package main

import (
	"bytes"
	"flag"
	"fmt"
	"net/http"
	"os"
	"path/filepath"
	"runtime"
	"strings"
	"sync"
	"time"

	"github.com/OpenPrinting/goipp"

	"github.com/VeraeLLC/PrintToVeraeTimeStamp/internal/auth"
	"github.com/VeraeLLC/PrintToVeraeTimeStamp/internal/job"
	"github.com/VeraeLLC/PrintToVeraeTimeStamp/internal/veraeapi"
	"github.com/VeraeLLC/PrintToVeraeTimeStamp/internal/vlog"
	"github.com/VeraeLLC/PrintToVeraeTimeStamp/internal/winprint"
)

func isHelperExe() bool {
	exe, err := os.Executable()
	if err != nil {
		return false
	}
	return strings.Contains(strings.ToLower(filepath.Base(exe)), "printhelper")
}

// fallbackDropDir is the folder the "Verae TimeStamp PDF (Local Port)" queue writes into.
func fallbackDropDir() string {
	if v := os.Getenv("VERAE_FALLBACK_DIR"); v != "" {
		return v
	}
	if runtime.GOOS == "windows" {
		pd := os.Getenv("ProgramData")
		if pd == "" {
			pd = `C:\ProgramData`
		}
		return filepath.Join(pd, "Verae", "spool", "fallback")
	}
	return filepath.Join(os.TempDir(), "verae-fallback")
}

func userWorkDir() string {
	base, err := os.UserCacheDir() // %LOCALAPPDATA% on Windows
	if err != nil {
		base = os.TempDir()
	}
	return filepath.Join(base, "Verae", "PrintStamp", "spool")
}

func runServe(args []string) int {
	fs := flag.NewFlagSet("serve", flag.ExitOnError)
	addr := fs.String("addr", envOr("VERAE_IPP_ADDR", "127.0.0.1:8631"), "IPP listen address")
	noIPP := fs.Bool("no-ipp", false, "disable IPP loopback printer")
	noWatch := fs.Bool("no-watch", false, "disable fallback folder watcher")
	debug := fs.Bool("debug", false, "verbose logging (also VERAE_DEBUG=1)")
	outDir := fs.String("out-dir", "", "output dir (default Documents\\Verae Timestamps)")
	_ = fs.Parse(args)

	vlog.SetDebug(*debug || debugFromRegistry())
	logPath := vlog.Init("helper", !isHelperExe())
	host, _ := os.Hostname()
	home, _ := os.UserHomeDir()
	exe, _ := os.Executable()
	vlog.Printf("==== verae-print helper %s start exe=%q os=%s/%s host=%s home=%q log=%q debug=%v",
		job.HelperVersion, exe, runtime.GOOS, runtime.GOARCH, host, home, logPath, vlog.DebugEnabled())
	logAuthState()

	proc := makeProcessor(*outDir)
	errc := make(chan error, 2)
	if !*noIPP {
		srv := &winprint.IPPServer{Addr: *addr, Name: "Verae TimeStamp PDF", SpoolDir: filepath.Join(userWorkDir(), "ipp"), Process: proc}
		go func() { errc <- srv.ListenAndServe() }()
	}
	if !*noWatch {
		w := &winprint.Watcher{Dir: fallbackDropDir(), WorkDir: filepath.Join(userWorkDir(), "fallback"), Process: proc}
		go w.Run()
	}
	if *noIPP {
		select {}
	}
	err := <-errc
	vlog.Errorf("helper exiting: %v", err)
	fmt.Fprintln(os.Stderr, err)
	return 1
}

func logAuthState() {
	_, xerr := auth.LoadXVeraeToken()
	_, jerr := auth.LoadVeraeJWT()
	vlog.Printf("auth: preferred=%s xVerae-token=%v jwt(auth.properties)=%v", auth.PreferredChannel(), errState(xerr), errState(jerr))
}

func errState(err error) string {
	if err == nil {
		return "present"
	}
	return "missing (" + err.Error() + ")"
}

