import React, { useState, useEffect } from 'react';
import { X, Github, Upload, Play, Loader2, GitBranch, Search, AlertTriangle } from 'lucide-react';
import { JulesSource } from '../types';

interface NewSessionModalProps {
  isOpen: boolean;
  onClose: () => void;
  onSubmit: (config: NewSessionConfig) => Promise<void>;
  initialPrompt: string;
  sources: JulesSource[];
  isLoading: boolean;
  githubToken?: string;
  githubProfile?: string;
}

export interface NewSessionConfig {
  title: string;
  prompt: string;
  sourceId: string; // The Jules Source Name e.g., "sources/github/..."
  githubRepoId: string; // "owner/repo" for HF API
  branch: string;
  hfImport?: {
    spaceId: string;
  };
  runHfDeploymentCue?: boolean;
}

export const NewSessionModal: React.FC<NewSessionModalProps> = ({ 
  isOpen, 
  onClose, 
  onSubmit, 
  initialPrompt, 
  sources,
  isLoading,
  githubToken,
  githubProfile
}) => {
  const [title, setTitle] = useState('');
  const [repoSearch, setRepoSearch] = useState('');
  const [isManualTitle, setIsManualTitle] = useState(false);
  const [selectedSource, setSelectedSource] = useState<JulesSource | null>(null);
  const [branch, setBranch] = useState('main');
  const [availableBranches, setAvailableBranches] = useState<string[]>([]);
  const [isLoadingBranches, setIsLoadingBranches] = useState(false);
  const [prompt, setPrompt] = useState(initialPrompt);
  const [isHfImportEnabled, setIsHfImportEnabled] = useState(false);
  const [hfSpaceId, setHfSpaceId] = useState('');
  const [runHfDeploymentCue, setRunHfDeploymentCue] = useState(false);

  // Update prompt if initialPrompt changes
  useEffect(() => {
    setPrompt(initialPrompt);
    // Auto-generate a title from prompt ONLY if no repo is set
    if (initialPrompt && !title && !repoSearch && !isManualTitle) {
        setTitle(initialPrompt.slice(0, 30) + (initialPrompt.length > 30 ? '...' : ''));
    }
  }, [initialPrompt]);

  // Handle URL transformation and Auto-Title
  useEffect(() => {
    let currentRepo = repoSearch;
    // URL transformation: https://github.com/owner/repo(.git) -> owner/repo
    const githubUrlRegex = /https?:\/\/github\.com\/([^/]+)\/([^/]+)/;
    const match = currentRepo.match(githubUrlRegex);
    if (match) {
        let repoPart = match[2].replace(/\.git$/, '');
        const transformed = `${match[1]}/${repoPart}`;
        setRepoSearch(transformed);
        currentRepo = transformed;
    }

    // Auto-Title based on repo if title is empty or not manually set
    if (!isManualTitle && currentRepo.includes('/')) {
        const repoName = currentRepo.split('/').pop() || '';
        if (repoName) {
            setTitle(repoName.charAt(0).toUpperCase() + repoName.slice(1));
        }
    }
  }, [repoSearch, isManualTitle]);

  // Handle Repo Selection and Branch Fetching
  useEffect(() => {
    const fetchBranches = async () => {
        const repoId = selectedSource
            ? `${selectedSource.githubRepo.owner}/${selectedSource.githubRepo.repo}`
            : repoSearch.includes('/') ? repoSearch : null;

        if (!repoId) {
            setAvailableBranches([]);
            return;
        }

        setIsLoadingBranches(true);
        try {
            const [owner, repo] = repoId.split('/');
            const url = `/api/github/branches?owner=${owner}&repo=${repo}${githubToken ? '&token=' + githubToken : ''}${githubProfile ? '&profile=' + githubProfile : ''}`;
            const res = await fetch(url);
            if (res.ok) {
                const data = await res.json();
                const names = data.map((b: any) => b.name);
                setAvailableBranches(names);
                if (!branch || !names.includes(branch)) {
                    setBranch(names.find((n: string) => n === 'main' || n === 'master') || names[0] || 'main');
                }
            } else {
                setAvailableBranches([]);
            }
        } catch (e) {
            console.error("Failed to fetch branches", e);
            setAvailableBranches([]);
        } finally {
            setIsLoadingBranches(false);
        }
    };

    const timer = setTimeout(fetchBranches, 500);
    return () => clearTimeout(timer);
  }, [selectedSource, repoSearch, githubToken, githubProfile]);

