import type { FileEntry } from "./types";
import { BOLD, GREEN, YELLOW, CYAN, DIM, RESET } from "./terminal";

const UP = "\x1b[A";
const DOWN = "\x1b[B";
const SPACE = " ";
const ENTER = "\r";
const CTRL_C = "\x03";

function hideCursor() {
  process.stdout.write("\x1b[?25l");
}

function showCursor() {
  process.stdout.write("\x1b[?25h");
}

function moveUp(n: number) {
  process.stdout.write(`\x1b[${n}A`);
}

function moveDown(n: number) {
  process.stdout.write(`\x1b[${n}B`);
}

function clearLine() {
  process.stdout.write("\x1b[2K\r");
}

interface SelectItem {
  label: string;
  path: string;
  selected: boolean;
}

export async function selectFiles(
  stagedFiles: FileEntry[],
  unstagedFiles: FileEntry[],
): Promise<string[]> {
  if (unstagedFiles.length === 0) return [];

  if (stagedFiles.length > 0) {
    process.stdout.write(`\n  ${BOLD}Staged files (will be included):${RESET}\n`);
    for (const f of stagedFiles) {
      process.stdout.write(`    ${GREEN}✓${RESET} ${f.path} (${YELLOW}${f.label}${RESET})\n`);
    }
  }

  const items: SelectItem[] = [
    { label: "Select all", path: "__all__", selected: false },
    ...unstagedFiles.map((f) => ({
      label: `${f.path} (${f.label})`,
      path: f.path,
      selected: false,
    })),
  ];

  let cursor = 0;

  process.stdout.write(`\n  ${BOLD}Select files to stage:${RESET}\n`);
  process.stdout.write(`  ${DIM}↑/↓ navigate, space select, enter confirm${RESET}\n\n`);

  const itemStartRow = 4 + (stagedFiles.length > 0 ? stagedFiles.length + 2 : 0);

  function render() {
    for (let i = 0; i < items.length; i++) {
      process.stdout.write("\x1b[2K\r");
      const item = items[i]!;
      const isAll = i === 0;
      const cursor_ = i === cursor ? `${CYAN}❯${RESET} ` : "  ";
      const checkbox = item.selected ? `${GREEN}◉${RESET}` : `${DIM}○${RESET}`;

      if (isAll) {
        process.stdout.write(`${cursor_} ${checkbox} ${BOLD}${item.label}${RESET}\n`);
      } else {
        process.stdout.write(`${cursor_} ${checkbox} ${item.path.includes("(") ? item.label : `${item.label}`}\n`);
      }
    }
    moveUp(items.length);
  }

  function toggleItem(index: number) {
    const item = items[index]!;
    item.selected = !item.selected;

    if (index === 0) {
      for (let i = 1; i < items.length; i++) {
        items[i]!.selected = item.selected;
      }
    } else {
      const allSelected = items.slice(1).every((it) => it.selected);
      items[0]!.selected = allSelected;
    }
  }

  return new Promise((resolve) => {
    if (process.stdin.isTTY !== true) {
      resolve([]);
      return;
    }

    const wasRaw = process.stdin.isRaw;
    if (wasRaw !== true) {
      process.stdin.setRawMode(true);
    }
    process.stdin.resume();
    hideCursor();

    render();

    const onData = (data: Buffer) => {
      const key = data.toString();

      if (key === CTRL_C) {
        process.stdin.setRawMode(wasRaw === true);
        process.stdin.pause();
        process.stdin.removeListener("data", onData);
        showCursor();
        for (let i = 0; i < items.length; i++) {
          process.stdout.write("\x1b[2K\n");
        }
        moveUp(items.length);
        process.stdout.write(`\n  Aborted.\n`);
        process.exit(1);
      }

      if (key === UP) {
        if (cursor > 0) {
          cursor--;
          render();
        }
      } else if (key === DOWN) {
        if (cursor < items.length - 1) {
          cursor++;
          render();
        }
      } else if (key === SPACE) {
        toggleItem(cursor);
        render();
      } else if (key === ENTER) {
        process.stdin.setRawMode(wasRaw === true);
        process.stdin.pause();
        process.stdin.removeListener("data", onData);

        for (let i = 0; i < items.length; i++) {
          process.stdout.write("\x1b[2K\n");
        }
        moveUp(items.length);

        const selected = items
          .slice(1)
          .filter((it) => it.selected)
          .map((it) => it.path);

        if (selected.length > 0) {
          process.stdout.write(
            `  ${GREEN}Staged ${selected.length} file(s):${RESET} ${selected.join(", ")}\n`,
          );
        }

        showCursor();
        resolve(selected);
      }
    };

    process.stdin.on("data", onData);
  });
}