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

#ifndef STANDALONE
#define printf(...) stringObj(NULL, NULL)
#endif

int listLength(const Object *listObj)
{
    if(!listObj || listObj->type != TYPE_LIST)
        return -1;

    Object *t = listObj->list;
    if(t == NULL)
        return 0;

    int len = 1;
    while(t->forward != NULL) {
        t = t->forward;
        len++;
    }
    return len;
}

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++) {
        march = march->forward;

        if(march == NULL)
            return NULL;
    }
    return march;
}

// Returns last object in list (->forward == NULL)
Object *tail(const Object *listObj)
{
    if(!listObj || listObj->type != TYPE_LIST)
        return NULL;

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

// Adds an object to the end of a list object
void addToList(Object *dest, const Object src)
{
    if(!dest || dest->type != TYPE_LIST)
        return;

    if(dest->list == NULL) {
        dest->list = malloc(sizeof(struct Object));
        *dest->list = src;
        dest->list->forward = NULL;
        return;
    }

    Object *end = tail(dest);
    end->forward = malloc(sizeof(struct Object));
    *end->forward = src;
    end->forward->forward = NULL;
}

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

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

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

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

    return dest;
}

int depth = 0;

// Prints the given object
void printObj(const Object *obj)
{
    for(int i = 0; i < depth; i++)
        printf("  ");
    depth++;

    if(obj->type == TYPE_NUMBER) {
        printf("TYPE_NUMBER");
    } else if(obj->type == TYPE_BOOL) {
        printf("TYPE_BOOL");
    } else if(obj->type == TYPE_LIST) {
        printf("TYPE_LIST\n");
        printList(obj);
        depth--;
        return;
    } else if(obj->type == TYPE_FUNC) {
        printf("TYPE_FUNC");
    } else if(obj->type == TYPE_SYMBOL) {
        printf("TYPE_SYMBOL");
    } else if(obj->type == TYPE_LAMBDA) {
        printf("TYPE_LAMBDA Params:\n");
        depth++;
        printObj(&obj->lambda->params);
        for(int i = 1; i < depth; i++)
            printf("  ");
        printf("Lambda Body: \n");
        printObj(&obj->lambda->body);
    } else if(obj->type == TYPE_ERROR) {
        printf("TYPE_ERROR: ");
    } else {
        printf("TYPE_OTHER (as int)");
    }
    depth--;
    char temp[20] = "";
    stringObj(temp, obj);
    printf(": %s\n", temp);
    printErr(obj);
}

void printList(const Object *list)
{
    const Object *tail = list->list;
    if(tail == NULL) {
        for(int i = 0; i < depth; i++)
            printf("  ");
        printf("EMPTY LIST\n");
        return;
    }
    while(tail != NULL) {
        depth++;
        printObj(tail);
        depth--;
        tail = tail->forward;
    }
}

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

    const Type t = target->type;
    if(t == TYPE_LAMBDA) {
        free(target->lambda);
    } else if(t == TYPE_LIST) {
        deleteList(target);
    }
}

// Frees all objects in a list
void deleteList(const Object *dest)
{
    if(dest->type != TYPE_LIST) {
        printf("Tried to delete something other than a list\n");
        return;
    }

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

void copyList(Object *dest, const Object *src)
{
    if(!dest || !src || dest->type != TYPE_LIST || src->type != TYPE_LIST)
        return;

    deleteList(dest);
    const Object *march = src->list;
    while(march != NULL) {
        addToList(dest, *march);
        march = march->forward;
    }
}

inline Object newObject(Type type)
{
    Object no;
    no.forward = NULL;
    no.type = type;
    return no;
}

inline Object listObject()
{
    Object list = newObject(TYPE_LIST);
    list.list = NULL;
    return list;
}

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

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

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;
}