package web

import (
	"fmt"
	"net/http"
	"net/http/httptest"
	"os"
	"path/filepath"
	"strings"
	"testing"
	"time"

	"git.petrovv.com/nikola/money/internal/config"
	"git.petrovv.com/nikola/money/internal/parser"
	"git.petrovv.com/nikola/money/internal/rules"
	"git.petrovv.com/nikola/money/internal/store"
	"git.petrovv.com/nikola/money/internal/transfers"
)

// The upload tests are about where files land and what is refused, not about
// any bank's layout, so they read "date,description,amount" with a header.
func init() {
	parser.Register("webtest", func(acc *config.Account) (parser.Parser, error) {
		return csvParser{digits: acc.Digits()}, nil
	})
}

type csvParser struct{ digits int }

func (p csvParser) Parse(path string, _ *config.Account) ([]parser.RawTxn, error) {
	body, err := os.ReadFile(path)
	if err != nil {
		return nil, err
	}
	var txns []parser.RawTxn
	for i, line := range strings.Split(strings.TrimSpace(string(body)), "\n")[1:] {
		f := strings.Split(line, ",")
		if len(f) != 3 {
			return nil, fmt.Errorf("row %d: want 3 fields", i+2)
		}
		amount, err := parser.ParseAmount(f[2], ".", "", p.digits)
		if err != nil {
			return nil, err
		}
		txns = append(txns, parser.RawTxn{Date: f[0], Description: f[1], AmountMinor: amount})
	}
	return txns, nil
}

// newUploadServer builds a server over a data root with one empty account
// folder, as `money serve` sees it before the first import.
func newUploadServer(t *testing.T, accountTOML string) (string, http.Handler) {
	t.Helper()
	root := t.TempDir()
	dir := filepath.Join(root, "checking")
	if err := os.MkdirAll(dir, 0o755); err != nil {
		t.Fatal(err)
	}
	if err := os.WriteFile(filepath.Join(dir, config.AccountFile), []byte(accountTOML), 0o644); err != nil {
		t.Fatal(err)
	}
	db, err := store.Open(config.IndexPath(root))
	if err != nil {
		t.Fatal(err)
	}
	t.Cleanup(func() { db.Close() })
	accounts, err := config.LoadAccounts(root)
	if err != nil {
		t.Fatal(err)
	}
	loaded, err := config.LoadRules(root)
	if err != nil {
		t.Fatal(err)
	}
	s := New(root, db, accounts, rules.New(loaded), transfers.New(loaded))
	s.now = func() time.Time { return time.Date(2026, 3, 15, 0, 0, 0, 0, time.UTC) }
	return dir, s.Handler()
}

const checkingTOML = "currency = \"EUR\"\nparser = \"webtest\"\n"

const statement = "date,description,amount\n2026-02-01,LIDL SOFIA,-12.50\n2026-02-03,SALARY,1000.00\n"

func TestUploadSavesAndImports(t *testing.T) {
	dir, h := newUploadServer(t, checkingTOML)
	req := uploadReq{Account: "checking", Files: []uploadFile{{Name: "2026-02.csv", Data: []byte(statement)}}}

	var res importJSON
	call(t, h, "POST", "/api/upload", req, http.StatusOK, &res)
	if !strings.Contains(res.Status, "uploaded 1 file(s) to checking") || !strings.Contains(res.Status, "2 new") {
		t.Errorf("status = %q", res.Status)
	}
	if got, err := os.ReadFile(filepath.Join(dir, "2026-02.csv")); err != nil || string(got) != statement {
		t.Errorf("file on disk = %q, %v", got, err)
	}
	var txns struct{ Rows []txnRow }
	call(t, h, "GET", "/api/transactions", nil, http.StatusOK, &txns)
	if len(txns.Rows) != 2 {
		t.Errorf("index holds %d rows, want the 2 uploaded", len(txns.Rows))
	}

	// The same file again is not an error, and adds nothing.
	call(t, h, "POST", "/api/upload", req, http.StatusOK, &res)
	if !strings.Contains(res.Status, "uploaded 0 file(s)") || !strings.Contains(res.Status, "1 already there") {
		t.Errorf("re-upload status = %q", res.Status)
	}
	call(t, h, "GET", "/api/transactions", nil, http.StatusOK, &txns)
	if len(txns.Rows) != 2 {
		t.Errorf("re-upload left %d rows, want 2", len(txns.Rows))
	}
}

// A statement already in the folder is the source of truth for what it
// imported, so an upload never replaces one with different contents.
func TestUploadNeverReplacesAStatement(t *testing.T) {
	dir, h := newUploadServer(t, checkingTOML)
	path := filepath.Join(dir, "2026-02.csv")
	if err := os.WriteFile(path, []byte(statement), 0o644); err != nil {
		t.Fatal(err)
	}
	req := uploadReq{Account: "checking", Files: []uploadFile{{Name: "2026-02.csv", Data: []byte("date,description,amount\n")}}}
	call(t, h, "POST", "/api/upload", req, http.StatusConflict, nil)
	if got, _ := os.ReadFile(path); string(got) != statement {
		t.Errorf("statement was overwritten: %q", got)
	}
}

// A batch is checked as a whole before anything is written, and nothing may
// land outside the account folder or where import would not read it back.
func TestUploadRefusesBadNames(t *testing.T) {
	dir, h := newUploadServer(t, checkingTOML+"include = [\"*.csv\"]\n")
	for _, bad := range []string{"../escape.csv", "sub/x.csv", ".hidden.csv", config.AccountFile, "notes.txt", ""} {
		req := uploadReq{Account: "checking", Files: []uploadFile{
			{Name: "good.csv", Data: []byte(statement)},
			{Name: bad, Data: []byte(statement)},
		}}
		call(t, h, "POST", "/api/upload", req, http.StatusBadRequest, nil)
	}
	entries, _ := os.ReadDir(dir)
	if len(entries) != 1 {
		var names []string
		for _, e := range entries {
			names = append(names, e.Name())
		}
		t.Errorf("folder holds %v, want only %s", names, config.AccountFile)
	}
	if _, err := os.Stat(filepath.Join(filepath.Dir(dir), "escape.csv")); err == nil {
		t.Error("a file escaped the account folder")
	}

	call(t, h, "POST", "/api/upload", uploadReq{Account: "nope", Files: []uploadFile{{Name: "a.csv"}}},
		http.StatusBadRequest, nil)
}

// Multipart is what a cross-site form can send, so it is refused like any
// other non-JSON write.
func TestUploadRefusesMultipart(t *testing.T) {
	_, h := newUploadServer(t, checkingTOML)
	r := httptest.NewRequest("POST", "/api/upload", strings.NewReader("--x\r\n"))
	r.Header.Set("Content-Type", "multipart/form-data; boundary=x")
	w := httptest.NewRecorder()
	h.ServeHTTP(w, r)
	if w.Code != http.StatusUnsupportedMediaType {
		t.Errorf("status %d, want %d", w.Code, http.StatusUnsupportedMediaType)
	}
}