"""Tests for mandate service: advance_mandate, assign_mandatee, revoke_mandate, create_vote_session_for_step.

These are pure unit tests that mock the database layer to test
the service logic in isolation.
"""

from __future__ import annotations

import uuid
from datetime import datetime, timezone
from unittest.mock import AsyncMock, MagicMock

import pytest

sqlalchemy = pytest.importorskip("sqlalchemy", reason="sqlalchemy required for mandate service tests")

from app.services.mandate_service import (  # noqa: E402
    advance_mandate,
    assign_mandatee,
    create_vote_session_for_step,
    revoke_mandate,
)


# ---------------------------------------------------------------------------
# Helpers: mock objects that behave like SQLAlchemy models
# ---------------------------------------------------------------------------


def _make_step(
    step_id: uuid.UUID | None = None,
    mandate_id: uuid.UUID | None = None,
    step_order: int = 0,
    step_type: str = "formulation",
    status: str = "pending",
    vote_session_id: uuid.UUID | None = None,
) -> MagicMock:
    """Create a mock MandateStep."""
    step = MagicMock()
    step.id = step_id or uuid.uuid4()
    step.mandate_id = mandate_id or uuid.uuid4()
    step.step_order = step_order
    step.step_type = step_type
    step.title = None
    step.description = None
    step.status = status
    step.vote_session_id = vote_session_id
    step.outcome = None
    step.created_at = datetime.now(timezone.utc)
    return step


def _make_mandate(
    mandate_id: uuid.UUID | None = None,
    title: str = "Mandat de test",
    mandate_type: str = "techcomm",
    status: str = "draft",
    mandatee_id: uuid.UUID | None = None,
    decision_id: uuid.UUID | None = None,
    steps: list | None = None,
) -> MagicMock:
    """Create a mock Mandate."""
    mandate = MagicMock()
    mandate.id = mandate_id or uuid.uuid4()
    mandate.title = title
    mandate.description = None
    mandate.mandate_type = mandate_type
    mandate.status = status
    mandate.mandatee_id = mandatee_id
    mandate.decision_id = decision_id
    mandate.starts_at = None
    mandate.ends_at = None
    mandate.created_at = datetime.now(timezone.utc)
    mandate.updated_at = datetime.now(timezone.utc)
    mandate.steps = steps or []
    return mandate


def _make_identity(identity_id: uuid.UUID | None = None) -> MagicMock:
    """Create a mock DuniterIdentity."""
    identity = MagicMock()
    identity.id = identity_id or uuid.uuid4()
    identity.address = "5GrwvaEF5zXb26Fz9rcQpDWS57CtERHpNehXCPcNoHGKutQY"
    identity.username = "Alice"
    return identity


def _make_protocol(
    protocol_id: uuid.UUID | None = None,
    duration_days: int = 30,
) -> MagicMock:
    """Create a mock VotingProtocol with formula_config."""
    protocol = MagicMock()
    protocol.id = protocol_id or uuid.uuid4()
    protocol.name = "Protocole standard"
    protocol.vote_type = "binary"
    protocol.formula_config = MagicMock()
    protocol.formula_config.duration_days = duration_days
    return protocol


def _make_decision_mock(
    decision_id: uuid.UUID | None = None,
    voting_protocol_id: uuid.UUID | None = None,
) -> MagicMock:
    """Create a mock Decision for the vote session lookup."""
    decision = MagicMock()
    decision.id = decision_id or uuid.uuid4()
    decision.voting_protocol_id = voting_protocol_id
    return decision


def _make_db_for_advance(mandate: MagicMock | None) -> AsyncMock:
    """Create a mock async database session for advance_mandate."""
    db = AsyncMock()

    result = MagicMock()
    result.scalar_one_or_none.return_value = mandate

    db.execute = AsyncMock(return_value=result)
    db.commit = AsyncMock()
    db.refresh = AsyncMock()

    return db


def _make_db_for_assign(
    mandate: MagicMock | None,
    identity: MagicMock | None = None,
) -> AsyncMock:
    """Create a mock async database session for assign_mandatee.

