package core

import (
	"context"
	"errors"
	"time"

	"github.com/jackc/pgx/v5"
)

type Thread struct {
	ID            string    `json:"id"`
	InboxID       string    `json:"inbox_id"`
	Subject       *string   `json:"subject,omitempty"`
	LastMessageID *string   `json:"last_message_id,omitempty"`
	MessageCount  int       `json:"message_count"`
	Labels        []string  `json:"labels"`
	CreatedAt     time.Time `json:"created_at"`
	UpdatedAt     time.Time `json:"updated_at"`
}

const threadCols = `id::text, inbox_id::text, subject, last_message_id::text, message_count, labels, created_at, updated_at`

func scanThread(row pgx.Row) (Thread, error) {
	var t Thread
	err := row.Scan(&t.ID, &t.InboxID, &t.Subject, &t.LastMessageID, &t.MessageCount, &t.Labels, &t.CreatedAt, &t.UpdatedAt)
	return t, err
}

func (s *Service) ListThreads(ctx context.Context, inboxID string) ([]Thread, error) {
	rows, err := s.pool.Query(ctx,
		`SELECT `+threadCols+` FROM threads WHERE inbox_id = $1 ORDER BY updated_at DESC`, inboxID)
	if err != nil {
		return nil, err
	}
	defer rows.Close()
	out := []Thread{}
	for rows.Next() {
		t, err := scanThread(rows)
		if err != nil {
			return nil, err
		}
		out = append(out, t)
	}
	return out, rows.Err()
}

func (s *Service) GetThread(ctx context.Context, id string) (Thread, error) {
	t, err := scanThread(s.pool.QueryRow(ctx, `SELECT `+threadCols+` FROM threads WHERE id = $1`, id))
	if errors.Is(err, pgx.ErrNoRows) {
		return Thread{}, ErrNotFound
	}
	return t, err
}