package main

import (
	"bytes"
	"errors"
	"fmt"
	"os"
	"os/exec"
	"path/filepath"
	"strings"

	"github.com/pelletier/go-toml/v2"
)

const (
	defaultServiceDirTemplate = "/root/pb/{service}"
	defaultEnvFileTemplate    = "/root/pb/{service}/.env"
	totalDeploySteps          = 7
)

type pbToml struct {
	Server     serverConfig     `toml:"server"`
	PocketBase pocketBaseConfig `toml:"pocketbase"`
}

type serverConfig struct {
	IP     string `toml:"ip"`
	Port   int    `toml:"port"`
	Domain string `toml:"domain"`
}

type pocketBaseConfig struct {
	Version     string `toml:"version"`
	ServiceName string `toml:"service_name"`
}

func runDeploy() error {
	cwd, err := os.Getwd()
	if err != nil {
		return err
	}

	configPath := filepath.Join(cwd, "pb.toml")
	cfg, err := loadPBConfig(configPath)
	if err != nil {
		return err
	}

	serviceName := cfg.PocketBase.ServiceName
	if serviceName == "" {
		return fmt.Errorf("pb.toml missing [pocketbase].service_name")
	}

	serverIP := cfg.Server.IP
	if serverIP == "" {
		return fmt.Errorf("pb.toml missing [server].ip")
	}

	domain := cfg.Server.Domain
	if domain == "" {
		return fmt.Errorf("pb.toml missing [server].domain")
	}

	port := cfg.Server.Port
	if port <= 0 {
		return fmt.Errorf("pb.toml server.port must be greater than zero")
	}

	version := cfg.PocketBase.Version
	if version == "" {
		version = defaultPocketbaseVersion
	}

	serviceDir := renderServiceTemplate(defaultServiceDirTemplate, serviceName)
	envFile := renderServiceTemplate(defaultEnvFileTemplate, serviceName)
	unitServiceDir := renderServiceTemplate(defaultServiceDirTemplate, "%i")
	unitEnvFile := renderServiceTemplate(defaultEnvFileTemplate, "%i")

	step := 1
	printStep(step, totalDeploySteps, "validating configuration")
	step++
	printStep(step, totalDeploySteps, "probing remote host")
	remoteOS, err := runSSHOutput(serverIP, "/bin/uname -s")
	if err != nil {
		return fmt.Errorf("failed to determine remote OS: %w", err)
	}
	if !strings.EqualFold(remoteOS, "linux") {
		return fmt.Errorf("unsupported remote OS %q", remoteOS)
	}

	machineArch, err := runSSHOutput(serverIP, "/bin/uname -m")
	if err != nil {
		return fmt.Errorf("failed to determine remote architecture: %w", err)
	}
	arch, err := translateMachineArch(machineArch)
	if err != nil {
		return err
	}

	assetName := pocketbaseAsset(version, "linux", arch)
	assetURL := fmt.Sprintf("https://github.com/pocketbase/pocketbase/releases/download/v%s/%s", version, assetName)

	step++
	printStep(step, totalDeploySteps, "configuring firewall")
	if err := runSSHCommand(serverIP, firewallScript(port)); err != nil {
		return fmt.Errorf("firewall setup failed: %w", err)
	}

	step++
	printStep(step, totalDeploySteps, "installing caddy")
	if err := runSSHCommand(serverIP, caddyScript(domain, port, serviceName)); err != nil {
		return fmt.Errorf("caddy setup failed: %w", err)
	}

	step++
	printStep(step, totalDeploySteps, "deploying PocketBase binary")
	if err := runSSHCommand(serverIP, pocketbaseSetupScript(serviceDir, envFile, version, assetURL, port)); err != nil {
		return fmt.Errorf("PocketBase setup failed: %w", err)
	}

	step++
	printStep(step, totalDeploySteps, "syncing migrations/hooks/static assets")
	if err := syncLocalDirectories(serverIP, serviceDir, []string{"pb_migrations", "pb_hooks", "pb_public"}); err != nil {
		return fmt.Errorf("asset sync failed: %w", err)
	}

	step++
	printStep(step, totalDeploySteps, "configuring systemd service")
	if err := runSSHCommand(serverIP, systemdScript(unitServiceDir, unitEnvFile, serviceName)); err != nil {
		return fmt.Errorf("systemd setup failed: %w", err)
	}

	fmt.Printf("\nDeployment complete; PocketBase should be reachable at https://%s\n", domain)
	return nil
}

func loadPBConfig(path string) (*pbToml, error) {
	data, err := os.ReadFile(path)
	if err != nil {
		return nil, err
	}

	var cfg pbToml
	if err := toml.Unmarshal(data, &cfg); err != nil {
		return nil, fmt.Errorf("failed to parse pb.toml: %w", err)
	}
	return &cfg, nil
}

func printStep(idx, total int, message string) {
	fmt.Printf("\nStep %d/%d: %s\n", idx, total, message)
}

func renderServiceTemplate(tpl, serviceName string) string {
	return strings.ReplaceAll(tpl, "{service}", serviceName)
}

func translateMachineArch(value string) (string, error) {
	machine := strings.TrimSpace(strings.ToLower(value))
	switch machine {
	case "x86_64", "amd64":
		return "amd64", nil
	case "i386", "i486", "i586", "i686":
		return "386", nil
	case "armv7l":
		return "armv7", nil
	case "armv6l":
		return "arm", nil
	case "aarch64", "arm64":
		return "arm64", nil
	}
	return "", fmt.Errorf("unsupported remote architecture %q", value)
}

