<?php

function habit_update($word, $moodlog) {
   // Call habit_check_daily function
    $result = habit_check_daily($word, $moodlog);

    // Get today's date
    $todayDate = date("Y-m-d");

    // Read the existing mood log file
    $lines = file($moodlog);

    // Check if habit_check_daily returns true
    if ($result) {
        // Iterate through each line in the file
        foreach ($lines as $key => $line) {
            // Extract the date from the line
            preg_match('/(\d{4}-\d{2}-\d{2})/', $line, $match);

            if (!empty($match[1])) {
                $lineDate = $match[1];

                // Check if the line date is today
                if ($lineDate === $todayDate) {
                    // Remove the word along with the '#' symbol (case-insensitive)
                    $modifiedLine = preg_replace("/#?$word\b/i", '', $line);

                    // Remove the whole line if there is nothing after the number
                    if (preg_match('/^\d{4}-\d{2}-\d{2} \d{2}:\d{2} \[\d+\]\s*$/', $modifiedLine)) {
                        unset($lines[$key]);
                    } else {
                        $lines[$key] = $modifiedLine;
                    }
                }
            }
        }

        // Save the modified lines back to the file
        file_put_contents($moodlog, implode("", $lines));
    } else {
        $foundToday = false;

        // Check if there is a line with today's date
        foreach ($lines as $key => $line) {
            preg_match('/(\d{4}-\d{2}-\d{2})/', $line, $match);

            if (!empty($match[1]) && $match[1] === $todayDate) {
                $foundToday = true;

                // Remove the trailing newline
                $lines[$key] = rtrim($line);

                // Append #$text to the line
                $lines[$key] .= " #$word";

                // Re-add the newline
                $lines[$key] .= "\n";

                break;
            }
        }

        // If today's date is not found, prepend a new line
        if (!$foundToday) {
            // Prepend a new line with Y-m-d hh:mm [0] #$word
            $newLine = $todayDate . " " . date("H:i") . " [0] #$word\n";
            array_unshift($lines, $newLine);
        }

        // Save the modified lines back to the file
        file_put_contents($moodlog, implode("", $lines));
    }
}

function habit_cal_daily($filter){
    global $moodlog;

    $fileContent = file_get_contents($moodlog);
    $lines = explode("\n", $fileContent);
    $dateOccurrences = [];

    // Get the current date
    $currentDate = date('Y-m-d');

    foreach ($lines as $line) {
        // Extract the date from the line
        preg_match('/(\d{4}-\d{2}-\d{2})/', $line, $matches);
        $date = isset($matches[0]) ? $matches[0] : null;

        // Check if the line contains the specified word as a hashtag
        $wordFound = (strpos($line, "#$filter") !== false);

        // Populate the dateOccurrences array
        if ($date !== null) {
            // Calculate the difference in weeks
            $weekDifference = floor((strtotime($currentDate) - strtotime($date)) / (7 * 24 * 60 * 60));

            // Check if the week is more than 24 weeks ago
            if ($weekDifference > 24) {
                break;
            }

            if (!isset($dateOccurrences[$date])) {
                $dateOccurrences[$date] = 0;
            }

            if ($wordFound) {
                $dateOccurrences[$date] = 1;
            }
        }
    }

    // Remove entries with a value of 0
    $dateOccurrences = array_filter($dateOccurrences, function ($value) {
        return $value !== 0;
    });

     // Convert keys to timestamps and print in a simple JSON format with surrounding {}
    $result = '{';
    foreach ($dateOccurrences as $date => $value) {
        $timestamp = strtotime($date);
        $result .= "\"$timestamp\":$value,";
    }

    // Remove trailing comma
    $result = rtrim($result, ',');

    $result .= '}';

    echo $result;
}

function habit_cal_weekly($filter){
	global $moodlog;

	$fileContent = file_get_contents($moodlog);
    $lines = explode("\n", $fileContent);
    $dateOccurrences = [];
    $weeklyOccurrences = [];

    foreach ($lines as $line) {
        // Extract the date from the line
        preg_match('/(\b\d{4}-\d{2}-\d{2}\b)/', $line, $matches);
        $date = isset($matches[0]) ? $matches[0] : null;

