"""Concept-level learning graph.

Data-driven registry of teachable concepts, keyed by the SAME ``topic_key``
convention the product already persists mastery under:
``"{chapter_catalog_id}:{mission_id}"`` (see ``topic_mastery.topic_key`` and
GuidedClass's assessment sync). For v1 each curated Sound Waves mission is one
concept node; the shape is chapter-agnostic so later chapters extend the data,
not the code.

Honesty rules encoded here:
- Only Sound Waves (``phy-p1-c1``) is a complete curated class; its nodes carry
  real objectives/misconceptions lifted from the hand-authored, source-backed
  lesson seeds (``src/lib/teaching/physicsLessonSeeds.ts``).
- ``pyq`` resources are ``False`` everywhere because no PYQ evidence is curated
  yet (``pyqEvidenceStatus: "not_curated"`` in the seeds).
- Unknown chapters/missions simply are not in the graph — callers must treat
  absence as "content unavailable", never invent coverage.
"""

from __future__ import annotations

from dataclasses import dataclass, field


SOUND_WAVES_CHAPTER_ID = "phy-p1-c1"


@dataclass(frozen=True)
class ConceptResources:
    lesson: bool = False
    quiz: bool = False
    flashcards: bool = False
    board_answer: bool = False
    numericals: bool = False
    pyq: bool = False


@dataclass(frozen=True)
class ConceptNode:
    concept_key: str  # "{chapter_catalog_id}:{mission_id}"
    chapter_catalog_id: str
    mission_id: str
    subject: str
    title: str
    objective: str
    prerequisites: tuple[str, ...]  # concept_keys
    exam_importance: float  # 0..1, relative weight inside the chapter
    typical_misconceptions: tuple[str, ...]
    practice_types: tuple[str, ...]
    estimated_minutes: int
    resources: ConceptResources = field(default_factory=ConceptResources)
    availability: str = "curated"  # curated | notes_only | locked
    textbook_reference: str = ""


def _sw(mission_id: str) -> str:
    return f"{SOUND_WAVES_CHAPTER_ID}:{mission_id}"


_SW_REFERENCE = "Kerala SCERT Physics, Standard X (2025) — Sound Waves, pp. 7-26"

_SW_RESOURCES = ConceptResources(lesson=True, quiz=True, flashcards=True, board_answer=True, pyq=False)
_SW_NUMERIC_RESOURCES = ConceptResources(lesson=True, quiz=True, flashcards=True, board_answer=True, numericals=True, pyq=False)


