#include <assert.h>

#include "apfl.h"
#include "internal.h"
#include "resizable.h"
#include "hashmap.h"

struct apfl_list_data {
    unsigned refcount;
    struct apfl_value *items;
    size_t len;
};

struct apfl_dict_data {
    unsigned refcount;
    apfl_hashmap map;
};

static apfl_hash value_hash(const struct apfl_value);

apfl_list
apfl_list_incref(apfl_list list)
{
    if (list == NULL) {
        return NULL;
    }
    list->refcount++;
    return list;
}

void
apfl_list_unref(apfl_list list)
{
    if (list == NULL || !apfl_refcount_dec(&list->refcount)) {
        return;
    }

    for (size_t i = 0; i < list->len; i++) {
        apfl_value_deinit(&list->items[i]);
    }

    free(list->items);
    free(list);
}

static bool
dict_keys_eq(void *opaque, const void *a, const void *b)
{
    (void)opaque;
    return apfl_value_eq(*((struct apfl_value *) a), *((struct apfl_value *) b));
}

static apfl_hash
dict_calc_hash(void *opaque, const void *key)
{
    (void)opaque;
    return value_hash(*(const struct apfl_value *)key);
}

static void
dict_destroy_key_or_value(void *opaque, void *kv)
{
    (void)opaque;
    apfl_value_deinit(kv);
}

static void
dict_copy_key_or_value(void *opaque, void *_dest, void *_src)
{
    (void)opaque;

    struct apfl_value *dest = _dest;
    struct apfl_value *src = _src;

    *dest = apfl_value_incref(*src);
}

static const struct apfl_hashmap_callbacks dict_hashmap_callbacks = {
    .opaque        = NULL,
    .keys_eq       = dict_keys_eq,
    .calc_hash     = dict_calc_hash,
    .destroy_key   = dict_destroy_key_or_value,
    .destroy_value = dict_destroy_key_or_value,
    .copy_key      = dict_copy_key_or_value,
    .copy_value    = dict_copy_key_or_value,
};

static apfl_hashmap
new_hashmap_for_dict(void)
{
    return apfl_hashmap_new(
        dict_hashmap_callbacks,
        sizeof(struct apfl_value),
        sizeof(struct apfl_value)
    );
}

apfl_dict
apfl_dict_incref(apfl_dict dict)
{
    if (dict == NULL) {
        return NULL;
    }
    dict->refcount++;
    return dict;
}

void
apfl_dict_unref(apfl_dict dict)
{
    if (dict == NULL || !apfl_refcount_dec(&dict->refcount)) {
        return;
    }

    apfl_hashmap_destroy(dict->map);
    free(dict);
}

static void
print(unsigned indent, FILE *out, struct apfl_value value, bool skip_first_indent)
{
    struct apfl_string_view sv;
    unsigned first_indent = skip_first_indent ? 0 : indent;

    switch (value.type) {
    case APFL_VALUE_NIL:
        apfl_print_indented(first_indent, out, "nil");
        return;
    case APFL_VALUE_BOOLEAN:
        apfl_print_indented(first_indent, out, value.boolean ? "true" : "false");
        return;
    case APFL_VALUE_NUMBER:
        apfl_print_indented(first_indent, out, "%f", value.number);
        return;
    case APFL_VALUE_STRING:
        sv = apfl_string_view_from(value.string);
        apfl_print_indented(first_indent, out, "\"" APFL_STR_FMT "\"", APFL_STR_FMT_ARGS(sv));
        return;
    case APFL_VALUE_LIST:
        if (value.list->len == 0) {
            apfl_print_indented(first_indent, out, "[]");
            return;
        }
        apfl_print_indented(first_indent, out, "[\n");
        for (size_t i = 0; i < value.list->len; i++) {
            print(indent+1, out, value.list->items[i], false);
            apfl_print_indented(indent, out, "\n");
        }
        apfl_print_indented(indent, out, "]");
        return;
    case APFL_VALUE_DICT:
        if (apfl_hashmap_count(value.dict->map) == 0) {
            apfl_print_indented(first_indent, out, "[->]");
            return;
        }

        apfl_hashmap_cursor cur = apfl_hashmap_get_cursor(value.dict->map);
        if (cur == NULL) {
            return; // TODO: Handle failure in a better way
        }

        apfl_print_indented(first_indent, out, "[\n");
        for (; !apfl_hashmap_cursor_is_end(cur); apfl_hashmap_cursor_next(cur)) {
            struct apfl_value k, v;
            apfl_hashmap_cursor_get_key(cur, &k);
            apfl_hashmap_cursor_get_value(cur, &v);

