// Package claude provides constants and helpers for Claude API integration.
package claude

import (
	"fmt"
	"os"
	"strings"
)

// Claude Code 客户端相关常量

// DefaultCLIVersion 是当前模拟的 Claude CLI 版本
var (
	DefaultCLIVersion              = "2.1.104"
	DefaultStainlessLang           = "js"
	DefaultStainlessPackageVersion = "0.81.0"
	DefaultStainlessOS             = "MacOS"
	DefaultStainlessArch           = "arm64"
	DefaultStainlessRuntime        = "node"
	DefaultStainlessRuntimeVersion = "v24.3.0"
	DefaultStainlessRetryCount     = "0"
	DefaultStainlessTimeout        = "600"
	DefaultXApp                    = "cli"
	DefaultAnthropicVersion        = "2023-06-01"
)

// DeviceProfile 表示一组 Claude Code 客户端设备画像默认值。
type DeviceProfile struct {
	UserAgent               string
	StainlessLang           string
	StainlessPackageVersion string
	StainlessOS             string
	StainlessArch           string
	StainlessRuntime        string
	StainlessRuntimeVersion string
	StainlessRetryCount     string
	StainlessTimeout        string
	XApp                    string
	AnthropicVersion        string
}

func trimEnv(key string) string {
	return strings.TrimSpace(os.Getenv(key))
}

func envTruthy(key string) bool {
	switch strings.ToLower(trimEnv(key)) {
	case "1", "true", "yes", "on":
		return true
	default:
		return false
	}
}

func envExplicitFalse(key string) bool {
	switch strings.ToLower(trimEnv(key)) {
	case "0", "false", "no", "off":
		return true
	default:
		return false
	}
}

// CurrentEntrypoint returns the Claude Code entrypoint label used by the real CLI.
// The local bundle defaults to "cli" when CLAUDE_CODE_ENTRYPOINT is not set.
func CurrentEntrypoint() string {
	if entrypoint := trimEnv("CLAUDE_CODE_ENTRYPOINT"); entrypoint != "" {
		return entrypoint
	}
	return "cli"
}

func currentAgentSDKVersion() string {
	return trimEnv("CLAUDE_AGENT_SDK_VERSION")
}

func currentClientApp() string {
	return trimEnv("CLAUDE_AGENT_SDK_CLIENT_APP")
}

// CurrentWorkload returns the process-scoped workload tag used for cc_workload attribution.
// Local Claude Code keeps this in-process; sub2api exposes an env fallback so the server can
// mirror cron/daemon callers when configured.
func CurrentWorkload() string {
	return trimEnv("CLAUDE_CODE_WORKLOAD")
}

func currentCLIUserAgentDescriptors() []string {
	parts := []string{CurrentEntrypoint()}
	if sdkVersion := currentAgentSDKVersion(); sdkVersion != "" {
		parts = append(parts, "agent-sdk/"+sdkVersion)
	}
	if clientApp := currentClientApp(); clientApp != "" {
		parts = append(parts, "client-app/"+clientApp)
	}
	if workload := CurrentWorkload(); workload != "" {
		parts = append(parts, "workload/"+workload)
	}
	return parts
}

func currentCodeUserAgentDescriptors() []string {
	parts := make([]string, 0, 3)
	if entrypoint := trimEnv("CLAUDE_CODE_ENTRYPOINT"); entrypoint != "" {
		parts = append(parts, entrypoint)
	}
	if sdkVersion := currentAgentSDKVersion(); sdkVersion != "" {
		parts = append(parts, "agent-sdk/"+sdkVersion)
	}
	if clientApp := currentClientApp(); clientApp != "" {
		parts = append(parts, "client-app/"+clientApp)
	}
	return parts
}

func formatUserAgent(cliVersion string) string {
	version := strings.TrimSpace(cliVersion)
	if version == "" {
		version = DefaultCLIVersion
	}
	return fmt.Sprintf("claude-cli/%s (external, %s)", version, strings.Join(currentCLIUserAgentDescriptors(), ", "))
}

func DefaultUserAgent() string {
	return formatUserAgent(DefaultCLIVersion)
}

func DefaultCodeUserAgent() string {
	return "claude-code/" + strings.TrimSpace(DefaultCLIVersion)
}

