package logic

import (
	"math/rand"
	"wuziqi-server/core"
)

// GenerateGrid 创建一个新的随机网格
func GenerateGrid(gridSize int, bombCount int, itemMin int, itemMax int, enabledItems map[string]bool, itemWeights map[string]int, allItemTypes []string) []*core.GridCell {
	totalCells := gridSize * gridSize
	grid := make([]*core.GridCell, totalCells)
	for i := 0; i < totalCells; i++ {
		grid[i] = &core.GridCell{Type: "empty", Revealed: false}
	}

	// 放置炸弹
	bombsPlaced := 0
	for bombsPlaced < bombCount && bombsPlaced < totalCells {
		idx := rand.Intn(totalCells)
		if grid[idx].Type == "empty" {
			grid[idx].Type = "bomb"
			bombsPlaced++
		}
	}

	// 过滤启用的道具
	var pool []string
	if len(enabledItems) > 0 {
		for _, it := range allItemTypes {
			if enabled, ok := enabledItems[it]; ok && enabled {
				weight := 10
				if w, ok := itemWeights[it]; ok && w > 0 {
					weight = w
				}
				for i := 0; i < weight; i++ {
					pool = append(pool, it)
				}
			}
		}
	}
	if len(pool) == 0 {
		pool = allItemTypes
	}

	// 放置道具
	itemCount := rand.Intn(itemMax-itemMin+1) + itemMin
	itemsPlaced := 0
	for itemsPlaced < itemCount && (bombsPlaced+itemsPlaced) < totalCells {
		idx := rand.Intn(totalCells)
		if grid[idx].Type == "empty" {
			grid[idx].Type = "item"
			grid[idx].ItemID = pool[rand.Intn(len(pool))]
			itemsPlaced++
		}
	}

	// 计算邻居
	for i := 0; i < totalCells; i++ {
		if grid[i].Type == "bomb" {
			continue
		}
		count := 0
		neighbors := GetNeighborIndices(i, gridSize)
		for _, neighborIdx := range neighbors {
			if grid[neighborIdx].Type == "bomb" {
				count++
			}
		}
		grid[i].NeighborBombs = count
	}

	return grid
}

func GetNeighborIndices(index int, gridSize int) []int {
	neighbors := []int{}
	row := index / gridSize
	col := index % gridSize

	for r := row - 1; r <= row+1; r++ {
		for c := col - 1; c <= col+1; c++ {
			if (r == row && c == col) || r < 0 || r >= gridSize || c < 0 || c >= gridSize {
				continue
			}
			neighbors = append(neighbors, r*gridSize+c)
		}
	}
	return neighbors
}

// RevealSafeArea 使用泛洪填充算法揭示连续的空位
// 标准扫雷规则：揭示边界的数字格子，但不从它们继续扩展
// 道具和炸弹都不会被揭示，它们阻断泛洪填充
func RevealSafeArea(state *core.GameState, startIndex int) []int {
	revealed := []int{}
	visited := make(map[int]bool)

	// 起始格子可能已经被揭示（在调用前被设置），
	// 我们需要从它的邻居开始扩展
	startCell := state.Grid[startIndex]
	visited[startIndex] = true

	// 初始化队列
	var queue []int
	if startCell.NeighborBombs == 0 {
		// 起始格子是空白格（无数字），从邻居开始扩展
		queue = GetNeighborIndices(startIndex, state.GridSize)
	}
	// 如果起始格子有数字，不扩展邻居

	for len(queue) > 0 {
		idx := queue[0]
		queue = queue[1:]

		if visited[idx] {
			continue
		}
		visited[idx] = true

		cell := state.Grid[idx]
		// 如果已揭示、是炸弹或道具则跳过（道具和炸弹阻断泛洪填充）
		if cell.Revealed || cell.Type == "bomb" || cell.Type == "item" {
			continue
		}

		// 揭示空格子（包括有数字的边界格子）
		cell.Revealed = true
		revealed = append(revealed, idx)

		// 只有无炸弹邻居的空位才继续扩展
		if cell.NeighborBombs == 0 {
			neighbors := GetNeighborIndices(idx, state.GridSize)
			queue = append(queue, neighbors...)
		}
	}
	return revealed
}