package models

import (
	"database/sql"
	"errors"
	"fmt"
	"log"
	"net/http"
	"smt/utils/token"

	"github.com/gin-gonic/gin"
	"golang.org/x/crypto/bcrypt"
)

type User struct {
	UserId   int    `db:"UserId" json:"userId"`
	RoleId   int    `db:"RoleId" json:"roleId"`
	UserName string `db:"UserName" json:"userName"`
	Password string `db:"Password" json:"-"`
	LdapUser bool   `db:"LdapUser" json:"ldapUser"`
	LdapDn   string `db:"LdapDN" json:"ldapDn"`
}

type UserRole struct {
	User
	RoleName string `db:"RoleName"`
	ReadOnly bool   `db:"ReadOnly"`
	Admin    bool   `db:"Admin"`
}

func (u *User) SaveUser() (*User, error) {

	var err error

	// Validate username not already in use
	_, err = GetUserByName(u.UserName)
	if err != nil && err.Error() == "user not found" {
		log.Printf("SaveUser confirmed no existing user, continuing with creation of user '%s'\n", u.UserName)
		result, err := db.NamedExec((`INSERT INTO users (RoleId, UserName, Password, LdapUser, LdapDn) VALUES (:RoleId, :UserName, :Password, :LdapUser, :LdapDN)`), u)

		if err != nil {
			log.Printf("SaveUser error executing sql record : '%s'\n", err)
			return &User{}, err
		} else {
			affected, _ := result.RowsAffected()
			id, _ := result.LastInsertId()
			log.Printf("SaveUser insert returned result id '%d' affecting %d row(s).\n", id, affected)
		}
	} else {
		log.Printf("SaveUser Username already exists : '%v'\n", err)
	}

	return u, nil
}

func (u *User) DeleteUser() error {

	// Validate username exists
	_, err := GetUserByName(u.UserName)
	if err != nil {
		log.Printf("DeleteUser error finding user account to remove : '%s'\n", err)
		return err
	} else {
		log.Printf("DeleteUser confirmed user exists, continuing with deletion of user '%s'\n", u.UserName)
		result, err := db.NamedExec((`DELETE FROM users WHERE UserName = :UserName`), u)

		if err != nil {
			log.Printf("DeleteUser error executing sql delete : '%s'\n", err)
			return err
		} else {
			affected, _ := result.RowsAffected()
			id, _ := result.LastInsertId()
			log.Printf("DeleteUser returned result id '%d' affecting %d row(s).\n", id, affected)
		}

	}

	return nil
}

func VerifyPassword(password, hashedPassword string) error {
	log.Printf("VerifyPassword comparing input against hashed value '%s'\n", hashedPassword)
	return bcrypt.CompareHashAndPassword([]byte(hashedPassword), []byte(password))
}

func LoginCheck(username string, password string) (string, error) {

	var err error

	u := User{}

	// Query database for matching user object
	err = db.QueryRowx("SELECT * FROM Users WHERE Username=?", username).StructScan(&u)

	if err != nil {
		if err == sql.ErrNoRows {
			// check LDAP if enabled
			if LdapEnabled {
				ldapUser, err := LdapLoginCheck(username, password)
				if err != nil {
					errString := fmt.Sprintf("LoginCheck error checking LDAP for user : '%s'\n", err)
					log.Print(errString)
					return "", errors.New(errString)

				}

				if ldapUser == (User{}) {
					errString := fmt.Sprintf("LoginCheck user not found in LDAP : '%s'\n", err)
					log.Print(errString)
					return "", errors.New(errString)
				} else {
					u = ldapUser
				}
			} else {
				// LDAP is not enabled, if user is not in the database then they can't login
				return "", errors.New("specified user not found in database")
			}
		}
	} else {
		log.Printf("LoginCheck retrieved user '%v' from database\n", u)
	}

	if !u.LdapUser {
		err = VerifyPassword(password, u.Password)

		if err != nil && err == bcrypt.ErrMismatchedHashAndPassword {
			log.Printf("LoginCheck says password doesn't match stored hash.\n")
			return "", err
		} else {
			log.Printf("LoginCheck verified password against stored hash.\n")
		}
	} else {
		log.Printf("LoginCheck no need to verify password in database for LDAP user\n")
	}

	token, err := token.GenerateToken(uint(u.UserId))

	if err != nil {
		log.Printf("LoginCheck error generating token : '%s'\n", err)
		return "", err
	}

	return token, nil

}

func LdapLoginCheck(username string, password string) (User, error) {
	var u User
	u.UserName = username

