package main

import (
	"encoding/json"
	"math/rand"
	"os"
	"path/filepath"
	"sync"
)

type Profile struct {
	UserAgent       string
	SecChUa         string
	SecChUaMobile   string
	SecChUaPlatform string
}

// SavedProfile is the captured browser fingerprint persisted after a manual
// captcha session. Reused for subsequent auto-solve attempts so VK sees a
// consistent (browser_fp, device, UA) triple rather than a freshly-generated one.
type SavedProfile struct {
	Profile
	DeviceJSON string
	BrowserFp  string
}

const profileFileName = "vk_profile.json"

var (
	profilePathOnce sync.Once
	profilePathVal  string
)

// profileFilePath returns a writeable absolute path for the cached browser
// profile. Order: $VK_PROFILE_PATH, os.UserCacheDir(), os.TempDir(), CWD.
// CWD is last because on Android it's the read-only APK lib dir.
func profileFilePath() string {
	profilePathOnce.Do(func() {
		if p := os.Getenv("VK_PROFILE_PATH"); p != "" {
			profilePathVal = p
			return
		}
		if dir, err := os.UserCacheDir(); err == nil {
			sub := filepath.Join(dir, "vk-turn-proxy")
			if mkErr := os.MkdirAll(sub, 0o755); mkErr == nil {
				profilePathVal = filepath.Join(sub, profileFileName)
				return
			}
		}
		if tmp := os.TempDir(); tmp != "" {
			profilePathVal = filepath.Join(tmp, profileFileName)
			return
		}
		profilePathVal = profileFileName
	})
	return profilePathVal
}

func LoadProfileFromDisk() (*SavedProfile, error) {
	data, err := os.ReadFile(profileFilePath())
	if err != nil {
		return nil, err
	}
	var sp SavedProfile
	if err := json.Unmarshal(data, &sp); err != nil {
		return nil, err
	}
	return &sp, nil
}

func SaveProfileToDisk(sp SavedProfile) error {
	data, err := json.MarshalIndent(sp, "", "  ")
	if err != nil {
		return err
	}
	return os.WriteFile(profileFilePath(), data, 0o644)
}

// profile contains paired User-Agent and Client Hints strings to harden bot detection.
var profile = []Profile{
	// Windows Chrome
	{
		UserAgent:       "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/146.0.0.0 Safari/537.36",
		SecChUa:         `"Chromium";v="146", "Not-A.Brand";v="24", "Google Chrome";v="146"`,
		SecChUaMobile:   "?0",
		SecChUaPlatform: `"Windows"`,
	},
	{
		UserAgent:       "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/145.0.0.0 Safari/537.36",
		SecChUa:         `"Chromium";v="145", "Not-A.Brand";v="99", "Google Chrome";v="145"`,
		SecChUaMobile:   "?0",
		SecChUaPlatform: `"Windows"`,
	},
	{
		UserAgent:       "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/144.0.0.0 Safari/537.36",
		SecChUa:         `"Chromium";v="144", "Not-A.Brand";v="8", "Google Chrome";v="144"`,
		SecChUaMobile:   "?0",
		SecChUaPlatform: `"Windows"`,
	},

	// Windows Edge
	{
		UserAgent:       "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/146.0.0.0 Safari/537.36 Edg/146.0.0.0",
		SecChUa:         `"Chromium";v="146", "Not-A.Brand";v="24", "Microsoft Edge";v="146"`,
		SecChUaMobile:   "?0",
		SecChUaPlatform: `"Windows"`,
	},
	{
		UserAgent:       "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/145.0.0.0 Safari/537.36 Edg/145.0.0.0",
		SecChUa:         `"Chromium";v="145", "Not-A.Brand";v="99", "Microsoft Edge";v="145"`,
		SecChUaMobile:   "?0",
		SecChUaPlatform: `"Windows"`,
	},

	// macOS Chrome
	{
		UserAgent:       "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/146.0.0.0 Safari/537.36",
		SecChUa:         `"Chromium";v="146", "Not-A.Brand";v="24", "Google Chrome";v="146"`,
		SecChUaMobile:   "?0",
		SecChUaPlatform: `"macOS"`,
	},
	{
		UserAgent:       "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/145.0.0.0 Safari/537.36",
		SecChUa:         `"Chromium";v="145", "Not-A.Brand";v="99", "Google Chrome";v="145"`,
		SecChUaMobile:   "?0",
		SecChUaPlatform: `"macOS"`,
	},

	// Linux Chrome
	{
		UserAgent:       "Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/146.0.0.0 Safari/537.36",
		SecChUa:         `"Chromium";v="146", "Not-A.Brand";v="24", "Google Chrome";v="146"`,
		SecChUaMobile:   "?0",
		SecChUaPlatform: `"Linux"`,
	},
	{
		UserAgent:       "Mozilla/5.0 (X11; Ubuntu; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/144.0.0.0 Safari/537.36",
		SecChUa:         `"Chromium";v="144", "Not-A.Brand";v="8", "Google Chrome";v="144"`,
		SecChUaMobile:   "?0",
		SecChUaPlatform: `"Linux"`,
	},
}

// getRandomProfile returns a paired User-Agent and Client Hints profile.
func getRandomProfile() Profile {
	return profile[rand.Intn(len(profile))]
}