import random
import string

from playwright.sync_api import Page, expect


def _unique_currency_code(existing: set[str]) -> str:
    """Generate a unique three-letter code not present in *existing*."""
    alphabet = string.ascii_uppercase
    for _ in range(100):
        candidate = "".join(random.choices(alphabet, k=3))
        if candidate not in existing and candidate != "USD":
            return candidate
    raise AssertionError(
        "Unable to generate a unique currency code for the test run."
    )


def _metric_value(page: Page, element_id: str) -> int:
    locator = page.locator(f"#{element_id}")
    expect(locator).to_be_visible()
    return int(locator.inner_text().strip())


def _expect_feedback(page: Page, expected_text: str) -> None:
    page.wait_for_function(
        "expected => {"
        "  const el = document.getElementById('currency-form-feedback');"
        "  if (!el) return false;"
        "  const text = (el.textContent || '').trim();"
        "  return !el.classList.contains('hidden') && text === expected;"
        "}",
        arg=expected_text,
    )
    feedback = page.locator("#currency-form-feedback")
    expect(feedback).to_have_text(expected_text)


def test_currency_workflow_create_update_toggle(page: Page) -> None:
    """Exercise create, update, and toggle flows on the currency settings page."""
    page.goto("/ui/currencies")
    expect(page).to_have_title("Currencies · CalMiner")
    expect(page.locator("h2:has-text('Currency Overview')")).to_be_visible()

    code_cells = page.locator("#currencies-table-body tr td:nth-child(1)")
    existing_codes = {
        text.strip().upper() for text in code_cells.all_inner_texts()
    }

    total_before = _metric_value(page, "currency-metric-total")
    active_before = _metric_value(page, "currency-metric-active")
    inactive_before = _metric_value(page, "currency-metric-inactive")

    new_code = _unique_currency_code(existing_codes)
    new_name = f"Test Currency {new_code}"
    new_symbol = new_code[0]

    page.fill("#currency-form-code", new_code)
    page.fill("#currency-form-name", new_name)
    page.fill("#currency-form-symbol", new_symbol)
    page.select_option("#currency-form-status", "true")

    with page.expect_response("**/api/currencies/") as create_info:
        page.click("button[type='submit']")
    create_response = create_info.value
    assert create_response.status == 201

    _expect_feedback(page, "Currency created successfully.")

    page.wait_for_function(
        "expected => Number(document.getElementById('currency-metric-total').textContent.trim()) === expected",
        arg=total_before + 1,
    )
    page.wait_for_function(
        "expected => Number(document.getElementById('currency-metric-active').textContent.trim()) === expected",
        arg=active_before + 1,
    )

    row = page.locator("#currencies-table-body tr").filter(has_text=new_code)
    expect(row).to_be_visible()
    expect(row.locator("td").nth(3)).to_have_text("Active")

    # Switch to update mode using the existing currency option.
    page.select_option("#currency-form-existing", new_code)
    updated_name = f"{new_name} Updated"
    updated_symbol = f"{new_symbol}$"
    page.fill("#currency-form-name", updated_name)
    page.fill("#currency-form-symbol", updated_symbol)
    page.select_option("#currency-form-status", "false")

    with page.expect_response(f"**/api/currencies/{new_code}") as update_info:
        page.click("button[type='submit']")
    update_response = update_info.value
    assert update_response.status == 200

    _expect_feedback(page, "Currency updated successfully.")

    page.wait_for_function(
        "expected => Number(document.getElementById('currency-metric-active').textContent.trim()) === expected",
        arg=active_before,
    )
    page.wait_for_function(
        "expected => Number(document.getElementById('currency-metric-inactive').textContent.trim()) === expected",
        arg=inactive_before + 1,
    )

    expect(row.locator("td").nth(1)).to_have_text(updated_name)
    expect(row.locator("td").nth(2)).to_have_text(updated_symbol)
    expect(row.locator("td").nth(3)).to_contain_text("Inactive")

    toggle_button = row.locator("button[data-action='toggle']")
    expect(toggle_button).to_have_text("Activate")

    with page.expect_response(
        f"**/api/currencies/{new_code}/activation"
    ) as toggle_info:
        toggle_button.click()
    toggle_response = toggle_info.value
    assert toggle_response.status == 200

    page.wait_for_function(
        "expected => Number(document.getElementById('currency-metric-active').textContent.trim()) === expected",
        arg=active_before + 1,
    )
    page.wait_for_function(
        "expected => Number(document.getElementById('currency-metric-inactive').textContent.trim()) === expected",
        arg=inactive_before,
    )

    _expect_feedback(page, f"Currency {new_code} activated.")

    expect(row.locator("td").nth(3)).to_contain_text("Active")
    expect(row.locator("button[data-action='toggle']")).to_have_text(
        "Deactivate"
    )