// Package integration exercises an explicitly supplied official Gitea binary.
// Everything runs on loopback with disposable users, SQLite and captured SMTP.
package integration

import (
	"bufio"
	"bytes"
	"context"
	"encoding/base64"
	"fmt"
	"io"
	"mime"
	"mime/multipart"
	"mime/quotedprintable"
	"net"
	"net/http"
	"net/http/cookiejar"
	"net/mail"
	"net/textproto"
	"net/url"
	"os"
	"os/exec"
	"path/filepath"
	"strings"
	"sync"
	"testing"
	"time"

	"gitea-mail-templates/tools/builder"
	"gitea-mail-templates/tools/upstream"
)

type safeLog struct {
	mu  sync.Mutex
	buf bytes.Buffer
}

func (l *safeLog) Write(p []byte) (int, error) {
	l.mu.Lock()
	defer l.mu.Unlock()
	return l.buf.Write(p)
}
func (l *safeLog) String() string { l.mu.Lock(); defer l.mu.Unlock(); return l.buf.String() }

func smtpCapture(t *testing.T) (int, <-chan []byte) {
	t.Helper()
	listener, err := net.Listen("tcp", "127.0.0.1:0")
	if err != nil {
		t.Fatal(err)
	}
	t.Cleanup(func() { listener.Close() })
	mailbox := make(chan []byte, 4)
	go func() {
		for {
			conn, err := listener.Accept()
			if err != nil {
				return
			}
			go func() {
				defer conn.Close()
				conn.SetDeadline(time.Now().Add(time.Minute))
				r := textproto.NewReader(bufio.NewReader(conn))
				fmt.Fprint(conn, "220 localhost SMTP capture\r\n")
				for {
					line, err := r.ReadLine()
					if err != nil {
						return
					}
					fields := strings.Fields(line)
					if len(fields) == 0 {
						continue
					}
					command := strings.ToUpper(fields[0])
					switch command {
					case "EHLO", "HELO":
						fmt.Fprint(conn, "250 localhost\r\n")
					case "DATA":
						fmt.Fprint(conn, "354 Send mail\r\n")
						data, err := r.ReadDotBytes()
						if err != nil {
							return
						}
						mailbox <- data
						fmt.Fprint(conn, "250 Captured\r\n")
					case "QUIT":
						fmt.Fprint(conn, "221 Goodbye\r\n")
						return
					default:
						fmt.Fprint(conn, "250 OK\r\n")
					}
				}
			}()
		}
	}()
	return listener.Addr().(*net.TCPAddr).Port, mailbox
}

func TestGiteaMailSmoke(t *testing.T) {
	binary := os.Getenv("GITEA_SMOKE_BINARY")
	if binary == "" {
		t.Skip("set GITEA_SMOKE_BINARY to a checksum-verified official Gitea binary")
	}
	binary, err := filepath.Abs(binary)
	if err != nil {
		t.Fatal(err)
	}
	s, err := upstream.Load(filepath.Join("..", "..", "build", "upstream"))
	if err != nil {
		t.Fatal(err)
	}
	version, err := exec.Command(binary, "--version").CombinedOutput()
	if err != nil {
		t.Fatal(err)
	}
	fields := strings.Fields(strings.ToLower(string(version)))
	if len(fields) < 3 || fields[0] != "gitea" || fields[1] != "version" || fields[2] != strings.TrimPrefix(s.Lock.Tag, "v") {
		t.Fatalf("binary does not match snapshot: %s", version)
	}
	for _, mode := range []string{"shared", "framed"} {
		t.Run(mode, func(t *testing.T) { smokeMode(t, binary, s, mode) })
	}
}

