CSCI-1200/hws/youtube_comments/main.cpp

#include <iostream>
#include <fstream>
#include <sstream>
#include <string>
#include <vector>
#include <map>
#include <algorithm>
#include "comment.h"

// Function to parse a string field from json line
std::string parseStringField(const std::string& json, const std::string& field) {
    std::string field_name = "\"" + field + "\": \"";
    size_t pos = json.find(field_name);
    if (pos == std::string::npos) {
        return "";
    }
    pos += field_name.length();
    size_t end = json.find("\"", pos);
    return json.substr(pos, end - pos);
}

// Function to parse a numeric field from json line
int parseNumericField(const std::string& json, const std::string& field) {
    std::string field_name = "\"" + field + "\": ";
    size_t pos = json.find(field_name);
    if (pos == std::string::npos) {
        return 0;
    }
    pos += field_name.length();
    size_t end = json.find(",", pos);
    if (end == std::string::npos) {
        end = json.find("}", pos);
    }
    return std::stoi(json.substr(pos, end - pos));
}

// Function to parse a boolean field from json line
bool parseBooleanField(const std::string& json, const std::string& field) {
    std::string field_name = "\"" + field + "\": ";
    size_t pos = json.find(field_name);
    if (pos == std::string::npos) {
        return false;
    }
    pos += field_name.length();
    return json.substr(pos, 4) == "true";
}

// Function to recursively display comments with proper indentation
void displayComment(Comment* comment, std::ofstream& output, int indent_level = 0) {
    if (comment == nullptr) {
        return;
    }
    
    // Create indentation string
    std::string indent(indent_level * 4, ' ');
    
    // Display the comment
    output << indent << comment->author << " " << comment->published_date << std::endl;
    output << indent << comment->comment << std::endl;
    output << indent << "👍 " << comment->like_count << std::endl;
    
    // Display reply count if there are replies
    // We use the original reply_count from the JSON, which includes all descendants
    if (comment->reply_count > 0) {
        if (comment->reply_count == 1) {
            output << indent << comment->reply_count << " reply" << std::endl;
        } else {
            output << indent << comment->reply_count << " replies" << std::endl;
        }
    }
    
    // Recursively display child comments with increased indentation
    for (size_t i = 0; i < comment->children.size(); ++i) {
        displayComment(comment->children[i], output, indent_level + 1);
    }
}

// Function to recursively delete a comment and all its descendants
void deleteCommentRecursive(Comment* comment, std::map<std::string, Comment*>& comment_map) {
    if (comment == nullptr) {
        return;
    }
    
    // First recursively delete all children
    for (size_t i = 0; i < comment->children.size(); ++i) {
        deleteCommentRecursive(comment->children[i], comment_map);
    }
    
    // Remove this comment from the map
    comment_map.erase(comment->comment_id);
}

// Function to read and parse the JSON file
void parseJsonFile(const std::string& jsonFile, 
                  std::map<std::string, Comment*>& comment_map,
                  std::vector<Comment*>& root_comments) {
    // Open the json file
    std::ifstream json_stream(jsonFile);
    if (!json_stream.is_open()) {
        std::cerr << "Failed to open the JSON file." << std::endl;
        exit(1);
    }
    
    // Read the entire json file into a string
    std::string json_content;
    std::string line;
    while (std::getline(json_stream, line)) {
        json_content += line;
    }
    json_stream.close();
    
    // Find all comments in the json content
    size_t pos = 0;
    while ((pos = json_content.find("{\"video_id\":", pos)) != std::string::npos) {
        // Find the end of this comment
        size_t end = json_content.find("}", pos);
        if (end == std::string::npos) break;
        end++; // Include the closing brace
        
        // Extract this comment's json string
        std::string comment_json = json_content.substr(pos, end - pos);
        
