import pytest
from django.db import IntegrityError
from taggit.models import Tag

from apps.blog.models import (
    TAG_COLOUR_PALETTE,
    ArticleIndexPage,
    ArticlePage,
    Category,
    HomePage,
    TagMetadata,
    get_auto_tag_colour_css,
)
from apps.blog.tests.factories import AuthorFactory


@pytest.mark.django_db
def test_home_page_creation(home_page):
    assert HomePage.objects.count() == 1


@pytest.mark.django_db
def test_article_index_parent_restriction():
    assert ArticleIndexPage.parent_page_types == ["blog.HomePage"]


@pytest.mark.django_db
def test_article_compute_read_time_excludes_code(home_page):
    index = ArticleIndexPage(title="Articles", slug="articles")
    home_page.add_child(instance=index)
    author = AuthorFactory()
    article = ArticlePage(
        title="A",
        slug="a",
        author=author,
        summary="s",
        body=[("rich_text", "<p>one two three</p>"), ("code", {"language": "python", "raw_code": "x y z"})],
    )
    index.add_child(instance=article)
    article.save()
    assert article.read_time_mins == 1


@pytest.mark.django_db
def test_tag_metadata_css_and_uniqueness():
    tag = Tag.objects.create(name="llms", slug="llms")
    meta = TagMetadata.objects.create(tag=tag, colour="cyan")
    assert meta.get_css_classes()["bg"] == "bg-brand-cyan/10"
    with pytest.raises(IntegrityError):
        TagMetadata.objects.create(tag=tag, colour="pink")


@pytest.mark.django_db
def test_article_default_category_is_assigned(home_page):
    index = ArticleIndexPage(title="Articles", slug="articles")
    home_page.add_child(instance=index)
    author = AuthorFactory()
    article = ArticlePage(
        title="Categorised",
        slug="categorised",
        author=author,
        summary="s",
        body=[("rich_text", "<p>body</p>")],
    )
    index.add_child(instance=article)
    article.save()
    assert article.category.slug == "general"


@pytest.mark.django_db
def test_article_read_time_is_not_recomputed_when_body_text_is_unchanged(home_page, monkeypatch):
    index = ArticleIndexPage(title="Articles", slug="articles")
    home_page.add_child(instance=index)
    author = AuthorFactory()
    article = ArticlePage(
        title="Stable read time",
        slug="stable-read-time",
        author=author,
        summary="s",
        body=[("rich_text", "<p>body words</p>")],
    )
    index.add_child(instance=article)
    article.save()

    def fail_compute():
        raise AssertionError("read time should not be recomputed when body text is unchanged")

    monkeypatch.setattr(article, "_compute_read_time", fail_compute)
    article.title = "Retitled"
    article.save()
    article.refresh_from_db()

    assert article.read_time_mins == 1


@pytest.mark.django_db
def test_category_ordering():
    Category.objects.get_or_create(name="General", slug="general")
    Category.objects.create(name="Z", slug="z", sort_order=2)
    Category.objects.create(name="A", slug="a", sort_order=1)
    names = list(Category.objects.values_list("name", flat=True))
    assert names == ["General", "A", "Z"]


# ── Auto tag colour tests ────────────────────────────────────────────────────


def test_auto_tag_colour_is_deterministic():
    """Same tag name always produces the same colour."""
    css1 = get_auto_tag_colour_css("python")
    css2 = get_auto_tag_colour_css("python")
    assert css1 == css2


def test_auto_tag_colour_is_case_insensitive():
    """Tag colour assignment is case-insensitive."""
    assert get_auto_tag_colour_css("Python") == get_auto_tag_colour_css("python")


def test_auto_tag_colour_returns_valid_palette_entry():
    """Returned CSS dict must be from the palette."""
    css = get_auto_tag_colour_css("llms")
    assert css in TAG_COLOUR_PALETTE


def test_auto_tag_colour_distributes_across_palette():
    """Different tag names should map to multiple palette entries."""
    sample_tags = ["python", "javascript", "rust", "go", "ruby", "java",
                   "typescript", "css", "html", "sql", "llms", "mlops"]
    colours = {get_auto_tag_colour_css(t)["text"] for t in sample_tags}
    assert len(colours) >= 3, "Tags should spread across at least 3 palette colours"


@pytest.mark.django_db
def test_tag_without_metadata_uses_auto_colour():
    """Tags without TagMetadata should get auto-assigned colour, not neutral."""
    tag = Tag.objects.create(name="fastapi", slug="fastapi")
    expected = get_auto_tag_colour_css("fastapi")
    # Verify no metadata exists
    assert not TagMetadata.objects.filter(tag=tag).exists()
    # The template tag helper should fall back to auto colour
    from apps.core.templatetags.core_tags import _resolve_tag_css
    assert _resolve_tag_css(tag) == expected


@pytest.mark.django_db
def test_tag_with_metadata_overrides_auto_colour():
    """Tags with explicit TagMetadata should use that colour."""
    tag = Tag.objects.create(name="django", slug="django")
    TagMetadata.objects.create(tag=tag, colour="pink")
    from apps.core.templatetags.core_tags import _resolve_tag_css
    css = _resolve_tag_css(tag)
    assert css["text"] == "text-brand-pink"


# ── Auto slug tests ──────────────────────────────────────────────────────────


@pytest.mark.django_db
def test_article_save_auto_generates_slug_from_title(home_page):
    """Model save should auto-generate slug from title when slug is empty."""
    index = ArticleIndexPage(title="Articles", slug="articles")
    home_page.add_child(instance=index)
    author = AuthorFactory()
    article = ArticlePage(
        title="My Great Article",
        slug="my-great-article",
        author=author,
        summary="summary",
        body=[("rich_text", "<p>body</p>")],
    )
    index.add_child(instance=article)
    article.save()
    assert article.slug == "my-great-article"


@pytest.mark.django_db
def test_article_save_auto_generates_search_description(article_index):
    """Model save should populate search_description from summary."""
    author = AuthorFactory()
    article = ArticlePage(
        title="SEO Auto",
        slug="seo-auto",
        author=author,
        summary="This is the article summary.",
        body=[("rich_text", "<p>body</p>")],
    )
    article_index.add_child(instance=article)
    article.save()
    assert article.search_description == "This is the article summary."


@pytest.mark.django_db
def test_article_save_preserves_explicit_search_description(article_index):
    """Explicit search_description should not be overwritten."""
    author = AuthorFactory()
    article = ArticlePage(
        title="SEO Explicit",
        slug="seo-explicit",
        author=author,
        summary="Generated summary.",
        search_description="Custom SEO description.",
        body=[("rich_text", "<p>body</p>")],
    )
    article_index.add_child(instance=article)
    article.save()
    assert article.search_description == "Custom SEO description."