"""Unit tests for compose pipeline logic in stage5_synthesis.

Covers:
- _build_compose_user_prompt(): XML structure, offset indices, empty existing, page JSON
- Compose-or-create branching: compose triggered vs create fallback
- body_sections_format='v2' on persisted pages
- TechniquePageVideo insertion via pg_insert with on_conflict_do_nothing
"""

from __future__ import annotations

import json
import uuid
from collections import namedtuple
from unittest.mock import MagicMock, patch

import pytest


# ── Lightweight mock objects ─────────────────────────────────────────────────

class _MockContentType:
    """Mimics ContentType enum with .value."""
    def __init__(self, value: str) -> None:
        self.value = value


MockKeyMoment = namedtuple("MockKeyMoment", [
    "id", "title", "summary", "content_type", "start_time", "end_time",
    "plugins", "raw_transcript", "technique_page_id", "source_video_id",
])


def _moment(
    title: str = "Test Moment",
    summary: str = "A moment.",
    content_type: str = "technique_demo",
    start_time: float = 0.0,
    end_time: float = 10.0,
    plugins: list[str] | None = None,
    raw_transcript: str | None = "Some transcript text",
    technique_page_id: uuid.UUID | None = None,
    source_video_id: uuid.UUID | None = None,
) -> MockKeyMoment:
    return MockKeyMoment(
        id=uuid.uuid4(),
        title=title,
        summary=summary,
        content_type=_MockContentType(content_type),
        start_time=start_time,
        end_time=end_time,
        plugins=plugins or [],
        raw_transcript=raw_transcript or "",
        technique_page_id=technique_page_id,
        source_video_id=source_video_id,
    )


class _MockSourceQuality:
    """Mimics source_quality enum with .value."""
    def __init__(self, value: str = "high") -> None:
        self.value = value


class MockTechniquePage:
    """Lightweight stand-in for the ORM TechniquePage."""
    def __init__(
        self,
        title: str = "Reverb Techniques",
        slug: str = "reverb-techniques",
        topic_category: str = "Sound Design",
        summary: str = "A page about reverb.",
        body_sections: list | None = None,
        signal_chains: list | None = None,
        plugins: list[str] | None = None,
        source_quality: str = "high",
        creator_id: uuid.UUID | None = None,
        body_sections_format: str | None = None,
    ):
        self.id = uuid.uuid4()
        self.title = title
        self.slug = slug
        self.topic_category = topic_category
        self.summary = summary
        self.body_sections = body_sections or [{"heading": "Overview", "content": "Intro text."}]
        self.signal_chains = signal_chains or []
        self.plugins = plugins or ["Valhalla VintageVerb"]
        self.source_quality = _MockSourceQuality(source_quality)
        self.creator_id = creator_id or uuid.uuid4()
        self.body_sections_format = body_sections_format


def _cls_info(tags: list[str] | None = None) -> dict:
    return {"topic_category": "Sound Design", "topic_tags": tags or ["reverb", "delay"]}


# ── Import the function under test ───────────────────────────────────────────
# We need to patch modules before importing stages in some tests.
# For _build_compose_user_prompt we can import directly since it's a pure function
# that only depends on _build_moments_text.


@pytest.fixture
def build_compose_prompt():
    """Import _build_compose_user_prompt from stages."""
    from pipeline.stages import _build_compose_user_prompt
    return _build_compose_user_prompt


# ── Tests for _build_compose_user_prompt ─────────────────────────────────────


class TestBuildComposeUserPrompt:
    """Tests for _build_compose_user_prompt XML structure and offset math."""

    def test_compose_prompt_xml_structure(self, build_compose_prompt):
        """Verify output contains all required XML tags."""
        page = MockTechniquePage()
        existing = [_moment(title="Existing 1")]
        new = [(_moment(title="New 1"), _cls_info())]

        result = build_compose_prompt(page, existing, new, "COPYCATT")

        assert "<existing_page>" in result
        assert "</existing_page>" in result
        assert "<existing_moments>" in result
        assert "</existing_moments>" in result
        assert "<new_moments>" in result
        assert "</new_moments>" in result
        assert "<creator>" in result
        assert "</creator>" in result
        assert "COPYCATT" in result

    def test_compose_prompt_offset_indices(self, build_compose_prompt):
        """With 3 existing + 2 new moments, new moments should use [3] and [4]."""
        page = MockTechniquePage()
        existing = [
            _moment(title=f"Existing {i}") for i in range(3)
        ]
        new = [
            (_moment(title=f"New {i}"), _cls_info()) for i in range(2)
        ]

        result = build_compose_prompt(page, existing, new, "COPYCATT")

