# Copyright 2017-2020 Palantir Technologies, Inc.
# Copyright 2021- Python Language Server Contributors.

from pyflakes import api as pyflakes_api
from pyflakes import messages

from pylsp import hookimpl, lsp

# Pyflakes messages that should be reported as Errors instead of Warns
PYFLAKES_ERROR_MESSAGES = (
    messages.UndefinedName,
    messages.UndefinedExport,
    messages.UndefinedLocal,
    messages.DuplicateArgument,
    messages.FutureFeatureNotDefined,
    messages.ReturnOutsideFunction,
    messages.YieldOutsideFunction,
    messages.ContinueOutsideLoop,
    messages.BreakOutsideLoop,
    messages.TwoStarredExpressions,
)


@hookimpl
def pylsp_lint(workspace, document):
    with workspace.report_progress("lint: pyflakes"):
        reporter = PyflakesDiagnosticReport(document.lines)
        pyflakes_api.check(
            document.source.encode("utf-8"), document.path, reporter=reporter
        )
        return reporter.diagnostics


class PyflakesDiagnosticReport:
    def __init__(self, lines) -> None:
        self.lines = lines
        self.diagnostics = []

    def unexpectedError(self, _filename, msg) -> None:  # pragma: no cover
        err_range = {
            "start": {"line": 0, "character": 0},
            "end": {"line": 0, "character": 0},
        }
        self.diagnostics.append(
            {
                "source": "pyflakes",
                "range": err_range,
                "message": msg,
                "severity": lsp.DiagnosticSeverity.Error,
            }
        )

    def syntaxError(self, _filename, msg, lineno, offset, text) -> None:
        # We've seen that lineno and offset can sometimes be None
        lineno = lineno or 1
        offset = offset or 0
        # could be None if the error is due to an invalid encoding
        # see e.g. https://github.com/python-lsp/python-lsp-server/issues/429
        text = text or ""

        err_range = {
            "start": {"line": lineno - 1, "character": offset},
            "end": {"line": lineno - 1, "character": offset + len(text)},
        }
        self.diagnostics.append(
            {
                "source": "pyflakes",
                "range": err_range,
                "message": msg,
                "severity": lsp.DiagnosticSeverity.Error,
            }
        )

    def flake(self, message) -> None:
        """Get message like <filename>:<lineno>: <msg>"""
        err_range = {
            "start": {"line": message.lineno - 1, "character": message.col},
            "end": {
                "line": message.lineno - 1,
                "character": len(self.lines[message.lineno - 1]),
            },
        }

        severity = lsp.DiagnosticSeverity.Warning
        for message_type in PYFLAKES_ERROR_MESSAGES:
            if isinstance(message, message_type):
                severity = lsp.DiagnosticSeverity.Error
                break

        self.diagnostics.append(
            {
                "source": "pyflakes",
                "range": err_range,
                "message": message.message % message.message_args,
                "severity": severity,
            }
        )