"""
Roadmap view: loads data/roadmap.yaml, sorts and renders with filters.

Query params (all optional):
- q=...                 (substring search over title/goal/id)
- tag=tag1&tag=tag2     (multi; include if item has ALL selected tags)
- min_priority=1..9     (int; keep items with priority >= this)
- milestone=v0.2        (string; exact match on milestone)
- section=roadmap|backlog|open_questions  (default=roadmap)
"""

from __future__ import annotations
from dataclasses import dataclass, field
from functools import lru_cache
from pathlib import Path
from typing import Any, Dict, List, Optional, Tuple

import time
import yaml
from flask import Blueprint, render_template, request, abort, current_app

from app.logging_setup import get_app_logger
logger = get_app_logger()

bp = Blueprint("roadmap", __name__)

@dataclass
class RoadmapItem:
    id: str
    title: str
    goal: str
    tags: List[str] = field(default_factory=list)
    priority: Optional[int] = None
    milestone: Optional[str] = None
    details: List[str] = field(default_factory=list)


@dataclass
class RoadmapData:
    updated: Optional[str]
    roadmap: List[RoadmapItem]
    backlog: List[RoadmapItem]
    open_questions: List[RoadmapItem]

def _normalize_details(val) -> List[str]:
    # Accept string (block scalar) or list of strings; normalize to list[str]
    if not val:
        return []
    if isinstance(val, str):
        # split on blank lines while preserving paragraphs
        parts = [p.strip() for p in val.strip().split("\n\n")]
        return [p for p in parts if p]
    if isinstance(val, list):
        return [str(x) for x in val if str(x).strip()]
    # Fallback: stringify unknown types
    return [str(val)]

def _to_items(raw: List[Dict[str, Any]]) -> List[RoadmapItem]:
    items: List[RoadmapItem] = []
    for obj in raw or []:
        items.append(
            RoadmapItem(
                id=str(obj.get("id", "")),
                title=str(obj.get("title", "")),
                goal=str(obj.get("goal", "")),
                tags=list(obj.get("tags", []) or []),
                priority=obj.get("priority"),
                milestone=obj.get("milestone"),
                details=_normalize_details(obj.get("details")),
            )
        )
    return items


def load_roadmap() -> RoadmapData:
    """Load YAML and return structured RoadmapData (no caching)."""
    path = Path(current_app.config.get("ROADMAP_FILE"))
    with path.open("r", encoding="utf-8") as f:
        raw = yaml.safe_load(f) or {}

    return RoadmapData(
        updated=raw.get("updated"),
        roadmap=_to_items(raw.get("roadmap", [])),
        backlog=_to_items(raw.get("backlog", [])),
        open_questions=_to_items(raw.get("open_questions", [])),
    )


def _apply_filters(
    items: List[RoadmapItem],
    query: str,
    tags: List[str],
    min_priority: Optional[int],
    milestone: Optional[str],
) -> List[RoadmapItem]:
    def matches(item: RoadmapItem) -> bool:
        # text search over id/title/goal
        if query:
            hay = f"{item.id} {item.title} {item.goal}".lower()
            if query not in hay:
                return False

        # tag filter (AND)
        if tags:
            if not set(tags).issubset(set(item.tags)):
                return False

        # min priority
        if min_priority is not None and item.priority is not None:
            if item.priority < min_priority:
                return False

        # milestone
        if milestone:
            if (item.milestone or "").strip() != milestone.strip():
                return False

        return True

    # sort: priority asc (None last), then title
    def sort_key(i: RoadmapItem) -> Tuple[int, str]:
        pri = i.priority if i.priority is not None else 9999
        return (pri, i.title.lower())

    return sorted([i for i in items if matches(i)], key=sort_key)


def _collect_all_tags(data: RoadmapData) -> List[str]:
    seen = set()
    for col in (data.roadmap, data.backlog, data.open_questions):
        for i in col:
            for t in i.tags:
                seen.add(t)
    return sorted(seen)


@bp.route("/roadmap")
def roadmap_view():
    data = load_roadmap()

    # which column?
    section = request.args.get("section", "roadmap")
    if section not in {"roadmap", "backlog", "open_questions"}:
        abort(400, "invalid section")

    # filters
    q = (request.args.get("q") or "").strip().lower()
    tags = request.args.getlist("tag")
    min_priority = request.args.get("min_priority")
    milestone = request.args.get("milestone") or None
    try:
        min_priority_val = int(min_priority) if min_priority else None
    except ValueError:
        min_priority_val = None

    # pick list + filter
    source = getattr(data, section)
    items = _apply_filters(source, q, tags, min_priority_val, milestone)

    # tag universe for sidebar chips
    all_tags = _collect_all_tags(data)

    return render_template(
        "roadmap.html",
        updated=data.updated,
        section=section,
        items=items,
        all_tags=all_tags,
        q=q,
        selected_tags=tags,
        min_priority=min_priority_val,
        milestone=milestone,
    )