/*
* Copyright (c) 2018 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 "gc.h"
#include <string.h>

/* Initializes an array */
JanetArray *janet_array_init(JanetArray *array, int32_t capacity) {
    Janet *data = NULL;
    if (capacity > 0) {
        data = (Janet *) malloc(sizeof(Janet) * capacity);
        if (NULL == data) {
            JANET_OUT_OF_MEMORY;
        }
    }
    array->count = 0;
    array->capacity = capacity;
    array->data = data;
    return array;
}

void janet_array_deinit(JanetArray *array) {
    free(array->data);
}

/* Creates a new array */
JanetArray *janet_array(int32_t capacity) {
    JanetArray *array = janet_gcalloc(JANET_MEMORY_ARRAY, sizeof(JanetArray));
    return janet_array_init(array, capacity);
}

/* Creates a new array from n elements. */
JanetArray *janet_array_n(const Janet *elements, int32_t n) {
    JanetArray *array = janet_gcalloc(JANET_MEMORY_ARRAY, sizeof(JanetArray));
    array->capacity = n;
    array->count = n;
    array->data = malloc(sizeof(Janet) * n);
    if (!array->data) {
        JANET_OUT_OF_MEMORY;
    }
    memcpy(array->data, elements, sizeof(Janet) * n);
    return array;
}

/* Ensure the array has enough capacity for elements */
void janet_array_ensure(JanetArray *array, int32_t capacity, int32_t growth) {
    Janet *newData;
    Janet *old = array->data;
    if (capacity <= array->capacity) return;
    capacity *= growth;
    newData = realloc(old, capacity * sizeof(Janet));
    if (NULL == newData) {
        JANET_OUT_OF_MEMORY;
    }
    array->data = newData;
    array->capacity = capacity;
}

/* Set the count of an array. Extend with nil if needed. */
void janet_array_setcount(JanetArray *array, int32_t count) {
    if (count < 0)
        return;
    if (count > array->count) {
        int32_t i;
        janet_array_ensure(array, count, 1);
        for (i = array->count; i < count; i++) {
            array->data[i] = janet_wrap_nil();
        }
    }
    array->count = count;
}

/* Push a value to the top of the array */
void janet_array_push(JanetArray *array, Janet x) {
    int32_t newcount = array->count + 1;
    janet_array_ensure(array, newcount, 2);
    array->data[array->count] = x;
    array->count = newcount;
}

/* Pop a value from the top of the array */
Janet janet_array_pop(JanetArray *array) {
    if (array->count) {
        return array->data[--array->count];
    } else {
        return janet_wrap_nil();
    }
}

/* Look at the last value in the array */
Janet janet_array_peek(JanetArray *array) {
    if (array->count) {
        return array->data[array->count - 1];
    } else {
        return janet_wrap_nil();
    }
}

/* C Functions */

static int cfun_new(JanetArgs args) {
    int32_t cap;
    JanetArray *array;
    JANET_FIXARITY(args, 1);
    JANET_ARG_INTEGER(cap, args, 0);
    array = janet_array(cap);
    JANET_RETURN_ARRAY(args, array);
}

static int cfun_pop(JanetArgs args) {
    JanetArray *array;
    JANET_FIXARITY(args, 1);
    JANET_ARG_ARRAY(array, args, 0);
    JANET_RETURN(args, janet_array_pop(array));
}

static int cfun_peek(JanetArgs args) {
    JanetArray *array;
    JANET_FIXARITY(args, 1);
    JANET_ARG_ARRAY(array, args, 0);
    JANET_RETURN(args, janet_array_peek(array));
}

static int cfun_push(JanetArgs args) {
    JanetArray *array;
    int32_t newcount;
    JANET_MINARITY(args, 1);
    JANET_ARG_ARRAY(array, args, 0);
    newcount = array->count - 1 + args.n;
    janet_array_ensure(array, newcount, 2);
    if (args.n > 1) memcpy(array->data + array->count, args.v + 1, (args.n - 1) * sizeof(Janet));
    array->count = newcount;
    JANET_RETURN(args, args.v[0]);
}

static int cfun_ensure(JanetArgs args) {
    JanetArray *array;
    int32_t newcount;
    int32_t growth;
    JANET_FIXARITY(args, 3);
    JANET_ARG_ARRAY(array, args, 0);
    JANET_ARG_INTEGER(newcount, args, 1);
    JANET_ARG_INTEGER(growth, args, 2);
    if (newcount < 0) JANET_THROW(args, "expected positive integer");
    janet_array_ensure(array, newcount, growth);
    JANET_RETURN(args, args.v[0]);
}

