if (input[0] == '\0') {
        return false;
    }

    // check if input starts with a certain keyword
    bool starts_with_compound_keyword =
           input[0] == '@'
        || str_startswith_word(input, "if")
        || str_startswith_word(input, "while")
        || str_startswith_word(input, "for")
        || str_startswith_word(input, "try")
        || str_startswith_word(input, "with")
        || str_startswith_word(input, "def")
        || str_startswith_word(input, "class")
        #if MICROPY_PY_ASYNC_AWAIT
        || str_startswith_word(input, "async")
        #endif
        ;

    // check for unmatched open bracket, quote or escape quote
    #define Q_NONE (0)
    #define Q_1_SINGLE (1)
    #define Q_1_DOUBLE (2)
    #define Q_3_SINGLE (3)
    #define Q_3_DOUBLE (4)
    int n_paren = 0;
    int n_brack = 0;
    int n_brace = 0;
    int in_quote = Q_NONE;
    const char *i;
    for (i = input; *i; i++) {
        if (*i == '\'') {
            if ((in_quote == Q_NONE || in_quote == Q_3_SINGLE) && i[1] == '\'' && i[2] == '\'') {
                i += 2;
                in_quote = Q_3_SINGLE - in_quote;
            } else if (in_quote == Q_NONE || in_quote == Q_1_SINGLE) {
                in_quote = Q_1_SINGLE - in_quote;
            }
        } else if (*i == '"') {
            if ((in_quote == Q_NONE || in_quote == Q_3_DOUBLE) && i[1] == '"' && i[2] == '"') {
                i += 2;
                in_quote = Q_3_DOUBLE - in_quote;
            } else if (in_quote == Q_NONE || in_quote == Q_1_DOUBLE) {
                in_quote = Q_1_DOUBLE - in_quote;
            }
        } else if (*i == '\\' && (i[1] == '\'' || i[1] == '"' || i[1] == '\\')) {
            if (in_quote != Q_NONE) {
                i++;
            }
        } else if (in_quote == Q_NONE) {
            switch (*i) {
                case '(': n_paren += 1; break;
                case ')': n_paren -= 1; break;
                case '[': n_brack += 1; break;
                case ']': n_brack -= 1; break;
                case '{': n_brace += 1; break;
                case '}': n_brace -= 1; break;
                default: break;
            }
        }
    }

    // continue if unmatched brackets or quotes
    if (n_paren > 0 || n_brack > 0 || n_brace > 0 || in_quote == Q_3_SINGLE || in_quote == Q_3_DOUBLE) {
        return true;
    }

    // continue if last character was backslash (for line continuation)
    if (i[-1] == '\\') {
        return true;
    }

    // continue if compound keyword and last line was not empty
    if (starts_with_compound_keyword && i[-1] != '\n') {
        return true;
    }

    // otherwise, don't continue
    return false;
}

size_t mp_repl_autocomplete(const char *str, size_t len, const mp_print_t *print, const char **compl_str) {
    // scan backwards to find start of "a.b.c" chain
    const char *org_str = str;
    const char *top = str + len;
    for (const char *s = top; --s >= str;) {
        if (!(unichar_isalpha(*s) || unichar_isdigit(*s) || *s == '_' || *s == '.')) {
            ++s;
            str = s;
            break;
        }
    }

    size_t nqstr = QSTR_TOTAL();

    // begin search in outer global dict which is accessed from __main__
    mp_obj_t obj = MP_OBJ_FROM_PTR(&mp_module___main__);
    mp_obj_t dest[2];

    for (;;) {
        // get next word in string to complete
        const char *s_start = str;
        while (str < top && *str != '.') {
            ++str;
        }
        size_t s_len = str - s_start;

        if (str < top) {
            // a complete word, lookup in current object
            qstr q = qstr_find_strn(s_start, s_len);
            if (q == MP_QSTR_NULL) {
                // lookup will fail
                return 0;
            }
            mp_load_method_protected(obj, q, dest, true);
            obj = dest[0]; // attribute, method, or MP_OBJ_NULL if nothing found

            if (obj == MP_OBJ_NULL) {
                // lookup failed
                return 0;
            }

            // skip '.' to move to next word
            ++str;

        } else {
            // end of string, do completion on this partial name

            // look for matches
            const char *match_str = NULL;
            size_t match_len = 0;
            qstr q_first = 0, q_last = 0;
            for (qstr q = MP_QSTR_ + 1; q < nqstr; ++q) {
                size_t d_len;
                const char *d_str = (const char*)qstr_data(q, &d_len);
                if (s_len <= d_len && strncmp(s_start, d_str, s_len) == 0) {
                    mp_load_method_protected(obj, q, dest, true);
                    if (dest[0] != MP_OBJ_NULL) {
                        if (match_str == NULL) {
                            match_str = d_str;
                            match_len = d_len;
                        } else {
                            // search for longest common prefix of match_str and d_str
                            // (assumes these strings are null-terminated)
                            for (size_t j = s_len; j <= match_len && j <= d_len; ++j) {
                                if (match_str[j] != d_str[j]) {
                                    match_len = j;
                                    break;
                                }
                            }
                        }
                        if (q_first == 0) {
                            q_first = q;
                        }
                        q_last = q;
                    }
                }
            }

            // nothing found
            if (q_first == 0) {
                // If there're no better alternatives, and if it's first word
                // in the line, try to complete "import".
                if (s_start == org_str) {
                    static const char import_str[] = "import ";
                    if (memcmp(s_start, import_str, s_len) == 0) {
                        *compl_str = import_str + s_len;
                        return sizeof(import_str) - 1 - s_len;
                    }
                }

                return 0;
            }

            // 1 match found, or multiple matches with a common prefix
            if (q_first == q_last || match_len > s_len) {
                *compl_str = match_str + s_len;
                return match_len - s_len;
            }

            // multiple matches found, print them out

            #define WORD_SLOT_LEN (16)
            #define MAX_LINE_LEN  (4 * WORD_SLOT_LEN)

            int line_len = MAX_LINE_LEN; // force a newline for first word
            for (qstr q = q_first; q <= q_last; ++q) {
                size_t d_len;
                const char *d_str = (const char*)qstr_data(q, &d_len);
                if (s_len <= d_len && strncmp(s_start, d_str, s_len) == 0) {
                    mp_load_method_protected(obj, q, dest, true);
                    if (dest[0] != MP_OBJ_NULL) {
                        int gap = (line_len + WORD_SLOT_LEN - 1) / WORD_SLOT_LEN * WORD_SLOT_LEN - line_len;
                        if (gap < 2) {
                            gap += WORD_SLOT_LEN;
                        }
                        if (line_len + gap + d_len <= MAX_LINE_LEN) {
                            // TODO optimise printing of gap?
                            for (int j = 0; j < gap; ++j) {
                                mp_print_str(print, " ");
                            }
                            mp_print_str(print, d_str);
                            line_len += gap + d_len;
                        } else {
                            mp_printf(print, "\n%s", d_str);
                            line_len = d_len;
                        }
                    }
                }
            }
            mp_print_str(print, "\n");

            return (size_t)(-1); // indicate many matches
        }
    }
}

#endif // MICROPY_HELPER_REPL