// DetailedCodeUserAgent mirrors the local JqH() builder, which appends entrypoint / agent-sdk /
// client-app descriptors when they are present in the process environment.
func DetailedCodeUserAgent() string {
	version := strings.TrimSpace(DefaultCLIVersion)
	if version == "" {
		version = "unknown"
	}
	parts := currentCodeUserAgentDescriptors()
	if len(parts) == 0 {
		return "claude-code/" + version
	}
	return fmt.Sprintf("claude-code/%s (%s)", version, strings.Join(parts, ", "))
}

// DefaultDeviceProfile 返回当前默认 Claude Code 设备画像。
func DefaultDeviceProfile() DeviceProfile {
	return DeviceProfile{
		UserAgent:               DefaultUserAgent(),
		StainlessLang:           DefaultStainlessLang,
		StainlessPackageVersion: DefaultStainlessPackageVersion,
		StainlessOS:             DefaultStainlessOS,
		StainlessArch:           DefaultStainlessArch,
		StainlessRuntime:        DefaultStainlessRuntime,
		StainlessRuntimeVersion: DefaultStainlessRuntimeVersion,
		StainlessRetryCount:     DefaultStainlessRetryCount,
		StainlessTimeout:        DefaultStainlessTimeout,
		XApp:                    DefaultXApp,
		AnthropicVersion:        DefaultAnthropicVersion,
	}
}

func buildDefaultHeaders(profile DeviceProfile) map[string]string {
	return map[string]string{
		// Keep these in sync with recent Claude CLI traffic to reduce the chance
		// that Claude Code-scoped OAuth credentials are rejected as "non-CLI" usage.
		"User-Agent":                                profile.UserAgent,
		"X-Stainless-Lang":                          profile.StainlessLang,
		"X-Stainless-Package-Version":               profile.StainlessPackageVersion,
		"X-Stainless-OS":                            profile.StainlessOS,
		"X-Stainless-Arch":                          profile.StainlessArch,
		"X-Stainless-Runtime":                       profile.StainlessRuntime,
		"X-Stainless-Runtime-Version":               profile.StainlessRuntimeVersion,
		"X-Stainless-Retry-Count":                   profile.StainlessRetryCount,
		"X-Stainless-Timeout":                       profile.StainlessTimeout,
		"X-App":                                     profile.XApp,
		"anthropic-version":                         profile.AnthropicVersion,
		"anthropic-dangerous-direct-browser-access": "true",
	}
}

// DefaultHeadersSnapshot returns a fresh copy of the default Claude Code header skeleton.
// It re-evaluates env-backed runtime values like CLAUDE_CODE_ENTRYPOINT on each call.
func DefaultHeadersSnapshot() map[string]string {
	return buildDefaultHeaders(DefaultDeviceProfile())
}

// OptionalAPIHeaders returns the local Claude Code env-driven optional headers that are only
// attached in remote / SDK / protected modes.
func OptionalAPIHeaders() map[string]string {
	headers := map[string]string{}
	if containerID := trimEnv("CLAUDE_CODE_CONTAINER_ID"); containerID != "" {
		headers["x-claude-remote-container-id"] = containerID
	}
	if remoteSessionID := trimEnv("CLAUDE_CODE_REMOTE_SESSION_ID"); remoteSessionID != "" {
		headers["x-claude-remote-session-id"] = remoteSessionID
	}
	if clientApp := currentClientApp(); clientApp != "" {
		headers["x-client-app"] = clientApp
	}
	if envTruthy("CLAUDE_CODE_ADDITIONAL_PROTECTION") {
		headers["x-anthropic-additional-protection"] = "true"
	}
	return headers
}

// AttributionHeaderDisabled mirrors the official CLAUDE_CODE_ATTRIBUTION_HEADER=false toggle.
func AttributionHeaderDisabled() bool {
	return envExplicitFalse("CLAUDE_CODE_ATTRIBUTION_HEADER")
}