        // Explode the line into words
        $words = explode(' ', $line);

        // Check if the line contains the specified word as a hashtag
        $wordFound = false;
        foreach ($words as $wordInLine) {
            // Check if the word contains "#takeout" (case-insensitive)
            if (stripos($wordInLine, "#$filter") !== false) {
                $wordFound = true;
                break;
            }
        }

        // Populate the dateOccurrences array
        if (!isset($dateOccurrences[$date])) {
                $dateOccurrences[$date] = 0;
            }
        if ($date !== null && $wordFound) {
            
            $dateOccurrences[$date]++;
        }

        // Output the line whether the word is found or not
        //echo ($wordFound) ? "+ found: $line\n" : $line . "\n";
    }

     foreach ($dateOccurrences as $date => $count) {
        // Convert each date to the format $year-$weekNo
        $dateTime = new DateTime($date);
        $yearWeek = $dateTime->format('Y-m-W');

        // Add +1 for each date converted into $year-$weekNo as a key
        if (isset($weeklyOccurrences[$yearWeek])) {
            if( $dateOccurrences[$date] == 1)
                $weeklyOccurrences[$yearWeek]++;
        } else {
            if($dateOccurrences[$date] == 1){
                $weeklyOccurrences[$yearWeek] = 1;
            }else{
                $weeklyOccurrences[$yearWeek] = 0;
            }
        }
    }

    // Remove entries with a value of 0
    $weeklyOccurrences = array_filter($weeklyOccurrences, function ($value) {
        return $value !== 0;
    });
   
    //print_r($weeklyOccurrences);

    $result = '{';
    foreach ($weeklyOccurrences as $date => $value) {
        $result .= "\"$date\":$value,";
    }
    // Remove trailing comma
    $result = rtrim($result, ',');
    $result .= '}';
    echo $result;
}

function habit_parse_file($fileContent) {
    $flattenedArray = array();

    // Split the file content into lines
    $lines = explode("\n", $fileContent);

    foreach ($lines as $line) {
        // Use regular expressions to extract relevant information
        preg_match('/\[([^\]]+)\]\[([^\]]+)\] (.+) - (.+)/', $line, $matches);

        if (count($matches) == 5) {
            $category = $matches[1];
            $value = $matches[2];
            $activity = $matches[3];
            $description = $matches[4];

            // Add to the flattened array
            $flattenedArray[] = array(
                'Category' => $category,
                'Value' => $value,
                'Activity' => $activity,
                'Description' => $description
            );
        }
    }

    return $flattenedArray;
}

function habit_check_daily($word, $filename) {
    // Split the file content into an array of lines
    $fileContent = file_get_contents($filename);
    $lines = explode("\n", $fileContent);
	$dateOccurrences = [];

    foreach ($lines as $line) {
        // Extract the date from the line
        preg_match('/(\d{4}-\d{2}-\d{2})/', $line, $matches);
        $date = isset($matches[0]) ? $matches[0] : null;

        // Check if the line contains the specified word as a hashtag
        $wordFound = (strpos($line, "#$word") !== false);

        // Populate the dateOccurrences array
        if ($date !== null) {
            if (!isset($dateOccurrences[$date])) {
                $dateOccurrences[$date] = 0;
            }
            if($wordFound){
	            $dateOccurrences[$date] = 1;
            }
        }
    }

     // Check streak
    $currentStreak = 0;
    $today = date('Y-m-d');
    //print_r($dateOccurrences);

    while (isset($dateOccurrences[$today]) && $dateOccurrences[$today] > 0) {
        $currentStreak++;
        $today = date('Y-m-d', strtotime($today . ' - 1 day'));
    }

    if( $currentStreak >= 1){
    	return true;
    }else{
    	return false;
    }
}

function habit_count_weekly($word, $filename) {
    $fileContent = file_get_contents($filename);
    $lines = explode("\n", $fileContent);
    $currentWeekNumber = (int)date("W");
    $wordCount = 0;

    foreach ($lines as $line) {
        preg_match('/^(\d{4}-\d{2}-\d{2} \d{2}:\d{2})/', $line, $matches);

        if (!empty($matches)) {
            $lineDate = new DateTime($matches[1]);
            $lineWeekNumber = (int)$lineDate->format('W');

