use crate::tools::skill::{Skill, SkillSource, SkillSpec};
use std::fs;
use std::path::Path;

/// 解析 SKILL.md 文件，返回 Skill
///
/// SKILL.md 格式：
/// ```markdown
/// # Skill Name
/// Description text...
///
/// ## Risk Level
/// Low | High
///
/// ## Parameters
/// ```json
/// { ... }
/// ```
///
/// ## Execute
/// ```bash
/// command to run
/// ```
/// ```
pub fn parse_skill(skill_dir: &Path) -> Result<Skill, String> {
    let md_path = skill_dir.join("SKILL.md");
    let content =
        fs::read_to_string(&md_path).map_err(|e| format!("读取 {} 失败: {}", md_path.display(), e))?;

    let lines: Vec<&str> = content.lines().collect();
    let mut name = String::new();
    let mut description = String::new();
    let mut risk_level = String::new();
    let mut params_raw = String::new();
    let mut execute_raw = String::new();
    let mut in_params = false;
    let mut in_execute = false;
    let mut params_fence = 0;
    let mut execute_fence = 0;
    let mut desc_lines: Vec<&str> = Vec::new();
    let mut in_desc = false;

    for (i, line) in lines.iter().enumerate() {
        let trimmed = line.trim();

        // 标题行 → 技能名
        if trimmed.starts_with("# ") && !trimmed.starts_with("## ") && name.is_empty() {
            name = trimmed.trim_start_matches("# ").trim().to_string();
            continue;
        }

        // 二级标题
        if trimmed.starts_with("## ") {
            let section = trimmed.trim_start_matches("## ").trim().to_lowercase();
            match section.as_str() {
                "risk level" | "risk_level" | "risk" => {
                    in_desc = false;
                    in_params = false;
                    in_execute = false;
                }
                "parameters" | "param" => {
                    in_desc = false;
                    in_params = true;
                    in_execute = false;
                }
                "execute" | "execution" | "command" | "run" => {
                    in_desc = false;
                    in_params = false;
                    in_execute = true;
                    params_fence = 0;
                    execute_fence = 0;
                }
                _ => {
                    in_desc = false;
                    in_params = false;
                    in_execute = false;
                }
            }
            continue;
        }

        // 描述：标题和 Risk Level 之间的文本
        if !in_params && !in_execute && !trimmed.starts_with("#") && !trimmed.is_empty() {
            if name.is_empty() {
                continue;
            }
            // 检查是否已进入 Risk Level 段
            let is_risk_line = trimmed.to_lowercase().starts_with("low")
                || trimmed.to_lowercase().starts_with("high");
            if risk_level.is_empty() && is_risk_line {
                risk_level = trimmed.to_string();
                continue;
            }
            if risk_level.is_empty() {
                desc_lines.push(trimmed);
            }
            continue;
        }

        // Risk Level 值
        if !in_params && !in_execute && risk_level.is_empty() {
            let lower = trimmed.to_lowercase();
            if lower == "low" || lower == "high" {
                risk_level = trimmed.to_string();
                continue;
            }
        }

        // Parameters: JSON 代码块
        if in_params {
            if trimmed.starts_with("```") {
                params_fence += 1;
                if params_fence == 2 {
                    in_params = false;
                }
                continue;
            }
            if params_fence == 1 {
                if !params_raw.is_empty() {
                    params_raw.push('\n');
                }
                params_raw.push_str(trimmed);
            }
            continue;
        }

        // Execute: shell 命令
        if in_execute {
            if trimmed.starts_with("```") {
                execute_fence += 1;
                if execute_fence == 2 {
                    in_execute = false;
                }
                continue;
            }
            if execute_fence == 1 {
                // 跳过 shebang 行
                if trimmed.starts_with("#!/") {
                    continue;
                }
                if !execute_raw.is_empty() {
                    execute_raw.push('\n');
                }
                execute_raw.push_str(trimmed);
            }
            continue;
        }
    }

    // 验证
    if name.is_empty() {
        return Err(format!("{}: 未找到技能名称 (# Title)", md_path.display()));
    }

    description = desc_lines.join(" ").trim().to_string();

    let risk = match risk_level.to_lowercase().trim() {
        "high" => crate::tools::skill::RiskLevel::High,
        _ => crate::tools::skill::RiskLevel::Low,
    };

    // 解析参数 JSON
    let parameters: serde_json::Value = if params_raw.is_empty() {
        serde_json::json!({
            "type": "object",
            "properties": {}
        })
    } else {
        serde_json::from_str(&params_raw).unwrap_or_else(|_| {
            serde_json::json!({
                "type": "object",
                "properties": {}
            })
        })
    };

    // 执行命令（去掉首尾空白）
    let execute_command = execute_raw.trim().to_string();
    if execute_command.is_empty() {
        return Err(format!("{}: 未找到 Execute 命令", md_path.display()));
    }

    let spec = SkillSpec {
        name,
        description,
        risk_level: risk,
        parameters,
        timeout_secs: 30,
    };

    Ok(Skill::new(
        spec,
        // 先设成 User，由调用方修正
        SkillSource::User,
        skill_dir.to_path_buf(),
        execute_command,
    ))
}

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

    #[test]
    fn test_load_all_system_skills() {
        let rt = tokio::runtime::Runtime::new().unwrap();
        let result = rt.block_on(crate::tools::registry::SkillRegistry::load(
            "resources/skills",
            "/nonexistent",
        ));
        match result {
            Ok(registry) => {
                assert_eq!(registry.count(), 8, "应该有 8 个系统技能");
                let names: Vec<&str> = registry.list_specs().iter().map(|s| s.name.as_str()).collect();
                println!("已加载技能: {:?}", names);
                assert!(names.contains(&"manage_memos"));
                assert!(names.contains(&"get_current_datetime"));
                assert!(names.contains(&"query_weather"));
                assert!(names.contains(&"search_web"));
                assert!(names.contains(&"email"));
                assert!(names.contains(&"execute_shell"));
                assert!(names.contains(&"list_scheduled_tasks"));
                assert!(names.contains(&"manage_scheduled_task"));
            }
            Err(errors) => {
                for e in &errors {
                    eprintln!("加载失败: {}", e);
                }
                panic!("技能加载失败");
            }
        }
    }

    #[test]
    fn test_parse_basic_skill() {
        let dir = std::env::temp_dir().join("ias-test-skill");
        fs::create_dir_all(&dir).ok();
        let mut f = fs::File::create(dir.join("SKILL.md")).unwrap();
        write!(
            f,
            r#"# Get Current Datetime

获取当前日期时间（北京时间 UTC+8）。

## Risk Level
Low

## Parameters
```json
{{
  "type": "object",
  "properties": {{
    "format": {{
      "type": "string",
      "description": "full | date | time"
    }}
  }}
}}
```

## Execute
```bash
date '+%Y-%m-%d %H:%M:%S'
```
"#
        )
        .unwrap();

        let skill = parse_skill(&dir).unwrap();
        assert_eq!(skill.spec.name, "Get Current Datetime");
        assert!(skill.spec.description.contains("日期时间"));
        assert_eq!(skill.spec.risk_level, crate::tools::skill::RiskLevel::Low);
        assert!(!skill.execute_command.is_empty());
        assert!(skill.execute_command.contains("date"));

        fs::remove_dir_all(&dir).ok();
    }
}