//! Bütçe ve özet uç noktaları:
//!
//! | Yöntem | Yol | İş |
//! |---|---|---|
//! | GET | `/api/periods/{id}/summary`                     | gelir/gider/birikim/devir → harcanabilir, harcanan, kalan |
//! | GET | `/api/periods/{id}/budget`                      | 4 grup: aylık + haftalık döküm, her birinde harcanan |
//! | PUT | `/api/periods/{id}/budget`                      | 4 grubun aylık tutarları |
//! | PUT | `/api/periods/{id}/budget/weeks`                | bir haftayı elle ayarla / otomatiğe döndür |
//! | GET | `/api/periods/{id}/budget/suggestion?method=…` | `default` · `previous` · `avg3` |

use axum::{
    Json,
    extract::{Path, Query, State},
};
use mongodb::bson::Uuid;
use serde::{Deserialize, Serialize};
use ts_rs::TS;
use validator::Validate;

use crate::{
    auth::AuthUser,
    error::{AppError, AppResult},
    extract::ValidJson,
    models::group::Group,
    services::budget::{self, GroupBudget, SuggestMethod},
    state::AppState,
};

/// Gruplara göre tutarlar (kuruş)
#[derive(Serialize, Deserialize, Validate, TS, Clone, Copy)]
#[ts(export)]
pub struct GroupAmounts {
    #[ts(type = "number")]
    needs: i64,
    #[ts(type = "number")]
    wants: i64,
    #[ts(type = "number")]
    culture: i64,
    #[ts(type = "number")]
    unexpected: i64,
}

impl From<budget::GroupAmounts> for GroupAmounts {
    fn from(a: budget::GroupAmounts) -> Self {
        Self {
            needs: a[0],
            wants: a[1],
            culture: a[2],
            unexpected: a[3],
        }
    }
}

impl From<GroupAmounts> for budget::GroupAmounts {
    fn from(a: GroupAmounts) -> Self {
        [a.needs, a.wants, a.culture, a.unexpected]
    }
}

#[derive(Serialize, TS)]
#[ts(export, rename = "PeriodSummary")]
pub struct SummaryDto {
    #[ts(type = "number")]
    income_total: i64,
    #[ts(type = "number")]
    fixed_expense_total: i64,
    #[ts(type = "number")]
    savings_goal: i64,
    /// Önceki dönemden devreden borç
    #[ts(type = "number")]
    carryover_debt: i64,
    /// Önceki dönemden devreden artı bakiye
    #[ts(type = "number")]
    carryover_surplus: i64,
    /// gelir − sabit gider − birikim − borç + artı
    #[ts(type = "number")]
    spendable: i64,
    /// 4 grubun aylık bütçe toplamı
    #[ts(type = "number")]
    budget_total: i64,
    /// harcanabilir − dağıtılan (negatifse fazla dağıtılmış)
    #[ts(type = "number")]
    unallocated: i64,
    /// Dönemde gerçekleşen harcama
    #[ts(type = "number")]
    spent_total: i64,
    /// Kalan harcanabilir: harcanabilir − gerçekleşen (negatifse aşılmış)
    #[ts(type = "number")]
    remaining: i64,
}

#[derive(Serialize, TS)]
#[ts(export, rename = "GroupBudget")]
pub struct GroupBudgetDto {
    group: Group,
    #[ts(type = "number")]
    monthly: i64,
    /// Dönem boyunca gerçekleşen harcama
    #[ts(type = "number")]
    spent: i64,
    /// Elle girilen haftaların toplamı aylık tutarı aşıyor
    weekly_over: bool,
    weeks: Vec<WeekBudgetDto>,
}

#[derive(Serialize, TS)]
#[ts(export, rename = "WeekBudget")]
struct WeekBudgetDto {
    index: u32,
    start_date: String,
    last_date: String,
    days: u32,
    #[ts(type = "number")]
    amount: i64,
    /// Elle girildi (otomatik değil)
    is_manual: bool,
    /// Bu haftada gerçekleşen harcama
    #[ts(type = "number")]
    spent: i64,
}

impl From<GroupBudget> for GroupBudgetDto {
    fn from(g: GroupBudget) -> Self {
        Self {
            group: g.group,
            monthly: g.monthly,
            spent: g.spent,
            weekly_over: g.weekly_over,
            weeks: g
                .weeks
                .into_iter()
                .map(|w| WeekBudgetDto {
                    index: w.index,
                    start_date: w.start_date,
                    last_date: w.last_date,
                    days: w.days,
                    amount: w.amount,
                    is_manual: w.is_manual,
                    spent: w.spent,
                })
                .collect(),
        }
    }
}

