2 files changed, 195 insertions, 32 deletions

diff --git a/crates/libanalysis/src/api.rs b/crates/libanalysis/src/api.rs
new file mode 100644
index 000000000..bb4fee398
--- /dev/null
+++ b/crates/libanalysis/src/api.rs
@@ -0,0 +1,136 @@
+use relative_path::RelativePathBuf;
+use libsyntax2::{File, TextRange, TextUnit, AtomEdit};
+use libeditor;
+use {World, FileId, Query};
+
+pub use libeditor::{
+    LocalEdit, StructureNode, LineIndex, FileSymbol,
+    Runnable, RunnableKind, HighlightedRange, CompletionItem
+};
+
+#[derive(Clone, Debug)]
+pub struct Analysis {
+    pub(crate) imp: World
+}
+
+impl Analysis {
+    pub fn file_syntax(&self, file_id: FileId) -> File {
+        self.imp.file_syntax(file_id)
+            .unwrap()
+    }
+    pub fn file_line_index(&self, file_id: FileId) -> LineIndex {
+        self.imp.file_line_index(file_id)
+            .unwrap()
+    }
+    pub fn extend_selection(&self, file: &File, range: TextRange) -> TextRange {
+        libeditor::extend_selection(file, range).unwrap_or(range)
+    }
+    pub fn matching_brace(&self, file: &File, offset: TextUnit) -> Option<TextUnit> {
+        libeditor::matching_brace(file, offset)
+    }
+    pub fn syntax_tree(&self, file_id: FileId) -> String {
+        let file = self.file_syntax(file_id);
+        libeditor::syntax_tree(&file)
+    }
+    pub fn join_lines(&self, file_id: FileId, range: TextRange) -> SourceChange {
+        let file = self.file_syntax(file_id);
+        SourceChange::from_local_edit(
+            file_id, "join lines",
+            libeditor::join_lines(&file, range),
+        )
+    }
+    pub fn on_eq_typed(&self, file_id: FileId, offset: TextUnit) -> Option<SourceChange> {
+        let file = self.file_syntax(file_id);
+        Some(SourceChange::from_local_edit(
+            file_id, "add semicolon",
+            libeditor::on_eq_typed(&file, offset)?,
+        ))
+    }
+    pub fn file_structure(&self, file_id: FileId) -> Vec<StructureNode> {
+        let file = self.file_syntax(file_id);
+        libeditor::file_structure(&file)
+    }
+    pub fn symbol_search(&self, query: Query) -> Vec<(FileId, FileSymbol)> {
+        self.imp.world_symbols(query)
+    }
+    pub fn approximately_resolve_symbol(&self, file_id: FileId, offset: TextUnit) -> Vec<(FileId, FileSymbol)> {
+        self.imp.approximately_resolve_symbol(file_id, offset)
+            .unwrap()
+    }
+    pub fn parent_module(&self, file_id: FileId) -> Vec<(FileId, FileSymbol)> {
+        self.imp.parent_module(file_id)
+    }
+    pub fn runnables(&self, file_id: FileId) -> Vec<Runnable> {
+        let file = self.file_syntax(file_id);
+        libeditor::runnables(&file)
+    }
+    pub fn highlight(&self, file_id: FileId) -> Vec<HighlightedRange> {
+        let file = self.file_syntax(file_id);
+        libeditor::highlight(&file)
+    }
+    pub fn completions(&self, file_id: FileId, offset: TextUnit) -> Option<Vec<CompletionItem>> {
+        let file = self.file_syntax(file_id);
+        libeditor::scope_completion(&file, offset)
+    }
+    pub fn assists(&self, file_id: FileId, offset: TextUnit) -> Vec<SourceChange> {
+        self.imp.assists(file_id, offset)
+    }
+    pub fn diagnostics(&self, file_id: FileId) -> Vec<Diagnostic> {
+        self.imp.diagnostics(file_id)
+    }
+}
+
+#[derive(Debug)]
+pub struct SourceChange {
+    pub label: String,
+    pub source_file_edits: Vec<SourceFileEdit>,
+    pub file_system_edits: Vec<FileSystemEdit>,
+    pub cursor_position: Option<Position>,
+}
+
+#[derive(Debug)]
+pub struct Position {
+    pub file_id: FileId,
+    pub offset: TextUnit,
+}
+
+#[derive(Debug)]
+pub struct SourceFileEdit {
+    pub file_id: FileId,
+    pub edits: Vec<AtomEdit>,
+}
+
+#[derive(Debug)]
+pub enum FileSystemEdit {
+    CreateFile {
+        anchor: FileId,
+        path: RelativePathBuf,
+    },
+    MoveFile {
+        file: FileId,
+        path: RelativePathBuf,
+    }
+}
+
+#[derive(Debug)]
+pub struct Diagnostic {
+    pub message: String,
+    pub range: TextRange,
+    pub fix: Option<SourceChange>,
+}
+
+impl SourceChange {
+    pub(crate) fn from_local_edit(file_id: FileId, label: &str, edit: LocalEdit) -> SourceChange {
+        let file_edit = SourceFileEdit {
+            file_id,
+            edits: edit.edit.into_atoms(),
+        };
+        SourceChange {
+            label: label.to_string(),
+            source_file_edits: vec![file_edit],
+            file_system_edits: vec![],
+            cursor_position: edit.cursor_position
+                .map(|offset| Position { offset, file_id })
+        }
+    }
+}
diff --git a/crates/libanalysis/src/lib.rs b/crates/libanalysis/src/lib.rs
index 96d10a087..ec20d106f 100644
--- a/crates/libanalysis/src/lib.rs
+++ b/crates/libanalysis/src/lib.rs
@@ -12,6 +12,7 @@ extern crate relative_path;
 
