//! 从应用目录 `resources/data/agent` 读取代理编号。

use std::path::{Path, PathBuf};

use serde_json::Value;
use tauri::{AppHandle, Manager, path::BaseDirectory};

/// 相对可执行文件目录的代理配置路径：`resources/data/agent`。
pub const AGENT_RESOURCE_RELATIVE: &[&str] = &["resources", "data", "agent"];

/// 开发时源码树中的代理配置路径。
pub const AGENT_DEV_RELATIVE: &str = "src-tauri/resources/data/agent";

pub fn read_agent_id_file(path: &Path) -> Option<i64> {
    let content = std::fs::read_to_string(path).ok()?;
    parse_agent_id_content(&content)
}

/// 解析代理配置文件路径（打包资源 → 应用目录 → 开发目录）。
pub fn resolve_agent_id_path(handle: &AppHandle) -> Option<PathBuf> {
    if let Ok(path) = handle.path().resolve("data/agent", BaseDirectory::Resource) {
        if path.is_file() {
            return Some(path);
        }
    }
    locate_agent_id_file()
}

/// 读取当前应用的代理编号；无配置文件时返回 `None`。
pub fn load_agent_id(handle: &AppHandle) -> Option<i64> {
    resolve_agent_id_path(handle).and_then(|path| read_agent_id_file(&path))
}

/// 按可执行文件旁 `resources/data/agent` 或开发目录定位配置文件。
pub fn locate_agent_id_file() -> Option<PathBuf> {
    if let Ok(path) = std::env::var("AICLIENT_AGENT_FILE") {
        let custom = PathBuf::from(path);
        if custom.is_file() {
            return Some(custom);
        }
    }

    if let Ok(exe) = std::env::current_exe() {
        if let Some(dir) = exe.parent() {
            let bundled = dir.join(path_from_parts(AGENT_RESOURCE_RELATIVE));
            if bundled.is_file() {
                return Some(bundled);
            }
        }
    }

    let dev = PathBuf::from(AGENT_DEV_RELATIVE);
    if dev.is_file() {
        return Some(dev);
    }

    None
}

fn path_from_parts(parts: &[&str]) -> PathBuf {
    let mut path = PathBuf::new();
    for part in parts {
        path.push(part);
    }
    path
}

fn parse_agent_id_content(content: &str) -> Option<i64> {
    let trimmed = content.trim();
    if trimmed.is_empty() {
        return None;
    }

    if let Ok(value) = serde_json::from_str::<Value>(trimmed) {
        if let Some(id) = value.get("agent_id").and_then(|v| v.as_i64()) {
            if id >= 1 {
                return Some(id);
            }
        }
        if let Some(id) = value.as_i64() {
            if id >= 1 {
                return Some(id);
            }
        }
    }

    let first_line = trimmed.lines().next()?.trim();
    let id: i64 = first_line.parse().ok()?;
    if id >= 1 {
        Some(id)
    } else {
        None
    }
}

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

    #[test]
    fn parse_integer_line() {
        assert_eq!(parse_agent_id_content("5\n"), Some(5));
    }

    #[test]
    fn parse_json_object() {
        assert_eq!(parse_agent_id_content(r#"{"agent_id":7}"#), Some(7));
    }

    #[test]
    fn invalid_returns_none() {
        assert_eq!(parse_agent_id_content("abc"), None);
        assert_eq!(parse_agent_id_content(""), None);
    }
}