from __future__ import annotations

from fastapi import FastAPI, Request, HTTPException, Query
from fastapi.responses import HTMLResponse, FileResponse, PlainTextResponse, JSONResponse, Response
from deck_builder.combos import (
    detect_combos as _detect_combos,
    detect_synergies as _detect_synergies,
)
from tagging.combo_schema import load_and_validate_combos as _load_combos, load_and_validate_synergies as _load_synergies
from fastapi.templating import Jinja2Templates
from fastapi.staticfiles import StaticFiles
from pathlib import Path
import os
import json as _json
import time
import uuid
import logging
from starlette.exceptions import HTTPException as StarletteHTTPException
from starlette.middleware.gzip import GZipMiddleware
from typing import Any, Tuple

# Resolve template/static dirs relative to this file
_THIS_DIR = Path(__file__).resolve().parent
_TEMPLATES_DIR = _THIS_DIR / "templates"
_STATIC_DIR = _THIS_DIR / "static"

app = FastAPI(title="MTG Deckbuilder Web UI")
app.add_middleware(GZipMiddleware, minimum_size=500)

# Mount static if present
if _STATIC_DIR.exists():
    class CacheStatic(StaticFiles):
        async def get_response(self, path, scope):  # type: ignore[override]
            resp = await super().get_response(path, scope)
            try:
                # Add basic cache headers for static assets
                resp.headers.setdefault("Cache-Control", "public, max-age=604800, immutable")
            except Exception:
                pass
            return resp
    app.mount("/static", CacheStatic(directory=str(_STATIC_DIR)), name="static")

# Jinja templates
templates = Jinja2Templates(directory=str(_TEMPLATES_DIR))

# Global template flags (env-driven)
def _as_bool(val: str | None, default: bool = False) -> bool:
    if val is None:
        return default
    return val.strip().lower() in {"1", "true", "yes", "on"}

SHOW_LOGS = _as_bool(os.getenv("SHOW_LOGS"), False)
SHOW_SETUP = _as_bool(os.getenv("SHOW_SETUP"), True)
SHOW_DIAGNOSTICS = _as_bool(os.getenv("SHOW_DIAGNOSTICS"), False)
SHOW_VIRTUALIZE = _as_bool(os.getenv("WEB_VIRTUALIZE"), False)
ENABLE_THEMES = _as_bool(os.getenv("ENABLE_THEMES"), False)
ENABLE_PWA = _as_bool(os.getenv("ENABLE_PWA"), False)
ENABLE_PRESETS = _as_bool(os.getenv("ENABLE_PRESETS"), False)

# Theme default from environment: THEME=light|dark|system (case-insensitive). Defaults to system.
_THEME_ENV = (os.getenv("THEME") or "").strip().lower()
DEFAULT_THEME = "system"
if _THEME_ENV in {"light", "dark", "system"}:
    DEFAULT_THEME = _THEME_ENV

# Expose as Jinja globals so all templates can reference without passing per-view
templates.env.globals.update({
    "show_logs": SHOW_LOGS,
    "show_setup": SHOW_SETUP,
    "show_diagnostics": SHOW_DIAGNOSTICS,
    "virtualize": SHOW_VIRTUALIZE,
    "enable_themes": ENABLE_THEMES,
    "enable_pwa": ENABLE_PWA,
    "enable_presets": ENABLE_PRESETS,
    "default_theme": DEFAULT_THEME,
})

# --- Simple fragment cache for template partials (low-risk, TTL-based) ---
_FRAGMENT_CACHE: dict[Tuple[str, str], tuple[float, str]] = {}
_FRAGMENT_TTL_SECONDS = 60.0

def render_cached(template_name: str, cache_key: str | None, /, **ctx: Any) -> str:
    """Render a template fragment with an optional cache key and short TTL.

    Intended for finished/immutable views (e.g., saved deck summaries). On error,
    falls back to direct rendering without cache interaction.
    """
    try:
        if cache_key:
            now = time.time()
            k = (template_name, str(cache_key))
            hit = _FRAGMENT_CACHE.get(k)
            if hit and (now - hit[0]) < _FRAGMENT_TTL_SECONDS:
                return hit[1]
            html = templates.get_template(template_name).render(**ctx)
            _FRAGMENT_CACHE[k] = (now, html)
            return html
        return templates.get_template(template_name).render(**ctx)
    except Exception:
        return templates.get_template(template_name).render(**ctx)

templates.env.globals["render_cached"] = render_cached

# --- Diagnostics: request-id and uptime ---
_APP_START_TIME = time.time()

@app.middleware("http")
async def request_id_middleware(request: Request, call_next):
    """Assign or propagate a request id and attach to response headers."""
    rid = request.headers.get("X-Request-ID") or uuid.uuid4().hex
    request.state.request_id = rid
    try:
        response = await call_next(request)
    except Exception as ex:
        # Log and re-raise so FastAPI exception handlers can format the response.
        logging.getLogger("web").error(f"Unhandled error [rid={rid}]: {ex}", exc_info=True)
        raise
    response.headers["X-Request-ID"] = rid
    return response


