"""Integration tests for mandate flows: nomination, lifecycle, assignment, revocation.

Uses a real in-memory SQLite database — no mocks of the DB layer.
Tests the service functions directly to verify interconnected business logic.
"""

from __future__ import annotations

import uuid
from datetime import datetime, timezone

import pytest
import pytest_asyncio
from sqlalchemy.ext.asyncio import AsyncSession, async_sessionmaker, create_async_engine
from sqlalchemy.orm import selectinload
from sqlalchemy import select

import app.models  # noqa: F401 — registers all models with Base.metadata
from app.database import Base
from app.models.mandate import Mandate, MandateStep
from app.models.user import DuniterIdentity
from app.services.mandate_service import (
    advance_mandate,
    assign_mandatee,
    revoke_mandate,
)


# ---------------------------------------------------------------------------
# Fixtures
# ---------------------------------------------------------------------------


@pytest_asyncio.fixture
async def engine():
    eng = create_async_engine("sqlite+aiosqlite:///:memory:", echo=False)
    async with eng.begin() as conn:
        await conn.run_sync(Base.metadata.create_all)
    yield eng
    await eng.dispose()


@pytest_asyncio.fixture
async def db(engine):
    factory = async_sessionmaker(engine, class_=AsyncSession, expire_on_commit=False)
    async with factory() as session:
        yield session


async def _mk_identity(db: AsyncSession, display_name: str = "Alice") -> DuniterIdentity:
    ident = DuniterIdentity(
        id=uuid.uuid4(),
        address=f"5{uuid.uuid4().hex[:46]}",
        display_name=display_name,
        wot_status="member",
        is_smith=False,
        is_techcomm=False,
    )
    db.add(ident)
    await db.commit()
    await db.refresh(ident)
    return ident


async def _mk_mandate(
    db: AsyncSession,
    *,
    mandatee_id: uuid.UUID | None = None,
    origin_id: uuid.UUID | None = None,
    status: str = "draft",
    steps: list[dict] | None = None,
) -> Mandate:
    mandate = Mandate(
        id=uuid.uuid4(),
        title="Mandat test",
        mandate_type="functional",
        status=status,
        mandatee_id=mandatee_id,
        origin_id=origin_id,
    )
    db.add(mandate)
    await db.flush()

    for i, s in enumerate(steps or []):
        step = MandateStep(
            id=uuid.uuid4(),
            mandate_id=mandate.id,
            step_order=i,
            step_type=s.get("step_type", "formulation"),
            title=s.get("title"),
            status=s.get("status", "pending"),
        )
        db.add(step)

    await db.commit()
    await db.refresh(mandate)
    return mandate


async def _reload(db: AsyncSession, mandate_id: uuid.UUID) -> Mandate:
    result = await db.execute(
        select(Mandate)
        .options(
            selectinload(Mandate.steps),
            selectinload(Mandate.origin_identity),
            selectinload(Mandate.mandatee),
        )
        .where(Mandate.id == mandate_id)
    )
    return result.scalar_one()


# ---------------------------------------------------------------------------
# TestMandateOrigin
# ---------------------------------------------------------------------------


class TestMandateOrigin:
    """origin_id must link to a real DuniterIdentity and expose display_name."""

    @pytest.mark.asyncio
    async def test_origin_id_linked(self, db: AsyncSession):
        author = await _mk_identity(db, "Baptiste")
        mandate = await _mk_mandate(db, origin_id=author.id)

        loaded = await _reload(db, mandate.id)

        assert loaded.origin_id == author.id
        assert loaded.origin_display_name == "Baptiste"

    @pytest.mark.asyncio
    async def test_origin_id_optional(self, db: AsyncSession):
        mandate = await _mk_mandate(db)

        loaded = await _reload(db, mandate.id)

        assert loaded.origin_id is None
        assert loaded.origin_display_name is None


# ---------------------------------------------------------------------------
# TestAutoNomination
# ---------------------------------------------------------------------------


class TestAutoNomination:
    """Auto-désignation: mandatee = author, no candidacy steps needed."""