  // Find matching source when typing
  useEffect(() => {
      if (repoSearch.includes('/')) {
          const match = sources.find(s =>
              `${s.githubRepo.owner}/${s.githubRepo.repo}`.toLowerCase() === repoSearch.toLowerCase()
          );
          if (match) {
              setSelectedSource(match);
          } else {
              setSelectedSource(null);
          }
      }
  }, [repoSearch, sources]);

  if (!isOpen) return null;

  const handleSubmit = (e: React.FormEvent) => {
    e.preventDefault();

    // We must have a GitHub repository for Jules to use
    if (!repoSearch) {
        alert("Please enter a target GitHub repository (owner/repo).");
        return;
    }

    // We must have a Hugging Face Space ID if import is enabled
    if (isHfImportEnabled && !hfSpaceId) {
        alert("Please enter a Hugging Face Space ID to import from.");
        return;
    }

    const githubRepoId = selectedSource
        ? `${selectedSource.githubRepo.owner}/${selectedSource.githubRepo.repo}`
        : repoSearch;

    const config: NewSessionConfig = {
      title,
      prompt,
      sourceId: selectedSource?.name || `sources/github/${githubRepoId}`, // Fallback ID if not found
      githubRepoId,
      branch,
      hfImport: isHfImportEnabled ? { spaceId: hfSpaceId } : undefined,
      runHfDeploymentCue
    };

    onSubmit(config);
  };

  return (
    <div className="fixed inset-0 z-[60] flex items-center justify-center bg-black/60 backdrop-blur-sm p-4">
      <div className="bg-white rounded-2xl shadow-2xl w-full max-w-lg overflow-hidden flex flex-col max-h-[90vh]">
        <div className="p-5 border-b border-gray-100 flex justify-between items-center bg-gray-50">
          <div className="flex items-center gap-2">
            <div className="p-2 bg-indigo-100 text-indigo-600 rounded-lg">
               <Play className="w-5 h-5" />
            </div>
            <h3 className="font-bold text-gray-800">Start New Session</h3>
          </div>
          {!isLoading && (
            <button onClick={onClose} className="text-gray-400 hover:text-gray-600">
              <X className="w-5 h-5" />
            </button>
          )}
        </div>

        <form onSubmit={handleSubmit} className="p-6 overflow-y-auto space-y-5">
            {/* Session Details */}
            <div className="space-y-4">
                <div>
                    <label className="block text-sm font-semibold text-gray-700 mb-1">Session Title</label>
                    <input
                        required
                        type="text"
                        value={title}
                        onChange={(e) => {
                            setTitle(e.target.value);
                            setIsManualTitle(true);
                        }}
                        className="w-full px-4 py-2 border border-gray-200 rounded-lg focus:ring-2 focus:ring-indigo-500 outline-none"
                        placeholder="e.g. Implement Login Feature"
                        disabled={isLoading}
                    />
                </div>
                
                <div>
                    <label className="block text-sm font-semibold text-gray-700 mb-1">Initial Prompt</label>
                    <textarea
                        required
                        value={prompt}
                        onChange={(e) => setPrompt(e.target.value)}
                        className="w-full px-4 py-2 border border-gray-200 rounded-lg focus:ring-2 focus:ring-indigo-500 outline-none resize-none h-24 text-sm"
                        placeholder="What should Jules do?"
                        disabled={isLoading}
                    />
                </div>

