use axum::{
    extract::{Path, Query, State},
    http::StatusCode,
    response::IntoResponse,
    Json,
};
use serde::{Deserialize, Serialize};
use uuid::Uuid;
use validator::Validate;

use plc_platform_core::util::{
    pagination::{PaginatedResponse, PaginationParams},
    response::ApiErr,
};
use crate::AppState;

async fn notify_units(
    state: &AppState,
    unit_ids: impl IntoIterator<Item = Uuid>,
) {
    let mut seen = std::collections::HashSet::new();
    for unit_id in unit_ids {
        if seen.insert(unit_id) {
            state.control_runtime.notify_unit(unit_id).await;
        }
    }
}

#[derive(Deserialize, Validate)]
pub struct GetEquipmentListQuery {
    #[validate(length(min = 1, max = 100))]
    pub keyword: Option<String>,
    #[serde(flatten)]
    pub pagination: PaginationParams,
}

#[derive(Serialize)]
pub struct SignalRolePoint {
    pub point_id: uuid::Uuid,
    pub signal_role: String,
    pub point_monitor: Option<crate::telemetry::PointMonitorInfo>,
}

#[derive(Serialize)]
pub struct EquipmentListItem {
    #[serde(flatten)]
    pub equipment: plc_platform_core::model::Equipment,
    pub point_count: i64,
    pub role_points: Vec<SignalRolePoint>,
}

pub async fn get_equipment_list(
    State(state): State<AppState>,
    Query(query): Query<GetEquipmentListQuery>,
) -> Result<impl IntoResponse, ApiErr> {
    query.validate()?;

    let total = crate::service::get_equipment_count(&state.pool, query.keyword.as_deref()).await?;
    let items = crate::service::get_equipment_paginated(
        &state.pool,
        query.keyword.as_deref(),
        query.pagination.page_size,
        query.pagination.offset(),
    )
    .await?;

    let equipment_ids: Vec<uuid::Uuid> = items.iter().map(|item| item.equipment.id).collect();
    let role_point_rows =
        crate::service::get_signal_role_points_batch(&state.pool, &equipment_ids).await?;

    let monitor_guard = state
        .connection_manager
        .get_point_monitor_data_read_guard()
        .await;

    let mut role_points_map: std::collections::HashMap<uuid::Uuid, Vec<SignalRolePoint>> =
        std::collections::HashMap::new();
    for rp in role_point_rows {
        role_points_map
            .entry(rp.equipment_id)
            .or_default()
            .push(SignalRolePoint {
                point_id: rp.point_id,
                signal_role: rp.signal_role,
                point_monitor: monitor_guard.get(&rp.point_id).cloned(),
            });
    }

    let data = items
        .into_iter()
        .map(|item| {
            let equipment_id = item.equipment.id;
            EquipmentListItem {
                equipment: item.equipment,
                point_count: item.point_count,
                role_points: role_points_map.remove(&equipment_id).unwrap_or_default(),
            }
        })
        .collect::<Vec<_>>();

    Ok(Json(PaginatedResponse::new(
        data,
        total,
        query.pagination.page,
        query.pagination.page_size,
    )))
}

pub async fn get_equipment(
    State(state): State<AppState>,
    Path(equipment_id): Path<Uuid>,
) -> Result<impl IntoResponse, ApiErr> {
    let equipment = crate::service::get_equipment_by_id(&state.pool, equipment_id).await?;

    match equipment {
        Some(item) => Ok(Json(item)),
        None => Err(ApiErr::NotFound("Equipment not found".to_string(), None)),
    }
}

pub async fn get_equipment_points(
    State(state): State<AppState>,
    Path(equipment_id): Path<Uuid>,
) -> Result<impl IntoResponse, ApiErr> {
    let exists = crate::service::get_equipment_by_id(&state.pool, equipment_id).await?;
    if exists.is_none() {
        return Err(ApiErr::NotFound("Equipment not found".to_string(), None));
    }

    let points = crate::service::get_points_by_equipment_id(&state.pool, equipment_id).await?;
    Ok(Json(points))
}

#[derive(Debug, Deserialize, Validate)]
pub struct CreateEquipmentReq {
    pub unit_id: Option<Uuid>,
    #[validate(length(min = 1, max = 100))]
    pub code: String,
    #[validate(length(min = 1, max = 100))]
    pub name: String,
    pub kind: Option<String>,
    pub description: Option<String>,
}

#[derive(Debug, Deserialize, Validate)]
pub struct UpdateEquipmentReq {
    pub unit_id: Option<Option<Uuid>>,
    #[validate(length(min = 1, max = 100))]
    pub code: Option<String>,
    #[validate(length(min = 1, max = 100))]
    pub name: Option<String>,
    pub kind: Option<String>,
    pub description: Option<String>,
}

