"""PF1e abilities: feats, class features, racial traits, character traits.

All four categories share the same mechanical representation via ``AbilitySpec``.
What differs is the ``category`` (for stacking and display) and ``source_detail``.

This step defines passive feats — permanent stat modifiers that the engine
collects alongside effects and conditions via ``_stat_modifiers``. Active feats
(Power Attack, Rage) and conditional feats (Sneak Attack) will be added in
later steps.

Sources: PRPG Core Rulebook, Feats chapter.
"""

from __future__ import annotations

from dataclasses import dataclass
from typing import Literal

from pf1e_simulator.effects import StatModifier

Category = Literal["feat", "class", "racial", "trait"]


@dataclass(frozen=True)
class AbilitySpec:
    """One feat, class feature, racial trait, or character trait.

    ``effects`` are the StatModifiers this ability grants. For passive feats,
    these are always-on modifiers. For conditional feats, ``condition`` on
    each StatModifier gates applicability (evaluated by the engine).
    """

    name: str
    category: Category
    source_detail: str = ""
    effects: tuple[StatModifier, ...] = ()


# ── Passive combat feats ─────────────────────────────────────────────────────
# Weapon Focus: +1 attack with a specific weapon (untyped, CRB)
def weapon_focus(weapon_name: str) -> AbilitySpec:
    return AbilitySpec(
        name=f"Weapon Focus ({weapon_name})",
        category="feat",
        source_detail="feat lv1",
        effects=(
            StatModifier(target="attack", value=1, weapon_filter=weapon_name),
        ),
    )


# Toughness: +1 HP per Hit Die (approximated as +level HP, untyped, CRB)
# For simplicity at this stage, we model it as a flat HP bonus.
# The engine doesn't yet compute per-HD bonuses, so the caller sets the value.
def toughness(level: int) -> AbilitySpec:
    return AbilitySpec(
        name="Toughness",
        category="feat",
        source_detail="feat lv1",
        effects=(
            StatModifier(target="hp", value=level),
        ),
    )


# Iron Will: +2 will saves (untyped, CRB)
IRON_WILL = AbilitySpec(
    name="Iron Will",
    category="feat",
    source_detail="feat lv1",
    effects=(
        StatModifier(target="will", value=2),
    ),
)

# Great Fortitude: +2 fortitude saves (untyped, CRB)
GREAT_FORTITUDE = AbilitySpec(
    name="Great Fortitude",
    category="feat",
    source_detail="feat lv1",
    effects=(
        StatModifier(target="fort", value=2),
    ),
)

# Lightning Reflexes: +2 reflex saves (untyped, CRB)
LIGHTNING_REFLEXES = AbilitySpec(
    name="Lightning Reflexes",
    category="feat",
    source_detail="feat lv1",
    effects=(
        StatModifier(target="ref", value=2),
    ),
)

# Alertness: +2 Perception and Sense Motive (untyped, CRB)
# Modeled as +2 will (Wisdom-based) since skills aren't implemented
ALERTNESS = AbilitySpec(
    name="Alertness",
    category="feat",
    source_detail="feat lv1",
    effects=(
        StatModifier(target="will", value=2),
    ),
)

# Point-Blank Shot: +1 attack and +1 damage with ranged weapons within 30 ft.
# Untyped, conditional (CRB).
POINT_BLANK_SHOT = AbilitySpec(
    name="Point-Blank Shot",
    category="feat",
    source_detail="feat lv1",
    effects=(
        StatModifier(
            target="attack", value=1, condition="target_within_30ft_ranged"
        ),
        StatModifier(
            target="damage", value=1, condition="target_within_30ft_ranged"
        ),
    ),
)

# Precise Shot: no -4 penalty for shooting into melee (CRB)
# This is a behavioral flag, not a stat modifier — it will be handled
# as a SpecialBehavior in a later step. Defined here for completeness.
PRECISE_SHOT = AbilitySpec(
    name="Precise Shot",
    category="feat",
    source_detail="feat lv1",
)

# Dodge: +1 dodge bonus to AC (dodge type, stacks, CRB)
DODGE = AbilitySpec(
    name="Dodge",
    category="feat",
    source_detail="feat lv1",
    effects=(
        StatModifier(target="ac", value=1, bonus_type="dodge"),
    ),
)

# Power Attack: active feat — declare at turn start, -X atk / +2X dmg on all
# melee attacks this turn, where X = BAB//4 + 1 (min 1). No passive modifiers;
# the engine checks for this feat and the ``power_attack`` flag on state.
POWER_ATTACK = AbilitySpec(
    name="Power Attack",
    category="feat",
    source_detail="feat lv1",
)