"""REST API for the plan-review page: read the plan, comment, approve, or request
changes — all plain HTTP, no CRDT/WebSocket.

Reviewers leave whole-document comments via this API; they're stored server-side
and listed for everyone who can read the thread. On approve/reject the comments
are read back here, formatted, and handed to the agent as the instruction for the
follow-up run. The agent never sees comments during review — only this aggregated
feedback at the decision point.

Permissions: any authenticated org member can read a surfaced thread, comment, and
request changes (reject); only the thread owner can approve. A comment can be
deleted by its author or the thread owner.
"""

from __future__ import annotations

import logging
from typing import Any

from fastapi import APIRouter, Depends, HTTPException
from langgraph_sdk import get_client
from pydantic import BaseModel

from ..dispatch import dispatch_agent_run
from ..utils.slack import post_slack_thread_reply
from .oauth import require_same_origin_for_mutations, require_session
from .plan_store import (
    PLAN_STATUS_APPROVED,
    PLAN_STATUS_CANCELLED,
    PLAN_STATUS_READY,
    PLAN_STATUS_REVISING,
    PLAN_STATUS_SHARED,
    add_plan_comment,
    delete_plan_comment,
    get_plan_content,
    list_plan_comments,
    save_plan_content,
    set_plan_status,
    write_plan_to_sandbox,
)
from .thread_api import (
    _repo_config_from_metadata,
    _thread_is_readable,
    _thread_source,
    _user_owns_thread,
)

logger = logging.getLogger(__name__)

plan_router = APIRouter(
    prefix="/dashboard/api/plan",
    tags=["plan"],
    dependencies=[Depends(require_same_origin_for_mutations)],
)
_SESSION_DEP = Depends(require_session)


class CommentBody(BaseModel):
    body: str


class PlanUpdate(BaseModel):
    markdown: str


async def _thread_metadata(thread_id: str) -> dict[str, Any]:
    client = get_client()
    try:
        thread = await client.threads.get(thread_id)
    except Exception as exc:  # noqa: BLE001
        raise HTTPException(404, "thread not found") from exc
    metadata = (
        thread.get("metadata") if isinstance(thread, dict) else getattr(thread, "metadata", None)
    )
    return metadata if isinstance(metadata, dict) else {}


@plan_router.get("/{thread_id}")
async def get_plan(thread_id: str, session: dict[str, Any] = _SESSION_DEP) -> dict[str, Any]:
    metadata = await _thread_metadata(thread_id)
    if not _thread_is_readable(metadata):
        raise HTTPException(404, "thread not found")
    login = session["sub"]
    email = session.get("email")
    content = await get_plan_content(thread_id) or {}
    return {
        "threadId": thread_id,
        "status": content.get("status") or metadata.get("plan_status") or "planning",
        "markdown": content.get("markdown", ""),
        "isOwner": _user_owns_thread(metadata, login, email),
        "user": {
            "id": login,
            "login": login,
            "email": email,
            "name": session.get("name") or login,
        },
    }


@plan_router.put("/{thread_id}")
async def update_plan(
    thread_id: str, body: PlanUpdate, session: dict[str, Any] = _SESSION_DEP
) -> dict[str, Any]:
    """Owner-only manual edit of the plan markdown.

    Re-publishes the edited plan as ``ready`` (and mirrors it into the sandbox
    ``plan.md``) while preserving reviewer comments, so the owner can refine the
    plan before approving it."""
    metadata = await _thread_metadata(thread_id)
    if not _user_owns_thread(metadata, session["sub"], session.get("email")):
        raise HTTPException(403, "only the plan owner can edit the plan")
    markdown = body.markdown.strip()
    if not markdown:
        raise HTTPException(422, "plan markdown cannot be empty")
    content = await get_plan_content(thread_id) or {}
    _reject_shared_content(content)
    status = content.get("status") or metadata.get("plan_status") or "planning"
    if status in (PLAN_STATUS_APPROVED, PLAN_STATUS_CANCELLED):
        raise HTTPException(409, f"cannot edit a {status} plan")
    await save_plan_content(
        thread_id, markdown=markdown, status=PLAN_STATUS_READY, clear_comments=False
    )
    await write_plan_to_sandbox(thread_id, markdown)
    return {"status": PLAN_STATUS_READY, "markdown": markdown}