	// try to get LDAP group membership
	groups, err := GetLdapGroupMembership(username, password)
	if err != nil {
		if err.Error() == "invalid user credentials" {
			return u, nil
		} else {
			return u, err
		}
	}

	// Compare all roles against the list of user's group membership
	roleList, err := QueryRoles()
	if err != nil {
		return u, err
	}

	matchFound := false
	for _, role := range roleList {
		for _, group := range groups {
			if role.LdapGroup == group {
				log.Printf("Found match with role '%s' and LDAP group '%s', user is allowed role ID '%d'\n", role.RoleName, role.LdapGroup, role.RoleId)
				u.RoleId = role.RoleId
				matchFound = true
				break
			} else {
				//log.Printf("Role '%s' with LDAP group '%s' not match user group '%s'\n", role.RoleName, role.LdapGroup, group)
			}
		}
	}

	if matchFound {
		// If we found a match, then store user with appropriate role ID
		u.SaveUser()
	}

	return u, nil
}

// StoreLdapUser creates a user record in the database and returns the corresponding userId
func StoreLdapUser(u *User) error {

	// TODO

	return nil
}

func GetUserByID(uid uint) (User, error) {

	var u User

	// Query database for matching user object
	err := db.QueryRowx("SELECT * FROM users WHERE UserId=?", uid).StructScan(&u)
	if err != nil {
		return u, errors.New("user not found")
	}
	/*
		if err := DB.First(&u, uid).Error; err != nil {
			return u, errors.New("User not found!")
		}
	*/
	//u.PrepareGive()

	return u, nil

}

func GetUserByName(username string) (User, error) {

	var u User

	// Query database for matching user object
	err := db.QueryRowx("SELECT * FROM users WHERE UserName=?", username).StructScan(&u)
	if err != nil {
		return u, errors.New("user not found")
	}

	return u, nil
}

func GetUserRoleByID(uid uint) (UserRole, error) {

	var ur UserRole

	// Query database for matching user object
	log.Printf("GetUserRoleByID querying for userid '%d'\n", uid)
	err := db.QueryRowx("SELECT users.UserId, users.RoleId, users.UserName, users.Password, users.LdapUser, users.LdapDN, roles.RoleName, roles.ReadOnly, roles.Admin FROM users INNER JOIN roles ON users.RoleId = roles.RoleId WHERE users.UserId=?", uid).StructScan(&ur)
	if err != nil {
		log.Printf("GetUserRoleByID received error when querying database : '%s'\n", err)
		return ur, errors.New("GetUserRoleByID user not found")
	}

	return ur, nil
}

func GetUserRoleFromToken(c *gin.Context) (UserRole, error) {

	var ur UserRole

	user_id, err := token.ExtractTokenID(c)

	if err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
		return ur, err
	}

	// Query database for matching user object
	log.Printf("GetUserRoleFromToken querying for userid '%d'\n", user_id)
	err = db.QueryRowx("SELECT users.UserId, users.RoleId, users.UserName, users.Password, users.LdapUser, users.LdapDN, roles.RoleName, roles.ReadOnly, roles.Admin FROM users INNER JOIN roles ON users.RoleId = roles.RoleId WHERE users.UserId=?", user_id).StructScan(&ur)
	if err != nil {
		log.Printf("GetUserRoleFromToken received error when querying database : '%s'\n", err)
		return ur, errors.New("GetUserRoleFromToken user not found")
	}

	return ur, nil
}

func QueryUsers() ([]User, error) {
	var results []User

	// Query database for role definitions
	rows, err := db.Queryx("SELECT * FROM users")

	if err != nil {
		log.Printf("QueryUsers error executing sql record : '%s'\n", err)
		return results, err
	} else {
		// parse all the results into a slice
		for rows.Next() {
			var u User
			err = rows.StructScan(&u)
			if err != nil {
				log.Printf("QueryUsers error parsing sql record : '%s'\n", err)
				return results, err
			}
			results = append(results, u)

		}
		log.Printf("QueryUsers retrieved '%d' results\n", len(results))
	}

	return results, nil
}