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

use crate::{
    control::validator::{validate_manual_control, ControlAction},
    util::{
        pagination::{PaginatedResponse, PaginationParams},
        response::ApiErr,
    },
    AppState,
};

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

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

    let total = crate::service::get_units_count(&state.pool, query.keyword.as_deref()).await?;
    let data = crate::service::get_units_paginated(
        &state.pool,
        query.keyword.as_deref(),
        query.pagination.page_size,
        query.pagination.offset(),
    )
    .await?;

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

pub async fn start_equipment(
    State(state): State<AppState>,
    Path(equipment_id): Path<Uuid>,
) -> Result<impl IntoResponse, ApiErr> {
    send_equipment_command(state, equipment_id, ControlAction::Start).await
}

pub async fn stop_equipment(
    State(state): State<AppState>,
    Path(equipment_id): Path<Uuid>,
) -> Result<impl IntoResponse, ApiErr> {
    send_equipment_command(state, equipment_id, ControlAction::Stop).await
}


async fn send_equipment_command(
    state: AppState,
    equipment_id: Uuid,
    action: ControlAction,
) -> Result<impl IntoResponse, ApiErr> {
    let context = validate_manual_control(&state, equipment_id, action).await?;
    let pulse_ms = 300u64;

    crate::control::command::send_pulse_command(
        &state.connection_manager,
        context.command_point.point_id,
        context.command_value_type.as_ref(),
        pulse_ms,
    )
    .await
    .map_err(|e| ApiErr::Internal(e, None))?;

    if state.config.simulate_plc {
        crate::control::command::simulate_run_feedback(
            &state,
            equipment_id,
            matches!(action, ControlAction::Start),
        )
        .await;
    }

    let event = match action {
        ControlAction::Start => crate::event::AppEvent::EquipmentStartCommandSent {
            equipment_id,
            unit_id: context.unit_id,
            point_id: context.command_point.point_id,
        },
        ControlAction::Stop => crate::event::AppEvent::EquipmentStopCommandSent {
            equipment_id,
            unit_id: context.unit_id,
            point_id: context.command_point.point_id,
        },
    };
    let _ = state.event_manager.send(event);

    Ok(Json(json!({
        "ok_msg": format!("Equipment {} command sent", action.as_str()),
        "equipment_id": equipment_id,
        "unit_id": context.unit_id,
        "command_role": context.command_point.signal_role,
        "command_point_id": context.command_point.point_id,
        "pulse_ms": pulse_ms
    })))
}

pub async fn get_unit(
    State(state): State<AppState>,
    Path(unit_id): Path<Uuid>,
) -> Result<impl IntoResponse, ApiErr> {
    match crate::service::get_unit_by_id(&state.pool, unit_id).await? {
        Some(unit) => Ok(Json(unit)),
        None => Err(ApiErr::NotFound("Unit not found".to_string(), None)),
    }
}

#[derive(serde::Serialize)]
pub struct PointDetail {
    #[serde(flatten)]
    pub point: crate::model::Point,
    pub point_monitor: Option<crate::telemetry::PointMonitorInfo>,
}

#[derive(serde::Serialize)]
pub struct EquipmentDetail {
    #[serde(flatten)]
    pub equipment: crate::model::Equipment,
    pub points: Vec<PointDetail>,
}

#[derive(serde::Serialize)]
pub struct UnitDetail {
    #[serde(flatten)]
    pub unit: crate::model::ControlUnit,
    pub equipments: Vec<EquipmentDetail>,
}

pub async fn get_unit_detail(
    State(state): State<AppState>,
    Path(unit_id): Path<Uuid>,
) -> Result<impl IntoResponse, ApiErr> {
    let unit = crate::service::get_unit_by_id(&state.pool, unit_id)
        .await?
        .ok_or_else(|| ApiErr::NotFound("Unit not found".to_string(), None))?;

    let equipments = crate::service::get_equipment_by_unit_id(&state.pool, unit_id).await?;
    let equipment_ids: Vec<Uuid> = equipments.iter().map(|e| e.id).collect();
    let all_points = crate::service::get_points_by_equipment_ids(&state.pool, &equipment_ids).await?;

