import logging
import os
import pathlib
import stat
import subprocess
import threading
from collections.abc import Hashable
from typing import Any, cast

from overrides import override

from solidlsp.ls import RawDocumentSymbol, SolidLanguageServer
from solidlsp.ls_config import Language, LanguageServerConfig
from solidlsp.ls_utils import FileUtils, PlatformId, PlatformUtils
from solidlsp.lsp_protocol_handler.lsp_types import InitializeParams
from solidlsp.lsp_protocol_handler.server import ProcessLaunchInfo
from solidlsp.settings import SolidLSPSettings

from ..common import RuntimeDependency

log = logging.getLogger(__name__)

EXPERT_VERSION = "v0.1.0-rc.6"
EXPERT_ALLOWED_HOSTS = (
    "github.com",
    "release-assets.githubusercontent.com",
    "objects.githubusercontent.com",
)


class ElixirTools(SolidLanguageServer):
    """
    Provides Elixir specific instantiation of the LanguageServer class using Expert, the official Elixir language server.

    You can pass the following entries in ``ls_specific_settings["elixir"]``:
        - expert_version: Override the pinned Expert version downloaded by Serena
          (default: the bundled Serena version).
    """

    @override
    def _get_wait_time_for_cross_file_referencing(self) -> float:
        return 10.0  # Elixir projects need time to compile and index before cross-file references work

    @override
    def is_ignored_dirname(self, dirname: str) -> bool:
        # For Elixir projects, we should ignore:
        # - _build: compiled artifacts
        # - deps: dependencies
        # - node_modules: if the project has JavaScript components
        # - .elixir_ls: ElixirLS artifacts (in case both are present)
        # - cover: coverage reports
        # - .expert: Expert artifacts
        return super().is_ignored_dirname(dirname) or dirname in ["_build", "deps", "node_modules", ".elixir_ls", ".expert", "cover"]

    @override
    def is_ignored_path(self, relative_path: str, ignore_unsupported_files: bool = True) -> bool:
        """Check if a path should be ignored for symbol indexing."""
        if relative_path.endswith("mix.exs"):
            # These are project configuration files, not source code with symbols to index
            return True

        return super().is_ignored_path(relative_path, ignore_unsupported_files)

    @classmethod
    def _get_elixir_version(cls) -> str | None:
        """Get the installed Elixir version or None if not found."""
        try:
            result = subprocess.run(["elixir", "--version"], capture_output=True, text=True, check=False)
            if result.returncode == 0:
                return result.stdout.strip()
        except FileNotFoundError:
            return None
        return None

    @classmethod
    def _setup_runtime_dependencies(cls, config: LanguageServerConfig, solidlsp_settings: SolidLSPSettings) -> str:
        """
        Setup runtime dependencies for Expert.
        Downloads the Expert binary for the current platform and returns the path to the executable.
        """
        elixir_settings = solidlsp_settings.get_ls_specific_settings(Language.ELIXIR)
        expert_version = elixir_settings.get("expert_version", EXPERT_VERSION)
        # Check if Elixir is available first
        elixir_version = cls._get_elixir_version()
        if not elixir_version:
            raise RuntimeError(
                "Elixir is not installed. Please install Elixir from https://elixir-lang.org/install.html and make sure it is added to your PATH."
            )

        log.info(f"Found Elixir: {elixir_version}")

        # First, check if expert is already in PATH (user may have installed it manually)
        import shutil

        expert_in_path = shutil.which("expert")
        if expert_in_path:
            log.info(f"Found Expert in PATH: {expert_in_path}")
            return expert_in_path

        platform_id = PlatformUtils.get_platform_id()

        valid_platforms = [
            PlatformId.LINUX_x64,
            PlatformId.LINUX_arm64,
            PlatformId.OSX_x64,
            PlatformId.OSX_arm64,
            PlatformId.WIN_x64,
        ]
        assert platform_id in valid_platforms, f"Platform {platform_id} is not supported for Expert at the moment"

        expert_dir = os.path.join(cls.ls_resources_dir(solidlsp_settings), "expert")

