"""为育种核心表补「部分唯一索引（未软删）」并发兜底，幂等，可 --check 预览。

背景：combination_code / tree_no / cultivar_name / personnel.name / (site_id, plot_code)
无 DB 层唯一约束，service 层 select-then-insert 存在并发竞态。此处补部分唯一索引
（WHERE is_deleted = false），与各 service 的查重语义（只查未软删）一致：
- 未软删记录之间不允许重复 → 并发插入同一编号仅一条成功，另一条 409。
- 已软删记录不参与约束 → 删除后仍可重新使用该编号。

用法（backend/ 目录）：
    python scripts/add_unique_constraints.py --check
    python scripts/add_unique_constraints.py
"""
import argparse
import os
import sys

BACKEND_DIR = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
if BACKEND_DIR not in sys.path:
    sys.path.insert(0, BACKEND_DIR)

from sqlalchemy import create_engine, text

from app.config.setting import settings

# (表, 索引名, 唯一列, 说明)
UNIQUE_INDEXES = [
    ("bre_cross_combination", "uniq_bre_cross_combination_code", "combination_code", "组合编号"),
    ("bre_tree", "uniq_bre_tree_no", "tree_no", "单株编号"),
    ("bre_germplasm", "uniq_bre_germplasm_cultivar_name", "cultivar_name", "品种/种质名称"),
    ("bre_personnel", "uniq_bre_personnel_name", "name", "人员姓名"),
    ("bre_plot", "uniq_bre_plot_site_code", "site_id, plot_code", "基地地块编号"),
]


def main() -> None:
    parser = argparse.ArgumentParser(description="为育种表补部分唯一索引（未软删）")
    parser.add_argument("--check", action="store_true", help="仅打印将执行的 DDL，不落库")
    args = parser.parse_args()

    engine = create_engine(settings.DB_URI)
    print(f"# 连接: {settings.DB_URI}")

    with engine.connect() as conn:
        for table, idx_name, cols, label in UNIQUE_INDEXES:
            # 1) 未软删重复检查（部分索引只约束未软删行，故只查未软删）
            dup_sql = (
                f"SELECT {cols} FROM {table} "
                "WHERE is_deleted = false "
                f"GROUP BY {cols} HAVING COUNT(*) > 1"
            )
            try:
                dups = conn.execute(text(dup_sql)).fetchall()
            except Exception as e:
                print(f"# [跳过] {table}: 查重失败 {e!s}")
                continue
            if dups:
                print(f"# [跳过] {label}（{table}.{cols}）存在 {len(dups)} 组未软删重复，请先清洗数据:")
                for d in dups[:10]:
                    print("        " + " / ".join(str(x) for x in d))
                continue

            # 2) 索引是否已存在
            exists = conn.execute(
                text("SELECT 1 FROM pg_indexes WHERE indexname = :name"),
                {"name": idx_name},
            ).fetchone()
            if exists:
                print(f"# [已存在] {idx_name}")
                continue

            ddl = (
                f"CREATE UNIQUE INDEX {idx_name} ON {table} ({cols}) "
                "WHERE is_deleted = false"
            )
            print("  " + ddl)
            if not args.check:
                try:
                    with engine.begin() as c:
                        c.execute(text(ddl))
                    print("OK  " + ddl)
                except Exception as e:
                    print("ERR " + ddl + " -> " + str(e)[:160])

    print("# --check 模式：未执行任何变更。" if args.check else "# 完成。")


if __name__ == "__main__":
    main()