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

    let equipments = equipments
        .into_iter()
        .map(|eq| {
            let points = all_points
                .iter()
                .filter(|p| p.equipment_id == Some(eq.id))
                .map(|p| PointDetail {
                    point_monitor: monitor_guard.get(&p.id).cloned(),
                    point: p.clone(),
                })
                .collect();
            EquipmentDetail { equipment: eq, points }
        })
        .collect();

    Ok(Json(UnitDetail { unit, equipments }))
}

#[derive(Debug, Deserialize, Validate)]
pub struct CreateUnitReq {
    #[validate(length(min = 1, max = 100))]
    pub code: String,
    #[validate(length(min = 1, max = 100))]
    pub name: String,
    pub description: Option<String>,
    pub enabled: Option<bool>,
    #[validate(range(min = 0))]
    pub run_time_sec: Option<i32>,
    #[validate(range(min = 0))]
    pub stop_time_sec: Option<i32>,
    #[validate(range(min = 0))]
    pub acc_time_sec: Option<i32>,
    #[validate(range(min = 0))]
    pub bl_time_sec: Option<i32>,
    pub require_manual_ack_after_fault: Option<bool>,
}

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

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

    let unit_id = crate::service::create_unit(
        &state.pool,
        crate::service::CreateUnitParams {
            code: &payload.code,
            name: &payload.name,
            description: payload.description.as_deref(),
            enabled: payload.enabled.unwrap_or(true),
            run_time_sec: payload.run_time_sec.unwrap_or(0),
            stop_time_sec: payload.stop_time_sec.unwrap_or(0),
            acc_time_sec: payload.acc_time_sec.unwrap_or(0),
            bl_time_sec: payload.bl_time_sec.unwrap_or(0),
            require_manual_ack_after_fault: payload
                .require_manual_ack_after_fault
                .unwrap_or(true),
        },
    )
    .await?;

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

#[derive(Debug, Deserialize, Validate)]
pub struct UpdateUnitReq {
    #[validate(length(min = 1, max = 100))]
    pub code: Option<String>,
    #[validate(length(min = 1, max = 100))]
    pub name: Option<String>,
    pub description: Option<String>,
    pub enabled: Option<bool>,
    #[validate(range(min = 0))]
    pub run_time_sec: Option<i32>,
    #[validate(range(min = 0))]
    pub stop_time_sec: Option<i32>,
    #[validate(range(min = 0))]
    pub acc_time_sec: Option<i32>,
    #[validate(range(min = 0))]
    pub bl_time_sec: Option<i32>,
    pub require_manual_ack_after_fault: Option<bool>,
}

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

    if crate::service::get_unit_by_id(&state.pool, unit_id)
        .await?
        .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_unit_by_code(&state.pool, code).await?;
        if duplicate.as_ref().is_some_and(|item| item.id != unit_id) {
            return Err(ApiErr::BadRequest(
                "Unit code already exists".to_string(),
                None,
            ));
        }
    }

    if payload.code.is_none()
        && payload.name.is_none()
        && payload.description.is_none()
        && payload.enabled.is_none()
        && payload.run_time_sec.is_none()
        && payload.stop_time_sec.is_none()
        && payload.acc_time_sec.is_none()
        && payload.bl_time_sec.is_none()
        && payload.require_manual_ack_after_fault.is_none()
    {
        return Ok(Json(serde_json::json!({"ok_msg": "No fields to update"})));
    }

    crate::service::update_unit(
        &state.pool,
        unit_id,
        crate::service::UpdateUnitParams {
            code: payload.code.as_deref(),
            name: payload.name.as_deref(),
            description: payload.description.as_deref(),
            enabled: payload.enabled,
            run_time_sec: payload.run_time_sec,
            stop_time_sec: payload.stop_time_sec,
            acc_time_sec: payload.acc_time_sec,
            bl_time_sec: payload.bl_time_sec,
            require_manual_ack_after_fault: payload.require_manual_ack_after_fault,
        },
    )
    .await?;

