package useCases

import (
	"RenewCMS/internal/domain/audit"
	"RenewCMS/internal/domain/contenttype"
	"RenewCMS/internal/domain/hash"
	"RenewCMS/internal/domain/invite"
	"RenewCMS/internal/domain/mail"
	"RenewCMS/internal/domain/role"
	"RenewCMS/internal/domain/user"
	"context"
	"errors"
	"strings"
	"time"
)

type CreateInviteUseCase struct {
	userRepository   user.Repository
	inviteRepository invite.Repository
	roles            role.Repository
	contentTypes     contenttype.Repository
	hasher           hash.Hasher
	mailer           inviteMailer
	recorder         audit.Recorder
}

type CreateInviteCommand struct {
	Caller    ContentCaller
	Email     string
	InvitedBy uint32
	RoleID    uint32
}

func NewCreateInviteUseCase(userRepository user.Repository, inviteRepository invite.Repository, roles role.Repository, contentTypes contenttype.Repository, hasher hash.Hasher, mailRepository mail.Repository, publicURL string, recorder audit.Recorder) *CreateInviteUseCase {
	return &CreateInviteUseCase{userRepository, inviteRepository, roles, contentTypes, hasher, inviteMailer{mailRepository, publicURL}, recorder}
}

var inviteRoleRefusals = []error{role.ErrUnknownRole, role.ErrRoleLocked, role.ErrEscalation}

func isInviteRoleRefusal(err error) bool {
	for _, refusal := range inviteRoleRefusals {
		if errors.Is(err, refusal) {
			return true
		}
	}
	return false
}

func inviteRoleParams(event audit.Event, assigned role.Role) audit.Event {
	event.Params[audit.ParamRoleID] = assigned.ID
	event.Params[audit.ParamRole] = assigned.Name
	return event
}

func (g *CreateInviteUseCase) CreateInvite(ctx context.Context, command CreateInviteCommand) (InviteView, error) {
	event := audit.NewEvent(audit.ActionInviteCreate, audit.CategoryUsers)
	created, assigned, err := g.create(command)
	if err != nil {
		if !isInviteRoleRefusal(err) {
			recordFailure(ctx, g.recorder, event, err)
		}
		return InviteView{}, err
	}
	event.Target = inviteTarget(created)
	g.recorder.Record(ctx, inviteRoleParams(event, assigned))
	return InviteView{Invite: created, Role: NewRoleRef(assigned)}, nil
}

func (g *CreateInviteUseCase) assignedRole(command CreateInviteCommand) (role.Role, error) {
	if command.RoleID == 0 {
		return builtInRole(g.roles, role.WriterName)
	}
	return assignableRole(g.roles, command.RoleID)
}

func (g *CreateInviteUseCase) grantableRole(command CreateInviteCommand) (role.Role, error) {
	assigned, err := g.assignedRole(command)
	if err != nil {
		return role.Role{}, err
	}
	if err := ensureCovered(command.Caller, g.contentTypes, assigned); err != nil {
		return role.Role{}, err
	}
	return assigned, nil
}

func (g *CreateInviteUseCase) create(command CreateInviteCommand) (invite.Invite, role.Role, error) {
	email := strings.ToLower(command.Email)
	now := time.Now()

	inviter, err := g.userRepository.Get(command.InvitedBy)
	if err != nil {
		return invite.Invite{}, role.Role{}, err
	}

	assigned, err := g.grantableRole(command)
	if err != nil {
		return invite.Invite{}, role.Role{}, err
	}

	if g.emailHasAccount(email) {
		return invite.Invite{}, role.Role{}, invite.ErrEmailHasAccount
	}

	if err := g.discardOpenInvite(email, now); err != nil {
		return invite.Invite{}, role.Role{}, err
	}

	rawCode, hashedCode, err := newInviteCode(g.hasher)
	if err != nil {
		return invite.Invite{}, role.Role{}, err
	}

	createdInvite, err := g.inviteRepository.Create(invite.Invite{
		Email:      email,
		HashedCode: hashedCode,
		ExpiresAt:  now.Add(invite.Lifetime),
		InvitedBy:  command.InvitedBy,
		RoleID:     assigned.ID,
		CreatedAt:  now,
	})
	if err != nil {
		return invite.Invite{}, role.Role{}, err
	}

	if sendErr := g.mailer.send(email, rawCode, inviter); sendErr != nil {
		if deleteErr := g.inviteRepository.Delete(createdInvite.ID); deleteErr != nil {
			return invite.Invite{}, role.Role{}, errors.Join(sendErr, deleteErr)
		}
		return invite.Invite{}, role.Role{}, sendErr
	}

	return createdInvite, assigned, nil
}

func (g *CreateInviteUseCase) emailHasAccount(email string) bool {
	for _, existingUser := range g.userRepository.GetAll() {
		if strings.EqualFold(existingUser.Email, email) {
			return true
		}
	}
	return false
}

func (g *CreateInviteUseCase) discardOpenInvite(email string, now time.Time) error {
	for _, existing := range g.inviteRepository.GetAll() {
		if existing.Email != email {
			continue
		}
		switch existing.StatusAt(now) {
		case invite.StatusPending:
			return invite.ErrPendingInvite
		case invite.StatusExpired:
			if err := g.inviteRepository.Delete(existing.ID); err != nil {
				return err
			}
		}
	}
	return nil
}