"""Jira Cloud as a todo source.

Auth is HTTP Basic with an Atlassian account email + API token, and search goes
through the token-paginated `/rest/api/3/search/jql` endpoint — both carried
over from jira-helper's client. The difference is the query: jira-helper asks
"what is due today", this asks "what is open at all", because you need
something to start a pomodoro on even when nothing is due.

Nothing is written back: you close an issue in Jira, and the next refresh
notices it has left the "open issues" query. One owner per task.
"""

from __future__ import annotations

import re
from collections.abc import Iterator
from datetime import date
from typing import Any

import httpx

from app.settings_schema import JiraSourceSettings
from app.sources.base import SourceError, TodoItem

_SEARCH_PATH = "/rest/api/3/search/jql"
_BASE_FIELDS = ["summary", "duedate", "status", "assignee", "priority", "project", "labels"]
_OPEN_CONDITION = "statusCategory != Done"
_CUSTOM_FIELD_RE = re.compile(r"^customfield_(\d+)$")


def start_date_clause(field_id: str) -> str:
    """`customfield_10015` has to be written `cf[10015]` in JQL; names get quoted."""
    match = _CUSTOM_FIELD_RE.match(field_id)
    return f"cf[{match.group(1)}]" if match else f'"{field_id}"'


class JiraSource:
    name = "jira"

    def __init__(self, config: JiraSourceSettings, *, timeout: int = 30) -> None:
        if not (config.base_url and config.email and config.api_token):
            raise SourceError("Jira needs a base URL, an account email and an API token.")
        self._config = config
        self._base_url = config.base_url.rstrip("/")
        self._client = httpx.Client(
            base_url=self._base_url,
            auth=(config.email, config.api_token),
            headers={"Accept": "application/json", "Content-Type": "application/json"},
            timeout=timeout,
        )

    # ---- plumbing ----------------------------------------------------------

    def _request(self, method: str, path: str, **kwargs: Any) -> Any:
        try:
            resp = self._client.request(method, path, **kwargs)
        except httpx.HTTPError as exc:
            raise SourceError(f"Jira is unreachable: {exc}") from exc
        if resp.status_code in (401, 403):
            raise SourceError(
                "Jira rejected the credentials (check the account email and the "
                "API token — a token, never your password)."
            )
        if not resp.is_success:
            raise SourceError(f"Jira {method} {path} -> {resp.status_code}: {resp.text[:300]}")
        if resp.status_code == 204 or not resp.content:
            return None
        return resp.json()

    def _fields(self) -> list[str]:
        return [*_BASE_FIELDS, self._config.start_date_field]

    def _jql(self) -> str:
        """Open issues, newest deadlines first, narrowed by the user's extra JQL."""
        jql = _OPEN_CONDITION
        if not self._config.include_all_open:
            clause = start_date_clause(self._config.start_date_field)
            jql = (
                f"({_OPEN_CONDITION}) AND "
                f"(duedate <= startOfDay('+7d') OR {clause} <= startOfDay())"
            )
        if self._config.extra_jql.strip():
            jql = f"({jql}) AND ({self._config.extra_jql.strip()})"
        return f"{jql} ORDER BY duedate ASC, priority DESC, updated DESC"

    def _search(self, jql: str) -> Iterator[dict[str, Any]]:
        payload: dict[str, Any] = {
            "jql": jql,
            "maxResults": 100,
            "fields": self._fields(),
        }
        seen = 0
        while True:
            data = self._request("POST", _SEARCH_PATH, json=payload) or {}
            for issue in data.get("issues", []):
                yield issue
                seen += 1
                if seen >= self._config.max_issues:
                    return
            token = data.get("nextPageToken")
            if not token:
                return
            payload["nextPageToken"] = token

    # ---- source API --------------------------------------------------------

    def fetch(self) -> list[TodoItem]:
        return [self._to_item(issue) for issue in self._search(self._jql())]

    def check(self) -> str:
        me = self._request("GET", "/rest/api/3/myself") or {}
        return f"{me.get('displayName', 'unknown')} on {self._base_url}"

    def close(self) -> None:
        self._client.close()

    # ---- mapping -----------------------------------------------------------

    def _to_item(self, issue: dict[str, Any]) -> TodoItem:
        fields = issue.get("fields") or {}
        key = issue.get("key", "")
        status = (fields.get("status") or {}).get("name")
        category = ((fields.get("status") or {}).get("statusCategory") or {}).get("key")
        return TodoItem(
            source=self.name,
            external_id=key,
            title=(fields.get("summary") or "").strip() or key,
            url=f"{self._base_url}/browse/{key}",
            project=((fields.get("project") or {}).get("name")),
            status=status,
            priority=(fields.get("priority") or {}).get("name"),
            due_date=_parse_date(fields.get("duedate")),
            start_date=_parse_date(fields.get(self._config.start_date_field)),
            labels=list(fields.get("labels") or []),
            is_done=category == "done",
            raw={"key": key, "statusCategory": category},
        )


def _parse_date(raw: Any) -> date | None:
    if not raw:
        return None
    try:
        return date.fromisoformat(str(raw)[:10])
    except ValueError:
        return None