//! Copilot 请求优化器
//!
//! 解决 GitHub Copilot 代理消耗量异常问题（Issue #1813）。
//!
//! Copilot 使用 `x-initiator` 请求头区分「用户发起」和「agent 续写」：
//! - `user`：计为一次 premium interaction（扣额度）
//! - `agent`：视为上一次交互的延续（不额外扣费）
//!
//! 参考实现: https://github.com/caozhiyuan/copilot-api

use serde_json::Value;
use sha2::{Digest, Sha256};
use uuid::Uuid;

/// 请求分类结果
#[derive(Debug, Clone)]
pub struct CopilotClassification {
    /// "user" 或 "agent" — 映射到 x-initiator 请求头
    pub initiator: &'static str,
    /// 是否为 warmup/探针请求（可降级到小模型）
    pub is_warmup: bool,
    /// 是否为上下文压缩请求
    pub is_compact: bool,
}

/// 分类 Anthropic 格式的请求体，决定 Copilot 请求头。
///
/// 分类算法（只检查最后一条消息，与参考实现 caozhiyuan/copilot-api 对齐）：
/// 1. 无消息 → "user"（安全默认，首次请求）
/// 2. 最后消息 role=user：
///    - content 中存在非 tool_result 类型 block → "user"
///    - content 全部是 tool_result → "agent"
///    - 匹配 compact 模式 → "agent"
/// 3. 最后消息 role 非 user → "user"（安全默认）
///
/// Warmup 检测（与参考实现对齐）：
/// - 请求头中有 `anthropic-beta` + 无 tools + 非 compact → warmup
///
/// `compact_detection`：是否启用 compact 检测。为 false 时跳过，
/// 确保 `CopilotOptimizerConfig.compact_detection` 开关真正生效。
pub fn classify_request(
    body: &Value,
    has_anthropic_beta: bool,
    compact_detection: bool,
) -> CopilotClassification {
    let is_compact = compact_detection && is_compact_request(body);

    let messages = match body.get("messages").and_then(|m| m.as_array()) {
        Some(msgs) if !msgs.is_empty() => msgs,
        _ => {
            return CopilotClassification {
                initiator: "user",
                is_warmup: is_warmup_request(body, has_anthropic_beta, false),
                is_compact: false,
            }
        }
    };

    let last_msg = &messages[messages.len() - 1];
    let role = last_msg.get("role").and_then(|r| r.as_str()).unwrap_or("");

    // 只有 role=user 的消息需要细分
    if role != "user" {
        return CopilotClassification {
            initiator: "user",
            is_warmup: false,
            is_compact,
        };
    }

    // 参考实现的判定逻辑（Messages API 路径）：
    // 如果 content 是数组，检查是否有非 tool_result 的 block
    // 有 → "user"，全是 tool_result → "agent"
    // 如果 content 是字符串 → "user"
    let is_user_initiated = match last_msg.get("content") {
        Some(content) if content.is_array() => {
            let blocks = content.as_array().unwrap();
            // 存在非 tool_result block → 用户发起
            blocks
                .iter()
                .any(|block| block.get("type").and_then(|t| t.as_str()) != Some("tool_result"))
        }
        Some(content) if content.is_string() => true,
        _ => false,
    };

    let initiator = if !is_user_initiated || is_compact {
        "agent"
    } else {
        "user"
    };

    CopilotClassification {
        initiator,
        is_warmup: initiator == "user" && is_warmup_request(body, has_anthropic_beta, is_compact),
        is_compact,
    }
}

/// 检测是否为 warmup/探针请求（适合降级到小模型）。
///
/// 与参考实现对齐，三个条件同时满足：
/// 1. 请求头有 `anthropic-beta`（Claude Code warmup 探针的标志）
/// 2. 无 tools 定义
/// 3. 非 compact 请求
fn is_warmup_request(body: &Value, has_anthropic_beta: bool, is_compact: bool) -> bool {
    if !has_anthropic_beta || is_compact {
        return false;
    }
    // 无工具定义
    !matches!(body.get("tools"), Some(tools) if tools.is_array() && !tools.as_array().unwrap().is_empty())
}

