-- Paths for the log and file list
local logFilePath = "/disk/check_log.txt"
local fileListPath = "/disk/file_list.txt"

-- Function to write to the log file
local function log(message)
    local logFile = fs.open(logFilePath, "a")
    if logFile then
        logFile.writeLine(message)
        logFile.close()
    else
        print("Error: Could not open log file.")
    end
end

-- Function to record a file path into the file list
local function recordFile(filePath)
    local fileList = fs.open(fileListPath, "a")
    if fileList then
        fileList.writeLine(filePath)
        fileList.close()
    else
        print("Error: Could not open file list.")
    end
end

-- Function to check if a file exists and is readable
local function checkFile(filePath)
    if not fs.exists(filePath) then
        local msg = "Error: File does not exist " .. filePath
        print(msg)
        log(msg)
        return false
    end

    local file = fs.open(filePath, "r")
    if not file then
        local msg = "Error: Could not open file " .. filePath
        print(msg)
        log(msg)
        return false
    end

    local success, errorMessage = pcall(function()
        local content = file.readAll()
        file.close()
    end)

    if not success then
        local msg = "Error reading file " .. filePath .. ": " .. errorMessage
        print(msg)
        log(msg)
        return false
    end

    local msg = "File " .. filePath .. " is okay."
    print(msg)
    log(msg)
    return true
end

-- Function to recursively check files in a directory, excluding /disk/users subdirectories
local function checkDirectory(directory)
    local files = fs.list(directory)
    for _, file in ipairs(files) do
        local filePath = directory .. "/" .. file
        if fs.isDir(filePath) then
            -- Skip /disk/users subdirectories
            if not filePath:match("^/disk/users") then
                checkDirectory(filePath)
            end
        else
            recordFile(filePath)  -- Record the file in the file list
            checkFile(filePath)
        end
    end
end

-- Function to check files from the recorded file list
local function checkRecordedFiles()
    if fs.exists(fileListPath) then
        local fileList = fs.open(fileListPath, "r")
        if fileList then
            for line in fileList.readLine do
                checkFile(line)
                os.sleep(0.5)  -- Reduced delay for faster processing
            end
            fileList.close()
        else
            print("Error: Could not open file list for reading.")
        end
    else
        print("No previous file list found. Scanning all files...")
        os.sleep(1)  -- Longer delay before starting full scan
        checkDirectory("/disk")
    end
end

-- Function to update references in the script
local function updateDirectoryReferences(oldDir, newDir)
    local function replaceInFile(filePath)
        local file = fs.open(filePath, "r")
        if not file then
            print("Error: Could not open file for reading " .. filePath)
            return
        end

        local content = file.readAll()
        file.close()

        local updatedContent = content:gsub(oldDir, newDir)
        if updatedContent ~= content then
            local updatedFile = fs.open(filePath, "w")
            if updatedFile then
                updatedFile.write(updatedContent)
                updatedFile.close()
                print("Updated file: " .. filePath)
            else
                print("Error: Could not open file for writing " .. filePath)
            end
        end
    end

    local function updateInDirectory(directory)
        local files = fs.list(directory)
        for _, file in ipairs(files) do
            local filePath = directory .. "/" .. file
            if fs.isDir(filePath) then
                updateInDirectory(filePath)
            else
                replaceInFile(filePath)
            end
        end
    end

    updateInDirectory("/disk")
end

-- Function to ask for new main directory and update code references
local function promptAndUpdate()
    print("Current main directory is /disk")
    write("Enter new main directory (e.g., /example): ")
    local newDir = read()

    -- Validate and format new directory
    if not newDir:match("^/") then
        newDir = "/" .. newDir
    end
    if not newDir:match("/$") then
        newDir = newDir .. "/"
    end

    print("Updating references from /disk to " .. newDir .. "...")
    updateDirectoryReferences("/disk", newDir)
    print("References updated.")
end

-- Main program
print("Starting file check...")
log("Starting file check...")

-- Prompt user to update the main directory
promptAndUpdate()

-- Clear previous log file if it exists
if fs.exists(logFilePath) then
    fs.delete(logFilePath)
end

-- Clear previous file list if it exists
if fs.exists(fileListPath) then
    fs.delete(fileListPath)
end

-- Include 'startup' and 'no-os' in the file list
recordFile("/disk/startup")
recordFile("/disk/no-os")

-- Start checking files
checkDirectory("/disk")

print("File check complete.")
log("File check complete.")