//! 客户端适配器注册表与结构化结果（agent-client-parity P8b）。
//!
//! 每个 agent 客户端（Claude Code、Codex、DSH）声明三件事：本机是否装有（detect）、本项目当前状态的
//! 只读判定（static_status）、收敛到期望状态（apply）。接入编排与 verify 只经注册表遍历，
//! 不按客户端写分支；新增客户端 = 新增一个适配器并登记到 `registry()`。

use serde::{Deserialize, Serialize};
use std::path::Path;

#[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize)]
#[serde(rename_all = "snake_case")]
pub enum ClientId {
    Claude,
    Codex,
    Dsh,
}

#[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize)]
#[serde(rename_all = "snake_case")]
pub enum NotApplicableReason {
    /// 控制面项目（mcp_scope=global）：不写项目级条目，回退全局地址
    ControlPlane,
    /// WSL 路径项目（2026-07-04 裁决放弃）：Claude local 与 DSH 不支持
    Wsl,
}

/// 单个客户端在一次接入或静态检查中的结果（命名与设计文档 §4 的步骤状态一致）。
/// - 成功态：converged（已一致、未写）、applied（新写入）、refreshed（替换了旧托管条目）、removed（按期望移除）；
/// - 按边界不改动：manual_kept（手写同名配置）、other_project（共享项目键属于他项目）；
/// - 不计失败：not_installed、not_applicable（控制面 / WSL）、deferred（批量操作末尾统一刷新）；
/// - 未就绪：missing（静态检查：已安装但本项目未配置或已过期）、unavailable（无法确认现状）、
///   needs_human（需人工清理）、failed（尝试写入但失败）。
#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
#[serde(tag = "state", rename_all = "snake_case")]
pub enum ClientOutcome {
    Converged,
    Applied,
    Refreshed,
    Removed,
    ManualKept,
    OtherProject { owner: String },
    NotInstalled,
    NotApplicable { reason: NotApplicableReason },
    Deferred,
    Missing,
    Unavailable { reason: String },
    NeedsHuman { reason: String },
    Failed { reason: String },
}

impl ClientOutcome {
    /// 该端对本项目已处于期望状态（含按边界保留手写配置、未安装、不适用）——不计为失败。
    pub fn is_settled(&self) -> bool {
        matches!(
            self,
            Self::Converged
                | Self::Applied
                | Self::Refreshed
                | Self::Removed
                | Self::ManualKept
                | Self::NotInstalled
                | Self::NotApplicable { .. }
                | Self::Deferred
        )
    }

    /// 给人和 agent 读的一行中文说明。
    pub fn describe(&self) -> String {
        match self {
            Self::Converged => "已一致（未改动）".into(),
            Self::Applied => "已写入".into(),
            Self::Refreshed => "已刷新".into(),
            Self::Removed => "已移除".into(),
            Self::ManualKept => "保留手写配置，炼境未覆盖".into(),
            Self::OtherProject { owner } => {
                format!("生效条目属于项目 {owner}（共享项目键），炼境未改动")
            }
            Self::NotInstalled => "未安装".into(),
            Self::NotApplicable { reason } => match reason {
                NotApplicableReason::ControlPlane => "不适用（控制面项目走全局地址）".into(),
                NotApplicableReason::Wsl => "不支持（WSL 路径项目）".into(),
            },
            Self::Deferred => "本次跳过（批量操作末尾统一刷新）".into(),
            Self::Missing => "未配置或已过期".into(),
            Self::Unavailable { reason } => format!("无法确认：{reason}"),
            Self::NeedsHuman { reason } => format!("需人工处理：{reason}"),
            Self::Failed { reason } => format!("失败：{reason}"),
        }
    }
}

#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
pub struct ClientReport {
    pub client: ClientId,
    #[serde(flatten)]
    pub outcome: ClientOutcome,
}

impl ClientReport {
    pub fn new(client: ClientId, outcome: ClientOutcome) -> Self {
        Self { client, outcome }
    }
}

/// 项目在本机的事实，由调用方从登记与磁盘读取后注入。
pub struct ProjectFacts<'a> {
    pub project_id: &'a str,
    pub root: &'a Path,
    /// 根目录 context.json 声明 mcp_scope=global
    pub control_plane: bool,
    /// 根目录是 WSL UNC 路径
    pub wsl: bool,
}