    @pytest.mark.asyncio
    async def test_auto_assign_author(self, db: AsyncSession):
        author = await _mk_identity(db, "Constance")
        mandate = await _mk_mandate(db, mandatee_id=author.id)

        loaded = await _reload(db, mandate.id)

        assert loaded.mandatee_id == author.id
        assert loaded.mandatee_display_name == "Constance"

    @pytest.mark.asyncio
    async def test_auto_assign_then_advance_to_active(self, db: AsyncSession):
        author = await _mk_identity(db, "David")
        mandate = await _mk_mandate(
            db,
            mandatee_id=author.id,
            steps=[
                {"step_type": "formulation", "status": "pending"},
                {"step_type": "assignment", "status": "pending"},
                {"step_type": "reporting", "status": "pending"},
            ],
        )

        # First advance: draft → candidacy, activates step 0
        result = await advance_mandate(mandate.id, db)
        assert result.status == "candidacy"

        loaded = await _reload(db, mandate.id)
        assert loaded.steps[0].status == "active"
        assert loaded.steps[1].status == "pending"

        # Second advance: step 0 → completed, step 1 → active
        await advance_mandate(mandate.id, db)
        loaded = await _reload(db, mandate.id)
        assert loaded.steps[0].status == "completed"
        assert loaded.steps[1].status == "active"


# ---------------------------------------------------------------------------
# TestMandateAssign
# ---------------------------------------------------------------------------


class TestMandateAssign:
    """assign_mandatee service: proper UUID lookup, display_name populated."""

    @pytest.mark.asyncio
    async def test_assign_sets_mandatee_and_starts_at(self, db: AsyncSession):
        identity = await _mk_identity(db, "Elodie")
        mandate = await _mk_mandate(db, status="active")

        await assign_mandatee(mandate.id, identity.id, db)

        loaded = await _reload(db, mandate.id)
        assert loaded.mandatee_id == identity.id
        assert loaded.starts_at is not None
        assert loaded.mandatee_display_name == "Elodie"

    @pytest.mark.asyncio
    async def test_assign_unknown_identity_raises(self, db: AsyncSession):
        mandate = await _mk_mandate(db, status="active")

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

    @pytest.mark.asyncio
    async def test_assign_completed_mandate_raises(self, db: AsyncSession):
        identity = await _mk_identity(db, "Fabien")
        mandate = await _mk_mandate(db, status="completed")

        with pytest.raises(ValueError, match="statut terminal"):
            await assign_mandatee(mandate.id, identity.id, db)

    @pytest.mark.asyncio
    async def test_reassign_replaces_mandatee(self, db: AsyncSession):
        first = await _mk_identity(db, "Gilles")
        second = await _mk_identity(db, "Hélène")
        mandate = await _mk_mandate(db, mandatee_id=first.id, status="active")

        await assign_mandatee(mandate.id, second.id, db)

        loaded = await _reload(db, mandate.id)
        assert loaded.mandatee_id == second.id


# ---------------------------------------------------------------------------
# TestMandateLifecycle
# ---------------------------------------------------------------------------


class TestMandateLifecycle:
    """advance_mandate: full lifecycle with and without steps."""

    @pytest.mark.asyncio
    async def test_full_lifecycle_no_steps(self, db: AsyncSession):
        mandate = await _mk_mandate(db)
        statuses = [mandate.status]

        for _ in range(10):
            m = await advance_mandate(mandate.id, db)
            statuses.append(m.status)
            if m.status == "completed":
                break

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

    @pytest.mark.asyncio
    async def test_steps_activate_in_order(self, db: AsyncSession):
        mandate = await _mk_mandate(
            db,
            steps=[
                {"step_type": "formulation", "status": "pending"},
                {"step_type": "candidacy", "status": "pending"},
                {"step_type": "vote", "status": "pending"},
            ],
        )

        # Advance 1: activates step 0, moves to candidacy
        await advance_mandate(mandate.id, db)
        loaded = await _reload(db, mandate.id)
        assert loaded.status == "candidacy"
        assert loaded.steps[0].status == "active"
        assert loaded.steps[1].status == "pending"

        # Advance 2: step 0 → completed, step 1 → active
        await advance_mandate(mandate.id, db)
        loaded = await _reload(db, mandate.id)
        assert loaded.steps[0].status == "completed"
        assert loaded.steps[1].status == "active"

        # Advance 3: step 1 → completed, step 2 → active
        await advance_mandate(mandate.id, db)
        loaded = await _reload(db, mandate.id)
        assert loaded.steps[1].status == "completed"
        assert loaded.steps[2].status == "active"

