"""Governed mutation commands for repository-owned intake and decision records."""

from __future__ import annotations

import re
import uuid
from pathlib import Path
from typing import Any

import yaml

from repo_manager import dual_run, idempotency
from repo_manager.commands.workplan import CommandResult
from repo_manager.gitops import GitError, commit_paths, head_sha, push_ff
from repo_manager.index_store import append_event, default_index_path, save_index
from repo_manager.observe import observe_repository
from repo_manager.parse.record import iter_record_files, parse_record_file
from repo_manager.time import utc_now_text

_ID_RE = re.compile(r"^[A-Za-z0-9][A-Za-z0-9._:-]{1,127}$")
_PROTECTED = frozenset(
    {
        "id",
        "kind",
        "title",
        "status",
        "notes",
        "created",
        "updated",
        "routed_at",
        "closed_at",
        "decided_at",
    }
)
_OPERATIONS = {
    "intake": frozenset({"create", "route", "note", "close"}),
    "decision": frozenset({"create", "update", "resolve"}),
}


def _now() -> str:
    return utc_now_text()


def _reject(command: str, correlation_id: str, code: str, message: str, **evidence: Any) -> CommandResult:
    return CommandResult(
        command=command,
        status="rejected",
        correlation_id=correlation_id,
        evidence={"status": "rejected", **evidence},
        error={"code": code, "message": message, "correlation_id": correlation_id},
    )


def _command(kind: str, operation: str) -> str:
    verbs = {
        ("intake", "create"): "repo.work.create_intake",
        ("intake", "route"): "repo.work.route_intake",
        ("intake", "note"): "repo.work.add_intake_note",
        ("intake", "close"): "repo.work.close_intake",
        ("decision", "create"): "repo.work.create_decision",
        ("decision", "update"): "repo.work.update_decision",
        ("decision", "resolve"): "repo.work.resolve_decision",
    }
    return verbs.get((kind, operation), f"repo.work.{operation}_{kind}")


def _default_path(repo_root: Path, kind: str) -> Path:
    return repo_root / f"{kind}s" / f"{kind}s.md"


def _find(repo_root: Path, kind: str, record_id: str) -> list[tuple[Path, Any]]:
    found: list[tuple[Path, Any]] = []
    for path in iter_record_files(repo_root):
        for record in parse_record_file(path, repo_root=repo_root):
            if record.kind == kind and (record.id == record_id or record.uuid == record_id):
                found.append((path, record))
    return found


def _dump_block(record: dict[str, Any]) -> str:
    return "```yaml\n" + yaml.safe_dump(record, sort_keys=False, allow_unicode=True).rstrip() + "\n```"


def _write_new(path: Path, kind: str, record: dict[str, Any]) -> None:
    path.parent.mkdir(parents=True, exist_ok=True)
    previous = path.read_text(encoding="utf-8") if path.is_file() else f"# {kind.title()} records\n"
    text = previous.rstrip() + f"\n\n## {record['id']} — {record['title']}\n\n" + _dump_block(record) + "\n"
    path.write_text(text, encoding="utf-8")


def _replace(path: Path, record: Any, data: dict[str, Any]) -> None:
    text = path.read_text(encoding="utf-8")
    updated = text[: record.block_start] + _dump_block(data) + text[record.block_end :]
    path.write_text(updated, encoding="utf-8")


def mutate_record(
    repo_root: Path,
    kind: str,
    record_id: str,
    *,
    operation: str,
    title: str | None = None,
    status: str | None = None,
    data: dict[str, Any] | None = None,
    route_to: str | None = None,
    note: str | None = None,
    author: str | None = None,
    outcome: str | None = None,
    rationale: str | None = None,
    decided_by: str | None = None,
    correlation_id: str | None = None,
    reason: str = "rmgr command",
    commit: bool = True,
    push: bool = False,
    expected_head_sha: str | None = None,
    idempotency_key: str | None = None,
    repo_slug: str | None = None,
) -> CommandResult:
    """Mutate one intake or decision YAML block in its authoritative Markdown file."""
    correlation_id = correlation_id or str(uuid.uuid4())
    command = _command(kind, operation)
    repo_root = repo_root.resolve()
    payload = {
        "repo_root": str(repo_root),
        "kind": kind,
        "record_id": record_id,
        "operation": operation,
        "title": title,
        "status": status,
        "data": data,
        "route_to": route_to,
        "note": note,
        "author": author,
        "outcome": outcome,
        "rationale": rationale,
        "decided_by": decided_by,
        "expected_head_sha": expected_head_sha,
    }
    digest = idempotency.payload_hash(payload)
    if idempotency_key:
        prior = idempotency.get(idempotency_key)
        if prior:
            if prior.get("payload_hash") != digest:
                return _reject(command, correlation_id, "conflict", "idempotency key reused")
            previous = prior.get("result") or {}
            return CommandResult(
                command=previous.get("command", command),
                status=previous.get("status", "applied"),
                correlation_id=previous.get("correlation_id", correlation_id),
                evidence=previous.get("evidence") or {"status": "applied", "replay": True},
                error=previous.get("error"),
            )

