package sshmanager

import (
	"bytes"
	"context"
	"fmt"
	"log/slog"
	"net"
	"os"
	"path/filepath"
	"time"

	"golang.org/x/crypto/ssh"
)

type DeployKey struct {
	LocalPath  string
	RemotePath string
	Mode       uint32
}

type DeployResult struct {
	Success  bool
	Messages []string
	Errors   []string
}

func DeployKeysToMachine(ctx context.Context, serverKeyPath string, host string, port int, user string, keys []DeployKey, knownHostsHosts []string) (*DeployResult, error) {
	result := &DeployResult{Success: true, Messages: []string{}, Errors: []string{}}

	addr := fmt.Sprintf("%s:%d", host, port)

	keyData, err := os.ReadFile(serverKeyPath)
	if err != nil {
		return nil, fmt.Errorf("reading server key: %w", err)
	}
	signer, err := ssh.ParsePrivateKey(keyData)
	if err != nil {
		return nil, fmt.Errorf("parsing server key: %w", err)
	}

	hostKeyCallback := func(hostname string, remote net.Addr, key ssh.PublicKey) error {
		return nil
	}

	cfg := &ssh.ClientConfig{
		User:            user,
		Auth:            []ssh.AuthMethod{ssh.PublicKeys(signer)},
		HostKeyCallback: hostKeyCallback,
		Timeout:         10 * time.Second,
	}

	ctx, cancel := context.WithTimeout(ctx, 60*time.Second)
	defer cancel()

	conn, err := ssh.Dial("tcp", addr, cfg)
	if err != nil {
		slog.Warn("deploy keys: SSH dial failed", "host", addr, "error", err)
		return &DeployResult{Success: false, Messages: []string{}, Errors: []string{fmt.Sprintf("connecting to %s: %v", addr, err)}}, nil
	}
	defer conn.Close()

	remoteSSHDir := "/var/lib/syncserver/ssh"
	remoteKeysDir := filepath.Join(remoteSSHDir, "keys")

	session, err := conn.NewSession()
	if err != nil {
		return nil, fmt.Errorf("creating session: %w", err)
	}
	defer session.Close()

	var stdout, stderr bytes.Buffer
	session.Stdout = &stdout
	session.Stderr = &stderr

	if err := session.Run(fmt.Sprintf("mkdir -p %s && chmod 700 %s", remoteKeysDir, remoteKeysDir)); err != nil {
		return nil, fmt.Errorf("creating remote ssh dir: %s %w", stderr.String(), err)
	}
	result.Messages = append(result.Messages, fmt.Sprintf("Created %s on %s", remoteKeysDir, host))

	for _, k := range keys {
		keyContent, err := os.ReadFile(k.LocalPath)
		if err != nil {
			result.Errors = append(result.Errors, fmt.Sprintf("reading local key %s: %v", k.LocalPath, err))
			result.Success = false
			continue
		}

		mode := k.Mode
		if mode == 0 {
			mode = 0600
		}

		sess2, err := conn.NewSession()
		if err != nil {
			result.Errors = append(result.Errors, fmt.Sprintf("session for key upload: %v", err))
			result.Success = false
			continue
		}
		defer sess2.Close()

		sess2.Stdout = &stdout
		sess2.Stderr = &stderr

		slog.Debug("deploy: uploading key", "local", k.LocalPath, "remote", k.RemotePath, "host", host)

		cmd := fmt.Sprintf("cat > %s && chmod 0%o %s", k.RemotePath, mode, k.RemotePath)

		stdin, err := sess2.StdinPipe()
		if err != nil {
			result.Errors = append(result.Errors, fmt.Sprintf("stdin pipe for %s: %v", k.RemotePath, err))
			result.Success = false
			sess2.Close()
			continue
		}

		if err := sess2.Start(cmd); err != nil {
			result.Errors = append(result.Errors, fmt.Sprintf("starting command for %s: %v", k.RemotePath, err))
			result.Success = false
			sess2.Close()
			continue
		}

		_, err = stdin.Write(keyContent)
		if err != nil {
			result.Errors = append(result.Errors, fmt.Sprintf("writing key %s: %v", k.RemotePath, err))
			result.Success = false
			stdin.Close()
			sess2.Close()
			continue
		}
		stdin.Close()

		if err := sess2.Wait(); err != nil {
			result.Errors = append(result.Errors, fmt.Sprintf("uploading %s: %v (stderr: %s)", k.RemotePath, err, stderr.String()))
			result.Success = false
			continue
		}

		result.Messages = append(result.Messages, fmt.Sprintf("Uploaded %s to %s:%s", filepath.Base(k.LocalPath), host, k.RemotePath))
	}

		if len(knownHostsHosts) > 0 {
		for _, khHost := range knownHostsHosts {
			session2, err := conn.NewSession()
			if err != nil {
				result.Errors = append(result.Errors, fmt.Sprintf("session for ssh-keyscan %s: %v", khHost, err))
				continue
			}
			session2.Stdout = &stdout
			session2.Stderr = &stderr
			err = session2.Run(fmt.Sprintf("ssh-keyscan -H -p %s 2>/dev/null >> %s/known_hosts", khHost, remoteSSHDir))
			session2.Close()
			if err != nil {
				slog.Warn("deploy: ssh-keyscan failed", "host", khHost, "error", err)
				result.Errors = append(result.Errors, fmt.Sprintf("ssh-keyscan %s: %v (stderr: %s)", khHost, err, stderr.String()))
			} else {
				result.Messages = append(result.Messages, fmt.Sprintf("Populated known_hosts with %s", khHost))
			}
		}
	}

	slog.Info("deploy keys result", "host", host, "success", result.Success, "messages", len(result.Messages), "errors", len(result.Errors))
	return result, nil
}