from fastapi import APIRouter, Depends, HTTPException, Query
from fastapi.responses import HTMLResponse
from html import escape as _html_escape
from pydantic import BaseModel, Field
from sqlalchemy import text
from sqlalchemy.orm import Session, joinedload
from app.database import get_db
from app.models import (
    MealPlan, MealPlanItem, MealPlanVote, Recipe, Ingredient,
    FamilyProfile, FamilyMember, ApprovalToken,
    MealPlanStatus, MealPlanItemStatus, MealType, ApprovalTokenStatus
)
from app.schemas import (
    MealPlanResponse, MealPlanCreate,
    MealPlanItemResponse, VoteRequest, VoteResponse
)
from app.security import require_session
from app.services import approval as approval_service
from uuid import UUID
from typing import List, Optional
from datetime import datetime, timedelta
from uuid import UUID
from typing import List, Optional
import random

router = APIRouter()


@router.get("", response_model=Optional[MealPlanResponse])
def get_planned_meals(db: Session = Depends(get_db)):
    profile = db.query(FamilyProfile).first()
    if not profile:
        raise HTTPException(status_code=404, detail="Family profile not found")

    meal_plan = db.query(MealPlan).filter(
        MealPlan.family_profile_id == profile.id
    ).order_by(MealPlan.week_start_date.desc()).first()

    if not meal_plan:
        return None

    return meal_plan


@router.post("", response_model=MealPlanResponse, dependencies=[Depends(require_session)])
def create_meal_plan(meal_plan_data: MealPlanCreate, db: Session = Depends(get_db)):
    profile = db.query(FamilyProfile).first()
    if not profile:
        raise HTTPException(status_code=404, detail="Family profile not found")

    existing = db.query(MealPlan).filter(
        MealPlan.family_profile_id == profile.id,
        MealPlan.week_start_date == meal_plan_data.week_start_date
    ).first()
    if existing:
        raise HTTPException(status_code=400, detail="Meal plan for this week already exists")

    db_meal_plan = MealPlan(
        family_profile_id=profile.id,
        week_start_date=meal_plan_data.week_start_date,
        status=MealPlanStatus[meal_plan_data.status.value.upper()],
        approval_deadline=meal_plan_data.approval_deadline,
        notes=meal_plan_data.notes
    )

    db.add(db_meal_plan)
    db.flush()

    for item_data in meal_plan_data.items:
        db_item = MealPlanItem(
            meal_plan_id=db_meal_plan.id,
            recipe_id=item_data.recipe_id,
            day_of_week=item_data.day_of_week,
            meal_type=MealType[item_data.meal_type.value.upper()],
            estimated_cost=item_data.estimated_cost
        )
        db.add(db_item)

    db.commit()
    db.refresh(db_meal_plan)
    return db_meal_plan


@router.get("/{meal_plan_id}", response_model=MealPlanResponse)
def get_meal_plan(meal_plan_id: UUID, db: Session = Depends(get_db)):
    meal_plan = db.query(MealPlan).filter(MealPlan.id == meal_plan_id).first()
    if not meal_plan:
        raise HTTPException(status_code=404, detail="Meal plan not found")
    return meal_plan


@router.post("/{meal_plan_id}/lock", dependencies=[Depends(require_session)])
def lock_meal_plan(meal_plan_id: UUID, db: Session = Depends(get_db)):
    meal_plan = db.query(MealPlan).filter(MealPlan.id == meal_plan_id).first()
    if not meal_plan:
        raise HTTPException(status_code=404, detail="Meal plan not found")

    meal_plan.status = MealPlanStatus.LOCKED
    db.commit()
    return {"message": "Meal plan locked", "status": meal_plan.status.value}


_DAY_NAMES = {
    1: "Monday", 2: "Tuesday", 3: "Wednesday", 4: "Thursday",
    5: "Friday", 6: "Saturday", 7: "Sunday",
}


class VoteSubmission(BaseModel):
    """Body for POST /vote/{item_id}?token=...

    Spec body: {"vote": "approve" | "deny"}.
    """

    vote: str = Field(..., pattern="^(approve|deny)$")


@router.get("/vote/{item_id}", response_class=HTMLResponse)
def get_vote_page(
    item_id: UUID,
    token: str = Query(..., description="Per-voter signed token"),
    db: Session = Depends(get_db),
):
    """Render the per-voter approval confirmation page.

