from types import SimpleNamespace
from sqlalchemy.dialects import sqlite

from app.services.customers_search import (
    apply_customer_filters,
    apply_customer_sorting,
    prepare_customer_csv_rows,
)


class FakeQuery:
    """Lightweight stand-in for SQLAlchemy Query that captures filters and orderings.

    We only need to verify that our helper functions add the expected number of
    filter/order_by clauses and roughly target the expected columns. We do not
    execute any SQL.
    """

    def __init__(self):
        self.filters = []
        self.orderings = []

    def filter(self, *args):
        self.filters.extend(args)
        return self

    def order_by(self, *args):
        self.orderings.extend(args)
        return self


def compile_sql(expr):
    """Compile a SQLAlchemy expression to a SQLite SQL string for simple assertions."""
    try:
        return str(expr.compile(dialect=sqlite.dialect()))
    except Exception:
        return str(expr)


def test_apply_customer_filters_search_and_comma_pattern():
    q = FakeQuery()
    q = apply_customer_filters(q, search="Smith, John", group=None, state=None, groups=None, states=None)
    # One filter clause added (combined search filter)
    assert len(q.filters) == 1
    sql = compile_sql(q.filters[0])
    assert "last" in sql and "first" in sql


def test_apply_customer_filters_groups_and_states():
    q = FakeQuery()
    q = apply_customer_filters(q, search=None, group="A", state="NY", groups=None, states=None)
    # Two filter clauses added: group and state
    assert len(q.filters) == 2
    sql_group = compile_sql(q.filters[0])
    sql_state = compile_sql(q.filters[1])
    assert "group" in sql_group
    assert "abrev" in sql_state or "state" in sql_state


def test_apply_customer_filters_multi_groups_priority():
    q = FakeQuery()
    q = apply_customer_filters(q, search=None, group="A", state=None, groups=["X", "Y"], states=None)
    # Only one filter (multi-groups) should be applied for groups
    assert len(q.filters) == 1
    assert "IN" in compile_sql(q.filters[0])


def test_apply_customer_sorting_fields_and_direction():
    # name sorting => two orderings
    q1 = FakeQuery()
    q1 = apply_customer_sorting(q1, sort_by="name", sort_dir="asc")
    assert len(q1.orderings) == 2
    assert "last" in compile_sql(q1.orderings[0])
    assert "first" in compile_sql(q1.orderings[1])

    # id sorting desc => one ordering and DESC direction in SQL
    q2 = FakeQuery()
    q2 = apply_customer_sorting(q2, sort_by="id", sort_dir="desc")
    assert len(q2.orderings) == 1
    assert "DESC" in compile_sql(q2.orderings[0]).upper()

    # unknown field falls back to id
    q3 = FakeQuery()
    q3 = apply_customer_sorting(q3, sort_by="unknown", sort_dir="asc")
    assert len(q3.orderings) == 1
    assert "id" in compile_sql(q3.orderings[0]).lower()


def test_prepare_customer_csv_rows_default_and_selected_fields():
    cust1 = SimpleNamespace(
        id="001",
        first="John",
        last="Smith",
        group="G1",
        city="New York",
        abrev="NY",
        email="john@example.com",
        phone_numbers=[SimpleNamespace(phone="123-456-7890")],
    )
    cust2 = SimpleNamespace(
        id="002",
        first="Jane",
        last="Doe",
        group="G2",
        city="Boston",
        abrev="MA",
        email="jane@example.com",
        phone_numbers=[],
    )

    # Default fields
    header, rows = prepare_customer_csv_rows([cust1, cust2], fields=None)
    assert header == [
        "Customer ID",
        "Name",
        "Group",
        "City",
        "State",
        "Primary Phone",
        "Email",
    ]
    assert rows[0][0] == "001"
    assert rows[0][1] == "John Smith"
    assert rows[0][2] == "G1"
    assert rows[0][3] == "New York"
    assert rows[0][4] == "NY"
    assert rows[0][5] == "123-456-7890"
    assert rows[0][6] == "john@example.com"

    # Selected subset of fields
    header_sel, rows_sel = prepare_customer_csv_rows([cust1], fields=["id", "name", "email"])  # any case ok
    assert header_sel == ["Customer ID", "Name", "Email"]
    assert rows_sel[0] == ["001", "John Smith", "john@example.com"]