#include "object.h"
#include <stdlib.h>
#include <string.h>
#include <stdio.h>

#define RESULT_LENGTH 20

#ifdef DEBUG
#define printd(...) printf(__VA_ARGS__)
#else
#define printd(...) stringObj(NULL, NULL)
#endif

#ifndef STANDALONE
#include <pebble.h>
#undef printf
#define printf(...) APP_LOG(APP_LOG_LEVEL_DEBUG, __VA_ARGS__)
#endif

#define FOR_POINTER_IN_LIST(_list) \
    for(Object *_element = _list->list; \
            _element != NULL;\
            _element = _element->forward)
#define POINTER _element

/**
 * Returns the length of a given list Object
 * @param listObj The list to get the length of
 * @return Length of the list if non-null and of the list type. Otherwise -1
 */
int listLength(const Object *listObj)
{
    if(!listObj || listObj->type != TYPE_LIST)
        return -1;

    int len = 0;
    FOR_POINTER_IN_LIST(listObj) {
        len++;
    }
    return len;
}

Object len(Object obj1, Object ignore)
    { return numberObject(listLength(&obj1)); }

/**
 * Returns a pointer to the Object at the given index in a given list
 * @param listObj The list to fetch an Object from
 * @param n The index to to fetch from the list
 * @return A pointer to the Object, if it is found, or NULL on an error
 */
Object *itemAt(const Object *listObj, int n)
{
    if(!listObj || listObj->type != TYPE_LIST)
        return NULL;

    Object *march = listObj->list;
    for(int i = 0; i < n; i++) {
        if(march == NULL)
            return NULL;
        march = march->forward;
    }
    return march;
}

/**
 * Returns a pointer to the last Object in the given list.
 * @param listObj The list to find the tail of
 * @return A pointer to the last Object if it is found, or NULL on an error
 */
Object *tail(const Object *listObj)
{
    if(!listObj || listObj->type != TYPE_LIST)
        return NULL;

    Object *march = listObj->list;
    while(march->forward != NULL) {
        march = march->forward;
    }
    return march;
}

/**
 * Checks if a given object is empty.
 *
 * BOOL, NUMBER, and ERROR types return true only when 0
 * LIST, LAMBDA, and FUNC types return true only when NULL
 * SYMBOL returns true only when it begins with a nullchar
 * @param obj A pointer to the object to check
 * @return True only if the non-null Object is empty/non-zero
 */
inline int isEmpty(const Object *obj)
{
    if(obj == NULL)
        return 0;

    switch(obj->type) {
        case TYPE_NUMBER:
        case TYPE_BOOL:
            return obj->number == 0;
        case TYPE_LIST:
            return obj->list == NULL;
        case TYPE_LAMBDA:
            return obj->lambda == NULL;
        case TYPE_SYMBOL:
            return obj->name[0] == '\0';
        case TYPE_FUNC:
            return obj->func == NULL;
        case TYPE_ERROR:
            return obj->err == 0;
        default:
            return 0;
    }
}

/**
 * Allocate a copy of a given object into the given pointer.
 * Does nothing if `spot` is NULL
 * @param spot A pointer to the Object pointer that needs allocating
 * @param src The Object to copy from
 */
void allocObject(Object **spot, const Object src)
{
    if(!spot)
        return;
    *spot = malloc(sizeof(struct Object));
    **spot = src;
    (*spot)->forward = NULL;
}

/**
 * Inserts a given Object into a list at the given index.
 * Immediately returns if `dest` is NULL or not a list type
 * Adds to the end of the list if the index is higher than the list length

 * @param dest The list to insert into
 * @param ind The index to insert at
 * @param src The Object to add to the list