        # Define runtime dependencies inline
        runtime_deps = {
            PlatformId.LINUX_x64: RuntimeDependency(
                id="expert_linux_amd64",
                platform_id="linux-x64",
                url=f"https://github.com/elixir-lang/expert/releases/download/{expert_version}/expert_linux_amd64",
                archive_type="binary",
                binary_name="expert_linux_amd64",
                extract_path="expert",
                sha256="643a492ff972246668b0ca356a84c3d0a0f5feeae0ab5dc1b9a126876ed460e4" if expert_version == EXPERT_VERSION else None,
                allowed_hosts=EXPERT_ALLOWED_HOSTS,
            ),
            PlatformId.LINUX_arm64: RuntimeDependency(
                id="expert_linux_arm64",
                platform_id="linux-arm64",
                url=f"https://github.com/elixir-lang/expert/releases/download/{expert_version}/expert_linux_arm64",
                archive_type="binary",
                binary_name="expert_linux_arm64",
                extract_path="expert",
                sha256="d8b830bdaa8991d7ebf255dacbb3674f3ea335c87d0bfba4b7f907ded4a8f014" if expert_version == EXPERT_VERSION else None,
                allowed_hosts=EXPERT_ALLOWED_HOSTS,
            ),
            PlatformId.OSX_x64: RuntimeDependency(
                id="expert_darwin_amd64",
                platform_id="osx-x64",
                url=f"https://github.com/elixir-lang/expert/releases/download/{expert_version}/expert_darwin_amd64",
                archive_type="binary",
                binary_name="expert_darwin_amd64",
                extract_path="expert",
                sha256="964f316f1633090b33aab392b6b85fb778c5fb3c0db862671424458da34b1d4d" if expert_version == EXPERT_VERSION else None,
                allowed_hosts=EXPERT_ALLOWED_HOSTS,
            ),
            PlatformId.OSX_arm64: RuntimeDependency(
                id="expert_darwin_arm64",
                platform_id="osx-arm64",
                url=f"https://github.com/elixir-lang/expert/releases/download/{expert_version}/expert_darwin_arm64",
                archive_type="binary",
                binary_name="expert_darwin_arm64",
                extract_path="expert",
                sha256="5fb5be151baedd635d99835cf3f9986afc9af6ae7b07bd001a1962f4298e45da" if expert_version == EXPERT_VERSION else None,
                allowed_hosts=EXPERT_ALLOWED_HOSTS,
            ),
            PlatformId.WIN_x64: RuntimeDependency(
                id="expert_windows_amd64",
                platform_id="win-x64",
                url=f"https://github.com/elixir-lang/expert/releases/download/{expert_version}/expert_windows_amd64.exe",
                archive_type="binary",
                binary_name="expert_windows_amd64.exe",
                extract_path="expert.exe",
                sha256="babee77d2653679021600b99c68d984d4463290cb221e0fc0d1093b3afdeb3b0" if expert_version == EXPERT_VERSION else None,
                allowed_hosts=EXPERT_ALLOWED_HOSTS,
            ),
        }

        dependency = runtime_deps[platform_id]
        # On Windows, use .exe extension
        executable_name = "expert.exe" if platform_id.value.startswith("win") else "expert"
        executable_path = os.path.join(expert_dir, executable_name)
        assert dependency.binary_name is not None
        binary_path = os.path.join(expert_dir, dependency.binary_name)

        if not os.path.exists(executable_path):
            log.info(f"Downloading Expert binary from {dependency.url}")
            assert dependency.url is not None
            FileUtils.download_file_verified(
                dependency.url,
                binary_path,
                expected_sha256=dependency.sha256,
                allowed_hosts=dependency.allowed_hosts,
            )

            # Make the binary executable on Unix-like systems
            if not platform_id.value.startswith("win"):
                os.chmod(binary_path, stat.S_IRWXU | stat.S_IRGRP | stat.S_IXGRP | stat.S_IROTH | stat.S_IXOTH)

            # Create a symlink with the expected name on Unix-like systems
            if binary_path != executable_path and not platform_id.value.startswith("win"):
                if os.path.exists(executable_path):
                    os.remove(executable_path)
                os.symlink(os.path.basename(binary_path), executable_path)

