package cmd

import (
	"fmt"
	"net/http"
	"os"
	"os/exec"
	"path/filepath"
	"runtime"
	"strings"
	"time"

	"browseros-cli/output"

	"github.com/fatih/color"
	"github.com/spf13/cobra"
)

// macOS bundle identifier — verified from BrowserOS.app/Contents/Info.plist
const browserOSBundleID = "com.browseros.BrowserOS"

func init() {
	cmd := &cobra.Command{
		Use:   "launch",
		Short: "Launch the BrowserOS application",
		Long: `Find and launch the BrowserOS application.

Uses platform-native detection to find BrowserOS, launches it,
and waits for the server to become ready.

If BrowserOS is already running, reports the server URL.`,
		Annotations: map[string]string{"group": "Setup:"},
		Args:        cobra.NoArgs,
		Run: func(cmd *cobra.Command, args []string) {
			green := color.New(color.FgGreen)
			dim := color.New(color.Faint)
			waitSecs, _ := cmd.Flags().GetInt("wait")

			if url := probeRunningServer(); url != "" {
				green.Printf("BrowserOS is already running at %s\n", url)
				return
			}

			if !isBrowserOSInstalled() {
				output.Error("BrowserOS is not installed.\n\n"+
					"  To install:  browseros-cli install", 1)
			}

			fmt.Println("Launching BrowserOS...")
			if err := startBrowserOS(); err != nil {
				output.Errorf(1, "failed to launch: %v", err)
			}

			fmt.Print("Waiting for server")
			url, ok := waitForServer(time.Duration(waitSecs) * time.Second)
			fmt.Println()

			if !ok {
				output.Error("BrowserOS launched but server didn't respond within "+
					fmt.Sprintf("%d seconds.\n", waitSecs)+
					"  Check if BrowserOS is fully loaded, then retry.", 1)
			}

			green.Printf("BrowserOS is ready at %s\n", url)
			fmt.Println()
			dim.Println("Next: browseros-cli init --auto")
		},
	}

	cmd.Flags().Int("wait", 30, "Seconds to wait for server to start")
	rootCmd.AddCommand(cmd)
}

// ---------------------------------------------------------------------------
// Server probing
// ---------------------------------------------------------------------------

// probeRunningServer checks server.json, config, and common ports for a running server.
func probeRunningServer() string {
	check := func(baseURL string) bool {
		client := &http.Client{Timeout: 2 * time.Second}
		resp, err := client.Get(baseURL + "/health")
		if err != nil {
			return false
		}
		resp.Body.Close()
		return resp.StatusCode == 200
	}

	// 1. server.json — written by BrowserOS on startup with the actual port
	if url := loadBrowserosServerURL(); url != "" && check(url) {
		return url
	}

	// 2. Saved config / env var
	if url := defaultServerURL(); url != "" && check(url) {
		return url
	}

	// 3. Probe common BrowserOS ports as last resort
	for _, port := range []int{9100, 9200, 9300} {
		url := fmt.Sprintf("http://127.0.0.1:%d", port)
		if check(url) {
			return url
		}
	}

	return ""
}

// ---------------------------------------------------------------------------
// Platform-native installation detection
// ---------------------------------------------------------------------------

// isBrowserOSInstalled checks if BrowserOS is installed using platform-native methods.
//
// macOS:   `open -Ra "BrowserOS"` — queries Launch Services (finds apps anywhere)
// Linux:   checks /usr/bin/browseros (.deb), browseros.desktop, or AppImage files
// Windows: checks executable at %LOCALAPPDATA%\BrowserOS\Application\BrowserOS.exe
//          and registry uninstall key (per-user Chromium install pattern)
func isBrowserOSInstalled() bool {
	switch runtime.GOOS {
	case "darwin":
		// open -Ra checks if Launch Services knows about the app without launching it.
		// Works regardless of where the app is installed.
		return exec.Command("open", "-Ra", "BrowserOS").Run() == nil

	case "linux":
		// .deb install puts `browseros` in /usr/bin/
		if _, err := exec.LookPath("browseros"); err == nil {
			return true
		}
		// .deb also creates browseros.desktop
		for _, dir := range []string{
			"/usr/share/applications",
			filepath.Join(userHomeDir(), ".local/share/applications"),
		} {
			if _, err := os.Stat(filepath.Join(dir, "browseros.desktop")); err == nil {
				return true
			}
		}
		// AppImage — user may have it in ~/Downloads, ~/Applications, etc.
		return findLinuxAppImage() != ""

