//! Codex (OpenAI) Provider Adapter
//!
//! 仅透传模式，支持直连 OpenAI API
//!
//! ## 客户端检测
//! 支持检测官方 Codex 客户端 (codex_vscode, codex_cli_rs)

use super::{AuthInfo, AuthStrategy, ProviderAdapter};
use crate::provider::Provider;
use crate::proxy::error::ProxyError;
use regex::Regex;
use serde_json::Value as JsonValue;
use std::sync::LazyLock;
use toml::Value as TomlValue;

/// 官方 Codex 客户端 User-Agent 正则
#[allow(dead_code)]
static CODEX_CLIENT_REGEX: LazyLock<Regex> =
    LazyLock::new(|| Regex::new(r"^(codex_vscode|codex_cli_rs)/[\d.]+").unwrap());

/// Codex 适配器
pub struct CodexAdapter;

/// Local model written into Codex config.toml for Chat-only upstreams.
///
/// Codex itself must see a model it can load metadata for; the real provider
/// model is restored inside the proxy immediately before Chat Completions
/// conversion.
pub const CODEX_CHAT_CLIENT_MODEL: &str = "gpt-5.4";

/// Whether this Codex provider's real upstream should be called through
/// OpenAI Chat Completions, even if the local Codex client is talking to CC
/// Switch through the Responses API.
pub fn codex_provider_uses_chat_completions(provider: &Provider) -> bool {
    if let Some(api_format) = provider
        .meta
        .as_ref()
        .and_then(|meta| meta.api_format.as_deref())
        .or_else(|| {
            provider
                .settings_config
                .get("api_format")
                .and_then(|v| v.as_str())
        })
        .or_else(|| {
            provider
                .settings_config
                .get("apiFormat")
                .and_then(|v| v.as_str())
        })
    {
        return is_chat_wire_api(api_format);
    }

    if let Some(wire_api) = provider
        .settings_config
        .get("config")
        .and_then(|v| v.as_str())
        .and_then(extract_codex_wire_api_from_toml)
    {
        return is_chat_wire_api(&wire_api);
    }

    if let Some(base_url) = provider
        .settings_config
        .get("base_url")
        .or_else(|| provider.settings_config.get("baseURL"))
        .and_then(|v| v.as_str())
    {
        return is_chat_completions_url(base_url);
    }

    provider
        .settings_config
        .get("config")
        .and_then(|v| v.as_str())
        .and_then(extract_codex_base_url_from_toml)
        .map(|url| is_chat_completions_url(&url))
        .unwrap_or(false)
}

pub fn should_convert_codex_responses_to_chat(provider: &Provider, endpoint: &str) -> bool {
    let path = endpoint
        .split_once('?')
        .map_or(endpoint, |(path, _query)| path);

    matches!(
        path,
        "/responses" | "/v1/responses" | "/responses/compact" | "/v1/responses/compact"
    ) && codex_provider_uses_chat_completions(provider)
}

/// Extract the real upstream model configured for a Codex provider.
pub fn codex_provider_upstream_model(provider: &Provider) -> Option<String> {
    provider
        .settings_config
        .get("model")
        .and_then(|v| v.as_str())
        .map(str::trim)
        .filter(|model| !model.is_empty())
        .map(ToString::to_string)
        .or_else(|| {
            provider
                .settings_config
                .get("config")
                .and_then(|v| v.as_str())
                .and_then(extract_codex_model_from_toml)
        })
}

/// For Codex Chat providers, replace the local Codex-safe model with the real
/// upstream model before converting the request to Chat Completions.
pub fn apply_codex_chat_upstream_model(
    provider: &Provider,
    body: &mut JsonValue,
) -> Option<String> {
    if !codex_provider_uses_chat_completions(provider) {
        return None;
    }

    let upstream_model = codex_provider_upstream_model(provider)?;
    body["model"] = JsonValue::String(upstream_model.clone());
    Some(upstream_model)
}

fn is_chat_wire_api(value: &str) -> bool {
    matches!(
        value.trim().to_ascii_lowercase().as_str(),
        "chat"
            | "chat_completions"
            | "chat-completions"
            | "openai_chat"
            | "openai-chat"
            | "openai_chat_completions"
    )
}

fn is_chat_completions_url(value: &str) -> bool {
    value
        .trim_end_matches('/')
        .to_ascii_lowercase()
        .ends_with("/chat/completions")
}

fn extract_codex_wire_api_from_toml(config_text: &str) -> Option<String> {
    let doc = config_text.parse::<TomlValue>().ok()?;

