import math

import bpy

from ... import config
from ...core import Check, Issue, contexts
from ..general.objects import ModifiersCheck


class LineartModifiersCheck(ModifiersCheck):
    """Same as the general modifier check, with lineart modifiers allowed."""

    id = "modifiers_lineart"
    label = "Modifiers (lineart)"
    description = "No modifiers other than Line Art, Thickness, Subdivision Surface and Multiresolution."
    contexts = frozenset({contexts.CHAR_LINEART})
    allowed_config_key = "ALLOWED_MODIFIERS_LINEART"


def _color_settings(scene):
    """(key, label, getter, setter) of every color management setting."""
    view = scene.view_settings
    return [
        ("display_device", "Display device",
         lambda: scene.display_settings.display_device,
         lambda v: setattr(scene.display_settings, "display_device", v)),
        ("view_transform", "View transform",
         lambda: view.view_transform, lambda v: setattr(view, "view_transform", v)),
        ("look", "Look", lambda: view.look, lambda v: setattr(view, "look", v)),
        ("exposure", "Exposure", lambda: view.exposure, lambda v: setattr(view, "exposure", v)),
        ("gamma", "Gamma", lambda: view.gamma, lambda v: setattr(view, "gamma", v)),
        ("sequencer_colorspace", "Sequencer colorspace",
         lambda: scene.sequencer_colorspace_settings.name,
         lambda v: setattr(scene.sequencer_colorspace_settings, "name", v)),
        ("working_space", "Working space",
         lambda: getattr(getattr(bpy.data, "colorspace", None), "working_space", None),
         None),
    ]


class ColorManagementCheck(Check):
    id = "color_management"
    label = "Color management"
    description = "Display, view transform, look, exposure, gamma and colorspaces follow the production specs."
    category = "Lineart"
    contexts = frozenset({contexts.CHAR_LINEART})
    fix_description = "Apply the production color management (working space excepted)"

    def run(self, ctx):
        spec = config.COLOR_MANAGEMENT
        for key, label, getter, _setter in _color_settings(ctx.scene):
            expected = spec.get(key)
            if expected is None:
                continue
            value = getter()
            if isinstance(expected, float):
                ok = value is not None and math.isclose(value, expected, abs_tol=1e-6)
            else:
                ok = value == expected
            if not ok:
                yield Issue(f"{label} is '{value}', expected '{expected}'", data={"key": key})

    def fix(self, ctx, issues):
        spec = config.COLOR_MANAGEMENT
        keys = {issue.data.get("key") for issue in issues}
        failed = []
        for key, label, _getter, setter in _color_settings(ctx.scene):
            if key not in keys:
                continue
            if setter is None:
                failed.append(f"{label} must be changed by hand (it converts existing colors)")
                continue
            try:
                setter(spec[key])
            except (TypeError, ValueError) as exc:
                failed.append(f"{label}: {exc}")
        return failed