use crate::AppService;
use crate::error::AppError;
use chrono::{DateTime, Utc};
use models::ai::billing_error;
use models::projects::project_billing_history;
use models::users::user_billing;
use sea_orm::sea_query::prelude::rust_decimal::prelude::ToPrimitive;
use sea_orm::*;
use serde::{Deserialize, Serialize};
use session::Session;
use utoipa::{IntoParams, ToSchema};
use uuid::Uuid;

#[derive(Debug, Clone, Serialize, Deserialize, ToSchema)]
pub struct UserBillingResponse {
    pub user_uid: Uuid,
    pub balance: f64,
    pub currency: String,
    pub is_pro: bool,
    pub monthly_quota: f64,
    pub month_used: f64,
    pub cycle_start_utc: Option<DateTime<Utc>>,
    pub cycle_end_utc: Option<DateTime<Utc>>,
    pub updated_at: DateTime<Utc>,
    pub created_at: DateTime<Utc>,
}

#[derive(Debug, Clone, Serialize, Deserialize, ToSchema)]
pub struct UserBillingErrorsResponse {
    pub list: Vec<UserBillingErrorItem>,
}

#[derive(Debug, Clone, Serialize, Deserialize, ToSchema)]
pub struct UserBillingErrorItem {
    pub id: Uuid,
    pub scope: String,
    pub scope_id: Uuid,
    pub error_type: String,
    pub message: String,
    pub details: Option<serde_json::Value>,
    pub resolved: bool,
    pub created_at: DateTime<Utc>,
}

#[derive(Debug, Clone, Serialize, Deserialize, ToSchema, IntoParams)]
pub struct UserBillingHistoryQuery {
    pub page: Option<u64>,
    pub per_page: Option<u64>,
}

#[derive(Debug, Clone, Serialize, Deserialize, ToSchema)]
pub struct UserBillingHistoryItem {
    pub uid: Uuid,
    pub project_uid: Uuid,
    pub user_uid: Option<Uuid>,
    pub amount: f64,
    pub currency: String,
    pub reason: String,
    pub extra: Option<serde_json::Value>,
    pub created_at: DateTime<Utc>,
}

#[derive(Debug, Clone, Serialize, Deserialize, ToSchema)]
pub struct UserBillingHistoryResponse {
    pub page: u64,
    pub per_page: u64,
    pub total: u64,
    pub list: Vec<UserBillingHistoryItem>,
}

impl AppService {
    pub async fn user_billing_current(
        &self,
        ctx: &Session,
    ) -> Result<UserBillingResponse, AppError> {
        let user_uid = ctx.user().ok_or(AppError::Unauthorized)?;

        let billing = match user_billing::Entity::find_by_id(user_uid)
            .one(&self.db)
            .await?
        {
            Some(b) => b,
            None => {
                let now = Utc::now();
                let active = user_billing::ActiveModel {
                    user: Set(user_uid),
                    balance: Set(rust_decimal::Decimal::from(10)),
                    currency: Set("USD".to_string()),
                    is_pro: Set(false),
                    monthly_quota: Set(rust_decimal::Decimal::from(0)),
                    month_used: Set(rust_decimal::Decimal::from(0)),
                    cycle_start: Set(None),
                    cycle_end: Set(None),
                    updated_at: Set(now),
                    created_at: Set(now),
                };
                active.insert(&self.db).await?
            }
        };

        Ok(UserBillingResponse {
            user_uid: billing.user,
            balance: billing.balance.to_f64().unwrap_or_default(),
            currency: billing.currency,
            is_pro: billing.is_pro,
            monthly_quota: billing.monthly_quota.to_f64().unwrap_or_default(),
            month_used: billing.month_used.to_f64().unwrap_or_default(),
            cycle_start_utc: billing.cycle_start,
            cycle_end_utc: billing.cycle_end,
            updated_at: billing.updated_at,
            created_at: billing.created_at,
        })
    }

    pub async fn user_billing_errors(
        &self,
        ctx: &Session,
    ) -> Result<UserBillingErrorsResponse, AppError> {
        let user_uid = ctx.user().ok_or(AppError::Unauthorized)?;

        let errors = billing_error::Entity::find()
            .filter(billing_error::Column::Scope.eq("user"))
            .filter(billing_error::Column::ScopeId.eq(user_uid))
            .filter(billing_error::Column::Resolved.eq(false))
            .order_by_desc(billing_error::Column::CreatedAt)
            .all(&self.db)
            .await?;

        Ok(UserBillingErrorsResponse {
            list: errors
                .into_iter()
                .map(|e| UserBillingErrorItem {
                    id: e.id,
                    scope: e.scope,
                    scope_id: e.scope_id,
                    error_type: e.error_type,
                    message: e.message,
                    details: e.details,
                    resolved: e.resolved,
                    created_at: e.created_at,
                })
                .collect(),
        })
    }

    pub async fn user_billing_history(
        &self,
        ctx: &Session,
        query: UserBillingHistoryQuery,
    ) -> Result<UserBillingHistoryResponse, AppError> {
        let user_uid = ctx.user().ok_or(AppError::Unauthorized)?;
        let page = std::cmp::max(query.page.unwrap_or(1), 1);
        let per_page = query.per_page.unwrap_or(20).clamp(1, 200);

        let paginator = project_billing_history::Entity::find()
            .filter(project_billing_history::Column::User.eq(user_uid))
            .order_by_desc(project_billing_history::Column::CreatedAt)
            .paginate(&self.db, per_page);
        let total = paginator.num_items().await?;
        let rows = paginator.fetch_page(page - 1).await?;

        let list = rows
            .into_iter()
            .map(|x| UserBillingHistoryItem {
                uid: x.uid,
                project_uid: x.project,
                user_uid: x.user,
                amount: x.amount.to_f64().unwrap_or_default(),
                currency: x.currency,
                reason: x.reason,
                extra: x.extra.map(|v| v.into()),
                created_at: x.created_at,
            })
            .collect();

        Ok(UserBillingHistoryResponse {
            page,
            per_page,
            total,
            list,
        })
    }
}