package db

import (
	"context"

	"github.com/flatrender/notification-svc/internal/models"
	"github.com/google/uuid"
	"github.com/jackc/pgx/v5"
)

func (s *Store) ListCampaigns(ctx context.Context, tenantID uuid.UUID) ([]*models.Campaign, error) {
	rows, err := s.pool.Query(ctx,
		`SELECT id, tenant_id, name, channel, audience, subject, body_html, template_code,
		        status, total_count, sent_count, failed_count, created_at, sent_at
		 FROM notification.campaigns WHERE tenant_id = $1 ORDER BY created_at DESC`, tenantID)
	if err != nil {
		return nil, err
	}
	defer rows.Close()
	var out []*models.Campaign
	for rows.Next() {
		c := &models.Campaign{}
		if err := rows.Scan(&c.ID, &c.TenantID, &c.Name, &c.Channel, &c.Audience, &c.Subject,
			&c.BodyHTML, &c.TemplateCode, &c.Status, &c.TotalCount, &c.SentCount, &c.FailedCount,
			&c.CreatedAt, &c.SentAt); err != nil {
			return nil, err
		}
		out = append(out, c)
	}
	return out, rows.Err()
}

func (s *Store) GetCampaign(ctx context.Context, id, tenantID uuid.UUID) (*models.Campaign, error) {
	c := &models.Campaign{}
	err := s.pool.QueryRow(ctx,
		`SELECT id, tenant_id, name, channel, audience, subject, body_html, template_code,
		        status, total_count, sent_count, failed_count, created_at, sent_at
		 FROM notification.campaigns WHERE id = $1 AND tenant_id = $2`, id, tenantID).
		Scan(&c.ID, &c.TenantID, &c.Name, &c.Channel, &c.Audience, &c.Subject, &c.BodyHTML,
			&c.TemplateCode, &c.Status, &c.TotalCount, &c.SentCount, &c.FailedCount, &c.CreatedAt, &c.SentAt)
	if err == pgx.ErrNoRows {
		return nil, nil
	}
	return c, err
}

func (s *Store) CreateCampaign(ctx context.Context, tenantID uuid.UUID, req models.CreateCampaignRequest) (*models.Campaign, error) {
	audience := req.Audience
	if audience == "" {
		audience = "all"
	}
	var id uuid.UUID
	err := s.pool.QueryRow(ctx,
		`INSERT INTO notification.campaigns (tenant_id, name, channel, audience, subject, body_html, template_code)
		 VALUES ($1,$2,$3,$4,$5,$6,$7) RETURNING id`,
		tenantID, req.Name, req.Channel, audience, req.Subject, req.BodyHTML, req.TemplateCode).Scan(&id)
	if err != nil {
		return nil, err
	}
	return s.GetCampaign(ctx, id, tenantID)
}

func (s *Store) DeleteCampaign(ctx context.Context, id, tenantID uuid.UUID) error {
	_, err := s.pool.Exec(ctx, `DELETE FROM notification.campaigns WHERE id=$1 AND tenant_id=$2`, id, tenantID)
	return err
}

func (s *Store) UpdateCampaignResult(ctx context.Context, id uuid.UUID, status string, total, sent, failed int) error {
	_, err := s.pool.Exec(ctx,
		`UPDATE notification.campaigns SET status=$2, total_count=$3, sent_count=$4, failed_count=$5,
		        sent_at = CASE WHEN $2 IN ('Sent','Failed') THEN NOW() ELSE sent_at END
		 WHERE id=$1`, id, status, total, sent, failed)
	return err
}

// ResolveAudience returns recipient contact strings (email or phone) for a campaign
// segment, read cross-schema from identity.users (same database).
func (s *Store) ResolveAudience(ctx context.Context, tenantID uuid.UUID, channel, audience string, limit int) ([]string, error) {
	col := "email"
	notNull := "email IS NOT NULL AND email <> ''"
	if channel == "sms" {
		col = "phone_number"
		notNull = "phone_number IS NOT NULL AND phone_number <> ''"
	}
	where := "tenant_id = $1 AND deleted_at IS NULL AND ban_account = FALSE AND " + notNull
	switch audience {
	case "verified":
		if channel == "sms" {
			where += " AND phone_verified = TRUE"
		} else {
			where += " AND email_verified = TRUE"
		}
	case "with_plan":
		where += " AND EXISTS (SELECT 1 FROM identity.user_plans up WHERE up.user_id = identity.users.id AND (up.expires_at IS NULL OR up.expires_at > NOW()))"
	}
	q := "SELECT " + col + " FROM identity.users WHERE " + where + " LIMIT $2"
	rows, err := s.pool.Query(ctx, q, tenantID, limit)
	if err != nil {
		return nil, err
	}
	defer rows.Close()
	var out []string
	for rows.Next() {
		var v string
		if err := rows.Scan(&v); err == nil && v != "" {
			out = append(out, v)
		}
	}
	return out, rows.Err()
}