            // Check if the line's week number is the same as the current week number
            if ($lineWeekNumber == $currentWeekNumber) {
                $wordCount += substr_count($line, "#$word");
            }
        }
    }

    return $wordCount;
}

function habit_get_stat_streak($word, $filename) {
    // Split the file content into an array of lines
    $fileContent = file_get_contents($filename);
    $lines = explode("\n", $fileContent);
	$dateOccurrences = [];

    foreach ($lines as $line) {
        // Extract the date from the line
        preg_match('/(\d{4}-\d{2}-\d{2})/', $line, $matches);
        $date = isset($matches[0]) ? $matches[0] : null;

        // Check if the line contains the specified word as a hashtag
        $wordFound = (strpos($line, "#$word") !== false);

        // Populate the dateOccurrences array
        if ($date !== null) {
            if (!isset($dateOccurrences[$date])) {
                $dateOccurrences[$date] = 0;
            }
            if($wordFound){
	            $dateOccurrences[$date] = 1;
            }
        }
    }

     // Check streak
    $currentStreak = 0;
    $today = date('Y-m-d');

    while (isset($dateOccurrences[$today]) && $dateOccurrences[$today] > 0) {
        $currentStreak++;
        $today = date('Y-m-d', strtotime($today . ' - 1 day'));
    }

    return $currentStreak;
}

function habit_get_stat_streak_week($word, $multiplier, $filename) {
    // Split the file content into an array of lines
    $fileContent = file_get_contents($filename);
    $lines = explode("\n", $fileContent);
    $dateOccurrences = [];
    $weeklyOccurrences = [];

    foreach ($lines as $line) {
	    // Extract the date from the line
	    preg_match('/(\b\d{4}-\d{2}-\d{2}\b)/', $line, $matches);
	    $date = isset($matches[0]) ? $matches[0] : null;

	    // Explode the line into words
	    $words = explode(' ', $line);

	    // Check if the line contains the specified word as a hashtag
	    $wordFound = false;
	    foreach ($words as $wordInLine) {
	        // Check if the word contains "#takeout" (case-insensitive)
	        if (stripos($wordInLine, "#$word") !== false) {
	            $wordFound = true;
	            break;
	        }
	    }

	    // Populate the dateOccurrences array
	    if ($date !== null && $wordFound) {
	        if (!isset($dateOccurrences[$date])) {
	            $dateOccurrences[$date] = 0;
	        }
	        $dateOccurrences[$date]++;
	    }

	    // Output the line whether the word is found or not
	    //echo ($wordFound) ? "+ found: $line\n" : $line . "\n";
	}

	// Output the occurrences
	//print_r($dateOccurrences);

    // Create weekly occurrences array

    foreach ($dateOccurrences as $date => $count) {
	    // Convert each date to the format $year-$weekNo
	    $dateTime = new DateTime($date);
	    $yearWeek = $dateTime->format('Y-W');

	    // Add +1 for each date converted into $year-$weekNo as a key
	    if (isset($weeklyOccurrences[$yearWeek])) {
	        $weeklyOccurrences[$yearWeek]++;
	    } else {
	        $weeklyOccurrences[$yearWeek] = 1;
	    }
	}

	
    $streak = 0;
	$thisWeek = date('Y-W'); // Get the current week

	while (isset($weeklyOccurrences[$thisWeek]) && $weeklyOccurrences[$thisWeek] >= $multiplier) {
	    $streak++;
	    $thisWeek = date('Y-W', strtotime($thisWeek . ' -1 week'));
	}

  	//print_r($dateOccurrences);
    //print_r($weeklyOccurrences);

    return $streak;
}

function habit_get_stat_missed($word, $filename) {
    // Split the file content into an array of lines
   $fileContent = file_get_contents($filename);
    $lines = explode("\n", $fileContent);

   // Set variables
    $missedDays = 0;
    $currentDate = date('Y-m-d');
    $wordFound = false;