        # New moments section should have [3] and [4]
        new_section_start = result.index("<new_moments>")
        new_section_end = result.index("</new_moments>")
        new_section = result[new_section_start:new_section_end]

        assert "[3]" in new_section
        assert "[4]" in new_section
        # Should NOT have [0], [1], [2] in the new section
        assert "[0]" not in new_section
        assert "[1]" not in new_section
        assert "[2]" not in new_section

    def test_compose_prompt_empty_existing_moments(self, build_compose_prompt):
        """0 existing moments → new moments start at [0]."""
        page = MockTechniquePage()
        existing = []
        new = [
            (_moment(title="New A"), _cls_info()),
            (_moment(title="New B"), _cls_info()),
        ]

        result = build_compose_prompt(page, existing, new, "COPYCATT")

        new_section_start = result.index("<new_moments>")
        new_section_end = result.index("</new_moments>")
        new_section = result[new_section_start:new_section_end]

        assert "[0]" in new_section
        assert "[1]" in new_section

    def test_compose_prompt_page_json(self, build_compose_prompt):
        """Existing page should be serialized as JSON within <existing_page> tags."""
        page = MockTechniquePage(title="My Page", slug="my-page", topic_category="Mixing")

        result = build_compose_prompt(page, [], [(_moment(), _cls_info())], "Creator")

        page_section_start = result.index("<existing_page>") + len("<existing_page>")
        page_section_end = result.index("</existing_page>")
        page_json_str = result[page_section_start:page_section_end].strip()

        page_dict = json.loads(page_json_str)
        assert page_dict["title"] == "My Page"
        assert page_dict["slug"] == "my-page"
        assert page_dict["topic_category"] == "Mixing"
        assert "summary" in page_dict
        assert "body_sections" in page_dict

    def test_compose_prompt_new_moment_content(self, build_compose_prompt):
        """New moments section includes title, summary, time range, and tags."""
        page = MockTechniquePage()
        m = _moment(title="Sidechain Pump", summary="How to create a sidechain pump",
                     start_time=30.0, end_time=45.5, plugins=["FabFilter Pro-C 2"])
        new = [(m, _cls_info(tags=["compression", "sidechain"]))]

        result = build_compose_prompt(page, [], new, "Creator")

        new_section_start = result.index("<new_moments>")
        new_section_end = result.index("</new_moments>")
        new_section = result[new_section_start:new_section_end]

        assert "Sidechain Pump" in new_section
        assert "How to create a sidechain pump" in new_section
        assert "30.0s" in new_section
        assert "45.5s" in new_section
        assert "FabFilter Pro-C 2" in new_section
        assert "compression" in new_section
        assert "sidechain" in new_section


# ── Tests for compose-or-create branching ────────────────────────────────────


class TestComposeOrCreateBranching:
    """Tests for the compose-or-create detection and branching in stage5_synthesis.

    Full integration-level mocking of stage5_synthesis is fragile (many DB queries).
    Instead, we verify:
    1. The code structure has correct branching (compose_target check → two paths)
    2. _compose_into_existing calls the LLM with compose prompt and returns parsed result
    """

    def test_compose_branch_exists_in_source(self):
        """Verify stage5 has compose detection → _compose_into_existing call path."""
        from pathlib import Path
        src = Path("backend/pipeline/stages.py").read_text()

        # The compose detection block
        assert "compose_matches = session.execute(" in src
        assert "compose_target = compose_matches[0] if compose_matches else None" in src

        # The compose branch calls _compose_into_existing
        assert "if compose_target is not None:" in src
        assert "_compose_into_existing(" in src

        # The create branch calls _synthesize_chunk
        assert "elif len(moment_group) <= chunk_size:" in src

    def test_create_branch_when_no_compose_target(self):
        """Verify the else/elif branches call _synthesize_chunk, not _compose_into_existing."""
        from pathlib import Path
        src = Path("backend/pipeline/stages.py").read_text()

        # Find the compose branch and the create branch — they're mutually exclusive
        compose_branch_idx = src.index("if compose_target is not None:")
        create_branch_idx = src.index("elif len(moment_group) <= chunk_size:")

