//! Advertises the capabilities of the LSP Server.
use ide::{CompletionFieldsToResolve, InlayFieldsToResolve};
use ide_db::{FxHashSet, line_index::WideEncoding};
use lsp_types::{
    CallHierarchyServerCapability, CodeActionKind, CodeActionOptions, CodeActionProviderCapability,
    CodeLensOptions, CompletionOptions, CompletionOptionsCompletionItem, DeclarationCapability,
    DocumentOnTypeFormattingOptions, FileOperationFilter, FileOperationPattern,
    FileOperationPatternKind, FileOperationRegistrationOptions, FoldingRangeProviderCapability,
    HoverProviderCapability, ImplementationProviderCapability, InlayHintOptions,
    InlayHintServerCapabilities, OneOf, PositionEncodingKind, RenameOptions, SaveOptions,
    SelectionRangeProviderCapability, SemanticTokensFullOptions, SemanticTokensLegend,
    SemanticTokensOptions, ServerCapabilities, SignatureHelpOptions, TextDocumentSyncCapability,
    TextDocumentSyncKind, TextDocumentSyncOptions, TypeDefinitionProviderCapability,
    WorkDoneProgressOptions, WorkspaceFileOperationsServerCapabilities,
    WorkspaceFoldersServerCapabilities, WorkspaceServerCapabilities,
};
use serde_json::json;

use crate::{
    config::{Config, RustfmtConfig},
    line_index::PositionEncoding,
    lsp::{ext, semantic_tokens},
};

