package usecase

import (
	"context"
	"strings"

	app "haixun-backend/internal/library/errors"
	"haixun-backend/internal/library/errors/code"
	authusecase "haixun-backend/internal/model/auth/domain/usecase"
	"haixun-backend/internal/model/member/domain/entity"
	domrepo "haixun-backend/internal/model/member/domain/repository"
	domusecase "haixun-backend/internal/model/member/domain/usecase"

	"github.com/google/uuid"
	"golang.org/x/crypto/bcrypt"
)

type memberUseCase struct {
	repo   domrepo.Repository
	tokens authusecase.TokenUseCase
}

func NewUseCase(repo domrepo.Repository, tokens authusecase.TokenUseCase) domusecase.UseCase {
	return &memberUseCase{repo: repo, tokens: tokens}
}

func (u *memberUseCase) Register(ctx context.Context, req domusecase.RegisterRequest) (*entity.Member, *domusecase.AuthToken, error) {
	tenantID := strings.TrimSpace(req.TenantID)
	email := normalizeEmail(req.Email)
	if tenantID == "" || email == "" || req.Password == "" {
		return nil, nil, app.For(code.Member).InputMissingRequired("tenant_id, email, and password are required")
	}
	if len(req.Password) < 8 {
		return nil, nil, app.For(code.Member).InputInvalidFormat("password must be at least 8 characters")
	}
	hash, err := bcrypt.GenerateFromPassword([]byte(req.Password), bcrypt.DefaultCost)
	if err != nil {
		return nil, nil, app.For(code.Member).SysInternal("hash password failed").WithCause(err)
	}
	member, err := u.repo.Create(ctx, &entity.Member{
		TenantID:     tenantID,
		UID:          uuid.NewString(),
		Email:        email,
		DisplayName:  strings.TrimSpace(req.DisplayName),
		Language:     strings.TrimSpace(req.Language),
		Status:       entity.StatusOpen,
		Origin:       entity.OriginNative,
		PasswordHash: string(hash),
		Roles:        []string{"user"},
	})
	if err != nil {
		return nil, nil, err
	}
	token, err := u.issue(ctx, member)
	return member, token, err
}

func (u *memberUseCase) Login(ctx context.Context, req domusecase.LoginRequest) (*entity.Member, *domusecase.AuthToken, error) {
	tenantID := strings.TrimSpace(req.TenantID)
	email := normalizeEmail(req.Email)
	if tenantID == "" || email == "" || req.Password == "" {
		return nil, nil, app.For(code.Auth).InputMissingRequired("tenant_id, email, and password are required")
	}
	member, err := u.repo.FindByEmail(ctx, tenantID, email)
	if err != nil {
		return nil, nil, app.For(code.Auth).AuthUnauthorized("invalid email or password").WithCause(err)
	}
	if member.Status != entity.StatusOpen {
		return nil, nil, app.For(code.Auth).AuthForbidden("member is not active")
	}
	if err := bcrypt.CompareHashAndPassword([]byte(member.PasswordHash), []byte(req.Password)); err != nil {
		return nil, nil, app.For(code.Auth).AuthUnauthorized("invalid email or password")
	}
	token, err := u.issue(ctx, member)
	return member, token, err
}

func (u *memberUseCase) ListMembers(ctx context.Context, req domusecase.ListMembersRequest) (*domusecase.ListMembersResult, error) {
	if strings.TrimSpace(req.TenantID) == "" {
		return nil, app.For(code.Member).InputMissingRequired("tenant_id is required")
	}
	items, total, page, pageSize, err := u.repo.List(ctx, strings.TrimSpace(req.TenantID), req.Page, req.PageSize)
	if err != nil {
		return nil, err
	}
	totalPages := int64(0)
	if pageSize > 0 {
		totalPages = (total + pageSize - 1) / pageSize
	}
	return &domusecase.ListMembersResult{List: items, Total: total, Page: page, PageSize: pageSize, TotalPages: totalPages}, nil
}

func (u *memberUseCase) GetByUID(ctx context.Context, tenantID, uid string) (*entity.Member, error) {
	if tenantID == "" || uid == "" {
		return nil, app.For(code.Member).InputMissingRequired("tenant_id and uid are required")
	}
	return u.repo.FindByUID(ctx, tenantID, uid)
}

