package db

import (
	"database/sql"
	"encoding/json"
	"errors"
	"log"

	"git.beisel.it/florian/hostname-service/models"
	"github.com/golang-migrate/migrate/v4"
	_ "github.com/golang-migrate/migrate/v4/database/sqlite3"
	_ "github.com/golang-migrate/migrate/v4/source/file"
	_ "github.com/mattn/go-sqlite3"
	"golang.org/x/crypto/bcrypt"
)

var DB *sql.DB

// Initialize the database and create tables if they don't exist
func Init() {
	var err error
	DB, err = sql.Open("sqlite3", "hostname-service.db")
	if err != nil {
		log.Fatalf("Error opening database: %v", err)
	}

	m, err := migrate.New(
		"file://db/migrations/",
		"sqlite3://hostname-service.db",
	)

	if err != nil {
		log.Fatalf("Migration initialization failed: %v", err)
	}

	// Apply all up migrations
	if err := m.Up(); err != nil && err != migrate.ErrNoChange {
		log.Fatalf("Migration up failed: %v", err)
	}

	// Check if users table is empty
	var userCount int
	err = DB.QueryRow("SELECT COUNT(*) FROM users").Scan(&userCount)
	if err != nil {
		log.Fatalf("Error checking users table: %v", err)
	}

	// If there are no users, create a default admin user
	if userCount == 0 {
		hashedPassword, err := bcrypt.GenerateFromPassword([]byte("defaultPassword"), bcrypt.DefaultCost)
		if err != nil {
			log.Fatalf("Error hashing password: %v", err)
		}

		_, err = DB.Exec("INSERT INTO users (username, password) VALUES (?, ?)", "admin", string(hashedPassword))
		if err != nil {
			log.Fatalf("Error creating default admin user: %v", err)
		}

		log.Println("Default admin user created")
	}

	log.Println("Database migrations applied successfully")
}

func CreateUser(user *models.User) error {
	statement, err := DB.Prepare("INSERT INTO users(username, password) VALUES (?, ?)")
	if err != nil {
		return err
	}
	_, err = statement.Exec(user.Username, user.Password)
	return err
}

func InsertHostname(category string, hostname string, paramsJSON []byte) error {
	_, err := DB.Exec("INSERT INTO hostnames (category, hostname, parameters) VALUES (?, ?, ?)", category, hostname, paramsJSON)
	if err != nil {
		log.Printf("Error inserting hostname into DB: %v", err)
		return err
	}
	return nil
}

func UpdateHostname(category string, oldhostname string, hostname string, paramsJSON []byte) error {
	_, err := DB.Exec("UPDATE hostnames set category = ?, hostname =?, parameters =? where category = ? and hostname = ?", category, hostname, paramsJSON, category, oldhostname)
	if err != nil {
		log.Printf("Error inserting hostname into DB: %v", err)
		return err
	}
	return nil
}

func DeleteHostname(category string, hostname string) error {
	log.Printf("Soft-Deleting hostname: %v in category: %v", category, hostname)
	_, err := DB.Exec("UPDATE hostnames set deleted = true where category = ? and hostname = ?", category, hostname)
	if err != nil {
		log.Printf("Error deleting hostname from DB: %v", err)
		return err
	}
	return nil
}

// HostnameExists checks if a hostname exists within a given category
func HostnameExists(category string, hostname string) (bool, error) {
	var exists bool

	query := "SELECT EXISTS(SELECT 1 FROM hostnames WHERE category = ? AND hostname = ?)"
	err := DB.QueryRow(query, category, hostname).Scan(&exists)
	if err != nil {
		if err == sql.ErrNoRows {
			// No rows found, meaning the hostname does not exist
			return false, nil
		}
		// An actual error occurred
		return false, err
	}

	return exists, nil
}

func GetMaxNumberForCategory(category string) (int, error) {
	var maxResult sql.NullInt64
	err := DB.QueryRow("SELECT MAX(CAST(json_extract(parameters, '$.Number') AS INTEGER)) FROM hostnames WHERE category = ?", category).Scan(&maxResult)
	if err != nil {
		log.Printf("Error querying max number for category %s: %v", category, err)
		return 0, err
	}
	if !maxResult.Valid {
		return 0, nil // No rows found, start with 0
	}
	return int(maxResult.Int64), nil
}

func GetHostnamesByCategory(category string) ([]models.Hostname, error) {
	var hostnames []models.Hostname

	rows, err := DB.Query("SELECT id, category, hostname, parameters, created_at FROM hostnames WHERE category = ? and deleted = false", category)
	if err != nil {
		log.Printf("Error querying hostnames: %v", err)
		return nil, err
	}
	defer rows.Close()

	for rows.Next() {
		var h models.Hostname
		var paramsJSON string
		err := rows.Scan(&h.ID, &h.Category, &h.Hostname, &paramsJSON, &h.CreatedAt)
		if err != nil {
			log.Printf("Error scanning hostname: %v", err)
			return nil, err
		}
		// Unmarshal parameters JSON
		err = json.Unmarshal([]byte(paramsJSON), &h.Parameters)
		if err != nil {
			log.Printf("Error unmarshaling parameters: %v", err)
			return nil, err
		}
		hostnames = append(hostnames, h)
	}

	return hostnames, nil
}

func GetHostnameByCategoryAndName(category string, hostname string) (models.Hostname, error) {
	var host models.Hostname
	var paramsJSON string

	row, err := DB.Query("SELECT id, category, hostname, parameters, created_at FROM hostnames where category = ? and hostname = ? and deleted = false", category, hostname)
	if err != nil {
		log.Printf("Error querying hostname: %v", err)
		return models.Hostname{}, err
	}
	defer row.Close()

	if !row.Next() {
		log.Printf("no rows found for category %s and hostname %s", category, hostname)
		return models.Hostname{}, errors.New("no rows found")
	}

	err = row.Scan(&host.ID, &host.Category, &host.Hostname, &paramsJSON, &host.CreatedAt)
	if err != nil {
		log.Printf("Error scanning hostname: %v", err)
		return models.Hostname{}, err
	}
	err = json.Unmarshal([]byte(paramsJSON), &host.Parameters)
	if err != nil {
		log.Printf("Error unmarshaling parameters: %v", err)
		return models.Hostname{}, nil
	}

	return host, nil
}