pub fn server_capabilities(config: &Config) -> ServerCapabilities {
    ServerCapabilities {
        position_encoding: match config.caps().negotiated_encoding() {
            PositionEncoding::Utf8 => Some(PositionEncodingKind::UTF8),
            PositionEncoding::Wide(wide) => match wide {
                WideEncoding::Utf16 => Some(PositionEncodingKind::UTF16),
                WideEncoding::Utf32 => Some(PositionEncodingKind::UTF32),
                _ => None,
            },
        },
        text_document_sync: Some(TextDocumentSyncCapability::Options(TextDocumentSyncOptions {
            open_close: Some(true),
            change: Some(TextDocumentSyncKind::INCREMENTAL),
            will_save: None,
            will_save_wait_until: None,
            save: if config.caps().did_save_text_document_dynamic_registration() {
                None
            } else {
                Some(SaveOptions::default().into())
            },
        })),
        hover_provider: Some(HoverProviderCapability::Simple(true)),
        completion_provider: Some(CompletionOptions {
            resolve_provider: if config.client_is_neovim() {
                config.has_completion_item_resolve_additionalTextEdits().then_some(true)
            } else {
                Some(config.caps().completions_resolve_provider())
            },
            trigger_characters: Some(vec![
                ":".to_owned(),
                ".".to_owned(),
                "'".to_owned(),
                "(".to_owned(),
            ]),
            all_commit_characters: None,
            completion_item: config.caps().completion_item(),
            work_done_progress_options: WorkDoneProgressOptions { work_done_progress: None },
        }),
        signature_help_provider: Some(SignatureHelpOptions {
            trigger_characters: Some(vec!["(".to_owned(), ",".to_owned(), "<".to_owned()]),
            retrigger_characters: None,
            work_done_progress_options: WorkDoneProgressOptions { work_done_progress: None },
        }),
        declaration_provider: Some(DeclarationCapability::Simple(true)),
        definition_provider: Some(OneOf::Left(true)),
        type_definition_provider: Some(TypeDefinitionProviderCapability::Simple(true)),
        implementation_provider: Some(ImplementationProviderCapability::Simple(true)),
        references_provider: Some(OneOf::Left(true)),
        document_highlight_provider: Some(OneOf::Left(true)),
        document_symbol_provider: Some(OneOf::Left(true)),
        workspace_symbol_provider: Some(OneOf::Left(true)),
        code_action_provider: Some(config.caps().code_action_capabilities()),
        code_lens_provider: Some(CodeLensOptions { resolve_provider: Some(true) }),
        document_formatting_provider: Some(OneOf::Left(true)),
        document_range_formatting_provider: match config.rustfmt(None) {
            RustfmtConfig::Rustfmt { enable_range_formatting: true, .. } => Some(OneOf::Left(true)),
            _ => Some(OneOf::Left(false)),
        },
        document_on_type_formatting_provider: Some({
            let mut chars = ide::Analysis::SUPPORTED_TRIGGER_CHARS.iter();
            DocumentOnTypeFormattingOptions {
                first_trigger_character: chars.next().unwrap().to_string(),
                more_trigger_character: Some(chars.map(|c| c.to_string()).collect()),
            }
        }),
        selection_range_provider: Some(SelectionRangeProviderCapability::Simple(true)),
        folding_range_provider: Some(FoldingRangeProviderCapability::Simple(true)),
        rename_provider: Some(OneOf::Right(RenameOptions {
            prepare_provider: Some(true),
            work_done_progress_options: WorkDoneProgressOptions { work_done_progress: None },
        })),
        linked_editing_range_provider: None,
        document_link_provider: None,
        color_provider: None,
        execute_command_provider: None,
        workspace: Some(WorkspaceServerCapabilities {
            workspace_folders: Some(WorkspaceFoldersServerCapabilities {
                supported: Some(true),
                change_notifications: Some(OneOf::Left(true)),
            }),
            file_operations: Some(WorkspaceFileOperationsServerCapabilities {
                did_create: None,
                will_create: None,
                did_rename: None,
                will_rename: Some(FileOperationRegistrationOptions {
                    filters: vec![
                        FileOperationFilter {
                            scheme: Some(String::from("file")),
                            pattern: FileOperationPattern {
                                glob: String::from("**/*.rs"),
                                matches: Some(FileOperationPatternKind::File),
                                options: None,
                            },
                        },
                        FileOperationFilter {
                            scheme: Some(String::from("file")),
                            pattern: FileOperationPattern {
                                glob: String::from("**"),
                                matches: Some(FileOperationPatternKind::Folder),
                                options: None,
                            },
                        },
                    ],
                }),
                did_delete: None,
                will_delete: None,
            }),
        }),
        call_hierarchy_provider: Some(CallHierarchyServerCapability::Simple(true)),
        semantic_tokens_provider: Some(
            SemanticTokensOptions {
                legend: SemanticTokensLegend {
                    token_types: semantic_tokens::SUPPORTED_TYPES.to_vec(),
                    token_modifiers: semantic_tokens::SUPPORTED_MODIFIERS.to_vec(),
                },

                full: Some(SemanticTokensFullOptions::Delta { delta: Some(true) }),
                range: Some(true),
                work_done_progress_options: Default::default(),
            }
            .into(),
        ),
        moniker_provider: None,
        inlay_hint_provider: Some(OneOf::Right(InlayHintServerCapabilities::Options(
            InlayHintOptions {
                work_done_progress_options: Default::default(),
                resolve_provider: Some(config.caps().inlay_hints_resolve_provider()),
            },
        ))),
        inline_value_provider: None,
        experimental: Some(json!({
            "externalDocs": true,
            "hoverRange": true,
            "joinLines": true,
            "matchingBrace": true,
            "moveItem": true,
            "onEnter": true,
            "openCargoToml": true,
            "parentModule": true,
            "childModules": true,
            "runnables": {
                "kinds": [ "cargo" ],
            },
            "ssr": true,
            "workspaceSymbolScopeKindFiltering": true,
        })),
        diagnostic_provider: Some(lsp_types::DiagnosticServerCapabilities::Options(
            lsp_types::DiagnosticOptions {
                identifier: Some("rust-analyzer".to_owned()),
                inter_file_dependencies: true,
                // FIXME
                workspace_diagnostics: false,
                work_done_progress_options: WorkDoneProgressOptions { work_done_progress: None },
            },
        )),
        inline_completion_provider: None,
    }
}

