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

#define RESULT_LENGTH 30

#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

/**
 * 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 o_ignore, struct Environment *e_ignore)
{
    Object o = numberObject(listLength(&obj1));
    if(o.number < 0) {
        return errorObject(NOT_A_LIST);
    }
    return o;
}

/**
 * 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;

    FOR_POINTER_IN_LIST(listObj) {
        if(POINTER == NULL)
            return NULL;
        if(n-- == 0)
            return POINTER;
    }
    return NULL;
}

/**
 * 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 *tail = NULL;
    FOR_POINTER_IN_LIST(listObj) {
        tail = POINTER;
    }
    return tail;
}

/**
 * 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:
        case TYPE_STRING:
            return obj->string == NULL || obj->string[0] == '\0';
        case TYPE_FUNC:
            return obj->func == NULL;
        case TYPE_OTHER:
            return obj->other == NULL;
        case TYPE_ERROR:
            return obj->err == 0;
    }

    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, int ind, const Object src)
{
    if(!dest || dest->type != TYPE_LIST)
        return;

    // Merely append, when possible
    if(ind >= listLength(dest)) {
        nf_addToList(dest, src);
        return;
    }

    // The Objects to preceed and follow the new one
    Object *beforeNew = itemAt(dest, ind - 1);
    Object *afterNew = beforeNew->forward;

    // Replace the `before` Object's pointer
    allocObject(&beforeNew->forward, src);
    beforeNew->forward->forward = afterNew;
}

/**
 * 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);
    Object *oldForward = replace->forward;
    cleanObject(replace);
    *replace = src;
    replace->forward = oldForward;
}

/**
 * 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);
}

static const char *errorText[] = {
    "MISMATCHED_PARENS",
    "BAD_LIST_OF_SYMBOL_STRINGS",
    "TYPE_LIST_NOT_CAUGHT",
    "NULL_ENV",
    "EMPTY_ENV",
    "BUILT_IN_NOT_FOUND",
    "NULL_PARSE",
    "NULL_LAMBDA_LIST",
    "NULL_MAP_ARGS",
    "LAMBDA_ARGS_NOT_LIST",
    "DID_NOT_FIND_SYMBOL",
    "BAD_TYPE",
    "UNEXPECTED_FORM",
    "LISTS_NOT_SAME_SIZE",
    "BAD_NUMBER",
    "UNSUPPORTED_NUMBER_TYPE",
    "NOT_A_SYMBOL",
    "ONLY_ONE_ARGUMENT",
    "NOT_A_LIST",
    "SCRIPT_NOT_FOUND",
    "NO_CLONE_SPECIFIED",
    "CAN_ONLY_EVAL_STRINGS"
};

/**
 * Prints out the error of a given error Object
 * Doesn't print anything if `obj` is NULL or not an error type
 * @param obj A pointer to the Object to print
 */
void printErr(const Object *obj)
{
    if(!obj || obj->type != TYPE_ERROR)
        return;

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

/**
 * Creates a string from a given list Object
 * Blocks out with parens
 * Returns immediately if `dest` is NULL, or `obj` is not a list type
 * @param dest The string to copy the list text into
 * @param obj The list Object to make a string from
 */
void stringList(char *dest, const Object *obj)
{
    if(!dest || obj->type != TYPE_LIST)
        return;

    dest[0] = '(';
    dest[1] = '\0';

    FOR_POINTER_IN_LIST(obj) {
        strcat(dest, " ");
        char tok[90] = "";
        stringObj(tok, POINTER);
        strcat(dest, tok);
    }
    strcat(dest, " )");
}

/**
 * Creates a string from a given Object
 * Returns NULL if either param is NULL
 *
 * Prints
 * -# Numbers without spaces
 * -# Symbols as their name
 * -# Bools as 'T' or 'F'
 * -# Strings as their string value
 * -# Lists using stringList()
 * -# Errors as the integer value, prepended with 'E'
 * -# Otherwise as the raw number, prepended with 'X'
 *
 * @param dest The string to copy the list text into
 * @param obj The list Object to make a string from
 */
char* stringObj(char *dest, const Object *obj)
{
    if(!dest || !obj)
        return NULL;

