#!/usr/bin/env python3
"""Read a file from /workspace with optional line range."""
import json
import os
import sys

args = json.loads(sys.stdin.read())
path = args.get("path", "")
offset = max(int(args.get("offset", 1)), 1)
limit = max(int(args.get("limit", 200)), 1)

WORKSPACE = os.environ.get("WORKSPACE", "/workspace")

# Resolve to absolute and ensure it stays under /workspace
resolved = os.path.realpath(path)
if not resolved.startswith(WORKSPACE + "/") and resolved != WORKSPACE:
    print(f"[error: path must be under {WORKSPACE}]")
    sys.exit(0)

if not os.path.exists(resolved):
    print(f"[error: file not found: {path}]")
    sys.exit(0)

if os.path.isdir(resolved):
    entries = sorted(os.listdir(resolved))
    print(f"Directory listing of {path} ({len(entries)} entries):")
    for entry in entries[:100]:
        full = os.path.join(resolved, entry)
        kind = "dir" if os.path.isdir(full) else "file"
        print(f"  {entry} ({kind})")
    if len(entries) > 100:
        print(f"  ... and {len(entries) - 100} more")
    sys.exit(0)

# Binary detection — check first 512 bytes
try:
    with open(resolved, "rb") as f:
        chunk = f.read(512)
    if b"\x00" in chunk:
        size = os.path.getsize(resolved)
        print(f"[binary file: {path} ({size} bytes)]")
        sys.exit(0)
except Exception as e:
    print(f"[error reading file: {e}]")
    sys.exit(0)

# Read with line range
try:
    with open(resolved) as f:
        lines = f.readlines()
except Exception as e:
    print(f"[error reading file: {e}]")
    sys.exit(0)

total = len(lines)
start_idx = offset - 1  # 0-based
end_idx = min(start_idx + limit, total)

if start_idx >= total:
    print(f"[file has {total} lines — offset {offset} is beyond end of file]")
    sys.exit(0)

for i in range(start_idx, end_idx):
    print(f"{i + 1}\t{lines[i]}", end="")

if end_idx < total:
    print(f"\n[showing lines {offset}-{end_idx} of {total} — use offset={end_idx + 1} to read more]")