//! 统计 Service — 健康数据统计

use sea_orm::{ColumnTrait, EntityTrait, FromQueryResult, PaginatorTrait, QueryFilter, sea_query::Expr};

use erp_core::error::AppResult;

use crate::dto::stats_dto::*;
use crate::entity::{
    patient, lab_report, appointment, vital_signs,
};
use crate::state::HealthState;

// ---------------------------------------------------------------------------
// 健康数据统计
// ---------------------------------------------------------------------------

pub async fn get_lab_report_statistics(
    state: &HealthState,
    tenant_id: uuid::Uuid,
) -> AppResult<LabReportStatisticsResp> {
    let db = &state.db;

    let total_reports = lab_report::Entity::find()
        .filter(lab_report::Column::TenantId.eq(tenant_id))
        .filter(lab_report::Column::DeletedAt.is_null())
        .count(db)
        .await?;

    let this_month = lab_report::Entity::find()
        .filter(lab_report::Column::TenantId.eq(tenant_id))
        .filter(lab_report::Column::DeletedAt.is_null())
        .filter(Expr::col(lab_report::Column::CreatedAt).gte(Expr::cust("date_trunc('month', NOW())")))
        .count(db)
        .await?;

    let pending_review = lab_report::Entity::find()
        .filter(lab_report::Column::TenantId.eq(tenant_id))
        .filter(lab_report::Column::DeletedAt.is_null())
        .filter(lab_report::Column::Status.eq("pending"))
        .count(db)
        .await?;

    let reviewed = lab_report::Entity::find()
        .filter(lab_report::Column::TenantId.eq(tenant_id))
        .filter(lab_report::Column::DeletedAt.is_null())
        .filter(lab_report::Column::Status.eq("reviewed"))
        .count(db)
        .await?;

    let type_distribution = count_by_field(
        db, tenant_id,
        "SELECT report_type AS name, COUNT(*) AS value FROM lab_report \
         WHERE tenant_id = $1 AND deleted_at IS NULL \
         AND created_at >= date_trunc('month', NOW()) \
         GROUP BY report_type ORDER BY value DESC",
    ).await?;

    let abnormal_items = count_abnormal_lab_items(db, tenant_id).await?;

    Ok(LabReportStatisticsResp {
        total_reports: total_reports as i64,
        this_month: this_month as i64,
        type_distribution,
        abnormal_items,
        pending_review: pending_review as i64,
        reviewed: reviewed as i64,
    })
}

pub async fn get_appointment_statistics(
    state: &HealthState,
    tenant_id: uuid::Uuid,
) -> AppResult<AppointmentStatisticsResp> {
    let db = &state.db;

    let total_appointments = appointment::Entity::find()
        .filter(appointment::Column::TenantId.eq(tenant_id))
        .filter(appointment::Column::DeletedAt.is_null())
        .count(db)
        .await?;

    let this_month = appointment::Entity::find()
        .filter(appointment::Column::TenantId.eq(tenant_id))
        .filter(appointment::Column::DeletedAt.is_null())
        .filter(Expr::col(appointment::Column::CreatedAt).gte(Expr::cust("date_trunc('month', NOW())")))
        .count(db)
        .await?;

    let status_distribution = count_by_field(
        db, tenant_id,
        "SELECT status AS name, COUNT(*) AS value FROM appointment \
         WHERE tenant_id = $1 AND deleted_at IS NULL \
         AND created_at >= date_trunc('month', NOW()) \
         GROUP BY status ORDER BY value DESC",
    ).await?;

    let type_distribution = count_by_field(
        db, tenant_id,
        "SELECT appointment_type AS name, COUNT(*) AS value FROM appointment \
         WHERE tenant_id = $1 AND deleted_at IS NULL \
         AND created_at >= date_trunc('month', NOW()) \
         GROUP BY appointment_type ORDER BY value DESC",
    ).await?;

    let cancelled = appointment::Entity::find()
        .filter(appointment::Column::TenantId.eq(tenant_id))
        .filter(appointment::Column::DeletedAt.is_null())
        .filter(Expr::col(appointment::Column::CreatedAt).gte(Expr::cust("date_trunc('month', NOW())")))
        .filter(appointment::Column::Status.eq("cancelled"))
        .count(db)
        .await?;

    let cancel_rate = if this_month > 0 {
        (cancelled as f64 / this_month as f64) * 100.0
    } else {
        0.0
    };

    Ok(AppointmentStatisticsResp {
        total_appointments: total_appointments as i64,
        this_month: this_month as i64,
        status_distribution,
        type_distribution,
        cancel_rate,
    })
}

pub async fn get_vital_signs_report_rate(
    state: &HealthState,
    tenant_id: uuid::Uuid,
) -> AppResult<VitalSignsReportRateResp> {
    let db = &state.db;

    let total_patients = patient::Entity::find()
        .filter(patient::Column::TenantId.eq(tenant_id))
        .filter(patient::Column::DeletedAt.is_null())
        .count(db)
        .await?;

    let total_records = vital_signs::Entity::find()
        .filter(vital_signs::Column::TenantId.eq(tenant_id))
        .filter(vital_signs::Column::DeletedAt.is_null())
        .filter(Expr::col(vital_signs::Column::CreatedAt).gte(Expr::cust("date_trunc('month', NOW())")))
        .count(db)
        .await?;

    let reported_patients = count_distinct_patients_vital_signs(db, tenant_id).await?;

    let report_rate = if total_patients > 0 {
        (reported_patients as f64 / total_patients as f64) * 100.0
    } else {
        0.0
    };

    let daily_trend = compute_daily_report_rate(db, tenant_id).await?;