                <div className="grid grid-cols-1 md:grid-cols-2 gap-4">
                    <div>
                        <label className="block text-sm font-semibold text-gray-700 mb-1">GitHub Source (owner/repo)</label>
                        <div className="relative">
                            <Search className="absolute left-3 top-2.5 w-4 h-4 text-gray-400" />
                            <input
                                list="source-suggestions"
                                type="text"
                                value={repoSearch}
                                onChange={(e) => setRepoSearch(e.target.value)}
                                className={`w-full pl-9 pr-3 py-2 border rounded-lg focus:ring-2 focus:ring-indigo-500 outline-none transition-colors ${
                                    selectedSource ? 'border-green-300 bg-green-50' : 'border-gray-200'
                                }`}
                                placeholder="JsonLord/agent-notes"
                                disabled={isLoading}
                            />
                            <datalist id="source-suggestions">
                                {sources.map(s => (
                                    <option key={s.name} value={`${s.githubRepo.owner}/${s.githubRepo.repo}`} />
                                ))}
                            </datalist>
                        </div>
                        {repoSearch && !selectedSource && availableBranches.length > 0 && (
                            <div className="flex items-center gap-1 mt-1 text-[10px] text-blue-600 font-bold uppercase">
                                <GitBranch className="w-3 h-3" />
                                <span>Connected via GitHub</span>
                            </div>
                        )}
                        {selectedSource && (
                            <div className="flex items-center gap-1 mt-1 text-[10px] text-green-600 font-bold uppercase">
                                <Github className="w-3 h-3" />
                                <span>Jules Source Verified</span>
                            </div>
                        )}
                    </div>
                    <div>
                        <label className="block text-sm font-semibold text-gray-700 mb-1">Branch</label>
                        <div className="relative">
                             <GitBranch className="absolute left-3 top-2.5 w-4 h-4 text-gray-400" />
                             <select
                                value={branch}
                                onChange={(e) => setBranch(e.target.value)}
                                className="w-full pl-9 pr-8 py-2 border border-gray-200 rounded-lg focus:ring-2 focus:ring-indigo-500 outline-none bg-white appearance-none text-sm"
                                disabled={isLoading || isLoadingBranches}
                             >
                                {isLoadingBranches ? (
                                    <option>Loading branches...</option>
                                ) : availableBranches.length > 0 ? (
                                    availableBranches.map(b => <option key={b} value={b}>{b}</option>)
                                ) : (
                                    <option value="main">main</option>
                                )}
                             </select>
                             {isLoadingBranches && <Loader2 className="absolute right-3 top-2.5 w-4 h-4 text-indigo-500 animate-spin" />}
                        </div>
                    </div>
                </div>
            </div>

            {/* Hugging Face Import Section */}
            <div className={`border rounded-xl transition-all overflow-hidden ${isHfImportEnabled ? 'border-indigo-200 bg-indigo-50/50' : 'border-gray-200'}`}>
                <button
                    type="button"
                    onClick={() => setIsHfImportEnabled(!isHfImportEnabled)}
                    className="w-full flex items-center justify-between p-4 text-left"
                    disabled={isLoading}
                >
                    <div className="flex items-center gap-2">
                        <Upload className={`w-4 h-4 ${isHfImportEnabled ? 'text-indigo-600' : 'text-gray-500'}`} />
                        <span className={`text-sm font-medium ${isHfImportEnabled ? 'text-indigo-900' : 'text-gray-700'}`}>
                            Import from Hugging Face Space
                        </span>
                    </div>
                    <div className={`w-4 h-4 rounded-full border flex items-center justify-center transition-colors ${isHfImportEnabled ? 'bg-indigo-600 border-indigo-600' : 'border-gray-300'}`}>
                         {isHfImportEnabled && <div className="w-1.5 h-1.5 bg-white rounded-full" />}
                    </div>
                </button>

                {isHfImportEnabled && (
                    <div className="p-4 pt-0 space-y-3 animate-in slide-in-from-top-2">
                        <p className="text-xs text-indigo-700">
                            The space will be uploaded to the selected GitHub repo/branch before the session starts.
                        </p>
                        <div>
                             <label className="block text-xs font-semibold text-indigo-800 mb-1">Hugging Face Space ID</label>
                             <input
                                type="text"
                                value={hfSpaceId}
                                onChange={(e) => setHfSpaceId(e.target.value)}
                                className="w-full px-3 py-2 border border-indigo-200 rounded-lg focus:ring-2 focus:ring-indigo-500 outline-none bg-white text-sm"
                                placeholder="e.g. huggingface/transformers-demo"
                                required={isHfImportEnabled}
                                disabled={isLoading}
                             />
                        </div>
                    </div>
                )}
            </div>

            <div className="pt-2">
                <button
                    type="submit"
                    disabled={isLoading || (!repoSearch && !isHfImportEnabled)}
                    className="w-full bg-indigo-600 hover:bg-indigo-700 text-white font-medium py-3 rounded-xl flex items-center justify-center gap-2 transition-transform active:scale-[0.98] disabled:opacity-50 disabled:cursor-not-allowed"
                >
                    {isLoading ? (
                        <>
                           <Loader2 className="w-4 h-4 animate-spin" />
                           {isHfImportEnabled ? 'Importing & Creating...' : 'Creating Session...'}
                        </>
                    ) : (
                        <>
                           Create Session
                           <Play className="w-4 h-4 fill-current" />
                        </>
                    )}
                </button>
                {!repoSearch && !isHfImportEnabled && (
                    <p className="text-xs text-indigo-500 text-center mt-2">Enter a GitHub repo to start.</p>
                )}
            </div>
        </form>
      </div>
    </div>
  );
};