#[derive(Debug, Deserialize, Validate)]
pub struct BatchSetEquipmentUnitReq {
    pub equipment_ids: Vec<Uuid>,
    pub unit_id: Option<Uuid>,
}

pub async fn create_equipment(
    State(state): State<AppState>,
    Json(payload): Json<CreateEquipmentReq>,
) -> Result<impl IntoResponse, ApiErr> {
    payload.validate()?;

    let exists = crate::service::get_equipment_by_code(&state.pool, &payload.code).await?;
    if exists.is_some() {
        return Err(ApiErr::BadRequest(
            "Equipment code already exists".to_string(),
            None,
        ));
    }

    if let Some(unit_id) = payload.unit_id {
        let unit_exists = crate::service::get_unit_by_id(&state.pool, unit_id).await?;
        if unit_exists.is_none() {
            return Err(ApiErr::NotFound("Unit not found".to_string(), None));
        }
    }

    let equipment_id = crate::service::create_equipment(
        &state.pool,
        payload.unit_id,
        &payload.code,
        &payload.name,
        payload.kind.as_deref(),
        payload.description.as_deref(),
    )
    .await?;

    if let Some(unit_id) = payload.unit_id {
        notify_units(&state, [unit_id]).await;
    }

    Ok((
        StatusCode::CREATED,
        Json(serde_json::json!({
            "id": equipment_id,
            "ok_msg": "Equipment created successfully"
        })),
    ))
}

pub async fn update_equipment(
    State(state): State<AppState>,
    Path(equipment_id): Path<Uuid>,
    Json(payload): Json<UpdateEquipmentReq>,
) -> Result<impl IntoResponse, ApiErr> {
    payload.validate()?;

    if payload.unit_id.is_none()
        && payload.code.is_none()
        && payload.name.is_none()
        && payload.kind.is_none()
        && payload.description.is_none()
    {
        return Ok(Json(serde_json::json!({"ok_msg": "No fields to update"})));
    }

    let exists = crate::service::get_equipment_by_id(&state.pool, equipment_id).await?;
    let existing_equipment = if let Some(equipment) = exists {
        equipment
    } else {
        return Err(ApiErr::NotFound("Equipment not found".to_string(), None));
    };

    if let Some(Some(unit_id)) = payload.unit_id {
        let unit_exists = crate::service::get_unit_by_id(&state.pool, unit_id).await?;
        if unit_exists.is_none() {
            return Err(ApiErr::NotFound("Unit not found".to_string(), None));
        }
    }

    if let Some(code) = payload.code.as_deref() {
        let duplicate = crate::service::get_equipment_by_code(&state.pool, code).await?;
        if duplicate
            .as_ref()
            .is_some_and(|item| item.id != equipment_id)
        {
            return Err(ApiErr::BadRequest(
                "Equipment code already exists".to_string(),
                None,
            ));
        }
    }

    crate::service::update_equipment(
        &state.pool,
        equipment_id,
        payload.unit_id,
        payload.code.as_deref(),
        payload.name.as_deref(),
        payload.kind.as_deref(),
        payload.description.as_deref(),
    )
    .await?;

    let mut unit_ids = Vec::new();
    if let Some(unit_id) = existing_equipment.unit_id {
        unit_ids.push(unit_id);
    }
    let next_unit_id = match payload.unit_id {
        Some(next) => next,
        None => existing_equipment.unit_id,
    };
    if let Some(unit_id) = next_unit_id {
        unit_ids.push(unit_id);
    }
    notify_units(&state, unit_ids).await;

    Ok(Json(serde_json::json!({
        "ok_msg": "Equipment updated successfully"
    })))
}

pub async fn batch_set_equipment_unit(
    State(state): State<AppState>,
    Json(payload): Json<BatchSetEquipmentUnitReq>,
) -> Result<impl IntoResponse, ApiErr> {
    payload.validate()?;

    if payload.equipment_ids.is_empty() {
        return Err(ApiErr::BadRequest(
            "equipment_ids cannot be empty".to_string(),
            None,
        ));
    }

    if let Some(unit_id) = payload.unit_id {
        let unit_exists = crate::service::get_unit_by_id(&state.pool, unit_id).await?;
        if unit_exists.is_none() {
            return Err(ApiErr::NotFound("Unit not found".to_string(), None));
        }
    }

    let before_unit_ids =
        crate::service::get_unit_ids_by_equipment_ids(&state.pool, &payload.equipment_ids).await?;

    let updated_count = crate::service::batch_set_equipment_unit(
        &state.pool,
        &payload.equipment_ids,
        payload.unit_id,
    )
    .await?;

    let mut unit_ids = before_unit_ids;
    if let Some(unit_id) = payload.unit_id {
        unit_ids.push(unit_id);
    }
    notify_units(&state, unit_ids).await;

    Ok(Json(serde_json::json!({
        "ok_msg": "Equipment unit updated successfully",
        "updated_count": updated_count
    })))
}

pub async fn delete_equipment(
    State(state): State<AppState>,
    Path(equipment_id): Path<Uuid>,
) -> Result<impl IntoResponse, ApiErr> {
    let unit_ids = crate::service::get_unit_ids_by_equipment_ids(&state.pool, &[equipment_id]).await?;
    let deleted = crate::service::delete_equipment(&state.pool, equipment_id).await?;
    if !deleted {
        return Err(ApiErr::NotFound("Equipment not found".to_string(), None));
    }

    notify_units(&state, unit_ids).await;

    Ok(StatusCode::NO_CONTENT)
}