using System;
using System.IO;
using System.Linq;

namespace MarketAlly.ProjectDetector
{
    /// <summary>
    /// Locates the best project or solution file to index/analyze in a given directory
    /// </summary>
    public static class ProjectFileLocator
    {
        /// <summary>
        /// Finds the best file to index based on the project type
        /// </summary>
        public static string FindBestFileToIndex(string projectPath, ProjectType projectType, bool ignoreSolution)
        {
            if (!ignoreSolution)
            {
                // Look for solution files first (they're usually the best to index)
                var solutionFiles = Directory.GetFiles(projectPath, "*.sln", SearchOption.TopDirectoryOnly);
                if (solutionFiles.Any())
                {
                    return Path.GetFullPath(solutionFiles.First());
                }
            }

            // Based on project type, look for appropriate project files
            switch (projectType)
            {
                // .NET project types
                case ProjectType.API:
                case ProjectType.WebApp:
                case ProjectType.Library:
                case ProjectType.Service:
                case ProjectType.Tests:
                case ProjectType.WpfApp:
                case ProjectType.WinFormsApp:
                case ProjectType.MobileApp:
                case ProjectType.Function:
                case ProjectType.Standalone:
                case ProjectType.Tool:
                case ProjectType.Plugin:
                case ProjectType.ChatBot:
                    return FindDotNetProjectFile(projectPath) ?? projectPath;

                // Node.js project types
                case ProjectType.ReactApp:
                case ProjectType.VueApp:
                case ProjectType.AngularApp:
                case ProjectType.NextJsApp:
                case ProjectType.NodeJsApi:
                case ProjectType.NodeJsApp:
                case ProjectType.ElectronApp:
                    // For Node projects, the directory itself is usually the best option
                    // as package.json defines the project
                    return projectPath;

                // Python project types
                case ProjectType.DjangoApp:
                case ProjectType.FlaskApp:
                case ProjectType.PythonApp:
                    return FindPythonProjectFile(projectPath) ?? projectPath;

                // Java project types
                case ProjectType.JavaMavenProject:
                    return FindMavenProjectFile(projectPath) ?? projectPath;

                case ProjectType.JavaGradleProject:
                    return FindGradleProjectFile(projectPath) ?? projectPath;

                // Go projects
                case ProjectType.GoApp:
                    var goMod = Path.Combine(projectPath, "go.mod");
                    return File.Exists(goMod) ? goMod : projectPath;

                // Rust projects
                case ProjectType.RustApp:
                    var cargoToml = Path.Combine(projectPath, "Cargo.toml");
                    return File.Exists(cargoToml) ? cargoToml : projectPath;

                // Game development
                case ProjectType.UnityProject:
                    // Unity projects are defined by the directory containing Assets folder
                    var assetsFolder = Path.Combine(projectPath, "Assets");
                    return Directory.Exists(assetsFolder) ? projectPath : projectPath;

                case ProjectType.UnrealProject:
                    // Look for .uproject files
                    var uprojectFiles = Directory.GetFiles(projectPath, "*.uproject", SearchOption.TopDirectoryOnly);
                    return uprojectFiles.FirstOrDefault() ?? projectPath;

                case ProjectType.GodotProject:
                    // Look for project.godot file
                    var godotProject = Path.Combine(projectPath, "project.godot");
                    return File.Exists(godotProject) ? projectPath : projectPath;

                default:
                    // For unknown types, try to find any common project file
                    return FindAnyIndexableFile(projectPath, ignoreSolution);
            }
        }

        /// <summary>
        /// Finds any indexable file when project type is unknown or manually overridden
        /// </summary>
        public static string FindAnyIndexableFile(string projectPath, bool ignoreSolution)
        {
            // 1. Look for solution files first (highest priority)
            if (!ignoreSolution)
            {
                var solutionFiles = Directory.GetFiles(projectPath, "*.sln", SearchOption.TopDirectoryOnly);
                if (solutionFiles.Any())
                {
                    return Path.GetFullPath(solutionFiles.First());
                }
            }