func smokeMode(t *testing.T, binary string, s *upstream.Snapshot, mode string) {
	port, mailbox := smtpCapture(t)
	probe, err := net.Listen("tcp", "127.0.0.1:0")
	if err != nil {
		t.Fatal(err)
	}
	webPort := probe.Addr().(*net.TCPAddr).Port
	probe.Close()
	work := t.TempDir()
	// Preseed only Gitea's disposable Git home; never touch the user's Git config.
	gitHome := filepath.Join(work, "data", "home")
	if err := os.MkdirAll(gitHome, 0755); err != nil {
		t.Fatal(err)
	}
	gitConfig := "[user]\nname = Gitea\nemail = gitea@fake.local\n[core]\nquotepath = false\nlongpaths = true\ncommitGraph = true\n[gc]\nwriteCommitGraph = true\n[fetch]\nwriteCommitGraph = true\n[init]\ndefaultBranch = main\n[receive]\nadvertisePushOptions = true\nprocReceiveRefs = refs/for\n[uploadpack]\nallowfilter = true\nallowAnySHA1InWant = true\n[safe]\ndirectory = *\n"
	if err := os.WriteFile(filepath.Join(gitHome, ".gitconfig"), []byte(gitConfig), 0600); err != nil {
		t.Fatal(err)
	}
	custom := filepath.Join(work, "custom")
	configFile := filepath.Join(work, "app.ini")
	rootURL := fmt.Sprintf("http://127.0.0.1:%d/", webPort)
	ini := fmt.Sprintf("APP_NAME = Smoke Gitea\nRUN_MODE = prod\n[server]\nAPP_DATA_PATH = %s/data\nHTTP_ADDR = 127.0.0.1\nHTTP_PORT = %d\nROOT_URL = %s\nDISABLE_SSH = true\n[database]\nDB_TYPE = sqlite3\nPATH = %s/gitea.db\n[repository]\nROOT = %s/repos\n[security]\nINSTALL_LOCK = true\n[service]\nDISABLE_REGISTRATION = true\nREGISTER_EMAIL_CONFIRM = false\nENABLE_NOTIFY_MAIL = true\n[mailer]\nENABLED = true\nPROTOCOL = smtp\nSMTP_ADDR = 127.0.0.1\nSMTP_PORT = %d\nFROM = Smoke Gitea <smoke@example.invalid>\n[log]\nMODE = console\nLEVEL = warn\n", filepath.ToSlash(work), webPort, rootURL, filepath.ToSlash(work), filepath.ToSlash(work), port)
	if err := os.WriteFile(configFile, []byte(ini), 0600); err != nil {
		t.Fatal(err)
	}
	// Disable key-file maintenance and isolate even its unused paths from HOME.
	ini = strings.Replace(ini, "DISABLE_SSH = true", "DISABLE_SSH = true\nSSH_ROOT_PATH = "+filepath.ToSlash(filepath.Join(work, "ssh"))+"\nSSH_CREATE_AUTHORIZED_KEYS_FILE = false\nSSH_CREATE_AUTHORIZED_PRINCIPALS_FILE = false", 1)
	if err := os.WriteFile(configFile, []byte(ini), 0600); err != nil {
		t.Fatal(err)
	}
	var p *builder.Package
	if mode == "framed" {
		theme, err := builder.LoadTheme(filepath.Join("..", "..", "themes", "horizon"))
		if err != nil {
			t.Fatal(err)
		}
		p, err = builder.Build(s, theme)
		if err != nil {
			t.Fatal(err)
		}
	} else {
		p, err = builder.Build(s, &builder.Theme{Name: "smoke", Mode: "shared", CSS: "a { color: #123456; }"})
		if err != nil {
			t.Fatal(err)
		}
	}
	for name, data := range p.Files {
		target := filepath.Join(custom, "templates", filepath.FromSlash(name))
		if err := os.MkdirAll(filepath.Dir(target), 0755); err != nil {
			t.Fatal(err)
		}
		if err := os.WriteFile(target, data, 0644); err != nil {
			t.Fatal(err)
		}
	}
	args := []string{"--work-path", work, "--custom-path", custom, "--config", configFile}
	run := func(more ...string) {
		ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
		defer cancel()
		cmd := exec.CommandContext(ctx, binary, append(append([]string{}, args...), more...)...)
		output, err := cmd.CombinedOutput()
		if err != nil {
			t.Fatalf("Gitea %v: %v\n%s", more, err, output)
		}
	}
	run("migrate")
	run("admin", "user", "create", "--username", "smoke-user", "--password", "local-smoke-password-123!", "--email", "smoke@example.invalid", "--admin", "--must-change-password=false")
	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()
	var logs safeLog
	web := exec.CommandContext(ctx, binary, append(args, "web")...)
	web.Stdout = &logs
	web.Stderr = &logs
	if err := web.Start(); err != nil {
		t.Fatal(err)
	}
	done := make(chan struct{})
