use rustpython_parser::ast::{Expr, ExprKind, Stmt, StmtKind};

use ruff_diagnostics::{Diagnostic, Violation};
use ruff_macros::{derive_message_formats, violation};
use ruff_python_ast::types::Range;

use crate::checkers::ast::Checker;
use crate::rules::flake8_django::rules::helpers::is_model_form;

/// ## What it does
/// Checks for the use of `exclude` in Django `ModelForm` classes.
///
/// ## Why is this bad?
/// If a `ModelForm` includes the `exclude` attribute, any new field that
/// is added to the model will automatically be exposed for modification.
///
/// ## Example
/// ```python
/// from django.forms import ModelForm
///
/// class PostForm(ModelForm):
///     class Meta:
///         model = Post
///         exclude = ["author"]
/// ```
///
/// Use instead:
/// ```python
/// from django.forms import ModelForm
///
/// class PostForm(ModelForm):
///     class Meta:
///         model = Post
///         fields = ["title", "content"]
/// ```
#[violation]
pub struct ExcludeWithModelForm;

impl Violation for ExcludeWithModelForm {
    #[derive_message_formats]
    fn message(&self) -> String {
        format!("Do not use `exclude` with `ModelForm`, use `fields` instead")
    }
}

/// DJ006
pub fn exclude_with_model_form(
    checker: &Checker,
    bases: &[Expr],
    body: &[Stmt],
) -> Option<Diagnostic> {
    if !bases.iter().any(|base| is_model_form(checker, base)) {
        return None;
    }
    for element in body.iter() {
        let StmtKind::ClassDef { name, body, .. } = &element.node else {
            continue;
        };
        if name != "Meta" {
            continue;
        }
        for element in body.iter() {
            let StmtKind::Assign { targets, .. } = &element.node else {
                continue;
            };
            for target in targets.iter() {
                let ExprKind::Name { id, .. } = &target.node else {
                    continue;
                };
                if id == "exclude" {
                    return Some(Diagnostic::new(ExcludeWithModelForm, Range::from(target)));
                }
            }
        }
    }
    None
}