@plan_router.get("/{thread_id}/comments")
async def get_plan_comments(
    thread_id: str, session: dict[str, Any] = _SESSION_DEP
) -> dict[str, Any]:
    metadata = await _thread_metadata(thread_id)
    if not _thread_is_readable(metadata):
        raise HTTPException(404, "thread not found")
    return {"comments": await list_plan_comments(thread_id)}


@plan_router.post("/{thread_id}/comments")
async def post_plan_comment(
    thread_id: str, body: CommentBody, session: dict[str, Any] = _SESSION_DEP
) -> dict[str, Any]:
    metadata = await _thread_metadata(thread_id)
    if not _thread_is_readable(metadata):
        raise HTTPException(404, "thread not found")
    _reject_shared_content(await get_plan_content(thread_id) or {})
    text = body.body.strip()
    if not text:
        raise HTTPException(422, "comment body cannot be empty")
    login = session["sub"]
    return await add_plan_comment(
        thread_id, author=session.get("name") or login, author_login=login, body=text
    )


@plan_router.delete("/{thread_id}/comments/{comment_id}")
async def remove_plan_comment(
    thread_id: str, comment_id: str, session: dict[str, Any] = _SESSION_DEP
) -> dict[str, Any]:
    metadata = await _thread_metadata(thread_id)
    if not _thread_is_readable(metadata):
        raise HTTPException(404, "thread not found")
    _reject_shared_content(await get_plan_content(thread_id) or {})
    comments = await list_plan_comments(thread_id)
    target = next((c for c in comments if c.get("id") == comment_id), None)
    if target is None:
        raise HTTPException(404, "comment not found")
    login = session["sub"]
    is_owner = _user_owns_thread(metadata, login, session.get("email"))
    if target.get("author_login") != login and not is_owner:
        raise HTTPException(403, "only the author or the plan owner can delete a comment")
    await delete_plan_comment(thread_id, comment_id)
    return {"ok": True}


@plan_router.post("/{thread_id}/approve")
async def approve_plan(thread_id: str, session: dict[str, Any] = _SESSION_DEP) -> dict[str, Any]:
    metadata = await _thread_metadata(thread_id)
    if not _user_owns_thread(metadata, session["sub"], session.get("email")):
        raise HTTPException(403, "only the plan owner can approve")
    # Read the published plan + comments BEFORE mutating state: a store failure
    # here aborts the decision (500) rather than dispatching without them. The
    # published markdown may have been edited by the owner, so it is the
    # source of truth handed to the agent (not its own stale history) — read it
    # strictly so a transient failure can't silently drop the edit.
    content = await get_plan_content(thread_id, raise_on_error=True) or {}
    _reject_shared_content(content)
    status = content.get("status") or metadata.get("plan_status") or "planning"
    if status == PLAN_STATUS_APPROVED:
        # Idempotent: a repeat approve (double-click / retry) must not dispatch a
        # second implementation run or post a duplicate Slack notice.
        raise HTTPException(409, "plan is already approved")
    plan_markdown = str(content.get("markdown", "")).strip()
    comments = await list_plan_comments(thread_id, raise_on_error=True)
    feedback = _format_comments(comments)
    if plan_markdown:
        text = (
            "The plan has been approved. Implement it now as described below:\n\n" + plan_markdown
        )
        if feedback:
            text += f"\n\nAlso take this reviewer feedback into account:\n\n{feedback}"
    elif feedback:
        text = (
            "The plan has been approved. Implement it now, taking this reviewer "
            f"feedback into account:\n\n{feedback}"
        )
    else:
        text = "The plan has been approved. Implement it now as described in the plan."
    # Dispatch the implementation run BEFORE persisting APPROVED: if the dispatch
    # fails, the plan stays re-approvable rather than stuck approved-but-undispatched.
    await _dispatch_followup(thread_id, metadata, text, plan_mode=False)
    await set_plan_status(thread_id, PLAN_STATUS_APPROVED, plan_mode=False)
    await _maybe_post_plan_approved_to_slack(
        metadata,
        comment_count=_substantive_comment_count(comments),
        actor=_approval_actor_name(session),
    )
    return {"status": PLAN_STATUS_APPROVED}


