1 files changed, 202 insertions, 0 deletions
diff --git a/src/debputy/lsp/quickfixes.py b/src/debputy/lsp/quickfixes.py
new file mode 100644
index 0000000..d911961
--- /dev/null
+++ b/src/debputy/lsp/quickfixes.py
@@ -0,0 +1,202 @@
+from typing import (
+    Literal,
+    TypedDict,
+    Callable,
+    Iterable,
+    Union,
+    TypeVar,
+    Mapping,
+    Dict,
+    Optional,
+    List,
+    cast,
+)
+
+from lsprotocol.types import (
+    CodeAction,
+    Command,
+    CodeActionParams,
+    Diagnostic,
+    CodeActionDisabledType,
+    TextEdit,
+    WorkspaceEdit,
+    TextDocumentEdit,
+    OptionalVersionedTextDocumentIdentifier,
+    Range,
+    Position,
+    CodeActionKind,
+)
+
+from debputy.util import _warn
+
+try:
+    from debian._deb822_repro.locatable import Position as TEPosition, Range as TERange
+
+    from pygls.server import LanguageServer
+    from pygls.workspace import TextDocument
+except ImportError:
+    pass
+
+
+CodeActionName = Literal["correct-text", "remove-line"]
+
+
+class CorrectTextCodeAction(TypedDict):
+    code_action: Literal["correct-text"]
+    correct_value: str
+
+
+class RemoveLineCodeAction(TypedDict):
+    code_action: Literal["remove-line"]
+
+
+def propose_correct_text_quick_fix(correct_value: str) -> CorrectTextCodeAction:
+    return {
+        "code_action": "correct-text",
+        "correct_value": correct_value,
+    }
+
+
+def propose_remove_line_quick_fix() -> RemoveLineCodeAction:
+    return {
+        "code_action": "remove-line",
+    }
+
+
+CODE_ACTION_HANDLERS: Dict[
+    CodeActionName,
+    Callable[
+        [Mapping[str, str], CodeActionParams, Diagnostic],
+        Iterable[Union[CodeAction, Command]],
+    ],
+] = {}
+M = TypeVar("M", bound=Mapping[str, str])
+Handler = Callable[
+    [M, CodeActionParams, Diagnostic],
+    Iterable[Union[CodeAction, Command]],
+]
+
+
+def _code_handler_for(action_name: CodeActionName) -> Callable[[Handler], Handler]:
+    def _wrapper(func: Handler) -> Handler:
+        assert action_name not in CODE_ACTION_HANDLERS
+        CODE_ACTION_HANDLERS[action_name] = func
+        return func
+
+    return _wrapper
+
+
+@_code_handler_for("correct-text")
+def _correct_value_code_action(
+    code_action_data: CorrectTextCodeAction,
+    code_action_params: CodeActionParams,
+    diagnostic: Diagnostic,
+) -> Iterable[Union[CodeAction, Command]]:
+    corrected_value = code_action_data["correct_value"]
+    edits = [
+        TextEdit(
+            diagnostic.range,
+            corrected_value,
+        ),
+    ]
+    yield CodeAction(
+        title=f'Replace with "{corrected_value}"',
+        kind=CodeActionKind.QuickFix,
+        diagnostics=[diagnostic],
+        edit=WorkspaceEdit(
+            changes={code_action_params.text_document.uri: edits},
+            document_changes=[
+                TextDocumentEdit(
+                    text_document=OptionalVersionedTextDocumentIdentifier(
+                        uri=code_action_params.text_document.uri,
+                    ),
+                    edits=edits,
+                )
+            ],
+        ),
+    )
+
+
+def range_compatible_with_remove_line_fix(range_: Range) -> bool:
+    start = range_.start
+    end = range_.end
+    if start.line != end.line and (start.line + 1 != end.line or end.character > 0):
+        return False
+    return True
+
+
+@_code_handler_for("remove-line")
+def _correct_value_code_action(
+    _code_action_data: RemoveLineCodeAction,
+    code_action_params: CodeActionParams,
+    diagnostic: Diagnostic,
+) -> Iterable[Union[CodeAction, Command]]:
+    start = code_action_params.range.start
+    if range_compatible_with_remove_line_fix(code_action_params.range):
+        _warn(
+            "Bug: the quick was used for a diagnostic that spanned multiple lines and would corrupt the file."
+        )
+        return
+
+    edits = [
+        TextEdit(
+            Range(
+                start=Position(
+                    line=start.line,
+                    character=0,
+                ),
+                end=Position(
+                    line=start.line + 1,
+                    character=0,
+                ),
+            ),
+            "",
+        ),
+    ]
+    yield CodeAction(
+        title="Remove the line",
+        kind=CodeActionKind.QuickFix,
+        diagnostics=[diagnostic],
+        edit=WorkspaceEdit(
+            changes={code_action_params.text_document.uri: edits},
+            document_changes=[
+                TextDocumentEdit(
+                    text_document=OptionalVersionedTextDocumentIdentifier(
+                        uri=code_action_params.text_document.uri,
+                    ),
+                    edits=edits,
+                )
+            ],
+        ),
+    )
+
+
+def provide_standard_quickfixes_from_diagnostics(
+    code_action_params: CodeActionParams,
+) -> Optional[List[Union[Command, CodeAction]]]:
+    actions = []
+    for diagnostic in code_action_params.context.diagnostics:
+        data = diagnostic.data
+        if not isinstance(data, list):
+            data = [data]
+        for action_suggestion in data:
+            if (
+                action_suggestion
+                and isinstance(action_suggestion, Mapping)
+                and "code_action" in action_suggestion
+            ):
+                action_name: CodeActionName = action_suggestion["code_action"]
+                handler = CODE_ACTION_HANDLERS.get(action_name)
+                if handler is not None:
+                    actions.extend(
+                        handler(
+                            cast("Mapping[str, str]", action_suggestion),
+                            code_action_params,
+                            diagnostic,
+                        )
+                    )
+                else:
+                    _warn(f"No codeAction handler for {action_name} !?")
+    if not actions:
+        return None
+    return actions