"""EEE Validator — HuggingFace Space webhook handler.

Listens for PR events on evaleval/EEE_datastore, validates changed data
files with Pydantic, checks for duplicates, and comments results on the PR.
"""

import logging
import os
import re
import tempfile
import threading
from datetime import datetime, timezone

from huggingface_hub import HfApi, WebhookPayload, WebhooksServer
from huggingface_hub import hf_hub_download
from huggingface_hub.utils import EntryNotFoundError

from dedup import DATASET_REPO_ID, DedupReport, check_duplicates, load_manifest
from post_merge import handle_merge
from validate_data import FileValidationResult, validate_with_pydantic

logging.basicConfig(
    level=logging.INFO,
    format="%(asctime)s %(levelname)s %(name)s: %(message)s",
)
logger = logging.getLogger(__name__)

api = HfApi()


# ---------------------------------------------------------------------------
# Changed file discovery
# ---------------------------------------------------------------------------

def find_changed_files(pr_num: int) -> list[str]:
    """Find added/modified .json and .jsonl files by comparing PR tree to main.

    Falls back to tree comparison since DiscussionWithDetails.diff can be None
    for dataset repos.
    """
    revision = f"refs/pr/{pr_num}"

    def _list_files(rev: str) -> dict[str, str]:
        """Return {path: oid} for all files at a given revision."""
        files = {}
        for entry in api.list_repo_tree(
            repo_id=DATASET_REPO_ID,
            repo_type="dataset",
            revision=rev,
            recursive=True,
        ):
            if hasattr(entry, "rfilename"):
                files[entry.rfilename] = getattr(entry, "oid", None)
        return files

    pr_files = _list_files(revision)
    main_files = _list_files("main")

    changed: list[str] = []
    for path, oid in pr_files.items():
        if not path.startswith("data/"):
            continue
        if not (path.endswith(".json") or path.endswith(".jsonl")):
            continue
        # New file, or existing file with different content
        if path not in main_files or main_files[path] != oid:
            changed.append(path)

    return changed


# ---------------------------------------------------------------------------
# File download
# ---------------------------------------------------------------------------

def download_pr_files(
    file_paths: list[str], pr_num: int, tmp_dir: str
) -> dict[str, str]:
    """Download files from a PR branch and return map of repo-path -> local-path."""
    downloaded: dict[str, str] = {}
    revision = f"refs/pr/{pr_num}"

    for file_path in file_paths:
        try:
            local_path = hf_hub_download(
                repo_id=DATASET_REPO_ID,
                filename=file_path,
                repo_type="dataset",
                revision=revision,
                local_dir=tmp_dir,
            )
            downloaded[file_path] = local_path
            logger.info("Downloaded %s -> %s", file_path, local_path)
        except EntryNotFoundError:
            logger.warning("File not found in PR: %s", file_path)
        except Exception:
            logger.exception("Failed to download %s", file_path)

    return downloaded


# ---------------------------------------------------------------------------
# Validation orchestration
# ---------------------------------------------------------------------------

def validate_files(
    downloaded: dict[str, str],
) -> list[FileValidationResult]:
    """Validate all downloaded files and return results."""
    results: list[FileValidationResult] = []

    for repo_path, local_path in downloaded.items():
        if repo_path.endswith(".jsonl"):
            file_type = "jsonl"
        else:
            file_type = "json"

        result = validate_with_pydantic(local_path, file_type)
        # Store the repo-relative path for reporting
        result.file_path = repo_path
        results.append(result)

    return results


# ---------------------------------------------------------------------------
# Deduplication orchestration
# ---------------------------------------------------------------------------

def run_dedup(
    file_paths: list[str], downloaded: dict[str, str]
) -> DedupReport:
    """Load manifest and check all files for duplicates."""
    manifest = load_manifest(api)

    # Read file contents as bytes
    file_contents: dict[str, bytes] = {}
    for repo_path, local_path in downloaded.items():
        with open(local_path, "rb") as f:
            file_contents[repo_path] = f.read()

    return check_duplicates(file_paths, file_contents, manifest)


