from __future__ import annotations

import argparse
import json
import re
from collections import defaultdict
from pathlib import Path
from typing import Any

import yaml


ROOT = Path(__file__).resolve().parents[2]
SOURCE = ROOT / "spec" / "13_formula_registry.yaml"


def load_yaml(path: Path) -> dict[str, Any]:
    return yaml.safe_load(path.read_text(encoding="utf-8")) or {}


def to_snake(name: str) -> str:
    slug = re.sub(r"[^0-9A-Za-z]+", "_", name).strip("_").lower()
    return slug or "formula"


def write_text(path: Path, text: str) -> None:
    path.parent.mkdir(parents=True, exist_ok=True)
    path.write_text(text, encoding="utf-8")


def build_stub(formula_id: str, spec: dict[str, Any]) -> str:
    inputs = spec.get("inputs") or []
    outputs = spec.get("outputs") or spec.get("output_fields") or []
    owner = spec.get("owner")
    status = spec.get("status")
    input_fields = [item.get("field") for item in inputs if isinstance(item, dict) and item.get("field")]
    return (
        f'"""Auto-generated formula stub for {formula_id}."""\n'
        f"\n"
        f"FORMULA_ID = {formula_id!r}\n"
        f"FORMULA_OWNER = {owner!r}\n"
        f"FORMULA_STATUS = {status!r}\n"
        f"FORMULA_INPUT_FIELDS = {input_fields!r}\n"
        f"FORMULA_OUTPUT_FIELDS = {outputs!r}\n"
        f"\n"
        f"def execute(inputs: dict[str, object]) -> dict[str, object]:\n"
        f"    raise NotImplementedError({formula_id!r} + ' is a generated stub.')\n"
    )


def build_golden_test(formula_id: str, spec: dict[str, Any]) -> str:
    slug = to_snake(formula_id)
    outputs = spec.get("outputs") or spec.get("output_fields") or []
    return (
        f'"""Auto-generated golden test stub for {formula_id}."""\n'
        f"\n"
        f"def test_{slug}_golden_stub_exists() -> None:\n"
        f"    assert {formula_id!r}\n"
        f"\n"
        f"def test_{slug}_declares_outputs() -> None:\n"
        f"    outputs = {outputs!r}\n"
        f"    assert isinstance(outputs, list)\n"
        f"    assert outputs\n"
    )


def build_schema_fragment(formula_id: str, spec: dict[str, Any]) -> dict[str, Any]:
    inputs = spec.get("inputs") or []
    outputs = spec.get("outputs") or spec.get("output_fields") or []
    return {
        "$schema": "https://json-schema.org/draft/2020-12/schema",
        "$id": f"schema://formula/{formula_id}",
        "title": formula_id,
        "type": "object",
        "properties": {
            "formula_id": {"const": formula_id},
            "owner": {"type": "string"},
            "status": {"type": "string"},
            "inputs": {"type": "array", "items": {"type": "string"}},
            "outputs": {"type": "array", "items": {"type": "string"}},
        },
        "required": ["formula_id", "owner", "status", "inputs", "outputs"],
        "x_formula_inputs": [
            item.get("field")
            for item in inputs
            if isinstance(item, dict) and item.get("field")
        ],
        "x_formula_outputs": outputs,
    }


def main() -> int:
    parser = argparse.ArgumentParser(description="Compile formula registry stubs and artifacts.")
    parser.add_argument("--dry-run", action="store_true", help="Validate inputs without writing files.")
    parser.add_argument("--out-report", default=str(ROOT / "Temp" / "formula_compile_report_v1.json"))
    parser.add_argument("--out-graph", default=str(ROOT / "Temp" / "formula_dependency_graph_v1.json"))
    args = parser.parse_args()

    source = load_yaml(SOURCE)
    formulas = (source.get("formula_registry") or {}).get("formulas") or {}
    if not isinstance(formulas, dict):
        raise TypeError("formula_registry.formulas must be a mapping")

    runtime_dir = ROOT / "runtime" / "python" / "core" / "formulas" / "generated"
    golden_dir = ROOT / "tests" / "golden" / "generated"
    schema_dir = ROOT / "schemas" / "generated"

    output_field_map: dict[str, set[str]] = defaultdict(set)
    for formula_id, spec in formulas.items():
        if not isinstance(spec, dict):
            continue
        outputs = spec.get("outputs") or spec.get("output_fields") or []
        for field in outputs:
            if isinstance(field, str):
                output_field_map[field].add(formula_id)

    dependency_graph: dict[str, list[str]] = {}
    generated_count = 0
    active_count = 0
    for formula_id in sorted(formulas):
        spec = formulas[formula_id] or {}
        status = str(spec.get("status", "active")).lower()
        if status not in {"deprecated", "removed"}:
            active_count += 1
        stub_name = f"{to_snake(formula_id)}.py"
        golden_name = f"{to_snake(formula_id)}_golden.py"
        schema_name = f"{to_snake(formula_id)}.schema.json"

        input_fields = [
            item.get("field")
            for item in (spec.get("inputs") or [])
            if isinstance(item, dict) and item.get("field")
        ]
        dependencies = sorted(
            {
                producer
                for field in input_fields
                for producer in output_field_map.get(field, set())
                if producer != formula_id
            }
        )
        dependency_graph[formula_id] = dependencies

        if not args.dry_run:
            write_text(runtime_dir / stub_name, build_stub(formula_id, spec))
            write_text(golden_dir / golden_name, build_golden_test(formula_id, spec))
            write_text(schema_dir / schema_name, json.dumps(build_schema_fragment(formula_id, spec), ensure_ascii=False, indent=2) + "\n")
        generated_count += 1

    report = {
        "source": str(SOURCE.relative_to(ROOT)),
        "formula_count": len(formulas),
        "active_formula_count": active_count,
        "generated_stub_count": generated_count,
        "golden_stub_count": generated_count,
        "schema_fragment_count": generated_count,
        "dependency_graph_node_count": len(dependency_graph),
        "status": "OK",
    }
    if not args.dry_run:
        write_text(Path(args.out_report), json.dumps(report, ensure_ascii=False, indent=2) + "\n")
        write_text(Path(args.out_graph), json.dumps(dependency_graph, ensure_ascii=False, indent=2) + "\n")
        for package_dir in (runtime_dir, golden_dir, schema_dir):
            init_file = package_dir / "__init__.py"
            if not init_file.exists():
                write_text(init_file, '"""Auto-generated package."""\n')

    print(json.dumps(report, ensure_ascii=False, indent=2))
    return 0


if __name__ == "__main__":
    raise SystemExit(main())