            print(indent+1, out, k, false);
            apfl_value_deinit(&k);
            fprintf(out, " -> ");
            print(indent+1, out, v, true);
            apfl_value_deinit(&v);
            fprintf(out, "\n");
        }
        apfl_hashmap_cursor_destroy(cur);
        apfl_print_indented(indent, out, "]");
        return;
    }

    fprintf(out, "Unknown value? (%d)\n", (int)value.type);
}

struct apfl_value
apfl_value_move(struct apfl_value *src)
{
    struct apfl_value out = *src;
    src->type = APFL_VALUE_NIL;
    return out;
}

struct apfl_value
apfl_value_incref(struct apfl_value value)
{
    switch (value.type) {
    case APFL_VALUE_NIL:
    case APFL_VALUE_BOOLEAN:
    case APFL_VALUE_NUMBER:
        // Nothing to do
        return value;
    case APFL_VALUE_STRING:
        value.string = apfl_refcounted_string_incref(value.string);
        return value;
    case APFL_VALUE_LIST:
        value.list = apfl_list_incref(value.list);
        return value;
    case APFL_VALUE_DICT:
        value.dict = apfl_dict_incref(value.dict);
        return value;
    }

    assert(false);

    return value;
}

void
apfl_value_print(struct apfl_value value, FILE *out)
{
    print(0, out, value, false);
    fprintf(out, "\n");
}

static bool
list_eq(apfl_list a, apfl_list b)
{
    if (a == b) {
        return true;
    }

    if (a->len != b->len) {
        return true;
    }

    for (size_t i = 0; i < a->len; i++) {
        if (!apfl_value_eq(a->items[i], b->items[i])) {
            return false;
        }
    }
    return true;
}

static bool
dict_eq_inner(apfl_hashmap_cursor cur, const apfl_dict b)
{
    size_t total = 0;
    for (; !apfl_hashmap_cursor_is_end(cur); apfl_hashmap_cursor_next(cur)) {
        struct apfl_value key;
        struct apfl_value val;

        apfl_hashmap_cursor_get_key(cur, &key);
        apfl_hashmap_cursor_get_value(cur, &val);

        struct apfl_value other_val;
        if (!apfl_hashmap_get(b->map, &key, &other_val)) {
            apfl_value_deinit(&key);
            apfl_value_deinit(&val);
            return false;
        }

        bool eq = apfl_value_eq(val, other_val);
        apfl_value_deinit(&key);
        apfl_value_deinit(&val);
        apfl_value_deinit(&other_val);

        if (!eq) {
            return false;
        }
        total++;
    }

    return total == apfl_hashmap_count(b->map);
}

static bool
dict_eq(const apfl_dict a, const apfl_dict b)
{
    if (a == b) {
        return true;
    }

    apfl_hashmap_cursor cur = apfl_hashmap_get_cursor(a->map);
    if (cur == NULL) {
        assert(false); // TODO: It's rather ugly that this can fail and that we return false then!
        return false;
    }

    bool eq = dict_eq_inner(cur, b);
    apfl_hashmap_cursor_destroy(cur);
    return eq;
}

bool
apfl_value_eq(const struct apfl_value a, const struct apfl_value b)
{
    if (a.type != b.type) {
        return false;
    }

    switch (a.type) {
    case APFL_VALUE_NIL:
        return true;
    case APFL_VALUE_BOOLEAN:
        return a.boolean == b.boolean;
    case APFL_VALUE_NUMBER:
        return a.number == b.number;
    case APFL_VALUE_STRING:
        return apfl_string_eq(a.string, b.string);
    case APFL_VALUE_LIST:
        return list_eq(a.list, b.list);
    case APFL_VALUE_DICT:
        return dict_eq(a.dict, b.dict);
    }

    assert(false);
    return false;
}

struct apfl_editable_list_data {
    struct apfl_value *items;
    size_t len;
    size_t cap;
};

apfl_editable_list
apfl_editable_list_new(void)
{
    apfl_editable_list elist = ALLOC(struct apfl_editable_list_data);
    if (elist == NULL) {
        return NULL;
    }

    elist->items = NULL;
    elist->len = 0;
    elist->cap = 0;

    return elist;
}

apfl_editable_list
apfl_editable_list_new_from_list(apfl_list list)
{
    if (list == NULL) {
        return NULL;
    }

