// Package geminicli provides helpers for interacting with Gemini CLI tools.
package geminicli

import (
	"fmt"
	"os"
	"time"
)

const (
	AIStudioBaseURL  = "https://generativelanguage.googleapis.com"
	GeminiCliBaseURL = "https://cloudcode-pa.googleapis.com"

	AuthorizeURL = "https://accounts.google.com/o/oauth2/v2/auth"
	TokenURL     = "https://oauth2.googleapis.com/token"

	// AIStudioOAuthRedirectURI is the default redirect URI used for AI Studio OAuth.
	// This matches the "copy/paste callback URL" flow used by OpenAI OAuth in this project.
	// Note: You still need to register this redirect URI in your Google OAuth client
	// unless you use an OAuth client type that permits localhost redirect URIs.
	AIStudioOAuthRedirectURI = "http://localhost:1455/auth/callback"

	// DefaultScopes for Code Assist (includes cloud-platform for API access plus userinfo scopes)
	// Required by Google's Code Assist API.
	DefaultCodeAssistScopes = "https://www.googleapis.com/auth/cloud-platform https://www.googleapis.com/auth/userinfo.email https://www.googleapis.com/auth/userinfo.profile"

	// DefaultScopes for AI Studio (uses generativelanguage API with OAuth)
	// Reference: https://ai.google.dev/gemini-api/docs/oauth
	// For regular Google accounts, supports API calls to generativelanguage.googleapis.com
	// Note: Google Auth platform currently documents the OAuth scope as
	// https://www.googleapis.com/auth/generative-language.retriever (often with cloud-platform).
	DefaultAIStudioScopes = "https://www.googleapis.com/auth/cloud-platform https://www.googleapis.com/auth/generative-language.retriever"

	// DefaultGoogleOneScopes (DEPRECATED, no longer used)
	// Google One now always uses the built-in Gemini CLI client with DefaultCodeAssistScopes.
	// This constant is kept for backward compatibility but is not actively used.
	DefaultGoogleOneScopes = "https://www.googleapis.com/auth/cloud-platform https://www.googleapis.com/auth/generative-language.retriever https://www.googleapis.com/auth/drive.readonly https://www.googleapis.com/auth/userinfo.email https://www.googleapis.com/auth/userinfo.profile"

	// GeminiCLIRedirectURI is the redirect URI used by Gemini CLI for Code Assist OAuth.
	GeminiCLIRedirectURI = "https://codeassist.google.com/authcode"

	// GeminiCLIOAuthClientID/Secret are the public OAuth client credentials used by Google Gemini CLI.
	// They enable the "login without creating your own OAuth client" experience, but Google may
	// restrict which scopes are allowed for this client.
	GeminiCLIOAuthClientID     = "681255809395-oo8ft2oprdrnp9e3aqf6av3hmdib135j.apps.googleusercontent.com"
	GeminiCLIOAuthClientSecret = "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"

	// GeminiCLIOAuthClientSecretEnv is the environment variable name for the built-in client secret.
	GeminiCLIOAuthClientSecretEnv = "GEMINI_CLI_OAUTH_CLIENT_SECRET"

	SessionTTL = 30 * time.Minute

	// GeminiCLIUserAgent 静态回退值（不含 model）
	// 优先使用 GetGeminiCLIUserAgent(model) 获取完整格式
	GeminiCLIUserAgent = "GeminiCLI/0.33.1"

	// FakeNodeVersion 模拟真实 Gemini CLI 的 Node.js 版本
	// 用于 x-goog-api-client 和 token exchange User-Agent
	FakeNodeVersion = "24.13.1"

	// GoogleAuthLibraryUA 模拟 google-auth-library 的 User-Agent
	// 真实 Gemini CLI token exchange 由 google-auth-library 发起
	GoogleAuthLibraryUA = "google-api-nodejs-client"

	// FakePlatformOS 和 FakePlatformArch 模拟真实客户端的操作系统和架构
	// 真实 Gemini CLI 运行在用户桌面，不是 Linux 服务器
	// Node.js process.platform: darwin, linux, win32
	// Node.js process.arch: arm64, x64 (注意: Node.js 用 x64，不是 amd64)
	FakePlatformOS   = "darwin"
	FakePlatformArch = "arm64"
)

// defaultGeminiCLIVersion 可通过环境变量 GEMINI_CLI_VERSION 覆盖
var defaultGeminiCLIVersion = "0.33.1"

// defaultFakePlatformOS/Arch 可通过环境变量覆盖
var (
	defaultFakePlatformOS   = FakePlatformOS
	defaultFakePlatformArch = FakePlatformArch
)

func init() {
	if v := os.Getenv("GEMINI_CLI_VERSION"); v != "" {
		defaultGeminiCLIVersion = v
	}
	if p := os.Getenv("GEMINI_CLI_PLATFORM_OS"); p != "" {
		defaultFakePlatformOS = p
	}
	if a := os.Getenv("GEMINI_CLI_PLATFORM_ARCH"); a != "" {
		defaultFakePlatformArch = a
	}
}

// GetGeminiCLIUserAgent 返回匹配真实 Gemini CLI 格式的 User-Agent
// 真实格式: GeminiCLI/{version}/{model} ({platform}; {arch})
// 示例: GeminiCLI/0.33.1/gemini-2.5-pro (darwin; arm64)
// 注意: 不使用 runtime.GOOS/GOARCH — 服务器是 Linux，但要模拟桌面客户端
// 注意: Node.js 用 x64 不是 amd64，arm64 两者一致
func GetGeminiCLIUserAgent(model ...string) string {
	m := "unknown"
	if len(model) > 0 && model[0] != "" {
		m = model[0]
	}
	return fmt.Sprintf("GeminiCLI/%s/%s (%s; %s)",
		defaultGeminiCLIVersion, m, defaultFakePlatformOS, defaultFakePlatformArch)
}

// GetGeminiCLIGoogAPIClient 返回 x-goog-api-client 头的值
// 真实 Gemini CLI 通过 google-auth-library DefaultTransporter 自动注入:
// gl-node/{nodeVersion}
func GetGeminiCLIGoogAPIClient() string {
	return fmt.Sprintf("gl-node/%s", FakeNodeVersion)
}

// GetGeminiCLITokenExchangeUA 返回 token exchange/refresh 时的 User-Agent
// 真实 Gemini CLI 使用 google-auth-library 发起 token 交换
func GetGeminiCLITokenExchangeUA() string {
	return GoogleAuthLibraryUA
}