#!/usr/bin/env python3
# ollie:prompt
# ## file_write
#
# Create or overwrite a file. Produces a unified diff.
#
# **Args**: `[path, content]`
#
# ```
# call_tool: calls=[{tool: "file_write", args: ["/abs/path", "file content here"]}]
# ```
#
# **Constraints**: Absolute paths only. Parent directory must exist.
# ollie:end

import sys
import os
import difflib

def format_diff(path, old, new):
    old_lines = old.splitlines(keepends=True)
    new_lines = new.splitlines(keepends=True)
    diff = ''.join(difflib.unified_diff(old_lines, new_lines, fromfile=path, tofile=path))
    if not diff:
        return None
    if not diff.endswith('\n'):
        diff += '\n'
    return f"```diff\n{diff}```"

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"STATUS=error STATE_CHANGED=false RETRYABLE=false")
    print(f"error: path must be absolute, got: {file_path}")
    sys.exit(1)

parent = os.path.dirname(file_path)
if parent and not os.path.isdir(parent):
    print(f"STATUS=error STATE_CHANGED=false RETRYABLE=false")
    print(f"error: parent directory does not exist: {parent}")
    sys.exit(1)

old_content = ""
if os.path.exists(file_path):
    try:
        with open(file_path, 'r', encoding='utf-8') as f:
            old_content = f.read()
    except UnicodeDecodeError:
        with open(file_path, 'r', encoding='utf-8', errors='replace') as f:
            old_content = f.read()

try:
    with open(file_path, 'w', encoding='utf-8') as f:
        f.write(content)
except OSError as e:
    print(f"STATUS=error STATE_CHANGED=false RETRYABLE=false")
    print(f"error: {e}")
    sys.exit(1)

diff = format_diff(file_path, old_content, content)
if diff is None:
    print("STATUS=no_change STATE_CHANGED=false RETRYABLE=false")
    print("(no changes)")
else:
    print("STATUS=done STATE_CHANGED=true")
    print(diff)