func pocketbaseAsset(version, osName, arch string) string {
	return fmt.Sprintf("pocketbase_%s_%s_%s.zip", version, osName, arch)
}

func firewallScript(port int) string {
	return fmt.Sprintf(`set -euo pipefail
if ! command -v ufw >/dev/null; then
  apt-get update -y
  apt-get install -y ufw
fi
ufw allow OpenSSH
ufw allow %d/tcp
ufw allow 80/tcp
ufw allow 443/tcp
ufw --force enable
`, port)
}

func caddyScript(domain string, port int, serviceName string) string {
	return fmt.Sprintf(`set -euo pipefail
if ! command -v caddy >/dev/null; then
  apt-get update -y
  apt-get install -y curl gnupg2
  curl -1sLf 'https://dl.cloudsmith.io/public/caddy/stable/gpg.key' | gpg --dearmor -o /usr/share/keyrings/caddy-stable-archive-keyring.gpg
  curl -1sLf 'https://dl.cloudsmith.io/public/caddy/stable/debian.deb.txt' > /etc/apt/sources.list.d/caddy-stable.list
  apt-get update -y
  apt-get install -y caddy
fi
mkdir -p /etc/caddy/sites
cat <<'EOF' > /etc/caddy/Caddyfile
import /etc/caddy/sites/*.caddy
EOF
cat <<'EOF' > /etc/caddy/sites/pb-%s.caddy
%s {
	request_body {
    max_size 10MB
  }
  encode gzip
  reverse_proxy 127.0.0.1:%d {
  	transport http {
      read_timeout 360s
    }
  }
}
EOF
systemctl daemon-reload
systemctl enable --now caddy.service
systemctl reload-or-restart caddy.service
`, serviceName, domain, port)
}

func pocketbaseSetupScript(serviceDir, envFile, version, assetURL string, port int) string {
	return fmt.Sprintf(`set -euo pipefail
service_dir="%s"
mkdir -p "$service_dir"
apt-get update -y
apt-get install -y curl unzip
binary="%s/pocketbase"
if [ ! -x "$binary" ]; then
  tmp=$(mktemp)
  curl -fsSL -o "$tmp" "%s"
  unzip -p "$tmp" pocketbase > "$binary"
  chmod +x "$binary"
  rm -f "$tmp"
fi
env_file="%s"
current_port=""
if [ -f "$env_file" ]; then
  current_port=$(grep '^PORT=' "$env_file" | head -n 1 | cut -d= -f2)
fi
if [ "$current_port" != "%d" ]; then
  cat <<'EOF' > "$env_file"
PORT=%d
EOF
fi
`, serviceDir, serviceDir, assetURL, envFile, port, port)
}

func systemdScript(serviceDir, envFile, serviceName string) string {
	return fmt.Sprintf(`set -euo pipefail
cat <<'EOF' > /etc/systemd/system/pb@.service
[Unit]
Description=PocketBase instance %%i
After=network.target

[Service]
User=root
Group=root
WorkingDirectory=%s
EnvironmentFile=%s
ExecStart=%s/pocketbase serve --http="127.0.0.1:${PORT}"
Restart=on-failure
LimitNOFILE=65535

[Install]
WantedBy=multi-user.target
EOF
systemctl daemon-reload
systemctl enable --now pb@%s
systemctl restart pb@%s
`, serviceDir, envFile, serviceDir, serviceName, serviceName)
}

func runSSHCommand(server, script string) error {
	cmd := exec.Command("ssh", append(sshArgs(server), "bash", "-lc", script)...)
	cmd.Stdout = os.Stdout
	cmd.Stderr = os.Stderr
	return cmd.Run()
}

func runSSHOutput(server, script string) (string, error) {
	cmd := exec.Command("ssh", append(sshArgs(server), "bash", "-lc", script)...)
	var out bytes.Buffer
	cmd.Stdout = &out
	cmd.Stderr = os.Stderr
	if err := cmd.Run(); err != nil {
		return "", err
	}
	return strings.TrimSpace(out.String()), nil
}

func syncLocalDirectories(server, remoteBase string, dirs []string) error {
	for _, dir := range dirs {
		localPath := filepath.Join(".", dir)
		info, err := os.Stat(localPath)
		if err != nil {
			if errors.Is(err, os.ErrNotExist) {
				fmt.Printf("- %s does not exist locally, skipping\n", dir)
				continue
			}
			return err
		}
		if !info.IsDir() {
			fmt.Printf("- %s exists but is not a directory, skipping\n", dir)
			continue
		}

		remotePath := fmt.Sprintf("root@%s:%s/%s", server, remoteBase, dir)
		cmd := exec.Command("rsync", "-e", "ssh -o BatchMode=yes -o StrictHostKeyChecking=accept-new", "-az", "--delete", localPath+"/", remotePath)
		cmd.Stdout = os.Stdout
		cmd.Stderr = os.Stderr
		if err := cmd.Run(); err != nil {
			return err
		}
	}
	return nil
}

func sshArgs(server string) []string {
	return []string{
		"-o", "BatchMode=yes",
		"-o", "StrictHostKeyChecking=accept-new",
		fmt.Sprintf("root@%s", server),
	}
}