import os
import sys
import urllib.request
import urllib.error
import hashlib
import json
import wx
import subprocess
import time
import psutil

MAIN_APP = "YourApp.exe"

def file_hash(path):
    """
    Calculate and return the SHA-1 hash of the specified file.
    """
    h = hashlib.sha1()
    with open(path, 'rb') as f:
        while chunk := f.read(8192):
            h.update(chunk)
    return h.hexdigest()

def load_remote_manifest():
    """
    Load and return the remote manifest file as a JSON object.
    Exit the program if any network or HTTP error occurs.
    """
    try:
        with urllib.request.urlopen(MANIFEST_URL) as response:
            if response.status == 404:
                raise Exception(f"Manifest file not found: {MANIFEST_URL}")
            return json.load(response)
    except urllib.error.HTTPError as e:
        if e.code == 404:
            wx.MessageBox(f"Error 404: Manifest not found at {MANIFEST_URL}", "File Not Found", wx.OK | wx.ICON_ERROR)
        else:
            wx.MessageBox(f"HTTP error: {e.code} - {e.reason}", "HTTP Error", wx.OK | wx.ICON_ERROR)
        sys.exit(0)
    except urllib.error.URLError as e:
        wx.MessageBox(f"Network error: {str(e)}\nPlease check your internet connection and try again.", "Network Error", wx.OK | wx.ICON_ERROR)
        sys.exit(0)
    except Exception as e:
        wx.MessageBox(f"An error occurred: {str(e)}", "Error", wx.OK | wx.ICON_ERROR)
        sys.exit(0)

def download_file(filename, on_progress=None):
    """
    Download a file from the remote URL.
    Optionally updates a progress callback.
    """
    url = BASE_DOWNLOAD_URL + filename
    try:
        with urllib.request.urlopen(url) as response:
            total_size = int(response.headers.get("Content-Length", 0))
            downloaded = 0
            with open(filename, 'wb') as out_file:
                while True:
                    chunk = response.read(8192)
                    if not chunk:
                        break
                    out_file.write(chunk)
                    downloaded += len(chunk)
                    if on_progress and total_size > 0:
                        percent = int(downloaded / total_size * 100)
                        on_progress(percent)
    except urllib.error.URLError as e:
        wx.MessageBox(f"Network error: {str(e)}\nPlease check your internet connection and try again.", "Network Error", wx.OK | wx.ICON_ERROR)
        sys.exit(0)
    except Exception as e:
        wx.MessageBox(f"Download error: {str(e)}", "Download Error", wx.OK | wx.ICON_ERROR)
        sys.exit(0)

def terminate_main_app():
    """
    Terminates the main application process if it is currently running.
    """
    try:
        for proc in psutil.process_iter(['pid', 'name']):
            if proc.info['name'] and proc.info['name'].lower() == MAIN_APP.lower():
                try:
                    proc.terminate()
                    proc.wait(timeout=5)
                except psutil.NoSuchProcess:
                    pass
                except Exception as e:
                    wx.MessageBox(f"Failed to terminate {MAIN_APP}: {str(e)}", "Error", wx.OK | wx.ICON_ERROR)
                    sys.exit(0)
    except Exception as e:
        wx.MessageBox(f"Error while checking for {MAIN_APP}: {str(e)}", "Error", wx.OK | wx.ICON_ERROR)
        sys.exit(0)

class NoUpdateDialog(wx.Dialog):
    """
    Dialog shown when no update is available.
    """
    def __init__(self, parent):
        super().__init__(parent, title="Updater", size=(300, 120))
        panel = wx.Panel(self)
        vbox = wx.BoxSizer(wx.VERTICAL)
        label = wx.TextCtrl(panel,
            value="No updates available. Come back again later!",
            style=wx.TE_READONLY | wx.BORDER_NONE
        )
        label.SetBackgroundColour(panel.GetBackgroundColour())
        label.SetFont(wx.SystemSettings.GetFont(wx.SYS_DEFAULT_GUI_FONT))
        label.SetName("Update info")
        vbox.Add(label, 0, wx.ALL | wx.EXPAND, 15)
        close_btn = wx.Button(panel, label="Close")
        close_btn.Bind(wx.EVT_BUTTON, self.on_close)
        vbox.Add(close_btn, 0, wx.ALL | wx.CENTER, 10)
        panel.SetSizer(vbox)

    def on_close(self, event):
        """
        Closes the dialog when the button is clicked.
        """
        self.Close()

def get_remote_file_size(filename):
    """
    Returns the size of a remote file in bytes.
    """
    url = BASE_DOWNLOAD_URL + filename
    with urllib.request.urlopen(url) as response:
        return int(response.headers.get("Content-Length", 0))

