import color from "picocolors";
import { initKeypress, onKey, stopKeypress } from "./keyboard.js";

function clearScreen() {
  process.stdout.write('\x1Bc');
}

function strWidth(str) {
  let width = 0;
  for (const char of str) {
    width += char.charCodeAt(0) > 127 ? 2 : 1;
  }
  return width;
}

function padEnd(str, width) {
  return str + " ".repeat(Math.max(0, width - strWidth(str)));
}

export async function gridSelect(options) {
  const {
    items,
    cols = 3,
    colWidth = 24,
    title = "",
    renderHeader = null,
    updateInfo = null,
    headerGap = 2,      // header后的空行数
    menuGap = 2,        // 菜单和提示文字的间隔
    rowGap = 1          // 每行菜单后的空行数
  } = options;

  let current = 0;
  let onUpdate = updateInfo ? true : false; // 如果有更新，默认选中更新按钮
  let resolved = false;
  const rows = Math.ceil(items.length / cols);
  const termWidth = process.stdout.columns || 80;
  const totalWidth = cols * colWidth;
  const pad = " ".repeat(Math.max(0, Math.floor((termWidth - totalWidth) / 2)));

  function render() {
    clearScreen();

    if (renderHeader) {
      console.log(renderHeader(onUpdate));
    }

    for (let i = 0; i < headerGap; i++) console.log("");

    if (title) {
      const titlePad = " ".repeat(Math.max(0, Math.floor((termWidth - title.length - 4) / 2)));
      console.log(titlePad + color.bgMagenta(color.white(` ${title} `)));
    }

    console.log(pad + color.dim("↑ ↓ ← → 选择  |  Enter 确认  |  Esc 退出"));
    for (let i = 0; i < menuGap; i++) console.log("");

    for (let row = 0; row < rows; row++) {
      let line = "";
      let descLine = "";

      for (let col = 0; col < cols; col++) {
        const idx = row * cols + col;
        if (idx < items.length) {
          const item = items[idx];
          if (!onUpdate && idx === current) {
            line += color.cyan("[" + item.name + "]");
          } else {
            line += " " + item.name + " ";
          }
          line += " ".repeat(colWidth - strWidth(item.name) - 2);
          descLine += padEnd(item.desc || "", colWidth);
        }
      }

      console.log(pad + line);
      console.log(pad + color.dim(descLine));
      for (let i = 0; i < rowGap; i++) console.log("");
    }
  }

  return new Promise(resolve => {
    initKeypress();
    render();

    onKey((str, key) => {
      if (!key || resolved) return;

      const row = Math.floor(current / cols);
      const col = current % cols;

      switch (key.name) {
        case "up":
          if (onUpdate) {
            // 已在更新按钮，不能再上
          } else if (row === 0 && updateInfo) {
            onUpdate = true; render();
          } else if (row > 0) {
            current -= cols; render();
          }
          break;
        case "down":
          if (onUpdate) {
            onUpdate = false; render();
          } else if (row < rows - 1 && current + cols < items.length) {
            current += cols; render();
          }
          break;
        case "left":
          if (!onUpdate && col > 0) { current--; render(); }
          break;
        case "right":
          if (!onUpdate && col < cols - 1 && current < items.length - 1) { current++; render(); }
          break;
        case "return":
          resolved = true;
          stopKeypress();
          if (onUpdate) {
            setImmediate(() => resolve({ isUpdate: true }));
          } else {
            setImmediate(() => resolve(items[current]));
          }
          break;
        case "escape":
          resolved = true;
          stopKeypress();
          clearScreen();
          console.log(color.yellow("再见！"));
          process.exit(0);
          break;
        case "c":
          if (key.ctrl) {
            resolved = true;
            stopKeypress();
            clearScreen();
            console.log(color.yellow("再见！"));
            process.exit(0);
          }
          break;
      }
    });
  });
}