from __future__ import annotations

from dataclasses import dataclass


@dataclass(frozen=True)
class ChromaSettings:
    green_margin: float = 0.08
    min_green_value: float = 0.22
    min_saturation: float = 0.20
    hue_low: float = 35.0
    hue_high: float = 95.0
    border_ratio: float = 0.04
    min_samples: int = 2048
    hue_sigma_min: float = 7.0
    lab_sigma_min: float = 10.0
    rgb_sigma_min: float = 0.08


@dataclass(frozen=True)
class TrimapSettings:
    sure_bg_threshold: float = 0.92
    sure_fg_threshold: float = 0.12
    unknown_radius_ratio: float = 0.012
    fg_safe_radius_ratio: float = 0.006
    min_unknown_radius: int = 4
    min_fg_safe_radius: int = 2
    # Semantic fusion thresholds (used by fuse_trimap when segmentation is on).
    seg_core_threshold: float = 0.60
    seg_loose_threshold: float = 0.08


@dataclass(frozen=True)
class AlphaPostSettings:
    min_component_area_ratio: float = 0.00001
    fill_hole_area_ratio: float = 0.00002
    alpha_floor: float = 0.002
    alpha_ceil: float = 0.998
    # Chroma-guided alpha suppression: in the unknown band, pull alpha toward 0
    # where background (green) confidence is high, clearing spill in gaps/holes.
    chroma_suppress: bool = True
    chroma_suppress_bg_low: float = 0.35
    chroma_suppress_bg_high: float = 0.80
    chroma_suppress_strength: float = 1.0
    # Segmentation dropout-fill: rescue alpha where ViTMatte cut a region the
    # semantic mask asserts is foreground (green-contaminated wisps it cannot see).
    seg_fill: bool = True
    seg_fill_alpha_max: float = 0.10
    seg_fill_seg_min: float = 0.10
    seg_fill_strength: float = 0.70
    seg_fill_min_area_ratio: float = 0.00002  # drop rescued specks below this area


@dataclass(frozen=True)
class ForegroundSettings:
    enabled: bool = True
    method: str = "ml"  # "ml" (pymatting) or "unmix" (legacy heuristic)
    fallback_to_unmix: bool = True
    ml_regularization: float = 1e-5
    # Legacy "unmix" method parameters (used only when method == "unmix").
    edge_low: float = 0.005
    edge_high: float = 0.995
    min_unmix_alpha: float = 0.08
    unmix_strength: float = 0.70
    local_strength: float = 0.45
    local_blur_radius: int = 11
    local_alpha_threshold: float = 0.92
    local_bg_confidence_max: float = 0.20
    green_excess_margin: float = 0.015
    bg_confidence_weight: float = 0.70


@dataclass(frozen=True)
class DespillSettings:
    enabled: bool = True
    edge_low: float = 0.005
    strength: float = 0.92
    green_excess_margin: float = 0.015
    edge_expand_radius: int = 2
    alpha_weight_floor: float = 0.35


@dataclass(frozen=True)
class RecolorSettings:
    enabled: bool = True
    person_threshold: float = 0.5      # clean reference = subject above this seg/alpha
    coverage_soft: float = 0.08        # recolour ramps in over alpha 0..this
    contam_low: float = 0.02           # residual off-colour where recolour starts
    contam_high: float = 0.12          # residual off-colour for full recolour
    clean_dom_max: float = 0.03        # reference = subject pixels below this off-colour
    propagate_radius_ratio: float = 0.02
    min_reference_weight: float = 0.05
    luminance_strength: float = 0.5    # how far to pull luminance to the clean neighbour


@dataclass(frozen=True)
class ModelSettings:
    model_name: str = "hustvl/vitmatte-small-composition-1k"
    device: str = "cuda"
    matting_method: str = "vitmatte"
    fallback_to_chroma_alpha: bool = False


@dataclass(frozen=True)
class SegmentationSettings:
    enabled: bool = True
    backend: str = "birefnet"  # "birefnet" or "anime-seg"
    model_name: str = "ZhengPeng7/BiRefNet"
    device: str = "cuda"
    input_size: int = 1024


@dataclass(frozen=True)
class PipelineSettings:
    chroma: ChromaSettings = ChromaSettings()
    trimap: TrimapSettings = TrimapSettings()
    alpha_post: AlphaPostSettings = AlphaPostSettings()
    foreground: ForegroundSettings = ForegroundSettings()
    despill: DespillSettings = DespillSettings()
    recolor: RecolorSettings = RecolorSettings()
    model: ModelSettings = ModelSettings()
    segmentation: SegmentationSettings = SegmentationSettings()