    if let Some(active_provider) = doc.get("model_provider").and_then(|v| v.as_str()) {
        if let Some(wire_api) = doc
            .get("model_providers")
            .and_then(|providers| providers.get(active_provider))
            .and_then(|provider| provider.get("wire_api"))
            .and_then(|v| v.as_str())
        {
            return Some(wire_api.to_string());
        }
    }

    doc.get("wire_api")
        .and_then(|v| v.as_str())
        .map(ToString::to_string)
}

fn extract_codex_model_from_toml(config_text: &str) -> Option<String> {
    let doc = config_text.parse::<TomlValue>().ok()?;

    doc.get("model")
        .and_then(|v| v.as_str())
        .map(str::trim)
        .filter(|model| !model.is_empty())
        .map(ToString::to_string)
}

fn extract_codex_base_url_from_toml(config_text: &str) -> Option<String> {
    let doc = config_text.parse::<TomlValue>().ok()?;

    if let Some(active_provider) = doc.get("model_provider").and_then(|v| v.as_str()) {
        if let Some(base_url) = doc
            .get("model_providers")
            .and_then(|providers| providers.get(active_provider))
            .and_then(|provider| provider.get("base_url"))
            .and_then(|v| v.as_str())
        {
            return Some(base_url.to_string());
        }
    }

    doc.get("base_url")
        .and_then(|v| v.as_str())
        .map(ToString::to_string)
}

impl CodexAdapter {
    pub fn new() -> Self {
        Self
    }

    /// 检测是否为官方 Codex 客户端
    ///
    /// 匹配 User-Agent 模式: `^(codex_vscode|codex_cli_rs)/[\d.]+`
    #[allow(dead_code)]
    pub fn is_official_client(user_agent: &str) -> bool {
        CODEX_CLIENT_REGEX.is_match(user_agent)
    }

    /// 从 Provider 配置中提取 API Key
    fn extract_key(&self, provider: &Provider) -> Option<String> {
        // 1. 尝试从 env 中获取
        if let Some(env) = provider.settings_config.get("env") {
            if let Some(key) = env.get("OPENAI_API_KEY").and_then(|v| v.as_str()) {
                return Some(key.to_string());
            }
        }

        // 2. 尝试从 auth 中获取 (Codex CLI 格式)
        if let Some(auth) = provider.settings_config.get("auth") {
            if let Some(key) = auth.get("OPENAI_API_KEY").and_then(|v| v.as_str()) {
                return Some(key.to_string());
            }
        }

        // 3. 尝试直接获取
        if let Some(key) = provider
            .settings_config
            .get("apiKey")
            .or_else(|| provider.settings_config.get("api_key"))
            .and_then(|v| v.as_str())
        {
            return Some(key.to_string());
        }

        // 4. 尝试从 config 对象中获取
        if let Some(config) = provider.settings_config.get("config") {
            if let Some(key) = config
                .get("api_key")
                .or_else(|| config.get("apiKey"))
                .and_then(|v| v.as_str())
            {
                return Some(key.to_string());
            }
        }

        None
    }
}

impl Default for CodexAdapter {
    fn default() -> Self {
        Self::new()
    }
}

impl ProviderAdapter for CodexAdapter {
    fn name(&self) -> &'static str {
        "Codex"
    }

    fn extract_base_url(&self, provider: &Provider) -> Result<String, ProxyError> {
        // 1. 尝试直接获取 base_url 字段
        if let Some(url) = provider
            .settings_config
            .get("base_url")
            .and_then(|v| v.as_str())
        {
            return Ok(url.trim_end_matches('/').to_string());
        }

        // 2. 尝试 baseURL
        if let Some(url) = provider
            .settings_config
            .get("baseURL")
            .and_then(|v| v.as_str())
        {
            return Ok(url.trim_end_matches('/').to_string());
        }

        // 3. 尝试从 config 对象中获取
        if let Some(config) = provider.settings_config.get("config") {
            if let Some(url) = config.get("base_url").and_then(|v| v.as_str()) {
                return Ok(url.trim_end_matches('/').to_string());
            }

            // 尝试解析 TOML 字符串格式
            if let Some(config_str) = config.as_str() {
                if let Some(start) = config_str.find("base_url = \"") {
                    let rest = &config_str[start + 12..];
                    if let Some(end) = rest.find('"') {
                        return Ok(rest[..end].trim_end_matches('/').to_string());
                    }
                }
                if let Some(start) = config_str.find("base_url = '") {
                    let rest = &config_str[start + 12..];
                    if let Some(end) = rest.find('\'') {
                        return Ok(rest[..end].trim_end_matches('/').to_string());
                    }
                }
            }
        }

