package web

import (
	"bytes"
	"mime/multipart"
	"net/http"
	"net/http/httptest"
	"os"
	"path/filepath"
	"strconv"
	"strings"
	"testing"

	"maisym.com/hsa/internal/auth"
	"maisym.com/hsa/internal/config"
	"maisym.com/hsa/internal/storage"
)

func testServerWithStore(t *testing.T) *Server {
	t.Helper()
	var key [32]byte
	copy(key[:], "web-test-key-32-bytes-padded!!!!")
	store, err := storage.Open(filepath.Join(t.TempDir(), "test.db"))
	if err != nil {
		t.Fatal(err)
	}
	t.Cleanup(func() { store.Close() })
	return &Server{
		cfg: config.Config{
			SessionKey:     key,
			RequiredGroup:  "hsa-users",
			StorageDir:     filepath.Join(t.TempDir(), "files"),
			MaxUploadBytes: 32 << 20,
		},
		store: store,
	}
}

func authCookie(t *testing.T, s *Server) *http.Cookie {
	t.Helper()
	sess := auth.Session{Subject: "jm@example.com", Groups: []string{"hsa-users"}}
	v, err := auth.EncodeSession(sess, s.cfg.SessionKey)
	if err != nil {
		t.Fatal(err)
	}
	return &http.Cookie{Name: sessionCookie, Value: v}
}

// aCategoryID returns the id of a seeded category as a string.
func aCategoryID(t *testing.T, s *Server) string {
	t.Helper()
	cats, err := s.store.ListCategories()
	if err != nil || len(cats) == 0 {
		t.Fatalf("ListCategories: %v", err)
	}
	return strconv.FormatInt(cats[0].ID, 10)
}

// fakePNG returns bytes that http.DetectContentType recognises as image/png.
func fakePNG() []byte {
	return append([]byte("\x89PNG\r\n\x1a\n"), []byte("fake-image-content")...)
}

func multipartUpload(t *testing.T, fields map[string]string, fileField, fileName string, fileData []byte) (*bytes.Buffer, string) {
	t.Helper()
	var body bytes.Buffer
	mw := multipart.NewWriter(&body)
	for k, v := range fields {
		_ = mw.WriteField(k, v)
	}
	if fileData != nil {
		fw, err := mw.CreateFormFile(fileField, fileName)
		if err != nil {
			t.Fatal(err)
		}
		fw.Write(fileData)
	}
	mw.Close()
	return &body, mw.FormDataContentType()
}

func TestUpload_HappyPath_WritesFileAndRow(t *testing.T) {
	s := testServerWithStore(t)
	body, ct := multipartUpload(t,
		map[string]string{"amount": "12.34", "receipt_date": "2026-06-01", "category_id": aCategoryID(t, s)},
		"receipt", "receipt.png", fakePNG())

	req := httptest.NewRequest(http.MethodPost, "/upload", body)
	req.Header.Set("Content-Type", ct)
	req.AddCookie(authCookie(t, s))
	rec := httptest.NewRecorder()
	s.Routes().ServeHTTP(rec, req)

	if rec.Code != http.StatusOK {
		t.Fatalf("status = %d, want 200; body=%s", rec.Code, rec.Body.String())
	}
	if !strings.Contains(rec.Body.String(), "Receipt saved") {
		t.Errorf("missing confirmation: %s", rec.Body.String())
	}

	// Row written.
	n, err := s.store.CountActive()
	if err != nil {
		t.Fatal(err)
	}
	if n != 1 {
		t.Fatalf("CountActive = %d, want 1", n)
	}

	// File written to disk under the receipt-year subdir with a dated, amount-
	// tagged name (date 2026-06-01, amount 12.34 -> 2026/06_01_12.34.png).
	entries, err := os.ReadDir(filepath.Join(s.cfg.StorageDir, "2026"))
	if err != nil {
		t.Fatal(err)
	}
	if len(entries) != 1 {
		t.Fatalf("year dir has %d files, want 1", len(entries))
	}
	if entries[0].Name() != "06_01_12.34.png" {
		t.Errorf("stored file name = %q, want 06_01_12.34.png", entries[0].Name())
	}
}

