use hir::{Problem, source_binder};
use ra_ide_api_light::Severity;
use ra_db::SourceDatabase;

use crate::{Diagnostic, FileId, FileSystemEdit, SourceChange, db::RootDatabase};

pub(crate) fn diagnostics(db: &RootDatabase, file_id: FileId) -> Vec<Diagnostic> {
    let syntax = db.parse(file_id);

    let mut res = ra_ide_api_light::diagnostics(&syntax)
        .into_iter()
        .map(|d| Diagnostic {
            range: d.range,
            message: d.msg,
            severity: d.severity,
            fix: d.fix.map(|fix| SourceChange::from_local_edit(file_id, fix)),
        })
        .collect::<Vec<_>>();
    if let Some(m) = source_binder::module_from_file_id(db, file_id) {
        for (name_node, problem) in m.problems(db) {
            let source_root = db.file_source_root(file_id);
            let diag = match problem {
                Problem::UnresolvedModule { candidate } => {
                    let create_file =
                        FileSystemEdit::CreateFile { source_root, path: candidate.clone() };
                    let fix = SourceChange {
                        label: "create module".to_string(),
                        source_file_edits: Vec::new(),
                        file_system_edits: vec![create_file],
                        cursor_position: None,
                    };
                    Diagnostic {
                        range: name_node.range(),
                        message: "unresolved module".to_string(),
                        severity: Severity::Error,
                        fix: Some(fix),
                    }
                }
                Problem::NotDirOwner { move_to, candidate } => {
                    let move_file = FileSystemEdit::MoveFile {
                        src: file_id,
                        dst_source_root: source_root,
                        dst_path: move_to.clone(),
                    };
                    let create_file =
                        FileSystemEdit::CreateFile { source_root, path: move_to.join(candidate) };
                    let fix = SourceChange {
                        label: "move file and create module".to_string(),
                        source_file_edits: Vec::new(),
                        file_system_edits: vec![move_file, create_file],
                        cursor_position: None,
                    };
                    Diagnostic {
                        range: name_node.range(),
                        message: "can't declare module at this location".to_string(),
                        severity: Severity::Error,
                        fix: Some(fix),
                    }
                }
            };
            res.push(diag)
        }
    };
    res
}