/// 检测是否为 Claude Code 上下文压缩/compact 请求。
///
/// 只匹配 Claude Code **内部生成**的机器特征，不匹配用户可能手动输入的通用短语，
/// 避免将真实用户请求误标为 agent。
///
/// 强特征来源：
/// 1. system prompt — Claude Code compact 模式会设置专用 system prompt，用户无法手动设置
/// 2. "CRITICAL: Respond with TEXT ONLY. Do NOT call any tools." — 机器指令
/// 3. 同时包含 "Pending Tasks:" 和 "Current Work:" — Claude Code compact 的结构标记
fn is_compact_request(body: &Value) -> bool {
    // 信号 1: system prompt 以 Claude Code compact 专用前缀开头
    // 用户在 Claude Code 中无法直接控制 system prompt，这是最可靠的信号
    if let Some(system) = body.get("system") {
        let system_text = if let Some(s) = system.as_str() {
            s.to_string()
        } else if let Some(arr) = system.as_array() {
            arr.iter()
                .filter_map(|b| b.get("text").and_then(|t| t.as_str()))
                .collect::<Vec<_>>()
                .join(" ")
        } else {
            String::new()
        };

        if system_text
            .starts_with("You are a helpful AI assistant tasked with summarizing conversations")
        {
            return true;
        }
    }

    // 信号 2 & 3: 检查最后一条用户消息中的机器生成特征
    let messages = match body.get("messages").and_then(|m| m.as_array()) {
        Some(msgs) => msgs,
        None => return false,
    };

    if let Some(last_msg) = messages.last() {
        if last_msg.get("role").and_then(|r| r.as_str()) != Some("user") {
            return false;
        }

        let text = extract_text_from_message(last_msg);

        // 信号 2: Claude Code compact 的机器指令（大小写敏感，精确匹配）
        if text.contains("CRITICAL: Respond with TEXT ONLY. Do NOT call any tools.") {
            return true;
        }

        // 信号 3: Claude Code compact 的结构标记（两个同时出现才算）
        if text.contains("Pending Tasks:") && text.contains("Current Work:") {
            return true;
        }
    }

    false
}

/// 合并用户消息中的 tool_result 和 text block。
///
/// 与参考实现 `mergeToolResultForClaude` 对齐：
///
/// **消息内部合并**（核心）：在单条 user 消息内，将 text block 吸收进 tool_result block，
/// 使整条消息只剩 tool_result 类型 block。这样 Copilot 不会将其视为用户发起的交互。
///
/// 场景：Claude Code 在 skill 调用、edit hook、plan 提醒等场景下，会发送混合了
/// tool_result + text 的用户消息。text block 的存在让 Copilot 将其计为 premium request。
///
/// **跨消息合并**（补充）：连续的 tool_result-only 用户消息合并为一条。
pub fn merge_tool_results(mut body: Value) -> Value {
    let messages = match body.get_mut("messages").and_then(|m| m.as_array_mut()) {
        Some(msgs) if !msgs.is_empty() => msgs,
        _ => return body,
    };

    // Phase 1: 消息内部合并 — 将 text block 吸收进 tool_result block
    for msg in messages.iter_mut() {
        if msg.get("role").and_then(|r| r.as_str()) != Some("user") {
            continue;
        }
        let content = match msg.get("content").and_then(|c| c.as_array()) {
            Some(blocks) => blocks,
            None => continue,
        };

        // 分离 tool_result 和 text block
        let mut tool_results: Vec<Value> = Vec::new();
        let mut text_blocks: Vec<Value> = Vec::new();
        let mut valid = true;

        for block in content {
            match block.get("type").and_then(|t| t.as_str()) {
                Some("tool_result") => tool_results.push(block.clone()),
                Some("text") => text_blocks.push(block.clone()),
                _ => {
                    // 存在其他类型 block → 跳过此消息
                    valid = false;
                    break;
                }
            }
        }

        // 必须同时有 tool_result 和 text 才需要合并
        if !valid || tool_results.is_empty() || text_blocks.is_empty() {
            continue;
        }

        // 合并策略（与参考实现对齐）
        let merged = merge_blocks_into_tool_results(tool_results, text_blocks);
        msg["content"] = Value::Array(merged);
    }