func TestUpload_SameDateAmount_DisambiguatesFilename(t *testing.T) {
	s := testServerWithStore(t)
	cat := aCategoryID(t, s)
	post := func() {
		body, ct := multipartUpload(t,
			map[string]string{"amount": "12.34", "receipt_date": "2026-06-01", "category_id": cat},
			"receipt", "receipt.png", fakePNG())
		req := httptest.NewRequest(http.MethodPost, "/upload", body)
		req.Header.Set("Content-Type", ct)
		req.AddCookie(authCookie(t, s))
		rec := httptest.NewRecorder()
		s.Routes().ServeHTTP(rec, req)
		if rec.Code != http.StatusOK {
			t.Fatalf("status = %d; body=%s", rec.Code, rec.Body.String())
		}
	}
	post()
	post() // same date + amount → must not overwrite the first file

	entries, err := os.ReadDir(filepath.Join(s.cfg.StorageDir, "2026"))
	if err != nil {
		t.Fatal(err)
	}
	got := map[string]bool{}
	for _, e := range entries {
		got[e.Name()] = true
	}
	if !got["06_01_12.34.png"] || !got["06_01_12.34_1.png"] {
		t.Errorf("expected both base and _1 files, got %v", got)
	}
}

func TestUpload_BadAmount_RerendersWithErrorNoRow(t *testing.T) {
	s := testServerWithStore(t)
	body, ct := multipartUpload(t,
		map[string]string{"amount": "abc", "receipt_date": "2026-06-01", "category_id": aCategoryID(t, s)},
		"receipt", "receipt.png", fakePNG())

	req := httptest.NewRequest(http.MethodPost, "/upload", body)
	req.Header.Set("Content-Type", ct)
	req.AddCookie(authCookie(t, s))
	rec := httptest.NewRecorder()
	s.Routes().ServeHTTP(rec, req)

	if rec.Code != http.StatusOK {
		t.Fatalf("status = %d, want 200 (re-render)", rec.Code)
	}
	if !strings.Contains(rec.Body.String(), "valid amount") {
		t.Errorf("missing amount error: %s", rec.Body.String())
	}
	n, _ := s.store.CountActive()
	if n != 0 {
		t.Errorf("CountActive = %d, want 0 (nothing stored on validation error)", n)
	}
}

func TestUpload_RejectsNonImageNonPDF(t *testing.T) {
	s := testServerWithStore(t)
	body, ct := multipartUpload(t,
		map[string]string{"amount": "5.00", "receipt_date": "2026-06-01", "category_id": aCategoryID(t, s)},
		"receipt", "notes.txt", []byte("just plain text, not an image or pdf"))

	req := httptest.NewRequest(http.MethodPost, "/upload", body)
	req.Header.Set("Content-Type", ct)
	req.AddCookie(authCookie(t, s))
	rec := httptest.NewRecorder()
	s.Routes().ServeHTTP(rec, req)

	if !strings.Contains(rec.Body.String(), "images and PDFs") {
		t.Errorf("expected mime rejection: %s", rec.Body.String())
	}
	n, _ := s.store.CountActive()
	if n != 0 {
		t.Errorf("CountActive = %d, want 0", n)
	}
}

func TestExportDB_StreamsSQLiteFile(t *testing.T) {
	s := testServerWithStore(t)
	// Seed one receipt via the upload handler.
	body, ct := multipartUpload(t,
		map[string]string{"amount": "9.99", "receipt_date": "2026-06-01", "category_id": aCategoryID(t, s)},
		"receipt", "r.png", fakePNG())
	req := httptest.NewRequest(http.MethodPost, "/upload", body)
	req.Header.Set("Content-Type", ct)
	req.AddCookie(authCookie(t, s))
	s.Routes().ServeHTTP(httptest.NewRecorder(), req)

	for _, blobs := range []string{"true", "false"} {
		req := httptest.NewRequest(http.MethodGet, "/export/db?blobs="+blobs, nil)
		req.AddCookie(authCookie(t, s))
		rec := httptest.NewRecorder()
		s.Routes().ServeHTTP(rec, req)

		if rec.Code != http.StatusOK {
			t.Fatalf("blobs=%s: status = %d, want 200", blobs, rec.Code)
		}
		if ct := rec.Header().Get("Content-Type"); ct != "application/octet-stream" {
			t.Errorf("blobs=%s: content-type = %q", blobs, ct)
		}
		if !strings.HasPrefix(rec.Body.String(), "SQLite format 3") {
			t.Errorf("blobs=%s: body is not a SQLite file", blobs)
		}
	}
}