"""Build repository observation + work-record index from files."""

from __future__ import annotations

import re
from pathlib import Path

import yaml

from repo_manager.cache import source_fingerprint
from repo_manager.classification import require_valid_classification
from repo_manager.gitops import head_sha, is_git_repo
from repo_manager.index_store import RepoIndex, WorkRecordEntry, _now
from repo_manager.parse.record import iter_record_files, parse_record_file
from repo_manager.parse.register import iter_register_files, parse_register_file
from repo_manager.parse.workplan import iter_workplan_files, parse_workplan_file


def _slug_from_path(repo_root: Path) -> str:
    return re.sub(r"[^a-z0-9]+", "-", repo_root.name.lower()).strip("-") or "repo"


def load_classification(repo_root: Path) -> dict | None:
    path = repo_root / ".repo-classification.yaml"
    if not path.is_file():
        return None
    data = yaml.safe_load(path.read_text(encoding="utf-8")) or {}
    if isinstance(data, dict) and "repo_classification" in data:
        classification = data["repo_classification"]
    else:
        classification = data if isinstance(data, dict) else None
    if not isinstance(classification, dict):
        return None
    return require_valid_classification(classification)


def observe_repository(repo_root: Path, *, slug: str | None = None) -> tuple[dict, RepoIndex]:
    """Return (RepositorySnapshot-like dict, rebuilt RepoIndex)."""
    repo_root = repo_root.resolve()
    slug = slug or _slug_from_path(repo_root)
    classification = load_classification(repo_root)
    intent_path = None
    description = None
    for name in ("INTENT.md", "GOAL.md"):
        p = repo_root / name
        if p.is_file():
            intent_path = name
            # first non-empty line of body as weak description
            text = p.read_text(encoding="utf-8")
            for line in text.splitlines():
                line = line.strip()
                if line and not line.startswith("#") and not line.startswith("---") and not line.startswith(">"):
                    description = line[:200]
                    break
            break

    records: list[WorkRecordEntry] = []
    for path in iter_workplan_files(repo_root):
        wp = parse_workplan_file(path, repo_root=repo_root)
        records.append(
            WorkRecordEntry(
                kind="workplan",
                id=wp.id,
                status=wp.status,
                title=wp.title,
                source_path=wp.path,
                uuid=wp.state_hub_workstream_id,
                extra={
                    key: wp.frontmatter[key]
                    for key in ("depends_on", "related", "needs_human", "intervention_note")
                    if key in wp.frontmatter
                },
            )
        )
        for task in wp.tasks:
            records.append(
                WorkRecordEntry(
                    kind="task",
                    id=task.id,
                    status=task.status,
                    title=task.title,
                    source_path=wp.path,
                    uuid=task.state_hub_task_id,
                    parent_id=wp.id,
                    extra={
                        key: task.raw[key]
                        for key in ("depends_on", "needs_human", "intervention_note", "blocking_reason")
                        if key in task.raw
                    },
                )
            )

    for path in iter_record_files(repo_root):
        for record in parse_record_file(path, repo_root=repo_root):
            records.append(
                WorkRecordEntry(
                    kind=record.kind,
                    id=record.id,
                    status=record.status,
                    title=record.title,
                    source_path=record.source_path,
                    uuid=record.uuid,
                    extra={"record": record.raw},
                )
            )

    for path in iter_register_files(repo_root):
        for entry in parse_register_file(path, repo_root=repo_root):
            records.append(
                WorkRecordEntry(
                    kind=f"register:{entry.kind}",
                    id=entry.id,
                    status=entry.status,
                    title=entry.title,
                    source_path=entry.source_path,
                    extra={"register_kind": entry.kind, "entry": entry.raw},
                )
            )

    sha = head_sha(repo_root) if is_git_repo(repo_root) else None
    fingerprint, source_files = source_fingerprint(repo_root)
    index = RepoIndex(
        slug=slug,
        repo_root=str(repo_root),
        head_sha=sha,
        observed_at=_now(),
        source_fingerprint=fingerprint,
        source_files=source_files,
        work_records=records,
    )

    snapshot = {
        "api_version": "0.1",
        "slug": slug,
        "lifecycle": "active",
        "domain": (classification or {}).get("domain"),
        "classification": classification,
        "purpose": {
            "description": description,
            "intent_path": intent_path,
        },
        "locations": {
            "repo_root": str(repo_root),
        },
        "revision": {
            "head_sha": sha,
            "observed_at": index.observed_at,
        },
        "index": {
            "workplan_count": sum(1 for r in records if r.kind == "workplan"),
            "task_count": sum(1 for r in records if r.kind == "task"),
            "register_entry_count": sum(1 for r in records if r.kind.startswith("register:")),
            "intake_count": sum(1 for r in records if r.kind == "intake"),
            "decision_count": sum(1 for r in records if r.kind == "decision"),
            "record_count": len(records),
        },
    }
    return snapshot, index