import * as vscode from 'vscode';

export class TplHoverProvider implements vscode.HoverProvider {
    public async provideHover(document: vscode.TextDocument, position: vscode.Position, token: vscode.CancellationToken): Promise<vscode.Hover | null> {
        const range = document.getWordRangeAtPosition(position, /[a-zA-Z0-9_.]+/);
        if (!range) return null;
        
        const word = document.getText(range); // z.B. "modelling.testDefine"
        const text = document.getText();
        const lines = text.split('\n');

        const parts = word.split('.');
        const importBase = parts[0];
        const funcName = parts.length > 1 ? parts[1] : word;

        // 1. Lokale Defines
        if (parts.length === 1 || parts.length === 2) {
            for (let i = 0; i < lines.length; i++) {
                const line = lines[i];
                const defMatch = line.match(new RegExp(`^\\s*define\\s+${funcName}\\b(?:\\s*\\((.*?)\\))?`));
                if (defMatch) {
                    const params = defMatch[1] ? defMatch[1].trim() : '';
                    const md = new vscode.MarkdownString();
                    md.appendCodeblock(`define ${funcName}(${params})`, 'tpl');
                    
                    const textAfterDefine = text.substring(text.indexOf(line) + line.length);
                    const docMatch = textAfterDefine.match(/^\s*(?:"""|''')([\s\S]*?)(?:"""|''')/);
                    if (docMatch) { md.appendMarkdown(`\n\n---\n\n${docMatch[1].trim()}`); }
                    
                    return new vscode.Hover(md);
                }
            }
        }

        // 2. Cross-File Hover für from ... import
        const fromImportRegex = new RegExp(`from\\s+([a-zA-Z0-9_.]+)\\s+import\\s+${importBase}\\b`);
        const fromMatch = text.match(fromImportRegex);
        if (fromMatch) {
            const moduleName = fromMatch[1];
            
            // Wenn der User über die Methode fährt (modelling.XYZ)
            if (funcName !== importBase) {
                const files = await vscode.workspace.findFiles('**/*.tpl', '**/node_modules/**');
                for (const file of files) {
                    const doc = await vscode.workspace.openTextDocument(file);
                    const docText = doc.getText();
                    if (new RegExp(`tpl\\s+1\\.\\d+\\s+module\\s+${moduleName.replace(/\./g, '\\.')}\\s*;`).test(docText)) {
                        const docLines = docText.split('\n');
                        for (let i = 0; i < docLines.length; i++) {
                            const line = docLines[i];
                            const defMatch = line.match(new RegExp(`^\\s*define\\s+${funcName}\\b(?:\\s*\\((.*?)\\))?`));
                            if (defMatch) {
                                const params = defMatch[1] ? defMatch[1].trim() : '';
                                const md = new vscode.MarkdownString();
                                md.appendCodeblock(`define ${funcName}(${params})`, 'tpl');
                                
                                const textAfterDefine = docText.substring(docText.indexOf(line) + line.length);
                                const docMatch = textAfterDefine.match(/^\s*(?:"""|''')([\s\S]*?)(?:"""|''')/);
                                if (docMatch) { md.appendMarkdown(`\n\n---\n\n${docMatch[1].trim()}`); }
                                md.appendMarkdown(`\n\n*(Importiert aus \`${moduleName}\`)*`);
                                return new vscode.Hover(md);
                            }
                        }
                    }
                }
            }
            // Wenn er nur über "modelling" fährt
            return new vscode.Hover(new vscode.MarkdownString(`Importierte Definitions **${importBase}** aus Modul \`${moduleName}\`.`));
        }

        // 3. Hover für Built-Ins
        if (word.startsWith('log.')) { return new vscode.Hover(new vscode.MarkdownString(`TPL Logging-Modul`)); }
        if (word.startsWith('discovery.')) { return new vscode.Hover(new vscode.MarkdownString(`TPL Discovery-Modul`)); }

        return null;
    }
}