static int cfun_slice(JanetArgs args) {
    const Janet *vals;
    int32_t len;
    JanetArray *ret;
    int32_t start, end;
    JANET_MINARITY(args, 1);
    JANET_MAXARITY(args, 3);
    if (!janet_indexed_view(args.v[0], &vals, &len))
        JANET_THROW(args, "expected array|tuple");
    /* Get start */
    if (args.n < 2) {
        start = 0;
    } else if (janet_checktype(args.v[1], JANET_INTEGER)) {
        start = janet_unwrap_integer(args.v[1]);
    } else {
        JANET_THROW(args, "expected integer");
    }
    /* Get end */
    if (args.n < 3) {
        end = -1;
    } else if (janet_checktype(args.v[2], JANET_INTEGER)) {
        end = janet_unwrap_integer(args.v[2]);
    } else {
        JANET_THROW(args, "expected integer");
    }
    if (start < 0) start = len + start;
    if (end < 0) end = len + end + 1;
    if (end >= start) {
        ret = janet_array(end - start);
        memcpy(ret->data, vals + start, sizeof(Janet) * (end - start));
        ret->count = end - start;
    } else {
        ret = janet_array(0);
    }
    JANET_RETURN_ARRAY(args, ret);
}

static int cfun_concat(JanetArgs args) {
    int32_t i;
    JanetArray *array;
    JANET_MINARITY(args, 1);
    JANET_ARG_ARRAY(array, args, 0);
    for (i = 1; i < args.n; i++) {
        switch (janet_type(args.v[i])) {
            default:
                janet_array_push(array, args.v[i]);
                break;
            case JANET_ARRAY:
            case JANET_TUPLE:
                {
                    int32_t j, len;
                    const Janet *vals;
                    janet_indexed_view(args.v[i], &vals, &len);
                    for (j = 0; j < len; j++)
                        janet_array_push(array, vals[j]);
                }
                break;
        }
    }
    JANET_RETURN_ARRAY(args, array);
}

static const JanetReg cfuns[] = {
    {"array.new", cfun_new,
        "(array.new capacity)\n\n"
        "Creates a new empty array with a preallocated capacity. The same as\n"
        "(array) but can be more efficient if the maximum size of an array is known."
    },
    {"array.pop", cfun_pop,
        "(array.pop arr)\n\n"
        "Remove the last element of the array and return it. If the array is empty, will return nil. Modifies\n"
        "the input array."
    },
    {"array.peek", cfun_peek,
        "(array.peel arr)\n\n"
        "Returns the last element of the array. Does not modify the array."
    },
    {"array.push", cfun_push,
        "(array.push arr x)\n\n"
        "Insert an element in the end of an array. Modifies the input array and returns it."
    },
    {"array.ensure", cfun_ensure,
        "(array.ensure arr capacity)\n\n"
        "Ensures that the memory backing the array has enough memory for capacity\n"
        "items. Capacity must be an integer. If the backing capacity is already enough,\n"
        "then this function does nothing. Otherwise, the backing memory will be reallocated\n"
        "so that there is enough space."
    },
    {"array.slice", cfun_slice,
        "(array.slice arrtup)\n\n"
        "Returns a copy of an array or tuple.\n\n"
        "(array.slice arrtup start)\n\n"
        "Takes a slice of an array or tuple from the index start to the last element. Indexes\n"
        "are from 0, or can be negative to index from the end of the array, Where -1 is the last\n"
        "element of the array. Returns a new array.\n\n"
        "(array.slice arrtup start end)\n\n"
        "Takes a slice of array or tuple from start to end. The range is half open,\n"
        "[start, end). Indexes can also be negative, indicating indexing from the end of the\n"
        "end of the array. Returns a new array."
    },
    {"array.concat", cfun_concat,
        "(array.concat arr & parts)\n\n"
        "Concatenates a variadic number of arrays (and tuples) into the first argument\n"
        "which must an array. If any of the parts are arrays or tuples, their elements will\n"
        "be inserted into the array. Otherwise, each part in parts will be appended to arr in order.\n"
        "Return the modified array arr."
    },
    {NULL, NULL, NULL}
};

/* Load the array module */
int janet_lib_array(JanetArgs args) {
    JanetTable *env = janet_env(args);
    janet_cfuns(env, NULL, cfuns);
    return 0;
}