// Beta header 常量
//
// 这里的常量对齐真实 Claude Code CLI 的最新流量（截至 2026-04）。
// 选型参考：与 Parrot (src/transform/cc_mimicry.py) 的 BETAS 保持一致，
// 原因：Anthropic 上游会基于 anthropic-beta 的完整集合判定请求来源；
// 缺少任何"官方 Claude Code 请求才会带"的 beta，都会被降级到第三方额度，
// 对应报错：`Third-party apps now draw from your extra usage, not your plan limits.`
const (
	BetaOAuth                    = "oauth-2025-04-20"
	BetaClaudeCode               = "claude-code-20250219"
	BetaInterleavedThinking      = "interleaved-thinking-2025-05-14"
	BetaFineGrainedToolStreaming = "fine-grained-tool-streaming-2025-05-14"
	BetaTokenCounting            = "token-counting-2024-11-01"
	BetaContext1M                = "context-1m-2025-08-07"
	BetaFastMode                 = "fast-mode-2026-02-01"
	// 新增（对齐官方 CLI 2.1.9x 以来的流量）
	BetaPromptCachingScope  = "prompt-caching-scope-2026-01-05"
	BetaEffort              = "effort-2025-11-24"
	BetaRedactThinking      = "redact-thinking-2026-02-12"
	BetaContextManagement   = "context-management-2025-06-27"
	BetaExtendedCacheTTL    = "extended-cache-ttl-2025-04-11"
	BetaTaskBudgets         = "task-budgets-2026-03-13"
	BetaTokenEfficientTools = "token-efficient-tools-2026-03-28"
	BetaStructuredOutputs   = "structured-outputs-2025-12-15"
	BetaAdvisor             = "advisor-tool-2026-03-01"
	BetaWebSearch           = "web-search-2025-03-05"
)

// DroppedBetas 是转发时需要从 anthropic-beta header 中移除的 beta token 列表。
// 这些 token 是客户端特有的，不应透传给上游 API。
var DroppedBetas = []string{}

// DefaultBetaHeader Claude Code 客户端默认的 anthropic-beta header（OAuth 账号，不含 context-1m）
// 使用 GetOAuthBetaHeader(modelID) 获取含 context-1m 的 model-aware 版本。
const DefaultBetaHeader = BetaClaudeCode + "," + BetaOAuth + "," + BetaInterleavedThinking + "," + BetaFineGrainedToolStreaming + "," + BetaRedactThinking + "," + BetaContextManagement + "," + BetaPromptCachingScope + "," + BetaEffort

// MessageBetaHeaderNoTools /v1/messages 在无工具时的 beta header（OAuth，不含 context-1m）
//
// NOTE: Claude Code OAuth credentials are scoped to Claude Code. When we "mimic"
// Claude Code for non-Claude-Code clients, we must include the claude-code beta
// even if the request doesn't use tools, otherwise upstream may reject the
// request as a non-Claude-Code API request.
const MessageBetaHeaderNoTools = BetaClaudeCode + "," + BetaOAuth + "," + BetaInterleavedThinking + "," + BetaRedactThinking + "," + BetaContextManagement + "," + BetaPromptCachingScope + "," + BetaEffort

// MessageBetaHeaderWithTools /v1/messages 在有工具时的 beta header（OAuth，不含 context-1m）
const MessageBetaHeaderWithTools = BetaClaudeCode + "," + BetaOAuth + "," + BetaInterleavedThinking + "," + BetaRedactThinking + "," + BetaContextManagement + "," + BetaPromptCachingScope + "," + BetaEffort

// CountTokensBetaHeader count_tokens 请求使用的 anthropic-beta header
const CountTokensBetaHeader = BetaClaudeCode + "," + BetaOAuth + "," + BetaInterleavedThinking + "," + BetaTokenCounting + "," + BetaContextManagement

// HaikuBetaHeader Haiku 模型使用的 anthropic-beta header（OAuth，不含 claude-code / context-1m）
const HaikuBetaHeader = BetaOAuth + "," + BetaInterleavedThinking + "," + BetaEffort

// APIKeyBetaHeader API-key 账号使用的 anthropic-beta header（不含 oauth / context-1m）
// 使用 GetAPIKeyBetaHeader(modelID) 获取含 context-1m 的 model-aware 版本。
const APIKeyBetaHeader = BetaClaudeCode + "," + BetaInterleavedThinking + "," + BetaFineGrainedToolStreaming + "," + BetaEffort + "," + BetaPromptCachingScope

// APIKeyHaikuBetaHeader Haiku 模型在 API-key 账号下使用的 anthropic-beta header（不含 oauth / claude-code）
const APIKeyHaikuBetaHeader = BetaInterleavedThinking + "," + BetaEffort

