"""GET /api/history; GET /api/history/{prompt_id}/images; GET /api/history/{prompt_id}/file/{filename};
POST /api/history/{prompt_id}/share; DELETE /api/history/{prompt_id}/share"""
from __future__ import annotations

import base64
from typing import Optional

from fastapi import APIRouter, Depends, HTTPException, Query, Request
from fastapi.responses import Response

from web.auth import require_auth

router = APIRouter()


def _assert_owns(prompt_id: str, user: dict) -> None:
    """Raise 404 if the generation doesn't exist or doesn't belong to the user.

    Returning the same 404 for both cases prevents leaking whether a
    prompt_id exists to users who don't own it.  Admins bypass this check.
    """
    if user.get("admin"):
        return
    from generation_db import get_generation
    gen = get_generation(prompt_id)
    if gen is None or gen["user_label"] != user["sub"]:
        raise HTTPException(404, "Not found")


@router.get("")
async def get_history(
    user: dict = Depends(require_auth),
    q: Optional[str] = Query(None, description="Keyword to search in overrides JSON"),
):
    """Return generation history. Admins see all; regular users see only their own.
    Pass ?q=keyword to filter by prompt text or any override field."""
    from generation_db import (
        get_history as db_get_history,
        get_history_for_user,
        search_history,
        search_history_for_user,
    )
    if q and q.strip():
        if user.get("admin"):
            return {"history": search_history(q.strip(), limit=50)}
        return {"history": search_history_for_user(user["sub"], q.strip(), limit=50)}
    if user.get("admin"):
        return {"history": db_get_history(limit=50)}
    return {"history": get_history_for_user(user["sub"], limit=50)}


@router.get("/{prompt_id}/images")
async def get_history_images(prompt_id: str, user: dict = Depends(require_auth)):
    """
    Fetch output files for a past generation.

    Returns base64-encoded blobs from the local SQLite DB — works even after
    ``flush_pending`` has deleted the files from disk.
    """
    _assert_owns(prompt_id, user)
    from generation_db import get_files
    files = get_files(prompt_id)
    if not files:
        raise HTTPException(404, f"No files found for prompt_id {prompt_id!r}")
    return {
        "prompt_id": prompt_id,
        "images": [
            {
                "filename": f["filename"],
                "data": base64.b64encode(f["data"]).decode() if not f["mime_type"].startswith("video/") else None,
                "mime_type": f["mime_type"],
            }
            for f in files
        ],
    }


@router.get("/{prompt_id}/file/{filename}")
async def get_history_file(
    prompt_id: str,
    filename: str,
    request: Request,
    user: dict = Depends(require_auth),
):
    """Stream a single output file, with HTTP range request support for video seeking."""
    _assert_owns(prompt_id, user)
    from generation_db import get_files
    files = get_files(prompt_id)
    matched = next((f for f in files if f["filename"] == filename), None)
    if matched is None:
        raise HTTPException(404, f"File {filename!r} not found for prompt_id {prompt_id!r}")

    data: bytes = matched["data"]
    mime: str = matched["mime_type"]
    total = len(data)

    range_header = request.headers.get("range")
    if range_header:
        range_val = range_header.replace("bytes=", "")
        start_str, _, end_str = range_val.partition("-")
        start = int(start_str) if start_str else 0
        end = int(end_str) if end_str else total - 1
        end = min(end, total - 1)
        chunk = data[start : end + 1]
        return Response(
            content=chunk,
            status_code=206,
            media_type=mime,
            headers={
                "Content-Range": f"bytes {start}-{end}/{total}",
                "Accept-Ranges": "bytes",
                "Content-Length": str(len(chunk)),
            },
        )

    return Response(
        content=data,
        media_type=mime,
        headers={
            "Accept-Ranges": "bytes",
            "Content-Length": str(total),
        },
    )


@router.post("/{prompt_id}/share")
async def create_generation_share(prompt_id: str, user: dict = Depends(require_auth)):
    """Create a share token for a generation. Only the owner may share."""
    # Use the same 404-for-everything helper to avoid leaking prompt_id existence
    _assert_owns(prompt_id, user)
    from generation_db import create_share as db_create_share
    token = db_create_share(prompt_id, user["sub"])
    return {"share_token": token}


@router.delete("/{prompt_id}/share")
async def revoke_generation_share(prompt_id: str, user: dict = Depends(require_auth)):
    """Revoke a share token for a generation. Only the owner may revoke."""
    from generation_db import revoke_share as db_revoke_share
    deleted = db_revoke_share(prompt_id, user["sub"])
    if not deleted:
        raise HTTPException(404, "No active share found for this generation")
    return {"ok": True}