	case "windows":
		// Chromium per-user install: %LOCALAPPDATA%\BrowserOS\Application\BrowserOS.exe
		if exePath := windowsBrowserOSExe(); exePath != "" {
			if _, err := os.Stat(exePath); err == nil {
				return true
			}
		}
		// Fallback: check uninstall registry (per-user install uses HKCU)
		for _, root := range []string{"HKCU", "HKLM"} {
			key := root + `\Software\Microsoft\Windows\CurrentVersion\Uninstall\BrowserOS`
			if exec.Command("reg", "query", key, "/v", "DisplayName").Run() == nil {
				return true
			}
		}
		return false
	}

	return false
}

// ---------------------------------------------------------------------------
// Platform-native launch
// ---------------------------------------------------------------------------

// startBrowserOS launches BrowserOS using platform-native methods.
//
// macOS:   `open -b com.browseros.BrowserOS` — launches by bundle ID
// Linux:   runs `browseros` binary or AppImage directly
// Windows: runs BrowserOS.exe from the known install path
func startBrowserOS() error {
	switch runtime.GOOS {
	case "darwin":
		// Launch by bundle ID via Launch Services — no hardcoded paths needed.
		return exec.Command("open", "-b", browserOSBundleID).Run()

	case "linux":
		// .deb install: browseros is in PATH
		if p, err := exec.LookPath("browseros"); err == nil {
			return startDetached(p)
		}
		// AppImage: run it directly
		if appImage := findLinuxAppImage(); appImage != "" {
			return startDetached(appImage)
		}
		// .desktop file: use gtk-launch (not xdg-open, which opens by MIME type)
		if _, err := exec.LookPath("gtk-launch"); err == nil {
			return exec.Command("gtk-launch", "browseros").Run()
		}
		return fmt.Errorf("BrowserOS found but could not determine how to launch it")

	case "windows":
		if exePath := windowsBrowserOSExe(); exePath != "" {
			if _, err := os.Stat(exePath); err == nil {
				return startDetached(exePath)
			}
		}
		return fmt.Errorf("BrowserOS.exe not found at expected location")

	default:
		return fmt.Errorf("unsupported platform: %s", runtime.GOOS)
	}
}

// ---------------------------------------------------------------------------
// Helpers
// ---------------------------------------------------------------------------

// startDetached starts a process in the background without inheriting stdio.
func startDetached(path string, args ...string) error {
	cmd := exec.Command(path, args...)
	cmd.Stdout = nil
	cmd.Stderr = nil
	cmd.Stdin = nil
	return cmd.Start()
}

// windowsBrowserOSExe returns the expected BrowserOS.exe path on Windows.
// Chromium per-user installs go to %LOCALAPPDATA%\<base_app_name>\Application\<binary>.
// base_app_name = "BrowserOS" (from chromium_install_modes.h)
func windowsBrowserOSExe() string {
	localAppData := os.Getenv("LOCALAPPDATA")
	if localAppData == "" {
		return ""
	}
	return filepath.Join(localAppData, "BrowserOS", "Application", "BrowserOS.exe")
}

// findLinuxAppImage searches common locations for a BrowserOS AppImage.
func findLinuxAppImage() string {
	home := userHomeDir()
	if home == "" {
		return ""
	}
	for _, dir := range []string{
		home,
		filepath.Join(home, "Applications"),
		filepath.Join(home, "Downloads"),
		"/opt",
	} {
		entries, err := os.ReadDir(dir)
		if err != nil {
			continue
		}
		for _, e := range entries {
			name := e.Name()
			if strings.HasPrefix(name, "BrowserOS") && strings.HasSuffix(name, ".AppImage") {
				return filepath.Join(dir, name)
			}
		}
	}
	return ""
}

// userHomeDir returns the home directory or empty string.
func userHomeDir() string {
	home, err := os.UserHomeDir()
	if err != nil {
		return ""
	}
	return home
}

// waitForServer polls until a BrowserOS server responds or timeout.
func waitForServer(maxWait time.Duration) (string, bool) {
	client := &http.Client{Timeout: 2 * time.Second}
	deadline := time.Now().Add(maxWait)

	for time.Now().Before(deadline) {
		// server.json is written by BrowserOS on startup with the actual port
		if url := loadBrowserosServerURL(); url != "" {
			resp, err := client.Get(url + "/health")
			if err == nil {
				resp.Body.Close()
				if resp.StatusCode == 200 {
					return url, true
				}
			}
		}
		fmt.Print(".")
		time.Sleep(1 * time.Second)
	}
	return "", false
}