#!/usr/bin/env python3
# description: Write or overwrite a file; must read with file_read first
# Args: <file_path> <content>

import sys
import os
import hashlib
import difflib

def marker_path(file_path):
    h = hashlib.sha256(file_path.encode()).hexdigest()[:64]
    sid = os.environ.get('OLLIE_SESSION_ID', '_')
    return f"/tmp/ollie/{sid}/{h}"

def unified_diff(path, old, new):
    old_lines = old.splitlines(keepends=True)
    new_lines = new.splitlines(keepends=True)
    return ''.join(difflib.unified_diff(old_lines, new_lines, fromfile=path, tofile=path))

if len(sys.argv) < 3:
    print("usage: file_write <file_path> <content>")
    sys.exit(1)

file_path = sys.argv[1]
content   = sys.argv[2]

if not os.path.isabs(file_path):
    print(f"error: path must be absolute, got: {file_path}")
    sys.exit(1)

marker = marker_path(file_path)
if not os.path.exists(marker):
    print(f"error: {file_path} must be read first with file_read")
    sys.exit(1)

exists = os.path.exists(file_path)
old_content = ""
if exists:
    with open(marker, 'r', errors='replace') as f:
        old_content = f.read()

try:
    with open(marker, 'w') as f:
        f.write(content)
    with open(file_path, 'w') as f:
        f.write(content)
except OSError as e:
    print(f"error: {e}")
    sys.exit(1)

os.unlink(marker)

if not exists:
    for line in content.splitlines():
        print(f"+{line}")
else:
    diff = unified_diff(file_path, old_content, content)
    print(diff if diff else "(no changes)", end='' if diff else '\n')