    Verifies the signed token (no consume) and returns minimal accessible
    HTML with Approve / Deny buttons that POST to the same URL.
    """
    payload = approval_service.verify_token(token)
    if str(payload.get("item")) != str(item_id):
        raise HTTPException(status_code=400, detail="Token not valid for this meal")

    voter = (
        db.query(FamilyMember)
        .filter(FamilyMember.id == UUID(str(payload["voter"])))
        .first()
    )
    if not voter:
        raise HTTPException(status_code=404, detail="Voter not found")

    item = (
        db.query(MealPlanItem)
        .options(joinedload(MealPlanItem.recipe))
        .filter(MealPlanItem.id == item_id)
        .first()
    )
    if not item:
        raise HTTPException(status_code=404, detail="Meal plan item not found")

    recipe_name = item.recipe.name if item.recipe else "Unnamed meal"
    day_name = _DAY_NAMES.get(int(item.day_of_week), str(item.day_of_week))
    meal_type = item.meal_type.value if item.meal_type else ""

    # Token is included only inside the form action (href), never in the
    # visible body. POST is performed by JS so we can submit JSON without
    # leaving the page; non-JS users still get a usable form fallback.
    safe_voter = _html_escape(voter.name)
    safe_recipe = _html_escape(recipe_name)
    safe_day = _html_escape(day_name)
    safe_meal = _html_escape(meal_type)
    action_url = f"/api/meals/vote/{item_id}?token={_html_escape(token, quote=True)}"

    existing_vote = db.query(MealPlanVote).filter(
        MealPlanVote.meal_plan_item_id == item_id,
        MealPlanVote.family_member_id == voter.id,
    ).first()

    if existing_vote:
        already_voted_html = f"""<!doctype html>
<html lang="en">
<head>
<meta charset="utf-8">
<title>Already Voted</title>
<meta name="viewport" content="width=device-width, initial-scale=1">
<style>
 body {{ font-family: system-ui, sans-serif; max-width: 36rem; margin: 2rem auto;
        padding: 0 1rem; color: #111; background: #fff; line-height: 1.5; }}
 h1 {{ font-size: 1.4rem; }}
 .meal {{ padding: 1rem; border: 1px solid #444; border-radius: 6px; margin: 1rem 0; }}
 .already-voted {{ margin-top: 1rem; font-weight: bold; color: #0a6b2b; }}
</style>
</head>
<body>
<h1>Hi {safe_voter}, you already voted on this meal</h1>
<div class="meal">
 <div><strong>{safe_recipe}</strong></div>
 <div>{safe_day} &middot; {safe_meal}</div>
</div>
<div class="already-voted">Your vote has already been recorded. Thank you!</div>
</body>
</html>
"""
        return HTMLResponse(content=already_voted_html, status_code=200)

    html = f"""<!doctype html>
<html lang="en">
<head>
<meta charset="utf-8">
<title>Approve meal</title>
<meta name="viewport" content="width=device-width, initial-scale=1">
<style>
 body {{ font-family: system-ui, sans-serif; max-width: 36rem; margin: 2rem auto;
        padding: 0 1rem; color: #111; background: #fff; line-height: 1.5; }}
 h1 {{ font-size: 1.4rem; }}
 .meal {{ padding: 1rem; border: 1px solid #444; border-radius: 6px; margin: 1rem 0; }}
 button {{ font-size: 1rem; padding: .6rem 1.2rem; margin-right: .5rem;
          border: 2px solid #111; border-radius: 4px; cursor: pointer; }}
 .approve {{ background: #0a6b2b; color: #fff; }}
 .deny {{ background: #b00020; color: #fff; }}
 #status {{ margin-top: 1rem; font-weight: bold; }}
</style>
</head>
<body>
<h1>Hi {safe_voter}, please vote on this meal</h1>
<div class="meal">
 <div><strong>{safe_recipe}</strong></div>
 <div>{safe_day} &middot; {safe_meal}</div>
</div>
<form id="voteForm" method="post" action="{action_url}">
 <button type="submit" name="vote" value="approve" class="approve" aria-label="Approve this meal">Approve</button>
 <button type="submit" name="vote" value="deny" class="deny" aria-label="Deny this meal">Deny</button>
</form>
<div id="status" role="status" aria-live="polite"></div>
<script>
 document.getElementById('voteForm').addEventListener('submit', async function(e) {{
   e.preventDefault();
   var btn = e.submitter || document.activeElement;
   var vote = btn && btn.value ? btn.value : 'approve';
   var resp = await fetch(this.action, {{
     method: 'POST',
     headers: {{ 'Content-Type': 'application/json' }},
     body: JSON.stringify({{ vote: vote }})
   }});
   var data = {{}};
   try {{ data = await resp.json(); }} catch (_) {{}}
   var s = document.getElementById('status');
   if (resp.ok) {{
     s.textContent = 'Recorded: ' + (data.item_status || vote);
   }} else {{
     s.textContent = 'Error: ' + (data.detail || resp.status);
   }}
 }});
</script>
</body>
</html>
"""
    return HTMLResponse(content=html, status_code=200)