    // Phase 2: 跨消息合并 — 连续的 tool_result-only 用户消息合并
    let messages = body["messages"].as_array().unwrap().clone();
    if messages.len() <= 1 {
        return body;
    }

    let mut merged_msgs: Vec<Value> = Vec::with_capacity(messages.len());
    let mut i = 0;

    while i < messages.len() {
        if is_tool_result_only_message(&messages[i]) {
            let mut combined_content: Vec<Value> = Vec::new();
            while i < messages.len() && is_tool_result_only_message(&messages[i]) {
                if let Some(content) = messages[i].get("content").and_then(|c| c.as_array()) {
                    combined_content.extend(content.iter().cloned());
                }
                i += 1;
            }
            if !combined_content.is_empty() {
                merged_msgs.push(serde_json::json!({
                    "role": "user",
                    "content": combined_content
                }));
            }
        } else {
            merged_msgs.push(messages[i].clone());
            i += 1;
        }
    }

    body["messages"] = Value::Array(merged_msgs);
    body
}

/// 基于最后一条用户消息内容生成确定性 Request ID。
///
/// 与参考实现对齐：
/// - 哈希输入: sessionId + lastUserContent（排除 tool_result 和 cache_control）
/// - 找不到用户内容时退化为随机 UUID
/// - 使用 UUID v4 格式
pub fn deterministic_request_id(body: &Value, session_id: &str) -> String {
    let last_user_content = find_last_user_content(body);

    match last_user_content {
        Some(content) => {
            let mut hasher = Sha256::new();
            hasher.update(session_id.as_bytes());
            hasher.update(content.as_bytes());
            let result = hasher.finalize();

            let mut bytes = [0u8; 16];
            bytes.copy_from_slice(&result[..16]);
            // UUID v4 版本位和变体位（与参考实现一致）
            bytes[6] = (bytes[6] & 0x0f) | 0x40; // version 4
            bytes[8] = (bytes[8] & 0x3f) | 0x80; // variant 1

            Uuid::from_bytes(bytes).to_string()
        }
        None => Uuid::new_v4().to_string(),
    }
}

// ─── 内部辅助 ─────────────────────────────────

/// 查找最后一条 user 消息的非 tool_result 文本内容。
///
/// 与参考实现的 `findLastUserContent` 对齐：
/// - 从后往前遍历消息
/// - 排除 tool_result block
/// - 排除 cache_control 字段
fn find_last_user_content(body: &Value) -> Option<String> {
    let messages = body.get("messages").and_then(|m| m.as_array())?;

    for msg in messages.iter().rev() {
        if msg.get("role").and_then(|r| r.as_str()) != Some("user") {
            continue;
        }
        let content = msg.get("content")?;

        if let Some(s) = content.as_str() {
            return Some(s.to_string());
        }

        if let Some(blocks) = content.as_array() {
            // 过滤 tool_result，保留其他 block（去掉 cache_control）
            let filtered: Vec<Value> = blocks
                .iter()
                .filter(|b| b.get("type").and_then(|t| t.as_str()) != Some("tool_result"))
                .map(|b| {
                    let mut b = b.clone();
                    if let Some(obj) = b.as_object_mut() {
                        obj.remove("cache_control");
                    }
                    b
                })
                .collect();

            if !filtered.is_empty() {
                return Some(serde_json::to_string(&filtered).unwrap_or_default());
            }
        }
    }

    None
}

/// 将 text block 合并进 tool_result block。
///
/// 两种合并策略（与参考实现对齐）：
/// - 数量相等：一一对应，text 追加到对应 tool_result 的 content 中
/// - 数量不等：所有 text 追加到最后一个 tool_result 的 content 中
fn merge_blocks_into_tool_results(
    mut tool_results: Vec<Value>,
    text_blocks: Vec<Value>,
) -> Vec<Value> {
    if tool_results.len() == text_blocks.len() {
        // 一一对应合并
        for (tr, tb) in tool_results.iter_mut().zip(text_blocks.iter()) {
            append_text_to_tool_result(tr, tb);
        }
    } else {
        // 所有 text 追加到最后一个 tool_result
        if let Some(last_tr) = tool_results.last_mut() {
            for tb in &text_blocks {
                append_text_to_tool_result(last_tr, tb);
            }
        }
    }
    tool_results
}

/// 将 text block 的内容追加到 tool_result 的 content 中
fn append_text_to_tool_result(tool_result: &mut Value, text_block: &Value) {
    let text = text_block
        .get("text")
        .and_then(|t| t.as_str())
        .unwrap_or("");
    if text.trim().is_empty() {
        return;
    }