            # normalizing the executable name on Windows
            if binary_path != executable_path and platform_id.value.startswith("win"):
                shutil.copy2(binary_path, executable_path)

        assert os.path.exists(executable_path), f"Expert executable not found at {executable_path}"

        log.info(f"Expert binary ready at: {executable_path}")
        return executable_path

    def __init__(self, config: LanguageServerConfig, repository_root_path: str, solidlsp_settings: SolidLSPSettings):
        expert_executable_path = self._setup_runtime_dependencies(config, solidlsp_settings)

        super().__init__(
            config,
            repository_root_path,
            ProcessLaunchInfo(cmd=f"{expert_executable_path} --stdio", cwd=repository_root_path),
            "elixir",
            solidlsp_settings,
        )
        self.server_ready = threading.Event()
        self.request_id = 0

        # Set generous timeout for Expert which can be slow to initialize and respond
        self.set_request_timeout(180.0)

    @override
    def _document_symbols_cache_fingerprint(self) -> Hashable:
        normalize_symbol_name_version = 1
        return normalize_symbol_name_version

    @override
    def _normalize_symbol_name(self, symbol: RawDocumentSymbol, relative_file_path: str) -> str:
        return symbol["name"].removeprefix("defp ").removeprefix("def ").split("(", 1)[0].strip()

    def _find_mix_exs(self) -> str | None:
        """
        Find mix.exs in the repository.

        Checks {repository_root_path}/mix.exs first (standard layout), then scans
        immediate subdirectories for mix.exs (monorepo layout, e.g. server/mix.exs).
        Returns the absolute path to the first match found, or None if not found.

        Note: subdirectory iteration order depends on the filesystem (os.listdir).
        In practice this is fine — monorepos typically have one Elixir app.
        """
        # Check root first
        root_mix_exs = os.path.join(self.repository_root_path, "mix.exs")
        if os.path.exists(root_mix_exs):
            return root_mix_exs

        # Search immediate subdirectories
        try:
            for entry in os.listdir(self.repository_root_path):
                subdir_path = os.path.join(self.repository_root_path, entry)
                if os.path.isdir(subdir_path):
                    subdir_mix_exs = os.path.join(subdir_path, "mix.exs")
                    if os.path.exists(subdir_mix_exs):
                        log.info(f"Found mix.exs in subdirectory: {entry}/mix.exs")
                        return subdir_mix_exs
        except OSError as e:
            log.warning(f"Error scanning for mix.exs in subdirectories: {e}")

        return None

    @staticmethod
    def _get_initialize_params(repository_absolute_path: str) -> InitializeParams:
        """
        Returns the initialize params for the Expert Language Server.
        """
        # Ensure the path is absolute
        abs_path = os.path.abspath(repository_absolute_path)
        root_uri = pathlib.Path(abs_path).as_uri()
        initialize_params = {
            "processId": os.getpid(),
            "locale": "en",
            "rootPath": abs_path,
            "rootUri": root_uri,
            "initializationOptions": {
                "mix_env": "dev",
                "mix_target": "host",
                "experimental": {"completions": {"enable": False}},
                "extensions": {"credo": {"enable": True, "cli_options": []}},
            },
            "capabilities": {
                "textDocument": {
                    "synchronization": {"didSave": True, "dynamicRegistration": True},
                    "completion": {
                        "dynamicRegistration": True,
                        "completionItem": {"snippetSupport": True, "documentationFormat": ["markdown", "plaintext"]},
                    },
                    "definition": {"dynamicRegistration": True},
                    "references": {"dynamicRegistration": True},
                    "documentSymbol": {
                        "dynamicRegistration": True,
                        "hierarchicalDocumentSymbolSupport": True,
                        "symbolKind": {"valueSet": list(range(1, 27))},
                    },
                    "hover": {"dynamicRegistration": True, "contentFormat": ["markdown", "plaintext"]},
                    "formatting": {"dynamicRegistration": True},
                    "codeAction": {
                        "dynamicRegistration": True,
                        "codeActionLiteralSupport": {
                            "codeActionKind": {
                                "valueSet": [
                                    "quickfix",
                                    "refactor",
                                    "refactor.extract",
                                    "refactor.inline",
                                    "refactor.rewrite",
                                    "source",
                                    "source.organizeImports",
                                ]
                            }
                        },
                    },
                },
                "workspace": {
                    "workspaceFolders": True,
                    "didChangeConfiguration": {"dynamicRegistration": True},
                    "executeCommand": {"dynamicRegistration": True},
                },
                "window": {
                    "showMessage": {"messageActionItem": {"additionalPropertiesSupport": True}},
                    "showDocument": {"support": True},
                    "workDoneProgress": True,
                },
            },
            "workspaceFolders": [{"uri": root_uri, "name": os.path.basename(repository_absolute_path)}],
        }

