package models

import (
	"errors"
	"fmt"
	"log"
	"os"
	"reflect"

	"smt/utils"

	"github.com/jmoiron/sqlx"
	"golang.org/x/crypto/bcrypt"
	_ "modernc.org/sqlite"
)

var db *sqlx.DB

const (
	sqlFile = "smt.db"
)

const createUsers string = `
	CREATE TABLE IF NOT EXISTS users (
		UserId INTEGER PRIMARY KEY AUTOINCREMENT,
		GroupId INTEGER,
		UserName VARCHAR,
		Password VARCHAR,
		Admin BOOLEAN DEFAULT 0,
		LdapUser BOOLEAN DEFAULT 0
	);
`

const createSafes string = `
	CREATE TABLE IF NOT EXISTS safes (
		SafeId INTEGER PRIMARY KEY AUTOINCREMENT,
		SafeName VARCHAR
	);
`

const createGroups string = `
	CREATE TABLE IF NOT EXISTS groups (
		GroupId INTEGER PRIMARY KEY AUTOINCREMENT,
		GroupName VARCHAR,
		LdapGroup BOOLEAN DEFAULT 0,
		LdapDn VARCHAR DEFAULT '',
		Admin BOOLEAN DEFAULT 0
	);
`

const createPermissions = `
	CREATE TABLE IF NOT EXISTS permissions (
		PermissionId INTEGER PRIMARY KEY AUTOINCREMENT,
		Description VARCHAR DEFAULT '',
		ReadOnly BOOLEAN DEFAULT 0,
		SafeId INTEGER,
		UserId INTEGER DEFAULT 0,
		GroupId INTEGER DEFAULT 0,
		FOREIGN KEY (SafeId) REFERENCES safes(SafeId)
	);
`

const createSecrets string = `
	CREATE TABLE IF NOT EXISTS secrets (
		SecretId INTEGER PRIMARY KEY AUTOINCREMENT,
		SafeId INTEGER,
		DeviceName VARCHAR,
		DeviceCategory VARCHAR,
		UserName VARCHAR,
		Secret VARCHAR,
		LastUpdated datetime DEFAULT (datetime('1970-01-01 00:00:00')),
		FOREIGN KEY (SafeId) REFERENCES safes(SafeId)
	);
`

const createSchema string = `
	CREATE TABLE IF NOT EXISTS schema (
		Version INTEGER
	);
`

const createAudit string = `
	CREATE TABLE IF NOT EXISTS audit (
		AuditId INTEGER PRIMARY KEY AUTOINCREMENT,
		UserId INTEGER DEFAULT 0,
		SecretId INTEGER DEFAULT 0,
		EventText VARCHAR,
		EventTime datetime
	);
`

// Establish connection to sqlite database
func ConnectDatabase() {
	var err error

	// Try using sqlite as our database
	sqlPath := utils.GetFilePath(sqlFile)
	db, err = sqlx.Open("sqlite", sqlPath)

	if err != nil {
		log.Printf("Error opening sqlite database connection to file '%s' : '%s'\n", sqlPath, err)
		os.Exit(1)
	} else {
		log.Printf("Connected to sqlite database file '%s'\n", sqlPath)
	}

	//sqlx.NameMapper = func(s string) string { return s }

	// Make sure our tables exist
	CreateTables()

	//defer db.Close()
}

func DisconnectDatabase() {
	log.Printf("DisconnectDatabase called")
	defer db.Close()
}

func CreateTables() {
	var err error
	var rowCount int
	// Create database tables if it doesn't exist
	/*
		// Roles table should go first since other tables refer to it
		if _, err = db.Exec(createRoles); err != nil {
			log.Printf("Error checking roles table : '%s'", err)
			os.Exit(1)
		}
		rowCount, _ = CheckCount("roles")
		if rowCount == 0 {
			if _, err = db.Exec("INSERT INTO roles VALUES(1, 'Admin', false);"); err != nil {
				log.Printf("Error adding initial admin role : '%s'", err)
				os.Exit(1)
			}
			if _, err = db.Exec("INSERT INTO roles VALUES(2, 'UserRole', false);"); err != nil {
				log.Printf("Error adding initial user role : '%s'", err)
				os.Exit(1)
			}
			if _, err = db.Exec("INSERT INTO roles VALUES(3, 'GuestRole', true);"); err != nil {
				log.Printf("Error adding initial guest role : '%s'", err)
				os.Exit(1)
			}
		}
	*/

