//! JSON tam hane yedeği (`services::backup`).
//!
//! | Yöntem | Yol | Kim | İş |
//! |---|---|---|---|
//! | GET  | `/api/backup/download`                     | üye  | yedek dosyası (indirme) |
//! | GET  | `/api/backup/status`                       | üye  | son yedek zamanı + geri dönüş noktaları (yalnız sahip görür) |
//! | POST | `/api/backup/preview`                      | sahip | gövde: yedek dosyası → ne değişecek (hiçbir şey yazılmaz) |
//! | POST | `/api/backup/restore`                      | sahip | gövde: yedek dosyası → hane verisi değiştirilir |
//! | POST | `/api/backup/restore-points/{id}/restore`  | sahip | geri dönüş noktasına dön ("geri al") |

use axum::{
    Json,
    body::Bytes,
    extract::{Path, State},
    http::header,
    response::IntoResponse,
};
use mongodb::bson::DateTime;
use serde::Serialize;
use ts_rs::TS;

use crate::{
    auth::AuthUser,
    error::{AppError, AppResult},
    models::user::Role,
    services::{
        backup::{self, Reason},
        calendar::{format_date, today_tr},
    },
    state::AppState,
};

fn iso(d: DateTime) -> String {
    d.try_to_rfc3339_string().unwrap_or_default()
}

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

pub async fn download(State(s): State<AppState>, auth: AuthUser) -> AppResult<impl IntoResponse> {
    let snap = backup::collect(&s.db, auth.household_id).await?;
    let body = backup::to_json(&snap)?;
    backup::mark_exported(&s.db, auth.household_id).await?;
    let file = format!(
        "kakeibo-yedek-{}-{}.json",
        backup::slug(&snap.household_name),
        format_date(today_tr())
    );
    Ok((
        [
            (
                header::CONTENT_TYPE,
                "application/json; charset=utf-8".to_string(),
            ),
            (
                header::CONTENT_DISPOSITION,
                format!("attachment; filename=\"{file}\""),
            ),
            (header::CACHE_CONTROL, "no-store".to_string()),
        ],
        body,
    ))
}

#[derive(Serialize, TS)]
#[ts(export)]
pub struct RestorePoint {
    id: String,
    /// RFC 3339
    created_at: String,
    /// `before_restore`: dosyadan geri yüklemeden önce · `before_undo`: geri almadan önce
    #[ts(type = "\"before_restore\" | \"before_undo\"")]
    reason: String,
    #[ts(type = "number")]
    periods: i64,
    #[ts(type = "number")]
    entries: i64,
    /// Sıkıştırılmış boyut (bayt)
    #[ts(type = "number")]
    size: i64,
}

#[derive(Serialize, TS)]
#[ts(export)]
pub struct BackupStatus {
    /// Son dışa aktarma (RFC 3339); hiç alınmadıysa `null`
    last_backup_at: Option<String>,
    /// En yeniden eskiye; sahip olmayana boş
    restore_points: Vec<RestorePoint>,
    keep_points: u32,
    keep_days: u32,
}

pub async fn status(State(s): State<AppState>, auth: AuthUser) -> AppResult<Json<BackupStatus>> {
    let points = if auth.role == Role::Owner {
        backup::points(&s.db, auth.household_id).await?
    } else {
        Vec::new()
    };
    Ok(Json(BackupStatus {
        last_backup_at: backup::last_exported(&s.db, auth.household_id)
            .await?
            .map(iso),
        restore_points: points
            .into_iter()
            .map(|p| RestorePoint {
                id: p.id.to_string(),
                created_at: iso(p.created_at),
                reason: p.reason,
                periods: p.periods,
                entries: p.entries,
                size: p.size,
            })
            .collect(),
        keep_points: backup::KEEP_POINTS as u32,
        keep_days: backup::KEEP_DAYS as u32,
    }))
}

#[derive(Serialize, TS)]
#[ts(export)]
pub struct BackupCount {
    /// Koleksiyon adı (`entries`, `periods`, …)
    kind: String,
    /// Türkçe ad
    label: String,
    #[ts(type = "number")]
    backup: i64,
    #[ts(type = "number")]
    current: i64,
}

#[derive(Serialize, TS)]
#[ts(export)]
pub struct BackupPreview {
    source_name: String,
    same_household: bool,
    /// RFC 3339
    exported_at: String,
    app_version: String,
    counts: Vec<BackupCount>,
    /// Yedekteki dönemlerin ilk ve son günü
    first_date: Option<String>,
    last_date: Option<String>,
    /// Aynı hane: yedekten sonra eklenen/değişen (kaybolacak) kayıt
    #[ts(type = "number")]
    changed_since: i64,
    warnings: Vec<String>,
}

pub async fn preview(
    State(s): State<AppState>,
    auth: AuthUser,
    body: Bytes,
) -> AppResult<Json<BackupPreview>> {
    auth.require_owner()?;
    let snap = backup::parse(&body)?;
    let p = backup::preview(&s.db, auth.household_id, &snap).await?;
    Ok(Json(BackupPreview {
        source_name: p.source_name,
        same_household: p.same_household,
        exported_at: iso(p.exported_at),
        app_version: p.app_version,
        counts: p
            .counts
            .into_iter()
            .map(|c| BackupCount {
                kind: c.kind.into(),
                label: c.label.into(),
                backup: c.backup,
                current: c.current,
            })
            .collect(),
        first_date: p.first_date,
        last_date: p.last_date,
        changed_since: p.changed_since,
        warnings: p.warnings,
    }))
}

#[derive(Serialize, TS)]
#[ts(export)]
pub struct RestoreResult {
    /// İşlemden önceki durumun geri dönüş noktası ("Geri al" bununla)
    restore_point_id: String,
}

pub async fn restore(
    State(s): State<AppState>,
    auth: AuthUser,
    body: Bytes,
) -> AppResult<Json<RestoreResult>> {
    auth.require_owner()?;
    let snap = backup::parse(&body)?;
    let id = backup::restore(
        &s.db,
        auth.household_id,
        auth.user_id,
        &snap,
        Reason::BeforeRestore,
    )
    .await?;
    Ok(Json(RestoreResult {
        restore_point_id: id.to_string(),
    }))
}

pub async fn undo(
    State(s): State<AppState>,
    auth: AuthUser,
    Path(id): Path<String>,
) -> AppResult<Json<RestoreResult>> {
    auth.require_owner()?;
    let id = backup::undo(&s.db, auth.household_id, auth.user_id, parse_id(&id)?).await?;
    Ok(Json(RestoreResult {
        restore_point_id: id.to_string(),
    }))
}