        Err(ProxyError::ConfigError(
            "Codex Provider 缺少 base_url 配置".to_string(),
        ))
    }

    fn extract_auth(&self, provider: &Provider) -> Option<AuthInfo> {
        self.extract_key(provider)
            .map(|key| AuthInfo::new(key, AuthStrategy::Bearer))
    }

    fn build_url(&self, base_url: &str, endpoint: &str) -> String {
        let base_trimmed = base_url.trim_end_matches('/');
        let endpoint_trimmed = endpoint.trim_start_matches('/');

        // OpenAI/Codex 的 base_url 可能是：
        // - 纯 origin: https://api.openai.com  (需要自动补 /v1)
        // - 已含 /v1: https://api.openai.com/v1 (直接拼接)
        // - 自定义前缀: https://xxx/openai (不添加 /v1，直接拼接)

        // 检查 base_url 是否已经包含 /v1
        let already_has_v1 = base_trimmed.ends_with("/v1");

        // 检查是否是纯 origin（没有路径部分）
        let origin_only = match base_trimmed.split_once("://") {
            Some((_scheme, rest)) => !rest.contains('/'),
            None => !base_trimmed.contains('/'),
        };

        let mut url = if already_has_v1 {
            // 已经有 /v1，直接拼接
            format!("{base_trimmed}/{endpoint_trimmed}")
        } else if origin_only {
            // 纯 origin，添加 /v1
            format!("{base_trimmed}/v1/{endpoint_trimmed}")
        } else {
            // 自定义前缀，不添加 /v1，直接拼接
            format!("{base_trimmed}/{endpoint_trimmed}")
        };

        // 去除重复的 /v1/v1（可能由 base_url 与 endpoint 都带版本导致）
        while url.contains("/v1/v1") {
            url = url.replace("/v1/v1", "/v1");
        }

        url
    }

    fn get_auth_headers(
        &self,
        auth: &AuthInfo,
    ) -> Result<Vec<(http::HeaderName, http::HeaderValue)>, ProxyError> {
        use super::adapter::auth_header_value;
        let bearer = format!("Bearer {}", auth.api_key);
        Ok(vec![(
            http::HeaderName::from_static("authorization"),
            auth_header_value(&bearer)?,
        )])
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use serde_json::json;

    fn create_provider(config: serde_json::Value) -> Provider {
        Provider {
            id: "test".to_string(),
            name: "Test Codex".to_string(),
            settings_config: config,
            website_url: None,
            category: Some("codex".to_string()),
            created_at: None,
            sort_index: None,
            notes: None,
            meta: None,
            icon: None,
            icon_color: None,
            in_failover_queue: false,
        }
    }

    #[test]
    fn test_extract_base_url_direct() {
        let adapter = CodexAdapter::new();
        let provider = create_provider(json!({
            "base_url": "https://api.openai.com/v1"
        }));

        let url = adapter.extract_base_url(&provider).unwrap();
        assert_eq!(url, "https://api.openai.com/v1");
    }

    #[test]
    fn test_extract_auth_from_auth_field() {
        let adapter = CodexAdapter::new();
        let provider = create_provider(json!({
            "auth": {
                "OPENAI_API_KEY": "sk-test-key-12345678"
            }
        }));

        let auth = adapter.extract_auth(&provider).unwrap();
        assert_eq!(auth.api_key, "sk-test-key-12345678");
        assert_eq!(auth.strategy, AuthStrategy::Bearer);
    }

    #[test]
    fn test_extract_auth_from_env() {
        let adapter = CodexAdapter::new();
        let provider = create_provider(json!({
            "env": {
                "OPENAI_API_KEY": "sk-env-key-12345678"
            }
        }));

        let auth = adapter.extract_auth(&provider).unwrap();
        assert_eq!(auth.api_key, "sk-env-key-12345678");
    }

    #[test]
    fn test_build_url() {
        let adapter = CodexAdapter::new();
        let url = adapter.build_url("https://api.openai.com/v1", "/responses");
        assert_eq!(url, "https://api.openai.com/v1/responses");
    }

    #[test]
    fn test_build_url_origin_adds_v1() {
        let adapter = CodexAdapter::new();
        let url = adapter.build_url("https://api.openai.com", "/responses");
        assert_eq!(url, "https://api.openai.com/v1/responses");
    }

    #[test]
    fn test_build_url_custom_prefix_no_v1() {
        let adapter = CodexAdapter::new();
        let url = adapter.build_url("https://example.com/openai", "/responses");
        assert_eq!(url, "https://example.com/openai/responses");
    }