        # Advance 4: step 2 → completed, no more pending → advance mandate status
        await advance_mandate(mandate.id, db)
        loaded = await _reload(db, mandate.id)
        assert loaded.steps[2].status == "completed"
        assert loaded.status == "voting"

    @pytest.mark.asyncio
    async def test_advance_terminal_raises(self, db: AsyncSession):
        for terminal in ("completed", "revoked"):
            mandate = await _mk_mandate(db, status=terminal)
            with pytest.raises(ValueError, match="statut terminal"):
                await advance_mandate(mandate.id, db)


# ---------------------------------------------------------------------------
# TestMandateRevocation
# ---------------------------------------------------------------------------


class TestMandateRevocation:
    """revoke_mandate: active/pending steps cancelled, completed steps preserved."""

    @pytest.mark.asyncio
    async def test_revoke_cancels_active_and_pending(self, db: AsyncSession):
        mandate = await _mk_mandate(
            db,
            status="active",
            steps=[
                {"step_type": "formulation", "status": "completed"},
                {"step_type": "assignment", "status": "active"},
                {"step_type": "reporting", "status": "pending"},
            ],
        )

        await revoke_mandate(mandate.id, db)

        loaded = await _reload(db, mandate.id)
        assert loaded.status == "revoked"
        assert loaded.ends_at is not None
        assert loaded.steps[0].status == "completed"
        assert loaded.steps[1].status == "cancelled"
        assert loaded.steps[2].status == "cancelled"

    @pytest.mark.asyncio
    async def test_revoke_sets_ends_at(self, db: AsyncSession):
        mandate = await _mk_mandate(db, status="draft")

        await revoke_mandate(mandate.id, db)

        loaded = await _reload(db, mandate.id)
        assert loaded.ends_at is not None

    @pytest.mark.asyncio
    async def test_revoke_already_revoked_raises(self, db: AsyncSession):
        mandate = await _mk_mandate(db, status="revoked")

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


# ---------------------------------------------------------------------------
# TestNominationInteractions
# ---------------------------------------------------------------------------


class TestNominationInteractions:
    """Cross-process: nomination + assignment + lifecycle are consistent."""

    @pytest.mark.asyncio
    async def test_assign_then_advance_full_cycle(self, db: AsyncSession):
        """Assigning a mandatee then running the full lifecycle completes cleanly."""
        mandatee = await _mk_identity(db, "Isabelle")
        mandate = await _mk_mandate(
            db,
            steps=[
                {"step_type": "formulation", "status": "pending"},
                {"step_type": "assignment", "status": "pending"},
                {"step_type": "completion", "status": "pending"},
            ],
        )

        # Assign before starting
        await assign_mandatee(mandate.id, mandatee.id, db)

        # Run through all steps
        for _ in range(5):
            m = await advance_mandate(mandate.id, db)
            if m.status in ("completed", "revoked"):
                break

        loaded = await _reload(db, mandate.id)
        # All steps completed, mandate advanced beyond steps
        assert all(s.status == "completed" for s in loaded.steps)
        assert loaded.mandatee_id == mandatee.id

    @pytest.mark.asyncio
    async def test_revoke_after_assign_preserves_mandatee_id(self, db: AsyncSession):
        """Revoking a mandate keeps mandatee_id (for audit trail)."""
        mandatee = await _mk_identity(db, "Jacques")
        mandate = await _mk_mandate(db, mandatee_id=mandatee.id, status="active")

        await revoke_mandate(mandate.id, db)

        loaded = await _reload(db, mandate.id)
        assert loaded.status == "revoked"
        assert loaded.mandatee_id == mandatee.id

    @pytest.mark.asyncio
    async def test_origin_and_mandatee_can_differ(self, db: AsyncSession):
        """The person who proposed the mandate (origin) is different from the mandatee."""
        proposer = await _mk_identity(db, "Kim")
        mandatee = await _mk_identity(db, "Laurent")

        mandate = await _mk_mandate(db, origin_id=proposer.id)
        await assign_mandatee(mandate.id, mandatee.id, db)

        loaded = await _reload(db, mandate.id)
        assert loaded.origin_id == proposer.id
        assert loaded.mandatee_id == mandatee.id
        assert loaded.origin_display_name == "Kim"
        assert loaded.mandatee_display_name == "Laurent"