	// groups table
	if _, err = db.Exec(createGroups); err != nil {
		log.Printf("Error checking groups table : '%s'", err)
		os.Exit(1)
	}

	// Add initial groups
	rowCount, _ = CheckCount("groups")
	if rowCount == 0 {
		if _, err = db.Exec("INSERT INTO groups (GroupId, GroupName, Admin) VALUES(1, 'Administrators', 1);"); err != nil {
			log.Printf("Error adding initial group entry id 1 : '%s'", err)
			os.Exit(1)
		}
		if _, err = db.Exec("INSERT INTO groups (GroupId, GroupName, Admin) VALUES(2, 'Users', 0);"); err != nil {
			log.Printf("Error adding initial group entry id 2 : '%s'", err)
			os.Exit(1)
		}
	}

	// Users table
	if _, err = db.Exec(createUsers); err != nil {
		log.Printf("Error checking users table : '%s'", err)
		os.Exit(1)
	}
	rowCount, _ = CheckCount("users")
	if rowCount == 0 {
		// Check if there was an initial password defined in the .env file
		initialPassword := os.Getenv("INITIAL_PASSWORD")
		if initialPassword == "" {
			initialPassword = "password"
		} else if initialPassword[:4] == "$2a$" {
			log.Printf("CreateTables inital admin password is already a hash")
		} else {
			cryptText, _ := bcrypt.GenerateFromPassword([]byte(initialPassword), bcrypt.DefaultCost)
			initialPassword = string(cryptText)
		}
		if _, err = db.Exec("INSERT INTO users (UserId, GroupId, UserName, Password, LdapUser, Admin) VALUES(1, 1, 'Administrator', ?, false, true);", initialPassword); err != nil {
			log.Printf("Error adding initial admin role : '%s'", err)
			os.Exit(1)
		}
		if _, err = db.Exec("INSERT INTO users (UserId, GroupId, UserName, Password, LdapUser, Admin) VALUES(2, 2, 'User', ?, false, false);", initialPassword); err != nil {
			log.Printf("Error adding initial admin role : '%s'", err)
			os.Exit(1)
		}
	}

	// Safes table
	if _, err = db.Exec(createSafes); err != nil {
		log.Printf("Error checking safes table : '%s'", err)
		os.Exit(1)
	}
	// Create an initial safe
	rowCount, _ = CheckCount("safes")
	if rowCount == 0 {
		if _, err = db.Exec("INSERT INTO safes VALUES(1, 'Default Safe');"); err != nil {
			log.Printf("Error adding initial safe entry : '%s'", err)
			os.Exit(1)
		}
	}

	// Secrets table
	if _, err = db.Exec(createSecrets); err != nil {
		log.Printf("Error checking secrets table : '%s'", err)
		os.Exit(1)
	}

	// permissions table
	if _, err = db.Exec(createPermissions); err != nil {
		log.Printf("Error checking permissions table : '%s'", err)
		os.Exit(1)
	}

	// Add initial permissions
	rowCount, _ = CheckCount("permissions")
	if rowCount == 0 {
		if _, err = db.Exec("INSERT INTO permissions (Description, ReadOnly, GroupId, SafeId) VALUES('Default Admin Group Permission', false, 1, 1);"); err != nil {
			log.Printf("Error adding initial permissions entry userid 1 : '%s'", err)
			os.Exit(1)
		}
		if _, err = db.Exec("INSERT INTO permissions (Description, ReadOnly, SafeId, GroupId) VALUES('Default User Group Permission', false, 1, 2);"); err != nil {
			log.Printf("Error adding initial permissions entry userid 2 : '%s'", err)
			os.Exit(1)
		}
	}

