/*
* 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.
*/

#ifndef JANET_AMALG
#include <janet.h>
#endif

/*
 * Define a number of functions that can be used internally on ANY Janet.
 */

/* Check if two values are equal. This is strict equality with no conversion. */
int janet_equals(Janet x, Janet y) {
    int result = 0;
    if (janet_type(x) != janet_type(y)) {
        result = 0;
    } else {
        switch (janet_type(x)) {
            case JANET_NIL:
                result = 1;
                break;
            case JANET_BOOLEAN:
                result = (janet_unwrap_boolean(x) == janet_unwrap_boolean(y));
                break;
            case JANET_NUMBER:
                result = (janet_unwrap_number(x) == janet_unwrap_number(y));
                break;
            case JANET_STRING:
                result = janet_string_equal(janet_unwrap_string(x), janet_unwrap_string(y));
                break;
            case JANET_TUPLE:
                result = janet_tuple_equal(janet_unwrap_tuple(x), janet_unwrap_tuple(y));
                break;
            case JANET_STRUCT:
                result = janet_struct_equal(janet_unwrap_struct(x), janet_unwrap_struct(y));
                break;
            default:
                /* compare pointers */
                result = (janet_unwrap_pointer(x) == janet_unwrap_pointer(y));
                break;
        }
    }
    return result;
}

/* Computes a hash value for a function */
int32_t janet_hash(Janet x) {
    int32_t hash = 0;
    switch (janet_type(x)) {
        case JANET_NIL:
            hash = 0;
            break;
        case JANET_BOOLEAN:
            hash = janet_unwrap_boolean(x);
            break;
        case JANET_STRING:
        case JANET_SYMBOL:
        case JANET_KEYWORD:
            hash = janet_string_hash(janet_unwrap_string(x));
            break;
        case JANET_TUPLE:
            hash = janet_tuple_hash(janet_unwrap_tuple(x));
            break;
        case JANET_STRUCT:
            hash = janet_struct_hash(janet_unwrap_struct(x));
            break;
        default:
            /* TODO - test performance with different hash functions */
            if (sizeof(double) == sizeof(void *)) {
                /* Assuming 8 byte pointer */
                uint64_t i = janet_u64(x);
                hash = (int32_t)(i & 0xFFFFFFFF);
                /* Get a bit more entropy by shifting the low bits out */
                hash >>= 3;
                hash ^= (int32_t)(i >> 32);
            } else {
                /* Assuming 4 byte pointer (or smaller) */
                hash = (int32_t)((char *)janet_unwrap_pointer(x) - (char *)0);
                hash >>= 2;
            }
            break;
    }
    return hash;
}

/* Compares x to y. If they are equal returns 0. If x is less, returns -1.
 * If y is less, returns 1. All types are comparable
 * and should have strict ordering. */
int janet_compare(Janet x, Janet y) {
    if (janet_type(x) == janet_type(y)) {
        switch (janet_type(x)) {
            case JANET_NIL:
                return 0;
            case JANET_BOOLEAN:
                return janet_unwrap_boolean(x) - janet_unwrap_boolean(y);
            case JANET_NUMBER:
                /* Check for NaNs to ensure total order */
                if (janet_unwrap_number(x) != janet_unwrap_number(x))
                    return janet_unwrap_number(y) != janet_unwrap_number(y)
                           ? 0
                           : -1;
                if (janet_unwrap_number(y) != janet_unwrap_number(y))
                    return 1;

                if (janet_unwrap_number(x) == janet_unwrap_number(y)) {
                    return 0;
                } else {
                    return janet_unwrap_number(x) > janet_unwrap_number(y) ? 1 : -1;
                }
            case JANET_STRING:
            case JANET_SYMBOL:
            case JANET_KEYWORD:
                return janet_string_compare(janet_unwrap_string(x), janet_unwrap_string(y));
            case JANET_TUPLE:
                return janet_tuple_compare(janet_unwrap_tuple(x), janet_unwrap_tuple(y));
            case JANET_STRUCT:
                return janet_struct_compare(janet_unwrap_struct(x), janet_unwrap_struct(y));
            default:
                if (janet_unwrap_string(x) == janet_unwrap_string(y)) {
                    return 0;
                } else {
                    return janet_unwrap_string(x) > janet_unwrap_string(y) ? 1 : -1;
                }
        }
    }
    return (janet_type(x) < janet_type(y)) ? -1 : 1;
}

static int32_t getter_checkint(Janet key, int32_t max) {
    if (!janet_checkint(key)) goto bad;
    int32_t ret = janet_unwrap_integer(key);
    if (ret < 0) goto bad;
    if (ret >= max) goto bad;
    return ret;
bad:
    janet_panicf("expected integer key in range [0, %d), got %v", max, key);
}