	go func() { _ = web.Wait(); close(done) }()
	t.Cleanup(func() { cancel(); <-done })
	jar, _ := cookiejar.New(nil)
	client := &http.Client{Jar: jar, Timeout: 5 * time.Second}
	deadline := time.Now().Add(30 * time.Second)
	var page []byte
	for time.Now().Before(deadline) {
		select {
		case <-done:
			t.Fatalf("Gitea exited: %s", logs.String())
		default:
		}
		resp, err := client.Get(rootURL + "user/forgot_password")
		if err == nil {
			page, _ = io.ReadAll(resp.Body)
			resp.Body.Close()
			if resp.StatusCode == 200 {
				break
			}
		}
		time.Sleep(100 * time.Millisecond)
	}
	if len(page) == 0 {
		t.Fatalf("Gitea did not start: %s", logs.String())
	}
	if !bytes.Contains(page, []byte(`name="email"`)) {
		t.Fatalf("no reset form: %s\n%s", page, logs.String())
	}
	// Gitea 28 uses origin checks rather than a hidden _csrf form field.
	req, err := http.NewRequest(http.MethodPost, rootURL+"user/forgot_password", strings.NewReader(url.Values{"email": {"smoke@example.invalid"}}.Encode()))
	if err != nil {
		t.Fatal(err)
	}
	req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
	req.Header.Set("Origin", strings.TrimSuffix(rootURL, "/"))
	resp, err := client.Do(req)
	if err != nil {
		t.Fatal(err)
	}
	io.Copy(io.Discard, resp.Body)
	resp.Body.Close()
	if resp.StatusCode != 200 {
		t.Fatalf("password reset HTTP %d: %s", resp.StatusCode, logs.String())
	}
	select {
	case raw := <-mailbox:
		message, err := mail.ReadMessage(bytes.NewReader(raw))
		if err != nil {
			t.Fatal(err)
		}
		parts, err := mimeBodies(message.Header.Get("Content-Type"), message.Header.Get("Content-Transfer-Encoding"), message.Body)
		if err != nil {
			t.Fatal(err)
		}
		body := parts["text/html"]
		if !strings.Contains(body, "/user/recover_account?code=") || !strings.Contains(body, "<style>") {
			t.Fatalf("official reset body or injected head missing: %s", body)
		}
		if mode == "framed" && !strings.Contains(body, `class="email-wrap`) {
			t.Fatal("framed override was not loaded")
		}
		if mode == "framed" && (!strings.Contains(body, `class="email-btn">Recover your account</a>`) || !strings.Contains(body, `src="`+rootURL+`assets/img/favicon.png"`) || strings.Count(body, "/user/recover_account?code=") < 3) {
			t.Fatal("shared action label, fallback or instance logo missing from real mail")
		}
		if mode == "shared" && (!strings.Contains(body, "#123456") || strings.Contains(body, `class="email-wrap`)) {
			t.Fatal("shared partial was not loaded")
		}
		if !strings.Contains(parts["text/plain"], "recover_account") {
			t.Fatal("Gitea plain-text alternative missing official recovery link")
		}
		t.Logf("[PASS] %s %s: real password-reset mail captured; HTML override and plain-text link verified", s.Lock.Tag, mode)
	case <-time.After(20 * time.Second):
		t.Fatalf("no mail captured: %s", logs.String())
	}
}

func mimeBodies(contentType, encoding string, r io.Reader) (map[string]string, error) {
	media, params, err := mime.ParseMediaType(contentType)
	if err != nil {
		return nil, err
	}
	result := map[string]string{}
	if strings.HasPrefix(media, "multipart/") {
		reader := multipart.NewReader(r, params["boundary"])
		for {
			part, err := reader.NextPart()
			if err == io.EOF {
				break
			}
			if err != nil {
				return nil, err
			}
			bodies, err := mimeBodies(part.Header.Get("Content-Type"), part.Header.Get("Content-Transfer-Encoding"), part)
			if err != nil {
				return nil, err
			}
			for k, v := range bodies {
				result[k] = v
			}
		}
		return result, nil
	}
	switch strings.ToLower(encoding) {
	case "quoted-printable":
		r = quotedprintable.NewReader(r)
	case "base64":
		r = base64.NewDecoder(base64.StdEncoding, r)
	}
	b, err := io.ReadAll(r)
	if err != nil {
		return nil, err
	}
	result[media] = string(b)
	return result, nil
}