	// Schema table should go last so we know if the database has a value in the schema table then everything was created properly
	if _, err = db.Exec(createSchema); err != nil {
		log.Printf("Error checking schema table : '%s'", err)
		os.Exit(1)
	}
	schemaCheck, _ := CheckColumnExists("schema", "Version")
	if !schemaCheck {
		if _, err = db.Exec("INSERT INTO schema VALUES(2);"); err != nil {
			log.Printf("Error adding initial schema version : '%s'", err)
			os.Exit(1)
		}
	}

	// Audit log table
	if _, err = db.Exec(createAudit); err != nil {
		log.Printf("Error checking audit table : '%s'", err)
		os.Exit(1)
	}

	// Remove users RoleId column
	userRoleIdCheck, _ := CheckColumnExists("users", "RoleId")
	if userRoleIdCheck {
		//_, err := db.Exec("ALTER TABLE users DROP COLUMN RoleId;")
		_, err := db.Exec(`
		PRAGMA foreign_keys=off;
		BEGIN TRANSACTION;
		ALTER TABLE users RENAME TO _users_old;
		CREATE TABLE users
		(
			UserId INTEGER PRIMARY KEY AUTOINCREMENT,
			GroupId INTEGER,
			UserName VARCHAR,
			Password VARCHAR,
			Admin BOOLEAN DEFAULT 0,
			LdapUser BOOLEAN DEFAULT 0
		);
		INSERT INTO users SELECT * FROM _users_old;
		COMMIT;
		PRAGMA foreign_keys=on;
		DROP TABLE _users_old;
		`)
		if err != nil {
			log.Printf("Error altering users table to drop RoleId column : '%s'\n", err)
			os.Exit(1)
		}
	}

	// Set any unassigned secrets to the default safe id
	if _, err = db.Exec("UPDATE users SET LdapUser = 0 WHERE LdapUser is null;"); err != nil {
		log.Printf("Error setting LdapUser flag to false for existing users : '%s'", err)
		os.Exit(1)
	}

	// Remove LdapGroup column from roles table
	ldapCheck, _ := CheckColumnExists("roles", "LdapGroup")
	if ldapCheck {
		_, err := db.Exec("ALTER TABLE roles DROP COLUMN LdapGroup;")
		if err != nil {
			log.Printf("Error altering roles table to renmove LdapGroup column : '%s'\n", err)
			os.Exit(1)
		}
	}

	// Add SafeId column to secrets table
	safeIdCheck, _ := CheckColumnExists("secrets", "SafeId")
	if !safeIdCheck {
		// Add the column for LdapGroup in the roles table
		_, err := db.Exec("ALTER TABLE secrets ADD COLUMN SafeId INTEGER REFERENCES safes(SafeId);")
		if err != nil {
			log.Printf("Error altering secrets table to add SafeId column : '%s'\n", err)
			os.Exit(1)
		}
	}

	// Set any unassigned secrets to the default safe id
	if _, err = db.Exec("UPDATE secrets SET SafeId = 1 WHERE SafeId is null;"); err != nil {
		log.Printf("Error setting safe ID of existing secrets : '%s'", err)
		os.Exit(1)
	}

