"""Settings endpoints."""

import json
from typing import Any
from fastapi import APIRouter, Depends, HTTPException, status
from sqlalchemy.orm import Session

from app import crud, schemas
from app.dependencies import get_db, get_current_superuser, get_current_user
from app.models.user import User
from app.core.settings_registry import (
    THEME_KEYS,
    MODULE_KEYS,
    UI_KEYS,
    SETTINGS_REGISTRY,
    SettingStorage,
    SettingType,
    get_default_value,
)


router = APIRouter()


def _require_database_setting(key: str):
    setting_def = SETTINGS_REGISTRY.get(key)
    if not setting_def:
        raise HTTPException(
            status_code=status.HTTP_400_BAD_REQUEST,
            detail=f"Unknown setting key '{key}'"
        )
    if setting_def.storage != SettingStorage.DATABASE:
        raise HTTPException(
            status_code=status.HTTP_400_BAD_REQUEST,
            detail=f"Setting '{key}' is not stored in database"
        )
    return setting_def


def _coerce_setting_value(key: str, value: Any) -> Any:
    setting_def = _require_database_setting(key)

    if setting_def.type == SettingType.BOOLEAN:
        if isinstance(value, bool):
            coerced = value
        elif isinstance(value, int) and not isinstance(value, bool):
            if value in (0, 1):
                coerced = bool(value)
            else:
                raise HTTPException(status_code=400, detail=f"Invalid boolean value for '{key}'")
        elif isinstance(value, str):
            lowered = value.strip().lower()
            if lowered in ("true", "1"):
                coerced = True
            elif lowered in ("false", "0"):
                coerced = False
            else:
                raise HTTPException(status_code=400, detail=f"Invalid boolean value for '{key}'")
        else:
            raise HTTPException(status_code=400, detail=f"Invalid boolean value for '{key}'")

    elif setting_def.type == SettingType.INTEGER:
        if isinstance(value, bool):
            raise HTTPException(status_code=400, detail=f"Invalid integer value for '{key}'")
        if isinstance(value, int):
            coerced = value
        elif isinstance(value, str):
            try:
                coerced = int(value.strip())
            except ValueError as exc:
                raise HTTPException(status_code=400, detail=f"Invalid integer value for '{key}'") from exc
        else:
            raise HTTPException(status_code=400, detail=f"Invalid integer value for '{key}'")

    elif setting_def.type == SettingType.STRING:
        if not isinstance(value, str):
            raise HTTPException(status_code=400, detail=f"Invalid string value for '{key}'")
        coerced = value

    elif setting_def.type == SettingType.JSON:
        if isinstance(value, (dict, list)):
            coerced = value
        elif isinstance(value, str):
            try:
                coerced = json.loads(value)
            except json.JSONDecodeError as exc:
                raise HTTPException(status_code=400, detail=f"Invalid JSON value for '{key}'") from exc
        else:
            raise HTTPException(status_code=400, detail=f"Invalid JSON value for '{key}'")

    elif setting_def.type == SettingType.LIST:
        if isinstance(value, list):
            coerced = value
        elif isinstance(value, str):
            try:
                parsed = json.loads(value)
            except json.JSONDecodeError as exc:
                raise HTTPException(status_code=400, detail=f"Invalid list value for '{key}'") from exc
            if not isinstance(parsed, list):
                raise HTTPException(status_code=400, detail=f"Invalid list value for '{key}'")
            coerced = parsed
        else:
            raise HTTPException(status_code=400, detail=f"Invalid list value for '{key}'")

    else:
        coerced = value

    if setting_def.choices is not None and coerced not in setting_def.choices:
        raise HTTPException(
            status_code=status.HTTP_400_BAD_REQUEST,
            detail=f"Invalid value for '{key}'. Allowed: {setting_def.choices}"
        )

    return coerced


def _validate_bulk_keys(payload: dict[str, Any], allowed_keys: set[str]) -> None:
    unknown = [key for key in payload.keys() if key not in allowed_keys]
    if unknown:
        raise HTTPException(
            status_code=status.HTTP_400_BAD_REQUEST,
            detail=f"Unknown/unsupported keys: {sorted(unknown)}"
        )


@router.get("/theme", response_model=dict[str, Any])
def get_theme_settings(
    *,
    db: Session = Depends(get_db),
    current_user: User = Depends(get_current_user)
) -> Any:
    """
    Get theme settings (accessible to all authenticated users).

    Returns theme-related settings that apply to all users.
    """
    result = {}
    for key in THEME_KEYS:
        setting = crud.settings.get_setting(db, key=key)
        if setting:
            result[key] = setting.get_value()
        else:
            # Use default from registry
            result[key] = get_default_value(key)
    return result


@router.get("/theme/public", response_model=dict[str, Any])
def get_theme_settings_public(
    *,
    db: Session = Depends(get_db),
) -> Any:
    """
    Get theme settings without authentication.

    Intended for login/landing pages to keep UI consistent before auth.
    """
    result = {}
    for key in THEME_KEYS:
        setting = crud.settings.get_setting(db, key=key)
        if setting:
            result[key] = setting.get_value()
        else:
            result[key] = get_default_value(key)
    return result


@router.put("/theme", response_model=dict[str, Any])
def update_theme_settings(
    *,
    db: Session = Depends(get_db),
    theme_data: dict[str, Any],
    current_user: User = Depends(get_current_superuser)
) -> Any:
    """
    Update theme settings (admin only).

