package html_test

import (
	"bytes"
	"strings"
	"testing"
	"time"

	"github.com/nmoniz/any2anexoj/internal"
	"github.com/nmoniz/any2anexoj/internal/writing"
	htmlwriter "github.com/nmoniz/any2anexoj/internal/writing/html"
	"github.com/shopspring/decimal"
)

// buildTestAggregator returns an AggregatorWriter seeded with two
// deterministic ReportItems so every test can assert on a stable document
// shape. Mirrors the fixture pattern used in
// internal/writing/table/printer_test.go.
func buildTestAggregator(t *testing.T) *internal.AggregatorWriter {
	t.Helper()
	aw := internal.NewAggregatorWriter()
	ctx := t.Context()

	err := aw.Write(ctx, internal.ReportItem{
		Symbol:        "AAPL",
		Nature:        internal.NatureG01,
		BrokerCountry: 826,
		AssetCountry:  840,
		BuyValue:      decimal.NewFromFloat(100.50),
		BuyTimestamp:  time.Date(2023, 1, 15, 0, 0, 0, 0, time.UTC),
		SellValue:     decimal.NewFromFloat(150.75),
		SellTimestamp: time.Date(2023, 6, 20, 0, 0, 0, 0, time.UTC),
		Fees:          decimal.NewFromFloat(2.50),
		Taxes:         decimal.NewFromFloat(5.00),
	})
	if err != nil {
		t.Fatalf("failed to write first report item: %v", err)
	}

	err = aw.Write(ctx, internal.ReportItem{
		Symbol:        "GOOGL",
		Nature:        internal.NatureG20,
		BrokerCountry: 826,
		AssetCountry:  840,
		BuyValue:      decimal.NewFromFloat(200.00),
		BuyTimestamp:  time.Date(2023, 3, 10, 0, 0, 0, 0, time.UTC),
		SellValue:     decimal.NewFromFloat(225.50),
		SellTimestamp: time.Date(2023, 9, 5, 0, 0, 0, 0, time.UTC),
		Fees:          decimal.NewFromFloat(3.00),
		Taxes:         decimal.NewFromFloat(7.50),
	})
	if err != nil {
		t.Fatalf("failed to write second report item: %v", err)
	}

	return aw
}

func TestWriter_Render(t *testing.T) {
	loc, err := writing.NewLocalizer("en")
	if err != nil {
		t.Fatalf("create localizer: %v", err)
	}

	var buf bytes.Buffer
	hw := htmlwriter.NewWriter(&buf, loc, "en")

	if err := hw.Render(buildTestAggregator(t)); err != nil {
		t.Fatalf("Render returned an error: %v", err)
	}

	got := buf.String()

	wantSubstrings := []string{
		"<!DOCTYPE html>",
		`<html lang="en">`,
		`<meta charset="utf-8">`,
		`<meta name="viewport" content="width=device-width, initial-scale=1">`,
		`<title>Tax report</title>`,
		`<style>`,
		`Bootstrap  v5.3.3`,
		`<main class="container-fluid py-4">`,
		`<h1>Tax report</h1>`,
		`<div class="table-responsive">`,
		`<table class="table table-striped table-hover table-bordered" style="table-layout: fixed">`,
		`<colgroup>`,
		`</table>`,
		`<tfoot>`,
		`</tfoot>`,
		`</html>`,
		`<p class="text-muted small">Generated at `,
	}
	for _, s := range wantSubstrings {
		if !strings.Contains(got, s) {
			t.Errorf("rendered HTML missing expected substring %q\nGot:\n%s", s, got)
		}
	}

	// The table fragment must be embedded as raw HTML, not escaped.
	if strings.Contains(got, "&lt;table") {
		t.Errorf("table fragment appears to be HTML-escaped; expected raw <table> markup\nGot:\n%s", got)
	}
	if !strings.Contains(got, "<table") {
		t.Errorf("expected raw <table> tag in output\nGot:\n%s", got)
	}

	// The document must be fully self-contained: no external stylesheet
	// <link> and no CDN reference anywhere.
	if strings.Contains(got, "<link") {
		t.Errorf("expected no external stylesheet <link>; document must be self-contained\nGot:\n%s", got)
	}
	if strings.Contains(got, "cdn.jsdelivr.net") {
		t.Errorf("expected no CDN references; document must be self-contained\nGot:\n%s", got)
	}

	// Generated timestamp must be valid RFC3339 UTC.
	startIdx := strings.Index(got, "Generated at ")
	if startIdx == -1 {
		t.Fatalf("missing 'Generated at' prefix in output")
	}
	timestampLine := got[startIdx:]
	endIdx := strings.Index(timestampLine, "</p>")
	if endIdx == -1 {
		t.Fatalf("missing </p> closing tag after 'Generated at' line")
	}
	timestampStr := strings.TrimPrefix(strings.SplitN(timestampLine, "</p>", 2)[0], "Generated at ")
	if _, err := time.Parse(time.RFC3339, timestampStr); err != nil {
		t.Errorf("generation timestamp is not valid RFC3339: %q (err: %v)", timestampStr, err)
	}
}

// TestWriter_NoRowDuplication verifies that calling Render twice on the
// same writer produces documents with the same number of <tr> rows, just
// like table.Printer's no-duplication guarantee.
func TestWriter_NoRowDuplication(t *testing.T) {
	loc, err := writing.NewLocalizer("en")
	if err != nil {
		t.Fatalf("create localizer: %v", err)
	}

	var buf bytes.Buffer
	hw := htmlwriter.NewWriter(&buf, loc, "en")

	aw := buildTestAggregator(t)

	if err := hw.Render(aw); err != nil {
		t.Fatalf("first Render returned an error: %v", err)
	}
	first := buf.String()
	buf.Reset()

	if err := hw.Render(aw); err != nil {
		t.Fatalf("second Render returned an error: %v", err)
	}
	second := buf.String()

	firstRows := strings.Count(first, "<tr")
	secondRows := strings.Count(second, "<tr")
	if firstRows == 0 {
		t.Fatalf("expected at least one <tr> row in the first render; got:\n%s", first)
	}
	if firstRows != secondRows {
		t.Errorf("expected second Render to produce the same number of <tr> rows as the first (no duplication)\nfirst rows=%d, second rows=%d\nFirst:\n%s\nSecond:\n%s",
			firstRows, secondRows, first, second)
	}
}

func TestWriter_LangAttribute(t *testing.T) {
	loc, err := writing.NewLocalizer("pt")
	if err != nil {
		t.Fatalf("create localizer: %v", err)
	}

	var buf bytes.Buffer
	hw := htmlwriter.NewWriter(&buf, loc, "pt")

	if err := hw.Render(buildTestAggregator(t)); err != nil {
		t.Fatalf("Render returned an error: %v", err)
	}

	got := buf.String()
	if !strings.Contains(got, `<html lang="pt">`) {
		t.Errorf("expected <html lang=\"pt\"> attribute; got:\n%s", got)
	}
	if !strings.Contains(got, `<h1>Relatório fiscal</h1>`) {
		t.Errorf("expected Portuguese title in <h1>; got:\n%s", got)
	}
}