            // 2. Look for .NET project files
            var dotnetProject = FindDotNetProjectFile(projectPath);
            if (dotnetProject != null)
            {
                return dotnetProject;
            }

            // 3. Check for package.json (Node.js projects)
            var packageJson = Path.Combine(projectPath, "package.json");
            if (File.Exists(packageJson))
            {
                return projectPath; // For Node projects, index the directory
            }

            // 4. Check for Python project files
            var pythonProject = FindPythonProjectFile(projectPath);
            if (pythonProject != null)
            {
                return pythonProject;
            }

            // 5. Check for Java project files
            var mavenProject = FindMavenProjectFile(projectPath);
            if (mavenProject != null)
            {
                return mavenProject;
            }

            var gradleProject = FindGradleProjectFile(projectPath);
            if (gradleProject != null)
            {
                return gradleProject;
            }

            // 6. Check for Go modules
            var goMod = Path.Combine(projectPath, "go.mod");
            if (File.Exists(goMod))
            {
                return goMod;
            }

            // 7. Check for Rust projects
            var cargoToml = Path.Combine(projectPath, "Cargo.toml");
            if (File.Exists(cargoToml))
            {
                return cargoToml;
            }

            // 8. Check for requirements.txt (generic Python projects)
            var requirementsTxt = Path.Combine(projectPath, "requirements.txt");
            if (File.Exists(requirementsTxt))
            {
                return projectPath;
            }

            // Default: Just return the directory for analysis
            return projectPath;
        }

        private static string? FindDotNetProjectFile(string projectPath)
        {
            var projectFiles = Directory.GetFiles(projectPath, "*.csproj", SearchOption.AllDirectories)
                .Concat(Directory.GetFiles(projectPath, "*.vbproj", SearchOption.AllDirectories))
                .Concat(Directory.GetFiles(projectPath, "*.fsproj", SearchOption.AllDirectories))
                .OrderBy(f => f.Count(c => c == Path.DirectorySeparatorChar)) // Prefer files closer to root
                .FirstOrDefault();
            
            // Normalize the path if found
            return projectFiles != null ? Path.GetFullPath(projectFiles) : null;
        }

        private static string? FindPythonProjectFile(string projectPath)
        {
            // Check for setup.py
            var setupPy = Path.Combine(projectPath, "setup.py");
            if (File.Exists(setupPy))
                return setupPy;
            
            // Check for pyproject.toml
            var pyprojectToml = Path.Combine(projectPath, "pyproject.toml");
            if (File.Exists(pyprojectToml))
                return pyprojectToml;

            // Check for setup.cfg
            var setupCfg = Path.Combine(projectPath, "setup.cfg");
            if (File.Exists(setupCfg))
                return projectPath;

            return null;
        }

        private static string? FindMavenProjectFile(string projectPath)
        {
            var pomFile = Directory.GetFiles(projectPath, "pom.xml", SearchOption.AllDirectories)
                .OrderBy(f => f.Count(c => c == Path.DirectorySeparatorChar))
                .FirstOrDefault();
            
            return pomFile != null ? Path.GetFullPath(pomFile) : null;
        }

        private static string? FindGradleProjectFile(string projectPath)
        {
            var buildGradle = Directory.GetFiles(projectPath, "build.gradle", SearchOption.AllDirectories)
                .OrderBy(f => f.Count(c => c == Path.DirectorySeparatorChar))
                .FirstOrDefault();
            
            if (buildGradle != null)
                return Path.GetFullPath(buildGradle);

            // Also check for build.gradle.kts (Kotlin DSL)
            var buildGradleKts = Directory.GetFiles(projectPath, "build.gradle.kts", SearchOption.AllDirectories)
                .OrderBy(f => f.Count(c => c == Path.DirectorySeparatorChar))
                .FirstOrDefault();
                
            return buildGradleKts != null ? Path.GetFullPath(buildGradleKts) : null;
        }
    }
}