    apfl_editable_list elist = ALLOC(struct apfl_editable_list_data);
    if (elist == NULL) {
        apfl_list_unref(list);
        return NULL;
    }

    if (list->refcount == 1) {
        // We're the only one with a reference to the list, so we can directly use the items of the list!
        elist->items = list->items;
        elist->len = list->len;
        elist->cap = list->len;
    } else {
        // We fisrt need to create a shallow copy of the elements
        if ((elist->items = ALLOC_LIST(struct apfl_value, list->len)) == NULL) {
            apfl_list_unref(list);
            free(elist);
            return NULL;
        }

        for (size_t i = 0; i < list->len; i++) {
            elist->items[i] = apfl_value_incref(list->items[i]);
        }

        elist->len = list->len;
        elist->cap = list->len;
    }

    apfl_list_unref(list);

    return elist;
}

static bool
editable_list_append_values(apfl_editable_list elist, struct apfl_value *values, size_t len)
{
    if (!apfl_resizable_ensure_cap_for_more_elements(
        sizeof(struct apfl_value),
        (void **)&elist->items,
        elist->len,
        &elist->cap,
        len
    )) {
        return false;
    }

    for (size_t i = 0; i < len; i++) {
        elist->items[elist->len] = apfl_value_incref(values[i]);
        elist->len++;
    }

    return true;
}

bool
apfl_editable_list_append(apfl_editable_list elist, struct apfl_value value)
{
    bool ok = editable_list_append_values(elist, &value, 1);
    apfl_value_deinit(&value);
    return ok;
}

bool
apfl_editable_list_append_list(apfl_editable_list elist, apfl_list list)
{
    bool ok = editable_list_append_values(elist, list->items, list->len);
    apfl_list_unref(list);
    return ok;
}

void
apfl_editable_list_destroy(apfl_editable_list elist)
{
    if (elist == NULL) {
        return;
    }

    if (elist->items != NULL) {
        for (size_t i = 0; i < elist->len; i++) {
            apfl_value_deinit(&elist->items[i]);
        }
        free(elist->items);
    }

    free(elist);
}

apfl_list
apfl_editable_list_finalize(apfl_editable_list elist)
{
    apfl_list list = ALLOC(struct apfl_list_data);
    if (list == NULL) {
        apfl_editable_list_destroy(elist);
        return NULL;
    }

    list->refcount = 1;
    list->items = elist->items; // TODO: Maybe shrink memory with realloc?
    list->len = elist->len;

    free(elist);

    return list;
}


struct apfl_editable_dict_data {
    apfl_hashmap map;
};

apfl_editable_dict
apfl_editable_dict_new(void)
{
    apfl_editable_dict ed = ALLOC(struct apfl_editable_dict_data);
    if (ed == NULL) {
        return NULL;
    }

    if ((ed->map = new_hashmap_for_dict()) == NULL) {
        free(ed);
        return NULL;
    }

    return ed;
}

apfl_editable_dict
apfl_editable_dict_new_from_dict(apfl_dict dict)
{
    if (dict->refcount == 0) {
        return NULL;
    }

    apfl_editable_dict ed = ALLOC(struct apfl_editable_dict_data);
    if (ed == NULL) {
        apfl_dict_unref(dict);
        return NULL;
    }

    if (dict->refcount == 1) {
        // We're the only one having a reference to the dict. We can directly use it's hashmap!
        MOVEPTR(ed->map, dict->map);
    } else {
        // There are other places referencing the dict, we need to create a shallow copy first.
        if ((ed->map = apfl_hashmap_copy(dict->map)) == NULL) {
            free(ed);
            apfl_dict_unref(dict);
            return NULL;
        }
    }

    apfl_dict_unref(dict);

    return ed;
}

bool
apfl_editable_dict_set(apfl_editable_dict ed, struct apfl_value key, struct apfl_value value)
{
    if (ed == NULL || ed->map == NULL) {
        return false;
    }

    bool ok = apfl_hashmap_set(ed->map, &key, &value);
    apfl_value_deinit(&key);
    apfl_value_deinit(&value);
    return ok;
}

void
apfl_editable_dict_delete(apfl_editable_dict ed, struct apfl_value key)
{
    if (ed == NULL || ed->map == NULL) {
        return;
    }

    apfl_hashmap_delete(ed->map, &key);
    apfl_value_deinit(&key);
}

apfl_dict
apfl_editable_dict_finalize(apfl_editable_dict ed)
{
    if (ed == NULL || ed->map == NULL) {
        return NULL;
    }