    // tool_result 的 content 可以是字符串或数组
    match tool_result.get("content") {
        Some(c) if c.is_string() => {
            let existing = c.as_str().unwrap_or("");
            tool_result["content"] = Value::String(format!("{existing}\n{text}"));
        }
        Some(c) if c.is_array() => {
            let arr = tool_result["content"].as_array_mut().unwrap();
            arr.push(serde_json::json!({"type": "text", "text": text}));
        }
        _ => {
            // content 缺失或 null — 直接设置
            tool_result["content"] = Value::String(text.to_string());
        }
    }
}

/// 从消息中提取文本内容
fn extract_text_from_message(msg: &Value) -> String {
    match msg.get("content") {
        Some(content) if content.is_string() => content.as_str().unwrap_or("").to_string(),
        Some(content) if content.is_array() => {
            let blocks = content.as_array().unwrap();
            blocks
                .iter()
                .filter_map(|block| {
                    if block.get("type").and_then(|t| t.as_str()) == Some("text") {
                        block.get("text").and_then(|t| t.as_str())
                    } else {
                        None
                    }
                })
                .collect::<Vec<_>>()
                .join(" ")
        }
        _ => String::new(),
    }
}

/// 判断消息是否为 tool_result-only 的用户消息
fn is_tool_result_only_message(msg: &Value) -> bool {
    if msg.get("role").and_then(|r| r.as_str()) != Some("user") {
        return false;
    }
    match msg.get("content").and_then(|c| c.as_array()) {
        Some(blocks) if !blocks.is_empty() => blocks
            .iter()
            .all(|block| block.get("type").and_then(|t| t.as_str()) == Some("tool_result")),
        _ => false,
    }
}

// ─── 测试 ─────────────────────────────────────

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

    // === classify_request 测试 ===

    #[test]
    fn test_classify_user_text_message() {
        let body = json!({
            "model": "claude-sonnet-4-20250514",
            "messages": [
                {"role": "user", "content": "Hello, please help me write some code"}
            ]
        });
        let result = classify_request(&body, false, true);
        assert_eq!(result.initiator, "user");
        assert!(!result.is_compact);
    }

    #[test]
    fn test_classify_user_text_array_message() {
        let body = json!({
            "model": "claude-sonnet-4-20250514",
            "messages": [
                {"role": "user", "content": [
                    {"type": "text", "text": "Please explain this code"}
                ]}
            ]
        });
        let result = classify_request(&body, false, true);
        assert_eq!(result.initiator, "user");
    }

    #[test]
    fn test_classify_tool_result_only() {
        let body = json!({
            "model": "claude-sonnet-4-20250514",
            "tools": [{"name": "Read", "description": "Read a file", "input_schema": {}}],
            "messages": [
                {"role": "user", "content": "Read the file"},
                {"role": "assistant", "content": [
                    {"type": "text", "text": "I'll read that file."},
                    {"type": "tool_use", "id": "toolu_123", "name": "Read", "input": {"path": "/tmp/test.rs"}}
                ]},
                {"role": "user", "content": [
                    {"type": "tool_result", "tool_use_id": "toolu_123", "content": "file contents here"}
                ]}
            ]
        });
        let result = classify_request(&body, true, true);
        assert_eq!(result.initiator, "agent");
        assert!(!result.is_warmup);
    }

    #[test]
    fn test_classify_tool_result_with_text_block() {
        // 参考实现的关键场景：tool_result + text block
        // 有非 tool_result block → 仍然是 "user"
        let body = json!({
            "model": "claude-sonnet-4-20250514",
            "messages": [
                {"role": "user", "content": [
                    {"type": "tool_result", "tool_use_id": "toolu_123", "content": "file contents"},
                    {"type": "text", "text": "Now please refactor this code"}
                ]}
            ]
        });
        let result = classify_request(&body, false, true);
        assert_eq!(result.initiator, "user");
    }

    #[test]
    fn test_classify_empty_messages() {
        let body = json!({
            "model": "claude-sonnet-4-20250514",
            "messages": []
        });
        let result = classify_request(&body, false, true);
        assert_eq!(result.initiator, "user");
    }

    #[test]
    fn test_classify_no_messages() {
        let body = json!({"model": "claude-sonnet-4-20250514"});
        let result = classify_request(&body, false, true);
        assert_eq!(result.initiator, "user");
    }

