#!/usr/bin/env python3
"""Deterministic generator of the askmdb-test databases, from the declarative specs in specs/.

Same spec + same seed -> same documents, same _id and same dbHash. The test uses seed 0.
Requires Python >= 3.9 and pymongo (tested with pymongo 4.19 and MongoDB 8.0).

    python3 tools/gen.py --uri mongodb://localhost:27017            # load the 10 databases, check dbHash
    python3 tools/gen.py --uri mongodb://localhost:27017 --only crm-02

WARNING: each database named in a spec ("db") is dropped and recreated. Use a throwaway server.
Every value is invented: names, cities and words come from the fixed lists below, emails use the
reserved example.com/.org/.net domains, and phone-like strings are random digits.
"""

import argparse
import datetime as dt
import json
import random
import re
import struct
import sys
import unicodedata
from decimal import Decimal
from pathlib import Path

import pymongo
from bson import Decimal128, Int64, ObjectId

HERE = Path(__file__).resolve().parent.parent
SEED = 0
INSERT_BATCH = 1000

DEFAULT_GEN = {
    "str": {"kind": "words", "n": [1, 3]},
    "int": {"kind": "int_range", "min": 0, "max": 100},
    "long": {"kind": "int_range", "min": 1_000_000_000, "max": 1_000_000_000_000},
    "double": {"kind": "lognormal", "mu": 3, "sigma": 1, "round": 2},
    "decimal": {"kind": "lognormal", "mu": 4, "sigma": 1, "round": 2},
    "bool": {"kind": "enum", "values": [True, False]},
    "date": {"kind": "date_back", "days": 365},
    "oid": {"kind": "oid"},
}


FIRST = {
    "es": ["Lucía", "Martín", "Sofía", "Hugo", "Paula", "Daniel", "Carmen", "Pablo", "Elena", "Javier",
           "Marta", "Diego", "Laura", "Álvaro", "Irene", "Sergio", "Nuria", "Raúl", "Alba", "Iván",
           "Rocío", "Andrés", "Clara", "Jorge", "Inés", "Rubén", "Noelia", "Óscar", "Pilar", "Tomás"],
    "en": ["Emma", "Liam", "Olivia", "Noah", "Ava", "Ethan", "Mia", "Lucas", "Grace", "Owen",
           "Chloe", "Henry", "Ella", "Jack", "Ruby", "Leo", "Alice", "Oscar", "Lily", "Adam",
           "Isla", "Ryan", "Zoe", "Nathan", "Hannah", "Caleb", "Maya", "Isaac", "Sarah", "Dylan"],
}


LAST = {
    "es": ["García", "Fernández", "López", "Martínez", "Sánchez", "Pérez", "Gómez", "Ruiz", "Díaz", "Moreno",
           "Muñoz", "Álvarez", "Romero", "Navarro", "Torres", "Domínguez", "Vázquez", "Ramos", "Gil", "Serrano",
           "Molina", "Blanco", "Suárez", "Castro", "Ortega", "Delgado", "Ortiz", "Marín", "Rubio", "Iglesias"],
    "en": ["Smith", "Johnson", "Brown", "Taylor", "Wilson", "Davies", "Evans", "Thomas", "Walker", "White",
           "Harris", "Martin", "Thompson", "Wood", "Clarke", "Hall", "Wright", "Green", "Baker", "Turner",
           "Hill", "Cooper", "Ward", "Morris", "King", "Moore", "Parker", "Bennett", "Carter", "Hughes"],
}


CITY = {
    "es": ["Madrid", "Barcelona", "Valencia", "Sevilla", "Zaragoza", "Málaga", "Murcia", "Bilbao",
           "Alicante", "Córdoba", "Valladolid", "Vigo", "Gijón", "Granada", "Oviedo", "Pamplona",
           "Santander", "Salamanca", "Burgos", "Cádiz"],
    "en": ["London", "Manchester", "Leeds", "Bristol", "Liverpool", "Glasgow", "Dublin", "Boston",
           "Denver", "Seattle", "Austin", "Portland", "Chicago", "Toronto", "Sydney", "Auckland",
           "Cardiff", "Belfast", "Phoenix", "Oxford"],
}


