package adminfinance

import (
	"context"
	"errors"
	"net/url"
	"strings"
	"unicode/utf8"

	"hfb_sys/backend/internal/auditlog"
)

var (
	ErrDependencyUnavailable      = errors.New("dependency unavailable")
	ErrInvalidManualDisbursement  = errors.New("invalid manual disbursement")
	ErrManualDisbursementNotFound = errors.New("manual disbursement not found")
	ErrManualDisbursementNotPaid  = errors.New("manual disbursement is not paid")
)

type Service struct {
	repo *Repository
}

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

func (s *Service) Dashboard(ctx context.Context, query DashboardQuery) (*DashboardDTO, error) {
	if s.repo == nil {
		return nil, ErrDependencyUnavailable
	}
	return s.repo.Dashboard(ctx, query)
}

func (s *Service) Details(ctx context.Context, query DetailQuery) (*PaginatedResult, error) {
	if s.repo == nil {
		return nil, ErrDependencyUnavailable
	}
	if query.Page < 1 {
		query.Page = 1
	}
	if query.PageSize < 1 {
		query.PageSize = 20
	}
	if query.PageSize > 100 {
		query.PageSize = 100
	}
	return s.repo.Details(ctx, query)
}

func (s *Service) Disbursements(ctx context.Context, query DisbursementQuery) (*DisbursementListDTO, error) {
	if s.repo == nil {
		return nil, ErrDependencyUnavailable
	}
	if query.Page < 1 {
		query.Page = 1
	}
	if query.PageSize < 1 {
		query.PageSize = 20
	}
	if query.PageSize > 100 {
		query.PageSize = 100
	}
	return s.repo.Disbursements(ctx, query)
}

func (s *Service) CreateManualDisbursement(
	ctx context.Context,
	req CreateManualDisbursementRequest,
	adminID uint64,
	meta auditlog.Meta,
) (*ManualDisbursementDTO, error) {
	if s.repo == nil {
		return nil, ErrDependencyUnavailable
	}
	req.Category = strings.TrimSpace(req.Category)
	req.CustomCategoryName = strings.TrimSpace(req.CustomCategoryName)
	req.PayeeName = strings.TrimSpace(req.PayeeName)
	req.Remark = strings.TrimSpace(req.Remark)
	req.VoucherURL = strings.TrimSpace(req.VoucherURL)
	if !validManualDisbursementCategory(req.Category) ||
		!validManualDisbursementCustomCategoryName(req.Category, req.CustomCategoryName) ||
		utf8.RuneCountInString(req.PayeeName) < 1 || utf8.RuneCountInString(req.PayeeName) > 100 ||
		req.AmountCent <= 0 || req.PaidAt.IsZero() ||
		utf8.RuneCountInString(req.Remark) < 1 || utf8.RuneCountInString(req.Remark) > 500 ||
		!validManualVoucherURL(req.VoucherURL) {
		return nil, ErrInvalidManualDisbursement
	}
	return s.repo.CreateManualDisbursement(ctx, req, adminID, meta)
}

func (s *Service) VoidManualDisbursement(
	ctx context.Context,
	id uint64,
	reason string,
	adminID uint64,
	meta auditlog.Meta,
) (*ManualDisbursementDTO, error) {
	if s.repo == nil {
		return nil, ErrDependencyUnavailable
	}
	reason = strings.TrimSpace(reason)
	if id == 0 || utf8.RuneCountInString(reason) < 1 || utf8.RuneCountInString(reason) > 255 {
		return nil, ErrInvalidManualDisbursement
	}
	return s.repo.VoidManualDisbursement(ctx, id, reason, adminID, meta)
}

func validManualDisbursementCategory(category string) bool {
	switch category {
	case "user_compensation", "seller_supplement", "operating_expense", "channel_fee", "duoduo_deposit_refund", "other", "custom":
		return true
	default:
		return false
	}
}

func validManualDisbursementCustomCategoryName(category, name string) bool {
	if category != "custom" {
		return name == ""
	}
	return utf8.RuneCountInString(name) >= 1 && utf8.RuneCountInString(name) <= 50
}

func validManualVoucherURL(raw string) bool {
	if raw == "" {
		return true
	}
	if len(raw) > 500 {
		return false
	}
	parsed, err := url.Parse(raw)
	if err != nil || parsed.IsAbs() || parsed.Path != "/api/files/object" {
		return false
	}
	return strings.HasPrefix(parsed.Query().Get("key"), "manual-disbursement/")
}