package store

import (
	"context"
	"database/sql"
	"fmt"
	"strings"
	"time"
)

// Answer is an admin reply to a question.
type Answer struct {
	QuestionID string
	AuthorID   string
	AuthorName string
	Body       string
	CreatedAt  string
	UpdatedAt  string
	db         *sql.DB
}

// NewAnswer returns an Answer bound to db.
func NewAnswer(db *sql.DB) *Answer {
	return &Answer{db: db}
}

// Upsert inserts or updates the answer for QuestionID.
func (a *Answer) Upsert(ctx context.Context) error {
	if a == nil || a.db == nil {
		return fmt.Errorf("answer: no database")
	}
	a.Body = strings.TrimSpace(a.Body)
	now := time.Now().UTC().Format(time.RFC3339)
	if a.CreatedAt == "" {
		a.CreatedAt = now
	}
	a.UpdatedAt = now
	_, err := a.db.ExecContext(ctx, `
INSERT INTO answers (question_id, author_id, body, created_at, updated_at) VALUES ($1, $2, $3, $4, $5)
ON CONFLICT (question_id) DO UPDATE SET body = excluded.body, author_id = excluded.author_id, updated_at = excluded.updated_at`,
		a.QuestionID, a.AuthorID, a.Body, a.CreatedAt, a.UpdatedAt)
	return err
}

func GetAnswer(ctx context.Context, db *sql.DB, questionID string) (*Answer, error) {
	var a Answer
	err := db.QueryRowContext(ctx, `
SELECT a.question_id, a.author_id, u.name, a.body, a.created_at, a.updated_at
FROM answers a
JOIN users u ON u.id = a.author_id
WHERE a.question_id = $1`, questionID).Scan(&a.QuestionID, &a.AuthorID, &a.AuthorName, &a.Body, &a.CreatedAt, &a.UpdatedAt)
	if err != nil {
		return nil, err
	}
	a.db = db
	return &a, nil
}