WORDS = {
    "es": ["revisión", "pedido", "rápido", "cliente", "nuevo", "urgente", "pendiente", "material",
           "entrega", "precio", "calidad", "servicio", "retraso", "factura", "llamada", "correo",
           "problema", "solución", "cambio", "producto", "equipo", "mañana", "tarde", "semana",
           "grande", "pequeño", "rojo", "azul", "verde", "blanco", "negro", "nota", "aviso",
           "consulta", "reparación", "garantía", "devolución", "oferta", "descuento", "stock",
           "almacén", "proveedor", "contrato", "cita", "informe", "resumen", "detalle", "medida",
           "básico", "premium", "estándar", "especial", "local", "nacional", "online", "tienda",
           "caja", "paquete", "lote", "unidad", "precioso", "limpio", "roto", "usado"],
    "en": ["review", "order", "quick", "customer", "new", "urgent", "pending", "material",
           "delivery", "price", "quality", "service", "delay", "invoice", "call", "email",
           "issue", "fix", "change", "product", "team", "morning", "evening", "week",
           "large", "small", "red", "blue", "green", "white", "black", "note", "notice",
           "question", "repair", "warranty", "return", "offer", "discount", "stock",
           "warehouse", "supplier", "contract", "booking", "report", "summary", "detail", "size",
           "basic", "premium", "standard", "special", "local", "national", "online", "store",
           "box", "parcel", "batch", "unit", "lovely", "clean", "broken", "used"],
}


EMAIL_DOMAINS = ["example.com", "example.org", "example.net"]


class SpecError(Exception):
    pass


def parse_ref_date(spec):
    return dt.datetime.strptime(spec["ref_date"], "%Y-%m-%dT%H:%M:%SZ").replace(tzinfo=dt.timezone.utc)


def field_name(path):
    return path[:-2] if path.endswith("[]") else path


def iter_fields(fields):
    """Every field dict, nested ones included (obj fields, array element fields)."""
    for f in fields:
        yield f
        if f.get("type") == "obj":
            yield from iter_fields(f.get("fields") or [])
        elif f.get("type") == "array":
            of = f.get("of") or {}
            yield of
            if of.get("type") == "obj":
                yield from iter_fields(of.get("fields") or [])


def _num(x):
    return isinstance(x, (int, float)) and not isinstance(x, bool)


def _ref_order(spec):
    """Collection names in generation order (ref targets first); raises SpecError on cycles."""
    colls = [c["name"] for c in spec["collections"]]
    deps = {c["name"]: set() for c in spec["collections"]}
    for c in spec["collections"]:
        for f in iter_fields(c.get("fields") or []):
            if f.get("type") == "ref" and isinstance(f.get("to"), str):
                deps[c["name"]].add(f["to"].split(".", 1)[0])
    order, done = [], set()
    while len(order) < len(colls):
        ready = [n for n in colls if n not in done and deps[n] <= done]
        if not ready:
            raise SpecError("refs form a cycle (or a collection refers to itself)")
        order.append(ready[0])
        done.add(ready[0])
    return order


def _parse_date(s):
    if not isinstance(s, str):
        raise TypeError("date must be a string")
    fmt = "%Y-%m-%d" if len(s) == 10 else "%Y-%m-%dT%H:%M:%SZ"
    return dt.datetime.strptime(s, fmt).replace(tzinfo=dt.timezone.utc)


def _ascii(s):
    return unicodedata.normalize("NFKD", s).encode("ascii", "ignore").decode().lower()


