import os
import boto3
from botocore.exceptions import ClientError

# Cache keyed by actor_id ('' = global/no user)
_prompt_cache: dict[str, str] = {}


def build_system_prompt(user_context: str = '', actor_id: str = '') -> str:
    """Build system prompt from S3 workspace files + optional per-user context."""
    base = _get_base_prompt(actor_id)
    if user_context:
        return base + f'\n\n---\n\n## User\n{user_context}'
    return base


def _get_base_prompt(actor_id: str = '') -> str:
    if actor_id in _prompt_cache:
        return _prompt_cache[actor_id]

    bucket = os.environ.get('WORKSPACE_BUCKET_NAME', '') or 'agent-claw-workspace-495395224548'
    print(f'[prompt_builder] Loading from bucket: {bucket!r} actor_id={actor_id!r}')

    if not bucket:
        print('[prompt_builder] WARNING: WORKSPACE_BUCKET_NAME not set!')
        _prompt_cache[actor_id] = 'You are a helpful personal assistant.'
        return _prompt_cache[actor_id]

    s3 = boto3.client('s3')
    parts = []

    # Per-user MEMORY.md (falls back to global)
    memory_key = f'users/{actor_id}/MEMORY.md' if actor_id else 'MEMORY.md'
    try:
        obj = s3.get_object(Bucket=bucket, Key=memory_key)
        content = obj['Body'].read().decode('utf-8')
        parts.append(f'## MEMORY.md\n{content}')
        print(f'[prompt_builder] Loaded {memory_key} ({len(content)} bytes)')
    except ClientError as e:
        if e.response['Error']['Code'] in ('NoSuchKey', 'AccessDenied') and actor_id:
            # Fall back to global MEMORY.md
            try:
                obj = s3.get_object(Bucket=bucket, Key='MEMORY.md')
                content = obj['Body'].read().decode('utf-8')
                parts.append(f'## MEMORY.md\n{content}')
                print(f'[prompt_builder] Loaded MEMORY.md (fallback, {len(content)} bytes)')
            except Exception as e2:
                print(f'[prompt_builder] Failed to load MEMORY.md: {e2}')
        else:
            print(f'[prompt_builder] Failed to load {memory_key}: {e}')

    for fname in ['SOUL.md', 'AGENTS.md', 'IDENTITY.md', 'TOOLS.md', 'HEARTBEAT.md']:
        try:
            obj = s3.get_object(Bucket=bucket, Key=fname)
            content = obj['Body'].read().decode('utf-8')
            parts.append(f'## {fname}\n{content}')
            print(f'[prompt_builder] Loaded {fname} ({len(content)} bytes)')
        except Exception as e:
            print(f'[prompt_builder] Failed to load {fname}: {e}')

    parts.append('## Runtime\nRuntime: agent-claw | host=AgentCore | model=bedrock-claude-sonnet | channel=telegram\nCurrent date/time is provided by the system. Timezone: America/Chicago.')

    result = '\n\n---\n\n'.join(parts)
    _prompt_cache[actor_id] = result
    print(f'[prompt_builder] Prompt built for actor_id={actor_id!r}: {len(result)} chars')
    return result


def invalidate_prompt(actor_id: str = '') -> None:
    """Invalidate cached prompt for a specific actor_id, or all if not specified."""
    if actor_id:
        _prompt_cache.pop(actor_id, None)
    else:
        _prompt_cache.clear()