"""Combat data model — the boundary contract for the whole simulator.

Every combatant (PC from a Foundry sheet or hand-authored monster JSON) is
parsed into a `Combatant` exactly once, at the loading boundary. The engine
never sees raw JSON.
"""

from __future__ import annotations

from typing import Literal

from pydantic import BaseModel, ConfigDict, Field, field_validator

from pf1e_simulator.abilities import AbilitySpec  # noqa: TC001
from pf1e_simulator.dice import DiceExpr, DiceParseError, parse_dice


class _FrozenModel(BaseModel):
    model_config = ConfigDict(frozen=True, extra="forbid")


class AbilityScores(_FrozenModel):
    str_score: int
    dex_score: int
    con_score: int
    int_score: int
    wis_score: int
    cha_score: int


class ACProfile(_FrozenModel):
    total: int
    touch: int
    flat_footed: int


class Saves(_FrozenModel):
    fort: int
    ref: int
    will: int


class DamageComponent(_FrozenModel):
    """One damage roll with its types (e.g. 1d8 piercing).

    The formula accepts an already-parsed DiceExpr (Foundry loader path) or a
    plain notation string like "2d6+3" (hand-authored monster JSON path).
    """

    formula: DiceExpr
    types: list[str] = Field(min_length=1)

    @field_validator("formula", mode="before")
    @classmethod
    def _parse_formula(cls, value: object) -> object:
        if isinstance(value, str):
            try:
                return parse_dice(value)
            except DiceParseError as exc:
                msg = str(exc)
                raise ValueError(msg) from exc
        return value


class AttackSpec(_FrozenModel):
    """One attack menu entry (weapon or natural attack).

    `count` captures repeated identical swings ("2x Talons") without listing
    the same entry twice. `reach_ft` applies to melee/touch kinds,
    `range_increment_ft` to ranged/touch kinds.
    """

    id: str
    name: str
    kind: Literal["melee", "ranged", "touch"]
    attack_bonus: int
    damage: list[DamageComponent] = Field(min_length=1)
    damage_bonus: int = 0
    crit_range: int = Field(default=20, ge=2, le=20)
    crit_mult: int = Field(default=2, ge=2, le=4)
    reach_ft: int = 5
    range_increment_ft: int | None = None
    count: int = Field(default=1, ge=1)


class DamageReduction(_FrozenModel):
    """DR amount and the damage types that bypass it; empty bypass = DR/—."""

    amount: int = Field(ge=1)
    bypass: frozenset[str] = frozenset()


class Combatant(_FrozenModel):
    """A fully parsed combatant, ready for the engine."""

    id: str
    name: str
    level: int = Field(ge=1)
    size: str = "Medium"
    abilities: AbilityScores
    hp_max: int = Field(ge=1)
    ac: ACProfile
    bab: int
    initiative_mod: int
    speed_land_ft: int = Field(ge=0)
    speed_fly_ft: int | None = None
    saves: Saves
    attacks: list[AttackSpec]
    dr: DamageReduction | None = None
    cr: str | None = None
    xp: int | None = None
    source: str = ""
    notes: str = ""
    features: list[AbilitySpec] = []
    spells: list[str] = []