    switch(obj->type) {
        case TYPE_NUMBER:
            snprintf(dest, RESULT_LENGTH, "%d", obj->number);
            break;
        case TYPE_BOOL:
            snprintf(dest, RESULT_LENGTH, "%s", obj->number ? "T" : "F");
            break;
        case TYPE_STRING:
            snprintf(dest, RESULT_LENGTH, "%s", obj->string);
            break;
        case TYPE_SYMBOL:
            snprintf(dest, RESULT_LENGTH, "`%s`", obj->string);
            break;
        case TYPE_LIST:
            stringList(dest, obj);
            break;
        case TYPE_ERROR:
            #ifdef STANDALONE
            snprintf(dest, RESULT_LENGTH, "%s", errorText[(int)(obj->err)]);
            #else
            snprintf(dest, RESULT_LENGTH, "E%d", obj->err);
            #endif
            break;
        case TYPE_FUNC:
        case TYPE_LAMBDA:
            snprintf(dest, RESULT_LENGTH, "X%d", obj->number);
            break;
        case TYPE_OTHER:
            snprintf(dest, RESULT_LENGTH, "%p", obj->other->data);
            break;
    }

    if(!isValidType(*obj))
        snprintf(dest, RESULT_LENGTH, "BAD_TYPE(%d) X%d", obj->type, obj->number);

    return dest;
}

/**
 * Prints a given Object only if the DEBUG flag is set
 * @param obj The Object to debug
 */
void debugObj(const Object *obj)
{
#ifdef DEBUG
    printObj(obj);
#endif
    return;
}

void printType(const Object *obj)
{
    switch(obj->type) {
        case TYPE_NUMBER:
            printf("TYPE_NUMBER");
            return;
        case TYPE_BOOL:
            printf("TYPE_BOOL");
            return;
        case TYPE_LIST:
            printf("TYPE_LIST");
            return;
        case TYPE_FUNC:
            printf("TYPE_FUNC");
            return;
        case TYPE_SYMBOL:
            printf("TYPE_SYMBOL");
            return;
        case TYPE_STRING:
            printf("TYPE_STRING");
            return;
        case TYPE_LAMBDA:
            printf("TYPE_LAMBDA Params:\n");
            return;
        case TYPE_OTHER:
            printf("TYPE_OTHER: ");
        case TYPE_ERROR:
            printf("TYPE_ERROR: ");
            return;
    }

    if(!isValidType(*obj))
        printf("UNKNOWN TYPE (%d)", obj->type);
}

void _printList(const Object *list, int newline);
void _printObj(const Object *obj, int newline)
{
    #ifdef DEBUG
    printType(obj);
    #endif

    if (obj->type == TYPE_LAMBDA) {
        printObj(&obj->lambda->params);
        printf("->");
        printObj(&obj->lambda->body);
        return;
    }

    char temp[100] = "";
    stringObj(temp, obj);
    if(newline)
        printf("%s\n", temp);
    else
        printf("%s", temp);
}

/**
 * Prints the given Object and a newline.
 * Uses stringObj() to create the printed string
 * If the DEBUG flag is set, the Object's type will be printed first
 * @param obj The Object to print
 */
inline 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");
}

/**
 * Prints each Object in a given list, surrounded by parentheses
 * @param list The list Object to print
 */
void printList(const Object *list)
{
    _printList(list, 1);
}

/**
 * Performs appropriate free() on a given Object and NULLs its ->forward
 * Returns immediately if param is NULL
 *
 * Strings: The Object's ->string is freed and NULLed
 * Lists: deleteList() is called on the Object (may recurse)
 * Lambdas: The body and params are cleaned, and the lambda itself is freed
 *
 * @param target The object to clean
 */
void cleanObject(Object *target)
{
    //printf("CLEANING:");
    if(target == NULL)
        return;

    switch(target->type) {
        case TYPE_STRING:
        case TYPE_SYMBOL:
            free(target->string);
            target->string = NULL;
            break;
        case TYPE_LIST:
            deleteList(target);
            break;
        case TYPE_LAMBDA:
            cleanObject(&target->lambda->params);
            cleanObject(&target->lambda->body);
            free(target->lambda);
            break;
        case TYPE_OTHER:
            if(target->other->cleanup) {
                target->other->cleanup(target);
            }
            //free(target->other);
            break;
        case TYPE_BOOL:
        case TYPE_NUMBER:
        case TYPE_FUNC:
        case TYPE_ERROR:
            break;
    }

    target->forward = NULL;
}

/**
 * Print the given object with a newline, then clean it
 * @param target The object to print and clean
 */
void printAndClean(Object *target)
{
    printObj(target);
    cleanObject(target);
}

