#include "tree_sitter/runtime.h"
#include <string.h>
#include <stdio.h>

static ts_tree * ts_tree_make(ts_symbol symbol, size_t size, size_t offset) {
    ts_tree *result = malloc(sizeof(ts_tree));
    *result = (ts_tree) {
        .ref_count = 1,
        .symbol = symbol,
        .size = size,
        .offset = offset,
    };
    return result;
}

ts_tree * ts_tree_make_leaf(ts_symbol symbol, size_t size, size_t offset) {
    ts_tree *result = ts_tree_make(symbol, size, offset);
    result->data.children.count = 0;
    result->data.children.contents = NULL;
    return result;
}

ts_tree * ts_tree_make_node(ts_symbol symbol, size_t child_count, ts_tree **children, size_t size, size_t offset) {
    for (size_t i = 0; i < child_count; i++)
        ts_tree_retain(children[i]);
    ts_tree *result = ts_tree_make(symbol, size, offset);
    result->data.children.count = child_count;
    result->data.children.contents = children;
    return result;
}

ts_tree * ts_tree_make_error(char lookahead_char, size_t expected_input_count, const ts_symbol *expected_inputs, size_t size, size_t offset) {
    ts_tree *result = ts_tree_make(ts_builtin_sym_error, size, offset);
    result->data.error.lookahead_char = lookahead_char;
    result->data.error.expected_input_count = expected_input_count;
    result->data.error.expected_inputs = expected_inputs;
    return result;
}

void ts_tree_retain(ts_tree *tree) {
    tree->ref_count++;
}

void ts_tree_release(ts_tree *tree) {
    tree->ref_count--;
    if (tree->ref_count == 0) {
        size_t count;
        ts_tree **children = ts_tree_children(tree, &count);
        for (size_t i = 0; i < count; i++)
            ts_tree_release(children[i]);
        free(children);
        free(tree);
    }
}

int ts_tree_equals(const ts_tree *node1, const ts_tree *node2) {
    if (node1->symbol != node2->symbol) return 0;
    if (node1->symbol == ts_builtin_sym_error) {
        // check error equality
    } else {
        if (node1->data.children.count != node2->data.children.count)
            return 0;
        for (size_t i = 0; i < node1->data.children.count; i++) {
            ts_tree *child1 = node1->data.children.contents[i];
            ts_tree *child2 = node2->data.children.contents[i];
            if (!ts_tree_equals(child1, child2))
                return 0;
        }
    }
    return 1;
}

ts_tree ** ts_tree_children(const ts_tree *tree, size_t *count) {
    if (tree->symbol == ts_builtin_sym_error) {
        if (count) *count = 0;
        return NULL;
    }
    if (count) *count = tree->data.children.count;
    return tree->data.children.contents;
}

static size_t tree_write_to_string(const ts_tree *tree, const char **symbol_names, char *string, size_t limit, int is_beginning) {
    char *cursor = string;
    char **destination = (limit > 0) ? &cursor : &string;
    
    if (!tree)
        return snprintf(*destination, limit, "(NULL)");

    if (!tree->is_hidden && !is_beginning)
        cursor += snprintf(*destination, limit, " ");
        
    if (tree->symbol == ts_builtin_sym_error) {
        cursor += snprintf(*destination, limit, "(ERROR)");
        return cursor - string;
    }

    if (!tree->is_hidden)
        cursor += snprintf(*destination, limit, "(%s", symbol_names[tree->symbol]);

    for (size_t i = 0; i < tree->data.children.count; i++) {
        ts_tree *child = tree->data.children.contents[i];
        cursor += tree_write_to_string(child, symbol_names, *destination, limit, 0);
    }

    if (!tree->is_hidden)
        cursor += snprintf(*destination, limit, ")");
    
    return cursor - string;
}

char * ts_tree_string(const ts_tree *tree, const char **symbol_names) {
    static char SCRATCH_STRING[100];
    size_t size = tree_write_to_string(tree, symbol_names, SCRATCH_STRING, 0, 1) + 1;
    char *result = malloc(size * sizeof(char));
    tree_write_to_string(tree, symbol_names, result, size, 1);
    return result;
}

char * ts_tree_error_string(const ts_tree *tree, const char **symbol_names) {
    return NULL;
}