kirche-einfach/backend/components/kirche/form_inputs.py

"""Structured form-input component for kirche-einfach flows.

A flow that starts with :class:`CustomInputForm` declares the fields of its
web form. The API reads the exported node template
(``template`` minus ``code``) and derives ``{json_schema, ui_schema}`` from
the ``lfx.io`` input definitions below — one JSON-Schema property per field,
keyed by ``name``. Field metadata maps as follows:

* ``display_name`` → ``title``, ``info`` → ``description``,
  ``value`` → ``default``, ``options`` → ``enum``
* ``required`` → required array, ``advanced`` → ``ui:collapsed`` hint
* ``_input_type`` → JSON type + widget (see ``app/flows/input_schema.py``)

``collect()`` is fully dynamic: it emits every input except the plumbing
ones (``form_values``, ``code``), so fields can be renamed, added, or
removed in the Langflow code editor without touching this method.
``name`` is the stable JSON key (freely renamable, must stay unique and
non-empty); downstream components read the keys as-is.

When the run envelope names the asked fields (``fields`` list, sent by
the API from the version's form schema), defaults are emitted only for
asked fields — the template may declare fields unknown to this code and
unasked code defaults stay out of the output. Without the list (raw dict,
Langflow playground), all declared defaults apply.

``collect()`` returns ``Data`` (the LFX JSON type), not ``Message``: the
values travel as a real JSON object. A terminal ``ChatOutput`` renders it
as a fenced ```json block; components consuming it should read ``.data``
(or ``get_text()``), not ``.text``.

``FileInput`` is a stub for now: it carries a string reference only, real
upload comes later.
"""

from __future__ import annotations

import json
import re
from typing import ClassVar

from lfx.custom import Component
from lfx.field_typing.range_spec import RangeSpec
from lfx.io import (
    BoolInput,
    DropdownInput,
    FileInput,
    FloatInput,
    IntInput,
    MessageTextInput,
    MultilineInput,
    MultiselectInput,
    Output,
    SecretStrInput,
    SliderInput,
    StrInput,
)
from lfx.schema.data import Data


def _text(value) -> str:
    if value is None:
        return ""
    if hasattr(value, "text"):
        return value.text or ""
    return str(value)


def _json_safe(value):
    """Plain JSON value for one field: unwrap LFX wrappers, keep scalars."""
    if value is None or isinstance(value, (bool, int, float, str)):
        return value
    if isinstance(value, list):
        return [_json_safe(item) for item in value]
    if isinstance(value, dict):
        return {str(key): _json_safe(item) for key, item in value.items()}
    text = getattr(value, "text", None)
    if isinstance(text, str):
        return text
    data = getattr(value, "data", None)
    if isinstance(data, dict):
        return _json_safe(data)
    return str(value)


def _split_conditions(text: str) -> list:
    parts: list = []
    buf: list = []
    quoted = False
    for char in text:
        if char == '"':
            quoted = not quoted
            buf.append(char)
        elif char == "&" and not quoted:
            parts.append("".join(buf))
            buf = []
        else:
            buf.append(char)
    parts.append("".join(buf))
    return [part.strip() for part in parts if part.strip()]


def _parse_condition(token: str):
    field, sep, value = token.partition("=")
    field, value = field.strip(), value.strip()
    if not sep or not field or not value:
        return None
    if len(value) >= 2 and value.startswith('"') and value.endswith('"'):
        value = value[1:-1]
    lowered = value.lower()
    if lowered == "true":
        return field, True
    if lowered == "false":
        return field, False
    try:
        return field, int(value)
    except ValueError:
        pass
    try:
        return field, float(value)
    except ValueError:
        pass
    return field, value


def _field_conditions(info: object) -> list:
    """``[(trigger, value)]`` from a field's ``info`` markers."""
    conditions: list = []

    def _collect(match) -> str:
        for token in _split_conditions(match.group(1)):
            parsed = _parse_condition(token)
            if parsed is not None:
                conditions.append(parsed)
        return ""

    _VISIBLE_RE.sub(_collect, info if isinstance(info, str) else "")
    return conditions


#: Reserved input carrying the run envelope — a real runtime input, so it
#: must stay out of the output (otherwise the whole envelope JSON would
#: leak in as a field value on every path without an asked-fields list).
#: Never name a form field ``form_values``.
PLUMBING_INPUTS = frozenset({"form_values"})

