// 新加坡（SG）辖区适配器
// 法律体系：普通法系
// 主要法律：《土地所有权法》《印花税法》《公司法》《证券期货法》《支付服务法》

use crate::{
    AssetCategorySupport, AssetTransferTaxSummary, DisputeResolutionPreference,
    ForeignInvestmentRestrictions, JurisdictionAdapter, RealEstateRegistrationReq,
    RegulatoryBody, ValidationResult,
};
use nac_rwa_legal_model::{AssetCategory, LegalSystem, RealEstateSubtype};

pub struct SgAdapter;

impl JurisdictionAdapter for SgAdapter {
    fn jurisdiction_code(&self) -> &'static str { "SG" }
    fn jurisdiction_name(&self) -> &'static str { "新加坡共和国" }
    fn legal_system(&self) -> LegalSystem { LegalSystem::CommonLaw }

    fn supported_asset_categories(&self) -> Vec<AssetCategorySupport> {
        vec![
            AssetCategorySupport {
                category: "不动产（商业/工业）".to_string(),
                supported: true,
                foreign_entity_allowed: true,
                restrictions: Some("外资可购买商业/工业不动产，住宅受限".to_string()),
                required_approvals: vec!["新加坡土地管理局（SLA）".to_string()],
            },
            AssetCategorySupport {
                category: "不动产（住宅公寓）".to_string(),
                supported: true,
                foreign_entity_allowed: true,
                restrictions: Some("外资可购买私人公寓，但须缴纳ABSD 60%（2023年起）".to_string()),
                required_approvals: vec!["新加坡土地管理局（SLA）".to_string()],
            },
            AssetCategorySupport {
                category: "数字代币（证券型）".to_string(),
                supported: true,
                foreign_entity_allowed: true,
                restrictions: Some("须持有MAS颁发的资本市场服务（CMS）牌照".to_string()),
                required_approvals: vec!["新加坡金融管理局（MAS）".to_string()],
            },
        ]
    }

    fn real_estate_registration_requirements(&self) -> RealEstateRegistrationReq {
        RealEstateRegistrationReq {
            registry_authority: "新加坡土地管理局（Singapore Land Authority, SLA）".to_string(),
            notarization_required: false,
            notary_authority: None,
            registration_process: "签订买卖协议（OTP/S&P）→ 缴纳印花税（14天内）→ 完成交割 → 在SLA完成产权转移登记（Caveat/Transfer）".to_string(),
            foreign_buyer_restrictions: Some("外资购买住宅须缴纳ABSD 60%（2023年4月起）；购买有地住宅须获得土地管理局批准".to_string()),
            required_documents: vec![
                "购房意向书（OTP）或买卖合约（S&P）".to_string(),
                "护照/身份证".to_string(),
                "印花税缴纳证明（IRAS）".to_string(),
                "按揭批准函（如适用）".to_string(),
                "律师行转让文件".to_string(),
            ],
            typical_completion_days: 90,
            registration_fee_pct: 0.001,
        }
    }

    fn foreign_investment_restrictions(&self) -> ForeignInvestmentRestrictions {
        ForeignInvestmentRestrictions {
            has_fdi_review: false,
            review_authority: None,
            prohibited_sectors: vec![],
            restricted_sectors: vec![
                "有地住宅（须土地管理局批准）".to_string(),
                "媒体（须持牌）".to_string(),
            ],
            real_estate_restrictions: Some("外资购买住宅须缴纳ABSD 60%；有地住宅须获专项批准".to_string()),
            legal_basis: "《住宅物业法》（Residential Property Act）".to_string(),
        }
    }

    fn regulatory_bodies(&self) -> Vec<RegulatoryBody> {
        vec![
            RegulatoryBody {
                name: "新加坡金融管理局".to_string(),
                abbreviation: "MAS".to_string(),
                jurisdiction_area: "金融监管、数字资产、支付服务".to_string(),
                website: Some("https://www.mas.gov.sg".to_string()),
            },
            RegulatoryBody {
                name: "新加坡土地管理局".to_string(),
                abbreviation: "SLA".to_string(),
                jurisdiction_area: "不动产登记、土地管理".to_string(),
                website: Some("https://www.sla.gov.sg".to_string()),
            },
            RegulatoryBody {
                name: "新加坡税务局".to_string(),
                abbreviation: "IRAS".to_string(),
                jurisdiction_area: "税收征管".to_string(),
                website: Some("https://www.iras.gov.sg".to_string()),
            },
        ]
    }

    fn asset_transfer_tax_summary(&self) -> AssetTransferTaxSummary {
        AssetTransferTaxSummary {
            real_estate_transfer_tax_buyer: Some(0.04), // BSD 最高 4%
            real_estate_transfer_tax_seller: None,
            stamp_duty: Some(0.60), // ABSD 外资 60%
            capital_gains_tax_resident: None, // 新加坡无资本利得税
            capital_gains_tax_nonresident: None,
            vat_or_gst: Some(0.09), // GST 9%（2024年起）
            withholding_tax_dividend: None, // 无股息预提税
            withholding_tax_interest: Some(0.15),
            withholding_tax_royalty: Some(0.10),
            notes: Some("外资买家ABSD 60%（2023年4月起）；新加坡无资本利得税；GST 9%适用于商业交易".to_string()),
        }
    }

    fn preferred_dispute_resolution(&self) -> DisputeResolutionPreference {
        DisputeResolutionPreference {
            real_estate: "新加坡高等法院".to_string(),
            goods_trade: "新加坡国际仲裁中心（SIAC）".to_string(),
            intellectual_property: "新加坡知识产权法院/SIAC".to_string(),
            financial: "SIAC/新加坡高等法院".to_string(),
            new_york_convention_member: true,
        }
    }

    fn validate_asset_for_tokenization(
        &self,
        asset: &AssetCategory,
        is_foreign_entity: bool,
    ) -> ValidationResult {
        match asset {
            AssetCategory::RealEstate(subtype) => {
                if is_foreign_entity {
                    match subtype {
                        RealEstateSubtype::Residential => {
                            ValidationResult::ApprovedWithConditions(vec![
                                "须缴纳ABSD 60%（外资买家）".to_string(),
                                "有地住宅须获土地管理局专项批准".to_string(),
                            ])
                        }
                        _ => ValidationResult::ApprovedWithConditions(vec![
                            "商业/工业不动产外资可自由购买".to_string(),
                            "须在SLA完成产权登记".to_string(),
                        ]),
                    }
                } else {
                    ValidationResult::ApprovedWithConditions(vec![
                        "须缴纳BSD印花税".to_string(),
                        "须在SLA完成产权登记".to_string(),
                    ])
                }
            }
            _ => ValidationResult::Approved,
        }
    }
}