1 files changed, 175 insertions, 0 deletions
diff --git a/src/debputy/linting/lint_util.py b/src/debputy/linting/lint_util.py
new file mode 100644
index 0000000..7cdb8b6
--- /dev/null
+++ b/src/debputy/linting/lint_util.py
@@ -0,0 +1,175 @@
+import dataclasses
+from typing import List, Optional, Callable, Counter
+
+from lsprotocol.types import Position, Range, Diagnostic, DiagnosticSeverity
+
+from debputy.commands.debputy_cmd.output import OutputStylingBase
+from debputy.util import _DEFAULT_LOGGER, _warn
+
+LinterImpl = Callable[
+    [str, str, List[str], "LintCapablePositionCodec"], Optional[List[Diagnostic]]
+]
+
+
+@dataclasses.dataclass(slots=True)
+class LintReport:
+    diagnostics_count: Counter[DiagnosticSeverity] = dataclasses.field(
+        default_factory=Counter
+    )
+    diagnostics_without_severity: int = 0
+    diagnostic_errors: int = 0
+    fixed: int = 0
+    fixable: int = 0
+
+
+class LinterPositionCodec:
+
+    def client_num_units(self, chars: str):
+        return len(chars)
+
+    def position_from_client_units(
+        self, lines: List[str], position: Position
+    ) -> Position:
+
+        if len(lines) == 0:
+            return Position(0, 0)
+        if position.line >= len(lines):
+            return Position(len(lines) - 1, self.client_num_units(lines[-1]))
+        return position
+
+    def position_to_client_units(
+        self, _lines: List[str], position: Position
+    ) -> Position:
+        return position
+
+    def range_from_client_units(self, _lines: List[str], range: Range) -> Range:
+        return range
+
+    def range_to_client_units(self, _lines: List[str], range: Range) -> Range:
+        return range
+
+
+LINTER_POSITION_CODEC = LinterPositionCodec()
+
+
+_SEVERITY2TAG = {
+    DiagnosticSeverity.Error: lambda fo: fo.colored(
+        "error",
+        fg="red",
+        bg="black",
+        style="bold",
+    ),
+    DiagnosticSeverity.Warning: lambda fo: fo.colored(
+        "warning",
+        fg="yellow",
+        bg="black",
+        style="bold",
+    ),
+    DiagnosticSeverity.Information: lambda fo: fo.colored(
+        "informational",
+        fg="blue",
+        bg="black",
+        style="bold",
+    ),
+    DiagnosticSeverity.Hint: lambda fo: fo.colored(
+        "pedantic",
+        fg="green",
+        bg="black",
+        style="bold",
+    ),
+}
+
+
+def _lines_to_print(range_: Range) -> int:
+    count = range_.end.line - range_.start.line
+    if range_.end.character > 0:
+        count += 1
+    return count
+
+
+def _highlight_range(
+    fo: OutputStylingBase, line: str, line_no: int, range_: Range
+) -> str:
+    line_wo_nl = line.rstrip("\r\n")
+    start_pos = 0
+    prefix = ""
+    suffix = ""
+    if line_no == range_.start.line:
+        start_pos = range_.start.character
+        prefix = line_wo_nl[0:start_pos]
+    if line_no == range_.end.line:
+        end_pos = range_.end.character
+        suffix = line_wo_nl[end_pos:]
+    else:
+        end_pos = len(line_wo_nl)
+
+    marked_part = fo.colored(line_wo_nl[start_pos:end_pos], fg="red", style="bold")
+
+    return prefix + marked_part + suffix
+
+
+def report_diagnostic(
+    fo: OutputStylingBase,
+    filename: str,
+    diagnostic: Diagnostic,
+    lines: List[str],
+    auto_fixable: bool,
+    auto_fixed: bool,
+    lint_report: LintReport,
+) -> None:
+    logger = _DEFAULT_LOGGER
+    assert logger is not None
+    severity = diagnostic.severity
+    missing_severity = False
+    if severity is None:
+        severity = DiagnosticSeverity.Warning
+        missing_severity = True
+    if not auto_fixed:
+        tag_unresolved = _SEVERITY2TAG.get(severity)
+        if tag_unresolved is None:
+            tag_unresolved = _SEVERITY2TAG[DiagnosticSeverity.Warning]
+            lint_report.diagnostics_without_severity += 1
+        else:
+            lint_report.diagnostics_count[severity] += 1
+        tag = tag_unresolved(fo)
+    else:
+        tag = fo.colored(
+            "auto-fixing",
+            fg="magenta",
+            bg="black",
+            style="bold",
+        )
+    start_line = diagnostic.range.start.line
+    start_position = diagnostic.range.start.character
+    end_line = diagnostic.range.end.line
+    end_position = diagnostic.range.end.character
+    has_fixit = ""
+    line_no_width = len(str(len(lines)))
+    if not auto_fixed and auto_fixable:
+        has_fixit = " [Correctable via --auto-fix]"
+        lint_report.fixable += 1
+    print(
+        f"{tag}: File: {filename}:{start_line+1}:{start_position}:{end_line+1}:{end_position}: {diagnostic.message}{has_fixit}",
+    )
+    if missing_severity:
+        _warn(
+            "  This warning did not have an explicit severity; Used Warning as a fallback!"
+        )
+    if auto_fixed:
+        # If it is fixed, there is no reason to show additional context.
+        lint_report.fixed += 1
+        return
+    lines_to_print = _lines_to_print(diagnostic.range)
+    if diagnostic.range.end.line >= len(lines) or diagnostic.range.start.line < 1:
+        lint_report.diagnostic_errors += 1
+        _warn(
+            "Bug in the underlying linter: The line numbers of the warning does not fit in the file..."
+        )
+        return
+    if lines_to_print == 1:
+        line = _highlight_range(fo, lines[start_line], start_line, diagnostic.range)
+        print(f"    {start_line+1:{line_no_width}}: {line}")
+    else:
+        for line_no in range(start_line, end_line):
+            line = _highlight_range(fo, lines[line_no], line_no, diagnostic.range)
+            print(f"    {line_no+1:{line_no_width}}: {line}")