SOUND_WAVES_CONCEPTS: tuple[ConceptNode, ...] = (
    ConceptNode(
        concept_key=_sw("M1"),
        chapter_catalog_id=SOUND_WAVES_CHAPTER_ID,
        mission_id="M1",
        subject="Physics",
        title="Oscillation, Amplitude, Period and Frequency",
        objective="Understand the basic terms of oscillatory motion using a pendulum and swing.",
        prerequisites=(),
        exam_importance=0.8,
        typical_misconceptions=(
            "One oscillation is just going forward — it must return to complete one.",
        ),
        practice_types=("recall", "mcq", "board_answer"),
        estimated_minutes=25,
        resources=_SW_RESOURCES,
        textbook_reference=_SW_REFERENCE,
    ),
    ConceptNode(
        concept_key=_sw("M2"),
        chapter_catalog_id=SOUND_WAVES_CHAPTER_ID,
        mission_id="M2",
        subject="Physics",
        title="Natural Frequency, Forced Vibration & Resonance",
        objective="Understand natural frequency and how forced vibrations lead to resonance.",
        prerequisites=(_sw("M1"),),
        exam_importance=0.7,
        typical_misconceptions=(
            "Not recognising that the table is forced to vibrate by the mixie (forced vibration).",
            "Forgetting that resonance needs matching frequencies AND produces maximum amplitude.",
        ),
        practice_types=("recall", "mcq", "board_answer"),
        estimated_minutes=25,
        resources=_SW_RESOURCES,
        textbook_reference=_SW_REFERENCE,
    ),
    ConceptNode(
        concept_key=_sw("M3"),
        chapter_catalog_id=SOUND_WAVES_CHAPTER_ID,
        mission_id="M3",
        subject="Physics",
        title="Wave Motion & Types of Waves",
        objective="Learn how waves transfer energy without transferring particles, and differentiate longitudinal and transverse waves.",
        prerequisites=(_sw("M1"),),
        exam_importance=0.85,
        typical_misconceptions=(
            "Thinking the material itself moves forward with the wave — only energy moves.",
        ),
        practice_types=("recall", "mcq", "diagram", "board_answer"),
        estimated_minutes=30,
        resources=_SW_RESOURCES,
        textbook_reference=_SW_REFERENCE,
    ),
    ConceptNode(
        concept_key=_sw("M4"),
        chapter_catalog_id=SOUND_WAVES_CHAPTER_ID,
        mission_id="M4",
        subject="Physics",
        title="Frequency, Wavelength and Wave Speed (v = fλ)",
        objective="Define wavelength, speed of a wave, and understand the relationship v = fλ.",
        prerequisites=(_sw("M3"),),
        exam_importance=1.0,
        typical_misconceptions=(
            "Confusing wavelength with amplitude.",
        ),
        practice_types=("recall", "mcq", "formula", "board_answer"),
        estimated_minutes=30,
        resources=_SW_NUMERIC_RESOURCES,
        textbook_reference=_SW_REFERENCE,
    ),
    ConceptNode(
        concept_key=_sw("M5"),
        chapter_catalog_id=SOUND_WAVES_CHAPTER_ID,
        mission_id="M5",
        subject="Physics",
        title="Numericals using v = fλ",
        objective="Solve exam-style numericals step-by-step using v = fλ.",
        prerequisites=(_sw("M4"),),
        exam_importance=1.0,
        typical_misconceptions=(
            "Substituting wavelength in centimetres without converting to metres.",
        ),
        practice_types=("numerical", "board_answer"),
        estimated_minutes=30,
        resources=_SW_NUMERIC_RESOURCES,
        textbook_reference=_SW_REFERENCE,
    ),
    ConceptNode(
        concept_key=_sw("M6"),
        chapter_catalog_id=SOUND_WAVES_CHAPTER_ID,
        mission_id="M6",
        subject="Physics",
        title="Reflection, Echo & Reverberation",
        objective="Understand how sound reflects, the conditions for an echo, and reverberation.",
        prerequisites=(_sw("M3"),),
        exam_importance=0.9,
        typical_misconceptions=(
            "Thinking reflection doesn't happen in a small room — it does, we just cannot distinguish the echo.",
        ),
        practice_types=("recall", "mcq", "numerical", "board_answer"),
        estimated_minutes=30,
        resources=_SW_NUMERIC_RESOURCES,
        textbook_reference=_SW_REFERENCE,
    ),
    ConceptNode(
        concept_key=_sw("M7"),
        chapter_catalog_id=SOUND_WAVES_CHAPTER_ID,
        mission_id="M7",
        subject="Physics",
        title="Limits of Audibility & Ultrasonic Uses",
        objective="Understand audible range, infrasonic and ultrasonic sounds, and their applications.",
        prerequisites=(_sw("M4"),),
        exam_importance=0.7,
        typical_misconceptions=(
            "Assuming humans can hear everything — dogs and bats hear higher frequencies than us.",
        ),
        practice_types=("recall", "mcq", "board_answer"),
        estimated_minutes=25,
        resources=_SW_RESOURCES,
        textbook_reference=_SW_REFERENCE,
    ),
    ConceptNode(
        concept_key=_sw("M8"),
        chapter_catalog_id=SOUND_WAVES_CHAPTER_ID,
        mission_id="M8",
        subject="Physics",
        title="Seismic Waves and Tsunami",
        objective="Understand the destructive power of seismic waves and tsunamis.",
        prerequisites=(_sw("M3"),),
        exam_importance=0.6,
        typical_misconceptions=(
            "Waves are not just sound or light — they can carry massive destructive energy.",
        ),
        practice_types=("recall", "mcq", "board_answer"),
        estimated_minutes=25,
        resources=_SW_RESOURCES,
        textbook_reference=_SW_REFERENCE,
    ),
    ConceptNode(
        concept_key=_sw("M9"),
        chapter_catalog_id=SOUND_WAVES_CHAPTER_ID,
        mission_id="M9",
        subject="Physics",
        title="Sound Waves Chapter Test & Revision",
        objective="Complete a source-backed final chapter test and turn remaining mistakes into targeted revision.",
        prerequisites=tuple(_sw(f"M{index}") for index in range(1, 9)),
        exam_importance=1.0,
        typical_misconceptions=(
            "Knowing isolated definitions without connecting the formula, condition and application.",
        ),
        practice_types=("revision", "chapter_test", "numerical", "board_answer"),
        estimated_minutes=40,
        resources=_SW_NUMERIC_RESOURCES,
        textbook_reference=_SW_REFERENCE,
    ),
)


