package repository

import (
	"context"
	"errors"
	"time"

	"github.com/google/uuid"
	"github.com/jackc/pgx/v5"
	"github.com/jackc/pgx/v5/pgxpool"

	"github.com/yuxingu/digital-psychology/apps/api/internal/model"
)

// GrowthRepo persists growth plans and check-ins.
type GrowthRepo struct {
	Pool *pgxpool.Pool
}

// CreatePlan inserts a plan.
func (r *GrowthRepo) CreatePlan(ctx context.Context, userID uuid.UUID, title, focus string) (*model.GrowthPlan, error) {
	p := &model.GrowthPlan{}
	err := r.Pool.QueryRow(ctx, `
		INSERT INTO growth_plans(user_id, title, focus)
		VALUES ($1,$2,$3)
		RETURNING id, user_id, title, focus, status, created_at`,
		userID, title, focus,
	).Scan(&p.ID, &p.UserID, &p.Title, &p.Focus, &p.Status, &p.CreatedAt)
	return p, err
}

// ListPlans returns active plans for user.
func (r *GrowthRepo) ListPlans(ctx context.Context, userID uuid.UUID) ([]model.GrowthPlan, error) {
	rows, err := r.Pool.Query(ctx, `
		SELECT id, user_id, title, focus, status, created_at
		FROM growth_plans
		WHERE user_id=$1 AND deleted_at IS NULL AND status='active'
		ORDER BY created_at DESC LIMIT 20`, userID)
	if err != nil {
		return nil, err
	}
	defer rows.Close()
	var out []model.GrowthPlan
	for rows.Next() {
		var p model.GrowthPlan
		if err := rows.Scan(&p.ID, &p.UserID, &p.Title, &p.Focus, &p.Status, &p.CreatedAt); err != nil {
			return nil, err
		}
		out = append(out, p)
	}
	return out, rows.Err()
}

// Checkin upserts today's check-in.
func (r *GrowthRepo) Checkin(ctx context.Context, userID, planID uuid.UUID, day time.Time, note *string) (*model.GrowthCheckin, error) {
	var owner uuid.UUID
	err := r.Pool.QueryRow(ctx, `
		SELECT user_id FROM growth_plans WHERE id=$1 AND deleted_at IS NULL`, planID,
	).Scan(&owner)
	if err != nil {
		return nil, errors.New("plan not found")
	}
	if owner != userID {
		return nil, errors.New("plan not found")
	}
	c := &model.GrowthCheckin{}
	var dayOut time.Time
	err = r.Pool.QueryRow(ctx, `
		INSERT INTO growth_checkins(plan_id, user_id, day, note)
		VALUES ($1,$2,$3::date,$4)
		ON CONFLICT (plan_id, day) DO UPDATE SET note=EXCLUDED.note
		RETURNING id, plan_id, user_id, day, note, created_at`,
		planID, userID, day.Format("2006-01-02"), note,
	).Scan(&c.ID, &c.PlanID, &c.UserID, &dayOut, &c.Note, &c.CreatedAt)
	if err != nil {
		return nil, err
	}
	c.Day = dayOut.Format("2006-01-02")
	return c, nil
}

// ListCheckinsRecent returns check-ins for a plan in last N days.
func (r *GrowthRepo) ListCheckinsRecent(ctx context.Context, userID, planID uuid.UUID, days int) ([]model.GrowthCheckin, error) {
	rows, err := r.Pool.Query(ctx, `
		SELECT id, plan_id, user_id, day, note, created_at
		FROM growth_checkins
		WHERE user_id=$1 AND plan_id=$2 AND day >= (CURRENT_DATE - $3::int)
		ORDER BY day DESC`, userID, planID, days)
	if err != nil {
		return nil, err
	}
	defer rows.Close()
	var out []model.GrowthCheckin
	for rows.Next() {
		var c model.GrowthCheckin
		var dayOut time.Time
		if err := rows.Scan(&c.ID, &c.PlanID, &c.UserID, &dayOut, &c.Note, &c.CreatedAt); err != nil {
			return nil, err
		}
		c.Day = dayOut.Format("2006-01-02")
		out = append(out, c)
	}
	return out, rows.Err()
}

// ListMoodsRecent for companion trail (reuse moods table).
func (r *GrowthRepo) ListMoodsRecent(ctx context.Context, userID uuid.UUID, days int) ([]model.Mood, error) {
	rows, err := r.Pool.Query(ctx, `
		SELECT id, user_id, day, score, note, created_at
		FROM moods
		WHERE user_id=$1 AND deleted_at IS NULL AND day >= (CURRENT_DATE - $2::int)
		ORDER BY day DESC`, userID, days)
	if err != nil {
		return nil, err
	}
	defer rows.Close()
	var out []model.Mood
	for rows.Next() {
		var m model.Mood
		var dayOut time.Time
		if err := rows.Scan(&m.ID, &m.UserID, &dayOut, &m.Score, &m.Note, &m.CreatedAt); err != nil {
			return nil, err
		}
		m.Day = dayOut.Format("2006-01-02")
		out = append(out, m)
	}
	return out, rows.Err()
}

// ErrNoRows re-export helper.
var ErrNoRows = pgx.ErrNoRows