package adminuser

import (
	"context"
	"errors"
	"regexp"
	"strings"
)

var (
	ErrDependencyUnavailable   = errors.New("dependency unavailable")
	ErrInvalidUser             = errors.New("invalid user")
	ErrInvalidRealnameInput    = errors.New("invalid realname input")
	ErrRealnameAlreadyVerified = errors.New("realname already verified")
	ErrRealnameNotRevocable    = errors.New("realname not revocable")
	ErrInvalidWalletDirection  = errors.New("invalid wallet direction")
	ErrInvalidWalletAmount     = errors.New("invalid wallet amount")
	ErrInvalidWalletReason     = errors.New("invalid wallet reason")
	ErrInsufficientBalance     = errors.New("insufficient balance")
)

// 单笔人工调账上限：10 万元，防止误填。
const maxWalletAdjustAmountCent int64 = 10_000_000

var manualRealnameIDPattern = regexp.MustCompile(`^\d{17}[\dXx]$`)

type Service struct {
	repo *Repository
}

func NewService(repo *Repository) *Service {
	return &Service{repo: repo}
}

func (s *Service) List(ctx context.Context, page, pageSize int, query ListQuery) (*PaginatedResult, error) {
	if s.repo == nil {
		return nil, ErrDependencyUnavailable
	}
	return s.repo.List(ctx, page, pageSize, query)
}

func (s *Service) Freeze(ctx context.Context, adminID uint64, userID uint64, req FreezeRequest, meta AuditMeta) (*UserDTO, error) {
	if s.repo == nil {
		return nil, ErrDependencyUnavailable
	}
	if userID == 0 {
		return nil, ErrInvalidUser
	}
	return s.repo.Freeze(ctx, adminID, userID, req, meta)
}

func (s *Service) Unfreeze(ctx context.Context, adminID uint64, userID uint64, meta AuditMeta) (*UserDTO, error) {
	if s.repo == nil {
		return nil, ErrDependencyUnavailable
	}
	if userID == 0 {
		return nil, ErrInvalidUser
	}
	return s.repo.Unfreeze(ctx, adminID, userID, meta)
}

func (s *Service) SetDepositFreeQuota(ctx context.Context, adminID uint64, userID uint64, req DepositFreeQuotaRequest, meta AuditMeta) (*UserDTO, error) {
	if s.repo == nil {
		return nil, ErrDependencyUnavailable
	}
	if userID == 0 || req.AmountCent < 0 {
		return nil, ErrInvalidUser
	}
	return s.repo.SetDepositFreeQuota(ctx, adminID, userID, req, meta)
}

func (s *Service) RevokeRealname(ctx context.Context, adminID uint64, userID uint64, req RevokeRealnameRequest, meta AuditMeta) (*UserDTO, error) {
	if s.repo == nil {
		return nil, ErrDependencyUnavailable
	}
	if userID == 0 {
		return nil, ErrInvalidUser
	}
	return s.repo.RevokeRealname(ctx, adminID, userID, req, meta)
}

func (s *Service) ManualRealname(ctx context.Context, adminID uint64, userID uint64, req ManualRealnameRequest, meta AuditMeta) (*UserDTO, error) {
	if s.repo == nil {
		return nil, ErrDependencyUnavailable
	}
	if userID == 0 {
		return nil, ErrInvalidUser
	}
	if !validManualRealname(req.Name, req.IDNo) {
		return nil, ErrInvalidRealnameInput
	}
	return s.repo.ManualRealname(ctx, adminID, userID, req, meta)
}

func (s *Service) AdjustWallet(ctx context.Context, adminID uint64, userID uint64, req WalletAdjustRequest, meta AuditMeta) (*UserDTO, error) {
	if s.repo == nil {
		return nil, ErrDependencyUnavailable
	}
	if userID == 0 {
		return nil, ErrInvalidUser
	}
	direction := strings.TrimSpace(strings.ToLower(req.Direction))
	if direction != "in" && direction != "out" {
		return nil, ErrInvalidWalletDirection
	}
	if req.AmountCent <= 0 || req.AmountCent > maxWalletAdjustAmountCent {
		return nil, ErrInvalidWalletAmount
	}
	if reasonLen := len([]rune(strings.TrimSpace(req.Reason))); reasonLen < 2 || reasonLen > 200 {
		return nil, ErrInvalidWalletReason
	}
	req.Direction = direction
	req.Reason = strings.TrimSpace(req.Reason)
	req.ReferenceNo = strings.TrimSpace(req.ReferenceNo)
	return s.repo.AdjustWallet(ctx, adminID, userID, req, meta)
}

func validManualRealname(name string, idNo string) bool {
	name = strings.TrimSpace(name)
	idNo = strings.TrimSpace(idNo)
	nameLen := len([]rune(name))
	return nameLen >= 2 && nameLen <= 30 && manualRealnameIDPattern.MatchString(idNo)
}