_CONCEPTS_BY_KEY: dict[str, ConceptNode] = {node.concept_key: node for node in SOUND_WAVES_CONCEPTS}
_CONCEPTS_BY_CHAPTER: dict[str, tuple[ConceptNode, ...]] = {SOUND_WAVES_CHAPTER_ID: SOUND_WAVES_CONCEPTS}


def concept_for(topic_key: str) -> ConceptNode | None:
    return _CONCEPTS_BY_KEY.get(topic_key)


def concepts_for_chapter(chapter_catalog_id: str) -> tuple[ConceptNode, ...]:
    return _CONCEPTS_BY_CHAPTER.get(chapter_catalog_id, ())


def all_concepts() -> tuple[ConceptNode, ...]:
    return SOUND_WAVES_CONCEPTS


def prerequisites_met(concept: ConceptNode, secure_or_developing_keys: set[str]) -> bool:
    """A concept may be scheduled as NEW learning only when every prerequisite
    has at least been introduced/learned (present in the provided key set)."""
    return all(prerequisite in secure_or_developing_keys for prerequisite in concept.prerequisites)


def ordered_chapter_concepts(chapter_catalog_id: str) -> list[ConceptNode]:
    """Concepts in a safe teaching order (prerequisites before dependants).

    The seed data is already authored in teaching order (M1..M9); this sorts
    defensively anyway so data edits cannot silently break ordering.
    """
    nodes = list(concepts_for_chapter(chapter_catalog_id))
    placed: list[ConceptNode] = []
    placed_keys: set[str] = set()
    remaining = nodes[:]
    while remaining:
        progressed = False
        for node in list(remaining):
            if all(prerequisite in placed_keys for prerequisite in node.prerequisites):
                placed.append(node)
                placed_keys.add(node.concept_key)
                remaining.remove(node)
                progressed = True
        if not progressed:  # cycle in data — fail safe by appending as-authored
            placed.extend(remaining)
            break
    return placed


def concept_to_dict(node: ConceptNode) -> dict[str, object]:
    return {
        "concept_key": node.concept_key,
        "chapter_catalog_id": node.chapter_catalog_id,
        "mission_id": node.mission_id,
        "subject": node.subject,
        "title": node.title,
        "objective": node.objective,
        "prerequisites": list(node.prerequisites),
        "exam_importance": node.exam_importance,
        "typical_misconceptions": list(node.typical_misconceptions),
        "practice_types": list(node.practice_types),
        "estimated_minutes": node.estimated_minutes,
        "resources": {
            "lesson": node.resources.lesson,
            "quiz": node.resources.quiz,
            "flashcards": node.resources.flashcards,
            "board_answer": node.resources.board_answer,
            "numericals": node.resources.numericals,
            "pyq": node.resources.pyq,
        },
        "availability": node.availability,
        "textbook_reference": node.textbook_reference,
    }