    // Find the minimum date in the lines
    $minDate = null;
    foreach ($lines as $line) {
        preg_match('/(\d{4}-\d{2}-\d{2})/', $line, $matches);
        $date = isset($matches[0]) ? $matches[0] : null;

        if ($date !== null && ($minDate === null || $date < $minDate)) {
            $minDate = $date;
        }
    }

    // Loop for each day
    while (true) {
        // Check if the word is found on any line for the current date
        foreach ($lines as $line) {
            preg_match('/(\d{4}-\d{2}-\d{2})/', $line, $matches);
            $date = isset($matches[0]) ? $matches[0] : null;

            $wordFound = $wordFound || ($date === $currentDate && strpos($line, "#$word") !== false);
        }

        // If the word is found or we reach the beginning of the available dates, break the loop
        if ($wordFound || $currentDate < $minDate) {
            break;
        }

        // Move to the previous day
        $missedDays++;
        $currentDate = date('Y-m-d', strtotime($currentDate . ' - 1 day'));
    }

    return $wordFound ? $missedDays : 0;
}

function habit_get_stat_missed_week($word, $multiplier, $filename) {
    // Split the file content into an array of lines
    $fileContent = file_get_contents($filename);
    $lines = explode("\n", $fileContent);
    $dateOccurrences = [];
    $weeklyOccurrences = [];

    foreach ($lines as $line) {
	    // Extract the date from the line
	    preg_match('/(\b\d{4}-\d{2}-\d{2}\b)/', $line, $matches);
	    $date = isset($matches[0]) ? $matches[0] : null;

	    // Explode the line into words
	    $words = explode(' ', $line);

	    // Check if the line contains the specified word as a hashtag
	    $wordFound = false;
	    foreach ($words as $wordInLine) {
	        // Check if the word contains "#takeout" (case-insensitive)
	        if (stripos($wordInLine, "#$word") !== false) {
	            $wordFound = true;
	            break;
	        }
	    }

	    // Populate the dateOccurrences array
	    if (!isset($dateOccurrences[$date])) {
	            $dateOccurrences[$date] = 0;
	        }
	    if ($date !== null && $wordFound) {
	        
	        $dateOccurrences[$date]++;
	    }

	    // Output the line whether the word is found or not
	    //echo ($wordFound) ? "+ found: $line\n" : $line . "\n";
	}

    foreach ($dateOccurrences as $date => $count) {
	    // Convert each date to the format $year-$weekNo
	    $dateTime = new DateTime($date);
	    $yearWeek = $dateTime->format('Y-W');

	    // Add +1 for each date converted into $year-$weekNo as a key
	    if (isset($weeklyOccurrences[$yearWeek])) {
	    	if( $dateOccurrences[$date] == 1)
	        	$weeklyOccurrences[$yearWeek]++;
	    } else {
	    	if($dateOccurrences[$date] == 1){
	        	$weeklyOccurrences[$yearWeek] = 1;
	    	}else{
	    		$weeklyOccurrences[$yearWeek] = 0;
	    	}
	    }
	}

	//print_r($dateOccurrences);
    //print_r($weeklyOccurrences);

    $countZeros = 0;

	foreach ($weeklyOccurrences as $value) {
	    if ($value < $multiplier) {
	        $countZeros++;
	    } else {
	        break; // Stop counting when a non-zero value is encountered
	    }
	}
	return $countZeros;
}

function habit_get_stat_top($word, $filename) {
    $fileContent = file_get_contents($filename);

    // Split the file content into an array of lines
    $lines = explode("\n", $fileContent);

    $dateOccurrences = [];
    $currentStreak = 0;
    $longestStreak = 0;

    foreach ($lines as $line) {
        // Extract the date from the line
        preg_match('/(\d{4}-\d{2}-\d{2})/', $line, $matches);
        $date = isset($matches[0]) ? $matches[0] : null;

        // Check if the line contains the specified word as a hashtag
        $wordFound = (strpos($line, "#$word") !== false);