// ModelSupports1M 判断模型是否支持 1M context window。
// 与 claude-code-2.1.104 bundle 中 modelSupports1M 逻辑保持一致：
//
//	claude-sonnet-4 系列 和 claude-opus-4-6 支持 1M context。
func ModelSupports1M(modelID string) bool {
	lower := strings.ToLower(strings.TrimSpace(modelID))
	return strings.Contains(lower, "claude-sonnet-4") || strings.Contains(lower, "opus-4-6")
}

// GetOAuthBetaHeader 返回 OAuth 账号的 beta header。
// 仅当模型支持 1M context 时才包含 context-1m-2025-08-07。
func GetOAuthBetaHeader(modelID string) string {
	if ModelSupports1M(modelID) {
		return BetaClaudeCode + "," + BetaOAuth + "," + BetaInterleavedThinking + "," + BetaFineGrainedToolStreaming + "," + BetaContext1M + "," + BetaRedactThinking + "," + BetaContextManagement + "," + BetaPromptCachingScope + "," + BetaEffort
	}
	return DefaultBetaHeader
}

// GetAPIKeyBetaHeader 返回 API-key 账号的 beta header。
// 仅当模型支持 1M context 时才包含 context-1m-2025-08-07。
func GetAPIKeyBetaHeader(modelID string) string {
	if strings.Contains(strings.ToLower(modelID), "haiku") {
		return APIKeyHaikuBetaHeader
	}
	if ModelSupports1M(modelID) {
		return BetaClaudeCode + "," + BetaInterleavedThinking + "," + BetaFineGrainedToolStreaming + "," + BetaContext1M + "," + BetaEffort + "," + BetaPromptCachingScope
	}
	return APIKeyBetaHeader
}

// DefaultCacheControlTTL 是网关代理为自己生成的 cache_control 块默认使用的 ttl。
// 真实 Claude Code CLI 当前使用 "1h"，但本仓策略是"客户端透传 ttl 优先；
// 客户端缺省时统一使用 5m"，这样既不浪费 1h 缓存额度，也保留客户端自定义能力。
const DefaultCacheControlTTL = "5m"

// CLICurrentVersion 是 sub2api 当前对外伪装的 Claude Code CLI 版本号（三段 semver）。
// 用于 billing attribution block 中的 cc_version=X.Y.Z.{fp} 前缀以及 fingerprint 计算。
// 必须与 DefaultHeaders["User-Agent"] 中的版本号严格一致；不一致会被 Anthropic 判第三方。
const CLICurrentVersion = "2.1.92"

// FullClaudeCodeMimicryBetas 返回最"像"真实 Claude Code CLI 的完整 beta 列表，
// 用于 OAuth 账号伪装成 Claude Code 时使用。
// 顺序与真实 CLI 抓包一致。
//
// 使用建议：
//   - OAuth 账号 + 非 haiku：追加这整份列表，再按需保留 client 带来的 beta。
//   - OAuth 账号 + haiku：Anthropic 对 haiku 不做 third-party 判定，使用 HaikuBetaHeader 即可。
//   - API-key 账号：不要使用本函数，参见 APIKeyBetaHeader。
func FullClaudeCodeMimicryBetas() []string {
	return []string{
		BetaClaudeCode,
		BetaOAuth,
		BetaInterleavedThinking,
		BetaPromptCachingScope,
		BetaEffort,
		BetaRedactThinking,
		BetaContextManagement,
		BetaExtendedCacheTTL,
	}
}

// DefaultHeaders 是 Claude Code 客户端默认请求头。
var DefaultHeaders = map[string]string{
	// Keep these in sync with recent Claude CLI traffic to reduce the chance
	// that Claude Code-scoped OAuth credentials are rejected as "non-CLI" usage.
	// 版本参考：对齐 Parrot (src/transform/cc_mimicry.py:49) 的 CLI_USER_AGENT。
	"User-Agent":                                "claude-cli/2.1.92 (external, cli)",
	"X-Stainless-Lang":                          "js",
	"X-Stainless-Package-Version":               "0.70.0",
	"X-Stainless-OS":                            "Linux",
	"X-Stainless-Arch":                          "arm64",
	"X-Stainless-Runtime":                       "node",
	"X-Stainless-Runtime-Version":               "v24.13.0",
	"X-Stainless-Retry-Count":                   "0",
	"X-Stainless-Timeout":                       "600",
	"X-App":                                     "cli",
	"Anthropic-Dangerous-Direct-Browser-Access": "true",
}