	// Remove RoleId column from secrets table
	secretsRoleIdCheck, _ := CheckColumnExists("secrets", "RoleId")
	if secretsRoleIdCheck {
		_, err := db.Exec(`
		PRAGMA foreign_keys=off;
		BEGIN TRANSACTION;
		ALTER TABLE secrets RENAME TO _secrets_old;
		CREATE TABLE secrets
		(
			SecretId INTEGER PRIMARY KEY AUTOINCREMENT,
			RoleId INTEGER,
			SafeId INTEGER,
			DeviceName VARCHAR,
			DeviceCategory VARCHAR,
			UserName VARCHAR,
			Secret VARCHAR,
			FOREIGN KEY (SafeId) REFERENCES safes(SafeId)
		);
		INSERT INTO secrets SELECT SecretId, RoleId, SafeId, DeviceName, DeviceCategory, UserName, Secret FROM _secrets_old;
		ALTER TABLE secrets DROP COLUMN RoleId;
		COMMIT;
		PRAGMA foreign_keys=on;
		DROP TABLE _secrets_old;
		`)
		if err != nil {
			log.Printf("Error altering secrets table to remove RoleId column : '%s'\n", err)
			os.Exit(1)
		}
	}

	// Remove the Admin column from roles table
	rolesAdminCheck, _ := CheckColumnExists("roles", "Admin")
	if rolesAdminCheck {
		_, err := db.Exec("ALTER TABLE roles DROP COLUMN Admin;")
		if err != nil {
			log.Printf("Error altering roles table to remove Admin column : '%s'\n", err)
			os.Exit(1)
		}
	}

	// Remove the RoleId from permissiosn table
	permissionsRoleIdCheck, _ := CheckColumnExists("permissions", "RoleId")
	if permissionsRoleIdCheck {
		_, err := db.Exec(`
		PRAGMA foreign_keys=off;
		BEGIN TRANSACTION;
		ALTER TABLE permissions RENAME TO _permissions_old;
		CREATE TABLE permissions
		(
			PermissionId INTEGER PRIMARY KEY AUTOINCREMENT,
			Description VARCHAR DEFAULT '',
			ReadOnly BOOLEAN DEFAULT 0,
			SafeId INTEGER,
			UserId INTEGER DEFAULT 0,
			GroupId INTEGER DEFAULT 0,
			FOREIGN KEY (SafeId) REFERENCES safes(SafeId)
		);
		INSERT INTO permissions SELECT PermissionId, SafeId, UserId, GroupId, '' AS Description, 0 as ReadOnly FROM _permissions_old;
		UPDATE permissions SET ReadOnly = 0 WHERE ReadOnly is null;
		UPDATE permissions SET Description = '' WHERE Description is null;
		UPDATE permissions SET UserId = 0 WHERE UserId is null;
		UPDATE permissions SET GroupId = 0 WHERE GroupId is null;
		COMMIT;
		PRAGMA foreign_keys=on;
		DROP TABLE _permissions_old;
		`)
		if err != nil {
			log.Printf("Error altering permissions table to remove RoleId column : '%s'\n", err)
			os.Exit(1)
		}
	}

	secretsLastUpdatedCheck, _ := CheckColumnExists("secrets", "LastUpdated")
	if !secretsLastUpdatedCheck {
		// Add the column for LastUpdated in the secrets table
		_, err := db.Exec("ALTER TABLE secrets ADD COLUMN LastUpdated datetime DEFAULT (datetime('1970-01-01 00:00:00'));")
		if err != nil {
			log.Printf("Error altering secrets table to add LastUpdated column : '%s'\n", err)
			os.Exit(1)
		}
	}

	/*
		// Database updates added after initial version released
		ldapCheck, _ := CheckColumnExists("roles", "LdapGroup")

		if !ldapCheck {
			// Add the column for LdapGroup in the roles table
			_, err := db.Exec("ALTER TABLE roles ADD COLUMN LdapGroup VARCHAR DEFAULT '';")
			if err != nil {
				log.Printf("Error altering roles table to add LdapGroup column : '%s'\n", err)
				os.Exit(1)
			}
		}

		// Add the two LDAP columns to the users table if they weren't there
		ldapUserCheck, _ := CheckColumnExists("users", "LdapUser")
		if !ldapUserCheck {
			log.Printf("CreateTables creating ldap columns in user table")
			_, err := db.Exec("ALTER TABLE users ADD COLUMN LdapUser BOOLEAN DEFAULT 0;")
			if err != nil {
				log.Printf("Error altering users table to add LdapUser column : '%s'\n", err)
				os.Exit(1)
			}