        // Populate the dateOccurrences array
        if ($date !== null) {
            if (!isset($dateOccurrences[$date])) {
                $dateOccurrences[$date] = 0;
            }
            if($wordFound){
	            $dateOccurrences[$date] = 1;
            }
        }
    }

    foreach ($dateOccurrences as $date => $value) {
        if ($value == 1) {
            $currentStreak++;
        } else {
            $currentStreak = 0;
        }

        // Update the longest streak if the current streak is greater
        $longestStreak = max($longestStreak, $currentStreak);
    }

    //print_r($dateOccurrences);
    return $longestStreak;
}

function habit_get_stat_top_week($word, $multiplier, $filename) {
	// Split the file content into an array of lines
    $fileContent = file_get_contents($filename);
    $lines = explode("\n", $fileContent);
    $dateOccurrences = [];
    $weeklyOccurrences = [];

    foreach ($lines as $line) {
	    // Extract the date from the line
	    preg_match('/(\b\d{4}-\d{2}-\d{2}\b)/', $line, $matches);
	    $date = isset($matches[0]) ? $matches[0] : null;

	    // Explode the line into words
	    $words = explode(' ', $line);

	    // Check if the line contains the specified word as a hashtag
	    $wordFound = false;
	    foreach ($words as $wordInLine) {
	        // Check if the word contains "#takeout" (case-insensitive)
	        if (stripos($wordInLine, "#$word") !== false) {
	            $wordFound = true;
	            break;
	        }
	    }

	    // Populate the dateOccurrences array
	    if (!isset($dateOccurrences[$date])) {
	            $dateOccurrences[$date] = 0;
	        }
	    if ($date !== null && $wordFound) {
	        
	        $dateOccurrences[$date]++;
	    }

	    // Output the line whether the word is found or not
	    //echo ($wordFound) ? "+ found: $line\n" : $line . "\n";
	}

    foreach ($dateOccurrences as $date => $count) {
	    // Convert each date to the format $year-$weekNo
	    $dateTime = new DateTime($date);
	    $yearWeek = $dateTime->format('Y-W');

	    // Add +1 for each date converted into $year-$weekNo as a key
	    if (isset($weeklyOccurrences[$yearWeek])) {
	    	if( $dateOccurrences[$date] == 1)
	        	$weeklyOccurrences[$yearWeek]++;
	    } else {
	    	if($dateOccurrences[$date] == 1){
	        	$weeklyOccurrences[$yearWeek] = 1;
	    	}else{
	    		$weeklyOccurrences[$yearWeek] = 0;
	    	}
	    }
	}

	//print_r($dateOccurrences);
    //print_r($weeklyOccurrences);

    $currentStreak = 0;
	$longestStreak = 0;

	foreach ($weeklyOccurrences as $week => $value) {
	    if ($value >= $multiplier) {
	        // Increment the streak length if the value is greater than or equal to the multiplier
	        $currentStreak++;
	    } else {
	        // Reset the streak length if the value is less than the multiplier
	        $currentStreak = 0;
	    }

	    // Update the longest streak if the current streak is longer
	    $longestStreak = max($longestStreak, $currentStreak);
	}
	return $longestStreak;
}

function habit_get_stat_top_missing($word, $filename) {
 $fileContent = file_get_contents($filename);

    // Split the file content into an array of lines
    $lines = explode("\n", $fileContent);

    // Find the earliest instance of the word
    $earliestDateWithWord = null;
    foreach ($lines as $line) {
        preg_match('/(\d{4}-\d{2}-\d{2})/', $line, $matches);
        $date = isset($matches[0]) ? $matches[0] : null;

        // Check if the line contains the specified word as a hashtag
        $wordFound = (strpos($line, "#$word") !== false);

        if ($wordFound && ($earliestDateWithWord === null || $date < $earliestDateWithWord)) {
            $earliestDateWithWord = $date;
        }
    }

    if ($earliestDateWithWord === null) {
        // No instance of the word found, return 0
        return 0;
    }

    $currentDate = $earliestDateWithWord;
    $today = date('Y-m-d');
    $dateArray = [];

