package fio

import (
	"context"
	"io"
	"net/http"
	"net/http/httptest"
	"os"
	"testing"
	"time"
)

func TestAPIClient_ParseResponse(t *testing.T) {
	body, err := os.ReadFile("testdata/api_response.json")
	if err != nil {
		t.Fatal(err)
	}
	txns, err := parseAPIResponse(body)
	if err != nil {
		t.Fatal(err)
	}
	if len(txns) != 1 {
		t.Fatalf("want 1 txn (outgoing filtered), got %d", len(txns))
	}
	tx := txns[0]
	if tx.Date != "2026-04-10" {
		t.Errorf("date: want '2026-04-10', got %q", tx.Date)
	}
	if tx.Amount != 750 {
		t.Errorf("amount: want 750, got %v", tx.Amount)
	}
	if tx.Sender != "Jana Novakova" {
		t.Errorf("sender: want 'Jana Novakova', got %q", tx.Sender)
	}
	if tx.Message != "duben 2026" {
		t.Errorf("message: want 'duben 2026', got %q", tx.Message)
	}
	if tx.VS != "123" {
		t.Errorf("vs: want '123', got %q", tx.VS)
	}
	if tx.BankID != "12345678901" {
		t.Errorf("bank_id: want '12345678901', got %q", tx.BankID)
	}
}

func TestAPIClient_HTTPRoundTrip(t *testing.T) {
	body, _ := os.ReadFile("testdata/api_response.json")
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
		_, _ = w.Write(body)
	}))
	defer srv.Close()

	c := &apiClient{token: "TESTTOKEN", hc: &overrideClient{base: srv.Client(), baseURL: srv.URL}}
	txns, err := c.FetchTransactions(context.Background(), time.Now().AddDate(0, -1, 0), time.Now())
	if err != nil {
		t.Fatal(err)
	}
	if len(txns) != 1 {
		t.Fatalf("want 1 txn, got %d", len(txns))
	}
}

func TestTransparentClient_ParseHTML(t *testing.T) {
	body, err := os.ReadFile("testdata/transparent.html")
	if err != nil {
		t.Fatal(err)
	}
	txns, err := parseTransparentHTML(body)
	if err != nil {
		t.Fatal(err)
	}
	// Only the incoming row (750 CZK) should be kept; -200 is outgoing
	if len(txns) != 1 {
		t.Fatalf("want 1 txn (outgoing filtered), got %d", len(txns))
	}
	tx := txns[0]
	if tx.Date != "2026-04-10" {
		t.Errorf("date: want '2026-04-10', got %q", tx.Date)
	}
	if tx.Amount != 750 {
		t.Errorf("amount: want 750, got %v", tx.Amount)
	}
	if tx.Sender != "Jana Novakova" {
		t.Errorf("sender: want 'Jana Novakova', got %q", tx.Sender)
	}
	if tx.VS != "123" {
		t.Errorf("vs: want '123', got %q", tx.VS)
	}
	if tx.BankID != "" {
		t.Errorf("bank_id: want empty on HTML path, got %q", tx.BankID)
	}
}

func TestParseCzechDate(t *testing.T) {
	cases := []struct{ in, want string }{
		{"10.04.2026", "2026-04-10"},
		{"10/04/2026", "2026-04-10"},
		{"7.5.2026", "2026-05-07"},  // non-padded — real Fio transparent page format
		{"3.12.2025", "2025-12-03"}, // non-padded single-digit day, double-digit month
		{"07.05.26", "2026-05-07"},  // padded 2-digit year — current Fio transparent page format
		{"7.5.26", "2026-05-07"},    // non-padded 2-digit year
		{"07/05/26", "2026-05-07"},  // slash variant
		{"", ""},
		{"invalid", ""},
	}
	for _, c := range cases {
		if got := parseCzechDate(c.in); got != c.want {
			t.Errorf("parseCzechDate(%q) = %q, want %q", c.in, got, c.want)
		}
	}
}

func TestExtractSecondTableRows_NestedTable(t *testing.T) {
	// Regression: a nested <table> inside the target must not cause early exit.
	html := `<table class="table"><tr><td>nav</td></tr></table>
<table class="table">
  <thead><tr><th>Date</th></tr></thead>
  <tbody>
    <tr><td>7.5.2026</td><td><table><tr><td>nested</td></tr></table></td></tr>
    <tr><td>6.5.2026</td><td></td></tr>
  </tbody>
</table>`
	rows := extractSecondTableRows([]byte(html))
	if len(rows) != 2 {
		t.Errorf("want 2 data rows, got %d: %v", len(rows), rows)
	}
}

func TestParseCzechAmount(t *testing.T) {
	cases := []struct {
		in   string
		want float64
	}{
		{"750,00 CZK", 750},
		{"1.500,00", 1500},
		{"1500.00", 1500},
		{"-200,00 CZK", -200},
	}
	for _, c := range cases {
		if got := parseCzechAmount(c.in); got != c.want {
			t.Errorf("parseCzechAmount(%q) = %v, want %v", c.in, got, c.want)
		}
	}
}

func TestFake(t *testing.T) {
	f := &Fake{Transactions: []Transaction{{Date: "2026-04-01", Amount: 500}}}
	txns, err := f.FetchTransactions(context.Background(), time.Now(), time.Now())
	if err != nil {
		t.Fatal(err)
	}
	if len(txns) != 1 || txns[0].Date != "2026-04-01" {
		t.Errorf("unexpected: %v", txns)
	}
}

// overrideClient replaces the URL in requests so we can hit a local test server
// instead of the real Fio URL.
type overrideClient struct {
	base    *http.Client
	baseURL string
}

func (o *overrideClient) Do(req *http.Request) (*http.Response, error) {
	r2, _ := http.NewRequestWithContext(req.Context(), req.Method, o.baseURL+req.URL.Path, nil)
	resp, err := o.base.Do(r2)
	if err != nil {
		return nil, err
	}
	// The api client reads the body, so re-serve whatever the test server returned.
	return resp, nil
}

// verify Fake satisfies Client
var _ Client = (*Fake)(nil)

// ensure io.ReadAll isn't called at top level (compile-time reference suppressor)
var _ = io.ReadAll