"""Generate TypeScript types from the OpenAPI schema (no npm needed).

Supports the JSON-Schema subset FastAPI/Pydantic emit: objects, arrays, enums/Literals, anyOf with null,
$ref, additionalProperties, primitive formats. Output: one `export type X = {...}` per component schema
plus `Paths` mapping GET endpoints to their response types.
"""

from __future__ import annotations

from typing import Any

HEADER = "// Generated by `politrack openapi --ts` from the FastAPI schema. Do not edit by hand.\n\n"


def ts_type(schema: dict[str, Any]) -> str:
    if "$ref" in schema:
        return schema["$ref"].rsplit("/", 1)[-1]
    if "const" in schema:
        return _literal(schema["const"])
    if "enum" in schema:
        return " | ".join(_literal(v) for v in schema["enum"])
    for key in ("anyOf", "oneOf"):
        if key in schema:
            parts = []
            for sub in schema[key]:
                part = ts_type(sub)
                if part not in parts:
                    parts.append(part)
            return " | ".join(parts)
    kind = schema.get("type")
    if kind == "array":
        inner = ts_type(schema.get("items", {}))
        return f"({inner})[]" if "|" in inner else f"{inner}[]"
    if kind == "object":
        if "properties" in schema:
            return _object(schema)
        extra = schema.get("additionalProperties")
        value = ts_type(extra) if isinstance(extra, dict) and extra else "unknown"
        return f"Record<string, {value}>"
    if kind in ("integer", "number"):
        return "number"
    if kind == "boolean":
        return "boolean"
    if kind == "string":
        return "string"
    if kind == "null":
        return "null"
    return "unknown"


def _literal(value: Any) -> str:
    return f"'{value}'" if isinstance(value, str) else ("null" if value is None else str(value).lower())


def _object(schema: dict[str, Any], indent: str = "") -> str:
    required = set(schema.get("required", []))
    lines = ["{"]
    for name, prop in schema.get("properties", {}).items():
        optional = "" if name in required else "?"
        lines.append(f"{indent}  {name}{optional}: {ts_type(prop)};")
    lines.append(f"{indent}}}")
    return "\n".join(lines)


def to_typescript(openapi: dict[str, Any]) -> str:
    out = [HEADER]
    for name, schema in sorted(openapi.get("components", {}).get("schemas", {}).items()):
        if name in ("HTTPValidationError", "ValidationError"):
            continue
        out.append(f"export type {name} = {ts_type(schema)};\n")
    out.append("\nexport type Paths = {")
    for path, ops in sorted(openapi.get("paths", {}).items()):
        get = ops.get("get")
        if not get:
            continue
        content = get.get("responses", {}).get("200", {}).get("content", {}).get("application/json", {})
        out.append(f"  '{path}': {ts_type(content.get('schema', {})) if content.get('schema') else 'unknown'};")
    out.append("};\n")
    return "\n".join(out)