-- ============================================================
-- Phase 4 数据库迁移脚本
-- 执行方式: psql -U postgres -d crm_erp -f migration_phase4.sql
-- ============================================================

-- ────── 1. pg_trgm 扩展（客户模糊搜索） ──────
CREATE EXTENSION IF NOT EXISTS pg_trgm;

-- 为客户名称建 pg_trgm GIN 索引
CREATE INDEX IF NOT EXISTS idx_cust_name_trgm
    ON crm_customers USING gin (name gin_trgm_ops);

-- ────── 2. 销项发票表 finance_sales_invoices ──────
CREATE TABLE IF NOT EXISTS finance_sales_invoices (
    id                   UUID PRIMARY KEY DEFAULT uuid_generate_v4(),
    issuer               VARCHAR(200) NOT NULL,                      -- 开票方/我方主体
    receiver_customer_id UUID NOT NULL REFERENCES crm_customers(id), -- 受票方
    invoice_number       VARCHAR(100) NOT NULL UNIQUE,               -- 发票号
    amount               NUMERIC(14,2) NOT NULL DEFAULT 0,           -- 票面金额
    billing_date         DATE NOT NULL,                              -- 开票时间
    payment_status       VARCHAR(20) NOT NULL DEFAULT '未回款'
        CHECK (payment_status IN ('未回款', '部分回款', '已结清')),
    payment_date         DATE,                                       -- 回款时间
    payment_amount       NUMERIC(14,2) DEFAULT 0,                    -- 已回款金额
    remark               TEXT,
    created_by           UUID REFERENCES sys_users(id),
    created_at           TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
    updated_at           TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
    is_deleted           BOOLEAN DEFAULT FALSE
);

COMMENT ON TABLE  finance_sales_invoices                       IS '销项发票表（AR 应收账款核心）';
COMMENT ON COLUMN finance_sales_invoices.issuer                IS '开票方/我方主体名称';
COMMENT ON COLUMN finance_sales_invoices.receiver_customer_id  IS '受票方，关联 crm_customers';
COMMENT ON COLUMN finance_sales_invoices.invoice_number        IS '发票号码（全局唯一）';
COMMENT ON COLUMN finance_sales_invoices.amount                IS '票面金额';
COMMENT ON COLUMN finance_sales_invoices.billing_date          IS '开票日期';
COMMENT ON COLUMN finance_sales_invoices.payment_status        IS '回款状态: 未回款/部分回款/已结清';
COMMENT ON COLUMN finance_sales_invoices.payment_date          IS '回款日期';
COMMENT ON COLUMN finance_sales_invoices.payment_amount        IS '已回款金额（用于部分回款场景）';

CREATE INDEX IF NOT EXISTS idx_fsi_receiver ON finance_sales_invoices(receiver_customer_id) WHERE is_deleted = FALSE;
CREATE INDEX IF NOT EXISTS idx_fsi_number ON finance_sales_invoices(invoice_number) WHERE is_deleted = FALSE;
CREATE INDEX IF NOT EXISTS idx_fsi_billing_date ON finance_sales_invoices(billing_date) WHERE is_deleted = FALSE;
CREATE INDEX IF NOT EXISTS idx_fsi_payment_status ON finance_sales_invoices(payment_status) WHERE is_deleted = FALSE;

CREATE TRIGGER trg_fsi_updated
    BEFORE UPDATE ON finance_sales_invoices
    FOR EACH ROW EXECUTE FUNCTION update_updated_at_column();

-- ────── 完成 ──────
-- 新增: finance_sales_invoices (1 张表)
-- 新增: pg_trgm 扩展 + crm_customers.name GIN 索引