 * @warning UNTESTED
 */
void insertIntoList(Object *dest, unsigned ind, const Object src)
{
    // Only work with non-null list types
    if(!dest || dest->type != TYPE_LIST)
        return;

    if(isEmpty(dest)) {
        allocObject(&dest->list, src);
        return;
    }

    // TODO Check for off-by-one errors 
    //      ensure pointers connect old and new
    Object *march = dest->list;
    for(unsigned i = 1; i < ind; i++) {
        if(march->forward == NULL) {
            allocObject(&march->forward, src);
            return;
        }
        march = march->forward;
    }

    // Save and re-apply current march->forward
    Object *oldForward = march->forward;
    allocObject(&march->forward, src);
    march->forward->forward = oldForward;
}

/**
 * Replace an object in a list at a given index with a given object
 * Attempts to clean the replaced Object before adding the new one
 * Immediately returns if `list` is NULL or not a list type
 * @param list The list Object to replace an element of
 * @param i The index of the element to replace
 * @param src The Object to copy into the list
 */
void replaceListing(Object *list, int i, const Object src)
{
    if(!list || list->type != TYPE_LIST)
        return;
    Object *replace = itemAt(list, i);
    cleanObject(replace);
    *replace = src;
    replace->forward = NULL;
}

/**
 * Adds an Object to the end of a list
 * Does nothing if `dest` is NULL or not a list type
 * @param dest The list to append to
 * @param src The Object to copy into the list
 */
void nf_addToList(Object *dest, const Object src)
{
    if(!dest || dest->type != TYPE_LIST)
        return;

    if(isEmpty(dest)) {
        allocObject(&dest->list, src);
        return;
    }

    allocObject(&tail(dest)->forward, src);
}

void printErr(const Object *obj)
{
    if(!obj || obj->type != TYPE_ERROR)
        return;

    printf("%s\n", errorText[(int)(obj->err)]);
}

void stringList(char *dest, const Object *obj)
{
    dest[0] = '(';
    dest[1] = '\0';

    const Object *tail = obj->list;
    while(tail != NULL) {
        strcat(dest, " ");
        char tok[90] = "";
        stringObj(tok, tail);
        strcat(dest, tok);
        tail = tail->forward;
    }
    strcat(dest, " )");
}

// Puts a string version of the given object into a given string
char* stringObj(char *dest, const Object *obj)
{
    if(!dest || !obj)
        return NULL;

    const Type t = obj->type;

    if(t == TYPE_NUMBER) {
        snprintf(dest, RESULT_LENGTH, "%d", obj->number);
    } else if(t == TYPE_SYMBOL) {
        snprintf(dest, RESULT_LENGTH, "%s", obj->name);
    } else if(t == TYPE_BOOL) {
        snprintf(dest, RESULT_LENGTH, "%s", obj->number ? "T" : "F");
    } else if(t == TYPE_ERROR) {
        snprintf(dest, RESULT_LENGTH, "E%d", obj->err);
    } else if(t == TYPE_LIST) {
        stringList(dest, obj);
    } else {
        snprintf(dest, RESULT_LENGTH, "%d", obj->number);
    }

    return dest;
}

void debugObj(const Object *obj)
{
#ifdef DEBUG
    printObj(obj);
#endif
    return;
}

void _printList(const Object *list, int newline);
void _printObj(const Object *obj, int newline)
{
    if(obj->type == TYPE_NUMBER) {
        printd("TYPE_NUMBER");
    } else if(obj->type == TYPE_BOOL) {
        printd("TYPE_BOOL");
    } else if(obj->type == TYPE_LIST) {
        printd("TYPE_LIST\n");
    } else if(obj->type == TYPE_FUNC) {
        printd("TYPE_FUNC");
    } else if(obj->type == TYPE_SYMBOL) {
        printd("TYPE_SYMBOL");
    } else if(obj->type == TYPE_LAMBDA) {
        printd("TYPE_LAMBDA Params:\n");
        printObj(&obj->lambda->params);
        printd("Lambda Body: \n");
        printObj(&obj->lambda->body);
        return;
    } else if(obj->type == TYPE_ERROR) {
        printd("TYPE_ERROR: ");
    } else {
        printd("TYPE_OTHER (as int)");
    }
    char temp[100] = "";
    stringObj(temp, obj);
    if(newline)
        printf("%s\n", temp);
    else
        printf("%s", temp);
    printErr(obj);
}

