# app/api/schedule.py
"""
User schedule management endpoints.
Allows users to set their daily availability for study time.

Endpoints:
  GET  /api/schedule   — get current schedule
  POST /api/schedule   — save/update schedule
"""

import logging
from typing import Dict, List

from fastapi import APIRouter, Depends
from pydantic import BaseModel, Field, field_validator
from sqlalchemy.orm import Session

from app.core.database import get_db
from app.core.security import get_current_user
from app.models.user import User

logger = logging.getLogger("hale.api.schedule")
router = APIRouter(prefix="/api", tags=["Schedule"])


# ── Schemas ────────────────────────────────────────────────────────────────

class TimeBlock(BaseModel):
    start: str = Field(..., description="Start time in HH:MM format")
    end: str   = Field(..., description="End time in HH:MM format")
    label: str = Field("Study", description="Label for this block (Study, Exercise, etc.)")

    @field_validator("start", "end")
    @classmethod
    def validate_time(cls, v: str) -> str:
        import re
        if not re.match(r"^\d{2}:\d{2}$", v):
            raise ValueError("Time must be in HH:MM format")
        h, m = map(int, v.split(":"))
        if not (0 <= h <= 23 and 0 <= m <= 59):
            raise ValueError("Invalid time value")
        return v


class ScheduleRequest(BaseModel):
    lifestyle: str = Field(
        "student",
        description="Lifestyle type: student, job, college, freelancer, custom"
    )
    sleep_time: str = Field("23:00", description="Bedtime in HH:MM")
    wake_time:  str = Field("07:00", description="Wake-up time in HH:MM")
    blocks: Dict[str, List[TimeBlock]] = Field(
        default_factory=dict,
        description="Available blocks per weekday: {'monday': [{start, end, label}], ...}"
    )

    @field_validator("lifestyle")
    @classmethod
    def validate_lifestyle(cls, v: str) -> str:
        valid = {"student", "job", "college", "freelancer", "custom"}
        if v not in valid:
            raise ValueError(f"lifestyle must be one of: {', '.join(valid)}")
        return v


# ── Preset templates per lifestyle ────────────────────────────────────────

LIFESTYLE_PRESETS: Dict[str, Dict] = {
    "student": {
        "blocks": {
            "monday":    [{"start": "18:00", "end": "20:30", "label": "Study"}],
            "tuesday":   [{"start": "18:00", "end": "20:30", "label": "Study"}],
            "wednesday": [{"start": "18:00", "end": "20:30", "label": "Study"}],
            "thursday":  [{"start": "18:00", "end": "20:30", "label": "Study"}],
            "friday":    [{"start": "17:00", "end": "19:30", "label": "Study"}],
            "saturday":  [{"start": "10:00", "end": "13:00", "label": "Study"}],
            "sunday":    [{"start": "10:00", "end": "12:00", "label": "Study"}],
        }
    },
    "job": {
        "blocks": {
            "monday":    [{"start": "07:00", "end": "08:00", "label": "Study"}, {"start": "21:00", "end": "22:30", "label": "Study"}],
            "tuesday":   [{"start": "07:00", "end": "08:00", "label": "Study"}, {"start": "21:00", "end": "22:30", "label": "Study"}],
            "wednesday": [{"start": "07:00", "end": "08:00", "label": "Study"}, {"start": "21:00", "end": "22:30", "label": "Study"}],
            "thursday":  [{"start": "07:00", "end": "08:00", "label": "Study"}, {"start": "21:00", "end": "22:30", "label": "Study"}],
            "friday":    [{"start": "21:00", "end": "22:30", "label": "Study"}],
            "saturday":  [{"start": "09:00", "end": "12:00", "label": "Study"}],
            "sunday":    [{"start": "10:00", "end": "12:00", "label": "Study"}],
        }
    },
    "college": {
        "blocks": {
            "monday":    [{"start": "16:00", "end": "19:00", "label": "Study"}],
            "tuesday":   [{"start": "16:00", "end": "19:00", "label": "Study"}],
            "wednesday": [{"start": "16:00", "end": "19:00", "label": "Study"}],
            "thursday":  [{"start": "16:00", "end": "19:00", "label": "Study"}],
            "friday":    [{"start": "15:00", "end": "18:00", "label": "Study"}],
            "saturday":  [{"start": "10:00", "end": "14:00", "label": "Study"}],
            "sunday":    [{"start": "11:00", "end": "14:00", "label": "Study"}],
        }
    },
    "freelancer": {
        "blocks": {
            "monday":    [{"start": "09:00", "end": "11:00", "label": "Study"}],
            "tuesday":   [{"start": "09:00", "end": "11:00", "label": "Study"}],
            "wednesday": [{"start": "09:00", "end": "11:00", "label": "Study"}],
            "thursday":  [{"start": "09:00", "end": "11:00", "label": "Study"}],
            "friday":    [{"start": "09:00", "end": "11:00", "label": "Study"}],
            "saturday":  [{"start": "10:00", "end": "13:00", "label": "Study"}],
            "sunday":    [{"start": "10:00", "end": "12:00", "label": "Study"}],
        }
    },
}


