use axum::{
    body::Body,
    extract::State,
    http::StatusCode,
    response::{IntoResponse, Response},
};
use axum_extra::extract::Multipart;
use chrono::Local;
use serde_json::json;
use std::path::PathBuf;
use std::sync::Arc;
use tokio::fs;
use uuid::Uuid;

use crate::handler::AppState;

/// 文件上传结果
#[derive(Debug, serde::Serialize)]
pub struct UploadResult {
    pub success: bool,
    pub files: Vec<FileInfo>,
    pub message: String,
}

/// 单个文件信息
#[derive(Debug, serde::Serialize)]
pub struct FileInfo {
    pub original_name: String,
    pub stored_name: String,
    pub path: String,
    pub size: usize,
    pub content_type: Option<String>,
}

impl UploadResult {
    pub fn success(files: Vec<FileInfo>) -> Self {
        UploadResult {
            success: true,
            files,
            message: "Files uploaded successfully".to_string(),
        }
    }

    pub fn error(message: String) -> Self {
        UploadResult {
            success: false,
            files: vec![],
            message,
        }
    }
}

impl IntoResponse for UploadResult {
    fn into_response(self) -> Response {
        let status = if self.success {
            StatusCode::OK
        } else {
            StatusCode::BAD_REQUEST
        };

        let body = serde_json::to_string(&self).unwrap_or_else(|_| {
            json!({
                "success": false,
                "files": [],
                "message": "Failed to serialize response"
            })
            .to_string()
        });

        Response::builder()
            .status(status)
            .header("content-type", "application/json")
            .body(Body::from(body))
            .unwrap()
    }
}

/// 处理文件上传
pub async fn upload_handler(
    State(_state): State<Arc<AppState>>,
    mut multipart: Multipart,
) -> impl IntoResponse {
    let mut uploaded_files = Vec::new();

    // 确保 storage 目录存在
    let storage_root = PathBuf::from("storage");
    if let Err(e) = fs::create_dir_all(&storage_root).await {
        return UploadResult::error(format!("Failed to create storage directory: {}", e));
    }

    // 创建按日期分类的子目录
    let date_dir = Local::now().format("%Y-%m-%d").to_string();
    let upload_dir = storage_root.join(&date_dir);
    if let Err(e) = fs::create_dir_all(&upload_dir).await {
        return UploadResult::error(format!("Failed to create upload directory: {}", e));
    }

    // 处理每个上传的字段
    while let Some(field) = multipart.next_field().await.unwrap_or(None) {
        // 获取文件名
        let original_name = field
            .file_name()
            .map(|s| s.to_string())
            .unwrap_or_else(|| "unknown".to_string());

        // 获取内容类型
        let content_type = field.content_type().map(|s| s.to_string());

        // 读取文件数据
        let data = match field.bytes().await {
            Ok(d) => d,
            Err(e) => {
                eprintln!("Failed to read file data: {}", e);
                continue;
            }
        };

        // 生成唯一文件名，保留原始扩展名
        let extension = std::path::Path::new(&original_name)
            .extension()
            .and_then(|s| s.to_str())
            .map(|s| format!(".{}", s))
            .unwrap_or_default();

        let stored_name = format!("{}{}", Uuid::new_v4(), extension);
        let file_path = upload_dir.join(&stored_name);

        // 保存文件
        match fs::write(&file_path, &data).await {
            Ok(_) => {
                uploaded_files.push(FileInfo {
                    original_name: original_name.clone(),
                    stored_name: stored_name.clone(),
                    path: format!("storage/{}/{}", date_dir, stored_name),
                    size: data.len(),
                    content_type,
                });
            }
            Err(e) => {
                eprintln!("Failed to save file {}: {}", original_name, e);
            }
        }
    }

    if uploaded_files.is_empty() {
        UploadResult::error("No files were uploaded".to_string())
    } else {
        UploadResult::success(uploaded_files)
    }
}