use axum::{extract::{State, Path, Query}, Json};
use serde::{Deserialize, Serialize};
use sqlx::Row;
use crate::AppState;
use super::{ApiResponse, Pagination};

/// GET /api/devices/:uid/health-score
pub async fn get_health_score(
    State(state): State<AppState>,
    Path(uid): Path<String>,
) -> Json<ApiResponse<serde_json::Value>> {
    match crate::health::get_device_score(&state.db, &uid).await {
        Ok(Some(score)) => Json(ApiResponse::ok(score)),
        Ok(None) => Json(ApiResponse::error("No health score available")),
        Err(e) => Json(ApiResponse::internal_error("health score", e)),
    }
}

/// GET /api/dashboard/health-overview
pub async fn health_overview(
    State(state): State<AppState>,
) -> Json<ApiResponse<serde_json::Value>> {
    match crate::health::get_health_overview(&state.db).await {
        Ok(overview) => Json(ApiResponse::ok(overview)),
        Err(e) => Json(ApiResponse::internal_error("health overview", e)),
    }
}

#[derive(Debug, Deserialize)]
pub struct DeviceListParams {
    pub status: Option<String>,
    pub group: Option<String>,
    pub search: Option<String>,
    pub page: Option<u32>,
    pub page_size: Option<u32>,
}

#[derive(Debug, Serialize, sqlx::FromRow)]
pub struct DeviceRow {
    pub id: i64,
    pub device_uid: String,
    pub hostname: String,
    pub ip_address: String,
    pub mac_address: Option<String>,
    pub os_version: Option<String>,
    pub client_version: Option<String>,
    pub status: String,
    pub last_heartbeat: Option<String>,
    pub registered_at: Option<String>,
    pub group_name: Option<String>,
    #[sqlx(default)]
    pub health_score: Option<i32>,
    #[sqlx(default)]
    pub health_level: Option<String>,
}

pub async fn list(
    State(state): State<AppState>,
    Query(params): Query<DeviceListParams>,
) -> 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 (Axum deserializes `status=` as Some(""))
    let status = params.status.as_deref().filter(|s| !s.is_empty()).map(String::from);
    let group = params.group.as_deref().filter(|s| !s.is_empty()).map(String::from);
    let search = params.search.as_deref().filter(|s| !s.is_empty()).map(String::from);

    let devices = sqlx::query_as::<_, DeviceRow>(
        "SELECT d.id, d.device_uid, d.hostname, d.ip_address, d.mac_address, d.os_version, d.client_version,
                d.status, d.last_heartbeat, d.registered_at, d.group_name,
                h.score as health_score, h.level as health_level
         FROM devices d
         LEFT JOIN device_health_scores h ON h.device_uid = d.device_uid
         WHERE 1=1
         AND (? IS NULL OR d.status = ?)
         AND (? IS NULL OR d.group_name = ?)
         AND (? IS NULL OR d.hostname LIKE '%' || ? || '%' OR d.ip_address LIKE '%' || ? || '%')
         ORDER BY d.registered_at DESC LIMIT ? OFFSET ?"
    )
    .bind(&status).bind(&status)
    .bind(&group).bind(&group)
    .bind(&search).bind(&search).bind(&search)
    .bind(limit).bind(offset)
    .fetch_all(&state.db)
    .await;

    let total: i64 = sqlx::query_scalar(
        "SELECT COUNT(*) FROM devices WHERE 1=1
         AND (? IS NULL OR status = ?)
         AND (? IS NULL OR group_name = ?)
         AND (? IS NULL OR hostname LIKE '%' || ? || '%' OR ip_address LIKE '%' || ? || '%')"
    )
    .bind(&status).bind(&status)
    .bind(&group).bind(&group)
    .bind(&search).bind(&search).bind(&search)
    .fetch_one(&state.db)
    .await
    .unwrap_or(0);

    match devices {
        Ok(rows) => Json(ApiResponse::ok(serde_json::json!({
            "devices": rows,
            "total": total,
            "page": params.page.unwrap_or(1),
            "page_size": limit,
        }))),
        Err(e) => Json(ApiResponse::internal_error("query devices", e)),
    }
}

pub async fn get_detail(
    State(state): State<AppState>,
    Path(uid): Path<String>,
) -> Json<ApiResponse<serde_json::Value>> {
    let device = sqlx::query_as::<_, DeviceRow>(
        "SELECT id, device_uid, hostname, ip_address, mac_address, os_version, client_version,
                status, last_heartbeat, registered_at, group_name
         FROM devices WHERE device_uid = ?"
    )
    .bind(&uid)
    .fetch_optional(&state.db)
    .await;

    match device {
        Ok(Some(d)) => Json(ApiResponse::ok(serde_json::to_value(d).unwrap_or_default())),
        Ok(None) => Json(ApiResponse::error("Device not found")),
        Err(e) => Json(ApiResponse::internal_error("query devices", e)),
    }
}

