import React, { useState, useEffect } from 'react';
import SolutionNavigator from '../components/SolutionNavigator';

function CustomPuzzlePage() {
  // Custom puzzle input
  const [customPuzzleText, setCustomPuzzleText] = useState("");
  const [sysContent, setSysContent] = useState("");

  // Results
  const [solutions, setSolutions] = useState([]);
  const [currentSolutionIndex, setCurrentSolutionIndex] = useState(0);
  const [generatedCode, setGeneratedCode] = useState("");
  const [isSolving, setIsSolving] = useState(false);
  const [solutionStatus, setSolutionStatus] = useState(""); // "success", "no_solution", "error"
  const [errorMessage, setErrorMessage] = useState("");

  // UI state
  const [currentStep, setCurrentStep] = useState(1);
  const [expandedSections, setExpandedSections] = useState({
    puzzle: true,
    sysContent: false,
    result: false
  });

  // Load default system content
  useEffect(() => {
    fetch(`/default_sys_content_multi`)
      .then(res => res.json())
      .then(data => {
        if(data.success) {
          setSysContent(data.sysContent);
        }
      })
      .catch(e => console.error(e));
  }, []);

  const handleSolveCustom = () => {
    if(!customPuzzleText.trim()) {
      alert("Please enter a puzzle text");
      return;
    }

    const payload = {
      puzzle: customPuzzleText,
      sys_content: sysContent,
      custom: true
    };

    setIsSolving(true);
    setCurrentStep(3);
    setExpandedSections({puzzle: false, sysContent: false, result: true});
    setSolutions([]);
    setCurrentSolutionIndex(0);
    setSolutionStatus("");
    setErrorMessage("");

    fetch(`/solve_custom`, {
      method: "POST",
      headers: { "Content-Type": "application/json" },
      body: JSON.stringify(payload)
    })
    .then(res => res.json())
    .then(data => {
      if(!data.success) {
        setErrorMessage("Backend error: " + data.error);
        setSolutionStatus("error");
        return;
      }
      
      const result = data.result;
      setGeneratedCode(result.generatedCode || "");
      
      if (result.solutions && result.solutions.length > 0) {
        setSolutions(result.solutions);
        setSolutionStatus("success");
        setCurrentSolutionIndex(0);
      } else if (result.no_solution) {
        setSolutionStatus("no_solution");
        setErrorMessage(result.message || "No solution found for this puzzle");
      } else {
        setSolutionStatus("error");
        setErrorMessage(result.error || "Unknown error occurred");
      }
    })
    .catch(e => {
      console.error(e);
      setErrorMessage("Network error: " + e.message);
      setSolutionStatus("error");
    })
    .finally(() => {
      setIsSolving(false);
    });
  };

  const toggleSection = (section) => {
    setExpandedSections({
      ...expandedSections,
      [section]: !expandedSections[section]
    });
  };

  const nextStep = () => {
    if (currentStep < 3) {
      setCurrentStep(currentStep + 1);
      if (currentStep === 1) {
        setExpandedSections({puzzle: false, sysContent: true, result: false});
      } else if (currentStep === 2) {
        setExpandedSections({puzzle: false, sysContent: false, result: true});
      }
    }
  };

  const prevStep = () => {
    if (currentStep > 1) {
      setCurrentStep(currentStep - 1);
      if (currentStep === 2) {
        setExpandedSections({puzzle: true, sysContent: false, result: false});
      } else if (currentStep === 3) {
        setExpandedSections({puzzle: false, sysContent: true, result: false});
      }
    }
  };

  return (
    <>
      {/* Progress Steps */}
      <div className="progress-container">
        <div className="progress-steps">
          <div className={`step ${currentStep >= 1 ? 'active' : ''}`}>
            <div className="step-number">1</div>
            <div className="step-label">Create Puzzle</div>
          </div>
          <div className={`step ${currentStep >= 2 ? 'active' : ''}`}>
            <div className="step-number">2</div>
            <div className="step-label">Configure System</div>
          </div>
          <div className={`step ${currentStep >= 3 ? 'active' : ''}`}>
            <div className="step-number">3</div>
            <div className="step-label">Solve & Results</div>
          </div>
        </div>
      </div>

      <main className="main-content">
        {/* Step 1: Custom Puzzle Input */}
        <section className={`content-section ${expandedSections.puzzle ? 'expanded' : 'collapsed'}`}>
          <div className="section-header" onClick={() => toggleSection('puzzle')}>
            <h2>✏️ Custom Puzzle Creation</h2>
            <span className="toggle-icon">{expandedSections.puzzle ? '▼' : '▶'}</span>
          </div>
          
          {expandedSections.puzzle && (
            <div className="section-content">
              <div className="custom-puzzle-editor">
                <h3>📝 Puzzle Description</h3>
                <p className="description">
                  Enter your custom zebra puzzle. Include categories, items, and constraints:
                </p>
                <div className="puzzle-input-container">
                  <textarea
                    value={customPuzzleText}
                    onChange={(e) => setCustomPuzzleText(e.target.value)}
                    className="custom-puzzle-textarea"
                    placeholder="Example:
There are 5 houses in a row.