#: ``[visible_if ...]`` marker (same syntax as the backend parser in
#: ``app/flows/input_schema.py`` — keep the two in sync; this module must
#: stay import-light for the LFX runtime and cannot import it).
_VISIBLE_RE = re.compile(r"\[visible_if\s+([^\]]+)\]")


class CustomInputForm(Component):
    display_name = "CustomInput Form"
    description = "Collects structured form values into a single JSON object."
    icon = "ClipboardList"

    inputs: ClassVar[list] = [
        # Plumbing, not a form field: the API posts submitted web-form
        # values as the run envelope (same {"payload": {...}} shape the
        # other kirche components use); they arrive here through a ChatInput
        # entry node and override the defaults below. Hidden in the GUI and
        # skipped by the form parser (show=False).
        MessageTextInput(
            name="form_values",
            display_name="Form values (JSON envelope)",
            info="Submitted values as JSON; merged over the defaults",
            value="",
            show=False,
        ),
        StrInput(
            name="full_name",
            display_name="Full name",
            info="Your first and last name",
            value="",
            required=True,
        ),
        MultilineInput(
            name="notes",
            display_name="Notes",
            info="Anything else we should know",
            value="",
        ),
        SecretStrInput(
            name="password",
            display_name="Password",
            info="Optional access phrase",
            value="",
        ),
        IntInput(
            name="age",
            display_name="Age",
            info="Your age in years",
            value=18,
        ),
        FloatInput(
            name="amount",
            display_name="Amount",
            info="Amount in euros",
            value=0.0,
        ),
        BoolInput(
            name="newsletter",
            display_name="Newsletter",
            info="Send me the parish newsletter",
            value=False,
        ),
        DropdownInput(
            name="department",
            display_name="Department",
            info="Which team is this for",
            options=["Music", "Youth", "Seniors", "Admin"],
            value="Music",
        ),
        MultiselectInput(
            name="topics",
            display_name="Topics",
            info="What are you interested in",
            options=["Worship", "Outreach", "Courses"],
            value=[],
        ),
        SliderInput(
            name="satisfaction",
            display_name="Satisfaction",
            info="How satisfied are you (1-5)",
            value=3,
            range_spec=RangeSpec(min=1, max=5, step=1),
        ),
        FileInput(
            name="attachment",
            display_name="Attachment",
            info="String reference only for now (no upload yet)",
            file_types=["pdf", "png", "jpg"],
        ),
    ]
    outputs: ClassVar[list] = [
        Output(display_name="Form Data", name="form_data", method="collect"),
    ]

    def _field_names(self) -> list:
        """Names of all form fields (every input except the plumbing ones)."""
        inputs = getattr(self, "_inputs", None)
        if isinstance(inputs, dict) and inputs:
            return [name for name in inputs if name not in PLUMBING_INPUTS]
        seen = []
        declared = getattr(self, "inputs", None) or getattr(type(self), "inputs", None) or []
        for inp in declared:
            name = getattr(inp, "name", None)
            if name and name not in PLUMBING_INPUTS and name not in seen:
                seen.append(name)
        return seen

    def _field_value(self, name: str):
        """Runtime value of one input.

        Reads ``_inputs`` directly: a field renamed to e.g. ``name`` would
        otherwise resolve to the component attribute instead of its value.
        """
        inputs = getattr(self, "_inputs", None)
        if isinstance(inputs, dict) and name in inputs:
            return getattr(inputs[name], "value", None)
        try:
            return getattr(self, name, None)
        except (AttributeError, ValueError):
            return None

    def _is_visible(self, name: str, effective: dict) -> bool:
        """Whether a field's branch conditions hold.

        Single pass over effective values (submitted first, code defaults
        after): no recursion, so trigger cycles cannot hang — a stale or
        cyclic marker simply matches or not. Unknown triggers never match.
        """
        inputs = getattr(self, "_inputs", None)
        info = ""
        if isinstance(inputs, dict) and name in inputs:
            info = getattr(inputs[name], "info", "") or ""
        for trigger, expected in _field_conditions(info):
            if trigger == name or trigger not in effective:
                # Self-reference or unknown trigger: fail open (visible),
                # mirroring the backend parser.
                continue
            actual = effective[trigger]
            if isinstance(actual, list):
                if expected not in actual:
                    return False
            elif actual != expected:
                return False
        return True

    def collect(self) -> Data:
        try:
            envelope = json.loads(_text(self.form_values) or "{}")
        except (json.JSONDecodeError, ValueError, AttributeError):
            envelope = {}
        payload: dict = {}
        asked: list | None = None
        if isinstance(envelope, dict):
            # Asked-field list counts only in true envelope shape
            # ({"payload": {...}, "fields": [...]}); a raw dict or a form
            # field literally named "fields" must not confuse it.
            if isinstance(envelope.get("payload"), dict):
                payload = envelope["payload"]
                fields = envelope.get("fields")
                if isinstance(fields, list) and all(isinstance(item, str) for item in fields):
                    asked = [item for item in fields if item]
            else:
                payload = envelope
        # Effective trigger values: submitted first, code defaults after.
        declared = self._field_names()
        effective = {name: _json_safe(self._field_value(name)) for name in declared}
        for key, val in payload.items():
            if isinstance(key, str) and key:
                effective[key] = _json_safe(val)
        # Defaults only for asked AND visible fields (hidden branch fields
        # stay out, like the frontend never submits them); without an asked
        # list, all visible declared fields (Langflow playground).
        scope = [name for name in (asked if asked is not None else declared) if name in declared]
        data = {name: effective[name] for name in scope if self._is_visible(name, effective)}
        # Submitted values win over the field defaults. Unknown keys are
        # kept: the frontend may already know renamed fields this code
        # revision does not declare.
        for key, val in payload.items():
            if isinstance(key, str) and key:
                data[key] = _json_safe(val)
        return Data(data=data)