    Sequential execute calls:
    1st -> mandate lookup
    2nd -> identity lookup
    """
    db = AsyncMock()

    call_results = []

    # Mandate result
    mandate_result = MagicMock()
    mandate_result.scalar_one_or_none.return_value = mandate
    call_results.append(mandate_result)

    # Identity result
    if identity is not None or mandate is not None:
        identity_result = MagicMock()
        identity_result.scalar_one_or_none.return_value = identity
        call_results.append(identity_result)

    db.execute = AsyncMock(side_effect=call_results)
    db.commit = AsyncMock()
    db.refresh = AsyncMock()

    return db


def _make_db_for_revoke(mandate: MagicMock | None) -> AsyncMock:
    """Create a mock async database session for revoke_mandate."""
    db = AsyncMock()

    result = MagicMock()
    result.scalar_one_or_none.return_value = mandate

    db.execute = AsyncMock(return_value=result)
    db.commit = AsyncMock()
    db.refresh = AsyncMock()

    return db


def _make_db_for_vote_session(
    mandate: MagicMock | None,
    decision: MagicMock | None = None,
    protocol: MagicMock | None = None,
) -> AsyncMock:
    """Create a mock async database session for create_vote_session_for_step.

    Sequential execute calls:
    1st -> mandate lookup
    2nd -> decision lookup
    3rd -> protocol lookup
    """
    db = AsyncMock()

    call_results = []

    # Mandate result
    mandate_result = MagicMock()
    mandate_result.scalar_one_or_none.return_value = mandate
    call_results.append(mandate_result)

    # Decision result
    if decision is not None:
        decision_result = MagicMock()
        decision_result.scalar_one_or_none.return_value = decision
        call_results.append(decision_result)

    # Protocol result
    if protocol is not None:
        proto_result = MagicMock()
        proto_result.scalar_one_or_none.return_value = protocol
        call_results.append(proto_result)

    db.execute = AsyncMock(side_effect=call_results)
    db.commit = AsyncMock()
    db.refresh = AsyncMock()
    db.flush = AsyncMock()
    db.add = MagicMock()

    return db


# ---------------------------------------------------------------------------
# Tests: advance_mandate
# ---------------------------------------------------------------------------


class TestAdvanceMandate:
    """Test mandate_service.advance_mandate."""

    @pytest.mark.asyncio
    async def test_advance_from_draft_activates_first_step(self):
        """Advancing a draft mandate with pending steps activates the first one
        and moves mandate to candidacy."""
        mandate_id = uuid.uuid4()
        step1 = _make_step(mandate_id=mandate_id, step_order=0, status="pending")
        step2 = _make_step(mandate_id=mandate_id, step_order=1, status="pending")

        mandate = _make_mandate(
            mandate_id=mandate_id,
            status="draft",
            steps=[step1, step2],
        )

        db = _make_db_for_advance(mandate)

        result = await advance_mandate(mandate_id, db)

        assert step1.status == "active"
        assert step2.status == "pending"
        assert mandate.status == "candidacy"
        db.commit.assert_awaited_once()

    @pytest.mark.asyncio
    async def test_advance_completes_active_and_activates_next(self):
        """Advancing completes the current active step and activates the next pending one."""
        mandate_id = uuid.uuid4()
        step1 = _make_step(mandate_id=mandate_id, step_order=0, status="active")
        step2 = _make_step(mandate_id=mandate_id, step_order=1, status="pending")

        mandate = _make_mandate(
            mandate_id=mandate_id,
            status="candidacy",
            steps=[step1, step2],
        )

        db = _make_db_for_advance(mandate)

        result = await advance_mandate(mandate_id, db)

        assert step1.status == "completed"
        assert step2.status == "active"
        db.commit.assert_awaited_once()