#[derive(Debug, PartialEq, Clone, Default)]
pub struct ClientCapabilities(lsp_types::ClientCapabilities);

impl ClientCapabilities {
    pub fn new(caps: lsp_types::ClientCapabilities) -> Self {
        Self(caps)
    }

    fn completions_resolve_provider(&self) -> bool {
        let client_capabilities = self.completion_resolve_support_properties();
        let fields_to_resolve =
            CompletionFieldsToResolve::from_client_capabilities(&client_capabilities);
        fields_to_resolve != CompletionFieldsToResolve::empty()
    }

    fn inlay_hints_resolve_provider(&self) -> bool {
        let client_capabilities = self.inlay_hint_resolve_support_properties();
        let fields_to_resolve =
            InlayFieldsToResolve::from_client_capabilities(&client_capabilities);
        fields_to_resolve != InlayFieldsToResolve::empty()
    }

    fn experimental_bool(&self, index: &'static str) -> bool {
        || -> _ { self.0.experimental.as_ref()?.get(index)?.as_bool() }().unwrap_or_default()
    }

    fn experimental<T: serde::de::DeserializeOwned>(&self, index: &'static str) -> Option<T> {
        serde_json::from_value(self.0.experimental.as_ref()?.get(index)?.clone()).ok()
    }

    #[allow(non_snake_case)]
    pub fn has_completion_item_resolve_additionalTextEdits(&self) -> bool {
        (|| {
            Some(
                self.0
                    .text_document
                    .as_ref()?
                    .completion
                    .as_ref()?
                    .completion_item
                    .as_ref()?
                    .resolve_support
                    .as_ref()?
                    .properties
                    .iter()
                    .any(|cap_string| cap_string.as_str() == "additionalTextEdits"),
            )
        })() == Some(true)
    }

    pub fn completion_label_details_support(&self) -> bool {
        (|| -> _ {
            self.0
                .text_document
                .as_ref()?
                .completion
                .as_ref()?
                .completion_item
                .as_ref()?
                .label_details_support
        })() == Some(true)
    }

    fn completion_item(&self) -> Option<CompletionOptionsCompletionItem> {
        Some(CompletionOptionsCompletionItem {
            label_details_support: Some(self.completion_label_details_support()),
        })
    }

    fn code_action_capabilities(&self) -> CodeActionProviderCapability {
        self.0
            .text_document
            .as_ref()
            .and_then(|it| it.code_action.as_ref())
            .and_then(|it| it.code_action_literal_support.as_ref())
            .map_or(CodeActionProviderCapability::Simple(true), |_| {
                CodeActionProviderCapability::Options(CodeActionOptions {
                    // Advertise support for all built-in CodeActionKinds.
                    // Ideally we would base this off of the client capabilities
                    // but the client is supposed to fall back gracefully for unknown values.
                    code_action_kinds: Some(vec![
                        CodeActionKind::EMPTY,
                        CodeActionKind::QUICKFIX,
                        CodeActionKind::REFACTOR,
                        CodeActionKind::REFACTOR_EXTRACT,
                        CodeActionKind::REFACTOR_INLINE,
                        CodeActionKind::REFACTOR_REWRITE,
                    ]),
                    resolve_provider: Some(true),
                    work_done_progress_options: Default::default(),
                })
            })
    }

    pub fn negotiated_encoding(&self) -> PositionEncoding {
        let client_encodings = match &self.0.general {
            Some(general) => general.position_encodings.as_deref().unwrap_or_default(),
            None => &[],
        };

        for enc in client_encodings {
            if enc == &PositionEncodingKind::UTF8 {
                return PositionEncoding::Utf8;
            } else if enc == &PositionEncodingKind::UTF32 {
                return PositionEncoding::Wide(WideEncoding::Utf32);
            }
            // NB: intentionally prefer just about anything else to utf-16.
        }

