package linter

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

	"gmgauthier.com/grokkit/internal/logger"
)

// Language represents a programming language
type Language struct {
	Name       string
	Extensions []string
	Linters    []Linter
}

// Linter represents a linting tool
type Linter struct {
	Name        string
	Command     string
	Args        []string
	InstallInfo string
}

// LintResult contains linting results
type LintResult struct {
	Language     string
	LinterUsed   string
	Output       string
	ExitCode     int
	HasIssues    bool
	LinterExists bool
}

// Supported languages and their linters
var languages = []Language{
	{
		Name:       "Go",
		Extensions: []string{".go"},
		Linters: []Linter{
			{
				Name:        "golangci-lint",
				Command:     "golangci-lint",
				Args:        []string{"run"},
				InstallInfo: "https://golangci-lint.run/usage/install/",
			},
			{
				Name:        "go vet",
				Command:     "go",
				Args:        []string{"vet"},
				InstallInfo: "Built-in with Go",
			},
		},
	},
	{
		Name:       "Python",
		Extensions: []string{".py"},
		Linters: []Linter{
			{
				Name:        "pylint",
				Command:     "pylint",
				Args:        []string{},
				InstallInfo: "pip install pylint",
			},
			{
				Name:        "flake8",
				Command:     "flake8",
				Args:        []string{},
				InstallInfo: "pip install flake8",
			},
			{
				Name:        "ruff",
				Command:     "ruff",
				Args:        []string{"check"},
				InstallInfo: "pip install ruff",
			},
		},
	},
	{
		Name:       "JavaScript",
		Extensions: []string{".js", ".jsx"},
		Linters: []Linter{
			{
				Name:        "eslint",
				Command:     "eslint",
				Args:        []string{},
				InstallInfo: "npm install -g eslint",
			},
		},
	},
	{
		Name:       "TypeScript",
		Extensions: []string{".ts", ".tsx"},
		Linters: []Linter{
			{
				Name:        "eslint",
				Command:     "eslint",
				Args:        []string{},
				InstallInfo: "npm install -g eslint @typescript-eslint/parser",
			},
			{
				Name:        "tsc",
				Command:     "tsc",
				Args:        []string{"--noEmit"},
				InstallInfo: "npm install -g typescript",
			},
		},
	},
	{
		Name:       "Rust",
		Extensions: []string{".rs"},
		Linters: []Linter{
			{
				Name:        "clippy",
				Command:     "cargo",
				Args:        []string{"clippy", "--"},
				InstallInfo: "rustup component add clippy",
			},
		},
	},
	{
		Name:       "Ruby",
		Extensions: []string{".rb"},
		Linters: []Linter{
			{
				Name:        "rubocop",
				Command:     "rubocop",
				Args:        []string{},
				InstallInfo: "gem install rubocop",
			},
		},
	},
	{
		Name:       "Java",
		Extensions: []string{".java"},
		Linters: []Linter{
			{
				Name:        "checkstyle",
				Command:     "checkstyle",
				Args:        []string{"-c", "/google_checks.xml"},
				InstallInfo: "https://checkstyle.org/",
			},
		},
	},
	{
		Name:       "C/C++",
		Extensions: []string{".c", ".cpp", ".cc", ".cxx", ".h", ".hpp"},
		Linters: []Linter{
			{
				Name:        "clang-tidy",
				Command:     "clang-tidy",
				Args:        []string{},
				InstallInfo: "apt install clang-tidy or brew install llvm",
			},
		},
	},
	{
		Name:       "Shell",
		Extensions: []string{".sh", ".bash"},
		Linters: []Linter{
			{
				Name:        "shellcheck",
				Command:     "shellcheck",
				Args:        []string{},
				InstallInfo: "apt install shellcheck or brew install shellcheck",
			},
		},
	},
}