Categories:
- Color: red, blue, green, yellow, white
- Name: Alice, Bob, Carol, Dave, Eve
- Pet: cat, dog, fish, bird, rabbit
- Drink: tea, coffee, milk, juice, water
- Sport: tennis, soccer, golf, swimming, running

Constraints:
1. The person in the red house owns a cat.
2. Alice drinks tea.
3. The green house is to the left of the white house.
..."
                  />
                </div>
                
                <div className="puzzle-examples">
                  <h4>💡 Tips for Creating Puzzles:</h4>
                  <ul>
                    <li>Clearly define all categories and their possible values</li>
                    <li>Number your constraints for clarity</li>
                    <li>Use spatial relationships like "to the left of", "next to", "between"</li>
                    <li>Include direct assignments like "Alice lives in the red house"</li>
                    <li>It will be better to have your expected results</li>
                  </ul>
                </div>
              </div>
            </div>
          )}
        </section>

        {/* Step 2: System Configuration */}
        <section className={`content-section ${expandedSections.sysContent ? 'expanded' : 'collapsed'}`}>
          <div className="section-header" onClick={() => toggleSection('sysContent')}>
            <h2>⚙️ System Configuration</h2>
            <span className="toggle-icon">{expandedSections.sysContent ? '▼' : '▶'}</span>
          </div>
          
          {expandedSections.sysContent && (
            <div className="section-content">
              <div className="sys-content-editor">
                <h3>📝 System Content</h3>
                <p className="description">
                  Edit the system prompt that will guide the AI in solving your custom puzzle:
                </p>
                <textarea
                  value={sysContent}
                  onChange={(e) => setSysContent(e.target.value)}
                  className="sys-content-textarea"
                  placeholder="Enter system content..."
                />
              </div>
            </div>
          )}
        </section>

        {/* Step 3: Solve & Results */}
        <section className={`content-section ${expandedSections.result ? 'expanded' : 'collapsed'}`}>
          <div className="section-header" onClick={() => toggleSection('result')}>
            <h2>🚀 Solve & Results</h2>
            <span className="toggle-icon">{expandedSections.result ? '▼' : '▶'}</span>
          </div>
          
          {expandedSections.result && (
            <div className="section-content">
              <div className="solve-section">
                <button 
                  onClick={handleSolveCustom} 
                  disabled={isSolving || !customPuzzleText.trim()}
                  className={`btn btn-primary solve-btn ${isSolving ? 'loading' : ''}`}
                >
                  {isSolving ? '🔄 Solving Custom Puzzle...' : '🧠 Solve Custom Puzzle'}
                </button>
              </div>

              <div className="results-section">
                <div className="result-summary">
                  <div className="result-item">
                    <span className="result-label">Status:</span>
                    <span className={`result-value ${
                      solutionStatus === 'success' ? 'success' : 
                      solutionStatus === 'no_solution' ? 'warning' : 
                      solutionStatus === 'error' ? 'error' : 'pending'
                    }`}>
                      {solutionStatus === 'success' ? "✅ Solved" : 
                       solutionStatus === 'no_solution' ? "⚠️ No Solution" :
                       solutionStatus === 'error' ? "❌ Error" : "⏳ Pending"}
                    </span>
                  </div>
                  {solutions.length > 0 && (
                    <div className="result-item">
                      <span className="result-label">Solutions Found:</span>
                      <span className="result-value">{solutions.length}</span>
                    </div>
                  )}
                </div>

                {/* Solution Navigator */}
                {solutions.length > 0 && (
                  <SolutionNavigator
                    solutions={solutions}
                    currentIndex={currentSolutionIndex}
                    onIndexChange={setCurrentSolutionIndex}
                  />
                )}

                {/* Error Message */}
                {(solutionStatus === 'error' || solutionStatus === 'no_solution') && errorMessage && (
                  <div className="error-section">
                    <h3>⚠️ {solutionStatus === 'no_solution' ? 'No Solution Found' : 'Error'}</h3>
                    <div className="error-display">
                      <pre>{errorMessage}</pre>
                    </div>
                  </div>
                )}

                {/* Generated Code */}
                {generatedCode && (
                  <div className="code-section">
                    <h3>💻 Generated Code</h3>
                    <div className="code-display">
                      <pre><code>{generatedCode}</code></pre>
                    </div>
                  </div>
                )}
              </div>
            </div>
          )}
        </section>
      </main>

      {/* Navigation */}
      <nav className="navigation">
        <button 
          onClick={prevStep} 
          disabled={currentStep <= 1}
          className="btn btn-outline"
        >
          ← Previous
        </button>
        <span className="step-indicator">
          Step {currentStep} of 3
        </span>
        <button 
          onClick={nextStep} 
          disabled={currentStep >= 3}
          className="btn btn-outline"
        >
          Next →
        </button>
      </nav>
    </>
  );
}

export default CustomPuzzlePage;