#!/usr/bin/env python3
# -*- coding: utf-8 -*-
"""json2ddl 等价实现（ocai database-table-definition-spec）：
读取 models/{module}/*.json（summary/fields/indexes/codes），生成幂等 MySQL/MariaDB DDL。
幂等性：CREATE TABLE IF NOT EXISTS；索引先查 information_schema 再按需补建（可重跑）。
用法：python3 scripts/json2ddl.py <models根目录> [输出sql文件]
"""
import json, os, sys, glob

TYPE_MAP = {
    "varchar": lambda f: f"VARCHAR({f.get('length', 64)})",
    "text": lambda f: "TEXT",
    "int": lambda f: "INT",
    "date": lambda f: "DATE",
    "timestamp": lambda f: "TIMESTAMP NULL DEFAULT NULL",
    "decimal": lambda f: f"DECIMAL({f.get('precision', 18)},{f.get('scale', 4)})",
}

def render_field(f):
    t = f["type"]
    if t not in TYPE_MAP:
        raise ValueError(f"未知字段类型 {t} ({f.get('name')})")
    col = f"`{f['name']}` {TYPE_MAP[t](f)}"
    if f.get("notnull"):
        col += " NOT NULL"
    if "default" in f and t != "timestamp":
        dv = f["default"]
        col += f" DEFAULT '{dv}'" if isinstance(dv, str) else f" DEFAULT {dv}"
    col += f" COMMENT '{f['title']}'"
    return col

def render_index_sql(table, idx):
    kind = "UNIQUE KEY" if idx.get("unique") else "KEY"
    cols = ",".join(f"`{c}`" for c in idx["fields"])
    return f"  {kind} `{idx['name']}` ({cols})"

def gen_table_ddl(path):
    doc = json.load(open(path, encoding="utf-8"))
    s = doc["summary"][0]
    table = s["name"]
    lines = [render_field(f) for f in doc["fields"]]
    pk = ",".join(f"`{c}`" for c in s.get("pk", ["id"]))
    lines.append(f"  PRIMARY KEY ({pk})")
    for idx in doc.get("indexes", []):
        lines.append(render_index_sql(table, idx))
    charset = s.get("charset", "utf8mb4")
    collate = s.get("collate", "utf8mb4_unicode_ci")
    title = s.get("title", table)
    return table, (f"CREATE TABLE IF NOT EXISTS `{table}` (\n" + ",\n".join(lines) +
                   f"\n) ENGINE=InnoDB DEFAULT CHARSET={charset} COLLATE={collate} COMMENT='{title}';")

def gen_index_guard_sql(table, idx):
    """运行时补索引（建表时已含；此处供重跑补漏，apply_ddl.py 使用）"""
    kind = "UNIQUE INDEX" if idx.get("unique") else "INDEX"
    cols = ",".join(f"`{c}`" for c in idx["fields"])
    return f"ALTER TABLE `{table}` ADD {kind} `{idx['name']}` ({cols});"

def main():
    src = sys.argv[1] if len(sys.argv) > 1 else "models"
    out = sys.argv[2] if len(sys.argv) > 2 else None
    parts = ["-- 人事系统 hr-web 批次1 DDL（json2ddl 生成，幂等可重跑）",
             "-- 来源：models/*.json（database-design.md v3.0，49 表）；目标库：hrs(MariaDB)",
             "-- 执行：mysql -utest -ptest123 hrs < mysql.ddl.sql  或 python3 scripts/apply_ddl.py",
             "SET NAMES utf8mb4;", ""]
    n = 0
    for moddir in sorted(glob.glob(os.path.join(src, "*"))):
        if not os.path.isdir(moddir):
            continue
        files = sorted(glob.glob(os.path.join(moddir, "*.json")))
        if not files:
            continue
        parts.append(f"-- ===== {os.path.basename(moddir)}（{len(files)} 张）=====")
        for p in files:
            table, ddl = gen_table_ddl(p)
            parts.append(f"-- {table}")
            parts.append(ddl)
            parts.append("")
            n += 1
    parts.append(f"-- 共 {n} 张表")
    sql = "\n".join(parts) + "\n"
    if out:
        with open(out, "w", encoding="utf-8") as f:
            f.write(sql)
        print(f"生成 {out}：{n} 张表")
    else:
        sys.stdout.write(sql)

if __name__ == "__main__":
    main()