// DetectLanguage detects the programming language based on file extension
func DetectLanguage(filePath string) (*Language, error) {
	ext := strings.ToLower(filepath.Ext(filePath))

	logger.Debug("detecting language", "file", filePath, "extension", ext)

	for i := range languages {
		for _, langExt := range languages[i].Extensions {
			if ext == langExt {
				logger.Info("language detected", "file", filePath, "language", languages[i].Name)
				return &languages[i], nil
			}
		}
	}

	return nil, fmt.Errorf("unsupported file type: %s", ext)
}

// CheckLinterAvailable checks if a linter command is available
func CheckLinterAvailable(linter Linter) bool {
	_, err := exec.LookPath(linter.Command)
	available := err == nil
	logger.Debug("checking linter availability",
		"linter", linter.Name,
		"command", linter.Command,
		"available", available)
	return available
}

// FindAvailableLinter finds the first available linter for a language
func FindAvailableLinter(lang *Language) (*Linter, error) {
	logger.Info("searching for available linter", "language", lang.Name, "options", len(lang.Linters))

	for i := range lang.Linters {
		if CheckLinterAvailable(lang.Linters[i]) {
			logger.Info("found available linter",
				"language", lang.Name,
				"linter", lang.Linters[i].Name)
			return &lang.Linters[i], nil
		}
	}

	// Build install instructions
	installOptions := make([]string, 0, len(lang.Linters))
	for _, linter := range lang.Linters {
		installOptions = append(installOptions,
			fmt.Sprintf("  - %s: %s", linter.Name, linter.InstallInfo))
	}

	return nil, fmt.Errorf("no linter found for %s\n\nInstall one of:\n%s",
		lang.Name, strings.Join(installOptions, "\n"))
}

// RunLinter executes the linter on the specified file
func RunLinter(filePath string, linter Linter) (*LintResult, error) {
	logger.Info("running linter",
		"file", filePath,
		"linter", linter.Name,
		"command", linter.Command)

	// Build command arguments
	linterArgs := append([]string{}, linter.Args...)
	linterArgs = append(linterArgs, filePath)

	// Execute linter
	// nolint:gosec // intentional subprocess for linter
	cmd := exec.Command(linter.Command, linterArgs...)
	output, err := cmd.CombinedOutput()

	result := &LintResult{
		LinterUsed:   linter.Name,
		Output:       string(output),
		LinterExists: true,
	}

	if err != nil {
		var exitErr *exec.ExitError
		if errors.As(err, &exitErr) {
			result.ExitCode = exitErr.ExitCode()
			result.HasIssues = true
			logger.Info("linter found issues",
				"linter", linter.Name,
				"exit_code", result.ExitCode,
				"output_length", len(output))
		} else {
			logger.Error("linter execution failed",
				"linter", linter.Name,
				"error", err)
			return nil, fmt.Errorf("failed to execute %s: %w", linter.Name, err)
		}
	} else {
		result.ExitCode = 0
		result.HasIssues = false
		logger.Info("linter passed with no issues", "linter", linter.Name)
	}

	return result, nil
}

// LintFile detects language and runs appropriate linter
func LintFile(filePath string) (*LintResult, error) {
	// Check file exists
	if _, err := os.Stat(filePath); os.IsNotExist(err) {
		return nil, fmt.Errorf("file not found: %s", filePath)
	}

	// Detect language
	lang, err := DetectLanguage(filePath)
	if err != nil {
		return nil, err
	}

	// Find available linter
	linter, err := FindAvailableLinter(lang)
	if err != nil {
		return &LintResult{
			Language:     lang.Name,
			LinterExists: false,
			Output:       err.Error(),
		}, err
	}

	// Run linter
	result, err := RunLinter(filePath, *linter)
	if err != nil {
		return nil, err
	}

	result.Language = lang.Name
	return result, nil
}

// GetSupportedLanguages returns a list of all supported languages
func GetSupportedLanguages() []string {
	langs := make([]string, 0, len(languages))
	for _, lang := range languages {
		langs = append(langs, fmt.Sprintf("%s (%s)", lang.Name, strings.Join(lang.Extensions, ", ")))
	}
	return langs
}