package main

import (
	"fmt"
	"os"
	"os/exec"
	"strings"
)

// dependency contains the command name and a URL for installation instructions.
type dependency struct {
	name       string
	installURL string
}

// checkCommandExists returns true if the given command exists in the PATH.
// If it does not exist, then it prints an instruction message.
func checkCommandExists(dep dependency) bool {
	if _, err := exec.LookPath(dep.name); err != nil {
		fmt.Printf("Dependency missing: %s\n", dep.name)
		fmt.Printf("  Please install from: %s\n\n", dep.installURL)
		return false
	}
	return true
}

// ensureDependencies checks that all required tools are installed and then
// runs the 'go install' command to install the specified packages.
func ensureDependencies() error {
	// List your dependencies along with links to instructions.
	dependencies := []dependency{
		{"protoc", "https://github.com/protocolbuffers/protobuf/releases"},
		{"go", "https://go.dev/doc/install"},
		{"node", "https://nodejs.org/en/download"},
		{"npm", "https://nodejs.org/en/download"},
	}

	missing := false
	for _, dep := range dependencies {
		if !checkCommandExists(dep) {
			missing = true
		}
	}
	if missing {
		return fmt.Errorf("one or more dependencies are missing; please install them before proceeding")
	}

	// Run the 'go install' command.
	// We list all packages as arguments. This command is common on all platforms.
	toInstall := []string{
		"github.com/grpc-ecosystem/grpc-gateway/v2/protoc-gen-grpc-gateway@latest",
		"github.com/grpc-ecosystem/grpc-gateway/v2/protoc-gen-openapiv2@latest",
		"google.golang.org/protobuf/cmd/protoc-gen-go@latest",
		"google.golang.org/grpc/cmd/protoc-gen-go-grpc@latest",
	}

	fmt.Println("All dependencies found. Running:")
	fmt.Printf("  go install \n\t%s\n", strings.Join(toInstall, "\n\t"))

	for _, pkg := range toInstall {
		cmd := exec.Command("go", "install", pkg)
		// Inherit stdout/stderr so you can see the output.
		cmd.Stdout = os.Stdout
		cmd.Stderr = os.Stderr
		err := cmd.Run()
		if err != nil {
			return fmt.Errorf("failed to run go install command for package %s: %w", pkg, err)
		}
	}

	fmt.Println("Installation of protoc plugins completed successfully.")
	return nil
}