@app.get("/", response_class=HTMLResponse)
async def home(request: Request) -> HTMLResponse:
    return templates.TemplateResponse("home.html", {"request": request, "version": os.getenv("APP_VERSION", "dev")})


# Simple health check (hardened)
@app.get("/healthz")
async def healthz():
    try:
        version = os.getenv("APP_VERSION", "dev")
        uptime_s = int(time.time() - _APP_START_TIME)
        return {"status": "ok", "version": version, "uptime_seconds": uptime_s}
    except Exception:
        # Avoid throwing from health
        return {"status": "degraded"}

# System summary endpoint for diagnostics
@app.get("/status/sys")
async def status_sys():
    try:
        version = os.getenv("APP_VERSION", "dev")
        uptime_s = int(time.time() - _APP_START_TIME)
        server_time = time.strftime("%Y-%m-%dT%H:%M:%SZ", time.gmtime())
        return {
            "version": version,
            "uptime_seconds": uptime_s,
            "server_time_utc": server_time,
            "flags": {
                "SHOW_LOGS": bool(SHOW_LOGS),
                "SHOW_SETUP": bool(SHOW_SETUP),
                "SHOW_DIAGNOSTICS": bool(SHOW_DIAGNOSTICS),
                "ENABLE_THEMES": bool(ENABLE_THEMES),
                "ENABLE_PWA": bool(ENABLE_PWA),
                "ENABLE_PRESETS": bool(ENABLE_PRESETS),
                "DEFAULT_THEME": DEFAULT_THEME,
            },
        }
    except Exception:
        return {"version": "unknown", "uptime_seconds": 0, "flags": {}}

# Logs tail endpoint (read-only)
@app.get("/status/logs")
async def status_logs(
    tail: int = Query(200, ge=1, le=500),
    q: str | None = None,
    level: str | None = Query(None, description="Optional level filter: error|warning|info|debug"),
):
    try:
        if not SHOW_LOGS:
            # Hide when logs are disabled
            return JSONResponse({"error": True, "status": 403, "detail": "Logs disabled"}, status_code=403)
        log_path = Path('logs/deck_builder.log')
        if not log_path.exists():
            return JSONResponse({"lines": [], "count": 0})
        from collections import deque
        with log_path.open('r', encoding='utf-8', errors='ignore') as lf:
            lines = list(deque(lf, maxlen=tail))
        if q:
            ql = q.lower()
            lines = [ln for ln in lines if ql in ln.lower()]
        # Optional level filter (simple substring match)
        if level:
            lv = level.strip().lower()
            # accept warn as alias for warning
            if lv == "warn":
                lv = "warning"
            if lv in {"error", "warning", "info", "debug"}:
                lines = [ln for ln in lines if lv in ln.lower()]
        return JSONResponse({"lines": lines, "count": len(lines)})
    except Exception:
        return JSONResponse({"lines": [], "count": 0})

# Lightweight setup/tagging status endpoint
@app.get("/status/setup")
async def setup_status():
    try:
        p = Path("csv_files/.setup_status.json")
        if p.exists():
            with p.open("r", encoding="utf-8") as f:
                data = _json.load(f)
            # Attach a small log tail if available
            try:
                log_path = Path('logs/deck_builder.log')
                if log_path.exists():
                    tail_lines = []
                    with log_path.open('r', encoding='utf-8', errors='ignore') as lf:
                        # Read last ~100 lines efficiently
                        from collections import deque
                        tail = deque(lf, maxlen=100)
                        tail_lines = list(tail)
                    # Reduce noise: keep lines related to setup/tagging; fallback to last 30 if too few remain
                    try:
                        lowered = [ln for ln in tail_lines]
                        keywords = ["setup", "tag", "color", "csv", "initial setup", "tagging", "load_dataframe"]
                        filtered = [ln for ln in lowered if any(kw in ln.lower() for kw in keywords)]
                        if len(filtered) >= 5:
                            use_lines = filtered[-60:]
                        else:
                            use_lines = tail_lines[-30:]
                        data["log_tail"] = "".join(use_lines).strip()
                    except Exception:
                        data["log_tail"] = "".join(tail_lines).strip()
            except Exception:
                pass
            return JSONResponse(data)
        return JSONResponse({"running": False, "phase": "idle"})
    except Exception:
        return JSONResponse({"running": False, "phase": "error"})