func (u *memberUseCase) SetActiveThreadsAccountID(ctx context.Context, tenantID, uid, accountID string) error {
	if tenantID == "" || uid == "" {
		return app.For(code.Member).InputMissingRequired("tenant_id and uid are required")
	}
	return u.repo.SetActiveThreadsAccountID(ctx, tenantID, uid, accountID)
}

func (u *memberUseCase) SetRoles(ctx context.Context, tenantID, uid string, roles []string) error {
	if tenantID == "" || uid == "" {
		return app.For(code.Member).InputMissingRequired("tenant_id and uid are required")
	}
	normalized := normalizeRoles(roles)
	if len(normalized) == 0 {
		return app.For(code.Member).InputInvalidFormat("roles must include user or admin")
	}
	for _, role := range normalized {
		if role != "user" && role != "admin" {
			return app.For(code.Member).InputInvalidFormat("roles only support user or admin")
		}
	}
	return u.repo.SetRoles(ctx, tenantID, uid, normalized)
}

func (u *memberUseCase) SetEmailVerificationCode(ctx context.Context, tenantID, uid, verifyCode string, expiresAt int64) error {
	if tenantID == "" || uid == "" || strings.TrimSpace(verifyCode) == "" || expiresAt <= 0 {
		return app.For(code.Member).InputMissingRequired("tenant_id, uid, code, and expires_at are required")
	}
	return u.repo.SetEmailVerificationCode(ctx, tenantID, uid, strings.TrimSpace(verifyCode), expiresAt)
}

func (u *memberUseCase) UpdatePassword(ctx context.Context, tenantID, uid, password string) error {
	if tenantID == "" || uid == "" || password == "" {
		return app.For(code.Member).InputMissingRequired("tenant_id, uid, and password are required")
	}
	if len(password) < 8 {
		return app.For(code.Member).InputInvalidFormat("password must be at least 8 characters")
	}
	hash, err := bcrypt.GenerateFromPassword([]byte(password), bcrypt.DefaultCost)
	if err != nil {
		return app.For(code.Member).SysInternal("hash password failed").WithCause(err)
	}
	return u.repo.UpdatePassword(ctx, tenantID, uid, string(hash))
}

func (u *memberUseCase) UpdateProfile(ctx context.Context, req domusecase.UpdateProfileRequest) (*entity.Member, error) {
	if req.TenantID == "" || req.UID == "" {
		return nil, app.For(code.Member).InputMissingRequired("tenant_id and uid are required")
	}
	var status *entity.Status
	if req.Status != nil {
		next := entity.Status(strings.TrimSpace(*req.Status))
		if next != entity.StatusOpen && next != entity.StatusSuspended && next != entity.StatusDeleted {
			return nil, app.For(code.Member).InputInvalidFormat("status only supports open, suspended, or deleted")
		}
		status = &next
	}
	return u.repo.UpdateProfile(ctx, req.TenantID, req.UID, domrepo.ProfileUpdate{
		DisplayName:           req.DisplayName,
		Avatar:                req.Avatar,
		Language:              req.Language,
		Currency:              req.Currency,
		Phone:                 req.Phone,
		EmailVerified:         req.EmailVerified,
		Status:                status,
		BusinessEmail:         req.BusinessEmail,
		BusinessEmailVerified: req.BusinessEmailVerified,
		BusinessPhone:         req.BusinessPhone,
		BusinessPhoneVerified: req.BusinessPhoneVerified,
	})
}

func (u *memberUseCase) issue(ctx context.Context, member *entity.Member) (*domusecase.AuthToken, error) {
	if u.tokens == nil {
		return nil, app.For(code.Auth).SysNotImplemented("token usecase is not configured")
	}
	pair, err := u.tokens.IssuePair(ctx, authusecase.IssuePairRequest{
		TenantID: member.TenantID,
		UID:      member.UID,
	})
	if err != nil {
		return nil, err
	}
	return &domusecase.AuthToken{
		AccessToken:  pair.AccessToken,
		RefreshToken: pair.RefreshToken,
		ExpiresIn:    pair.ExpiresIn,
		UID:          member.UID,
		TokenType:    pair.TokenType,
	}, nil
}

func normalizeEmail(email string) string {
	return strings.ToLower(strings.TrimSpace(email))
}

func normalizeRoles(roles []string) []string {
	seen := make(map[string]bool, len(roles))
	out := make([]string, 0, len(roles))
	for _, role := range roles {
		role = strings.ToLower(strings.TrimSpace(role))
		if role == "" || seen[role] {
			continue
		}
		seen[role] = true
		out = append(out, role)
	}
	return out
}