    #[test]
    fn test_classify_compact_request_system_prompt() {
        // compact 通过 system prompt 强特征检测
        let body = json!({
            "model": "claude-sonnet-4-20250514",
            "system": "You are a helpful AI assistant tasked with summarizing conversations. Please create a summary.",
            "messages": [
                {"role": "user", "content": "Here is the conversation history to summarize..."}
            ]
        });
        let result = classify_request(&body, false, true);
        assert_eq!(result.initiator, "agent");
        assert!(result.is_compact);
    }

    #[test]
    fn test_classify_compact_request_critical_marker() {
        // compact 通过 CRITICAL 机器指令检测
        let body = json!({
            "model": "claude-sonnet-4-20250514",
            "messages": [
                {"role": "user", "content": [
                    {"type": "text", "text": "CRITICAL: Respond with TEXT ONLY. Do NOT call any tools. Summarize the conversation."}
                ]}
            ]
        });
        let result = classify_request(&body, false, true);
        assert_eq!(result.initiator, "agent");
        assert!(result.is_compact);
    }

    #[test]
    fn test_classify_compact_disabled_by_config() {
        // compact_detection=false 时，即使内容匹配也不标记为 compact
        let body = json!({
            "model": "claude-sonnet-4-20250514",
            "system": "You are a helpful AI assistant tasked with summarizing conversations.",
            "messages": [
                {"role": "user", "content": "Summarize"}
            ]
        });
        let result = classify_request(&body, false, false); // compact_detection=false
        assert_eq!(result.initiator, "user"); // 不被标记为 agent
        assert!(!result.is_compact);
    }

    #[test]
    fn test_no_false_positive_on_user_summarize_request() {
        // P1 修复验证：用户手动输入 "summarize the conversation" 不应被误判为 compact
        let body = json!({
            "model": "claude-sonnet-4-20250514",
            "messages": [
                {"role": "user", "content": "Please summarize the conversation so far into a concise summary."}
            ]
        });
        let result = classify_request(&body, false, true);
        // 没有 system prompt 强特征，也没有 CRITICAL 指令 → 不是 compact → user
        assert_eq!(result.initiator, "user");
        assert!(!result.is_compact);
    }

    // === warmup 测试（与参考实现对齐） ===

    #[test]
    fn test_warmup_with_anthropic_beta_no_tools() {
        let body = json!({
            "model": "claude-sonnet-4-20250514",
            "messages": [
                {"role": "user", "content": "Hello"}
            ]
        });
        // has_anthropic_beta=true, 无 tools → warmup
        let result = classify_request(&body, true, true);
        assert!(result.is_warmup);
    }

    #[test]
    fn test_not_warmup_without_anthropic_beta() {
        let body = json!({
            "model": "claude-sonnet-4-20250514",
            "messages": [
                {"role": "user", "content": "Hello"}
            ]
        });
        // has_anthropic_beta=false → 不是 warmup
        let result = classify_request(&body, false, true);
        assert!(!result.is_warmup);
    }

    #[test]
    fn test_not_warmup_with_tools() {
        let body = json!({
            "model": "claude-sonnet-4-20250514",
            "tools": [{"name": "Read", "description": "Read a file", "input_schema": {}}],
            "messages": [
                {"role": "user", "content": "Hello"}
            ]
        });
        // 有 tools → 不是 warmup（即使有 anthropic-beta）
        let result = classify_request(&body, true, true);
        assert!(!result.is_warmup);
    }

    #[test]
    fn test_not_warmup_when_agent() {
        // tool_result → agent → 不判定 warmup
        let body = json!({
            "model": "claude-sonnet-4-20250514",
            "messages": [
                {"role": "user", "content": [
                    {"type": "tool_result", "tool_use_id": "toolu_123", "content": "ok"}
                ]}
            ]
        });
        let result = classify_request(&body, true, true);
        assert_eq!(result.initiator, "agent");
        assert!(!result.is_warmup);
    }

