import argparse
import json
from pathlib import Path

from .common import ENUMS_DIR, ROOT, TEMPLATES_DIR, write_if_changed
from .data_codegen import SchemaWalker
from .enum_codegen import emit_pure_enum, emit_table_enum
from .validate import validate_data_yamls


def inputs_newer_than(stamp: Path) -> bool:
    if not stamp.exists():
        return True
    stamp_mtime = stamp.stat().st_mtime
    schemas_dir = ROOT / "data" / "schemas"
    inputs = [
        *Path(__file__).parent.glob("*.py"),
        *TEMPLATES_DIR.glob("*.j2"),
        *ENUMS_DIR.glob("*.yaml"),
        *schemas_dir.glob("*.schema.json"),
        *(schemas_dir / "enums").glob("*.codegen.json"),
        *(ROOT / "data").glob("*.yaml"),
    ]
    return any(p.stat().st_mtime > stamp_mtime for p in inputs)


def main():
    """No-op if stamp is newer than input files and `--validate` wasn't passed."""
    parser = argparse.ArgumentParser()
    parser.add_argument("build_dir")
    parser.add_argument(
        "--validate",
        action="store_true",
        help="Also run schema validation.",
    )
    args = parser.parse_args()

    build_root = Path(args.build_dir)
    stamp = build_root / "generated" / ".codegen.stamp"
    if not inputs_newer_than(stamp) and not args.validate:
        return

    out_dir = build_root / "generated" / "data" / "enums"
    data_out_dir = build_root / "generated" / "data"
    lua_out_dir = ROOT / "scripts" / "enum"
    keyset_dir = ROOT / "data" / "schemas" / "enums"
    for d in (out_dir, data_out_dir, lua_out_dir, keyset_dir):
        d.mkdir(parents=True, exist_ok=True)

    # Enums: pure (data/enums/*.yaml) + table-derived (meta.enum: inside a data file).
    enums: list[dict] = []
    for p in sorted(ENUMS_DIR.glob("*.yaml")):
        enums.append(emit_pure_enum(p))
    for p in sorted((ROOT / "data").rglob("*.yaml")):
        if p.is_relative_to(ENUMS_DIR):
            continue
        print(f"scanning {p.relative_to(ROOT).as_posix()} for embedded enum ...", flush=True)
        result = emit_table_enum(p)
        if result is not None:
            enums.append(result)

    for e in enums:
        write_if_changed(out_dir / (e["name"] + ".h"), e["header"])
        if e["lua"]:
            write_if_changed(lua_out_dir / (e["lua"]["name"] + ".codegen.lua"), e["lua"]["content"])
        # Keyset schema lets other schemas $ref the list of valid values for IDE completion + CI checks.
        keyset = {
            "$schema": "https://json-schema.org/draft/2020-12/schema",
            "$id": f"enums/{e['name']}.codegen.json",
            "description": f"GENERATED from {e['source_name']}. Do not edit.",
            "type": "string",
            "enum": list(e["values"].keys()),
        }
        write_if_changed(keyset_dir / (e["name"] + ".codegen.json"), json.dumps(keyset, indent=2) + "\n")

    schemas_dir = ROOT / "data" / "schemas"
    walker = SchemaWalker()
    data_names: list[str] = []
    for schema_path in sorted(schemas_dir.glob("*.schema.json")):
        print(f"rendering {schema_path.relative_to(ROOT).as_posix()} ...", flush=True)
        result = walker.emit(schema_path)
        if result is None:
            continue
        write_if_changed(data_out_dir / (result["name"] + ".h"), result["pod"])
        write_if_changed(data_out_dir / (result["name"] + "_populator.h"), result["populator"])
        data_names.append(result["name"])

    manifest_lines = ["// GENERATED by tools/codegen. Do not edit.", "#pragma once", ""]
    for name in sorted(data_names):
        manifest_lines.append(f'#include "data/{name}.h"')
        manifest_lines.append(f'#include "data/{name}_populator.h"')
    write_if_changed(data_out_dir / "all.h", "\n".join(manifest_lines) + "\n")

    stamp.parent.mkdir(parents=True, exist_ok=True)
    stamp.touch()

    if args.validate:
        validate_data_yamls(schemas_dir, keyset_dir, build_root)


if __name__ == "__main__":
    main()