#include "CgeConfQuery.h"

#include <stdlib.h>
#include <string.h>

#define INIT_EXP 4
#define INIT_CAPACITY ((size_t)1 << INIT_EXP)
#define MAX_SECTION 4096

typedef struct {
    char *section;
    char *key;
    char *value;
} Entry;

struct CgeConfQuery {
    Entry *entryData;
    size_t size;
    size_t capacity;
    Entry **slotData;
    char currentSection[MAX_SECTION];
    int exp;
};

static char *stringDup(const char *str) {
    size_t length;
    char *dest;

    length = strlen(str);
    if ((dest = malloc(length + 1)))
        memcpy(dest, str, length + 1);
    return dest;
}

static size_t hashKey(const char *section, const char *key) {
    size_t h = 5381;
    const char *p;
    int c;

    for (p = section; (c = *p); ++p)
        h = ((h << 5) + h) + (unsigned char)c;
    h = ((h << 5) + h);
    for (p = key; (c = *p); ++p)
        h = ((h << 5) + h) + (unsigned char)c;

    return h;
}

static size_t lookup(size_t hash, int exp, size_t index) {
    size_t mask = (1 << exp) - 1;
    size_t step = (hash >> (sizeof(hash) * 8 - exp)) | 1;
    return (index + step) & mask;
}

static int reserveSpace(CgeConfQuery *query, size_t need) {
    CgeConfQuery tmp;
    size_t i, hash, index;

    if (need <= (query->capacity - (query->capacity >> 2)))
        return 1;

    tmp.exp = query->exp ? query->exp + 1 : INIT_EXP;
    tmp.capacity = query->capacity ? query->capacity * 2 : INIT_CAPACITY;
    tmp.size = 0;
    tmp.entryData = malloc(tmp.capacity * sizeof(*tmp.entryData));
    tmp.slotData = malloc(tmp.capacity * sizeof(*tmp.slotData));
    if (!tmp.entryData || !tmp.slotData) {
        free(tmp.entryData);
        free(tmp.slotData);
        return 0;
    }
    memset(tmp.slotData, 0, sizeof(*tmp.slotData) * tmp.capacity);

    for (i = 0; i < query->size; ++i) {
        Entry *entry = &query->entryData[i];

        hash = hashKey(entry->section, entry->key);
        index = lookup(hash, tmp.exp, 0);
        while (tmp.slotData[index] != NULL)
            index = lookup(hash, tmp.exp, index);

        tmp.entryData[tmp.size] = *entry;
        tmp.slotData[index] = tmp.entryData + tmp.size++;
    }

    free(query->entryData);
    free(query->slotData);
    query->entryData = tmp.entryData;
    query->slotData = tmp.slotData;
    query->capacity = tmp.capacity;
    query->exp = tmp.exp;
    return 1;
}

static int insert(CgeConfQuery *query, const char *section, const char *key,
                  const char *value) {
    size_t hash, index;
    char *newValue;
    Entry *entry;

    if (!reserveSpace(query, query->size + 1))
        return 0;

    hash = hashKey(section, key);
    index = lookup(hash, query->exp, 0);

    while ((entry = query->slotData[index])) {
        if (strcmp(entry->section, section) == 0 &&
            strcmp(entry->key, key) == 0) {
            newValue = stringDup(value);
            if (!newValue)
                return 0;
            free(entry->value);
            entry->value = newValue;
            return 1;
        }
        index = lookup(hash, query->exp, index);
    }

    entry = &query->entryData[query->size];
    entry->section = stringDup(section);
    entry->key = stringDup(key);
    entry->value = stringDup(value);
    if (!entry->section || !entry->key || !entry->value) {
        free(entry->section);
        free(entry->key);
        free(entry->value);
        return 0;
    }

    query->size++;
    query->slotData[index] = entry;
    return 1;
}

static void populateCb(int type, const char *key, const char *value,
                       void *user) {
    CgeConfQuery *query = (CgeConfQuery *)user;
    size_t len;

    if (type == CGE_CONF_SECTION) {
        len = strlen(value);
        if (len >= sizeof(query->currentSection))
            len = sizeof(query->currentSection) - 1;
        memcpy(query->currentSection, value, len);
        query->currentSection[len] = 0;
    } else if (type == CGE_CONF_KEYVALUE) {
        insert(query, query->currentSection, key, value);
    }
}

static CgeConfQuery *queryNew(void) {
    CgeConfQuery *query;

    query = (CgeConfQuery *)malloc(sizeof(CgeConfQuery));
    if (!query)
        return NULL;

    memset(query, 0, sizeof(*query));
    return query;
}

CgeConfQuery *CgeConfQueryFromCb(CgeConfIO *io) {
    CgeConfQuery *query;

    query = queryNew();
    if (!query)
        return NULL;

    if (!CgeConfFromCb(io, populateCb, query)) {
        CgeConfQueryFree(query);
        return NULL;
    }
    return query;
}

CgeConfQuery *CgeConfQueryFromFile(const char *file) {
    CgeConfQuery *query;

    query = queryNew();
    if (!query)
        return NULL;

    if (!CgeConfFromFile(file, populateCb, query)) {
        CgeConfQueryFree(query);
        return NULL;
    }
    return query;
}

CgeConfQuery *CgeConfQueryFromMemory(const char *buffer, size_t size) {
    CgeConfQuery *query;

    query = queryNew();
    if (!query)
        return NULL;

    if (!CgeConfFromMemory(buffer, size, populateCb, query)) {
        CgeConfQueryFree(query);
        return NULL;
    }
    return query;
}

CgeConfQuery *CgeConfQueryFromString(const char *str) {
    return CgeConfQueryFromMemory(str, strlen(str));
}

const char *CgeConfQueryGet(CgeConfQuery *query, const char *section,
                            const char *key, const char *defaultValue) {
    size_t hash, index, i;
    Entry *entry;

    if (!query || !key)
        return defaultValue;
    if (!section)
        section = "";

    hash = hashKey(section, key);
    index = lookup(hash, query->exp, 0);

    for (i = 0; i < query->capacity; ++i) {
        entry = query->slotData[index];
        if (!entry)
            break;
        if (strcmp(entry->section, section) == 0 &&
            strcmp(entry->key, key) == 0)
            return entry->value;
        index = lookup(hash, query->exp, index);
    }
    return defaultValue;
}

void CgeConfQueryFree(CgeConfQuery *query) {
    size_t i;

    if (!query)
        return;

    for (i = 0; i < query->size; ++i) {
        free(query->entryData[i].section);
        free(query->entryData[i].key);
        free(query->entryData[i].value);
    }
    free(query->entryData);
    free(query->slotData);
    free(query);
}

void CgeConfQueryIter(CgeConfQuery *query, CgeConfQueryIterCb iter,
                      void *user) {
    Entry *entry, *end;

    entry = query->entryData;
    end = query->entryData + query->size;
    for (; entry != end; ++entry)
        iter(entry->section, entry->key, entry->value, user);
}