let height    = 10
let width     = 10
let mine_rate = 0.10
let timer     = undefined

let mines = []
let visited = []

let running = false

function isValidPos(y, x) {
    return y >= 0 && y < height && x >= 0 && x < width
}

function* neighboursGenerator(y, x) {
    for (let i = -1; i <= 1; i++) {
        for (let j = -1; j <= 1; j++) {
            if (i === 0 && j === 0)
                continue
            let ret = [y + i, x + j]
            if (!isValidPos(...ret))
                continue
            yield ret
        }
    }
}

let cells = []

function floodFill(y, x) {
    visited[y][x] = true
    let cell = cells[y][x]
    cell.classList.add("visited")
    if (mines[y][x] !== 0)
        cell.textContent = mines[y][x]
    switch (mines[y][x]) {
        case 1: cell.style.color = "blue";     break
        case 2: cell.style.color = "green";    break
        case 3: cell.style.color = "red";      break
        case 4: cell.style.color = "darkblue"; break
        case 5: cell.style.color = "brown";    break
        case 6: cell.style.color = "cyan";     break
        case 7: cell.style.color = "black";    break
        case 8: cell.style.color = "grey";     break
    }
    if (mines[y][x] !== 0)
        return
    for (let [ny, nx] of neighboursGenerator(y, x))
        if (!visited[ny][nx])
            floodFill(ny, nx)
}

function initGrid() {
    let table = document.getElementById("minesweeper-table")
    table.innerHTML = ""

    width     = document.getElementById("minesweeper-width").value
    height    = document.getElementById("minesweeper-height").value
    mine_rate = document.getElementById("minesweeper-mine-rate").value / 100

    mines   = []
    visited = []
    cells   = []

    for (let i = 0; i < height; i++) {
        mines.push(new Array(width))
        visited.push(new Array(width))
        for (let j = 0; j < width; j++) {
            mines[i][j] = Math.random() < mine_rate ? -1 : 0;
            visited[i][j] = false;
        }
    }

    // count neighbour mines
    for (let i = 0; i < height; i++) {
        for (let j = 0; j < width; j++) {
            if (mines[i][j] === -1)
                continue
            mines[i][j] =
                [...neighboursGenerator(i, j)]
                .filter(([y, x]) => mines[y][x] === -1)
                .length
        }
    }

    for (let i = 0; i < height; i++) {
        cells.push([])
        let table_row = document.createElement("tr")
        for (let j = 0; j < width; j++) {
            let table_cell = document.createElement("td")
            let cell = document.createElement("button")
            cell.textContent = ""
            cell.addEventListener("click", () => floodFill(i, j))
            cells[i].push(cell)
            table_cell.appendChild(cell)
            table_row.appendChild(table_cell)
        }
        table.appendChild(table_row)
    }
}

for (input of document.querySelectorAll("#minesweeper-settings input")) {
    input.addEventListener("input", () => initGrid())
}

function toggleRunning() {
    running         = !running
    settings        = document.getElementById("minesweeper-settings")
    info            = document.getElementById("minesweeper-game-info")
    settings.hidden = !settings.hidden
    info.hidden     = !info.hidden
    // if (timer === undefined) {
    // }
}

document.getElementById("minesweeper-start").addEventListener("click", toggleRunning)
document.getElementById("minesweeper-stop") .addEventListener("click", toggleRunning)

initGrid()