@plan_router.post("/{thread_id}/reject")
async def reject_plan(thread_id: str, session: dict[str, Any] = _SESSION_DEP) -> dict[str, Any]:
    metadata = await _thread_metadata(thread_id)
    if not _thread_is_readable(metadata):
        raise HTTPException(404, "thread not found")
    content = await get_plan_content(thread_id, raise_on_error=True) or {}
    _reject_shared_content(content)
    feedback = _format_comments(await list_plan_comments(thread_id, raise_on_error=True))
    await set_plan_status(thread_id, PLAN_STATUS_REVISING, plan_mode=True)
    text = (
        "The plan needs changes before implementation. Address this reviewer "
        "feedback in the existing Markdown file under /workspace/plans/, then "
        "publish an updated plan with the save_plan tool:\n\n"
        f"{feedback or '(no specific comments were left)'}"
    )
    await _dispatch_followup(thread_id, metadata, text, plan_mode=True)
    return {"status": PLAN_STATUS_REVISING}


def _reject_shared_content(content: dict[str, Any]) -> None:
    if content.get("status") == PLAN_STATUS_SHARED:
        raise HTTPException(409, "shared content is not an implementation plan")


def _format_comments(comments: list[dict[str, Any]]) -> str:
    lines: list[str] = []
    index = 1
    for comment in comments:
        body = str(comment.get("body", "")).strip()
        if not body:
            continue
        author = str(comment.get("author") or "reviewer").strip()
        lines.append(f"{index}. {author}: {body}")
        index += 1
    return "\n".join(lines)


def _substantive_comment_count(comments: list[dict[str, Any]]) -> int:
    """Count only non-empty comments — the same ones _format_comments feeds the
    agent — so the Slack approval notice doesn't overstate the comment count."""
    return sum(1 for c in comments if str(c.get("body", "")).strip())


def _approval_actor_name(session: dict[str, Any]) -> str:
    return str(session.get("name") or session.get("sub") or "User").strip() or "User"


def _slack_thread_from_metadata(metadata: dict[str, Any]) -> tuple[str, str] | None:
    source_context = metadata.get("source_context")
    if not isinstance(source_context, dict):
        return None
    slack_thread = source_context.get("slack_thread")
    if not isinstance(slack_thread, dict):
        return None
    channel_id = slack_thread.get("channel_id")
    thread_ts = slack_thread.get("thread_ts")
    if isinstance(channel_id, str) and channel_id and isinstance(thread_ts, str) and thread_ts:
        return channel_id, thread_ts
    return None


def _plan_approved_slack_text(comment_count: int, actor: str) -> str:
    return f"Plan approved with {comment_count} comments by {actor}\nbeginning implementation"


async def _maybe_post_plan_approved_to_slack(
    metadata: dict[str, Any], *, comment_count: int, actor: str
) -> None:
    slack_thread = _slack_thread_from_metadata(metadata)
    if slack_thread is None:
        return
    channel_id, thread_ts = slack_thread
    text = _plan_approved_slack_text(comment_count, actor)
    try:
        posted = await post_slack_thread_reply(channel_id, thread_ts, text)
    except Exception:  # noqa: BLE001
        logger.warning("Failed to post plan-approval notice to Slack", exc_info=True)
        return
    if not posted:
        logger.warning("Plan-approval Slack notice was not posted (channel=%s)", channel_id)


async def _dispatch_followup(
    thread_id: str, metadata: dict[str, Any], text: str, *, plan_mode: bool
) -> None:
    """Continue the existing thread with a new instruction run.

    Runs on the same LangGraph thread, so the agent resumes from the checkpoint
    with the full planning history plus this instruction. The configurable is
    rebuilt from the thread's stored owner/repo/Slack context so the agent can
    push, open a PR, and reply in the original channel.
    """
    configurable: dict[str, Any] = {
        "thread_id": thread_id,
        "source": _thread_source(metadata) or "slack",
    }
    email = metadata.get("triggering_user_email")
    if isinstance(email, str) and email:
        configurable["user_email"] = email
    login = metadata.get("github_login")
    if isinstance(login, str) and login:
        configurable["github_login"] = login
    repo = _repo_config_from_metadata(metadata)
    if repo:
        configurable["repo"] = repo
    source_context = metadata.get("source_context")
    if isinstance(source_context, dict):
        slack_thread = source_context.get("slack_thread")
        if isinstance(slack_thread, dict):
            configurable["slack_thread"] = slack_thread
    # Carry the decision to the follow-up run: approve continues out of plan
    # mode (implement), reject stays in plan mode (revise the plan).
    configurable["plan_mode"] = plan_mode

    await dispatch_agent_run(
        thread_id,
        text,
        configurable,
        source=configurable["source"],
    )