        # The create branch must come after the compose branch (same if/elif chain)
        assert create_branch_idx > compose_branch_idx

        # _synthesize_chunk should appear in the create branch, not compose
        create_block = src[create_branch_idx:create_branch_idx + 500]
        assert "_synthesize_chunk(" in create_block

    @patch("pipeline.stages._safe_parse_llm_response")
    @patch("pipeline.stages._make_llm_callback", return_value=lambda **kw: None)
    @patch("pipeline.stages.estimate_max_tokens", return_value=4000)
    @patch("pipeline.stages._load_prompt", return_value="compose system prompt")
    def test_compose_into_existing_calls_llm(
        self, mock_load_prompt, mock_estimate, mock_callback, mock_parse,
    ):
        """_compose_into_existing calls LLM with compose prompt and returns parsed result."""
        from pipeline.schemas import SynthesisResult, SynthesizedPage
        from pipeline.stages import _compose_into_existing

        mock_llm = MagicMock()
        mock_llm.complete.return_value = "raw response"

        synth_page = SynthesizedPage(
            title="Merged Page", slug="merged-page", topic_category="Sound Design",
            summary="Merged", body_sections=[], signal_chains=[], plugins=[],
            source_quality="high", moment_indices=[0, 1],
        )
        mock_parse.return_value = SynthesisResult(pages=[synth_page])

        page = MockTechniquePage()
        existing_moments = [_moment(title="Old Moment")]
        new_moments = [(_moment(title="New Moment"), _cls_info())]

        result = _compose_into_existing(
            page, existing_moments, new_moments,
            "Sound Design", "COPYCATT", "system prompt",
            mock_llm, None, "text", 8000, str(uuid.uuid4()), None,
        )

        # LLM was called
        mock_llm.complete.assert_called_once()
        # The compose prompt template was loaded
        mock_load_prompt.assert_called_once()
        call_args = mock_load_prompt.call_args
        assert "stage5_compose" in call_args[0][0]

        # Result has the expected page
        assert len(result.pages) == 1
        assert result.pages[0].title == "Merged Page"


# ── Tests for body_sections_format and TechniquePageVideo ────────────────────


class TestBodySectionsFormatAndTracking:
    """Tests for body_sections_format='v2' and TechniquePageVideo insertion."""

    def test_body_sections_format_v2_set_on_page(self):
        """Verify the persist section sets body_sections_format='v2' on pages."""
        # Read stages.py source and verify the assignment exists
        from pathlib import Path
        stages_src = Path("backend/pipeline/stages.py").read_text()

        # The line `page.body_sections_format = "v2"` must appear in the persist block
        assert 'page.body_sections_format = "v2"' in stages_src, (
            "body_sections_format = 'v2' assignment not found in stages.py"
        )

    def test_technique_page_video_pg_insert(self):
        """Verify TechniquePageVideo insertion uses pg_insert with on_conflict_do_nothing."""
        from pathlib import Path
        stages_src = Path("backend/pipeline/stages.py").read_text()

        assert "pg_insert(TechniquePageVideo.__table__)" in stages_src, (
            "pg_insert(TechniquePageVideo.__table__) not found in stages.py"
        )
        assert "on_conflict_do_nothing()" in stages_src, (
            "on_conflict_do_nothing() not found in stages.py"
        )

    def test_technique_page_video_values(self):
        """Verify TechniquePageVideo INSERT includes technique_page_id and source_video_id."""
        from pathlib import Path
        stages_src = Path("backend/pipeline/stages.py").read_text()

        # Find the pg_insert block
        idx = stages_src.index("pg_insert(TechniquePageVideo.__table__)")
        block = stages_src[idx:idx + 200]

        assert "technique_page_id" in block
        assert "source_video_id" in block


# ── Tests for category case-insensitivity ────────────────────────────────────


class TestCategoryCaseInsensitive:
    """Verify the compose detection query uses func.lower for category matching."""

    def test_compose_detection_uses_func_lower(self):
        """The compose detection query must use func.lower on both sides."""
        from pathlib import Path
        stages_src = Path("backend/pipeline/stages.py").read_text()

        # Find the compose detection block — need enough window to capture the full query
        idx = stages_src.index("Compose-or-create detection")
        block = stages_src[idx:idx + 600]

        assert "func.lower(TechniquePage.topic_category)" in block
        assert "func.lower(category)" in block