        // Parse the fields from the json
        std::string video_id = parseStringField(comment_json, "video_id");
        std::string author = parseStringField(comment_json, "author");
        std::string comment_id = parseStringField(comment_json, "comment_id");
        int like_count = parseNumericField(comment_json, "like_count");
        int reply_count = parseNumericField(comment_json, "reply_count");
        bool is_reply = parseBooleanField(comment_json, "is_reply");
        std::string parent_comment_id = parseStringField(comment_json, "parent_comment_id");
        std::string published_date = parseStringField(comment_json, "published_date");
        std::string crawled_date = parseStringField(comment_json, "crawled_date");
        bool is_video_owner = parseBooleanField(comment_json, "is_video_owner");
        std::string comment_text = parseStringField(comment_json, "comment");
        
        // Create a new Comment object
        Comment* comment = new Comment(video_id, author, comment_id, like_count, reply_count,
                                      is_reply, parent_comment_id, published_date, crawled_date,
                                      is_video_owner, comment_text);
        
        // Add to the map
        comment_map[comment_id] = comment;
        
        // Move to the next comment
        pos = end;
    }
}

// Function to build the comment tree
void buildCommentTree(std::map<std::string, Comment*>& comment_map,
                     std::vector<Comment*>& root_comments) {
    std::map<std::string, Comment*>::iterator it;
    for (it = comment_map.begin(); it != comment_map.end(); ++it) {
        Comment* comment = it->second;
        if (comment->is_reply) {
            // This comment is a reply to another comment
            std::map<std::string, Comment*>::iterator parent_it = comment_map.find(comment->parent_comment_id);
            if (parent_it != comment_map.end()) {
                parent_it->second->addChild(comment);
            }
        } else {
            // This comment is a direct response to the video
            root_comments.push_back(comment);
        }
    }
}

// Function to process a reply to video operation
void processReplyToVideo(const std::string& line, 
                        std::map<std::string, Comment*>& comment_map,
                        std::vector<Comment*>& root_comments) {
    std::istringstream iss(line);
    std::string command, comment_id, author, comment_text;
    iss >> command >> comment_id >> author;
    
    // Skip whitespace to get to the comment text
    iss >> std::ws;
    // Read the comment text (enclosed in double quotes)
    if (iss.peek() == '"') {
        iss.get(); // Consume the opening double quote
        std::getline(iss, comment_text, '"'); // Read until the closing double quote
    }
    
    // Create a new comment
    Comment* new_comment = new Comment("", author, comment_id, 0, 0, false, "", "0 seconds ago", "", false, comment_text);
    
    // Add to the map and root comments
    comment_map[comment_id] = new_comment;
    root_comments.push_back(new_comment);
}

// Function to process a reply to comment operation
void processReplyToComment(const std::string& line, 
                          std::map<std::string, Comment*>& comment_map) {
    std::istringstream iss(line);
    std::string command, parent_id, comment_id, author, comment_text;
    iss >> command >> parent_id >> comment_id >> author;
    
    // Skip whitespace to get to the comment text
    iss >> std::ws;
    // Read the comment text (enclosed in double quotes)
    if (iss.peek() == '"') {
        iss.get(); // Consume the opening double quote
        std::getline(iss, comment_text, '"'); // Read until the closing double quote
    }
    
    // Create a new comment
    Comment* new_comment = new Comment("", author, comment_id, 0, 0, true, parent_id, "0 seconds ago", "", false, comment_text);
    
    // Add to the map
    comment_map[comment_id] = new_comment;
    
    // Add as a child to the parent comment
    std::map<std::string, Comment*>::iterator parent_it = comment_map.find(parent_id);
    if (parent_it != comment_map.end()) {
        parent_it->second->addChild(new_comment);
        // Increment the parent's reply_count
        parent_it->second->reply_count++;
    }
}

// Function to process a like comment operation
void processLikeComment(const std::string& line, 
                       std::map<std::string, Comment*>& comment_map) {
    std::istringstream iss(line);
    std::string command, comment_id;
    iss >> command >> comment_id;
    
    // Like the comment
    std::map<std::string, Comment*>::iterator it = comment_map.find(comment_id);
    if (it != comment_map.end()) {
        it->second->like();
    }
}

// Function to process a delete comment operation
void processDeleteComment(const std::string& line, 
                         std::map<std::string, Comment*>& comment_map,
                         std::vector<Comment*>& root_comments) {
    std::istringstream iss(line);
    std::string command, comment_id;
    iss >> command >> comment_id;
    