    @pytest.mark.asyncio
    async def test_advance_last_step_advances_status(self):
        """When the last active step is completed with no more pending steps,
        the mandate status advances."""
        mandate_id = uuid.uuid4()
        step1 = _make_step(mandate_id=mandate_id, step_order=0, status="completed")
        step2 = _make_step(mandate_id=mandate_id, step_order=1, status="active")

        mandate = _make_mandate(
            mandate_id=mandate_id,
            status="candidacy",
            steps=[step1, step2],
        )

        db = _make_db_for_advance(mandate)

        result = await advance_mandate(mandate_id, db)

        assert step2.status == "completed"
        assert mandate.status == "voting"
        db.commit.assert_awaited_once()

    @pytest.mark.asyncio
    async def test_advance_full_progression(self):
        """A mandate with no steps can progress through all statuses."""
        mandate_id = uuid.uuid4()
        mandate = _make_mandate(
            mandate_id=mandate_id,
            status="draft",
            steps=[],
        )

        statuses_seen = [mandate.status]

        # Advance through all states until completed
        for _ in range(10):  # safety limit
            db = _make_db_for_advance(mandate)
            await advance_mandate(mandate_id, db)
            statuses_seen.append(mandate.status)
            if mandate.status == "completed":
                break

        assert statuses_seen == [
            "draft",
            "candidacy",
            "voting",
            "active",
            "reporting",
            "completed",
        ]

    @pytest.mark.asyncio
    async def test_advance_completed_raises_error(self):
        """Advancing a completed mandate raises ValueError."""
        mandate_id = uuid.uuid4()
        mandate = _make_mandate(
            mandate_id=mandate_id,
            status="completed",
            steps=[],
        )

        db = _make_db_for_advance(mandate)

        with pytest.raises(ValueError, match="statut terminal"):
            await advance_mandate(mandate_id, db)

    @pytest.mark.asyncio
    async def test_advance_revoked_raises_error(self):
        """Advancing a revoked mandate raises ValueError."""
        mandate_id = uuid.uuid4()
        mandate = _make_mandate(
            mandate_id=mandate_id,
            status="revoked",
            steps=[],
        )

        db = _make_db_for_advance(mandate)

        with pytest.raises(ValueError, match="statut terminal"):
            await advance_mandate(mandate_id, db)

    @pytest.mark.asyncio
    async def test_advance_not_found_raises_error(self):
        """Advancing a non-existent mandate raises ValueError."""
        db = _make_db_for_advance(None)

        with pytest.raises(ValueError, match="Mandat introuvable"):
            await advance_mandate(uuid.uuid4(), db)


# ---------------------------------------------------------------------------
# Tests: assign_mandatee
# ---------------------------------------------------------------------------


class TestAssignMandatee:
    """Test mandate_service.assign_mandatee."""

    @pytest.mark.asyncio
    async def test_assign_success(self):
        """Assigning a valid identity to an active mandate succeeds."""
        mandate_id = uuid.uuid4()
        mandatee_id = uuid.uuid4()

        mandate = _make_mandate(
            mandate_id=mandate_id,
            status="active",
        )

        identity = _make_identity(identity_id=mandatee_id)
        db = _make_db_for_assign(mandate, identity)

        result = await assign_mandatee(mandate_id, mandatee_id, db)

        assert mandate.mandatee_id == mandatee_id
        assert mandate.starts_at is not None
        db.commit.assert_awaited_once()

    @pytest.mark.asyncio
    async def test_assign_draft_mandate(self):
        """Assigning to a draft mandate is allowed."""
        mandate_id = uuid.uuid4()
        mandatee_id = uuid.uuid4()

        mandate = _make_mandate(
            mandate_id=mandate_id,
            status="draft",
        )

        identity = _make_identity(identity_id=mandatee_id)
        db = _make_db_for_assign(mandate, identity)

        result = await assign_mandatee(mandate_id, mandatee_id, db)

        assert mandate.mandatee_id == mandatee_id
        db.commit.assert_awaited_once()

