"""Tests for JSON style overlay (md2gost.styles.json / --styles)."""

from __future__ import annotations

import json
from pathlib import Path

import docx
import pytest
from docx.enum.text import WD_ALIGN_PARAGRAPH

from md2gost.style_config import (
    StyleConfigError,
    get_preset,
    resolve_style_config,
    style_config_from_dict,
)
from md2gost.styles import apply_document_styles, apply_style_config
from md2gost import page_geometry as pg


TEMPLATE = Path("md2gost/Template.docx")


def test_preset_unchanged_without_overlay():
    cfg = resolve_style_config("mirea")
    assert cfg.page.left_mm == 30
    assert cfg.page.right_mm == 10
    h1 = cfg.styles["Heading 1"]
    assert h1.alignment == "left"
    assert h1.size_pt == 18
    assert h1.all_caps is True


def test_overlay_changes_margins_and_h1(tmp_path: Path):
    overlay = {
        "page": {"left_mm": 20, "right_mm": 20},
        "styles": {
            "Heading 1": {
                "alignment": "center",
                "size_pt": 14,
                "left_indent_cm": 0,
            }
        },
    }
    path = tmp_path / "custom.json"
    path.write_text(json.dumps(overlay), encoding="utf-8")

    cfg = resolve_style_config("mirea", styles_path=path)
    assert cfg.page.left_mm == 20
    assert cfg.page.right_mm == 20
    # Unspecified margins stay from preset
    assert cfg.page.top_mm == 20
    assert cfg.page.bottom_mm == 20
    assert cfg.styles["Heading 1"].alignment == "center"
    assert cfg.styles["Heading 1"].size_pt == 14
    # Unspecified heading fields stay from preset
    assert cfg.styles["Heading 1"].all_caps is True
    assert cfg.styles["Heading 1"].bold is True


def test_unknown_style_name_raises():
    with pytest.raises(StyleConfigError, match="Unknown style name"):
        style_config_from_dict({"styles": {"Heading 9": {"size_pt": 12}}})


def test_unknown_page_key_raises():
    with pytest.raises(StyleConfigError, match="Unknown page key"):
        style_config_from_dict({"page": {"gutter_mm": 5}})


def test_unknown_style_field_raises():
    with pytest.raises(StyleConfigError, match="Unknown style field"):
        style_config_from_dict({"styles": {"Normal": {"color": "red"}}})


def test_cli_overlay_wins_over_near_md(tmp_path: Path):
    near = tmp_path / "md2gost.styles.json"
    near.write_text(
        json.dumps({"page": {"left_mm": 25}, "styles": {"Heading 1": {"size_pt": 16}}}),
        encoding="utf-8",
    )
    cli = tmp_path / "cli.json"
    cli.write_text(
        json.dumps({"page": {"left_mm": 15}, "styles": {"Heading 1": {"alignment": "center"}}}),
        encoding="utf-8",
    )
    cfg = resolve_style_config("mirea", md_dir=tmp_path, styles_path=cli)
    assert cfg.page.left_mm == 15
    assert cfg.styles["Heading 1"].size_pt == 16  # from near-md, not overridden
    assert cfg.styles["Heading 1"].alignment == "center"  # from CLI


def test_apply_overlay_to_document(tmp_path: Path):
    overlay = style_config_from_dict({
        "page": {"left_mm": 20, "right_mm": 20, "top_mm": 20, "bottom_mm": 20},
        "styles": {"Heading 1": {"alignment": "center", "size_pt": 14}},
    })
    doc = docx.Document(str(TEMPLATE))
    apply_document_styles(doc, "mirea", overlay=overlay)
    h1 = doc.styles["Heading 1"]
    assert h1.paragraph_format.alignment == WD_ALIGN_PARAGRAPH.CENTER
    assert abs(h1.font.size.pt - 14) < 0.01
    section = doc.sections[0]
    assert abs(section.left_margin.mm - 20) < 0.1
    assert abs(pg.MARGIN_LEFT.mm - 20) < 0.1


def test_pis_preset_h1_centered():
    doc = docx.Document(str(TEMPLATE))
    apply_style_config(doc, get_preset("pis_custom"))
    h1 = doc.styles["Heading 1"]
    assert h1.paragraph_format.alignment == WD_ALIGN_PARAGRAPH.CENTER
    assert h1.font.all_caps is True