use axum::{extract::{State, Path, Query, Json}, http::StatusCode};
use serde::Deserialize;
use sqlx::Row;

use crate::AppState;
use super::ApiResponse;
use crate::tcp::push_to_targets;
use csm_protocol::{MessageType, UsbPolicyPayload, UsbDeviceRule};

#[derive(Debug, Deserialize)]
pub struct UsbEventListParams {
    pub device_uid: Option<String>,
    pub event_type: Option<String>,
    pub page: Option<u32>,
    pub page_size: Option<u32>,
}

pub async fn list_events(
    State(state): State<AppState>,
    Query(params): Query<UsbEventListParams>,
) -> Json<ApiResponse<serde_json::Value>> {
    let limit = params.page_size.unwrap_or(20).min(100);
    let offset = params.page.unwrap_or(1).saturating_sub(1) * limit;

    // Normalize empty strings to None
    let device_uid = params.device_uid.as_deref().filter(|s| !s.is_empty()).map(String::from);
    let event_type = params.event_type.as_deref().filter(|s| !s.is_empty()).map(String::from);

    let rows = sqlx::query(
        "SELECT id, device_uid, vendor_id, product_id, serial_number, device_name, event_type, event_time
         FROM usb_events WHERE 1=1
         AND (? IS NULL OR device_uid = ?)
         AND (? IS NULL OR event_type = ?)
         ORDER BY event_time DESC LIMIT ? OFFSET ?"
    )
    .bind(&device_uid).bind(&device_uid)
    .bind(&event_type).bind(&event_type)
    .bind(limit).bind(offset)
    .fetch_all(&state.db)
    .await;

    match rows {
        Ok(records) => {
            let items: Vec<serde_json::Value> = records.iter().map(|r| serde_json::json!({
                "id": r.get::<i64, _>("id"),
                "device_uid": r.get::<String, _>("device_uid"),
                "vendor_id": r.get::<Option<String>, _>("vendor_id"),
                "product_id": r.get::<Option<String>, _>("product_id"),
                "serial_number": r.get::<Option<String>, _>("serial_number"),
                "device_name": r.get::<Option<String>, _>("device_name"),
                "event_type": r.get::<String, _>("event_type"),
                "event_time": r.get::<String, _>("event_time"),
            })).collect();
            Json(ApiResponse::ok(serde_json::json!({
                "events": items,
                "page": params.page.unwrap_or(1),
                "page_size": limit,
            })))
        }
        Err(e) => Json(ApiResponse::internal_error("query usb events", e)),
    }
}

pub async fn list_policies(
    State(state): State<AppState>,
) -> Json<ApiResponse<serde_json::Value>> {
    let rows = sqlx::query(
        "SELECT id, name, policy_type, target_group, rules, enabled, created_at, updated_at
         FROM usb_policies ORDER BY created_at DESC LIMIT 500"
    )
    .fetch_all(&state.db)
    .await;

    match rows {
        Ok(records) => {
            let items: Vec<serde_json::Value> = records.iter().map(|r| serde_json::json!({
                "id": r.get::<i64, _>("id"),
                "name": r.get::<String, _>("name"),
                "policy_type": r.get::<String, _>("policy_type"),
                "target_group": r.get::<Option<String>, _>("target_group"),
                "rules": r.get::<String, _>("rules"),
                "enabled": r.get::<i32, _>("enabled"),
                "created_at": r.get::<String, _>("created_at"),
                "updated_at": r.get::<String, _>("updated_at"),
            })).collect();
            Json(ApiResponse::ok(serde_json::json!({
                "policies": items,
            })))
        }
        Err(e) => Json(ApiResponse::internal_error("query usb policies", e)),
    }
}

#[derive(Debug, Deserialize)]
pub struct CreatePolicyRequest {
    pub name: String,
    pub policy_type: String,
    pub target_group: Option<String>,
    pub rules: String,
    pub enabled: Option<i32>,
}

pub async fn create_policy(
    State(state): State<AppState>,
    Json(body): Json<CreatePolicyRequest>,
) -> (StatusCode, Json<ApiResponse<serde_json::Value>>) {
    let enabled = body.enabled.unwrap_or(1);

    // Input validation
    if body.name.trim().is_empty() || body.name.len() > 100 {
        return (StatusCode::BAD_REQUEST, Json(ApiResponse::error("name must be 1-100 chars")));
    }

    let result = sqlx::query(
        "INSERT INTO usb_policies (name, policy_type, target_group, rules, enabled) VALUES (?, ?, ?, ?, ?)"
    )
    .bind(&body.name)
    .bind(&body.policy_type)
    .bind(&body.target_group)
    .bind(&body.rules)
    .bind(enabled)
    .execute(&state.db)
    .await;

    match result {
        Ok(r) => {
            let new_id = r.last_insert_rowid();
            // Push USB policy to matching online clients
            if enabled == 1 {
                let payload = build_usb_policy_payload(&body.policy_type, true, &body.rules);
                let target_group = body.target_group.as_deref();
                push_to_targets(&state.db, &state.clients, MessageType::UsbPolicyUpdate, &payload, "group", target_group).await;
            }
            (StatusCode::CREATED, Json(ApiResponse::ok(serde_json::json!({
                "id": new_id,
            }))))
        }
        Err(e) => (StatusCode::INTERNAL_SERVER_ERROR, Json(ApiResponse::internal_error("create usb policy", e))),
    }
}

