package main

import (
	"crypto/sha256"
	"encoding/hex"
	"os"
	"path/filepath"
	"strings"
	"testing"
)

// miniDump is a twelve-page stand-in for the Wikimedia dump, committed
// compressed beside its readable source. Go has no bzip2 writer, so the .bz2
// is regenerated by hand: bzip2 -k9 testdata/mini-dump.xml.
const miniDump = "testdata/mini-dump.xml.bz2"

// miniDumpCut is the same XML cut mid-page and then compressed: a valid bzip2
// stream whose XML ends early, as distinct from a truncated download.
const miniDumpCut = "testdata/mini-dump-cut.xml.bz2"

func TestReadDumpKeepsVietnameseSections(t *testing.T) {
	words, meanings, rejects, stats, prov, err := readDump(miniDump)
	if err != nil {
		t.Fatal(err)
	}

	var got []string
	for w := range words {
		got = append(got, w)
	}
	assertSameStrings(t, got, []string{"pháp luật", "hòa bình", "luật lệ", "ngôn ngữ", "ngữ pháp", "vô tuyến điện"})

	if stats.pages != 12 || stats.ns0 != 11 || stats.redirects != 1 || stats.noVietnamese != 1 {
		t.Errorf("pages %d ns0 %d redirects %d noVietnamese %d, want 12 11 1 1",
			stats.pages, stats.ns0, stats.redirects, stats.noVietnamese)
	}
	if stats.legacy != 7 || stats.newDialect != 2 || stats.bothDialects != 0 {
		t.Errorf("legacy %d new %d both %d, want 7 2 0", stats.legacy, stats.newDialect, stats.bothDialects)
	}
	if prov.pages != 9 {
		t.Errorf("source pages = %d, want 9 (Vietnamese sections, redirect excluded)", prov.pages)
	}
	if stats.merged != 1 {
		t.Errorf("merged = %d, want 1 (Hòa Bình and hòa bình)", stats.merged)
	}
	if rejects[rejectNotVietnamese] != 1 || rejects[rejectTooShort] != 1 || rejects[rejectDigit] != 1 {
		t.Errorf("rejects = %v, want one each of not-Vietnamese, too-short, digit", rejects)
	}

	assertSenses(t, meanings["pháp luật"], []sense{
		{"danh từ", "Hệ thống các quy tắc xử sự do nhà nước đặt ra."},
		{"danh từ", "(nghĩa rộng) Kỷ cương nói chung."},
		{"động từ", "(hiếm) Xử theo luật."},
	})
	// Capitalized page first, lowercase page second: senses in page order,
	// the new-dialect place first.
	assertSenses(t, meanings["hòa bình"], []sense{
		{"danh từ riêng", "tỉnh, Việt Nam."},
		{"danh từ", "Tình trạng không có chiến tranh."},
		{"tính từ", "Yên ổn."},
	})
	assertSenses(t, meanings["ngôn ngữ"], []sense{{"danh từ", "Hệ thống những âm, từ và quy tắc kết hợp chúng."}})
	if _, has := meanings["luật lệ"]; has {
		t.Error("a definition that is only an unknown template produced a sense")
	}
	if stats.section.dropped["rfdef"] != 1 || stats.section.defsEmpty != 1 {
		t.Errorf("dropped = %v empty = %d, want rfdef 1 and 1", stats.section.dropped, stats.section.defsEmpty)
	}
	if stats.section.pos["noun"] == 0 || stats.section.pos["pr-noun"] != 2 || stats.section.pos["n"] != 1 {
		t.Errorf("pos tally = %v", stats.section.pos)
	}
}

func TestReadDumpHashesTheBytesItRead(t *testing.T) {
	_, _, _, _, prov, err := readDump(miniDump)
	if err != nil {
		t.Fatal(err)
	}
	raw, err := os.ReadFile(miniDump)
	if err != nil {
		t.Fatal(err)
	}
	sum := sha256.Sum256(raw)
	if prov.sha256 != hex.EncodeToString(sum[:]) {
		t.Errorf("sha256 = %s, want %s (the whole file)", prov.sha256, hex.EncodeToString(sum[:]))
	}
	if prov.fetchedAt.IsZero() {
		t.Error("fetchedAt is zero")
	}
}

func TestReadDumpRejectsNonBzip2(t *testing.T) {
	path := filepath.Join(t.TempDir(), "dump.xml.bz2")
	if err := os.WriteFile(path, []byte("<mediawiki></mediawiki>"), 0o644); err != nil {
		t.Fatal(err)
	}
	_, _, _, _, _, err := readDump(path)
	if err == nil || !strings.Contains(err.Error(), "not a bzip2 file") {
		t.Fatalf("err = %v, want a message naming the missing bzip2 header", err)
	}
}

func TestReadDumpRejectsTruncatedDownload(t *testing.T) {
	raw, err := os.ReadFile(miniDump)
	if err != nil {
		t.Fatal(err)
	}
	path := filepath.Join(t.TempDir(), "dump.xml.bz2")
	if err := os.WriteFile(path, raw[:len(raw)/2], 0o644); err != nil {
		t.Fatal(err)
	}
	_, _, _, _, _, err = readDump(path)
	if err == nil {
		t.Fatal("a half-downloaded dump was read without error")
	}
	if !strings.Contains(err.Error(), "truncated") {
		t.Errorf("err = %v, want it to suggest a truncated download", err)
	}
}

func TestReadDumpRejectsStreamEndingMidPage(t *testing.T) {
	_, _, _, _, _, err := readDump(miniDumpCut)
	if err == nil {
		t.Fatal("an XML stream ending mid-page was read without error")
	}
	if !strings.Contains(err.Error(), `after page "hello world"`) {
		t.Errorf("err = %v, want it to name the last page fully read", err)
	}
}

func TestRunFailsBelowMinPages(t *testing.T) {
	cfg := config{
		dump:     miniDump,
		out:      filepath.Join(t.TempDir(), "noitu.db"),
		minWords: 1,
		minPages: 20000,
	}
	err := run(cfg)
	if err == nil || !strings.Contains(err.Error(), "pages have a Vietnamese section") {
		t.Fatalf("err = %v, want the page floor named", err)
	}
}

func TestFormatTally(t *testing.T) {
	got := formatTally(map[string]int{"b": 2, "a": 2, "": 5, "c": 1}, 3)
	if want := "(none) 5, a 2, b 2"; got != want {
		t.Errorf("formatTally = %q, want %q", got, want)
	}
}