    @pytest.mark.asyncio
    async def test_assign_not_found_raises_error(self):
        """Assigning to a non-existent mandate raises ValueError."""
        db = _make_db_for_assign(None)

        with pytest.raises(ValueError, match="Mandat introuvable"):
            await assign_mandatee(uuid.uuid4(), uuid.uuid4(), db)

    @pytest.mark.asyncio
    async def test_assign_completed_raises_error(self):
        """Assigning to a completed mandate raises ValueError."""
        mandate_id = uuid.uuid4()
        mandate = _make_mandate(
            mandate_id=mandate_id,
            status="completed",
        )

        db = _make_db_for_assign(mandate)

        with pytest.raises(ValueError, match="statut terminal"):
            await assign_mandatee(mandate_id, uuid.uuid4(), db)

    @pytest.mark.asyncio
    async def test_assign_revoked_raises_error(self):
        """Assigning to a revoked mandate raises ValueError."""
        mandate_id = uuid.uuid4()
        mandate = _make_mandate(
            mandate_id=mandate_id,
            status="revoked",
        )

        db = _make_db_for_assign(mandate)

        with pytest.raises(ValueError, match="statut terminal"):
            await assign_mandatee(mandate_id, uuid.uuid4(), db)

    @pytest.mark.asyncio
    async def test_assign_identity_not_found_raises_error(self):
        """Assigning a non-existent identity raises ValueError."""
        mandate_id = uuid.uuid4()
        mandate = _make_mandate(
            mandate_id=mandate_id,
            status="active",
        )

        db = _make_db_for_assign(mandate, identity=None)

        with pytest.raises(ValueError, match="Identite Duniter introuvable"):
            await assign_mandatee(mandate_id, uuid.uuid4(), db)


# ---------------------------------------------------------------------------
# Tests: revoke_mandate
# ---------------------------------------------------------------------------


class TestRevokeMandate:
    """Test mandate_service.revoke_mandate."""

    @pytest.mark.asyncio
    async def test_revoke_active_mandate(self):
        """Revoking an active mandate sets status to revoked and cancels steps."""
        mandate_id = uuid.uuid4()
        step1 = _make_step(mandate_id=mandate_id, step_order=0, status="completed")
        step2 = _make_step(mandate_id=mandate_id, step_order=1, status="active")
        step3 = _make_step(mandate_id=mandate_id, step_order=2, status="pending")

        mandate = _make_mandate(
            mandate_id=mandate_id,
            status="active",
            steps=[step1, step2, step3],
        )

        db = _make_db_for_revoke(mandate)

        result = await revoke_mandate(mandate_id, db)

        assert mandate.status == "revoked"
        assert mandate.ends_at is not None
        # Completed steps stay completed
        assert step1.status == "completed"
        # Active and pending steps are cancelled
        assert step2.status == "cancelled"
        assert step3.status == "cancelled"
        db.commit.assert_awaited_once()

    @pytest.mark.asyncio
    async def test_revoke_draft_mandate(self):
        """Revoking a draft mandate is allowed."""
        mandate_id = uuid.uuid4()
        mandate = _make_mandate(
            mandate_id=mandate_id,
            status="draft",
            steps=[],
        )

        db = _make_db_for_revoke(mandate)

        result = await revoke_mandate(mandate_id, db)

        assert mandate.status == "revoked"
        assert mandate.ends_at is not None
        db.commit.assert_awaited_once()

    @pytest.mark.asyncio
    async def test_revoke_not_found_raises_error(self):
        """Revoking a non-existent mandate raises ValueError."""
        db = _make_db_for_revoke(None)

        with pytest.raises(ValueError, match="Mandat introuvable"):
            await revoke_mandate(uuid.uuid4(), db)

    @pytest.mark.asyncio
    async def test_revoke_completed_raises_error(self):
        """Revoking an already completed mandate raises ValueError."""
        mandate_id = uuid.uuid4()
        mandate = _make_mandate(
            mandate_id=mandate_id,
            status="completed",
        )

        db = _make_db_for_revoke(mandate)

        with pytest.raises(ValueError, match="statut terminal"):
            await revoke_mandate(mandate_id, db)