/// 本次接入的期望连接参数（项目专用地址 + 稳定 helper 命令）。
pub struct DesiredMcp {
    pub port: u16,
    pub server_url: String,
    pub header_helper: String,
    /// false 时 DSH 不逐项目刷新（批量重注入末尾统一刷新）
    pub refresh_dsh: bool,
}

pub trait ClientAdapter: Sync {
    fn id(&self) -> ClientId;
    /// 本机是否装有该客户端（只读、毫秒级，不起子进程）。
    fn detect(&self) -> bool;
    /// 只读判定本项目在该端的配置状态，不写任何文件、不起子进程。
    fn static_status(&self, project: &ProjectFacts, desired: &DesiredMcp) -> ClientOutcome;
    /// 收敛到期望状态；调用方须持有接入锁。失败返回 failed / unavailable，不 panic、不中断其他端。
    fn apply(&self, project: &ProjectFacts, desired: &DesiredMcp) -> ClientOutcome;
}

/// 三端适配器注册表；顺序即报告顺序。
/// 绞杀者过渡：三个适配器暂实现在 mcp_inject（依赖其私有辅助函数，后者仍直接取连接池），本模块因此
/// 传递依赖投影层——适应度测试只拦本模块源码。P8d 起把适配器逐个迁入 onboard，届时改为纯注入。
pub fn registry() -> [&'static dyn ClientAdapter; 3] {
    [
        &crate::mcp_inject::CLAUDE_ADAPTER,
        &crate::mcp_inject::CODEX_ADAPTER,
        &crate::mcp_inject::DSH_ADAPTER,
    ]
}

/// 根目录是否为 WSL UNC 路径（\\wsl.localhost\… 或 \\wsl$\…）。
pub fn is_wsl_root(root: &Path) -> bool {
    let text = root.display().to_string().to_ascii_lowercase();
    text.starts_with(r"\\wsl.localhost\") || text.starts_with(r"\\wsl$\")
}

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

    #[test]
    fn registry_lists_exactly_three_clients_in_order() {
        let ids: Vec<ClientId> = registry().iter().map(|adapter| adapter.id()).collect();
        assert_eq!(ids, vec![ClientId::Claude, ClientId::Codex, ClientId::Dsh]);
    }

    #[test]
    fn settled_states_exclude_failures_and_missing() {
        let settled = [
            ClientOutcome::Converged,
            ClientOutcome::Applied,
            ClientOutcome::Refreshed,
            ClientOutcome::Removed,
            ClientOutcome::ManualKept,
            ClientOutcome::NotInstalled,
            ClientOutcome::NotApplicable {
                reason: NotApplicableReason::ControlPlane,
            },
            ClientOutcome::Deferred,
        ];
        assert!(settled.iter().all(ClientOutcome::is_settled));
        let unsettled = [
            ClientOutcome::Missing,
            ClientOutcome::OtherProject { owner: "x".into() },
            ClientOutcome::Unavailable { reason: "r".into() },
            ClientOutcome::NeedsHuman { reason: "r".into() },
            ClientOutcome::Failed { reason: "r".into() },
        ];
        assert!(!unsettled.iter().any(ClientOutcome::is_settled));
    }

    #[test]
    fn report_serializes_flat_with_snake_case_state() {
        let report = ClientReport::new(
            ClientId::Dsh,
            ClientOutcome::NotApplicable {
                reason: NotApplicableReason::ControlPlane,
            },
        );
        assert_eq!(
            serde_json::to_value(&report).unwrap(),
            serde_json::json!({"client": "dsh", "state": "not_applicable", "reason": "control_plane"})
        );
        assert_eq!(
            serde_json::to_value(ClientReport::new(ClientId::Dsh, ClientOutcome::Deferred))
                .unwrap(),
            serde_json::json!({"client": "dsh", "state": "deferred"})
        );
        let failed = ClientReport::new(
            ClientId::Claude,
            ClientOutcome::Unavailable {
                reason: "claude CLI 未找到".into(),
            },
        );
        assert_eq!(
            serde_json::to_value(&failed).unwrap()["state"],
            "unavailable"
        );
    }

    #[test]
    fn wsl_roots_detected_case_insensitively() {
        assert!(is_wsl_root(Path::new(r"\\wsl.localhost\Ubuntu\home\a")));
        assert!(is_wsl_root(Path::new(r"\\WSL$\Ubuntu\home\a")));
        assert!(!is_wsl_root(Path::new(r"E:\code-project\a")));
    }
}