"""Service for seeding the database from YAML config files.

Reads config/exercises.yaml and config/user_programs.yaml to populate
the exercise library, warmups, workout days, and user programs.
"""

from pathlib import Path
from typing import Optional

import structlog
import yaml
from sqlmodel import Session, select

from app.models.exercise import Exercise
from app.models.user import User
from app.models.user_exercise_program import UserExerciseProgram
from app.models.warmup import Warmup
from app.models.workout_day import WorkoutDay

logger = structlog.get_logger(__name__)

# Default workout day definitions
WORKOUT_DAYS = [
    {"name": "Push", "day_number": 1, "description": "Chest, shoulders, triceps"},
    {"name": "Pull", "day_number": 2, "description": "Back, biceps, traps"},
    {"name": "Lower", "day_number": 3, "description": "Quads, hamstrings, glutes, calves"},
    {"name": "Full Body", "day_number": 4, "description": "Compound full-body movements"},
]


class SeedService:
    """Seeds the database from YAML configuration files.

    Args:
        session: An active SQLModel Session.
        config_dir: Path to the config directory containing YAML files.
    """

    def __init__(self, session: Session, config_dir: Optional[Path] = None) -> None:
        self._session = session
        self._config_dir = config_dir or Path(__file__).resolve().parent.parent.parent / "config"

    def _load_yaml(self, filename: str) -> dict:
        """Load and parse a YAML file from the config directory."""
        filepath = self._config_dir / filename
        with open(filepath, "r") as f:
            return yaml.safe_load(f)

    def seed_workout_days(self) -> None:
        """Seed the 4 workout day records if they don't already exist."""
        existing = self._session.exec(select(WorkoutDay)).first()
        if existing:
            logger.info("seed_skipped", table="workout_days", reason="already seeded")
            return

        for day_data in WORKOUT_DAYS:
            day = WorkoutDay(**day_data)
            self._session.add(day)
        self._session.commit()
        logger.info("seed_complete", table="workout_days", count=len(WORKOUT_DAYS))

    def seed_exercises(self) -> None:
        """Seed exercises from config/exercises.yaml if table is empty."""
        existing = self._session.exec(select(Exercise)).first()
        if existing:
            logger.info("seed_skipped", table="exercises", reason="already seeded")
            return

        data = self._load_yaml("exercises.yaml")
        exercises = data.get("exercises", [])
        for ex in exercises:
            exercise = Exercise(
                name=ex["name"],
                muscle_group=ex["muscle_group"],
                workout_day=ex["workout_day"],
                sets=ex.get("sets", 3),
                tempo=ex.get("tempo", ""),
                form_cues=ex.get("form_cues", "").strip(),
            )
            self._session.add(exercise)
        self._session.commit()
        logger.info("seed_complete", table="exercises", count=len(exercises))

    def seed_warmups(self) -> None:
        """Seed warmups from config/exercises.yaml if table is empty."""
        existing = self._session.exec(select(Warmup)).first()
        if existing:
            logger.info("seed_skipped", table="warmups", reason="already seeded")
            return

        data = self._load_yaml("exercises.yaml")
        warmups = data.get("warmup", [])
        for i, wu in enumerate(warmups, start=1):
            warmup = Warmup(
                name=wu["name"],
                type=wu.get("type", ""),
                reps=wu.get("reps", ""),
                form_cues=wu.get("form_cues", "").strip(),
                sort_order=i,
            )
            self._session.add(warmup)
        self._session.commit()
        logger.info("seed_complete", table="warmups", count=len(warmups))

    def seed_user_programs(self) -> None:
        """Seed user profiles and their exercise programs from user_programs.yaml."""
        data = self._load_yaml("user_programs.yaml")
        programs = data.get("programs", [])

        for program in programs:
            username = program["user"].lower().replace(" ", "_")
            display_name = program["user"]
            profile = program.get("profile", {})

            # Check if user already exists
            existing_user = self._session.exec(
                select(User).where(User.username == username)
            ).first()

            if existing_user:
                user = existing_user
                logger.info("seed_skipped", table="users", user=username, reason="already exists")
            else:
                user = User(
                    username=username,
                    display_name=display_name,
                    height=profile.get("height", ""),
                    weight=profile.get("weight", ""),
                    goals=profile.get("goals", ""),
                )
                self._session.add(user)
                self._session.commit()
                self._session.refresh(user)
                logger.info("seed_complete", table="users", user=username)

            # Link exercises to user
            for ex_data in program.get("exercises", []):
                exercise = self._session.exec(
                    select(Exercise).where(Exercise.name == ex_data["name"])
                ).first()

                if exercise is None:
                    logger.warning("seed_exercise_not_found", name=ex_data["name"])
                    continue

                # Check if program already exists
                existing_program = self._session.exec(
                    select(UserExerciseProgram).where(
                        UserExerciseProgram.user_id == user.id,
                        UserExerciseProgram.exercise_id == exercise.id,
                    )
                ).first()

                if existing_program:
                    continue

                uep = UserExerciseProgram(
                    user_id=user.id,
                    exercise_id=exercise.id,
                    wk1_reps=str(ex_data.get("wk1_reps", "")),
                    wk4_reps=str(ex_data.get("wk4_reps", "")),
                    wk1_weight=str(ex_data.get("wk1_weight", "")),
                    wk4_weight=str(ex_data.get("wk4_weight", "")),
                )
                self._session.add(uep)

            self._session.commit()
            logger.info("seed_complete", table="user_exercise_programs", user=username)

    def seed_all(self) -> None:
        """Run all seed operations in the correct order."""
        logger.info("seed_all_started")
        self.seed_workout_days()
        self.seed_exercises()
        self.seed_warmups()
        self.seed_user_programs()
        logger.info("seed_all_complete")