    if kind not in _OPERATIONS or operation not in _OPERATIONS[kind]:
        return _reject(command, correlation_id, "validation_error", f"invalid {kind!r} operation {operation!r}")
    if not _ID_RE.fullmatch(record_id):
        return _reject(command, correlation_id, "validation_error", f"invalid record id {record_id!r}")
    if data is not None and not isinstance(data, dict):
        return _reject(command, correlation_id, "validation_error", "data must be an object")
    protected = _PROTECTED.intersection(data or {})
    if protected:
        return _reject(
            command,
            correlation_id,
            "validation_error",
            f"data contains protected fields: {', '.join(sorted(protected))}",
        )

    current_head = head_sha(repo_root)
    if expected_head_sha and current_head and current_head != expected_head_sha:
        result = _reject(
            command,
            correlation_id,
            "precondition_failed",
            f"expected_head_sha {expected_head_sha} != {current_head}",
            head_sha=current_head,
        )
        if result.error:
            result.error["retryable"] = True
        return result

    matches = _find(repo_root, kind, record_id)
    if len(matches) > 1:
        return _reject(command, correlation_id, "conflict", f"record {record_id!r} is duplicated")
    match = matches[0] if matches else None
    now = _now()

    if operation == "create":
        if match:
            return _reject(command, correlation_id, "conflict", f"record {record_id!r} exists")
        if not title or not title.strip():
            return _reject(command, correlation_id, "validation_error", "create requires title")
        record_data: dict[str, Any] = {
            "id": record_id,
            "kind": kind,
            "title": title.strip(),
            "status": status or "open",
            **(data or {}),
            "created": now,
            "updated": now,
        }
        path = _default_path(repo_root, kind)
        _write_new(path, kind, record_data)
    else:
        if not match:
            return _reject(command, correlation_id, "not_found", f"record {record_id!r} not found")
        path, parsed = match
        record_data = dict(parsed.raw)
        if kind == "intake" and operation == "route":
            if not route_to or not route_to.strip():
                return _reject(command, correlation_id, "validation_error", "route requires route_to")
            record_data.update(status="routed", routed_to=route_to.strip(), routed_at=now)
        elif kind == "intake" and operation == "note":
            if not note or not note.strip():
                return _reject(command, correlation_id, "validation_error", "note requires content")
            record_data.setdefault("notes", []).append(
                {"content": note.strip(), "author": author or "codex", "created": now}
            )
        elif kind == "intake" and operation == "close":
            record_data.update(status="closed", closed_at=now)
            if outcome:
                record_data["outcome"] = outcome.strip()
        elif kind == "decision" and operation == "update":
            if title is None and status is None and not data:
                return _reject(command, correlation_id, "validation_error", "update requires a field")
            if title is not None:
                if not title.strip():
                    return _reject(command, correlation_id, "validation_error", "title cannot be empty")
                record_data["title"] = title.strip()
            if status is not None:
                if not status.strip():
                    return _reject(command, correlation_id, "validation_error", "status cannot be empty")
                record_data["status"] = status.strip()
            record_data.update(data or {})
        else:
            if not rationale or not rationale.strip() or not decided_by or not decided_by.strip():
                return _reject(
                    command,
                    correlation_id,
                    "validation_error",
                    "resolve requires rationale and decided_by",
                )
            record_data.update(
                status="resolved",
                rationale=rationale.strip(),
                decided_by=decided_by.strip(),
                decided_at=now,
            )
        record_data["updated"] = now
        _replace(path, parsed, record_data)

    relative_path = str(path.relative_to(repo_root))
    git_sha: str | None = None
    push_ok: bool | None = None
    push_message: str | None = None
    if commit:
        try:
            git_sha = commit_paths(
                repo_root,
                [relative_path],
                message=(
                    f"{command} {record_id}\n\n"
                    f"correlation_id: {correlation_id}\nreason: {reason}\nsource: repo-manager\n"
                ),
            )
        except GitError as exc:
            return CommandResult(
                command=command,
                status="failed",
                correlation_id=correlation_id,
                evidence={"status": "failed", "files_touched": [relative_path], "git_sha": None},
                error={"code": "internal", "message": str(exc), "correlation_id": correlation_id},
            )
        if push:
            push_ok, push_message = push_ff(repo_root)

    snapshot, index = observe_repository(repo_root, slug=repo_slug)
    append_event(
        index,
        {
            "type": "repo.command.applied",
            "command": command,
            "operation": operation,
            "correlation_id": correlation_id,
            "kind": kind,
            "id": record_id,
            "git_sha": git_sha,
            "files_touched": [relative_path],
            "source": "repo-manager",
        },
    )
    save_index(index)
    dual_run.record_mutation(
        source="repo-manager",
        kind=f"{kind}_{operation}",
        repo_slug=repo_slug or snapshot.get("slug"),
        detail={"id": record_id, "git_sha": git_sha, "correlation_id": correlation_id},
    )
    evidence: dict[str, Any] = {
        "status": "applied",
        "git_sha": git_sha,
        "files_touched": [relative_path],
        "index_path": str(default_index_path(repo_root)),
        "source": "repo-manager",
    }
    if push:
        evidence.update(push_ok=push_ok, push_message=push_message)
    result = CommandResult(command=command, status="applied", correlation_id=correlation_id, evidence=evidence)
    if idempotency_key:
        idempotency.put(idempotency_key, digest, result.to_dict())
    return result