@router.post("/vote/{item_id}")
def submit_vote(
    item_id: UUID,
    submission: VoteSubmission,
    token: str = Query(..., description="Per-voter signed token"),
    db: Session = Depends(get_db),
):
    """Record a per-voter vote and apply the approval rule.

    - Single-use enforcement lives in `approval_service.consume_token`.
    - Approval rule: any deny -> item.denied; all-approve -> item.approved;
      otherwise pending (waiting on remaining voters).
    """
    voter = approval_service.consume_token(db, token, item_id)

    item = db.query(MealPlanItem).filter(MealPlanItem.id == item_id).first()
    if not item:
        raise HTTPException(status_code=404, detail="Meal plan item not found")

    vote_bool = submission.vote == "approve"
    db.add(MealPlanVote(
        meal_plan_item_id=item_id,
        family_member_id=voter.id,
        vote=vote_bool,
    ))
    db.flush()

    # Approval rule: count electorate (all family members on this profile)
    # vs votes recorded so far.
    profile_id = item.meal_plan.family_profile_id
    electorate_ids = {
        m.id for m in db.query(FamilyMember)
        .filter(FamilyMember.family_profile_id == profile_id)
        .all()
    }
    votes = db.query(MealPlanVote).filter(
        MealPlanVote.meal_plan_item_id == item_id,
    ).all()

    if any(v.vote is False for v in votes):
        item.approval_status = MealPlanItemStatus.denied
    elif electorate_ids and {v.family_member_id for v in votes} >= electorate_ids:
        item.approval_status = MealPlanItemStatus.approved
    else:
        item.approval_status = MealPlanItemStatus.pending

    db.commit()
    return {"status": "recorded", "item_status": item.approval_status.value}


@router.get("/items/{item_id}", response_model=MealPlanItemResponse)
def get_meal_item(item_id: UUID, db: Session = Depends(get_db)):
    item = db.query(MealPlanItem).options(joinedload(MealPlanItem.recipe)).filter(
        MealPlanItem.id == item_id
    ).first()
    if not item:
        raise HTTPException(status_code=404, detail="Meal plan item not found")

    # Enrich ingredient names from the Ingredient table
    if item.recipe and item.recipe.ingredients:
        ing_ids = [ing.get("ingredient_id") for ing in item.recipe.ingredients if ing.get("ingredient_id")]
        if ing_ids:
            ingredients = db.query(Ingredient).filter(Ingredient.id.in_(ing_ids)).all()
            name_map = {str(i.id): i.name for i in ingredients}
            for ing in item.recipe.ingredients:
                ing_id = str(ing.get("ingredient_id", ""))
                if ing_id in name_map and not ing.get("name"):
                    ing["name"] = name_map[ing_id]

    return item


@router.post("/items/{item_id}/swap", dependencies=[Depends(require_session)])
def swap_meal_item(item_id: UUID, new_recipe_id: UUID, db: Session = Depends(get_db)):
    item = db.query(MealPlanItem).filter(MealPlanItem.id == item_id).first()
    if not item:
        raise HTTPException(status_code=404, detail="Meal plan item not found")

    new_recipe = db.query(Recipe).filter(Recipe.id == new_recipe_id).first()
    if not new_recipe:
        raise HTTPException(status_code=404, detail="New recipe not found")

    item.recipe_id = new_recipe_id
    item.approval_status = MealPlanItemStatus.pending
    item.denial_reason = None
    item.denial_details = None

    db.commit()
    return {"message": "Meal swapped", "item": item}


@router.post("/items/{item_id}/approve")
def approve_meal_item(item_id: UUID, db: Session = Depends(get_db)):
    """Directly approve a meal plan item from the dashboard."""
    item = db.query(MealPlanItem).filter(MealPlanItem.id == item_id).first()
    if not item:
        raise HTTPException(status_code=404, detail="Meal plan item not found")
    item.approval_status = MealPlanItemStatus.approved
    db.commit()
    return {"message": "Meal approved", "item": item}


