package repository

import (
	"context"
	"fmt"
	"time"

	"github.com/prabhupadasays/spsays-bff/internal/model"
)

// SadhnaRepo wraps Postgres access for sadhna_logs — the chanting half of
// a day's sādhana. The posting half lives in the posts table and is read
// via PostRepo.PostedDates, so this repo stays small.
type SadhnaRepo struct{ pg *Postgres }

func NewSadhnaRepo(pg *Postgres) *SadhnaRepo { return &SadhnaRepo{pg: pg} }

// UpsertToday records (or updates) the given day's chanting progress for
// the user. The caller passes the UTC calendar date explicitly (rather
// than relying on the DB's CURRENT_DATE) so day bucketing stays identical
// to PostedDates' `AT TIME ZONE 'UTC'`. chantDone is decided by the caller
// — rounds_completed >= the user's current target — and frozen into the
// row so later target changes don't rewrite past days. Returns the row.
func (r *SadhnaRepo) UpsertToday(ctx context.Context, userID string, logDate time.Time, rounds int, chantDone bool) (*model.SadhnaLog, error) {
	var l model.SadhnaLog
	err := r.pg.Pool.QueryRow(ctx, `
		INSERT INTO sadhna_logs (user_id, log_date, rounds_completed, chant_done)
		VALUES ($1, $2, $3, $4)
		ON CONFLICT (user_id, log_date) DO UPDATE
		    SET rounds_completed = EXCLUDED.rounds_completed,
		        chant_done       = EXCLUDED.chant_done,
		        updated_at       = now()
		RETURNING id, user_id, log_date, rounds_completed, chant_done, created_at, updated_at`,
		userID, logDate, rounds, chantDone,
	).Scan(&l.ID, &l.UserID, &l.LogDate, &l.RoundsCompleted, &l.ChantDone, &l.CreatedAt, &l.UpdatedAt)
	if err != nil {
		return nil, fmt.Errorf("upsert sadhna log: %w", err)
	}
	return &l, nil
}

// ListSince returns the user's sadhna logs on or after `since`, newest
// first. The window bounds the streak/growth computation; a few hundred
// rows at most.
func (r *SadhnaRepo) ListSince(ctx context.Context, userID string, since time.Time) ([]model.SadhnaLog, error) {
	rows, err := r.pg.Pool.Query(ctx, `
		SELECT id, user_id, log_date, rounds_completed, chant_done, created_at, updated_at
		FROM sadhna_logs
		WHERE user_id = $1 AND log_date >= $2
		ORDER BY log_date DESC`,
		userID, since,
	)
	if err != nil {
		return nil, fmt.Errorf("list sadhna logs: %w", err)
	}
	defer rows.Close()

	var out []model.SadhnaLog
	for rows.Next() {
		var l model.SadhnaLog
		if err := rows.Scan(&l.ID, &l.UserID, &l.LogDate, &l.RoundsCompleted, &l.ChantDone, &l.CreatedAt, &l.UpdatedAt); err != nil {
			return nil, fmt.Errorf("scan sadhna log: %w", err)
		}
		out = append(out, l)
	}
	return out, rows.Err()
}