package db

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

	"github.com/google/uuid"

	"github.com/orohi/vpn-panel/internal/models"
)

func scanNode(scanner interface {
	Scan(dest ...any) error
}) (*models.Node, error) {
	n := &models.Node{}
	var lastSeen sql.NullTime
	var status string
	err := scanner.Scan(
		&n.ID, &n.Name, &n.Host, &n.SSHPort, &n.SSHUser, &n.SSHAuthType, &n.SSHSecretEnc,
		&n.NodePort, &n.SecretKey, &status, &n.InstallMode, &n.LastError, &n.InstallLog,
		&n.AgentVersion, &lastSeen, &n.CreatedAt, &n.UpdatedAt,
	)
	if err != nil {
		return nil, err
	}
	n.Status = models.NodeStatus(status)
	if lastSeen.Valid {
		t := lastSeen.Time
		n.LastSeenAt = &t
	}
	return n, nil
}

const nodeColumns = `
id, name, host, ssh_port, ssh_user, ssh_auth_type, ssh_secret_enc,
node_port, secret_key, status, install_mode, last_error, install_log,
agent_version, last_seen_at, created_at, updated_at`

func CreateNode(db *sql.DB, n *models.Node) error {
	if n.ID == uuid.Nil {
		n.ID = uuid.New()
	}
	now := time.Now().UTC()
	n.CreatedAt = now
	n.UpdatedAt = now
	if n.Status == "" {
		n.Status = models.NodeStatusPending
	}
	_, err := db.Exec(`
INSERT INTO nodes (
  id, name, host, ssh_port, ssh_user, ssh_auth_type, ssh_secret_enc,
  node_port, secret_key, status, install_mode, last_error, install_log,
  agent_version, last_seen_at, created_at, updated_at
) VALUES (
  $1,$2,$3,$4,$5,$6,$7,$8,$9,$10,$11,$12,$13,$14,$15,$16,$17
)`,
		n.ID, n.Name, n.Host, n.SSHPort, n.SSHUser, n.SSHAuthType, n.SSHSecretEnc,
		n.NodePort, n.SecretKey, string(n.Status), n.InstallMode, n.LastError, n.InstallLog,
		n.AgentVersion, n.LastSeenAt, n.CreatedAt, n.UpdatedAt,
	)
	return err
}

func GetNode(db *sql.DB, id uuid.UUID) (*models.Node, error) {
	row := db.QueryRow(`SELECT `+nodeColumns+` FROM nodes WHERE id = $1`, id)
	n, err := scanNode(row)
	if err == sql.ErrNoRows {
		return nil, nil
	}
	return n, err
}

func ListNodes(db *sql.DB) ([]models.Node, error) {
	rows, err := db.Query(`SELECT ` + nodeColumns + ` FROM nodes ORDER BY created_at DESC`)
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	var list []models.Node
	for rows.Next() {
		n, err := scanNode(rows)
		if err != nil {
			return nil, err
		}
		list = append(list, *n)
	}
	return list, rows.Err()
}

func UpdateNodeStatus(db *sql.DB, id uuid.UUID, status models.NodeStatus, lastError string) error {
	_, err := db.Exec(`
UPDATE nodes
SET status = $2, last_error = $3, updated_at = NOW()
WHERE id = $1`, id, string(status), lastError)
	return err
}

func ClearNodeInstallLog(db *sql.DB, id uuid.UUID) error {
	_, err := db.Exec(`UPDATE nodes SET install_log = '', updated_at = NOW() WHERE id = $1`, id)
	return err
}

func AppendNodeInstallLog(db *sql.DB, id uuid.UUID, chunk string) error {
	_, err := db.Exec(`
UPDATE nodes
SET install_log = CASE
  WHEN install_log = '' OR install_log IS NULL THEN $2
  ELSE install_log || E'\n' || $2
END, updated_at = NOW()
WHERE id = $1`, id, strings.TrimRight(chunk, "\n"))
	return err
}

func MarkNodeSeen(db *sql.DB, id uuid.UUID, version string, status models.NodeStatus) error {
	_, err := db.Exec(`
UPDATE nodes
SET last_seen_at = NOW(), agent_version = $2, status = $3, last_error = '', updated_at = NOW()
WHERE id = $1`, id, version, string(status))
	return err
}

func DeleteNode(db *sql.DB, id uuid.UUID) error {
	res, err := db.Exec(`DELETE FROM nodes WHERE id = $1`, id)
	if err != nil {
		return err
	}
	n, err := res.RowsAffected()
	if err != nil {
		return err
	}
	if n == 0 {
		return fmt.Errorf("node not found")
	}
	return nil
}