    Ok(VitalSignsReportRateResp {
        total_patients: total_patients as i64,
        reported_patients: reported_patients as i64,
        report_rate,
        total_records: total_records as i64,
        daily_trend,
    })
}

pub async fn get_health_data_stats(
    state: &HealthState,
    tenant_id: uuid::Uuid,
) -> AppResult<HealthDataStatsResp> {
    let lab_reports = get_lab_report_statistics(state, tenant_id).await?;
    let appointments = get_appointment_statistics(state, tenant_id).await?;
    let vital_signs_report_rate = get_vital_signs_report_rate(state, tenant_id).await?;

    Ok(HealthDataStatsResp {
        lab_reports,
        appointments,
        vital_signs_report_rate,
    })
}

// ---------------------------------------------------------------------------
// 辅助查询
// ---------------------------------------------------------------------------

#[derive(Debug, FromQueryResult)]
struct NameValueRow {
    name: String,
    value: i64,
}

async fn count_by_field(
    db: &sea_orm::DatabaseConnection,
    tenant_id: uuid::Uuid,
    sql: &str,
) -> AppResult<Vec<NameValue>> {
    let rows: Vec<NameValueRow> = sea_orm::FromQueryResult::find_by_statement(
        sea_orm::Statement::from_sql_and_values(
            sea_orm::DatabaseBackend::Postgres,
            sql,
            [tenant_id.into()],
        ),
    )
    .all(db)
    .await?;

    Ok(rows.into_iter().map(|r| NameValue { name: r.name, value: r.value }).collect())
}

async fn count_abnormal_lab_items(
    db: &sea_orm::DatabaseConnection,
    tenant_id: uuid::Uuid,
) -> AppResult<i64> {
    let sql = r#"
        SELECT COALESCE(SUM(jsonb_array_length(
            COALESCE(
                (SELECT jsonb_agg(elem) FROM jsonb_array_elements(CASE WHEN jsonb_typeof(items) = 'array' THEN items ELSE '[]'::jsonb END) elem WHERE elem->>'is_abnormal' = 'true'),
                '[]'::jsonb
            )
        )), 0::bigint) AS total
        FROM lab_report
        WHERE tenant_id = $1 AND deleted_at IS NULL AND items IS NOT NULL
          AND created_at >= date_trunc('month', NOW())
    "#;

    #[derive(Debug, FromQueryResult)]
    struct AbnormalCount {
        total: Option<i64>,
    }

    let result: Option<AbnormalCount> = sea_orm::FromQueryResult::find_by_statement(
        sea_orm::Statement::from_sql_and_values(
            sea_orm::DatabaseBackend::Postgres,
            sql,
            [tenant_id.into()],
        ),
    )
    .one(db)
    .await?;

    Ok(result.and_then(|r| r.total).unwrap_or(0))
}

async fn count_distinct_patients_vital_signs(
    db: &sea_orm::DatabaseConnection,
    tenant_id: uuid::Uuid,
) -> AppResult<u64> {
    let sql = r#"
        SELECT COUNT(DISTINCT patient_id) AS cnt
        FROM vital_signs
        WHERE tenant_id = $1 AND deleted_at IS NULL
          AND created_at >= date_trunc('month', NOW())
    "#;

    #[derive(Debug, FromQueryResult)]
    struct DistinctCount {
        cnt: i64,
    }

    let result: Option<DistinctCount> = sea_orm::FromQueryResult::find_by_statement(
        sea_orm::Statement::from_sql_and_values(
            sea_orm::DatabaseBackend::Postgres,
            sql,
            [tenant_id.into()],
        ),
    )
    .one(db)
    .await?;

    Ok(result.map(|r| r.cnt as u64).unwrap_or(0))
}

async fn compute_daily_report_rate(
    db: &sea_orm::DatabaseConnection,
    tenant_id: uuid::Uuid,
) -> AppResult<Vec<DailyReportRate>> {
    let sql = r#"
        SELECT d::date::text AS date,
               COUNT(DISTINCT vs.patient_id) AS reported,
               0::bigint AS total
        FROM generate_series(
            CURRENT_DATE - INTERVAL '6 days',
            CURRENT_DATE,
            INTERVAL '1 day'
        ) d
        LEFT JOIN vital_signs vs ON vs.record_date = d::date
            AND vs.tenant_id = $1 AND vs.deleted_at IS NULL
        GROUP BY d::date
        ORDER BY d::date
    "#;

    #[derive(Debug, FromQueryResult)]
    struct DailyRow {
        date: String,
        reported: i64,
        #[allow(dead_code)] // FromQueryResult 映射需要 total 字段，当前未读取
        total: i64,
    }

    let rows: Vec<DailyRow> = sea_orm::FromQueryResult::find_by_statement(
        sea_orm::Statement::from_sql_and_values(
            sea_orm::DatabaseBackend::Postgres,
            sql,
            [tenant_id.into()],
        ),
    )
    .all(db)
    .await?;

    let total_patients = patient::Entity::find()
        .filter(patient::Column::TenantId.eq(tenant_id))
        .filter(patient::Column::DeletedAt.is_null())
        .count(db)
        .await?;

    Ok(rows.into_iter().map(|r| {
        let total = total_patients as i64;
        let rate = if total > 0 { (r.reported as f64 / total as f64) * 100.0 } else { 0.0 };
        DailyReportRate { date: r.date, reported: r.reported, total, rate }
    }).collect())
}