    // === merge_tool_results 测试 ===

    #[test]
    fn test_merge_intra_message_tool_result_text() {
        // 核心场景：消息内部 tool_result + text → text 被吸收进 tool_result
        let body = json!({
            "messages": [
                {"role": "user", "content": [
                    {"type": "tool_result", "tool_use_id": "t1", "content": "file contents"},
                    {"type": "text", "text": "skill output here"}
                ]}
            ]
        });
        let result = merge_tool_results(body);
        let content = result["messages"][0]["content"].as_array().unwrap();
        // 应只剩 1 个 tool_result block（text 被吸收）
        assert_eq!(content.len(), 1);
        assert_eq!(content[0]["type"], "tool_result");
        // tool_result 的 content 应包含原始内容 + 吸收的 text
        let tr_content = content[0]["content"].as_str().unwrap();
        assert!(tr_content.contains("file contents"));
        assert!(tr_content.contains("skill output here"));
    }

    #[test]
    fn test_merge_intra_message_equal_count() {
        // 数量相等：一一对应合并
        let body = json!({
            "messages": [
                {"role": "user", "content": [
                    {"type": "tool_result", "tool_use_id": "t1", "content": "result1"},
                    {"type": "text", "text": "text1"},
                    {"type": "tool_result", "tool_use_id": "t2", "content": "result2"},
                    {"type": "text", "text": "text2"}
                ]}
            ]
        });
        let result = merge_tool_results(body);
        let content = result["messages"][0]["content"].as_array().unwrap();
        assert_eq!(content.len(), 2);
        assert!(content[0]["content"].as_str().unwrap().contains("text1"));
        assert!(content[1]["content"].as_str().unwrap().contains("text2"));
    }

    #[test]
    fn test_merge_intra_message_empty_text_ignored() {
        // 空 text block 不追加内容
        let body = json!({
            "messages": [
                {"role": "user", "content": [
                    {"type": "tool_result", "tool_use_id": "t1", "content": "result"},
                    {"type": "text", "text": ""}
                ]}
            ]
        });
        let result = merge_tool_results(body);
        let content = result["messages"][0]["content"].as_array().unwrap();
        assert_eq!(content.len(), 1);
        // 空 text 不改变原始 content
        assert_eq!(content[0]["content"], "result");
    }

    #[test]
    fn test_merge_intra_skips_other_block_types() {
        // 有非 tool_result/text 的 block → 跳过整条消息
        let body = json!({
            "messages": [
                {"role": "user", "content": [
                    {"type": "tool_result", "tool_use_id": "t1", "content": "result"},
                    {"type": "image", "source": {"data": "..."}},
                    {"type": "text", "text": "caption"}
                ]}
            ]
        });
        let result = merge_tool_results(body);
        let content = result["messages"][0]["content"].as_array().unwrap();
        // 未合并，保持原样 3 个 block
        assert_eq!(content.len(), 3);
    }

    #[test]
    fn test_merge_cross_message_consecutive() {
        // 跨消息合并：连续 tool_result-only 用户消息
        let body = json!({
            "messages": [
                {"role": "user", "content": "Read files"},
                {"role": "assistant", "content": [
                    {"type": "tool_use", "id": "t1", "name": "Read", "input": {}},
                    {"type": "tool_use", "id": "t2", "name": "Read", "input": {}}
                ]},
                {"role": "user", "content": [
                    {"type": "tool_result", "tool_use_id": "t1", "content": "file1"}
                ]},
                {"role": "user", "content": [
                    {"type": "tool_result", "tool_use_id": "t2", "content": "file2"}
                ]}
            ]
        });
        let result = merge_tool_results(body);
        let messages = result["messages"].as_array().unwrap();
        assert_eq!(messages.len(), 3);
        let merged_content = messages[2]["content"].as_array().unwrap();
        assert_eq!(merged_content.len(), 2);
    }

    #[test]
    fn test_merge_does_not_affect_normal_messages() {
        let body = json!({
            "messages": [
                {"role": "user", "content": "Hello"},
                {"role": "assistant", "content": "Hi!"},
                {"role": "user", "content": "How are you?"}
            ]
        });
        let result = merge_tool_results(body.clone());
        assert_eq!(result["messages"], body["messages"]);
    }

    // === deterministic_request_id 测试 ===

    #[test]
    fn test_deterministic_id_stable() {
        let body = json!({
            "model": "claude-sonnet-4-20250514",
            "messages": [{"role": "user", "content": "Hello"}]
        });
        let id1 = deterministic_request_id(&body, "session1");
        let id2 = deterministic_request_id(&body, "session1");
        assert_eq!(id1, id2);
    }