    Updates multiple theme settings at once.
    """
    _validate_bulk_keys(theme_data, set(THEME_KEYS))
    result = {}
    for key, value in theme_data.items():
        coerced = _coerce_setting_value(key, value)
        setting = crud.settings.update_setting(db, key=key, value=coerced)
        result[key] = setting.get_value()
    return result


@router.get("/modules", response_model=dict[str, Any])
def get_module_settings(
    *,
    db: Session = Depends(get_db),
    current_user: User = Depends(get_current_user)
) -> Any:
    """
    Get module settings (accessible to all authenticated users).

    Returns module enabled/disabled states.
    """
    result = {}
    for key in MODULE_KEYS:
        setting = crud.settings.get_setting(db, key=key)
        if setting:
            result[key] = setting.get_value()
        else:
            # Use default from registry
            result[key] = get_default_value(key)
    return result


@router.get("/ui", response_model=dict[str, Any])
def get_ui_settings(
    *,
    db: Session = Depends(get_db),
    current_user: User = Depends(get_current_user)
) -> Any:
    """
    Get UI settings (accessible to all authenticated users).

    Returns UI/layout settings that apply to all users.
    """
    result = {}
    for key in UI_KEYS:
        setting = crud.settings.get_setting(db, key=key)
        if setting:
            result[key] = setting.get_value()
        else:
            result[key] = get_default_value(key)
    return result


@router.put("/ui", response_model=dict[str, Any])
def update_ui_settings(
    *,
    db: Session = Depends(get_db),
    ui_data: dict[str, Any],
    current_user: User = Depends(get_current_superuser)
) -> Any:
    """
    Update UI settings (admin only).

    Updates multiple UI/layout settings at once.
    """
    _validate_bulk_keys(ui_data, set(UI_KEYS))
    result = {}
    for key, value in ui_data.items():
        coerced = _coerce_setting_value(key, value)
        setting = crud.settings.update_setting(db, key=key, value=coerced)
        result[key] = setting.get_value()
    return result


@router.put("/modules", response_model=dict[str, Any])
def update_module_settings(
    *,
    db: Session = Depends(get_db),
    module_data: dict[str, Any],
    current_user: User = Depends(get_current_superuser)
) -> Any:
    """
    Update module settings (admin only).

    Enable or disable modules for all users.
    """
    _validate_bulk_keys(module_data, set(MODULE_KEYS))
    result = {}
    for key, value in module_data.items():
        coerced = _coerce_setting_value(key, value)
        setting = crud.settings.update_setting(db, key=key, value=coerced)
        result[key] = setting.get_value()
    return result


@router.get("/user_mode_enabled", response_model=dict[str, Any])
def get_user_mode_enabled(
    *,
    db: Session = Depends(get_db),
    current_user: User = Depends(get_current_user)
) -> Any:
    """
    Get user mode enabled setting (accessible to all authenticated users).
    """
    setting = crud.settings.get_setting(db, key="user_mode_enabled")
    if setting:
        return {"key": "user_mode_enabled", "value": setting.get_value()}
    # Use default from registry
    return {"key": "user_mode_enabled", "value": get_default_value("user_mode_enabled")}


@router.put("/user_mode_enabled", response_model=dict[str, Any])
def update_user_mode_enabled(
    *,
    db: Session = Depends(get_db),
    data: dict[str, Any],
    current_user: User = Depends(get_current_superuser)
) -> Any:
    """
    Update user mode enabled setting (admin only).
    """
    value = data.get("value", True)
    coerced = _coerce_setting_value("user_mode_enabled", value)
    setting = crud.settings.update_setting(db, key="user_mode_enabled", value=coerced)
    return {"key": "user_mode_enabled", "value": setting.get_value()}


@router.get("", response_model=dict[str, Any])
def get_all_settings(
    *,
    db: Session = Depends(get_db),
    current_user: User = Depends(get_current_superuser)
) -> Any:
    """
    Get all settings (admin only).

    Returns all application settings as a dictionary.
    """
    settings_list = crud.settings.get_all_settings(db)
    return {s.key: s.get_value() for s in settings_list}


@router.get("/{key}", response_model=schemas.Setting)
def get_setting(
    *,
    db: Session = Depends(get_db),
    key: str,
    current_user: User = Depends(get_current_superuser)
) -> Any:
    """
    Get a specific setting by key (admin only).
    """
    setting = crud.settings.get_setting(db, key=key)
    if not setting:
        raise HTTPException(
            status_code=status.HTTP_404_NOT_FOUND,
            detail=f"Setting '{key}' not found"
        )
    return schemas.Setting.from_orm(setting)


@router.put("/{key}", response_model=schemas.Setting)
def update_setting(
    *,
    db: Session = Depends(get_db),
    key: str,
    setting_in: schemas.SettingUpdate,
    current_user: User = Depends(get_current_superuser)
) -> Any:
    """
    Update a setting (admin only).
    
    Creates the setting if it doesn't exist.
    """
    coerced = _coerce_setting_value(key, setting_in.value)
    setting = crud.settings.update_setting(db, key=key, value=coerced)
    return schemas.Setting.from_orm(setting)