@router.post("/items/{item_id}/deny")
def deny_meal_item(item_id: UUID, db: Session = Depends(get_db)):
    """Directly deny a meal plan item from the dashboard."""
    item = db.query(MealPlanItem).filter(MealPlanItem.id == item_id).first()
    if not item:
        raise HTTPException(status_code=404, detail="Meal plan item not found")
    item.approval_status = MealPlanItemStatus.denied
    db.commit()
    return {"message": "Meal denied", "item": item}


@router.post("/{meal_plan_id}/generate-item")
def generate_single_item(
    meal_plan_id: UUID,
    day_of_week: int = Query(..., ge=1, le=7),
    meal_type: str = Query(...),
    db: Session = Depends(get_db),
):
    """Generate a single meal for an empty slot."""
    plan = db.query(MealPlan).filter(MealPlan.id == meal_plan_id).first()
    if not plan:
        raise HTTPException(status_code=404, detail="Meal plan not found")

    # Verify slot is empty
    existing = (
        db.query(MealPlanItem)
        .filter(
            MealPlanItem.meal_plan_id == meal_plan_id,
            MealPlanItem.day_of_week == day_of_week,
            MealPlanItem.meal_type == meal_type,
        )
        .first()
    )
    if existing:
        raise HTTPException(status_code=400, detail="Slot already occupied")

    # Get all recipes, score them, pick the best not already in this plan
    all_recipes = db.query(Recipe).all()
    used_ids = {i.recipe_id for i in plan.items if i.recipe_id is not None}

    # Simple heuristic: pick a random un-used recipe (we can improve scoring later)
    available = [r for r in all_recipes if r.id not in used_ids]
    if not available:
        available = all_recipes  # reuse if all recipes are in play

    recipe = random.choice(available)

    new_item = MealPlanItem(
        meal_plan_id=meal_plan_id,
        recipe_id=recipe.id,
        day_of_week=day_of_week,
        meal_type=MealType[meal_type.upper()],
        approval_status=MealPlanItemStatus.pending,
    )
    db.add(new_item)
    db.commit()
    db.refresh(new_item)
    return {"message": "Meal generated", "item": new_item}


@router.put("/items/{item_id}/move")
def move_meal_item(
    item_id: UUID,
    new_day_of_week: int,
    new_meal_type: str,
    db: Session = Depends(get_db),
):
    """Move a meal to a new day/type slot.

    If the target slot is occupied by another item in the same meal plan,
    swap the two items.
    """
    item = db.query(MealPlanItem).filter(MealPlanItem.id == item_id).first()
    if not item:
        raise HTTPException(status_code=404, detail="Meal plan item not found")

    plan_id = item.meal_plan_id
    conflict = (
        db.query(MealPlanItem)
        .filter(
            MealPlanItem.meal_plan_id == plan_id,
            MealPlanItem.day_of_week == new_day_of_week,
            MealPlanItem.meal_type == new_meal_type,
            MealPlanItem.id != item_id,
        )
        .first()
    )

    if conflict:
        # Atomic swap via single SQL CASE statement — no intermediate
        # unique-constraint violations.
        db.execute(
            text(
                """
                UPDATE meal_plan_item
                SET day_of_week = CASE
                    WHEN id = :item_id THEN :new_day
                    WHEN id = :conflict_id THEN :old_day
                END,
                meal_type = CASE
                    WHEN id = :item_id THEN :new_type
                    WHEN id = :conflict_id THEN :old_type
                END
                WHERE id IN (:item_id, :conflict_id)
                """
            ),
            {
                "item_id": str(item_id),
                "conflict_id": str(conflict.id),
                "new_day": new_day_of_week,
                "new_type": new_meal_type,
                "old_day": item.day_of_week,
                "old_type": item.meal_type,
            },
        )
        db.commit()
        db.refresh(item)
        return {"message": "Meal swapped", "item": item}

    item.day_of_week = new_day_of_week
    item.meal_type = new_meal_type

    db.commit()
    db.refresh(item)
    return {"message": "Meal moved", "item": item}