class _Ctx:
    def __init__(self, spec, rng, targets):
        self.rng = rng
        self.ref_date = parse_ref_date(spec)
        self.names = spec["names"]
        self.targets = targets          # {"coll.field": [values]}
        self.seq = {}                   # id(gen) -> next index
        self.cum = {}                   # id(obj) -> cumulative weights

    def lang(self, g):
        lang = g.get("lang", self.names)
        return self.rng.choice(("es", "en")) if lang == "mix" else lang


def _rounded(v, g):
    if "round" in g:
        v = round(v, g["round"])
        if g["round"] == 0:
            v = int(v)
    return v


def _clip(v, g):
    if "min" in g:
        v = max(v, g["min"])
    if "max" in g:
        v = min(v, g["max"])
    return v


def run_gen(g, ctx):
    rng = ctx.rng
    kind = g["kind"]
    if kind == "enum":
        vals = g["values"]
        w = g.get("weights")
        if w is None:
            return vals[rng.randrange(len(vals))]
        cum = ctx.cum.get(id(g))
        if cum is None:
            cum = ctx.cum[id(g)] = list(_accumulate(w))
        return rng.choices(vals, cum_weights=cum)[0]
    if kind == "int_range":
        return rng.randint(int(g["min"]), int(g["max"]))
    if kind == "float_range":
        return _rounded(rng.uniform(g["min"], g["max"]), g)
    if kind == "normal":
        return _rounded(_clip(rng.gauss(g["mu"], g["sigma"]), g), g)
    if kind == "lognormal":
        return _rounded(_clip(rng.lognormvariate(g["mu"], g["sigma"]), g), g)
    if kind == "date_back":
        lo = -g["days"] * 86400
        hi = g.get("ahead", 0) * 86400
        d = ctx.ref_date + dt.timedelta(seconds=rng.randint(lo, hi))
        return _day(d) if g.get("time", True) is False else d
    if kind == "date_range":
        a, b = _parse_date(g["from"]), _parse_date(g["to"])
        d = a + dt.timedelta(seconds=rng.randint(0, int((b - a).total_seconds())))
        return _day(d) if g.get("time", True) is False else d
    if kind == "pattern":
        out = []
        for ch in g["fmt"]:
            if ch == "#":
                out.append(str(rng.randrange(10)))
            elif ch == "?":
                out.append(chr(65 + rng.randrange(26)))
            else:
                out.append(ch)
        return "".join(out)
    if kind == "words":
        lo, hi = g.get("n", [1, 3])
        lang = ctx.lang(g)
        return " ".join(rng.choice(WORDS[lang]) for _ in range(rng.randint(lo, hi)))
    if kind == "person":
        lang = ctx.lang(g)
        part = g.get("part", "full")
        first, last = rng.choice(FIRST[lang]), rng.choice(LAST[lang])
        return first if part == "first" else last if part == "last" else f"{first} {last}"
    if kind == "seq":
        i = ctx.seq.get(id(g), 0)
        ctx.seq[id(g)] = i + 1
        n = g.get("start", 1) + g.get("step", 1) * i
        if "prefix" in g or "width" in g:
            return f"{g.get('prefix', '')}{n:0{g.get('width', 1)}d}"
        return n
    if kind == "city":
        lang = g.get("lang", ctx.names)
        both = [x for pair in zip(CITY["es"], CITY["en"]) for x in pair]
        cities = (both if lang == "mix" else CITY[lang])[: g.get("n", 8)]
        cum = ctx.cum.get(id(g))
        if cum is None:  # long tail: weight 1/(rank+1)
            cum = ctx.cum[id(g)] = list(_accumulate([1 / (i + 1) for i in range(len(cities))]))
        return rng.choices(cities, cum_weights=cum)[0]
    if kind == "email_like":
        lang = ctx.lang(g)
        user = f"{_ascii(rng.choice(FIRST[lang]))}.{_ascii(rng.choice(LAST[lang]))}{rng.randint(1, 99)}"
        return f"{user}@{rng.choice(EMAIL_DOMAINS)}"
    if kind == "oid":
        return ObjectId(rng.randbytes(12))
    raise SpecError(f"unknown gen kind {kind}")


