use chrono::{DateTime, Utc};
use serde::{Deserialize, Serialize};
use utoipa::ToSchema;
use uuid::Uuid;
use validator::Validate;

// ============ 消息 DTO ============

/// 消息响应
#[derive(Debug, Serialize, ToSchema)]
pub struct MessageResp {
    pub id: Uuid,
    pub tenant_id: Uuid,
    pub template_id: Option<Uuid>,
    pub sender_id: Option<Uuid>,
    pub sender_type: String,
    pub recipient_id: Uuid,
    pub recipient_type: String,
    pub title: String,
    pub body: String,
    pub priority: String,
    pub business_type: Option<String>,
    pub business_id: Option<Uuid>,
    pub is_read: bool,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub read_at: Option<DateTime<Utc>>,
    pub is_archived: bool,
    pub status: String,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub sent_at: Option<DateTime<Utc>>,
    pub created_at: DateTime<Utc>,
    pub updated_at: DateTime<Utc>,
    pub version: i32,
}

/// 发送消息请求
#[derive(Debug, Deserialize, Validate, ToSchema)]
pub struct SendMessageReq {
    #[validate(length(min = 1, max = 200, message = "标题不能为空且不超过200字符"))]
    pub title: String,
    #[validate(length(min = 1, message = "内容不能为空"))]
    pub body: String,
    pub recipient_id: Uuid,
    #[serde(default = "default_recipient_type")]
    #[validate(custom(function = "validate_recipient_type"))]
    pub recipient_type: String,
    #[serde(default = "default_priority")]
    #[validate(custom(function = "validate_priority"))]
    pub priority: String,
    pub template_id: Option<Uuid>,
    pub business_type: Option<String>,
    pub business_id: Option<Uuid>,
}

fn validate_recipient_type(value: &str) -> Result<(), validator::ValidationError> {
    match value {
        "user" | "role" | "department" | "all" => Ok(()),
        _ => Err(validator::ValidationError::new("invalid_recipient_type")),
    }
}

fn validate_priority(value: &str) -> Result<(), validator::ValidationError> {
    match value {
        "normal" | "important" | "urgent" => Ok(()),
        _ => Err(validator::ValidationError::new("invalid_priority")),
    }
}

fn default_recipient_type() -> String {
    "user".to_string()
}

fn default_priority() -> String {
    "normal".to_string()
}

/// 消息列表查询参数
#[derive(Debug, Deserialize, ToSchema)]
pub struct MessageQuery {
    pub page: Option<u64>,
    pub page_size: Option<u64>,
    pub is_read: Option<bool>,
    pub priority: Option<String>,
    pub business_type: Option<String>,
    pub status: Option<String>,
}

impl MessageQuery {
    /// 获取安全的分页大小（上限 100）。
    pub fn safe_page_size(&self) -> u64 {
        self.page_size.unwrap_or(20).min(100)
    }
}

/// 未读消息计数响应
#[derive(Debug, Serialize, ToSchema)]
pub struct UnreadCountResp {
    pub count: i64,
}

// ============ 消息模板 DTO ============

/// 消息模板响应
#[derive(Debug, Serialize, ToSchema)]
pub struct MessageTemplateResp {
    pub id: Uuid,
    pub tenant_id: Uuid,
    pub name: String,
    pub code: String,
    pub channel: String,
    pub title_template: String,
    pub body_template: String,
    pub language: String,
    pub created_at: DateTime<Utc>,
    pub updated_at: DateTime<Utc>,
}

/// 创建消息模板请求
#[derive(Debug, Deserialize, Validate, ToSchema)]
pub struct CreateTemplateReq {
    #[validate(length(min = 1, max = 100, message = "名称不能为空且不超过100字符"))]
    pub name: String,
    #[validate(length(min = 1, max = 50, message = "编码不能为空且不超过50字符"))]
    pub code: String,
    #[serde(default = "default_channel")]
    #[validate(custom(function = "validate_channel"))]
    pub channel: String,
    #[validate(length(min = 1, max = 200, message = "标题模板不能为空"))]
    pub title_template: String,
    #[validate(length(min = 1, message = "内容模板不能为空"))]
    pub body_template: String,
    #[serde(default = "default_language")]
    pub language: String,
}

fn default_channel() -> String {
    "in_app".to_string()
}

fn validate_channel(value: &str) -> Result<(), validator::ValidationError> {
    match value {
        "in_app" | "email" | "sms" | "wechat" => Ok(()),
        _ => Err(validator::ValidationError::new("invalid_channel")),
    }
}

fn default_language() -> String {
    "zh-CN".to_string()
}

// ============ 消息订阅偏好 DTO ============

/// 消息订阅偏好响应
#[derive(Debug, Serialize, ToSchema)]
pub struct MessageSubscriptionResp {
    pub id: Uuid,
    pub tenant_id: Uuid,
    pub user_id: Uuid,
    pub notification_types: Option<serde_json::Value>,
    pub channel_preferences: Option<serde_json::Value>,
    pub dnd_enabled: bool,
    pub dnd_start: Option<String>,
    pub dnd_end: Option<String>,
    pub created_at: DateTime<Utc>,
    pub updated_at: DateTime<Utc>,
    pub version: i32,
}

/// 更新消息订阅偏好请求
#[derive(Debug, Deserialize, ToSchema)]
pub struct UpdateSubscriptionReq {
    pub notification_types: Option<serde_json::Value>,
    pub channel_preferences: Option<serde_json::Value>,
    pub dnd_enabled: Option<bool>,
    pub dnd_start: Option<String>,
    pub dnd_end: Option<String>,
    pub version: i32,
}