# ---------------------------------------------------------------------------
# Comment formatting
# ---------------------------------------------------------------------------

def format_comment(
    pr_num: int,
    validation_results: list[FileValidationResult],
    dedup_report: DedupReport,
) -> str:
    """Format the PR comment as markdown."""
    now = datetime.now(timezone.utc).strftime("%Y-%m-%d %H:%M:%S UTC")
    num_passed = sum(1 for r in validation_results if r.valid)
    num_failed = sum(1 for r in validation_results if not r.valid)
    total = len(validation_results)

    failed = [r for r in validation_results if not r.valid]

    if num_failed == 0:
        status_line = "## ✅ EEE Validation — Ready to Merge"
    else:
        status_line = "## ❌ EEE Validation — Changes Requested"

    lines = [
        status_line,
        f"**PR:** #{pr_num} | **Run:** {now}",
        "",
        f"**{num_passed}/{total} files passed**",
    ]

    if num_failed > 0:
        lines.append("")
        lines.append("### Failures")
        lines.append("| File | Details |")
        lines.append("|------|---------|")
        for r in failed:
            error_summary = "; ".join(r.errors[:5])
            if len(r.errors) > 5:
                error_summary += f" ... and {len(r.errors) - 5} more error(s)"
            lines.append(f"| `{r.file_path}` | {error_summary} |")

    # Dedup section
    has_any_dupes = False
    dedup_lines: list[str] = []
    for dr in dedup_report.results:
        if dr.exact_duplicate_of:
            dedup_lines.append(
                f"- **Exact duplicate:** `{dr.file_path}` is identical to "
                f"existing `{dr.exact_duplicate_of}`"
            )
            has_any_dupes = True
        if dr.near_duplicate_of:
            dedup_lines.append(
                f"- **Potential near-duplicate:** `{dr.file_path}` shares fingerprint "
                f"with existing `{dr.near_duplicate_of}` "
                f"(identical content minus timestamps/UUIDs)"
            )
            has_any_dupes = True

    if has_any_dupes:
        lines.append("")
        lines.append("### Duplicate Check")
        lines.extend(dedup_lines)

    return "\n".join(lines)


# ---------------------------------------------------------------------------
# Core validation logic (shared by webhook + startup sweep)
# ---------------------------------------------------------------------------

REPORT_HEADER = "## ✅ EEE Validation"
REPORT_HEADER_FAIL = "## ❌ EEE Validation"


def process_pr(pr_num: int) -> dict:
    """Run full validation + dedup on a PR and post results as a comment."""
    logger.info("Processing PR #%d", pr_num)

    # Guard: skip if already validated for the current state
    if not pr_needs_validation(pr_num):
        logger.info("PR #%d already validated for current state, skipping", pr_num)
        return {"status": "skipped", "reason": "already validated"}

    # Find changed data files by comparing PR tree to main
    changed_files = find_changed_files(pr_num)
    if not changed_files:
        logger.info("No data files changed in PR #%d", pr_num)
        return {"status": "skipped", "reason": "no data files changed"}

    logger.info("Found %d changed data file(s): %s", len(changed_files), changed_files)

    # Create temp directory for downloads
    tmp_dir = tempfile.mkdtemp(prefix=f"eee_validate_{pr_num}_")

    # Download changed files from the PR branch
    downloaded = download_pr_files(changed_files, pr_num, tmp_dir)
    if not downloaded:
        logger.warning("No files could be downloaded for PR #%d", pr_num)
        return {"status": "error", "reason": "no files downloaded"}

    # Validate files
    validation_results = validate_files(downloaded)

    # Run dedup check
    dedup_report = run_dedup(changed_files, downloaded)

    # Format and post comment
    comment = format_comment(pr_num, validation_results, dedup_report)
    logger.info("Posting validation comment on PR #%d", pr_num)

    api.comment_discussion(
        repo_id=DATASET_REPO_ID,
        discussion_num=pr_num,
        comment=comment,
        repo_type="dataset",
    )

    return {
        "status": "ok",
        "pr": pr_num,
        "files_checked": len(validation_results),
        "passed": sum(1 for r in validation_results if r.valid),
        "failed": sum(1 for r in validation_results if not r.valid),
    }


# ---------------------------------------------------------------------------
# Startup sweep — catch PRs missed while the Space was asleep
# ---------------------------------------------------------------------------

def pr_needs_validation(pr_num: int) -> bool:
    """Check if a PR has commits newer than the last validation report."""
    details = api.get_discussion_details(
        repo_id=DATASET_REPO_ID,
        discussion_num=pr_num,
        repo_type="dataset",
    )
    last_report_time = None
    last_commit_time = None
    for event in details.events:
        if event.type == "comment" and event.content and (
            event.content.startswith(REPORT_HEADER) or event.content.startswith(REPORT_HEADER_FAIL)
        ):
            last_report_time = event.created_at
        if event.type == "commit":
            last_commit_time = event.created_at