#[derive(Debug, Serialize, sqlx::FromRow)]
struct StatusRow {
    pub cpu_usage: f64,
    pub memory_usage: f64,
    pub memory_total_mb: i64,
    pub disk_usage: f64,
    pub disk_total_mb: i64,
    pub network_rx_rate: i64,
    pub network_tx_rate: i64,
    pub running_procs: i32,
    pub top_processes: Option<String>,
    pub reported_at: String,
}

pub async fn get_status(
    State(state): State<AppState>,
    Path(uid): Path<String>,
) -> Json<ApiResponse<serde_json::Value>> {
    let status = sqlx::query_as::<_, StatusRow>(
        "SELECT cpu_usage, memory_usage, memory_total_mb, disk_usage, disk_total_mb,
                network_rx_rate, network_tx_rate, running_procs, top_processes, reported_at
         FROM device_status WHERE device_uid = ?"
    )
    .bind(&uid)
    .fetch_optional(&state.db)
    .await;

    match status {
        Ok(Some(s)) => {
            let mut val = serde_json::to_value(&s).unwrap_or_default();
            // Parse top_processes JSON string back to array
            if let Some(tp_str) = &s.top_processes {
                if let Ok(tp) = serde_json::from_str::<serde_json::Value>(tp_str) {
                    val["top_processes"] = tp;
                }
            }
            Json(ApiResponse::ok(val))
        }
        Ok(None) => Json(ApiResponse::error("No status data found")),
        Err(e) => Json(ApiResponse::internal_error("query devices", e)),
    }
}

pub async fn get_history(
    State(state): State<AppState>,
    Path(uid): Path<String>,
    Query(page): Query<Pagination>,
) -> Json<ApiResponse<serde_json::Value>> {
    let offset = page.offset();
    let limit = page.limit();

    let rows = sqlx::query(
        "SELECT cpu_usage, memory_usage, disk_usage, running_procs, reported_at
         FROM device_status_history WHERE device_uid = ?
         ORDER BY reported_at DESC LIMIT ? OFFSET ?"
    )
    .bind(&uid)
    .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!({
                    "cpu_usage": r.get::<f64, _>("cpu_usage"),
                    "memory_usage": r.get::<f64, _>("memory_usage"),
                    "disk_usage": r.get::<f64, _>("disk_usage"),
                    "running_procs": r.get::<i32, _>("running_procs"),
                    "reported_at": r.get::<String, _>("reported_at"),
                })
            }).collect();
            Json(ApiResponse::ok(serde_json::json!({
                "history": items,
                "page": page.page.unwrap_or(1),
                "page_size": limit,
            })))
        }
        Err(e) => Json(ApiResponse::internal_error("query devices", e)),
    }
}

pub async fn remove(
    State(state): State<AppState>,
    Path(uid): Path<String>,
) -> Json<ApiResponse<()>> {
    // Delete device and all associated data in a transaction
    let mut tx = match state.db.begin().await {
        Ok(tx) => tx,
        Err(e) => return Json(ApiResponse::internal_error("begin transaction", e)),
    };

    // Delete status history
    if let Err(e) = sqlx::query("DELETE FROM device_status_history WHERE device_uid = ?")
        .bind(&uid)
        .execute(&mut *tx)
        .await
    {
        return Json(ApiResponse::internal_error("remove device history", e));
    }

    // Delete current status
    if let Err(e) = sqlx::query("DELETE FROM device_status WHERE device_uid = ?")
        .bind(&uid)
        .execute(&mut *tx)
        .await
    {
        return Json(ApiResponse::internal_error("remove device status", e));
    }

    // Delete plugin-related data
    let cleanup_tables = [
        "hardware_assets",
        "software_assets",
        "asset_changes",
        "usb_events",
        "usb_file_operations",
        "usage_daily",
        "app_usage_daily",
        "software_violations",
        "web_access_log",
        "popup_block_stats",
        "disk_encryption_status",
        "disk_encryption_alerts",
        "print_events",
        "clipboard_violations",
        "behavior_metrics",
        "anomaly_alerts",
        "device_health_scores",
        "patch_status",
    ];
    for table in &cleanup_tables {
        // Safety: table names are hardcoded constants above, not user input.
        // Parameterized ? is used for device_uid.
        debug_assert!(table.chars().all(|c| c.is_ascii_alphanumeric() || c == '_'),
            "BUG: table name contains unexpected characters: {}", table);
        if let Err(e) = sqlx::query(&format!("DELETE FROM {} WHERE device_uid = ?", table))
            .bind(&uid)
            .execute(&mut *tx)
            .await
        {
            tracing::warn!("Failed to clean {} for device {}: {}", table, uid, e);
        }
    }

    // Finally delete the device itself
    let delete_result = sqlx::query("DELETE FROM devices WHERE device_uid = ?")
        .bind(&uid)
        .execute(&mut *tx)
        .await;

    match delete_result {
        Ok(r) if r.rows_affected() > 0 => {
            if let Err(e) = tx.commit().await {
                return Json(ApiResponse::internal_error("commit device deletion", e));
            }

            // Send self-destruct command AFTER successful commit
            let frame = csm_protocol::Frame::new_json(
                csm_protocol::MessageType::ConfigUpdate,
                &serde_json::json!({"type": "SelfDestruct"}),
            ).ok();

            if let Some(frame) = frame {
                state.clients.send_to(&uid, frame.encode()).await;
            }

            state.clients.unregister(&uid).await;
            tracing::info!(device_uid = %uid, "Device and all associated data deleted");
            Json(ApiResponse::ok(()))
        }
        Ok(_) => Json(ApiResponse::error("Device not found")),
        Err(e) => Json(ApiResponse::internal_error("remove device", e)),
    }
}