    #[test]
    fn test_build_url_dedup_v1() {
        let adapter = CodexAdapter::new();
        // base_url 已包含 /v1，endpoint 也包含 /v1
        let url = adapter.build_url("https://www.packyapi.com/v1", "/v1/responses");
        assert_eq!(url, "https://www.packyapi.com/v1/responses");
    }

    // 官方客户端检测测试
    #[test]
    fn test_is_official_client_vscode() {
        assert!(CodexAdapter::is_official_client("codex_vscode/1.0.0"));
        assert!(CodexAdapter::is_official_client("codex_vscode/2.3.4"));
        assert!(CodexAdapter::is_official_client("codex_vscode/0.1"));
    }

    #[test]
    fn test_is_official_client_cli() {
        assert!(CodexAdapter::is_official_client("codex_cli_rs/1.0.0"));
        assert!(CodexAdapter::is_official_client("codex_cli_rs/0.5.2"));
    }

    #[test]
    fn test_is_not_official_client() {
        assert!(!CodexAdapter::is_official_client("Mozilla/5.0"));
        assert!(!CodexAdapter::is_official_client("curl/7.68.0"));
        assert!(!CodexAdapter::is_official_client("python-requests/2.25.1"));
        assert!(!CodexAdapter::is_official_client("codex_other/1.0.0"));
        assert!(!CodexAdapter::is_official_client(""));
    }

    #[test]
    fn test_is_official_client_partial_match() {
        // 必须从开头匹配
        assert!(!CodexAdapter::is_official_client("some codex_vscode/1.0.0"));
        assert!(!CodexAdapter::is_official_client(
            "prefix_codex_cli_rs/1.0.0"
        ));
    }

    #[test]
    fn test_codex_provider_uses_chat_completions_from_active_wire_api() {
        let provider = create_provider(json!({
            "config": r#"
model_provider = "chat_only"
model = "gpt-5"

[model_providers.chat_only]
name = "Chat Only"
base_url = "https://example.com/v1"
wire_api = "chat"
"#
        }));

        assert!(codex_provider_uses_chat_completions(&provider));
        assert!(should_convert_codex_responses_to_chat(
            &provider,
            "/responses?stream=true"
        ));
        assert!(!should_convert_codex_responses_to_chat(
            &provider,
            "/chat/completions"
        ));
    }

    #[test]
    fn test_codex_provider_uses_chat_completions_from_full_chat_url() {
        let provider = create_provider(json!({
            "base_url": "https://example.com/v1/chat/completions"
        }));

        assert!(codex_provider_uses_chat_completions(&provider));
        assert!(should_convert_codex_responses_to_chat(
            &provider,
            "/v1/responses/compact"
        ));
    }

    #[test]
    fn test_codex_provider_uses_chat_completions_from_meta_api_format_for_compact() {
        let mut provider = create_provider(json!({
            "base_url": "https://example.com/v1"
        }));
        provider.meta = Some(crate::provider::ProviderMeta {
            api_format: Some("openai_chat".to_string()),
            ..Default::default()
        });

        assert!(codex_provider_uses_chat_completions(&provider));
        assert!(should_convert_codex_responses_to_chat(
            &provider,
            "/responses/compact?stream=true"
        ));
    }

    #[test]
    fn test_codex_provider_uses_chat_completions_from_meta_api_format_for_responses() {
        let mut provider = create_provider(json!({
            "base_url": "https://api.deepseek.com/v1"
        }));
        provider.meta = Some(crate::provider::ProviderMeta {
            api_format: Some("openai_chat".to_string()),
            ..Default::default()
        });

        assert!(should_convert_codex_responses_to_chat(
            &provider,
            "/v1/responses"
        ));
    }

    #[test]
    fn test_apply_codex_chat_upstream_model_uses_provider_config_model() {
        let mut provider = create_provider(json!({
            "config": r#"
model_provider = "deepseek"
model = "deepseek-v4-flash"

[model_providers.deepseek]
name = "DeepSeek"
base_url = "https://api.deepseek.com/v1"
wire_api = "responses"
"#
        }));
        provider.meta = Some(crate::provider::ProviderMeta {
            api_format: Some("openai_chat".to_string()),
            ..Default::default()
        });
        let mut body = json!({
            "model": CODEX_CHAT_CLIENT_MODEL,
            "input": "ping"
        });

        let upstream_model = apply_codex_chat_upstream_model(&provider, &mut body);

        assert_eq!(upstream_model.as_deref(), Some("deepseek-v4-flash"));
        assert_eq!(
            body.get("model").and_then(|v| v.as_str()),
            Some("deepseek-v4-flash")
        );
    }
}