from __future__ import annotations

import sqlite3

import pytest

from jarca_ledger_mcp.application.monthly_settlement_service import (
    create_monthly_settlement,
    link_account_snapshot,
    list_account_snapshots_for_settlement,
)
from jarca_ledger_mcp.infrastructure.sqlite.migrations import init_db


def _account(conn, ident="acct-1", name="실제계정", currency="KRW"):
    conn.execute(
        "INSERT INTO accounts(id,name,currency,created_at,updated_at) VALUES(?,?,?,?,?)",
        (ident, name, currency, "2026-10-01T00:00:00Z", "2026-10-01T00:00:00Z"),
    )


def _snapshot(conn, ident, *, account="acct-1", basis_date="2026-10-31", currency="KRW", settlement=None, amount=1234):
    conn.execute(
        """INSERT INTO account_snapshot
        (id,basis_date,source_type,source_id,name,amount,currency,liquidity_bucket,
         monthly_settlement_id,valuation_id,verification_status,created_at)
        VALUES(?,?,?,?,?,?,?,?,?,?,?,?)""",
        (ident, basis_date, "account", account, "원본 스냅샷명", amount, currency, "cash", settlement,
         "valuation-1", "unverified", "2026-10-31T00:00:00Z"),
    )


def _ledger(tmp_path):
    path = tmp_path / "link.sqlite3"
    init_db(str(path))
    with sqlite3.connect(path) as conn:
        draft = create_monthly_settlement("2026-10", db_path=str(path))["settlement_id"]
        conn.execute("UPDATE monthly_settlement SET basis_date='2026-10-31' WHERE id=?", (draft,))
        _account(conn)
        conn.commit()
    return path, draft


def test_link_updates_only_monthly_fk_and_preserves_snapshot_fields(tmp_path):
    path, settlement = _ledger(tmp_path)
    with sqlite3.connect(path) as conn:
        _snapshot(conn, "candidate")
        before = conn.execute("SELECT * FROM account_snapshot WHERE id='candidate'").fetchone()
        columns = [row[1] for row in conn.execute("PRAGMA table_info(account_snapshot)")]
    result = link_account_snapshot("candidate", settlement, db_path=str(path))
    assert result["success"] is True
    with sqlite3.connect(path) as conn:
        after = conn.execute("SELECT * FROM account_snapshot WHERE id='candidate'").fetchone()
    assert len(before) == len(after) == len(columns)
    changed = {column: (old, new) for column, old, new in zip(columns, before, after) if old != new}
    assert changed == {"monthly_settlement_id": (None, settlement)}


def test_actual_read_function_returns_unlinked_candidates_in_exact_order(tmp_path):
    path, settlement = _ledger(tmp_path)
    with sqlite3.connect(path) as conn:
        _snapshot(conn, "old", basis_date="2026-09-30", amount=1)
        _snapshot(conn, "exact-old-created", basis_date="2026-10-31", amount=2)
        _snapshot(conn, "exact-new-created", basis_date="2026-10-31", amount=3)
        conn.execute("UPDATE account_snapshot SET created_at='2026-10-31T02:00:00Z' WHERE id='exact-old-created'")
        conn.execute("UPDATE account_snapshot SET created_at='2026-10-31T03:00:00Z' WHERE id='exact-new-created'")
        conn.commit()
    result = list_account_snapshots_for_settlement(settlement, db_path=str(path))
    row = result["snapshots"][0]
    assert [item["snapshot_id"] for item in row["unlinked_candidates"]] == ["exact-new-created", "exact-old-created", "old"]

@pytest.mark.parametrize("status", ["approved", "closed"])
def test_link_rejects_approved_and_closed(tmp_path, status):
    path, settlement = _ledger(tmp_path)
    with sqlite3.connect(path) as conn:
        _snapshot(conn, "candidate")
        conn.execute("""UPDATE monthly_settlement SET status=?, approved_by='test',
            approved_at='2026-10-31T00:00:00Z', approved_version=1,
            approved_fingerprint='test', closed_by='test', closed_at='2026-10-31T00:00:00Z' WHERE id=?""", (status, settlement))
        conn.commit()
    result = link_account_snapshot("candidate", settlement, db_path=str(path))
    assert result["success"] is False
    assert result["error_code"] == "invalid_settlement_status"


def test_link_rejects_unrelated_month_and_already_linked_snapshot(tmp_path):
    path, settlement = _ledger(tmp_path)
    with sqlite3.connect(path) as conn:
        other = create_monthly_settlement("2026-11", db_path=str(path))["settlement_id"]
        _snapshot(conn, "linked-other", settlement=other)
        _snapshot(conn, "linked-this", settlement=settlement)
        conn.commit()
    assert link_account_snapshot("linked-other", settlement, db_path=str(path))["error_code"] == "already_linked"
    assert link_account_snapshot("linked-this", settlement, db_path=str(path))["error_code"] == "already_linked"


def test_basis_date_mismatch_requires_explicit_true(tmp_path):
    path, settlement = _ledger(tmp_path)
    with sqlite3.connect(path) as conn:
        _snapshot(conn, "mismatch", basis_date="2026-09-30")
        conn.commit()
    rejected = link_account_snapshot("mismatch", settlement, db_path=str(path))
    assert rejected["error_code"] == "basis_date_mismatch"
    accepted = link_account_snapshot("mismatch", settlement, allow_basis_date_mismatch=True, db_path=str(path))
    assert accepted["success"] is True


def test_link_rejects_account_currency_mismatch(tmp_path):
    path, settlement = _ledger(tmp_path)
    with sqlite3.connect(path) as conn:
        _snapshot(conn, "bad-currency", currency="USD")
        conn.commit()
    result = link_account_snapshot("bad-currency", settlement, db_path=str(path))
    assert result["error_code"] == "validation_error"