from datetime import UTC, date, datetime
from typing import Any

import httpx


class GiteaSourceError(RuntimeError):
    pass


def _parse_gitea_date(raw: Any) -> str | None:
    if isinstance(raw, int):
        return datetime.fromtimestamp(raw, tz=UTC).date().isoformat()
    if isinstance(raw, float):
        return datetime.fromtimestamp(int(raw), tz=UTC).date().isoformat()
    if isinstance(raw, str):
        try:
            if len(raw) == 10 and raw[4] == "-" and raw[7] == "-":
                return raw
            if raw.isdigit():
                return datetime.fromtimestamp(int(raw), tz=UTC).date().isoformat()
            return datetime.fromisoformat(raw.replace("Z", "+00:00")).date().isoformat()
        except ValueError:
            return None
    return None


async def fetch_gitea_activity(
    base_url: str,
    username: str,
    token: str | None,
    from_date: date,
    to_date: date,
    timeout_seconds: float = 20.0,
) -> dict[str, int]:
    endpoint = f"{base_url.rstrip('/')}/api/v1/users/{username}/heatmap"
    headers: dict[str, str] = {"Accept": "application/json"}
    if token:
        headers["Authorization"] = f"token {token}"

    async with httpx.AsyncClient(timeout=timeout_seconds) as client:
        response = await client.get(endpoint, headers=headers)

    if response.status_code >= 400:
        raise GiteaSourceError(f"Gitea heatmap request failed with status {response.status_code}")

    payload = response.json()
    if not isinstance(payload, list):
        raise GiteaSourceError("Unexpected Gitea heatmap payload format")

    normalized: dict[str, int] = {}
    for item in payload:
        if not isinstance(item, dict):
            continue

        date_key = _parse_gitea_date(item.get("date") or item.get("timestamp") or item.get("day"))
        if not date_key:
            continue

        count = item.get("contributions")
        if count is None:
            count = item.get("count", 0)
        try:
            count_int = int(count)
        except (TypeError, ValueError):
            count_int = 0

        if from_date.isoformat() <= date_key <= to_date.isoformat():
            normalized[date_key] = normalized.get(date_key, 0) + count_int

    return normalized