"""Knowledge router — ADRs, memories, knowledge catalog, HOWTOs, agents, skills via MCP proxy."""

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
import app.mcp_client as mcp

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

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 — MCP proxy (file-based in DevOpsMCP) ──────────────────

@router.get("/knowledge")
async def api_list_knowledge(category: Optional[str] = None, tag: Optional[str] = None):
    try:
        return await mcp.list_knowledge(category=category, tag=tag)
    except Exception as exc:
        # Fallback: try local bind-mount
        if not KNOWLEDGE_CATALOG.exists():
            return {"entries": [], "total": 0, "error": str(exc)}
        try:
            catalog = json.loads(KNOWLEDGE_CATALOG.read_text(encoding="utf-8"))
            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", [])]]
            entries.sort(key=lambda e: e.get("learned_at", ""), reverse=True)
            return {"entries": entries, "total": len(entries)}
        except Exception as e2:
            raise HTTPException(status_code=500, detail=str(e2)) from e2


@router.get("/knowledge/{filename}")
async def api_get_knowledge_file(filename: str):
    try:
        result = await mcp.get_knowledge(filename)
        content = result.get("content", result.get("raw", ""))
        return PlainTextResponse(str(content), media_type="text/markdown")
    except Exception as exc:
        # Fallback: local bind-mount
        safe_name = Path(filename).name
        file_path = DATA_DIR / "knowledge" / safe_name
        if not file_path.exists():
            raise HTTPException(status_code=404, detail="File not found") from exc
        return PlainTextResponse(file_path.read_text(encoding="utf-8"), media_type="text/markdown")


# ── HOWTOs — MCP proxy ────────────────────────────────────────────────────────

@router.get("/howtos")
async def api_list_howtos():
    try:
        return await mcp.list_howtos()
    except Exception as exc:
        raise HTTPException(status_code=502, detail=f"MCP proxy error: {exc}") from exc


@router.get("/howtos/{filename}")
async def api_get_howto(filename: str):
    try:
        result = await mcp.get_howto(filename)
        content = result.get("content", result.get("raw", ""))
        return PlainTextResponse(str(content), media_type="text/markdown")
    except Exception as exc:
        raise HTTPException(status_code=502, detail=f"MCP proxy error: {exc}") from exc


# ── Agents — MCP proxy ────────────────────────────────────────────────────────

@router.get("/agents")
async def api_list_agents(domain: Optional[str] = None):
    try:
        return await mcp.list_agents(domain=domain)
    except Exception as exc:
        raise HTTPException(status_code=502, detail=f"MCP proxy error: {exc}") from exc


@router.get("/agents/{name}")
async def api_get_agent(name: str):
    try:
        return await mcp.get_agent(name)
    except Exception as exc:
        raise HTTPException(status_code=502, detail=f"MCP proxy error: {exc}") from exc


# ── Skills — MCP proxy ────────────────────────────────────────────────────────

@router.get("/skills")
async def api_list_skills(domain: Optional[str] = None):
    try:
        return await mcp.list_skills(domain=domain)
    except Exception as exc:
        raise HTTPException(status_code=502, detail=f"MCP proxy error: {exc}") from exc


@router.get("/skills/{name}")
async def api_get_skill(name: str):
    try:
        return await mcp.get_skill(name)
    except Exception as exc:
        raise HTTPException(status_code=502, detail=f"MCP proxy error: {exc}") from exc


# ── Generic file browser (bind-mount fallback) ────────────────────────────────

@router.get("/files")
def api_list_files(subdir: str = ""):
    target = (DATA_DIR / subdir if subdir else DATA_DIR).resolve()
    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, "available": False}
    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, "available": True}