var setupOnce sync.Once

func makeProcessor(outDir string) winprint.Processor {
	return func(j winprint.Job) error {
		lj := vlog.Job(j.ID)
		lj.Printf("process: source=%s title=%q user=%q format=%s bytes=%d path=%q", j.Source, j.Title, j.User, j.Format, j.Bytes, j.Path)
		if !strings.Contains(j.Format, "pdf") && sniffPDF(j.Path) == false {
			return fmt.Errorf("received %s (not PDF); raster→PDF conversion not implemented in this debug build — file kept at %s. Re-test with VERAE_IPP_FORMATS=application/pdf", j.Format, j.Path)
		}
		ch := auth.PreferredChannel()
		client := &veraeapi.Client{Channel: ch}
		switch ch {
		case auth.ChannelZapier:
			tok, err := auth.LoadXVeraeToken()
			if err != nil {
				if jwt, jerr := auth.LoadVeraeJWT(); jerr == nil {
					lj.Printf("process: no xVerae- token, falling back to verae channel (auth.properties)")
					ch, client.Channel, client.VeraeToken = auth.ChannelVerae, auth.ChannelVerae, jwt
					break
				}
				setupOnce.Do(launchSetupUI)
				return fmt.Errorf("no signing key: %v — run 'verae-print setup' then reprint (PDF kept at %s)", err, j.Path)
			}
			client.XVeraeToken = tok
		default:
			tok, err := auth.LoadVeraeJWT()
			if err != nil {
				return fmt.Errorf("verae channel: %v", err)
			}
			client.VeraeToken = tok
		}
		client.HTTPDo = loggingDo(lj)
		name := safeStem(j.Title)
		start := time.Now()
		res, err := job.Run(job.Options{SourcePDF: j.Path, OutDir: outDir, DocumentName: name + ".pdf", Channel: ch, Client: client})
		if err != nil {
			notifyUser("Verae timestamp FAILED", err.Error())
			return err
		}
		lj.Printf("process: OK in %s receipt=%s sha256=%s\n  original=%q\n  cert=%q\n  json=%q",
			time.Since(start).Round(time.Millisecond), res.ReceiptID, res.SHA256, res.OriginalPDF, res.CertificatePDF, res.ReceiptJSON)
		_ = os.Remove(j.Path)
		notifyUser(fmt.Sprintf("Verae timestamp %s", res.ReceiptID), res.CertificatePDF)
		return nil
	}
}

func loggingDo(lj vlog.Job) func(*http.Request) (*http.Response, error) {
	return func(r *http.Request) (*http.Response, error) {
		start := time.Now()
		res, err := http.DefaultClient.Do(r)
		if err != nil {
			lj.Errorf("api: %s %s → error after %s: %v", r.Method, r.URL.Redacted(), time.Since(start).Round(time.Millisecond), err)
			return res, err
		}
		lj.Printf("api: %s %s → HTTP %d in %s", r.Method, r.URL.Redacted(), res.StatusCode, time.Since(start).Round(time.Millisecond))
		return res, nil
	}
}

func sniffPDF(p string) bool {
	f, err := os.Open(p)
	if err != nil {
		return false
	}
	defer f.Close()
	b := make([]byte, 5)
	n, _ := f.Read(b)
	return n == 5 && string(b) == "%PDF-"
}

func safeStem(title string) string {
	t := filepath.Base(strings.ReplaceAll(title, `\`, "/"))
	if ext := filepath.Ext(t); ext != "" && len(ext) <= 5 {
		t = strings.TrimSuffix(t, ext)
	}
	var b strings.Builder
	for _, r := range t {
		switch {
		case r == ' ' || r == '-' || r == '_' || r == '.' || (r >= '0' && r <= '9') || (r >= 'a' && r <= 'z') || (r >= 'A' && r <= 'Z'):
			b.WriteRune(r)
		}
		if b.Len() >= 80 {
			break
		}
	}
	s := strings.TrimSpace(b.String())
	if s == "" {
		s = "document-" + time.Now().Format("20060102-150405")
	}
	return s
}

// runIPPSelftest sends Get-Printer-Attributes + Validate-Job to the helper.
func runIPPSelftest(args []string) int {
	fs := flag.NewFlagSet("ipp-selftest", flag.ExitOnError)
	addr := fs.String("addr", "127.0.0.1:8631", "helper address")
	_ = fs.Parse(args)
	uri := "ipp://" + *addr + "/ipp/print"
	ok := true
	for _, op := range []goipp.Op{goipp.OpGetPrinterAttributes, goipp.OpValidateJob} {
		m := goipp.NewRequest(goipp.DefaultVersion, op, 1)
		m.Operation.Add(goipp.MakeAttribute("attributes-charset", goipp.TagCharset, goipp.String("utf-8")))
		m.Operation.Add(goipp.MakeAttribute("attributes-natural-language", goipp.TagLanguage, goipp.String("en")))
		m.Operation.Add(goipp.MakeAttribute("printer-uri", goipp.TagURI, goipp.String(uri)))
		if op == goipp.OpValidateJob {
			m.Operation.Add(goipp.MakeAttribute("document-format", goipp.TagMimeType, goipp.String("application/pdf")))
		}
		b, _ := m.EncodeBytes()
		res, err := http.Post("http://"+*addr+"/ipp/print", goipp.ContentType, bytes.NewReader(b))
		if err != nil {
			fmt.Printf("FAIL %s: %v\n", op, err)
			return 1
		}
		var out goipp.Message
		err = out.Decode(res.Body)
		res.Body.Close()
		if err != nil {
			fmt.Printf("FAIL %s: decode: %v\n", op, err)
			return 1
		}
		st := goipp.Status(out.Code)
		fmt.Printf("%s → %s (%d printer attrs)\n", op, st, len(out.Printer))
		if st != goipp.StatusOk {
			ok = false
		}
		if op == goipp.OpGetPrinterAttributes {
			for _, a := range out.Printer {
				if a.Name == "document-format-supported" || a.Name == "printer-name" || a.Name == "printer-uri-supported" {
					fmt.Printf("  %s = %s\n", a.Name, a.Values)
				}
			}
		}
	}
	if !ok {
		return 1
	}
	fmt.Println("IPP helper OK:", uri)
	return 0
}