    // Initialize date array with 0 values starting from the earliest date with the word
    while ($currentDate <= $today) {
        $dateArray[$currentDate] = 0;
        $currentDate = date('Y-m-d', strtotime($currentDate . ' + 1 day'));
    }

    // Loop over the file and update dateArray
    foreach ($lines as $line) {
        preg_match('/(\d{4}-\d{2}-\d{2})/', $line, $matches);
        $date = isset($matches[0]) ? $matches[0] : null;

        // Check if the line contains the specified word as a hashtag
        $wordFound = (strpos($line, "#$word") !== false);

        if ($date !== null && isset($dateArray[$date])) {
            // Update dateArray based on word occurrence
            if($wordFound)
            	$dateArray[$date] = 1;
        }
    }

    // Find the longest streak of 0's in dateArray
    $currentStreak = 0;
    $longestStreak = 0;

    foreach ($dateArray as $value) {
        if ($value === 0) {
            $currentStreak++;
        } else {
            $longestStreak = max($longestStreak, $currentStreak);
            $currentStreak = 0;
        }
    }

    return $longestStreak;
}

function habit_get_stat_year($word, $filename) {
    $fileContent = file_get_contents($filename);

    // Split the file content into an array of lines
    $lines = explode("\n", $fileContent);

    $daysWithWord = [];

    foreach ($lines as $line) {
        // Extract the date from the line
        preg_match('/(\d{4}-\d{2}-\d{2})/', $line, $matches);
        $date = isset($matches[0]) ? $matches[0] : null;

        // Check if the line contains the specified word as a hashtag
        $wordFound = (strpos($line, "#$word") !== false);

        if ($date !== null && date('Y', strtotime($date)) == date('Y')) {
            // Check if the date is in the current year
            if (!isset($daysWithWord[$date])) {
                $daysWithWord[$date] = $wordFound ? 1 : 0;
            } else {
                $daysWithWord[$date] += $wordFound ? 1 : 0;
            }
        }
    }

    $daysCount = array_sum($daysWithWord);

    return $daysCount;
}

function habit_get_json($word, $moodlog, $habitlog){
    $fileContent = file_get_contents($habitlog);
    $resultArray = habit_parse_file($fileContent);
    $found = false;

    foreach ($resultArray as $section) {
        $jsonArray = array();
        $jsonArray['align'] = "";
        $jsonArray['buttonClass'] = "";
        $jsonArray['buttonText'] = "";
        if($section['Category'][0] == "d" && $section['Activity'] == $word){
            $found = true;
            $jsonArray['freq'] = "d";

            if($section['Category'][1] == "+"){
                $jsonArray['align'] = "good";
                $jsonArray['calCol'] = "#58e81b";
                $jsonArray['title1'] = "Streak";
                $jsonArray['title2'] = "Missed";
                $jsonArray['title3'] = "Top";
                $jsonArray['result1'] = habit_get_stat_streak($section['Activity'], $moodlog);
                $jsonArray['result2'] = habit_get_stat_missed($section['Activity'], $moodlog);
                $jsonArray['result3'] = habit_get_stat_top($section['Activity'], $moodlog);

            }
            if($section['Category'][1] == "-"){
                $jsonArray['align'] = "bad";
                $jsonArray['calCol'] = "#e81b1b";
                $jsonArray['title1'] = "Streak";
                $jsonArray['title2'] = "Top";
                $jsonArray['title3'] = "Total (Year)";
                $jsonArray['result1'] = habit_get_stat_missed($section['Activity'], $moodlog);
                $jsonArray['result2'] = habit_get_stat_top_missing($section['Activity'], $moodlog);
                $jsonArray['result3'] = habit_get_stat_year($section['Activity'], $moodlog);
            }
            $todayCheck = habit_check_daily($section['Activity'], $moodlog);
            if ($todayCheck) {
                $jsonArray['buttonClass'] = 'button-'.$jsonArray['align'];
            }
            break;
        }
        if($section['Category'][0] == "w" && $section['Activity'] == $word){
            $found = true;
            $jsonArray['freq'] = "w";