			_, err = db.Exec("ALTER TABLE users ADD COLUMN LdapDn VARCHAR DEFAULT '';")
			if err != nil {
				log.Printf("Error altering users table to add LdapDn column : '%s'\n", err)
				os.Exit(1)
			}
		}
	*/

}

// Count the number of records in the sqlite database
// Borrowed from https://gist.github.com/trkrameshkumar/f4f1c00ef5d578561c96?permalink_comment_id=2687592#gistcomment-2687592
func CheckCount(tablename string) (int, error) {
	var count int
	stmt, err := db.Prepare("SELECT COUNT(*) as count FROM " + tablename)
	if err != nil {
		log.Printf("CheckCount error preparing sqlite statement : '%s'\n", err)
		return 0, err
	}
	err = stmt.QueryRow().Scan(&count)
	if err != nil {
		log.Printf("CheckCount error querying database record count : '%s'\n", err)
		return 0, err
	}
	stmt.Close() // or use defer rows.Close(), idc
	return count, nil
}

// From https://stackoverflow.com/a/60100045
func GenerateInsertMethod(q interface{}) (string, error) {
	if reflect.ValueOf(q).Kind() == reflect.Struct {
		query := fmt.Sprintf("INSERT INTO %s", reflect.TypeOf(q).Name())
		fieldNames := ""
		fieldValues := ""
		v := reflect.ValueOf(q)
		for i := 0; i < v.NumField(); i++ {
			if i == 0 {
				fieldNames = fmt.Sprintf("%s%s", fieldNames, v.Type().Field(i).Name)
			} else {
				fieldNames = fmt.Sprintf("%s, %s", fieldNames, v.Type().Field(i).Name)
			}
			switch v.Field(i).Kind() {
			case reflect.Int:
				if i == 0 {
					fieldValues = fmt.Sprintf("%s%d", fieldValues, v.Field(i).Int())
				} else {
					fieldValues = fmt.Sprintf("%s, %d", fieldValues, v.Field(i).Int())
				}
			case reflect.String:
				if i == 0 {
					fieldValues = fmt.Sprintf("%s\"%s\"", fieldValues, v.Field(i).String())
				} else {
					fieldValues = fmt.Sprintf("%s, \"%s\"", fieldValues, v.Field(i).String())
				}
			case reflect.Bool:
				var boolSet int8
				if v.Field(i).Bool() {
					boolSet = 1
				}
				if i == 0 {
					fieldValues = fmt.Sprintf("%s%d", fieldValues, boolSet)
				} else {
					fieldValues = fmt.Sprintf("%s, %d", fieldValues, boolSet)
				}
			default:
				log.Printf("Unsupported type '%s'\n", v.Field(i).Kind())
			}
		}
		query = fmt.Sprintf("%s(%s) VALUES (%s)", query, fieldNames, fieldValues)
		return query, nil
	}
	return "", errors.New("SqlGenerationError")
}

func CheckColumnExists(table string, column string) (bool, error) {
	var count int64
	rows, err := db.Queryx("SELECT COUNT(*) AS CNTREC FROM pragma_table_info('" + table + "') WHERE name='" + column + "';")
	if err != nil {
		log.Printf("CheckColumnExists error querying database for existence of column '%s' : '%s'\n", column, err)
		return false, err
	}
	defer rows.Close()
	for rows.Next() {
		// cols is an []interface{} of all of the column results
		cols, _ := rows.SliceScan()
		log.Printf("CheckColumnExists Value is '%v' for table '%s' and column '%s'\n", cols[0].(int64), table, column)
		count = cols[0].(int64)

		if count == 1 {
			return true, nil
		} else {
			return false, nil
		}
	}

	err = rows.Err()
	if err != nil {
		log.Printf("CheckColumnExists error getting results : '%s'\n", err)
		return false, err
	}

	return false, nil
}