// frontend/src/App.js
import React, { useState, useEffect } from 'react';

function App() {
  // For puzzle index and puzzle data
  const [puzzleIndex, setPuzzleIndex] = useState(0);
  const [puzzleText, setPuzzleText] = useState("");
  const [expectedSolution, setExpectedSolution] = useState(null);

  // sysContent can be editted, default using Example.txt
  const [sysContent, setSysContent] = useState("");

  // Interaction results
  const [generatedCode, setGeneratedCode] = useState("");
  const [executionSuccess, setExecutionSuccess] = useState(null);
  const [attempts, setAttempts] = useState(0);
  const [isSolving, setIsSolving] = useState(false);
  const [problematicConstraints, setProblematicConstraints] = useState("");

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

  // When puzzleIndex changing，auto get puzzle
  useEffect(() => {
    fetch(`/get_puzzle?index=${puzzleIndex}`)
      .then(res => res.json())
      .then(data => {
        if(data.success) {
          setPuzzleText(data.puzzle);
          setExpectedSolution(data.expected_solution);
        } else {
          console.error("Failed to fetch puzzle", data.error);
          setPuzzleText("");
          setExpectedSolution(null);
        }
      })
      .catch(e => console.error(e));
  }, [puzzleIndex]);

  const handleSolve = () => {
    if(!puzzleText || !expectedSolution) {
      alert("puzzle or expectedSolution incomplete");
      return;
    }
    const payload = {
      index: puzzleIndex,
      puzzle: puzzleText,
      expected_solution: expectedSolution,
      sys_content: sysContent,
      problematic_constraints: problematicConstraints
    };

    setIsSolving(true);

    fetch(`/solve`, {
      method: "POST",
      headers: { "Content-Type": "application/json" },
      body: JSON.stringify(payload)
    })
    .then(res => res.json())
    .then(data => {
      if(!data.success) {
        alert("Backend error: " + data.error);
        return;
      }
      const result = data.result;
      setGeneratedCode(result.generatedCode || "");
      setExecutionSuccess(result.success);
      setAttempts(result.attempts || 0);
      setProblematicConstraints(result.problematicConstraints || "");
    })
    .catch(e => console.error(e))
    .finally(() => {
      setIsSolving(false);
    });
  };

  return (
    <div style={{ margin: 20 }}>
      <h1>Zebra Puzzle Demo</h1>

      <div style={{ marginBottom: 20 }}>
        <label>Choose puzzle index (0 - 999): </label>
        <input
          type="number"
          value={puzzleIndex}
          onChange={(e) => setPuzzleIndex(Number(e.target.value))}
          min={0}
          max={999}
        />
        <button onClick={() => setPuzzleIndex(puzzleIndex)}>Load Puzzle</button>
      </div>

      <div style={{ marginBottom: 20 }}>
        <h3>Puzzle Text</h3>
        <pre>{puzzleText}</pre>
        <h3>Expected Solution</h3>
        <pre>{JSON.stringify(expectedSolution, null, 2)}</pre>
      </div>

      <div style={{ marginBottom: 20 }}>
        <h3>sys_content</h3>
        <textarea
          rows={10}
          cols={80}
          value={sysContent}
          onChange={(e) => setSysContent(e.target.value)}
        />
      </div>

      <div style={{ marginBottom: 20 }}>
        <button onClick={handleSolve} disabled={isSolving}>Solve Puzzle with LLM</button>
      </div>

      <div>
        <h2>Result</h2>
        <p>Success: {executionSuccess === null ? "N/A" : executionSuccess ? "✅" : "❌"}</p>
        <p>Attempts: {attempts}</p>
        <h3>Issues</h3>
        <pre>{problematicConstraints}</pre>
        <h3>Generated Code</h3>
        <pre>{generatedCode}</pre>
      </div>
    </div>
  );
}

export default App;