package database

import (
	"database/sql"
	"errors"
	"time"

	"git.noroutes.net/NoRoutes/vibetunes/internal/idgen"
)

type Session struct {
	ID        string
	UserID    string
	CreatedAt time.Time
	ExpiresAt time.Time
	UserAgent string
	IPAddress string
}

func CreateSession(db *sql.DB, userID string, ttl time.Duration, userAgent, ip string) (*Session, error) {
	id := idgen.New("se")
	expires := time.Now().Add(ttl).UTC()
	_, err := db.Exec(`INSERT INTO sessions (id, user_id, expires_at, user_agent, ip_address) VALUES (?, ?, ?, ?, ?)`,
		id, userID, expires.Format(timeLayout), userAgent, ip)
	if err != nil {
		return nil, err
	}
	return GetSession(db, id)
}

const timeLayout = "2006-01-02T15:04:05.000Z"

func GetSession(db *sql.DB, id string) (*Session, error) {
	var s Session
	var createdAt, expiresAt string
	err := db.QueryRow(`SELECT id, user_id, created_at, expires_at, user_agent, ip_address FROM sessions WHERE id = ?`, id).
		Scan(&s.ID, &s.UserID, &createdAt, &expiresAt, &s.UserAgent, &s.IPAddress)
	if errors.Is(err, sql.ErrNoRows) {
		return nil, ErrNotFound
	}
	if err != nil {
		return nil, err
	}
	s.CreatedAt, _ = parseTime(createdAt)
	s.ExpiresAt, _ = parseTime(expiresAt)
	return &s, nil
}

func DeleteSession(db *sql.DB, id string) error {
	_, err := db.Exec(`DELETE FROM sessions WHERE id = ?`, id)
	return err
}

// DeleteUserSessions revokes every session for a user (e.g. on password
// change or "log out everywhere").
func DeleteUserSessions(db *sql.DB, userID string) error {
	_, err := db.Exec(`DELETE FROM sessions WHERE user_id = ?`, userID)
	return err
}

func ListUserSessions(db *sql.DB, userID string) ([]*Session, error) {
	rows, err := db.Query(`SELECT id, user_id, created_at, expires_at, user_agent, ip_address FROM sessions WHERE user_id = ? ORDER BY created_at DESC`, userID)
	if err != nil {
		return nil, err
	}
	defer rows.Close()
	var out []*Session
	for rows.Next() {
		var s Session
		var createdAt, expiresAt string
		if err := rows.Scan(&s.ID, &s.UserID, &createdAt, &expiresAt, &s.UserAgent, &s.IPAddress); err != nil {
			return nil, err
		}
		s.CreatedAt, _ = parseTime(createdAt)
		s.ExpiresAt, _ = parseTime(expiresAt)
		out = append(out, &s)
	}
	return out, rows.Err()
}

// DeleteExpiredSessions purges sessions past their expiry, keeping the
// table small over a long-running server's lifetime.
func DeleteExpiredSessions(db *sql.DB) error {
	_, err := db.Exec(`DELETE FROM sessions WHERE expires_at < strftime('%Y-%m-%dT%H:%M:%fZ','now')`)
	return err
}