/* Gets a value and returns. Can panic. */
Janet janet_get(Janet ds, Janet key) {
    Janet value;
    switch (janet_type(ds)) {
        default:
            janet_panicf("expected %T, got %v", JANET_TFLAG_LENGTHABLE, ds);
            break;
        case JANET_STRUCT:
            value = janet_struct_get(janet_unwrap_struct(ds), key);
            break;
        case JANET_TABLE:
            value = janet_table_get(janet_unwrap_table(ds), key);
            break;
        case JANET_ARRAY: {
            JanetArray *array = janet_unwrap_array(ds);
            int32_t index = getter_checkint(key, array->count);
            value = array->data[index];
            break;
        }
        case JANET_TUPLE: {
            const Janet *tuple = janet_unwrap_tuple(ds);
            int32_t len = janet_tuple_length(tuple);
            value = tuple[getter_checkint(key, len)];
            break;
        }
        case JANET_BUFFER: {
            JanetBuffer *buffer = janet_unwrap_buffer(ds);
            int32_t index = getter_checkint(key, buffer->count);
            value = janet_wrap_integer(buffer->data[index]);
            break;
        }
        case JANET_STRING:
        case JANET_SYMBOL:
        case JANET_KEYWORD: {
            const uint8_t *str = janet_unwrap_string(ds);
            int32_t index = getter_checkint(key, janet_string_length(str));
            value = janet_wrap_integer(str[index]);
            break;
        }
        case JANET_ABSTRACT: {
            JanetAbstractType *type = (JanetAbstractType *)janet_abstract_type(janet_unwrap_abstract(ds));
            if (type->get) {
                value = (type->get)(janet_unwrap_abstract(ds), key);
            } else {
                janet_panicf("no getter for %v ", ds);
            }
            break;
        }
    }
    return value;
}

Janet janet_getindex(Janet ds, int32_t index) {
    Janet value;
    if (index < 0) janet_panic("expected non-negative index");
    switch (janet_type(ds)) {
        default:
            janet_panicf("expected %T, got %v", JANET_TFLAG_LENGTHABLE, ds);
            break;
        case JANET_STRING:
        case JANET_SYMBOL:
        case JANET_KEYWORD:
            if (index >= janet_string_length(janet_unwrap_string(ds))) {
                value = janet_wrap_nil();
            } else {
                value = janet_wrap_integer(janet_unwrap_string(ds)[index]);
            }
            break;
        case JANET_ARRAY:
            if (index >= janet_unwrap_array(ds)->count) {
                value = janet_wrap_nil();
            } else {
                value = janet_unwrap_array(ds)->data[index];
            }
            break;
        case JANET_BUFFER:
            if (index >= janet_unwrap_buffer(ds)->count) {
                value = janet_wrap_nil();
            } else {
                value = janet_wrap_integer(janet_unwrap_buffer(ds)->data[index]);
            }
            break;
        case JANET_TUPLE:
            if (index >= janet_tuple_length(janet_unwrap_tuple(ds))) {
                value = janet_wrap_nil();
            } else {
                value = janet_unwrap_tuple(ds)[index];
            }
            break;
        case JANET_TABLE:
            value = janet_table_get(janet_unwrap_table(ds), janet_wrap_integer(index));
            break;
        case JANET_STRUCT:
            value = janet_struct_get(janet_unwrap_struct(ds), janet_wrap_integer(index));
            break;
        case JANET_ABSTRACT: {
            JanetAbstractType *type = (JanetAbstractType *)janet_abstract_type(janet_unwrap_abstract(ds));
            if (type->get) {
                value = (type->get)(janet_unwrap_abstract(ds), janet_wrap_integer(index));
            } else {
                janet_panicf("no getter for %v ", ds);
            }
            break;
        }
    }
    return value;
}

int32_t janet_length(Janet x) {
    switch (janet_type(x)) {
        default:
            janet_panicf("expected %T, got %v", JANET_TFLAG_LENGTHABLE, x);
        case JANET_STRING:
        case JANET_SYMBOL:
        case JANET_KEYWORD:
            return janet_string_length(janet_unwrap_string(x));
        case JANET_ARRAY:
            return janet_unwrap_array(x)->count;
        case JANET_BUFFER:
            return janet_unwrap_buffer(x)->count;
        case JANET_TUPLE:
            return janet_tuple_length(janet_unwrap_tuple(x));
        case JANET_STRUCT:
            return janet_struct_length(janet_unwrap_struct(x));
        case JANET_TABLE:
            return janet_unwrap_table(x)->count;
        case JANET_ABSTRACT: {
            Janet argv[1] = { x };
            Janet len = janet_mcall("length", 1, argv);
            if (!janet_checkint(len))
                janet_panicf("invalid integer length %v", len);
            return janet_unwrap_integer(len);
        }
    }
}