def _accumulate(ws):
    total = 0
    for w in ws:
        total += w
        yield total


def _day(d):
    return d.replace(hour=0, minute=0, second=0, microsecond=0)


def _fmt_date(d):
    return d.strftime("%Y-%m-%d") if (d.hour, d.minute, d.second) == (0, 0, 0) else d.strftime("%Y-%m-%dT%H:%M:%SZ")


def cast(v, t):
    """Converts a generated value to the BSON type t; raises SpecError if it cannot."""
    is_num = _num(v)
    if t == "str":
        if isinstance(v, str):
            return v
        if isinstance(v, bool):
            return "true" if v else "false"
        if isinstance(v, dt.datetime):
            return _fmt_date(v)
        if is_num:
            return str(v)
    elif t in ("int", "long"):
        if isinstance(v, str) and re.fullmatch(r"-?\d+", v):
            v = int(v)
        elif is_num:
            v = int(round(v))
        else:
            raise SpecError(f"cannot make {t} from {v!r}")
        if t == "int":
            if not -2**31 <= v < 2**31:
                raise SpecError(f"{v} does not fit in int (use long)")
            return v
        return Int64(v)
    elif t == "double":
        if is_num:
            return float(v)
    elif t == "decimal":
        if is_num or (isinstance(v, str) and re.fullmatch(r"-?\d+(\.\d+)?", v)):
            return Decimal128(Decimal(str(v)))
    elif t == "bool":
        if isinstance(v, bool):
            return v
    elif t == "date":
        if isinstance(v, dt.datetime):
            return v
    elif t == "oid":
        if isinstance(v, ObjectId):
            return v
    raise SpecError(f"cannot make {t} from {v!r}")


def _scalar(f, ctx):
    t = f["type"]
    alts = t.split("|")
    g = f.get("gen")
    if len(alts) == 1:
        return cast(run_gen(g or DEFAULT_GEN[t], ctx), t)
    mix = f.get("mix") or [1] * len(alts)
    cum = ctx.cum.get(id(f))
    if cum is None:
        cum = ctx.cum[id(f)] = list(_accumulate(mix))
    i = ctx.rng.choices(range(len(alts)), cum_weights=cum)[0]
    a = alts[i]
    gi = g[i] if isinstance(g, list) else g
    if gi is None:
        return cast(run_gen(DEFAULT_GEN[a], ctx), a)
    v = run_gen(gi, ctx)
    try:
        return cast(v, a)
    except SpecError:  # the shared gen does not fit this alternative: its default gen
        return cast(run_gen(DEFAULT_GEN[a], ctx), a)


def _ref(f, ctx):
    vals = ctx.targets.get(f["to"])
    if not vals:
        raise SpecError(f"ref {f['to']}: the target has no values")
    sk = f.get("skew", 0)
    if not sk:
        return vals[ctx.rng.randrange(len(vals))]
    cum = ctx.cum.get(id(f))
    if cum is None:
        cum = ctx.cum[id(f)] = list(_accumulate([1 / (i + 1) ** sk for i in range(len(vals))]))
    return ctx.rng.choices(vals, cum_weights=cum)[0]


def _value(f, ctx):
    t = f["type"]
    if t == "obj":
        return _object(f["fields"], ctx)
    if t == "array":
        of = f["of"]
        lo, hi = f.get("len", [0, 3])
        n = ctx.rng.randint(lo, hi)
        if of["type"] == "obj":
            return [_object(of["fields"], ctx) for _ in range(n)]
        if not f.get("unique"):
            return [_value(of, ctx) for _ in range(n)]
        out = []
        for _ in range(n * 20):
            if len(out) == n:
                break
            v = _value(of, ctx)
            if v not in out:
                out.append(v)
        return out
    if t == "ref":
        return _ref(f, ctx)
    return _scalar(f, ctx)