    # No report yet — needs validation
    if last_report_time is None:
        return True
    # Has commits after the last report — needs re-validation
    if last_commit_time is not None and last_commit_time > last_report_time:
        return True
    return False


def startup_sweep() -> None:
    """Scan open PRs and validate any that are missing a report."""
    logger.info("Running startup sweep for unvalidated PRs...")
    try:
        discussions = api.get_repo_discussions(
            repo_id=DATASET_REPO_ID,
            repo_type="dataset",
        )
        for disc in discussions:
            if not disc.is_pull_request or disc.status != "open":
                continue
            if not pr_needs_validation(disc.num):
                logger.info("PR #%d is up to date, skipping", disc.num)
                continue
            logger.info("PR #%d needs validation, processing", disc.num)
            try:
                process_pr(disc.num)
            except Exception:
                logger.exception("Startup sweep failed for PR #%d", disc.num)
    except Exception:
        logger.exception("Startup sweep failed to list discussions")
    logger.info("Startup sweep complete")


# Run sweep in background thread so it doesn't block the webhook server startup
threading.Thread(target=startup_sweep, daemon=True).start()


# ---------------------------------------------------------------------------
# Webhook endpoint
# ---------------------------------------------------------------------------

PR_REF_RE = re.compile(r"^refs/pr/(\d+)$")


def _extract_pr_nums_from_refs(payload) -> list[int]:
    """Extract PR numbers from updatedRefs in repo.content events."""
    if not payload.updatedRefs:
        return []
    pr_nums = []
    for ref in payload.updatedRefs:
        m = PR_REF_RE.match(ref.ref)
        if m:
            pr_nums.append(int(m.group(1)))
    return pr_nums


async def validate(payload: WebhookPayload):
    """Handle incoming webhook events from HuggingFace."""
    logger.info("Received webhook event: %s", payload.event)

    # Filter: ignore comments
    if payload.event.scope == "discussion.comment":
        logger.info("Skipping comment event")
        return {"status": "skipped", "reason": "comment event"}

    if payload.repo.type != "dataset":
        logger.info("Skipping non-dataset event (type=%s)", payload.repo.type)
        return {"status": "skipped", "reason": "not a dataset repo"}

    # Route 1: repo.content events (new commits pushed to PR branches)
    if payload.event.scope == "repo.content":
        pr_nums = _extract_pr_nums_from_refs(payload)
        if not pr_nums:
            logger.info("No PR refs in repo.content event")
            return {"status": "skipped", "reason": "no PR refs"}
        results = []
        for pr_num in pr_nums:
            try:
                results.append(process_pr(pr_num))
            except Exception:
                logger.exception("Failed to process PR #%d", pr_num)
                results.append({"status": "error", "pr": pr_num})
        return {"status": "ok", "results": results}

    # Route 2: discussion events (status changes, merges)
    if not payload.discussion or not payload.discussion.isPullRequest:
        logger.info("Skipping non-PR event")
        return {"status": "skipped", "reason": "not a pull request"}

    pr_num = payload.discussion.num

    # Handle merged PRs — update manifest + dataset card
    if payload.discussion.status == "merged":
        try:
            return handle_merge(pr_num)
        except Exception:
            logger.exception("Post-merge failed for PR #%d", pr_num)
            return {"status": "error", "reason": "post-merge failed"}

    # Handle open PRs — validate + dedup
    try:
        return process_pr(pr_num)
    except Exception:
        logger.exception("Failed to process PR #%d", pr_num)
        return {"status": "error", "reason": "processing failed"}


# ---------------------------------------------------------------------------
# Server startup
# ---------------------------------------------------------------------------

if __name__ == "__main__":
    app = WebhooksServer(
        ui=None,  # No UI, just webhook endpoint
        webhook_secret=os.environ.get("WEBHOOKS_SECRET"),
    )
    app.add_webhook(validate)

    # Start the server on port 7860 (HF Spaces default)
    port = int(os.environ.get("PORT", 7860))
    logger.info("Starting webhook server on port %d", port)
    app.launch(server_name="0.0.0.0", server_port=port)