package spitfire

import (
	"fmt"
	"os"
	"os/exec"
	"path/filepath"
	"runtime"
	"strings"
	"sync"
)

var (
	reportedCommands = make(map[string]bool)
	reportMutex      sync.Mutex
)

// CheckDependencies ensures that all required tools and dependencies for the build are installed.
func CheckDependencies() error {
	// Just to make sure, reset reported commands at start
	reportMutex.Lock()
	reportedCommands = make(map[string]bool)
	reportMutex.Unlock()

	// Common dependencies
	dependencies := map[string]string{
		"git":    "https://git-scm.com/downloads",             // Git
		"python": "https://www.python.org/downloads/",         // Python
		"pip3":   "https://pip.pypa.io/en/stable/installing/", // Pip3
		"hg":     "https://www.mercurial-scm.org/",            // Mercurial (hg)
		"rustc":  "https://www.rust-lang.org/tools/install",   // Rust compiler
		"cargo":  "https://www.rust-lang.org/tools/install",   // Cargo package manager
	}

	// Add platform-specific dependencies
	if runtime.GOOS == "windows" {
		mozBuildPath := os.Getenv("MOZILLABUILD")
		if mozBuildPath == "" {
			mozBuildPath = "C:\\mozilla-build" // Default path for MozillaBuild on Windows
		}
		if !dirExists(mozBuildPath) {
			dependencies["mozbuild"] = "https://ftp.mozilla.org/pub/mozilla/libraries/win32/MozillaBuildSetup-Latest.exe"
		}
	} else {
		dependencies["rsync"] = "https://rsync.samba.org/download.html" // rsync for non-Windows platforms
	}

	// Check for missing tools
	missingTools := []string{}
	for tool, downloadLink := range dependencies {
		if !isCommandAvailable(tool) {
			missingTools = append(missingTools, fmt.Sprintf("%s (Download: %s)", tool, downloadLink))
		}
	}

	// Check Rust version if installed
	if isCommandAvailable("rustc") {
		_, err := getCommandOutput("rustc", "--version")
		if err != nil {
			missingTools = append(missingTools, "rustc (version check failed)")
		}
	}

	// Check for `mach` script in the source directory
	machPath := filepath.Join("mozilla-release", "mach")
	repoExists, err := CheckRepoExists("mozilla-release")
	if err != nil {
		// Repository exists but is corrupted
		fmt.Println("⚠️ Existing repository appears corrupted")
	}

	if !fileExists(machPath) {
		if len(missingTools) == 0 {
			// Only mach is missing and other dependencies are satisfied - try to clone
			fmt.Println("⚠️ mach script missing - attempting to clone repository...")
			if err := CloneRepo("mozilla-release", "https://hg.mozilla.org/releases/mozilla-release/"); err != nil {
				missingTools = append(missingTools, "mach (failed to automatically clone repository)")
			} else {
				// Verify mach exists after clone
				if !fileExists(machPath) {
					missingTools = append(missingTools, "mach (repository cloned but mach still missing)")
				} else {
					fmt.Println("✅ Successfully cloned repository and found mach script")
				}
			}
		} else {
			// Other tools are also missing - just report mach as missing
			if !repoExists {
				missingTools = append(missingTools, "mach (repository not found)")
			} else {
				missingTools = append(missingTools, "mach (found repository but mach is missing)")
			}
		}
	}

	// Report missing tools if any
	if len(missingTools) > 0 {
		fmt.Println("The following tools are missing and are required for the build:")
		for _, tool := range missingTools {
			fmt.Println(" - " + tool)
		}
		return fmt.Errorf("missing required tools")
	}

	fmt.Println("All required system dependencies are installed.")
	return nil
}

// CheckRepoExists verifies if the Mozilla repository exists and is valid
func CheckRepoExists(sourcePath string) (bool, error) {
	hgDir := filepath.Join(sourcePath, ".hg")
	if _, err := os.Stat(hgDir); os.IsNotExist(err) {
		return false, nil
	}
	return true, nil
}

// isCommandAvailable checks if a command/tool is available on the system.
func isCommandAvailable(command string) bool {
	path, err := exec.LookPath(command)
	if err != nil {
		return false
	}

	reportMutex.Lock()
	defer reportMutex.Unlock()

	if !reportedCommands[command] {
		fmt.Printf("Command '%s' found at path '%s'\n", command, path)
		reportedCommands[command] = true
	}
	return true
}

// Helper function to get command output
func getCommandOutput(name string, arg ...string) (string, error) {
	cmd := exec.Command(name, arg...)
	output, err := cmd.CombinedOutput()
	if err != nil {
		return "", err
	}
	return string(output), nil
}

// fileExists checks if a file exists at the given path.
func fileExists(path string) bool {
	_, err := os.Stat(path)
	return err == nil
}

// dirExists checks if a directory exists at the given path.
func dirExists(path string) bool {
	info, err := os.Stat(path)
	if os.IsNotExist(err) {
		return false
	}
	return info.IsDir()
}

// isMsys2 detects if the environment is MSYS2 by checking the MSYSTEM environment variable.
func isMsys2() bool {
	return strings.Contains(strings.ToLower(os.Getenv("MSYSTEM")), "msys")
}