        PositionEncoding::Wide(WideEncoding::Utf16)
    }

    pub fn workspace_edit_resource_operations(
        &self,
    ) -> Option<&[lsp_types::ResourceOperationKind]> {
        self.0.workspace.as_ref()?.workspace_edit.as_ref()?.resource_operations.as_deref()
    }

    pub fn semantics_tokens_augments_syntax_tokens(&self) -> bool {
        (|| -> _ {
            self.0.text_document.as_ref()?.semantic_tokens.as_ref()?.augments_syntax_tokens
        })()
        .unwrap_or(false)
    }

    pub fn did_save_text_document_dynamic_registration(&self) -> bool {
        let caps = (|| -> _ { self.0.text_document.as_ref()?.synchronization.clone() })()
            .unwrap_or_default();
        caps.did_save == Some(true) && caps.dynamic_registration == Some(true)
    }

    pub fn did_change_watched_files_dynamic_registration(&self) -> bool {
        (|| -> _ {
            self.0.workspace.as_ref()?.did_change_watched_files.as_ref()?.dynamic_registration
        })()
        .unwrap_or_default()
    }

    pub fn did_change_watched_files_relative_pattern_support(&self) -> bool {
        (|| -> _ {
            self.0.workspace.as_ref()?.did_change_watched_files.as_ref()?.relative_pattern_support
        })()
        .unwrap_or_default()
    }

    pub fn location_link(&self) -> bool {
        (|| -> _ { self.0.text_document.as_ref()?.definition?.link_support })().unwrap_or_default()
    }

    pub fn line_folding_only(&self) -> bool {
        (|| -> _ { self.0.text_document.as_ref()?.folding_range.as_ref()?.line_folding_only })()
            .unwrap_or_default()
    }

    pub fn hierarchical_symbols(&self) -> bool {
        (|| -> _ {
            self.0
                .text_document
                .as_ref()?
                .document_symbol
                .as_ref()?
                .hierarchical_document_symbol_support
        })()
        .unwrap_or_default()
    }

    pub fn code_action_literals(&self) -> bool {
        (|| -> _ {
            self.0
                .text_document
                .as_ref()?
                .code_action
                .as_ref()?
                .code_action_literal_support
                .as_ref()
        })()
        .is_some()
    }

    pub fn work_done_progress(&self) -> bool {
        (|| -> _ { self.0.window.as_ref()?.work_done_progress })().unwrap_or_default()
    }

    pub fn will_rename(&self) -> bool {
        (|| -> _ { self.0.workspace.as_ref()?.file_operations.as_ref()?.will_rename })()
            .unwrap_or_default()
    }

    pub fn change_annotation_support(&self) -> bool {
        (|| -> _ {
            self.0.workspace.as_ref()?.workspace_edit.as_ref()?.change_annotation_support.as_ref()
        })()
        .is_some()
    }

    pub fn code_action_resolve(&self) -> bool {
        (|| -> _ {
            Some(
                self.0
                    .text_document
                    .as_ref()?
                    .code_action
                    .as_ref()?
                    .resolve_support
                    .as_ref()?
                    .properties
                    .as_slice(),
            )
        })()
        .unwrap_or_default()
        .iter()
        .any(|it| it == "edit")
    }

    pub fn signature_help_label_offsets(&self) -> bool {
        (|| -> _ {
            self.0
                .text_document
                .as_ref()?
                .signature_help
                .as_ref()?
                .signature_information
                .as_ref()?
                .parameter_information
                .as_ref()?
                .label_offset_support
        })()
        .unwrap_or_default()
    }

    pub fn text_document_diagnostic(&self) -> bool {
        (|| -> _ { self.0.text_document.as_ref()?.diagnostic.as_ref() })().is_some()
    }

