IO Module

io.stdin   -- Standard input stream
io.stdout  -- Standard output stream
io.stderr  -- Standard error stream

-- Read mode (default)
local file = io.open("data.txt", "r")
if file then
    local content = file:read("*a")
    file:close()
end

-- Write mode
local file = io.open("output.txt", "w")
if file then
    file:write("Hello, World!\n")
    file:close()
end

-- Append mode
local file = io.open("log.txt", "a")
if file then
    file:write("Log entry\n")
    file:close()
end

local file, err = io.open("nonexistent.txt", "r")
if not file then
    print("Error: " .. err)
end

local file = io.open("data.txt", "r")
io.close(file)

-- Or using file method
file:close()

-- Close default output file
io.close()

local temp = io.tmpfile()
temp:write("temporary data")
temp:seek("set", 0)  -- Rewind to beginning
local data = temp:read("*a")
temp:close()

local file = io.open("test.txt", "r")
print(io.type(file))       -- "file"
file:close()
print(io.type(file))       -- "closed file"
print(io.type("string"))   -- nil

-- Get current default input
local current = io.input()

-- Set default input to a file
io.input("input.txt")

-- Or set using a file handle
local file = io.open("data.txt", "r")
io.input(file)

-- Now io.read() reads from the default input
local line = io.read()

-- Redirect output to file
io.output("output.txt")
io.write("This goes to output.txt\n")

-- Restore stdout
io.output(io.stdout)
io.write("This goes to console\n")

-- Read a line
local line = io.read()

-- Read a number
local num = io.read("*n")

-- Read entire file
local content = io.read("*a")

-- Read specific number of characters
local chars = io.read(10)

local file = io.open("data.txt", "r")

-- Read line by line
for line in file:lines() do
    print(line)
end

-- Read entire file
file:seek("set", 0)  -- Rewind
local content = file:read("*a")

file:close()

-- Read file line by line without explicit open/close
for line in io.lines("data.txt") do
    print(line)
end

local file = io.open("data.txt", "r")
for line in file:lines() do
    print(line)
end
file:close()

io.write("Hello", " ", "World", "\n")
io.write(string.format("Number: %d\n", 42))

local file = io.open("output.txt", "w")
file:write("Line 1\n")
file:write("Line 2\n")
file:close()

io.write("Buffered data")
io.flush()  -- Ensure it's written immediately

local file = io.open("log.txt", "a")
file:write("Important log entry\n")
file:flush()  -- Ensure it's written to disk

local file = io.open("data.txt", "r")

-- Get current position
local pos = file:seek()

-- Seek to beginning
file:seek("set", 0)

-- Seek relative to current position
file:seek("cur", 10)

-- Seek to end
file:seek("end", 0)

file:close()

function readFile(filename)
    local file = io.open(filename, "r")
    if not file then
        return nil, "Could not open file"
    end
    
    local content = file:read("*a")
    file:close()
    return content
end

local content, err = readFile("data.txt")
if content then
    print(content)
else
    print("Error: " .. err)
end

function writeFile(filename, content)
    local file = io.open(filename, "w")
    if not file then
        return false, "Could not open file"
    end
    
    file:write(content)
    file:close()
    return true
end

local ok, err = writeFile("output.txt", "Hello, World!\n")
if not ok then
    print("Error: " .. err)
end

function appendLog(filename, message)
    local file = io.open(filename, "a")
    if file then
        file:write(os.date("%Y-%m-%d %H:%M:%S"), " - ", message, "\n")
        file:close()
    end
end

appendLog("app.log", "Application started")

function processFile(filename)
    local lineCount = 0
    local wordCount = 0
    
    for line in io.lines(filename) do
        lineCount = lineCount + 1
        for word in string.gmatch(line, "%S+") do
            wordCount = wordCount + 1
        end
    end
    
    return lineCount, wordCount
end

local lines, words = processFile("document.txt")
print(string.format("Lines: %d, Words: %d", lines, words))

function copyFile(source, dest)
    local input = io.open(source, "rb")
    if not input then
        return false, "Cannot open source file"
    end
    
    local output = io.open(dest, "wb")
    if not output then
        input:close()
        return false, "Cannot create destination file"
    end
    
    local content = input:read("*a")
    output:write(content)
    
    input:close()
    output:close()
    return true
end

function readCSV(filename)
    local rows = {}
    for line in io.lines(filename) do
        local row = {}
        for field in string.gmatch(line, '([^,]+)') do
            table.insert(row, field)
        end
        table.insert(rows, row)
    end
    return rows
end

using SolarSharp.Interpreter;
using SolarSharp.Interpreter.Modules;

// Enable IO module
var script = new Script(CoreModules.Preset_Default);

// Configure custom streams
script.Options.Stdin = myInputStream;
script.Options.Stdout = myOutputStream;
script.Options.Stderr = myErrorStream;

local file, err = io.open("missing.txt", "r")
if not file then
    print("Error: " .. err)  -- "missing.txt: No such file or directory"
end