/*
* Copyright (c) 2019 Calvin Rose
*
* 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 <janet/janet.h>
#include "symcache.h"
#include "gc.h"
#include "util.h"

/* Create a new empty tuple of the given size. This will return memory
 * which should be filled with Janets. The memory will not be collected until
 * janet_tuple_end is called. */
Janet *janet_tuple_begin(int32_t length) {
    char *data = janet_gcalloc(JANET_MEMORY_TUPLE, 4 * sizeof(int32_t) + length * sizeof(Janet));
    Janet *tuple = (Janet *)(data + (4 * sizeof(int32_t)));
    janet_tuple_length(tuple) = length;
    janet_tuple_sm_start(tuple) = -1;
    janet_tuple_sm_end(tuple) = -1;
    return tuple;
}

/* Finish building a tuple */
const Janet *janet_tuple_end(Janet *tuple) {
    janet_tuple_hash(tuple) = janet_array_calchash(tuple, janet_tuple_length(tuple));
    return (const Janet *)tuple;
}

/* Build a tuple with n values */
const Janet *janet_tuple_n(const Janet *values, int32_t n) {
    Janet *t = janet_tuple_begin(n);
    memcpy(t, values, sizeof(Janet) * n);
    return janet_tuple_end(t);
}

/* Check if two tuples are equal */
int janet_tuple_equal(const Janet *lhs, const Janet *rhs) {
    int32_t index;
    int32_t llen = janet_tuple_length(lhs);
    int32_t rlen = janet_tuple_length(rhs);
    int32_t lhash = janet_tuple_hash(lhs);
    int32_t rhash = janet_tuple_hash(rhs);
    if (lhash == 0)
        lhash = janet_tuple_hash(lhs) = janet_array_calchash(lhs, llen);
    if (rhash == 0)
        rhash = janet_tuple_hash(rhs) = janet_array_calchash(rhs, rlen);
    if (lhash != rhash)
        return 0;
    if (llen != rlen)
        return 0;
    for (index = 0; index < llen; index++) {
        if (!janet_equals(lhs[index], rhs[index]))
            return 0;
    }
    return 1;
}

/* Compare tuples */
int janet_tuple_compare(const Janet *lhs, const Janet *rhs) {
    int32_t i;
    int32_t llen = janet_tuple_length(lhs);
    int32_t rlen = janet_tuple_length(rhs);
    int32_t count = llen < rlen ? llen : rlen;
    for (i = 0; i < count; ++i) {
        int comp = janet_compare(lhs[i], rhs[i]);
        if (comp != 0) return comp;
    }
    if (llen < rlen)
        return -1;
    else if (llen > rlen)
        return 1;
    return 0;
}

/* C Functions */

static Janet cfun_slice(int32_t argc, Janet *argv) {
    JanetRange range = janet_getslice(argc, argv);
    JanetView view = janet_getindexed(argv, 0);
    return janet_wrap_tuple(janet_tuple_n(view.items + range.start, range.end - range.start));
}

static Janet cfun_prepend(int32_t argc, Janet *argv) {
    janet_arity(argc, 1, -1);
    JanetView view = janet_getindexed(argv, 0);
    Janet *n = janet_tuple_begin(view.len - 1 + argc);
    memcpy(n - 1 + argc, view.items, sizeof(Janet) * view.len);
    for (int32_t i = 1; i < argc; i++) {
        n[argc - i - 1] = argv[i];
    }
    return janet_wrap_tuple(janet_tuple_end(n));
}

static Janet cfun_append(int32_t argc, Janet *argv) {
    janet_arity(argc, 1, -1);
    JanetView view = janet_getindexed(argv, 0);
    Janet *n = janet_tuple_begin(view.len - 1 + argc);
    memcpy(n, view.items, sizeof(Janet) * view.len);
    memcpy(n + view.len, argv + 1, sizeof(Janet) * (argc - 1));
    return janet_wrap_tuple(janet_tuple_end(n));
}

static const JanetReg cfuns[] = {
    {
        "tuple/slice", cfun_slice,
        JDOC("(tuple/slice arrtup [,start=0 [,end=(length arrtup)]])\n\n"
                "Take a sub sequence of an array or tuple from index start "
                "inclusive to index end exclusive. If start or end are not provided, "
                "they default to 0 and the length of arrtup respectively."
                "Returns the new tuple.")
    },
    {
        "tuple/append", cfun_append,
        JDOC("(tuple/append tup & items)\n\n"
                "Returns a new tuple that is the result of appending "
                "each element in items to tup.")
    },
    {
        "tuple/prepend", cfun_prepend,
        JDOC("(tuple/prepend tup & items)\n\n"
                "Prepends each element in items to tuple and "
                "returns a new tuple. Items are prepended such that the "
                "last element in items is the first element in the new tuple.")
    },
    {NULL, NULL, NULL}
};

/* Load the tuple module */
void janet_lib_tuple(JanetTable *env) {
    janet_cfuns(env, NULL, cfuns);
}