//
//  PuzzleGenerator.swift
//  AIGrammar
//
//  Created by oscar on 2025/7/21.
//

import Foundation
import SwiftUI

class PuzzleGenerator {
    private(set) var validationWords: Set<String> = []
    private(set) var puzzleWords: [String] = []

    init() {
        //loadValidationWords()
        //loadPuzzleWords()
        validationWords = Set(loadWords(from: "wordlist"))
        puzzleWords = loadWords(from: "puzzle")
    }

    /// 通用加载逻辑
    private func loadWords(from fileName: String) -> [String] {
        if let url = Bundle.main.url(forResource: fileName, withExtension: "txt") {
            do {
                let content = try String(contentsOf: url)
                let words = content
                    .components(separatedBy: .newlines)
                    .map { $0.trimmingCharacters(in: .whitespacesAndNewlines).uppercased() }
                    .filter { !$0.isEmpty }
                logger.info("Loaded \(words.count) words from \(fileName).txt")
                return words
            } catch {
                logger.warning("Failed to load \(fileName).txt: \(error)")
            }
        } else {
            logger.warning("\(fileName).txt not found!")
        }
        return []
    }
    
    /// 加载验证单词库
    private func loadValidationWords() {
        if let url = Bundle.main.url(forResource: "wordlist", withExtension: "txt") {
            do {
                let content = try String(contentsOf: url)
                validationWords = Set(content
                    .components(separatedBy: .newlines)
                    .map { $0.trimmingCharacters(in: .whitespacesAndNewlines).uppercased() }
                    .filter { !$0.isEmpty })
                logger.info("Loaded validation words: \(validationWords.count)")
            } catch {
                logger.warning("Failed to load wordlist.txt: \(error)")
            }
        }
    }

    /// 加载出题单词库
    private func loadPuzzleWords() {
        if let url = Bundle.main.url(forResource: "puzzle", withExtension: "txt") {
            do {
                let content = try String(contentsOf: url)
                puzzleWords = content
                    .components(separatedBy: .newlines)
                    .map { $0.trimmingCharacters(in: .whitespacesAndNewlines).uppercased() }
                    .filter { !$0.isEmpty }
                logger.info("Loaded puzzle words: \(puzzleWords.count)")
            } catch {
                logger.warning("Failed to load puzzle.txt: \(error)")
            }
        }
    }

    /// 随机生成一套题目
    func generatePuzzle() -> (Set<String>, [[String]]) {
        var chosenWords: Set<String> = []
        var uniqueLetters: Set<Character> = []

        while (uniqueLetters.count < 16 && chosenWords.count < 6) || chosenWords.count < 4 {
            if let word = puzzleWords.randomElement() {
                chosenWords.insert(word)
                uniqueLetters.formUnion(word)
            }
        }

        // 保证16个不同字母
        var selectedLetters = Array(uniqueLetters)
        let alphabet = Array("ABCDEFGHIJKLMNOPQRSTUVWXYZ")
        while selectedLetters.count < 16 {
            let randomLetter = alphabet.randomElement()!
            if !selectedLetters.contains(randomLetter) {
                selectedLetters.append(randomLetter)
            }
        }

        let shuffledLetters = selectedLetters.shuffled()

        var letters: [[String]] = Array(repeating: Array(repeating: "", count: 4), count: 4)
        for i in 0..<4 {
            for j in 0..<4 {
                letters[i][j] = String(shuffledLetters[i * 4 + j])
            }
        }

        return (chosenWords, letters)
    }

    /// 校验用户提交的单词
    func validate(word: String) -> Bool {
        validationWords.contains(word.uppercased())
    }
}