// Model 表示一个 Claude 模型
type Model struct {
	ID          string `json:"id"`
	Type        string `json:"type"`
	DisplayName string `json:"display_name"`
	CreatedAt   string `json:"created_at"`
}

// DefaultModels Claude Code 客户端支持的默认模型列表
var DefaultModels = []Model{
	{
		ID:          "claude-opus-4-5-20251101",
		Type:        "model",
		DisplayName: "Claude Opus 4.5",
		CreatedAt:   "2025-11-01T00:00:00Z",
	},
	{
		ID:          "claude-opus-4-6",
		Type:        "model",
		DisplayName: "Claude Opus 4.6",
		CreatedAt:   "2026-02-06T00:00:00Z",
	},
	{
		ID:          "claude-opus-4-7",
		Type:        "model",
		DisplayName: "Claude Opus 4.7",
		CreatedAt:   "2026-04-17T00:00:00Z",
	},
	{
		ID:          "claude-sonnet-4-6",
		Type:        "model",
		DisplayName: "Claude Sonnet 4.6",
		CreatedAt:   "2026-02-18T00:00:00Z",
	},
	{
		ID:          "claude-sonnet-4-5-20250929",
		Type:        "model",
		DisplayName: "Claude Sonnet 4.5",
		CreatedAt:   "2025-09-29T00:00:00Z",
	},
	{
		ID:          "claude-haiku-4-5-20251001",
		Type:        "model",
		DisplayName: "Claude Haiku 4.5",
		CreatedAt:   "2025-10-01T00:00:00Z",
	},
}

// DefaultModelIDs 返回默认模型的 ID 列表
func DefaultModelIDs() []string {
	ids := make([]string, len(DefaultModels))
	for i, m := range DefaultModels {
		ids[i] = m.ID
	}
	return ids
}

// DefaultTestModel 测试时使用的默认模型
const DefaultTestModel = "claude-sonnet-4-5-20250929"

// ModelIDOverrides Claude OAuth 请求需要的模型 ID 映射
var ModelIDOverrides = map[string]string{
	"claude-sonnet-4-5": "claude-sonnet-4-5-20250929",
	"claude-opus-4-5":   "claude-opus-4-5-20251101",
	"claude-haiku-4-5":  "claude-haiku-4-5-20251001",
}

// ModelIDReverseOverrides 用于将上游模型 ID 还原为短名
var ModelIDReverseOverrides = map[string]string{
	"claude-sonnet-4-5-20250929": "claude-sonnet-4-5",
	"claude-opus-4-5-20251101":   "claude-opus-4-5",
	"claude-haiku-4-5-20251001":  "claude-haiku-4-5",
}

// NormalizeModelID 根据 Claude OAuth 规则映射模型
func NormalizeModelID(id string) string {
	if id == "" {
		return id
	}
	if mapped, ok := ModelIDOverrides[id]; ok {
		return mapped
	}
	return id
}

// DenormalizeModelID 将上游模型 ID 转换为短名
func DenormalizeModelID(id string) string {
	if id == "" {
		return id
	}
	if mapped, ok := ModelIDReverseOverrides[id]; ok {
		return mapped
	}
	return id
}

// ApplyFingerprintOverrides 用配置覆盖默认指纹值（每个实例可设不同值）
func ApplyFingerprintOverrides(cliVersion, pkgVersion, runtimeVersion, os_, arch string) {
	if cliVersion != "" {
		DefaultCLIVersion = strings.TrimSpace(cliVersion)
	}
	if pkgVersion != "" {
		DefaultStainlessPackageVersion = strings.TrimSpace(pkgVersion)
	}
	if runtimeVersion != "" {
		DefaultStainlessRuntimeVersion = strings.TrimSpace(runtimeVersion)
	}
	if os_ != "" {
		DefaultStainlessOS = strings.TrimSpace(os_)
	}
	if arch != "" {
		DefaultStainlessArch = strings.TrimSpace(arch)
	}
	DefaultHeaders = buildDefaultHeaders(DefaultDeviceProfile())
}