    #[test]
    fn test_deterministic_id_varies_by_content() {
        let body1 = json!({
            "messages": [{"role": "user", "content": "Hello"}]
        });
        let body2 = json!({
            "messages": [{"role": "user", "content": "Goodbye"}]
        });
        let id1 = deterministic_request_id(&body1, "session1");
        let id2 = deterministic_request_id(&body2, "session1");
        assert_ne!(id1, id2);
    }

    #[test]
    fn test_deterministic_id_varies_by_session() {
        let body = json!({
            "messages": [{"role": "user", "content": "Hello"}]
        });
        let id1 = deterministic_request_id(&body, "session1");
        let id2 = deterministic_request_id(&body, "session2");
        assert_ne!(id1, id2);
    }

    #[test]
    fn test_deterministic_id_ignores_tool_result() {
        // tool_result 内容不同，但 user text 相同 → 相同 ID
        let body1 = json!({
            "messages": [
                {"role": "user", "content": "Hello"},
                {"role": "assistant", "content": "Hi"},
                {"role": "user", "content": [
                    {"type": "tool_result", "tool_use_id": "t1", "content": "version_A"}
                ]},
                {"role": "user", "content": "do something"}
            ]
        });
        let body2 = json!({
            "messages": [
                {"role": "user", "content": "Hello"},
                {"role": "assistant", "content": "Hi"},
                {"role": "user", "content": [
                    {"type": "tool_result", "tool_use_id": "t1", "content": "version_B"}
                ]},
                {"role": "user", "content": "do something"}
            ]
        });
        let id1 = deterministic_request_id(&body1, "s");
        let id2 = deterministic_request_id(&body2, "s");
        assert_eq!(id1, id2);
    }

    #[test]
    fn test_deterministic_id_fallback_when_no_user_content() {
        // 无用户消息 → 退化为随机 UUID（每次不同）
        let body = json!({
            "messages": [
                {"role": "assistant", "content": "Hi"}
            ]
        });
        let id1 = deterministic_request_id(&body, "s");
        let id2 = deterministic_request_id(&body, "s");
        // 随机 UUID，每次应不同
        assert_ne!(id1, id2);
    }

    #[test]
    fn test_deterministic_id_is_valid_uuid() {
        let body = json!({
            "messages": [{"role": "user", "content": "test"}]
        });
        let id = deterministic_request_id(&body, "session");
        assert!(Uuid::parse_str(&id).is_ok());
    }

    // === compact 检测增强测试 ===

    #[test]
    fn test_compact_detection_system_prompt() {
        let body = json!({
            "system": "You are a helpful AI assistant tasked with summarizing conversations. Please provide a concise summary.",
            "messages": [
                {"role": "user", "content": "Here is the conversation to summarize..."}
            ]
        });
        assert!(is_compact_request(&body));
    }

    #[test]
    fn test_compact_detection_critical_keyword() {
        let body = json!({
            "messages": [
                {"role": "user", "content": "CRITICAL: Respond with TEXT ONLY. Do NOT call any tools. Summarize this conversation."}
            ]
        });
        assert!(is_compact_request(&body));
    }

    #[test]
    fn test_compact_detection_structural_markers() {
        // Claude Code compact 特有的结构标记
        let body = json!({
            "messages": [
                {"role": "user", "content": "Summary of conversation:\n\nPending Tasks:\n- Fix bug\n\nCurrent Work:\n- Implementing feature"}
            ]
        });
        assert!(is_compact_request(&body));
    }

    #[test]
    fn test_compact_no_false_positive_on_generic_summary() {
        // 通用短语不应触发 compact 检测
        let body = json!({
            "messages": [
                {"role": "user", "content": "Your task is to create a detailed summary of the conversation so far."}
            ]
        });
        assert!(!is_compact_request(&body));
    }

    #[test]
    fn test_compact_detection_negative() {
        let body = json!({
            "messages": [
                {"role": "user", "content": "What is the weather today?"}
            ]
        });
        assert!(!is_compact_request(&body));
    }

    #[test]
    fn test_compact_detection_system_array() {
        let body = json!({
            "system": [
                {"type": "text", "text": "You are a helpful AI assistant tasked with summarizing conversations."}
            ],
            "messages": [
                {"role": "user", "content": "Summarize"}
            ]
        });
        assert!(is_compact_request(&body));
    }
}