"""SourceCraft REST API client (ARCHITECTURE §2.4). The API drops TLS connections now and then: every call retries.

Runs don't carry a commit sha, so the uploads CI prints it from its first cube (`check/meta`, ADR-014);
`run_commit_sha` reads it back.
"""

import asyncio
import logging
import re
from collections.abc import Awaitable, Callable
from types import TracebackType
from typing import Any, Self

import httpx

from app.config import SourceCraftSettings
from app.sourcecraft.models import CubeLog, Run

log = logging.getLogger(__name__)

META_TASK = "check"
META_CUBE = "meta"
_SHA_LINE = re.compile(r"^TGIT_COMMIT_SHA=([0-9a-f]{40})\s*$", re.MULTILINE)

Sleep = Callable[[float], Awaitable[None]]


class SourceCraftError(Exception):
    def __init__(self, status: int, code: str, message: str) -> None:
        super().__init__(f"{status} {code}: {message}")
        self.status = status
        self.code = code
        self.message = message


class SourceCraftClient:
    def __init__(
        self,
        settings: SourceCraftSettings,
        transport: httpx.AsyncBaseTransport | None = None,
        sleep: Sleep = asyncio.sleep,
    ) -> None:
        self._settings = settings
        self._sleep = sleep
        self._http = httpx.AsyncClient(
            base_url=settings.api_url,
            headers={"Authorization": f"Bearer {settings.token.get_secret_value()}"},
            timeout=settings.timeout,
            transport=transport,
        )

    async def __aenter__(self) -> Self:
        return self

    async def __aexit__(
        self, exc_type: type[BaseException] | None, exc: BaseException | None, tb: TracebackType | None
    ) -> None:
        await self.aclose()

    async def aclose(self) -> None:
        await self._http.aclose()

    def run_url(self, repo: str, run: str) -> str:
        return self._settings.run_url_template.format(repo=repo, run=run)

    async def list_runs(self, repo: str, page_size: int = 20) -> list[Run]:
        """Newest first. One page is enough for the watcher: it only looks for runs of recent pushes."""
        data = await self._get(f"/repos/{repo}/cicd/runs", params={"page_size": page_size})
        return [Run.model_validate(r) for r in data.get("runs", [])]

    async def get_run(self, repo: str, run: str) -> Run:
        return Run.model_validate(await self._get(f"/repos/{repo}/cicd/runs/{run}"))

    async def get_cube_logs(self, repo: str, run: str, workflow: str, task: str, cube: str) -> CubeLog:
        """Concatenate log pages in order; a page that isn't complete yet is the last readable one."""
        parts: list[str] = []
        done = False
        page = 1
        while True:
            try:
                data = await self._get(f"/repos/{repo}/cicd/logs/{run}/{workflow}/{task}/{cube}", params={"page": page})
            except SourceCraftError as e:
                if e.status == 404 and page > 1:
                    break
                raise
            parts.append(data.get("logs", ""))
            done = bool(data.get("done", False))
            if not data.get("page_complete", False):
                break
            page += 1
        return CubeLog(text="".join(parts), done=done)

    async def run_commit_sha(self, repo: str, run: Run) -> str | None:
        """The commit a run was started for, read from the meta cube's log (None if not printed yet)."""
        for workflow in run.workflows:
            if run.task(workflow.slug, META_TASK) is None:
                continue
            try:
                logs = await self.get_cube_logs(repo, run.slug, workflow.slug, META_TASK, META_CUBE)
            except SourceCraftError as e:
                if e.status == 404:
                    return None
                raise
            match = _SHA_LINE.search(logs.text)
            return match.group(1) if match else None
        return None

    async def _get(self, path: str, params: dict[str, Any] | None = None) -> dict[str, Any]:
        attempts = self._settings.max_attempts
        for attempt in range(1, attempts + 1):
            try:
                response = await self._http.get(path, params=params)
            except httpx.TransportError as e:
                if attempt == attempts:
                    raise
                log.warning("sourcecraft %s: %s, retry %d/%d", path, type(e).__name__, attempt, attempts - 1)
            else:
                if response.status_code < 500:
                    return self._parse(response)
                if attempt == attempts:
                    return self._parse(response)
                log.warning("sourcecraft %s: HTTP %d, retry %d/%d", path, response.status_code, attempt, attempts - 1)
            await self._sleep(min(0.5 * 2 ** (attempt - 1), 8.0))
        raise AssertionError("unreachable")

    @staticmethod
    def _parse(response: httpx.Response) -> dict[str, Any]:
        try:
            body = response.json()
        except ValueError:
            body = {}
        if response.status_code >= 400:
            raise SourceCraftError(
                response.status_code,
                str(body.get("error_code", "")),
                str(body.get("message", response.text[:200])),
            )
        if not isinstance(body, dict):
            raise SourceCraftError(response.status_code, "BadResponse", "expected a JSON object")
        return body