 mod symbol_index;
 mod module_map;
+mod api;
 
 use std::{
     fmt,
@@ -34,13 +35,14 @@ use libsyntax2::{
     ast::{self, AstNode, NameOwner},
     SyntaxKind::*,
 };
-use libeditor::{Diagnostic, LineIndex, FileSymbol, find_node_at_offset};
+use libeditor::{LineIndex, FileSymbol, find_node_at_offset};
 
 use self::{
     symbol_index::FileSymbols,
     module_map::{ModuleMap, ChangeKind, Problem},
 };
 pub use self::symbol_index::Query;
+pub use self::api::*;
 
 pub type Result<T> = ::std::result::Result<T, ::failure::Error>;
 
@@ -97,6 +99,13 @@ impl WorldState {
         }
     }
 
+    pub fn analysis(
+        &self,
+        file_resolver: impl FileResolver,
+    ) -> Analysis {
+        Analysis { imp: self.snapshot(file_resolver) }
+    }
+
     pub fn change_file(&mut self, file_id: FileId, text: Option<String>) {
         self.change_files(::std::iter::once((file_id, text)));
     }
@@ -231,11 +240,11 @@ impl World {
         Ok(vec![])
     }
 
-    pub fn diagnostics(&self, file_id: FileId) -> Result<Vec<(Diagnostic, Option<QuickFix>)>> {
-        let syntax = self.file_syntax(file_id)?;
+    pub fn diagnostics(&self, file_id: FileId) -> Vec<Diagnostic> {
+        let syntax = self.file_syntax(file_id).unwrap();
         let mut res = libeditor::diagnostics(&syntax)
             .into_iter()
-            .map(|d| (d, None))
+            .map(|d| Diagnostic { range: d.range, message: d.msg, fix: None })
             .collect::<Vec<_>>();
 
         self.data.module_map.problems(
@@ -243,44 +252,62 @@ impl World {
             &*self.file_resolver,
             &|file_id| self.file_syntax(file_id).unwrap(),
             |name_node, problem| {
-                let (diag, fix) = match problem {
+                let diag = match problem {
                     Problem::UnresolvedModule { candidate } => {
-                        let diag = Diagnostic {
-                            range: name_node.syntax().range(),
-                            msg: "unresolved module".to_string(),
+                        let create_file = FileSystemEdit::CreateFile {
+                            anchor: file_id,
+                            path: candidate.clone(),
                         };
-                        let fix = QuickFix {
-                            fs_ops: vec![FsOp::CreateFile {
-                                anchor: file_id,
-                                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,
                         };
-                        (diag, fix)
+                        Diagnostic {
+                            range: name_node.syntax().range(),
+                            message: "unresolved module".to_string(),
+                            fix: Some(fix),
+                        }
                     }
                     Problem::NotDirOwner { move_to, candidate } => {
-                        let diag = Diagnostic {
-                            range: name_node.syntax().range(),
-                            msg: "can't declare module at this location".to_string(),
+                        let move_file = FileSystemEdit::MoveFile { file: file_id, path: move_to.clone() };
+                        let create_file = FileSystemEdit::CreateFile { anchor: file_id, 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,
                         };
-                        let fix = QuickFix {
-                            fs_ops: vec![
-                                FsOp::MoveFile {
-                                    file: file_id,
-                                    path: move_to.clone(),
-                                },
-                                FsOp::CreateFile {
-                                    anchor: file_id,
-                                    path: move_to.join(candidate),
-                                }
-                            ],
-                        };
-                        (diag, fix)
+                        Diagnostic {
+                            range: name_node.syntax().range(),
+                            message: "can't declare module at this location".to_string(),
+                            fix: Some(fix),
+                        }
                     }
                 };
-                res.push((diag, Some(fix)))
+                res.push(diag)
             }
         );
-        Ok(res)
+        res
+    }
+
+    pub fn assists(&self, file_id: FileId, offset: TextUnit) -> Vec<SourceChange> {
+        let file = self.file_syntax(file_id).unwrap();
+        let actions = vec![
+            ("flip comma", libeditor::flip_comma(&file, offset).map(|f| f())),
+            ("add `#[derive]`", libeditor::add_derive(&file, offset).map(|f| f())),
+            ("add impl", libeditor::add_impl(&file, offset).map(|f| f())),
+        ];
+        let mut res = Vec::new();
+        for (name, local_edit) in actions {
+            if let Some(local_edit) = local_edit {
+                res.push(SourceChange::from_local_edit(
+                    file_id, name, local_edit
+                ))
+            }
+        }
+        res
     }
 
     fn index_resolve(&self, name_ref: ast::NameRef) -> Vec<(FileId, FileSymbol)> {