    apfl_dict dict = ALLOC(struct apfl_dict_data);
    if (dict == NULL) {
        apfl_editable_dict_destroy(ed);
        return NULL;
    }

    dict->refcount = 1;
    MOVEPTR(dict->map, ed->map);

    free(ed);

    return dict;
}

void
apfl_editable_dict_destroy(apfl_editable_dict ed)
{
    if (ed == NULL) {
        return;
    }

    apfl_hashmap_destroy(ed->map);
    free(ed);
}

void
apfl_value_deinit(struct apfl_value *value)
{
    switch (value->type) {
    case APFL_VALUE_NIL:
    case APFL_VALUE_BOOLEAN:
    case APFL_VALUE_NUMBER:
        goto ok;
    case APFL_VALUE_STRING:
        apfl_refcounted_string_unref(value->string);
        value->string = NULL;
        goto ok;
    case APFL_VALUE_LIST:
        apfl_list_unref(value->list);
        value->list = NULL;
        goto ok;
    case APFL_VALUE_DICT:
        apfl_dict_unref(value->dict);
        value->dict = NULL;
        goto ok;
    }

    assert(false);

ok:
    value->type = APFL_VALUE_NIL;
}

bool
apfl_list_get_item(apfl_list list, size_t index, struct apfl_value *out)
{
    if (index >= list->len) {
        apfl_list_unref(list);
        return false;
    }

    *out = apfl_value_incref(list->items[index]);
    apfl_list_unref(list);
    return true;
}

bool
apfl_dict_get_item(apfl_dict dict, struct apfl_value key, struct apfl_value *out)
{
    bool ok = apfl_hashmap_get(dict->map, &key, out);
    apfl_dict_unref(dict);
    apfl_value_deinit(&key);
    return ok;
}

static enum apfl_value_get_item_result
get_item(/*borrowed*/ struct apfl_value container, /*borrowed*/ struct apfl_value key, struct apfl_value *out)
{
    if (container.type == APFL_VALUE_LIST) {
        if (key.type != APFL_VALUE_NUMBER) {
            return APFL_VALUE_GET_ITEM_WRONG_KEY_TYPE;
        }

        return apfl_list_get_item(
            apfl_list_incref(container.list),
            (size_t)key.number,
            out
        )
            ? APFL_VALUE_GET_ITEM_OK
            : APFL_VALUE_GET_ITEM_KEY_DOESNT_EXIST;
    } else if (container.type == APFL_VALUE_DICT) {
        return apfl_dict_get_item(
            apfl_dict_incref(container.dict),
            apfl_value_incref(key),
            out
        )
            ? APFL_VALUE_GET_ITEM_OK
            : APFL_VALUE_GET_ITEM_KEY_DOESNT_EXIST;
    } else {
        return APFL_VALUE_GET_ITEM_NOT_A_CONTAINER;
    }
}

enum apfl_value_get_item_result
apfl_value_get_item(struct apfl_value container, struct apfl_value key, struct apfl_value *out)
{
    enum apfl_value_get_item_result result = get_item(container, key, out);
    apfl_value_deinit(&container);
    apfl_value_deinit(&key);
    return result;
}

static apfl_hash
value_hash(const struct apfl_value value)
{
    apfl_hash hash = apfl_hash_fnv1a(&value.type, sizeof(enum apfl_value_type));

    struct apfl_string_view sv;

    switch (value.type) {
    case APFL_VALUE_NIL:
        goto ok;
    case APFL_VALUE_BOOLEAN:
        hash = apfl_hash_fnv1a_add(&value.boolean, sizeof(bool), hash);
        goto ok;
    case APFL_VALUE_NUMBER:
        hash = apfl_hash_fnv1a_add(&value.number, sizeof(apfl_number), hash);
        goto ok;
    case APFL_VALUE_STRING:
        sv = apfl_string_view_from(value.string);
        hash = apfl_hash_fnv1a_add(sv.bytes, sv.len, hash);
        goto ok;
    case APFL_VALUE_LIST:
        for (size_t i = 0; i < value.list->len; i++) {
            apfl_hash item_hash = value_hash(value.list->items[i]);
            hash = apfl_hash_fnv1a_add(&item_hash, sizeof(apfl_hash), hash);
        }
        goto ok;
    case APFL_VALUE_DICT:
        // TODO: This results in all dictionaries having the same hash. Since
        //       it's rather unusual to have dictionaries as keys, this is fine
        //       for now, but should be improved nonetheless!
        goto ok;
    }

    assert(false);

ok:
    return hash;
}