def _object(fields, ctx):
    doc = {}
    for f in fields:
        if f["path"] == "_id":
            continue
        r = ctx.rng.random()
        if r < f.get("optional", 0):
            continue
        v = None if r < f.get("optional", 0) + f.get("null", 0) else _value(f, ctx)
        segs = field_name(f["path"]).split(".")
        d = doc
        for s in segs[:-1]:
            d = d.setdefault(s, {})
        d[segs[-1]] = v
    return doc


def _rng(spec, seed, coll):
    return random.Random(f"{spec['id']}|{seed}|{coll}")


def generate(spec, seed, limit=None):
    """Documents of every collection, {name: [docs]} in spec order. Pure; raises SpecError."""
    colls = {c["name"]: c for c in spec["collections"]}
    targets = {}
    out = {}
    ref_ts = int(parse_ref_date(spec).timestamp())
    for name in _ref_order(spec):
        c = colls[name]
        rng = _rng(spec, seed, name)
        ctx = _Ctx(spec, rng, targets)
        count = c["count"] if limit is None else min(limit, c["count"])
        idf = next((f for f in c["fields"] if f["path"] == "_id"), None)
        ids, seen = [], set()
        for i in range(count):
            if idf is None or idf["type"] == "oid":
                # Monotonic with the index and derived from the seed: 4-byte time + 8 random bytes.
                ids.append(ObjectId(struct.pack(">I", ref_ts - (count - i) * 600) + rng.randbytes(8)))
                continue
            for _ in range(100):
                v = cast(run_gen(idf["gen"], ctx), idf["type"])
                if v not in seen:
                    break
            else:
                raise SpecError(f"{name}: could not draw a unique _id")
            seen.add(v)
            ids.append(v)
        docs = []
        for i in range(count):
            doc = {"_id": ids[i]}
            doc.update(_object(c["fields"], ctx))
            docs.append(doc)
        out[name] = docs
        # Values that refs into this collection may take (top-level scalar fields).
        for f in [{"path": "_id"}] + c["fields"]:
            key = f"{name}.{f['path']}"
            if "." in f["path"] or f["path"].endswith("[]"):
                continue
            targets[key] = [d[f["path"]] for d in docs if d.get(f["path"]) is not None]
    return {c["name"]: out[c["name"]] for c in spec["collections"]}


def load(spec, seed, client):
    """Drops the database and fills it from the spec. Returns its dbHash md5."""
    name = spec["db"]
    docs = generate(spec, seed)
    client.drop_database(name)
    d = client[name]
    for coll, rows in docs.items():
        for i in range(0, len(rows), INSERT_BATCH):
            d[coll].insert_many(rows[i:i + INSERT_BATCH], ordered=True)
    return d.command("dbHash")["md5"]


def main():
    ap = argparse.ArgumentParser(description="Load the askmdb-test databases (seed 0) and check dbHash.")
    ap.add_argument("--uri", required=True, help="MongoDB URI of a throwaway server")
    ap.add_argument("--only", action="append", help="base id (file name in specs/), repeatable")
    args = ap.parse_args()
    expected = json.loads((HERE / "dbhash.json").read_text(encoding="utf-8"))
    ids = args.only or sorted(expected)
    client = pymongo.MongoClient(args.uri, serverSelectionTimeoutMS=5000, tz_aware=True,
                                 tzinfo=dt.timezone.utc)
    bad = 0
    for base in ids:
        spec = json.loads((HERE / "specs" / f"{base}.json").read_text(encoding="utf-8"))
        got = load(spec, SEED, client)
        ok = got == expected[base]
        bad += not ok
        print(f"{base:<18} db={spec['db']:<18} dbHash {got} {'OK' if ok else 'DIFFERENT (expected ' + expected[base] + ')'}")
    if bad:
        sys.exit(f"{bad} database(s) differ from dbhash.json: results may not match the references")


if __name__ == "__main__":
    main()