Janet janet_lengthv(Janet x) {
    switch (janet_type(x)) {
        default:
            janet_panicf("expected %T, got %v", JANET_TFLAG_LENGTHABLE, x);
        case JANET_STRING:
        case JANET_SYMBOL:
        case JANET_KEYWORD:
            return janet_wrap_integer(janet_string_length(janet_unwrap_string(x)));
        case JANET_ARRAY:
            return janet_wrap_integer(janet_unwrap_array(x)->count);
        case JANET_BUFFER:
            return janet_wrap_integer(janet_unwrap_buffer(x)->count);
        case JANET_TUPLE:
            return janet_wrap_integer(janet_tuple_length(janet_unwrap_tuple(x)));
        case JANET_STRUCT:
            return janet_wrap_integer(janet_struct_length(janet_unwrap_struct(x)));
        case JANET_TABLE:
            return janet_wrap_integer(janet_unwrap_table(x)->count);
        case JANET_ABSTRACT: {
            Janet argv[1] = { x };
            return janet_mcall("length", 1, argv);
        }
    }
}

void janet_putindex(Janet ds, int32_t index, Janet value) {
    switch (janet_type(ds)) {
        default:
            janet_panicf("expected %T, got %v",
                         JANET_TFLAG_ARRAY | JANET_TFLAG_BUFFER | JANET_TFLAG_TABLE, ds);
        case JANET_ARRAY: {
            JanetArray *array = janet_unwrap_array(ds);
            if (index >= array->count) {
                janet_array_ensure(array, index + 1, 2);
                array->count = index + 1;
            }
            array->data[index] = value;
            break;
        }
        case JANET_BUFFER: {
            JanetBuffer *buffer = janet_unwrap_buffer(ds);
            if (!janet_checkint(value))
                janet_panicf("can only put integers in buffers, got %v", value);
            if (index >= buffer->count) {
                janet_buffer_ensure(buffer, index + 1, 2);
                buffer->count = index + 1;
            }
            buffer->data[index] = (uint8_t)(janet_unwrap_integer(value) & 0xFF);
            break;
        }
        case JANET_TABLE: {
            JanetTable *table = janet_unwrap_table(ds);
            janet_table_put(table, janet_wrap_integer(index), value);
            break;
        }
        case JANET_ABSTRACT: {
            JanetAbstractType *type = (JanetAbstractType *)janet_abstract_type(janet_unwrap_abstract(ds));
            if (type->put) {
                (type->put)(janet_unwrap_abstract(ds), janet_wrap_integer(index), value);
            } else {
                janet_panicf("no setter for %v ", ds);
            }
            break;
        }
    }
}

void janet_put(Janet ds, Janet key, Janet value) {
    switch (janet_type(ds)) {
        default:
            janet_panicf("expected %T, got %v",
                         JANET_TFLAG_ARRAY | JANET_TFLAG_BUFFER | JANET_TFLAG_TABLE, ds);
        case JANET_ARRAY: {
            JanetArray *array = janet_unwrap_array(ds);
            int32_t index = getter_checkint(key, INT32_MAX - 1);
            if (index >= array->count) {
                janet_array_setcount(array, index + 1);
            }
            array->data[index] = value;
            break;
        }
        case JANET_BUFFER: {
            JanetBuffer *buffer = janet_unwrap_buffer(ds);
            int32_t index = getter_checkint(key, INT32_MAX - 1);
            if (!janet_checkint(value))
                janet_panicf("can only put integers in buffers, got %v", value);
            if (index >= buffer->count) {
                janet_buffer_setcount(buffer, index + 1);
            }
            buffer->data[index] = (uint8_t)(janet_unwrap_integer(value) & 0xFF);
            break;
        }
        case JANET_TABLE:
            janet_table_put(janet_unwrap_table(ds), key, value);
            break;
        case JANET_ABSTRACT: {
            JanetAbstractType *type = (JanetAbstractType *)janet_abstract_type(janet_unwrap_abstract(ds));
            if (type->put) {
                (type->put)(janet_unwrap_abstract(ds), key, value);
            } else {
                janet_panicf("no setter for %v ", ds);
            }
            break;
        }
    }
}