    @pytest.mark.asyncio
    async def test_revoke_already_revoked_raises_error(self):
        """Revoking an already revoked mandate raises ValueError."""
        mandate_id = uuid.uuid4()
        mandate = _make_mandate(
            mandate_id=mandate_id,
            status="revoked",
        )

        db = _make_db_for_revoke(mandate)

        with pytest.raises(ValueError, match="statut terminal"):
            await revoke_mandate(mandate_id, db)


# ---------------------------------------------------------------------------
# Tests: create_vote_session_for_step
# ---------------------------------------------------------------------------


class TestCreateVoteSessionForStep:
    """Test mandate_service.create_vote_session_for_step."""

    @pytest.mark.asyncio
    async def test_create_vote_session_success(self):
        """A vote session is created and linked to the mandate step."""
        mandate_id = uuid.uuid4()
        step_id = uuid.uuid4()
        decision_id = uuid.uuid4()
        protocol_id = uuid.uuid4()

        step = _make_step(
            step_id=step_id,
            mandate_id=mandate_id,
            step_type="vote",
            status="active",
            vote_session_id=None,
        )

        mandate = _make_mandate(
            mandate_id=mandate_id,
            status="voting",
            decision_id=decision_id,
            steps=[step],
        )

        decision = _make_decision_mock(
            decision_id=decision_id,
            voting_protocol_id=protocol_id,
        )

        protocol = _make_protocol(protocol_id=protocol_id, duration_days=14)

        db = _make_db_for_vote_session(mandate, decision, protocol)

        result = await create_vote_session_for_step(mandate_id, step_id, db)

        # The step should now have a vote_session_id set
        assert step.vote_session_id is not None
        db.commit.assert_awaited_once()

    @pytest.mark.asyncio
    async def test_create_vote_session_mandate_not_found(self):
        """ValueError when mandate does not exist."""
        db = _make_db_for_vote_session(None)

        with pytest.raises(ValueError, match="Mandat introuvable"):
            await create_vote_session_for_step(uuid.uuid4(), uuid.uuid4(), db)

    @pytest.mark.asyncio
    async def test_create_vote_session_step_not_found(self):
        """ValueError when step does not belong to the mandate."""
        mandate_id = uuid.uuid4()
        mandate = _make_mandate(mandate_id=mandate_id, decision_id=uuid.uuid4(), steps=[])

        db = _make_db_for_vote_session(mandate)

        with pytest.raises(ValueError, match="Etape introuvable"):
            await create_vote_session_for_step(mandate_id, uuid.uuid4(), db)

    @pytest.mark.asyncio
    async def test_create_vote_session_step_already_has_session(self):
        """ValueError when step already has a vote session."""
        mandate_id = uuid.uuid4()
        step_id = uuid.uuid4()
        existing_session_id = uuid.uuid4()

        step = _make_step(
            step_id=step_id,
            mandate_id=mandate_id,
            vote_session_id=existing_session_id,
        )

        mandate = _make_mandate(
            mandate_id=mandate_id,
            decision_id=uuid.uuid4(),
            steps=[step],
        )

        db = _make_db_for_vote_session(mandate)

        with pytest.raises(ValueError, match="deja une session de vote"):
            await create_vote_session_for_step(mandate_id, step_id, db)

    @pytest.mark.asyncio
    async def test_create_vote_session_no_decision(self):
        """ValueError when mandate has no linked decision."""
        mandate_id = uuid.uuid4()
        step_id = uuid.uuid4()

        step = _make_step(
            step_id=step_id,
            mandate_id=mandate_id,
            vote_session_id=None,
        )

        mandate = _make_mandate(
            mandate_id=mandate_id,
            decision_id=None,
            steps=[step],
        )

        db = _make_db_for_vote_session(mandate)

        with pytest.raises(ValueError, match="Aucune decision liee"):
            await create_vote_session_for_step(mandate_id, step_id, db)