#[derive(Debug, Deserialize)]
pub struct UpdatePolicyRequest {
    pub name: Option<String>,
    pub policy_type: Option<String>,
    pub target_group: Option<String>,
    pub rules: Option<String>,
    pub enabled: Option<i32>,
}

pub async fn update_policy(
    State(state): State<AppState>,
    Path(id): Path<i64>,
    Json(body): Json<UpdatePolicyRequest>,
) -> Json<ApiResponse<serde_json::Value>> {
    // Fetch existing policy
    let existing = sqlx::query("SELECT * FROM usb_policies WHERE id = ?")
        .bind(id)
        .fetch_optional(&state.db)
        .await;

    let existing = match existing {
        Ok(Some(row)) => row,
        Ok(None) => return Json(ApiResponse::error("Policy not found")),
        Err(e) => return Json(ApiResponse::internal_error("query usb policy", e)),
    };

    let name = body.name.unwrap_or_else(|| existing.get::<String, _>("name"));
    let policy_type = body.policy_type.unwrap_or_else(|| existing.get::<String, _>("policy_type"));
    let target_group = body.target_group.or_else(|| existing.get::<Option<String>, _>("target_group"));
    let rules = body.rules.unwrap_or_else(|| existing.get::<String, _>("rules"));
    let enabled = body.enabled.unwrap_or_else(|| existing.get::<i32, _>("enabled"));

    let result = sqlx::query(
        "UPDATE usb_policies SET name = ?, policy_type = ?, target_group = ?, rules = ?, enabled = ?, updated_at = datetime('now') WHERE id = ?"
    )
    .bind(&name)
    .bind(&policy_type)
    .bind(&target_group)
    .bind(&rules)
    .bind(enabled)
    .bind(id)
    .execute(&state.db)
    .await;

    match result {
        Ok(_) => {
            // Push updated USB policy to matching online clients
            let payload = build_usb_policy_payload(&policy_type, enabled == 1, &rules);
            let target_group = target_group.as_deref();
            push_to_targets(&state.db, &state.clients, MessageType::UsbPolicyUpdate, &payload, "group", target_group).await;
            Json(ApiResponse::ok(serde_json::json!({"updated": true})))
        }
        Err(e) => Json(ApiResponse::internal_error("update usb policy", e)),
    }
}

pub async fn delete_policy(
    State(state): State<AppState>,
    Path(id): Path<i64>,
) -> Json<ApiResponse<serde_json::Value>> {
    // Fetch existing policy to get target info for push
    let existing = sqlx::query("SELECT target_group FROM usb_policies WHERE id = ?")
        .bind(id)
        .fetch_optional(&state.db)
        .await;

    let target_group = match existing {
        Ok(Some(row)) => row.get::<Option<String>, _>("target_group"),
        _ => return Json(ApiResponse::error("Policy not found")),
    };

    let result = sqlx::query("DELETE FROM usb_policies WHERE id = ?")
        .bind(id)
        .execute(&state.db)
        .await;

    match result {
        Ok(r) => {
            if r.rows_affected() > 0 {
                // Push disabled policy to clients
                let disabled = UsbPolicyPayload {
                    policy_type: String::new(),
                    enabled: false,
                    rules: vec![],
                };
                push_to_targets(&state.db, &state.clients, MessageType::UsbPolicyUpdate, &disabled, "group", target_group.as_deref()).await;
                Json(ApiResponse::ok(serde_json::json!({"deleted": true})))
            } else {
                Json(ApiResponse::error("Policy not found"))
            }
        }
        Err(e) => Json(ApiResponse::internal_error("delete usb policy", e)),
    }
}

/// Build a UsbPolicyPayload from raw policy fields
fn build_usb_policy_payload(policy_type: &str, enabled: bool, rules_json: &str) -> UsbPolicyPayload {
    let raw_rules: Vec<serde_json::Value> = serde_json::from_str(rules_json).unwrap_or_default();
    let rules: Vec<UsbDeviceRule> = raw_rules.iter().map(|r| UsbDeviceRule {
        vendor_id: r.get("vendor_id").and_then(|v| v.as_str().map(String::from)),
        product_id: r.get("product_id").and_then(|v| v.as_str().map(String::from)),
        serial: r.get("serial").and_then(|v| v.as_str().map(String::from)),
        device_name: r.get("device_name").and_then(|v| v.as_str().map(String::from)),
    }).collect();
    UsbPolicyPayload {
        policy_type: policy_type.to_string(),
        enabled,
        rules,
    }
}