"""AI-generated narrative commentary for financial reports.

Takes a report_result dict + optional anomalies list, builds an LLM
prompt, parses the structured output. Output contract:
{
  'summary': str,            # 2-3 sentence executive summary
  'highlights': [str, ...],  # 3-5 bullet observations
  'concerns': [str, ...],    # things that warrant investigation
  'next_actions': [str, ...] # suggested follow-ups
}
"""

import json
import logging

_logger = logging.getLogger(__name__)


def generate_commentary(env, *, report_result: dict, anomalies: list = None,
                        provider=None) -> dict:
    """Generate narrative commentary via LLM. Returns dict per the contract.

    If no provider configured, returns a templated fallback (no LLM)."""
    if provider is None:
        provider = _get_provider(env)
    if provider is None:
        return _templated_fallback(report_result, anomalies)

    try:
        from odoo.addons.fusion_accounting_reports.services.commentary_prompt import build_prompt
    except ImportError:
        _logger.debug("commentary_prompt module not yet available; using fallback")
        return _templated_fallback(report_result, anomalies)

    system, user = build_prompt(report_result, anomalies or [])
    try:
        response = provider.complete(
            system=system,
            messages=[{'role': 'user', 'content': user}],
            max_tokens=1200,
            temperature=0.2,
        )
        content = response.get('content') if isinstance(response, dict) else response
        parsed = json.loads(content)
        # Validate shape
        for key in ('summary', 'highlights', 'concerns', 'next_actions'):
            parsed.setdefault(key, [] if key != 'summary' else '')
        return parsed
    except Exception as e:
        _logger.warning("AI commentary generation failed: %s", e)
        return _templated_fallback(report_result, anomalies)


def _templated_fallback(report_result: dict, anomalies: list = None) -> dict:
    """No-LLM fallback that produces a basic narrative from the report data."""
    anomalies = anomalies or []
    rows = report_result.get('rows', [])
    period = report_result.get('period', {})
    period_label = period.get('label', 'this period')

    # Find subtotal rows for the summary
    subtotals = [r for r in rows if r.get('is_subtotal')]
    summary_parts = [f"{report_result.get('report_name', 'Report')} for {period_label}."]
    if subtotals:
        last = subtotals[-1]
        summary_parts.append(f"{last['label']}: ${last['amount']:,.2f}.")

    highlights = []
    for row in subtotals[:3]:
        highlights.append(f"{row['label']}: ${row['amount']:,.2f}")

    concerns = []
    for a in anomalies[:3]:
        concerns.append(
            f"{a['label']} {a['direction']}d {a['variance_pct']:.1f}% "
            f"(${a['variance_amount']:+,.2f})")

    return {
        'summary': ' '.join(summary_parts),
        'highlights': highlights,
        'concerns': concerns,
        'next_actions': ['Review the flagged anomalies above.'] if concerns else [],
    }


def _get_provider(env):
    """Look up provider for 'reports_commentary' feature; return None if not configured."""
    param = env['ir.config_parameter'].sudo()
    provider_name = param.get_param('fusion_accounting.provider.reports_commentary')
    if not provider_name:
        provider_name = param.get_param('fusion_accounting.provider.default')
    if not provider_name:
        return None
    try:
        from odoo.addons.fusion_accounting_ai.services.adapters.openai_adapter import OpenAIAdapter
        from odoo.addons.fusion_accounting_ai.services.adapters.claude import ClaudeAdapter
    except ImportError:
        return None
    if provider_name.startswith('openai'):
        return OpenAIAdapter(env)
    elif provider_name.startswith('claude'):
        return ClaudeAdapter(env)
    return None