        return cast(InitializeParams, initialize_params)

    def _start_server(self) -> None:
        """Start Expert server process"""

        def register_capability_handler(params: Any) -> None:
            log.debug(f"LSP: client/registerCapability: {params}")
            return

        def window_log_message(msg: Any) -> None:
            """Handle window/logMessage notifications from Expert"""
            message_type = msg.get("type", 4)  # 1=Error, 2=Warning, 3=Info, 4=Log
            message_text = msg.get("message", "")

            # Log at appropriate level based on message type
            if message_type == 1:
                log.error(f"Expert: {message_text}")
            elif message_type == 2:
                log.warning(f"Expert: {message_text}")
            else:
                log.debug(f"Expert: {message_text}")

        def check_server_ready(params: Any) -> None:
            """
            Handle $/progress notifications from Expert.
            Expert sends progress updates during compilation and indexing.
            The server is considered ready when project build completes.
            """
            value = params.get("value", {})
            kind = value.get("kind", "")
            title = value.get("title", "")

            if kind == "begin":
                # Track when building the project starts (not "Building engine")
                if title.startswith("Building ") and not title.startswith("Building engine"):
                    self._building_project = True
            elif kind == "end":
                # Project build completion is the main readiness signal
                if getattr(self, "_building_project", False):
                    log.debug("Expert project build completed - server is ready")
                    self._building_project = False
                    self.server_ready.set()

        def work_done_progress_create(params: Any) -> None:
            """Handle window/workDoneProgress/create requests from Expert."""
            return

        def publish_diagnostics(params: Any) -> None:
            """Handle textDocument/publishDiagnostics notifications."""
            return

        self.server.on_request("client/registerCapability", register_capability_handler)
        self.server.on_notification("window/logMessage", window_log_message)
        self.server.on_notification("$/progress", check_server_ready)
        self.server.on_request("window/workDoneProgress/create", work_done_progress_create)
        self.server.on_notification("textDocument/publishDiagnostics", publish_diagnostics)

        log.debug("Starting Expert server process")
        self.server.start()
        initialize_params = self._get_initialize_params(self.repository_root_path)

        log.debug("Sending initialize request to Expert")
        init_response = self.server.send.initialize(initialize_params)

        # Verify basic server capabilities
        assert "textDocumentSync" in init_response["capabilities"], f"Missing textDocumentSync in {init_response['capabilities']}"

        self.server.notify.initialized({})

        # Expert's build pipeline is triggered by a textDocument/didOpen notification.
        # Without it Expert sits idle and never emits the $/progress signals we wait for,
        # causing a deadlock. Opening mix.exs is the minimal trigger; we close it again
        # once the server is ready so it does not linger in the open-file set.
        mix_exs_path = self._find_mix_exs()
        mix_exs_uri: str | None = None

        if mix_exs_path is not None:
            mix_exs_uri = pathlib.Path(mix_exs_path).as_uri()
            with open(mix_exs_path, encoding="utf-8") as f:
                mix_exs_content = f.read()
            self.server.notify.did_open_text_document(
                {
                    "textDocument": {
                        "uri": mix_exs_uri,
                        "languageId": "elixir",
                        "version": 1,
                        "text": mix_exs_content,
                    }
                }
            )
            log.debug("Opened mix.exs to trigger Expert's build pipeline")

        # Expert needs time to compile the project and build indexes on first run.
        # This can take 2-3+ minutes for mid-sized codebases.
        # After the first run, subsequent startups are much faster.
        ready_timeout = 300.0  # 5 minutes
        log.debug(f"Waiting up to {ready_timeout}s for Expert to compile and index...")
        if self.server_ready.wait(timeout=ready_timeout):
            log.debug("Expert is ready for requests")
        else:
            log.warning(f"Expert did not signal readiness within {ready_timeout}s. Proceeding with requests anyway.")
            self.server_ready.set()  # Mark as ready anyway to allow requests

        if mix_exs_uri is not None:
            self.server.notify.did_close_text_document({"textDocument": {"uri": mix_exs_uri}})
            log.debug("Closed mix.exs after Expert is ready")
