"""Knowledge router — ADRs, memories, and file browser for mounted data directory."""

from __future__ import annotations

import json
import os
from pathlib import Path
from typing import Optional

from fastapi import APIRouter, HTTPException
from fastapi.responses import PlainTextResponse

from app.redis_client import get_redis, list_adrs, get_adr, list_memories

router = APIRouter(prefix="/api/v1", tags=["knowledge"])

# Data dir is mounted from DevOpsMCP at /data (read-only bind mount in production)
DATA_DIR = Path(os.environ.get("DATA_DIR", "/data"))
KNOWLEDGE_CATALOG = DATA_DIR / "knowledge" / "catalog.json"


# ── ADRs ──────────────────────────────────────────────────────────────────────

@router.get("/adrs")
def api_list_adrs(status: Optional[str] = None):
    r = get_redis()
    adrs = list_adrs(r, status_filter=status)
    return {"adrs": adrs, "total": len(adrs)}


@router.get("/adrs/{adr_id}")
def api_get_adr(adr_id: str):
    r = get_redis()
    adr = get_adr(r, adr_id)
    if not adr:
        raise HTTPException(status_code=404, detail="ADR not found")
    return adr


# ── Memories ──────────────────────────────────────────────────────────────────

@router.get("/memories")
def api_list_memories(entity_type: Optional[str] = None, limit: int = 50):
    r = get_redis()
    memories = list_memories(r, entity_type=entity_type, limit=limit)
    return {"memories": memories, "total": len(memories)}


# ── Knowledge catalog (file-based, from bind-mounted data dir) ────────────────

@router.get("/knowledge")
def api_list_knowledge(category: Optional[str] = None, tag: Optional[str] = None):
    if not KNOWLEDGE_CATALOG.exists():
        return {"entries": [], "total": 0, "data_dir_available": False}
    try:
        catalog: dict = json.loads(KNOWLEDGE_CATALOG.read_text(encoding="utf-8"))
    except Exception as exc:
        raise HTTPException(status_code=500, detail=f"Catalog read error: {exc}") from exc

    entries = list(catalog.values())
    if category:
        entries = [e for e in entries if e.get("category", "").lower() == category.lower()]
    if tag:
        entries = [e for e in entries if tag.lower() in [t.lower() for t in e.get("tags", [])]]

    summaries = [
        {
            "storage_filename": e["storage_filename"],
            "original_filename": e["original_filename"],
            "title": e.get("title", e["original_filename"]),
            "file_type": e.get("file_type", "markdown"),
            "category": e.get("category", "general"),
            "tags": e.get("tags", []),
            "summary": e.get("summary", "")[:200],
            "char_count": e.get("char_count", 0),
            "learned_at": e.get("learned_at", ""),
        }
        for e in entries
    ]
    summaries.sort(key=lambda e: e.get("learned_at", ""), reverse=True)
    return {"entries": summaries, "total": len(summaries), "data_dir_available": True}


@router.get("/knowledge/{filename}")
def api_get_knowledge_file(filename: str):
    """Return raw markdown content of a knowledge file."""
    safe_name = Path(filename).name  # prevent path traversal
    file_path = DATA_DIR / "knowledge" / safe_name
    if not file_path.exists() or not file_path.is_file():
        raise HTTPException(status_code=404, detail="File not found")
    content = file_path.read_text(encoding="utf-8")
    return PlainTextResponse(content, media_type="text/markdown")


# ── Generic file browser for data directory ───────────────────────────────────

@router.get("/files")
def api_list_files(subdir: str = ""):
    """List files in the bound data directory."""
    target = DATA_DIR / subdir if subdir else DATA_DIR
    target = target.resolve()
    # Safety: must stay within DATA_DIR
    if not str(target).startswith(str(DATA_DIR.resolve())):
        raise HTTPException(status_code=400, detail="Path traversal not allowed")
    if not target.exists():
        return {"files": [], "dirs": [], "path": subdir}
    files = []
    dirs = []
    for item in sorted(target.iterdir()):
        if item.is_file() and item.suffix in {".md", ".yml", ".yaml", ".txt", ".rst", ".json"}:
            files.append({
                "name": item.name,
                "size": item.stat().st_size,
                "path": str(item.relative_to(DATA_DIR)),
            })
        elif item.is_dir():
            dirs.append(item.name)
    return {"files": files, "dirs": dirs, "path": subdir}


@router.get("/files/{file_path:path}")
def api_get_file(file_path: str):
    """Return raw content of a file from the data directory."""
    target = (DATA_DIR / file_path).resolve()
    if not str(target).startswith(str(DATA_DIR.resolve())):
        raise HTTPException(status_code=400, detail="Path traversal not allowed")
    if not target.exists() or not target.is_file():
        raise HTTPException(status_code=404, detail="File not found")
    allowed = {".md", ".yml", ".yaml", ".txt", ".rst"}
    if target.suffix not in allowed:
        raise HTTPException(status_code=400, detail="File type not allowed")
    content = target.read_text(encoding="utf-8")
    media_type = "text/markdown" if target.suffix == ".md" else "text/plain"
    return PlainTextResponse(content, media_type=media_type)