def _compute_daily_minutes(blocks_dict: Dict) -> Dict[str, int]:
    """Compute total study minutes per day."""
    result = {}
    for day, blocks in blocks_dict.items():
        total = 0
        for b in blocks:
            try:
                sh, sm = map(int, b["start"].split(":"))
                eh, em = map(int, b["end"].split(":"))
                total += (eh * 60 + em) - (sh * 60 + sm)
            except Exception:
                pass
        result[day] = max(0, total)
    return result


# ── Endpoints ──────────────────────────────────────────────────────────────

@router.get("/schedule", summary="Get user's current schedule")
def get_schedule(
    current_user: User = Depends(get_current_user),
    db: Session = Depends(get_db),
):
    schedule = current_user.schedule_json or {}
    if not schedule:
        # Return default student preset
        preset = LIFESTYLE_PRESETS["student"].copy()
        preset["lifestyle"] = "student"
        preset["sleep_time"] = "23:00"
        preset["wake_time"] = "07:00"
        preset["daily_minutes"] = _compute_daily_minutes(preset["blocks"])
        return {"schedule": preset, "is_default": True}

    daily_mins = _compute_daily_minutes(schedule.get("blocks", {}))
    return {"schedule": {**schedule, "daily_minutes": daily_mins}, "is_default": False}


@router.post("/schedule", summary="Save user's study schedule")
def save_schedule(
    payload: ScheduleRequest,
    current_user: User = Depends(get_current_user),
    db: Session = Depends(get_db),
):
    # Apply preset as base if blocks were not explicitly provided
    if "blocks" not in payload.model_fields_set and payload.lifestyle in LIFESTYLE_PRESETS:
        blocks = LIFESTYLE_PRESETS[payload.lifestyle]["blocks"]
    else:
        blocks = {day: [b.model_dump() for b in block_list] for day, block_list in payload.blocks.items()}

    schedule_data = {
        "lifestyle": payload.lifestyle,
        "sleep_time": payload.sleep_time,
        "wake_time":  payload.wake_time,
        "blocks":     blocks,
    }

    current_user.schedule_json = schedule_data
    db.commit()

    daily_mins = _compute_daily_minutes(blocks)
    logger.info("Schedule saved for %s: %s (%d days configured)", current_user.user_id, payload.lifestyle, len(blocks))

    return {
        "message":       "Schedule saved!",
        "schedule":      {**schedule_data, "daily_minutes": daily_mins},
        "avg_daily_min": sum(daily_mins.values()) // max(len(daily_mins), 1),
    }


@router.get("/schedule/presets", summary="Get lifestyle schedule presets")
def get_presets():
    result = {}
    for lifestyle, data in LIFESTYLE_PRESETS.items():
        daily_mins = _compute_daily_minutes(data["blocks"])
        result[lifestyle] = {
            "blocks": data["blocks"],
            "daily_minutes": daily_mins,
            "avg_daily_min": sum(daily_mins.values()) // 7,
        }
    return {"presets": result}