use chrono::{DateTime, Utc};
use serde::{Deserialize, Serialize};

// ============================================================================
// API Response Types
// ============================================================================

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct ApiResponse<T> {
    pub success: bool,
    pub data: Option<T>,
    pub error: Option<String>,
    pub message: Option<String>,
}

/// Format backend error payloads into a readable string.
pub fn api_error_detail(error: &Option<String>) -> String {
    error
        .as_ref()
        .map(String::from)
        .unwrap_or_else(|| "Unknown backend error".to_string())
}

// ============================================================================
// Authentication
// ============================================================================

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct LoginRequest {
    pub method: String,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub username: Option<String>,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub password: Option<String>,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub pin: Option<String>,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub login_string: Option<String>,
}

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct LoginResponse {
    pub success: bool,
    pub token: String,
    pub user: UserInfo,
}

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct UserInfo {
    pub id: i32,
    pub username: String,
    pub role: String,
    pub power: i32,
}

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct SessionStatus {
    pub valid: bool,
    pub user: Option<UserInfo>,
    pub expires_at: Option<DateTime<Utc>>,
    pub message: Option<String>,
}

// ============================================================================
// Permissions
// ============================================================================

#[allow(dead_code)]
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct PermissionsResponse {
    pub user: UserInfo,
    pub user_settings_access: String,
    pub permissions: serde_json::Value, // Flexible permissions structure
    pub security_clearance: Option<String>,
}

// ============================================================================
// Preferences
// ============================================================================

#[allow(dead_code)]
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct PreferencesRequest {
    pub action: String, // "get", "set", "reset"
    #[serde(skip_serializing_if = "Option::is_none")]
    pub user_id: Option<i32>,
    #[serde(skip_serializing_if = "Option::is_none")]
    #[serde(rename = "preferences")]
    pub preferences: Option<serde_json::Value>,
}

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct PreferencesResponse {
    pub user_id: i32,
    pub preferences: serde_json::Value,
}

// ============================================================================
// Query Operations
// ============================================================================

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct QueryRequest {
    pub action: String, // "select", "insert", "update", "delete", "count"
    pub table: String,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub columns: Option<Vec<String>>,
    #[serde(skip_serializing_if = "Option::is_none")]
    #[serde(rename = "data")]
    pub data: Option<serde_json::Value>,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub r#where: Option<serde_json::Value>,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub filter: Option<serde_json::Value>,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub order_by: Option<Vec<OrderBy>>,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub limit: Option<u32>,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub offset: Option<u32>,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub joins: Option<Vec<Join>>,
}

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct OrderBy {
    pub column: String,
    pub direction: String, // "ASC" or "DESC"
}

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct Join {
    pub table: String,
    pub on: String,
    #[serde(rename = "type")]
    pub join_type: String, // "INNER", "LEFT", "RIGHT" - serialized as "type" for API
}

// ============================================================================
// Asset Models
// ============================================================================

#[allow(dead_code)]
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct Asset {
    pub id: Option<i32>,
    pub asset_tag: String,
    pub asset_numeric_id: Option<i32>,
    pub asset_type: String, // "N", "T", "C"
    pub name: String,
    pub description: Option<String>,
    pub category_id: Option<i32>,
    pub zone_id: Option<i32>,
    pub zone_plus: Option<String>, // "Exact", "Clarify", "Deployed"
    pub zone_note: Option<String>,
    pub manufacturer: Option<String>,
    pub model: Option<String>,
    pub serial_number: Option<String>,
    pub status: String, // "Good", "Faulty", "Scrapped", "Missing"
    pub price: Option<f64>,
    pub purchase_date: Option<String>,
    pub warranty_expiry: Option<String>,
    pub supplier_id: Option<i32>,
    pub lendable: bool,
    pub lending_status: Option<String>, // "Available", "Borrowed", "Deployed", "Overdue"
    pub asset_image: Option<String>,
    pub notes: Option<String>,
    pub created_by: Option<i32>,
    pub created_date: Option<DateTime<Utc>>,
    pub last_modified_by: Option<i32>,
    pub last_modified_date: Option<DateTime<Utc>>,
}

// ============================================================================
// Borrower Models
// ============================================================================

#[allow(dead_code)]
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct Borrower {
    pub id: Option<i32>,
    pub borrower_code: String,
    pub name: String,
    pub email: Option<String>,
    pub phone: Option<String>,
    pub borrower_type: String, // "Student", "Faculty", "Staff", "External"
    pub department: Option<String>,
    pub banned: bool,
    pub unban_fine: Option<f64>,
    pub ban_reason: Option<String>,
    pub notes: Option<String>,
}

// ============================================================================
// Category & Zone Models
// ============================================================================

#[allow(dead_code)]
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct Category {
    pub id: Option<i32>,
    pub category_code: String,
    pub name: String,
    pub description: Option<String>,
}

#[allow(dead_code)]
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct Zone {
    pub id: Option<i32>,
    pub zone_code: String,
    pub name: String,
    pub parent_zone_id: Option<i32>,
    pub level: i32,
    pub description: Option<String>,
}

// ============================================================================
// Lending History
// ============================================================================

#[allow(dead_code)]
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct LendingHistory {
    pub id: Option<i32>,
    pub asset_id: i32,
    pub borrower_id: i32,
    pub checkout_date: DateTime<Utc>,
    pub due_date: String,
    pub return_date: Option<DateTime<Utc>>,
    pub status: String, // "Active", "Returned", "Overdue", "Lost"
    pub checkout_condition: Option<String>,
    pub return_condition: Option<String>,
    pub notes: Option<String>,
    pub checked_out_by: Option<i32>,
    pub checked_in_by: Option<i32>,
}

// ============================================================================
// Issue Tracker
// ============================================================================

#[allow(dead_code)]
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct Issue {
    pub id: Option<i32>,
    pub issue_type: String, // "Asset Issue", "Borrower Issue", "System Issue"
    pub asset_id: Option<i32>,
    pub borrower_id: Option<i32>,
    pub title: String,
    pub description: Option<String>,
    pub severity: String, // "Low", "Medium", "High", "Critical"
    pub priority: String, // "Low", "Medium", "High", "Critical"
    pub status: String,   // "Open", "In Progress", "On Hold", "Resolved", "Closed"
    pub solution: Option<String>,
    pub solution_plus: Option<String>,
    pub auto_detected: bool,
    pub detection_trigger: Option<String>,
    pub reported_by: Option<i32>,
    pub reported_date: Option<DateTime<Utc>>,
    pub resolved_by: Option<i32>,
    pub resolved_date: Option<DateTime<Utc>>,
}

// ============================================================================
// Dashboard Stats
// ============================================================================

#[derive(Debug, Clone, Serialize, Deserialize, Default)]
pub struct DashboardStats {
    pub total_assets: i32,
    pub okay_items: i32,      // All items with status "Good"
    pub attention_items: i32, // Faulty, Missing, Overdue, Attention, etc.
}