package browser

import (
	"context"
	"fmt"
	"os"
	"path/filepath"
	"runtime"
	"time"

	"github.com/chromedp/cdproto/network"
	"github.com/chromedp/chromedp"

	"git.davoryn.de/calic/claude-statusline/internal/config"
)

// LoginAndGetSessionKey opens a browser window for the user to log in to
// claude.ai and extracts the httpOnly sessionKey cookie via DevTools protocol.
// The browser uses a persistent profile so the user only needs to log in once.
// Returns the session key or an error (e.g. timeout after 2 minutes).
func LoginAndGetSessionKey() (string, error) {
	execPath := findBrowserExec()

	profileDir := filepath.Join(config.ConfigDir(), "browser-profile")
	if err := os.MkdirAll(profileDir, 0o755); err != nil {
		return "", fmt.Errorf("create browser profile dir: %w", err)
	}

	opts := append(chromedp.DefaultExecAllocatorOptions[:],
		chromedp.Flag("headless", false),
		chromedp.UserDataDir(profileDir),
	)
	if execPath != "" {
		opts = append(opts, chromedp.ExecPath(execPath))
	}

	allocCtx, allocCancel := chromedp.NewExecAllocator(context.Background(), opts...)
	defer allocCancel()

	ctx, cancel := chromedp.NewContext(allocCtx)
	defer cancel()

	// Navigate to login page
	if err := chromedp.Run(ctx, chromedp.Navigate("https://claude.ai/login")); err != nil {
		return "", fmt.Errorf("navigate to login: %w", err)
	}

	// Poll for the sessionKey cookie (httpOnly, so only accessible via DevTools)
	deadline := time.Now().Add(2 * time.Minute)
	ticker := time.NewTicker(500 * time.Millisecond)
	defer ticker.Stop()

	for {
		select {
		case <-ticker.C:
			if time.Now().After(deadline) {
				return "", fmt.Errorf("login timed out after 2 minutes")
			}

			var cookies []*network.Cookie
			if err := chromedp.Run(ctx, chromedp.ActionFunc(func(ctx context.Context) error {
				var err error
				cookies, err = network.GetCookies().Do(ctx)
				return err
			})); err != nil {
				// Browser may have been closed by user
				return "", fmt.Errorf("get cookies: %w", err)
			}

			for _, c := range cookies {
				if c.Name == "sessionKey" && (c.Domain == ".claude.ai" || c.Domain == "claude.ai") {
					key := c.Value
					if err := config.SetSessionKey(key); err != nil {
						return "", fmt.Errorf("save session key: %w", err)
					}
					// Use chromedp.Cancel to close gracefully (flushes cookies to profile)
					cancel()
					return key, nil
				}
			}
		}
	}
}

// findBrowserExec returns the path to a Chromium-based browser, or "" to let
// chromedp use its default detection (Chrome/Chromium on PATH).
func findBrowserExec() string {
	if runtime.GOOS == "windows" {
		// Prefer Edge (pre-installed on Windows 10+)
		candidates := []string{
			filepath.Join(os.Getenv("ProgramFiles(x86)"), "Microsoft", "Edge", "Application", "msedge.exe"),
			filepath.Join(os.Getenv("ProgramFiles"), "Microsoft", "Edge", "Application", "msedge.exe"),
		}
		for _, p := range candidates {
			if _, err := os.Stat(p); err == nil {
				return p
			}
		}
	}
	// On Linux/macOS, chromedp auto-detects Chrome/Chromium
	return ""
}