// Prints the given object
void printObj(const Object *obj)
{
    _printObj(obj, 1);
}

void _printList(const Object *list, int newline)
{
    printf("(");
    FOR_POINTER_IN_LIST(list) {
        printf(" ");
        _printObj(POINTER, 0);
    }
    printf(" )");

    if(newline)
        printf("\n");
}

void printList(const Object *list)
{
    _printList(list, 1);
}

void cleanObject(Object *target)
{
    if(target == NULL)
        return;

    const Type t = target->type;
    if(t == TYPE_LAMBDA) {
        cleanObject(&target->lambda->params);
        cleanObject(&target->lambda->body);
        free(target->lambda);
    } else if(t == TYPE_LIST) {
        deleteList(target);
    }
    target->forward = NULL;
}

void printAndClean(Object *target)
{
    printObj(target);
    cleanObject(target);
}

// Frees all objects in a list
void deleteList(Object *dest)
{
    if(!dest)
        return;

    if(dest->type != TYPE_LIST) {
        printf("Tried to delete something other than a list\n");
        return;
    }

    Object *march = dest->list;
    while(march != NULL) {
        Object *prevMarch = march;
        march = march->forward;
        cleanObject(prevMarch);
        free(prevMarch);
    }
    dest->list = NULL;
}

void _copyList(Object *dest, const Object *src, int delete) {
    if(!dest || !src) {
        printd("NULL\n");
        return;
    }
    if(dest->type != TYPE_LIST || src->type != TYPE_LIST) {
        printd("NOT A LIST\n");
        return;
    }

    if(delete)
        deleteList(dest);

    FOR_POINTER_IN_LIST(src) {
        debugObj(POINTER);
        nf_addToList(dest, *POINTER);
        if(POINTER->type == TYPE_LIST) {
            tail(dest)->list = NULL;
            _copyList(tail(dest), POINTER, 0);
        }
    }
}
/**
 * Does a deep copy of all items from `src` to `dest`
 * Does nothing if either is NULL, or not a list type
 * Deletes all items from `dest` before copying
 */
void copyList(Object *dest, const Object *src)
{
    _copyList(dest, src, 1);
}

// Returns a basic object with NULL forward and the given `type`
inline Object newObject(Type type)
{
    Object no;
    no.forward = NULL;
    no.type = type;
    return no;
}

// Returns an empty list object
inline Object listObject()
{
    Object list = newObject(TYPE_LIST);
    list.list = NULL;
    return list;
}

inline Object startList(const Object start)
{
    Object list = listObject();
    nf_addToList(&list, start);
    return list;
}

inline Object numberObject(int num)
{
    Object o = newObject(TYPE_NUMBER);
    o.number = num;
    return o;
}

inline Object boolObject(int b)
{
    Object o = newObject(TYPE_BOOL);
    o.number = b;
    return o;
}

inline Object symbolObject()
{
    return newObject(TYPE_SYMBOL);
}

inline Object lambdaObject()
{
    Object o = newObject(TYPE_LAMBDA);
    o.lambda = malloc(sizeof(struct Lambda));
    return o;
}

inline Object constructLambda(const Object *params, const Object *body)
{
    if(!params || !body)
        return errorObject(NULL_LAMBDA_LIST);

    if(params->type != TYPE_LIST || body->type != TYPE_LIST)
        return errorObject(LAMBDA_ARGS_NOT_LIST);

    Object o = lambdaObject();
    o.lambda->params = listObject();
    o.lambda->body = listObject();
    copyList(&o.lambda->params, params);
    copyList(&o.lambda->body, body);
    return o;
}

inline Object errorObject(enum errorCode err)
{
    Object o = newObject(TYPE_ERROR);
    o.err = err;
    return o;
}