package main

import (
	"archive/zip"
	"errors"
	"fmt"
	"io"
	"log"
	"math/rand"
	"net/http"
	"os"
	"path/filepath"
	"runtime"
	"strings"
	"time"

	"github.com/urfave/cli/v2"
)

func main() {
	app := &cli.App{
		Name:  "pb",
		Usage: "PocketBase deployment helper",
		Commands: []*cli.Command{
			{
				Name:   "init",
				Usage:  "start a new PocketBase project",
				Action: initAction(),
			},
			{
				Name:   "deploy",
				Usage:  "deploy the PocketBase project",
				Action: placeholderAction("deploy"),
			},
			{
				Name:   "logs",
				Usage:  "show PocketBase logs",
				Action: placeholderAction("logs"),
			},
			{
				Name:   "secrets",
				Usage:  "manage deployment secrets",
				Action: placeholderAction("secrets"),
			},
		},
	}

	if err := app.Run(os.Args); err != nil {
		log.Fatal(err)
	}
}

func placeholderAction(name string) func(*cli.Context) error {
	return func(c *cli.Context) error {
		fmt.Printf("TODO: implement %s command\n", name)
		return nil
	}
}

func initAction() func(*cli.Context) error {
	return func(c *cli.Context) error {
		cwd, err := os.Getwd()
		if err != nil {
			return err
		}

		pbPath := filepath.Join(cwd, "pb.toml")
		if _, err := os.Stat(pbPath); err == nil {
			return fmt.Errorf("pb.toml already exists, aborting")
		} else if !errors.Is(err, os.ErrNotExist) {
			return err
		}

		serviceName := generateServiceName()

		if err := writePBConfig(pbPath, serviceName); err != nil {
			return err
		}

		targetDir := filepath.Join(cwd, "bin")
		if err := os.MkdirAll(targetDir, 0o755); err != nil {
			return err
		}

		binaryPath := filepath.Join(targetDir, pocketbaseBinaryName(runtime.GOOS))
		if err := downloadPocketbase(defaultPocketbaseVersion, runtime.GOOS, runtime.GOARCH, binaryPath); err != nil {
			return err
		}

		if err := ensureGitignoreEntries(filepath.Join(cwd, ".gitignore"), []string{"bin/pocketbase", "pb.toml"}); err != nil {
			return err
		}

		fmt.Printf("Initialized PocketBase project %q\n", serviceName)
		return nil
	}
}

const defaultPocketbaseVersion = "0.35.1"

func init() {
	rand.Seed(time.Now().UnixNano())
}

func writePBConfig(path, serviceName string) error {
	const tmpl = `[server]
ip = "127.0.0.1"
port = 8090
domain = "example.com"

[pocketbase]
version = "%s"
service_name = "%s"
`
	return os.WriteFile(path, []byte(fmt.Sprintf(tmpl, defaultPocketbaseVersion, serviceName)), 0o644)
}

func generateServiceName() string {
	adjectives := []string{"sunny", "silent", "cobalt", "rusty", "plush", "brisk", "sage", "glow"}
	nouns := []string{"harbor", "delta", "bloom", "atlas", "ripple", "ember", "lumen", "orbit"}
	adjective := adjectives[rand.Intn(len(adjectives))]
	noun := nouns[rand.Intn(len(nouns))]
	return fmt.Sprintf("%s-%s", adjective, noun)
}

func pocketbaseBinaryName(goos string) string {
	if goos == "windows" {
		return "pocketbase.exe"
	}
	return "pocketbase"
}

func downloadPocketbase(version, goos, goarch, dest string) error {
	url, binaryName, err := releaseAssetURL(version, goos, goarch)
	if err != nil {
		return err
	}

	resp, err := http.Get(url)
	if err != nil {
		return fmt.Errorf("failed to download %s: %w", url, err)
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusOK {
		return fmt.Errorf("unexpected status %s while downloading %s", resp.Status, url)
	}

	tmpFile, err := os.CreateTemp("", "pocketbase-*.zip")
	if err != nil {
		return err
	}
	defer os.Remove(tmpFile.Name())
	defer tmpFile.Close()

	if _, err := io.Copy(tmpFile, resp.Body); err != nil {
		return err
	}

	if err := extractBinary(tmpFile.Name(), binaryName, dest); err != nil {
		return err
	}

	return os.Chmod(dest, 0o755)
}

func releaseAssetURL(version, goos, goarch string) (string, string, error) {
	osName := map[string]string{
		"darwin":  "darwin",
		"linux":   "linux",
		"windows": "windows",
	}
	archName := map[string]string{
		"amd64": "amd64",
		"386":   "386",
		"arm64": "arm64",
		"arm":   "armv7",
	}

	osPart, ok := osName[goos]
	if !ok {
		return "", "", fmt.Errorf("unsupported GOOS: %s", goos)
	}
	archPart, ok := archName[goarch]
	if !ok {
		return "", "", fmt.Errorf("unsupported GOARCH: %s", goarch)
	}

	filename := fmt.Sprintf("pocketbase_%s_%s_%s.zip", version, osPart, archPart)
	url := fmt.Sprintf("https://github.com/pocketbase/pocketbase/releases/download/v%s/%s", version, filename)
	return url, pocketbaseBinaryName(goos), nil
}

func extractBinary(zipPath, binaryName, dest string) error {
	r, err := zip.OpenReader(zipPath)
	if err != nil {
		return err
	}
	defer r.Close()

	for _, f := range r.File {
		if filepath.Base(f.Name) != binaryName {
			continue
		}

		if err := os.MkdirAll(filepath.Dir(dest), 0o755); err != nil {
			return err
		}

		src, err := f.Open()
		if err != nil {
			return err
		}
		defer src.Close()

		out, err := os.OpenFile(dest, os.O_CREATE|os.O_WRONLY|os.O_TRUNC, 0o755)
		if err != nil {
			return err
		}
		defer out.Close()

		if _, err := io.Copy(out, src); err != nil {
			return err
		}

		return nil
	}
	return fmt.Errorf("binary %s not found in archive", binaryName)
}

func ensureGitignoreEntries(path string, entries []string) error {
	var existing = make(map[string]struct{})
	var original []byte
	if data, err := os.ReadFile(path); err == nil {
		original = data
		for _, line := range strings.Split(string(data), "\n") {
			trimmed := strings.TrimSpace(line)
			if trimmed != "" {
				existing[trimmed] = struct{}{}
			}
		}
	} else if !errors.Is(err, os.ErrNotExist) {
		return err
	}

	builder := &strings.Builder{}
	if len(original) > 0 {
		builder.Write(original)
		if !strings.HasSuffix(string(original), "\n") {
			builder.WriteByte('\n')
		}
	}

	var added bool
	for _, entry := range entries {
		if _, seen := existing[entry]; seen {
			continue
		}
		builder.WriteString(entry)
		builder.WriteByte('\n')
		added = true
	}

	if !added {
		return nil
	}

	return os.WriteFile(path, []byte(builder.String()), 0o644)
}