    pub fn text_document_diagnostic_related_document_support(&self) -> bool {
        (|| -> _ { self.0.text_document.as_ref()?.diagnostic.as_ref()?.related_document_support })()
            == Some(true)
    }

    pub fn code_action_group(&self) -> bool {
        self.experimental_bool("codeActionGroup")
    }

    pub fn commands(&self) -> Option<ext::ClientCommandOptions> {
        self.experimental("commands")
    }

    pub fn local_docs(&self) -> bool {
        self.experimental_bool("localDocs")
    }

    pub fn open_server_logs(&self) -> bool {
        self.experimental_bool("openServerLogs")
    }

    pub fn server_status_notification(&self) -> bool {
        self.experimental_bool("serverStatusNotification")
    }

    pub fn snippet_text_edit(&self) -> bool {
        self.experimental_bool("snippetTextEdit")
    }

    pub fn hover_actions(&self) -> bool {
        self.experimental_bool("hoverActions")
    }

    /// Whether the client supports colored output for full diagnostics from `checkOnSave`.
    pub fn color_diagnostic_output(&self) -> bool {
        self.experimental_bool("colorDiagnosticOutput")
    }

    pub fn test_explorer(&self) -> bool {
        self.experimental_bool("testExplorer")
    }

    pub fn completion_snippet(&self) -> bool {
        (|| -> _ {
            self.0
                .text_document
                .as_ref()?
                .completion
                .as_ref()?
                .completion_item
                .as_ref()?
                .snippet_support
        })()
        .unwrap_or_default()
    }

    pub fn semantic_tokens_refresh(&self) -> bool {
        (|| -> _ { self.0.workspace.as_ref()?.semantic_tokens.as_ref()?.refresh_support })()
            .unwrap_or_default()
    }

    pub fn code_lens_refresh(&self) -> bool {
        (|| -> _ { self.0.workspace.as_ref()?.code_lens.as_ref()?.refresh_support })()
            .unwrap_or_default()
    }

    pub fn inlay_hints_refresh(&self) -> bool {
        (|| -> _ { self.0.workspace.as_ref()?.inlay_hint.as_ref()?.refresh_support })()
            .unwrap_or_default()
    }

    pub fn diagnostics_refresh(&self) -> bool {
        (|| -> _ { self.0.workspace.as_ref()?.diagnostic.as_ref()?.refresh_support })()
            .unwrap_or_default()
    }

    pub fn inlay_hint_resolve_support_properties(&self) -> FxHashSet<&str> {
        self.0
            .text_document
            .as_ref()
            .and_then(|text| text.inlay_hint.as_ref())
            .and_then(|inlay_hint_caps| inlay_hint_caps.resolve_support.as_ref())
            .map(|inlay_resolve| inlay_resolve.properties.iter())
            .into_iter()
            .flatten()
            .map(|s| s.as_str())
            .collect()
    }

    pub fn completion_resolve_support_properties(&self) -> FxHashSet<&str> {
        self.0
            .text_document
            .as_ref()
            .and_then(|text| text.completion.as_ref())
            .and_then(|completion_caps| completion_caps.completion_item.as_ref())
            .and_then(|completion_item_caps| completion_item_caps.resolve_support.as_ref())
            .map(|resolve_support| resolve_support.properties.iter())
            .into_iter()
            .flatten()
            .map(|s| s.as_str())
            .collect()
    }

    pub fn hover_markdown_support(&self) -> bool {
        (|| -> _ {
            Some(self.0.text_document.as_ref()?.hover.as_ref()?.content_format.as_ref()?.as_slice())
        })()
        .unwrap_or_default()
        .contains(&lsp_types::MarkupKind::Markdown)
    }

    pub fn insert_replace_support(&self) -> bool {
        (|| -> _ {
            self.0
                .text_document
                .as_ref()?
                .completion
                .as_ref()?
                .completion_item
                .as_ref()?
                .insert_replace_support
        })()
        .unwrap_or_default()
    }
}