# Routers
from .routes import build as build_routes  # noqa: E402
from .routes import configs as config_routes  # noqa: E402
from .routes import decks as decks_routes  # noqa: E402
from .routes import setup as setup_routes  # noqa: E402
from .routes import owned as owned_routes  # noqa: E402
app.include_router(build_routes.router)
app.include_router(config_routes.router)
app.include_router(decks_routes.router)
app.include_router(setup_routes.router)
app.include_router(owned_routes.router)

# --- Exception handling ---
def _wants_html(request: Request) -> bool:
    try:
        accept = request.headers.get('accept', '')
        is_htmx = request.headers.get('hx-request') == 'true'
        return ("text/html" in accept) and not is_htmx
    except Exception:
        return False


@app.exception_handler(HTTPException)
async def http_exception_handler(request: Request, exc: HTTPException):
    rid = getattr(request.state, "request_id", None) or uuid.uuid4().hex
    logging.getLogger("web").warning(
        f"HTTPException [rid={rid}] {exc.status_code} {request.method} {request.url.path}: {exc.detail}"
    )
    if _wants_html(request):
        # Friendly HTML page
        template = "errors/404.html" if exc.status_code == 404 else "errors/4xx.html"
        try:
            return templates.TemplateResponse(template, {"request": request, "status": exc.status_code, "detail": exc.detail, "request_id": rid}, status_code=exc.status_code, headers={"X-Request-ID": rid})
        except Exception:
            # Fallback plain text
            return PlainTextResponse(f"Error {exc.status_code}: {exc.detail}\nRequest-ID: {rid}", status_code=exc.status_code, headers={"X-Request-ID": rid})
    # JSON structure for HTMX/API
    return JSONResponse(status_code=exc.status_code, content={
        "error": True,
        "status": exc.status_code,
        "detail": exc.detail,
        "request_id": rid,
        "path": str(request.url.path),
    }, headers={"X-Request-ID": rid})


# Also handle Starlette's HTTPException (e.g., 404 route not found)
@app.exception_handler(StarletteHTTPException)
async def starlette_http_exception_handler(request: Request, exc: StarletteHTTPException):
    rid = getattr(request.state, "request_id", None) or uuid.uuid4().hex
    logging.getLogger("web").warning(
        f"HTTPException* [rid={rid}] {exc.status_code} {request.method} {request.url.path}: {exc.detail}"
    )
    if _wants_html(request):
        template = "errors/404.html" if exc.status_code == 404 else "errors/4xx.html"
        try:
            return templates.TemplateResponse(template, {"request": request, "status": exc.status_code, "detail": exc.detail, "request_id": rid}, status_code=exc.status_code, headers={"X-Request-ID": rid})
        except Exception:
            return PlainTextResponse(f"Error {exc.status_code}: {exc.detail}\nRequest-ID: {rid}", status_code=exc.status_code, headers={"X-Request-ID": rid})
    return JSONResponse(status_code=exc.status_code, content={
        "error": True,
        "status": exc.status_code,
        "detail": exc.detail,
        "request_id": rid,
        "path": str(request.url.path),
    }, headers={"X-Request-ID": rid})


@app.exception_handler(Exception)
async def unhandled_exception_handler(request: Request, exc: Exception):
    rid = getattr(request.state, "request_id", None) or uuid.uuid4().hex
    logging.getLogger("web").error(
        f"Unhandled exception [rid={rid}] {request.method} {request.url.path}", exc_info=True
    )
    if _wants_html(request):
        try:
            return templates.TemplateResponse("errors/500.html", {"request": request, "request_id": rid}, status_code=500, headers={"X-Request-ID": rid})
        except Exception:
            return PlainTextResponse(f"Internal Server Error\nRequest-ID: {rid}", status_code=500, headers={"X-Request-ID": rid})
    return JSONResponse(status_code=500, content={
        "error": True,
        "status": 500,
        "detail": "Internal Server Error",
        "request_id": rid,
        "path": str(request.url.path),
    }, headers={"X-Request-ID": rid})