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

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

    Ok(StatusCode::NO_CONTENT)
}

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

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

    let total = crate::service::get_events_count(
        &state.pool,
        query.unit_id,
        query.event_type.as_deref(),
    )
    .await?;
    let data = crate::service::get_events_paginated(
        &state.pool,
        query.unit_id,
        query.event_type.as_deref(),
        query.pagination.page_size,
        query.pagination.offset(),
    )
    .await?;

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

pub async fn start_auto_unit(
    State(state): State<AppState>,
    Path(unit_id): Path<Uuid>,
) -> Result<impl IntoResponse, ApiErr> {
    let unit = crate::service::get_unit_by_id(&state.pool, unit_id)
        .await?
        .ok_or_else(|| ApiErr::NotFound("Unit not found".to_string(), None))?;

    if !unit.enabled {
        return Err(ApiErr::BadRequest("Unit is disabled".to_string(), None));
    }

    let mut runtime = state.control_runtime.get_or_init(unit_id).await;
    runtime.auto_enabled = true;
    runtime.state = crate::control::runtime::UnitRuntimeState::Stopped;
    runtime.current_stop_elapsed_sec = 0;
    state.control_runtime.upsert(runtime).await;

    let _ = state.event_manager.send(crate::event::AppEvent::AutoControlStarted { unit_id });

    Ok(Json(json!({ "ok_msg": "Auto control started", "unit_id": unit_id })))
}

pub async fn stop_auto_unit(
    State(state): State<AppState>,
    Path(unit_id): Path<Uuid>,
) -> Result<impl IntoResponse, ApiErr> {
    crate::service::get_unit_by_id(&state.pool, unit_id)
        .await?
        .ok_or_else(|| ApiErr::NotFound("Unit not found".to_string(), None))?;

    let mut runtime = state.control_runtime.get_or_init(unit_id).await;
    runtime.auto_enabled = false;
    state.control_runtime.upsert(runtime).await;

    let _ = state.event_manager.send(crate::event::AppEvent::AutoControlStopped { unit_id });

    Ok(Json(json!({ "ok_msg": "Auto control stopped", "unit_id": unit_id })))
}

pub async fn ack_fault_unit(
    State(state): State<AppState>,
    Path(unit_id): Path<Uuid>,
) -> Result<impl IntoResponse, ApiErr> {
    crate::service::get_unit_by_id(&state.pool, unit_id)
        .await?
        .ok_or_else(|| ApiErr::NotFound("Unit not found".to_string(), None))?;

    let mut runtime = state.control_runtime.get_or_init(unit_id).await;

    if !runtime.fault_locked {
        return Err(ApiErr::BadRequest(
            "Unit is not fault locked".to_string(),
            Some(json!({ "unit_id": unit_id })),
        ));
    }
    if runtime.flt_active {
        return Err(ApiErr::BadRequest(
            "FLT is still active, cannot acknowledge".to_string(),
            Some(json!({ "unit_id": unit_id })),
        ));
    }

    runtime.fault_locked = false;
    runtime.manual_ack_required = false;
    runtime.state = crate::control::runtime::UnitRuntimeState::Stopped;
    state.control_runtime.upsert(runtime).await;

    let _ = state.event_manager.send(crate::event::AppEvent::FaultAcked { unit_id });

    Ok(Json(json!({ "ok_msg": "Fault acknowledged", "unit_id": unit_id })))
}

pub async fn get_unit_runtime(
    State(state): State<AppState>,
    Path(unit_id): Path<Uuid>,
) -> Result<impl IntoResponse, ApiErr> {
    crate::service::get_unit_by_id(&state.pool, unit_id)
        .await?
        .ok_or_else(|| ApiErr::NotFound("Unit not found".to_string(), None))?;

    let runtime = state.control_runtime.get_or_init(unit_id).await;
    Ok(Json(runtime))
}