"""Tests for the .dmp minidump parser (M14) — builds a synthetic MDMP, no external tools."""

import struct
import tempfile
import unittest
from pathlib import Path
from unittest import mock

from rigdoctor.core import minidump


def _synthetic_dump() -> bytes:
    """A minimal but valid MDMP: header + SystemInfo + Exception + 2-module ModuleList.

    Layout (absolute file offsets): header@0, directory@32, SystemInfo@68, Exception@96,
    ModuleList@264, name strings@484. Module0 spans the exception address, so it's faulting.
    """
    buf = bytearray(600)
    struct.pack_into("<4sIIIIIQ", buf, 0, b"MDMP", 0xA793, 3, 32, 0, 1_700_000_000, 0)
    struct.pack_into("<III", buf, 32, 7, 28, 68)     # SystemInfoStream
    struct.pack_into("<III", buf, 44, 6, 168, 96)    # ExceptionStream
    struct.pack_into("<III", buf, 56, 4, 220, 264)   # ModuleListStream

    # SystemInfo: x86-64, 16 CPUs, Windows 10.0.19041 (PlatformId 2 = Win32 NT).
    struct.pack_into("<HHHBBIIIII", buf, 68, 9, 0, 0, 16, 1, 10, 0, 19041, 2, 0)

    # Exception: access violation (write) at 0x140001234.
    struct.pack_into("<I", buf, 96, 4321)            # ThreadId
    struct.pack_into("<I", buf, 96 + 8, 0xC0000005)  # ExceptionCode
    struct.pack_into("<Q", buf, 96 + 24, 0x140001234)  # ExceptionAddress
    struct.pack_into("<I", buf, 96 + 32, 2)          # NumberParameters
    struct.pack_into("<Q", buf, 96 + 40, 1)          # info[0] = write
    struct.pack_into("<Q", buf, 96 + 48, 0x0)        # info[1] = faulting address

    # ModuleList: 2 modules.
    struct.pack_into("<I", buf, 264, 2)
    m0, m1 = 268, 268 + minidump._MODULE_STRIDE
    struct.pack_into("<Q", buf, m0, 0x140000000)     # base
    struct.pack_into("<I", buf, m0 + 8, 0x100000)    # size (spans the exception address)
    struct.pack_into("<I", buf, m0 + 20, 484)        # name RVA
    struct.pack_into("<Q", buf, m1, 0x180000000)
    struct.pack_into("<I", buf, m1 + 8, 0x080000)
    struct.pack_into("<I", buf, m1 + 20, 522)

    name0 = "C:\\Games\\game.exe".encode("utf-16-le")
    struct.pack_into("<I", buf, 484, len(name0))
    buf[488:488 + len(name0)] = name0
    name1 = "nvwgf2umx.dll".encode("utf-16-le")
    struct.pack_into("<I", buf, 522, len(name1))
    buf[526:526 + len(name1)] = name1
    return bytes(buf)


class ParseTests(unittest.TestCase):
    def setUp(self):
        self._tmp = tempfile.NamedTemporaryFile(suffix=".dmp", delete=False)
        self._tmp.write(_synthetic_dump())
        self._tmp.close()
        self.path = self._tmp.name

    def tearDown(self):
        Path(self.path).unlink(missing_ok=True)

    def _parse(self):
        return minidump.parse(self.path, run_stackwalk=False)

    def test_parses_exception_and_faulting_module(self):
        r = self._parse()
        self.assertTrue(r.ok, r.error)
        self.assertEqual(r.exception_code, 0xC0000005)
        self.assertIn("Access violation", r.crash_reason)
        self.assertIn("writing 0x0", r.crash_reason)
        self.assertEqual(r.faulting_module, "game.exe")  # basename, address inside module0
        self.assertEqual(r.crashing_thread, 4321)

    def test_parses_system_info_and_modules(self):
        r = self._parse()
        self.assertEqual(r.os_name, "Windows 10.0.19041")
        self.assertEqual(r.cpu_arch, "x86-64")
        self.assertEqual(r.cpu_count, 16)
        self.assertEqual([m.name for m in r.modules], ["game.exe", "nvwgf2umx.dll"])

    def test_to_text_and_ai_text(self):
        r = self._parse()
        text = minidump.to_text(r)
        self.assertIn("game.exe", text)
        self.assertIn("nvwgf2umx.dll", text)
        self.assertIn("Access violation", text)
        ai_text = minidump.to_ai_text(r)
        self.assertIn("Proton", ai_text)       # Linux/Proton framing for the model
        self.assertIn("Crash reason", ai_text)

    def test_to_findings(self):
        findings = minidump.to_findings(self._parse())
        self.assertEqual(findings[0].severity, minidump.CRITICAL)
        self.assertIn("game.exe", findings[0].title)

    def test_run_stackwalk_false_skips_external_tool(self):
        self.assertEqual(self._parse().stackwalk, "")


class RobustnessTests(unittest.TestCase):
    def test_non_minidump_file(self):
        with tempfile.NamedTemporaryFile(suffix=".dmp", delete=False) as fh:
            fh.write(b"not a dump at all")
            path = fh.name
        try:
            r = minidump.parse(path, run_stackwalk=False)
        finally:
            Path(path).unlink(missing_ok=True)
        self.assertFalse(r.ok)
        self.assertIn("signature", r.error)

    def test_missing_file(self):
        r = minidump.parse("/nonexistent/does-not-exist.dmp", run_stackwalk=False)
        self.assertFalse(r.ok)
        self.assertIn("can't read", r.error)

    def test_stackwalk_absent_returns_empty(self):
        with mock.patch.object(minidump.shutil, "which", return_value=None):
            self.assertEqual(minidump.stackwalk("/whatever.dmp"), "")


class CliDumpTests(unittest.TestCase):
    """`rigdoctor ai dump <file>` parses then explains via the configured provider."""

    def _args(self, **over):
        import argparse
        base = {"ai_cmd": "dump", "file": ""}
        base.update(over)
        return argparse.Namespace(**base)

    def test_dump_parses_and_explains(self):
        from rigdoctor.core import ai

        with tempfile.NamedTemporaryFile(suffix=".dmp", delete=False) as fh:
            fh.write(_synthetic_dump())
            path = fh.name
        try:
            with mock.patch.object(ai, "is_configured", return_value=True), \
                 mock.patch.object(ai, "provider_label", return_value="Claude (test)"), \
                 mock.patch.object(minidump, "stackwalk", return_value=""), \
                 mock.patch.object(ai, "explain", return_value=(True, "Likely DXVK.")) as explain:
                from rigdoctor import cli
                rc = cli.cmd_ai(self._args(file=path))
        finally:
            Path(path).unlink(missing_ok=True)
        self.assertEqual(rc, 0)
        sent = explain.call_args[0][0]
        self.assertIn("Proton", sent)         # the Linux/Proton framing reached the model
        self.assertIn("game.exe", sent)

    def test_dump_bad_file_returns_error(self):
        from rigdoctor.core import ai

        with mock.patch.object(ai, "is_configured", return_value=True):
            from rigdoctor import cli
            rc = cli.cmd_ai(self._args(file="/nope/missing.dmp"))
        self.assertEqual(rc, 1)


if __name__ == "__main__":
    unittest.main()