    // Find the comment to delete
    std::map<std::string, Comment*>::iterator it = comment_map.find(comment_id);
    if (it != comment_map.end()) {
        Comment* comment_to_delete = it->second;
        
        // If this is a root comment, remove it from root_comments
        std::vector<Comment*>::iterator root_it = std::find(root_comments.begin(), root_comments.end(), comment_to_delete);
        if (root_it != root_comments.end()) {
            root_comments.erase(root_it);
        } else {
            // If not a root comment, remove it from its parent's children
            std::map<std::string, Comment*>::iterator parent_it = comment_map.find(comment_to_delete->parent_comment_id);
            if (parent_it != comment_map.end()) {
                std::vector<Comment*>& siblings = parent_it->second->children;
                std::vector<Comment*>::iterator sibling_it = std::find(siblings.begin(), siblings.end(), comment_to_delete);
                if (sibling_it != siblings.end()) {
                    siblings.erase(sibling_it);
                    // Decrement the parent's reply count
                    parent_it->second->reply_count--;
                }
            }
        }
        
        // Recursively delete this comment and all its descendants
        deleteCommentRecursive(comment_to_delete, comment_map);
        delete comment_to_delete;
    }
}

// Function to process a display comment operation
void processDisplayComment(const std::string& line, 
                          std::map<std::string, Comment*>& comment_map,
                          std::ofstream& output_file) {
    std::istringstream iss(line);
    std::string command, comment_id;
    iss >> command >> comment_id;
    
    // Display the comment and its descendants
    std::map<std::string, Comment*>::iterator it = comment_map.find(comment_id);
    if (it != comment_map.end()) {
        displayComment(it->second, output_file);
    }
}

// Function to process all operations from the operations file
void processOperations(const std::string& operationsFile, 
                      const std::string& outputFile,
                      std::map<std::string, Comment*>& comment_map,
                      std::vector<Comment*>& root_comments) {
    // Open the operations file
    std::ifstream ops_file(operationsFile);
    if (!ops_file.is_open()) {
        std::cerr << "Failed to open the operations file." << std::endl;
        exit(1);
    }
    
    // Open the output file
    std::ofstream output_file(outputFile);
    if (!output_file.is_open()) {
        std::cerr << "Failed to open the output file." << std::endl;
        exit(1);
    }
    
    // Process each operation in the operations file
    std::string line;
    while (std::getline(ops_file, line)) {
        std::istringstream iss(line);
        std::string command;
        iss >> command;
        
        if (command == "reply_to_video") {
            processReplyToVideo(line, comment_map, root_comments);
        }
        else if (command == "reply_to_comment") {
            processReplyToComment(line, comment_map);
        }
        else if (command == "like_comment") {
            processLikeComment(line, comment_map);
        }
        else if (command == "delete_comment") {
            processDeleteComment(line, comment_map, root_comments);
        }
        else if (command == "display_comment") {
            processDisplayComment(line, comment_map, output_file);
        }
    }
    
    // Close files
    ops_file.close();
    output_file.close();
}

// Function to clean up memory
void cleanupMemory(std::vector<Comment*>& root_comments) {
    for (size_t i = 0; i < root_comments.size(); ++i) {
        delete root_comments[i];
    }
}

int main(int argc, char* argv[]) {
    // Check if the correct number of command line arguments is provided
    if (argc != 4) {
        std::cerr << "Usage: " << argv[0] << " input1.json input2.txt output.txt" << std::endl;
        return 1;
    }
    
    // Parse command line arguments
    std::string jsonFile = argv[1];
    std::string operationsFile = argv[2];
    std::string outputFile = argv[3];
    
    // Data structures to store comments
    std::map<std::string, Comment*> comment_map; // Map comment_id to Comment
    std::vector<Comment*> root_comments; // Comments that are direct responses to the video
    
    // Parse the JSON file
    parseJsonFile(jsonFile, comment_map, root_comments);
    
    // Build the comment tree
    buildCommentTree(comment_map, root_comments);
    
    // Process operations
    processOperations(operationsFile, outputFile, comment_map, root_comments);
    
    // Clean up memory
    cleanupMemory(root_comments);
    
    return 0;
}