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

#include "read.h"
#include "strbst.h"
#include "nodelink.h"
#include "ll.h"

static void consumespaces(FILE* file) {
    // used to consume spaces in an item ("-  list item" -> "list item")
    int c;
    while ( ( c = fgetc(file) ) != EOF && c == ' ' );
    ungetc(c, file);
}

static void wsclean(char* txt, size_t sz){ // "string\n  \n" -> "string"
    size_t i;
    for (i = sz; i > 0; i--) { // start at end [i-1] and dec
        // break on non-nl, non-space char
        if (txt[i-1] != ' ' && txt[i-1] != '\n') break;
    }
    txt[i] = 0; // finish string
}

static char* empty(void) {
    // "" with a freeable memory address
    char* str = malloc(sizeof(char));
    *str = 0;
    return str;
}

static char* getline(size_t* n, FILE* file) {
    size_t sz = 100;
    *n = 0;
    int c;
    char* out = malloc(sizeof(char)*100);
    while ( (c = fgetc(file)) != EOF ) {
        if (*n == sz) out = realloc(out, sizeof(char) * (sz *= 2));
        out[*n] = c;
        (*n)++;
        if (c == '\n') break;
    }
    out[(*n)] = 0;
    //(*n)++;
    return realloc(out, sizeof(char) * (*n+1) );
}

static char* line(FILE* file) { // gets a line from file
    size_t n;
    char* link = getline(&n, file);
        // getline stores a line of size n in link
    wsclean(link, n); // removes trailing whitespace
    if (*link == '\n') { // empty line treated as ""
        free(link);
        char* out = empty(); // DEBGUGU
        return out;
    } else { // else return obtained
        return link;
    }
}

static link* insorget(strbst* tgt, char* name) {
    link* get = query(tgt, name);
    if (!get) {
        get = newlink(newnode());
        insbst(tgt, name, get);
    }
    return get;
}

static link* addbstlink(strbst* tree, char* name, node* to) {
    link* l = newlink(to);
    insbst(tree, name, l);
    return l;
}

static char* resolvell(llnode* tail, size_t sz) {
    char *out, *pos;
    pos = out = malloc(sizeof(char)*(sz+1)); out[sz] = 0;
    while (tail != NULL) {
        size_t len = strlen(tail->str);
        memcpy(pos, tail->str, len);
        pos += len;
        llnode* tmp = tail;
        tail = tail->next;
        free(tmp->str); free(tmp);
    }
    return out;
}

node* readfile(char* name) {
    FILE* read = fopen(name, "r");
    node *root, *cur;
    cur = root = newnode();
    link* curl = addbstlink(root->links, "root", root);

    llnode start;
    start.next = NULL; // empty desc isn't undefined
    llnode *head, *tail;
    head = tail = &start;
    size_t sz = 0;

    int c;
    while ( ( c = fgetc(read) ) != EOF ) {
        if (c == ':' || c == '-') {
            curl->desc = resolvell(head->next, sz);
            head->next = NULL;
            tail = head;
            sz = 0;
            consumespaces(read);
        }
        switch (c) {
            case ':':
                curl = insorget(root->links, line(read));
                cur = curl->to;
                break;

            case '-': ;
                char* lname = line(read);
                node* at = insorget(root->links, lname)->to;
                curl = addbstlink(cur->links, lname, at);
                break;

            default:
                ungetc(c, read);
            case '.':
                tail = appendll(tail, line(read));
                sz += strlen(tail->str);
                break;
        }
    }
    fclose(read);
    return root;
}