"""
Citation and sourcing utilities to reduce hallucinations.

When presenting grant information, we cite the source data:
- Grant ID and title
- Specific fields (funding_max, deadline, etc.)
- Field source (from grant record or extracted)

This helps users verify information and trust the system.
"""

from typing import Dict, Any, List, Optional
from datetime import datetime


def cite_grant_fact(grant: Dict[str, Any], field: str, value: Any) -> str:
    """
    Create a citation for a fact about a grant.

    Args:
        grant: The grant record dict
        field: Field name (e.g., "funding_max", "close_date")
        value: The value to cite

    Returns:
        Formatted citation like "£50,000 [Source: Grant ID #2315]"
    """
    grant_id = grant.get("id") or grant.get("competition_id") or "unknown"

    # Special formatting for currency
    if field in ("funding_max", "funding_min", "total_pot") and isinstance(value, (int, float)):
        return f"£{value:,.0f} [Source: Grant ID #{grant_id}]"

    # Special formatting for dates
    if field in ("close_date", "open_date", "deadline") and value:
        return f"{value} [Source: Grant ID #{grant_id}]"

    # Default formatting
    if value is None:
        return "Not specified"

    return f"{value} [Source: Grant ID #{grant_id}]"


def format_grant_with_citations(grant: Dict[str, Any]) -> Dict[str, Any]:
    """
    Format a grant record with citations on key fields.

    Args:
        grant: The grant record

    Returns:
        Dict with cited versions of key fields
    """
    grant_id = grant.get("id") or grant.get("competition_id") or "unknown"
    title = grant.get("title", "(untitled)")

    cited = {
        "id": grant_id,
        "title": title,
        "url": grant.get("url", ""),
    }

    # Cite monetary fields
    if grant.get("funding_max"):
        cited["funding_max"] = cite_grant_fact(grant, "funding_max", grant["funding_max"])
    if grant.get("funding_min"):
        cited["funding_min"] = cite_grant_fact(grant, "funding_min", grant["funding_min"])
    if grant.get("total_pot"):
        cited["total_pot"] = cite_grant_fact(grant, "total_pot", grant["total_pot"])

    # Cite dates
    if grant.get("close_date"):
        cited["close_date"] = cite_grant_fact(grant, "close_date", grant["close_date"])
    if grant.get("open_date"):
        cited["open_date"] = cite_grant_fact(grant, "open_date", grant["open_date"])

    return cited


def build_citation_summary(grant: Dict[str, Any]) -> str:
    """
    Build a markdown summary of grant with citations.

    Args:
        grant: The grant record

    Returns:
        Markdown formatted summary with citations
    """
    grant_id = grant.get("id") or grant.get("competition_id") or "unknown"
    title = grant.get("title", "(untitled)")
    url = grant.get("url", "")

    lines = [
        f"## {title}",
        f"**Grant ID:** #{grant_id}",
        "",
    ]

    if url:
        lines.append(f"**Official Link:** {url}")
        lines.append("")

    # Funding details with citations
    if grant.get("funding_max") or grant.get("funding_min"):
        min_fund = grant.get("funding_min")
        max_fund = grant.get("funding_max")

        if min_fund and max_fund:
            funding_str = f"£{min_fund:,.0f} – £{max_fund:,.0f}"
        elif max_fund:
            funding_str = f"up to £{max_fund:,.0f}"
        elif min_fund:
            funding_str = f"from £{min_fund:,.0f}"
        else:
            funding_str = "See official page"

        lines.append(f"**Funding per project:** {funding_str} [Source: Grant ID #{grant_id}]")

    if grant.get("total_pot"):
        lines.append(f"**Total available:** £{grant['total_pot']:,.0f} [Source: Grant ID #{grant_id}]")

    lines.append("")

    # Dates with citations
    if grant.get("open_date") or grant.get("close_date"):
        close = grant.get("close_date") or grant.get("deadline")
        if close:
            lines.append(f"**Deadline:** {close} [Source: Grant ID #{grant_id}]")
        if grant.get("open_date"):
            lines.append(f"**Opens:** {grant['open_date']} [Source: Grant ID #{grant_id}]")

    lines.append("")

    # Duration with citation
    if grant.get("duration_min") or grant.get("duration_max"):
        min_dur = grant.get("duration_min")
        max_dur = grant.get("duration_max")

        if min_dur and max_dur:
            duration_str = f"{min_dur}–{max_dur} months"
        elif max_dur:
            duration_str = f"up to {max_dur} months"
        elif min_dur:
            duration_str = f"from {min_dur} months"
        else:
            duration_str = "Variable"

        lines.append(f"**Project duration:** {duration_str} [Source: Grant ID #{grant_id}]")

    return "\n".join(lines)


def validate_fact_availability(grant: Dict[str, Any], fact_type: str) -> bool:
    """
    Check if a fact exists in the grant data before citing it.

    Args:
        grant: The grant record
        fact_type: Type of fact ("funding", "deadline", "duration", "scope", "eligibility")

    Returns:
        True if the fact is available to cite

    Raises assertion/warning if fact is missing
    """
    fact_fields = {
        "funding": ["funding_max", "funding_min", "total_pot"],
        "deadline": ["close_date", "deadline"],
        "duration": ["duration_min", "duration_max"],
        "scope": ["scope", "scope_raw", "sections"],
        "eligibility": ["eligibility", "eligibility_raw"],
    }

    required_fields = fact_fields.get(fact_type, [])

    for field in required_fields:
        if grant.get(field):
            return True

    return False