/**
 * Frees all objects in a given list
 * Runs cleanObject() on every item in the list (may recurse)
 *
 * @param dest The list object to clean up
 */
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) {
        if(POINTER->type == TYPE_LIST) {
            nf_addToList(dest, *POINTER);
            tail(dest)->list = NULL;
            _copyList(tail(dest), POINTER, 0);
        } else if (isStringy(*POINTER)) {
            nf_addToList(dest, cloneString(*POINTER));
        } else {
            nf_addToList(dest, *POINTER);
        }
    }
}

/**
 * Does a deep copy of all items from `src` to `dest`
 * Does nothing if either param is NULL, or not a list type
 * Does a shallow delete of items from `dest` before copying
 * May recurse into lists in the list
 *
 * @param dest The list to copy to
 * @param src The list to copy from
 */
void copyList(Object *dest, const Object *src)
{
    _copyList(dest, src, 1);
}

/**
 * Does a deep copy of all items from `src` to the end of `dest`
 * Does nothing if either param is NULL, or not a list type
 * May recurse into lists in the list
 *
 * @param dest The list to copy to
 * @param src The list to copy from
 */
void appendList(Object *dest, const Object *src)
{
    _copyList(dest, src, 0);
}

/**
 * Returns a basic Object with NULL forward and the given type
 * @param type The type of Object to create
 * @return The created Object
 */
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;
}

// Returns a list Object starting with the given Object
inline Object startList(const Object start)
{
    Object list = listObject();
    nf_addToList(&list, start);
    return list;
}

inline int isStringy(const Object test)
{
    return test.type == TYPE_STRING || test.type == TYPE_SYMBOL;
}

inline int isValidType(const Object test)
{
    switch(test.type) {
        case TYPE_NUMBER:
        case TYPE_BOOL:
        case TYPE_LIST:
        case TYPE_FUNC:
        case TYPE_SYMBOL:
        case TYPE_LAMBDA:
        case TYPE_STRING:
        case TYPE_OTHER:
        case TYPE_ERROR:
            return 1;
    }

    return 0;
}

/**
 * Clones the given lambda with new allocations
 * Will behave unexpectedly if given something other than a lambda object!
 */
inline Object cloneLambda(const Object old)
{
    return constructLambda(&old.lambda->params, &old.lambda->body);
}

Object cloneString(Object obj)
{
    const char* string = obj.string;
    obj.string = malloc(sizeof(char) * (strlen(string) + 1));
    strcpy(obj.string, string);
    return obj;
}

// Returns an Object with a deep copy of the given Object
inline Object cloneList(const Object src)
{
    Object list = listObject();
    copyList(&list, &src);
    return list;
}

inline Object cloneOther(const Object src) {
    return src.other->clone?
            src.other->clone(src.other) :
            src;
}

inline Object cloneObject(const Object src)
{
    switch(src.type) {
        case TYPE_LIST:
            return cloneList(src);
        case TYPE_LAMBDA:
            return cloneLambda(src);
        case TYPE_STRING:
        case TYPE_SYMBOL:
            return cloneString(src);
        case TYPE_BOOL:
        case TYPE_NUMBER:
        case TYPE_FUNC:
        case TYPE_OTHER:
        case TYPE_ERROR:
            ; // Fall through to plain return
    }

    return src;
}

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;
}

// Skips first and last chars! Assumed to be '"'
inline Object objFromSlice(const char *string, int len)
{
    return stringFromSlice(&string[1], len - 1);
}

inline Object stringFromSlice(const char *string, int len)
{
    Object o = symFromSlice(string, len);
    o.type = TYPE_STRING;
    return o;
}

inline Object symFromSlice(const char *string, int len)
{
    Object o = newObject(TYPE_SYMBOL);
    o.string = calloc(sizeof(char), len + 1);
    strncpy(o.string, string, len);
    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 = newObject(TYPE_LAMBDA);
    o.lambda = malloc(sizeof(struct Lambda));
    o.lambda->params = listObject();
    o.lambda->body = listObject();
    copyList(&o.lambda->params, params);
    copyList(&o.lambda->body, body);
    return o;
}

inline int isError(const Object obj, const enum errorCode err)
{
    return obj.type == TYPE_ERROR && obj.err == err;
}

inline Object otherObject()
{
    Object o = newObject(TYPE_OTHER);
    o.other = malloc(sizeof(struct Other));
    return o;
}

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

inline Object toBool(const Object test)
{
    if(test.number == 0)
        return boolObject(0);
    return boolObject(1);
}