            $multiplier = $section['Category'][1];
            $jsonArray['align'] = "good";
            $jsonArray['title1'] = "Streak";
            $jsonArray['title2'] = "Missed";
            $jsonArray['title3'] = "Top";
            $jsonArray['result1'] = habit_get_stat_streak_week($section['Activity'], $multiplier, $moodlog);
            $jsonArray['result2'] = habit_get_stat_missed_week($section['Activity'], $multiplier, $moodlog);
            $jsonArray['result3'] = habit_get_stat_top_week($section['Activity'], $multiplier, $moodlog);
           
            $todayCheck = habit_check_daily($section['Activity'], $moodlog);
            $weekCount = habit_count_weekly($section['Activity'], $moodlog);
            $jsonArray['weekSoFar'] = $weekCount;
            $jsonArray['weekGoal'] = $multiplier;

            if( $weekCount < $multiplier )
                if($todayCheck)
                    $jsonArray['buttonText'] = $weekCount;
            if( $todayCheck ) {
                $jsonArray['buttonClass'] = 'button-neut';
                if($weekCount >= $multiplier)
                    $jsonArray['buttonClass'] = 'button-good';
            }
            break;
        }
    }

    if($found)
        return json_encode($jsonArray);
    return false;
}

/***
 * creating calendar stuff
 */
// Function to get the ISO week numbers in a month
function getISOWeeksInMonth($year, $month) {
    $firstDay = new \DateTime("$year-$month-01");
    $lastDay = new \DateTime($firstDay->format('Y-m-t'));

    // Calculate ISO week numbers for each day
    $isoWeeks = [];
    $currentDay = clone $firstDay;

    while ($currentDay <= $lastDay) {
        $isoWeek = $currentDay->format('W');
        $isoWeeks[] = $isoWeek;
        $currentDay->modify('+1 day');
    }

    return array_unique($isoWeeks);
}

// Function to check if a date is a Sunday
function isSunday($date) {
    return $date->format('w') == 0;
}

function create_new_weekly_cal(){
    $calHTML = "";
    // Get current date
    $currentDate = new \DateTime();
    // Create an array to store months
    $months = [];

    // Loop through the current month to 23 months ago and store in the array
    for ($i = 0; $i < 23; $i++) {
        $year = $currentDate->format('Y');
        $month = $currentDate->format('m');

        // Get the ISO week numbers in the month
        $isoWeeksInMonth = getISOWeeksInMonth($year, $month);

        // Store the month data in the array
        $months[] = [
            'year' => $year,
            'month' => $month,
            'isoWeeks' => $isoWeeksInMonth,
        ];

        // Move forward one month for the next iteration
        $currentDate->sub(new DateInterval('P1M'));
    }

    // Reverse the array to display the oldest month first
    $months = array_reverse($months);

    // Create the grid
    $calHTML .= '<div class="grid-container">';

    // Loop through the months array to output the grid
    foreach ($months as $monthData) {
        $year = $monthData['year'];
        $month = $monthData['month'];
        $isoWeeksInMonth = $monthData['isoWeeks'];

        $calHTML .= '<div class="month">';
        //echo "<h3>{$year}-{$month}</h3>";
        $calHTML .= '<div class="week-container">';
        
        // Keep the last ISO week if it's December and the last day is Sunday
        if ($month === '12' && isSunday(new \DateTime("$year-$month-31"))) {
            foreach ($isoWeeksInMonth as $isoWeek) {
                $calHTML .= "<div class='week' id='{$year}-{$month}-{$isoWeek}' title='{$year}-{$month}, Week {$isoWeek}'></div>";
            }
        } else {
            // Exclude the last ISO week when outputting weeks
            $keys = array_keys($isoWeeksInMonth);
            $lastKey = end($keys);
            foreach ($isoWeeksInMonth as $isoWeekKey => $isoWeek) {
                if ($isoWeekKey === $lastKey) {
                    continue;
                }
                $calHTML .= "<div class='week' id='{$year}-{$month}-{$isoWeek}' title='{$year}-{$month}, Week {$isoWeek}'></div>";
            }
        }

        $calHTML .= '</div>';
        $calHTML .= '</div>';
    }

    $calHTML .= '</div>';
    return $calHTML;
}


?>