#[derive(Deserialize, Validate, TS)]
#[ts(export, rename = "BudgetWeekRequest")]
pub struct WeekRequest {
    group: Group,
    /// Haftanın ilk günü (`PeriodWeek.start_date`)
    week_start: String,
    /// Kuruş; `null` → otomatiğe döndür
    #[ts(type = "number | null")]
    amount: Option<i64>,
}

#[derive(Deserialize, Clone, Copy, TS)]
#[serde(rename_all = "lowercase")]
#[ts(export, rename = "SuggestMethod")]
pub enum Method {
    Default,
    Previous,
    Avg3,
}

#[derive(Deserialize)]
pub struct SuggestQuery {
    method: Option<Method>,
}

#[derive(Serialize, TS)]
#[ts(export, rename = "BudgetSuggestion")]
pub struct SuggestionDto {
    /// `false` → bu yöntem için veri yok (`message` nedenini söyler)
    available: bool,
    message: Option<String>,
    amounts: GroupAmounts,
}

fn parse_id(id: &str) -> AppResult<Uuid> {
    Uuid::parse_str(id).map_err(|_| AppError::NotFound)
}

pub async fn summary(
    State(s): State<AppState>,
    auth: AuthUser,
    Path(id): Path<String>,
) -> AppResult<Json<SummaryDto>> {
    let x = budget::summary(&s.db, auth.household_id, parse_id(&id)?).await?;
    Ok(Json(SummaryDto {
        income_total: x.income_total,
        fixed_expense_total: x.fixed_expense_total,
        savings_goal: x.savings_goal,
        carryover_debt: x.carryover_debt,
        carryover_surplus: x.carryover_surplus,
        spendable: x.spendable,
        budget_total: x.budget_total,
        unallocated: x.spendable - x.budget_total,
        spent_total: x.spent_total,
        remaining: x.spendable - x.spent_total,
    }))
}

pub async fn get(
    State(s): State<AppState>,
    auth: AuthUser,
    Path(id): Path<String>,
) -> AppResult<Json<Vec<GroupBudgetDto>>> {
    let groups = budget::view(&s.db, auth.household_id, parse_id(&id)?).await?;
    Ok(Json(groups.into_iter().map(GroupBudgetDto::from).collect()))
}

pub async fn set_monthly(
    State(s): State<AppState>,
    auth: AuthUser,
    Path(id): Path<String>,
    ValidJson(req): ValidJson<GroupAmounts>,
) -> AppResult<Json<Vec<GroupBudgetDto>>> {
    let pid = parse_id(&id)?;
    budget::set_monthly(&s.db, auth.household_id, pid, req.into()).await?;
    let groups = budget::view(&s.db, auth.household_id, pid).await?;
    Ok(Json(groups.into_iter().map(GroupBudgetDto::from).collect()))
}

pub async fn set_week(
    State(s): State<AppState>,
    auth: AuthUser,
    Path(id): Path<String>,
    ValidJson(req): ValidJson<WeekRequest>,
) -> AppResult<Json<Vec<GroupBudgetDto>>> {
    let pid = parse_id(&id)?;
    budget::set_week(
        &s.db,
        auth.household_id,
        pid,
        req.group,
        &req.week_start,
        req.amount,
    )
    .await?;
    let groups = budget::view(&s.db, auth.household_id, pid).await?;
    Ok(Json(groups.into_iter().map(GroupBudgetDto::from).collect()))
}

pub async fn suggestion(
    State(s): State<AppState>,
    auth: AuthUser,
    Path(id): Path<String>,
    Query(q): Query<SuggestQuery>,
) -> AppResult<Json<SuggestionDto>> {
    let method = match q.method.unwrap_or(Method::Default) {
        Method::Default => SuggestMethod::Default,
        Method::Previous => SuggestMethod::Previous,
        Method::Avg3 => SuggestMethod::Avg3,
    };
    let x = budget::suggest(&s.db, auth.household_id, parse_id(&id)?, method).await?;
    Ok(Json(SuggestionDto {
        available: x.available,
        message: x.message,
        amounts: x.amounts.into(),
    }))
}