class UpdateDialog(wx.Dialog):
    """
    Dialog that displays changelog and allows user to choose files to update.
    """
    def __init__(self, parent, changelog, files):
        super().__init__(parent, title="Update Available", size=(550, 600))
        panel = wx.Panel(self)
        vbox = wx.BoxSizer(wx.VERTICAL)

        changelog_area = wx.TextCtrl(panel, value=changelog, style=wx.TE_READONLY | wx.TE_MULTILINE, size=(500, 200))
        vbox.Add(wx.StaticText(panel, label="Changelog:"), 0, wx.ALL, 10)
        vbox.Add(changelog_area, 0, wx.ALL, 10)

        vbox.Add(wx.StaticText(panel, label="Select files to update:"), 0, wx.ALL, 10)

        filelist_box = wx.BoxSizer(wx.VERTICAL)
        self.update_checkboxes = []

        for file in files:
            size = self.format_size(get_remote_file_size(file))
            checkbox = wx.CheckBox(panel, label=file)
            checkbox.SetValue(True)
            item_hbox = wx.BoxSizer(wx.HORIZONTAL)
            item_hbox.Add(checkbox, 0, wx.ALIGN_CENTER_VERTICAL)
            item_hbox.Add(wx.StaticText(panel, label=size), 1, wx.ALIGN_CENTER_VERTICAL | wx.LEFT, 10)
            filelist_box.Add(item_hbox, 0, wx.ALL, 5)
            self.update_checkboxes.append((checkbox, file))

        vbox.Add(filelist_box, 1, wx.EXPAND | wx.ALL, 10)

        hbox = wx.BoxSizer(wx.HORIZONTAL)
        update_button = wx.Button(panel, label="&Update Now")
        update_button.Bind(wx.EVT_BUTTON, self.on_update_files)
        hbox.Add(update_button, 0, wx.ALL, 5)

        cancel_button = wx.Button(panel, label="&Cancel")
        cancel_button.Bind(wx.EVT_BUTTON, self.on_cancel)
        hbox.Add(cancel_button, 0, wx.ALL, 5)

        vbox.Add(hbox, 0, wx.ALIGN_CENTER)

        self.progress = wx.Gauge(panel, range=100, size=(500, 20))
        vbox.Add(wx.StaticText(panel, label="Progress:"), 0, wx.LEFT | wx.TOP, 10)
        vbox.Add(self.progress, 0, wx.ALL | wx.EXPAND, 10)
        panel.SetSizer(vbox)

    def format_size(self, size):
        """
        Convert a size in bytes to a human-readable string.
        """
        for unit in ['B', 'KB', 'MB', 'GB']:
            if size < 1024:
                return f"{size:.1f} {unit}"
            size /= 1024
        return f"{size:.1f} TB"

    def on_update_files(self, event):
        """
        Download selected update files and relaunch the main application.
        """
        terminate_main_app()
        try:
            for checkbox, filename in self.update_checkboxes:
                if checkbox.GetValue():
                    download_file(filename, on_progress=self.progress.SetValue)
                    self.progress.SetValue(0)
            self.Close()
            os.startfile(MAIN_APP)
            sys.exit(0)
        except Exception as e:
            wx.MessageBox(f"Update failed:\n{str(e)}", "Update Error", wx.OK | wx.ICON_ERROR)

    def on_cancel(self, event):
        """
        Cancel the update and exit the application.
        """
        self.Close()
        sys.exit(0)

def set_base_urls(base_url):
    """
    Set global URLs used for manifest, changelog, and downloads.
    """
    global BASE_URL, MANIFEST_URL, CHANGELOG_URL, BASE_DOWNLOAD_URL
    BASE_URL = base_url.rstrip('/') + '/'
    MANIFEST_URL = BASE_URL + "manifest.json"
    CHANGELOG_URL = BASE_URL + "changelog.txt"
    BASE_DOWNLOAD_URL = BASE_URL

def main():
    """
    Entry point for the updater.
    Checks for updates and launches the appropriate dialog.
    """
    if len(sys.argv) < 2:
        print("Usage: python3 updater.py <base_url>")
        sys.exit(0)

    set_base_urls(sys.argv[1])

    try:
        app = wx.App(False)
        manifest = load_remote_manifest()
        manifest.pop("manifest.json", None)

        to_update = [
            fname for fname, remote_hash in manifest.items()
            if not os.path.exists(fname) or file_hash(fname) != remote_hash
        ]

        if not to_update:
            dialog = NoUpdateDialog(None)
            dialog.ShowModal()
            dialog.Destroy()
            sys.exit(0)
        else:
            with urllib.request.urlopen(CHANGELOG_URL) as res:
                changelog = res.read().decode()
            dialog = UpdateDialog(None, changelog, to_update)
            dialog.ShowModal()

        app.MainLoop()

    except Exception as e:
        print(f"Updater Error: {e}")

if __name__ == "__main__":
    main()