# Lightweight file download endpoint for exports
@app.get("/files")
async def get_file(path: str):
    try:
        p = Path(path)
        if not p.exists() or not p.is_file():
            return PlainTextResponse("File not found", status_code=404)
        # Only allow returning files within the workspace directory for safety
        # (best-effort: require relative to current working directory)
        try:
            cwd = Path.cwd().resolve()
            if cwd not in p.resolve().parents and p.resolve() != cwd:
                # Still allow if under deck_files or config
                allowed = any(seg in ("deck_files", "config", "logs") for seg in p.parts)
                if not allowed:
                    return PlainTextResponse("Access denied", status_code=403)
        except Exception:
            pass
        return FileResponse(path)
    except Exception:
        return PlainTextResponse("Error serving file", status_code=500)

# Serve /favicon.ico from static (prefer .ico, fallback to .png)
@app.get("/favicon.ico")
async def favicon():
    try:
        ico = _STATIC_DIR / "favicon.ico"
        png = _STATIC_DIR / "favicon.png"
        target = ico if ico.exists() else (png if png.exists() else None)
        if target is None:
            return PlainTextResponse("Not found", status_code=404)
        return FileResponse(str(target))
    except Exception:
        return PlainTextResponse("Error", status_code=500)


# Simple Logs page (optional, controlled by SHOW_LOGS)
@app.get("/logs", response_class=HTMLResponse)
async def logs_page(
    request: Request,
    tail: int = Query(200, ge=1, le=500),
    q: str | None = None,
    level: str | None = Query(None),
) -> Response:
    if not SHOW_LOGS:
        # Respect feature flag
        raise HTTPException(status_code=404, detail="Not Found")
    # Reuse status_logs logic
    data = await status_logs(tail=tail, q=q, level=level)  # type: ignore[arg-type]
    lines: list[str]
    if isinstance(data, JSONResponse):
        payload = data.body
        try:
            parsed = _json.loads(payload)
            lines = parsed.get("lines", [])
        except Exception:
            lines = []
    else:
        lines = []
    return templates.TemplateResponse(
        "diagnostics/logs.html",
        {"request": request, "lines": lines, "tail": tail, "q": q or "", "level": (level or "all")},
    )


# Error trigger route for demoing HTMX/global error handling (feature-flagged)
@app.get("/diagnostics/trigger-error")
async def trigger_error(kind: str = Query("http")):
    if kind == "http":
        raise HTTPException(status_code=418, detail="Teapot: example error for testing")
    raise RuntimeError("Example unhandled error for testing")


@app.get("/diagnostics", response_class=HTMLResponse)
async def diagnostics_home(request: Request) -> HTMLResponse:
    if not SHOW_DIAGNOSTICS:
        raise HTTPException(status_code=404, detail="Not Found")
    return templates.TemplateResponse("diagnostics/index.html", {"request": request})


@app.get("/diagnostics/perf", response_class=HTMLResponse)
async def diagnostics_perf(request: Request) -> HTMLResponse:
    """Synthetic scroll performance page (diagnostics only)."""
    if not SHOW_DIAGNOSTICS:
        raise HTTPException(status_code=404, detail="Not Found")
    return templates.TemplateResponse("diagnostics/perf.html", {"request": request})

# --- Diagnostics: combos & synergies ---
@app.post("/diagnostics/combos")
async def diagnostics_combos(request: Request) -> JSONResponse:
    if not SHOW_DIAGNOSTICS:
        raise HTTPException(status_code=404, detail="Diagnostics disabled")
    try:
        payload = await request.json()
    except Exception:
        payload = {}
    names = payload.get("names") or []
    combos_path = payload.get("combos_path") or "config/card_lists/combos.json"
    synergies_path = payload.get("synergies_path") or "config/card_lists/synergies.json"

    combos_model = _load_combos(combos_path)
    synergies_model = _load_synergies(synergies_path)
    combos = _detect_combos(names, combos_path=combos_path)
    synergies = _detect_synergies(names, synergies_path=synergies_path)

    def as_dict_combo(c):
        return {
            "a": c.a,
            "b": c.b,
            "cheap_early": bool(c.cheap_early),
            "setup_dependent": bool(c.setup_dependent),
            "tags": list(c.tags or []),
        }

    def as_dict_syn(s):
        return {"a": s.a, "b": s.b, "tags": list(s.tags or [])}

    return JSONResponse(
        {
            "counts": {"combos": len(combos), "synergies": len(synergies)},
            "versions": {"combos": combos_model.list_version, "synergies": synergies_model.list_version},
            "combos": [as_dict_combo(c) for c in combos],
            "synergies": [as_dict_syn(s) for s in synergies],
        }
    )