//! Advertizes the capabilities of the LSP Server.
use std::env;

use lsp_types::{
    CallHierarchyServerCapability, ClientCapabilities, CodeActionKind, CodeActionOptions,
    CodeActionProviderCapability, CodeLensOptions, CompletionOptions,
    DocumentOnTypeFormattingOptions, FileOperationFilter, FileOperationPattern,
    FileOperationPatternKind, FileOperationRegistrationOptions, FoldingRangeProviderCapability,
    HoverProviderCapability, ImplementationProviderCapability, OneOf, RenameOptions, SaveOptions,
    SelectionRangeProviderCapability, SemanticTokensFullOptions, SemanticTokensLegend,
    SemanticTokensOptions, ServerCapabilities, SignatureHelpOptions, TextDocumentSyncCapability,
    TextDocumentSyncKind, TextDocumentSyncOptions, TypeDefinitionProviderCapability,
    WorkDoneProgressOptions, WorkspaceFileOperationsServerCapabilities,
    WorkspaceServerCapabilities,
};
use serde_json::json;

use crate::semantic_tokens;

pub fn server_capabilities(client_caps: &ClientCapabilities) -> ServerCapabilities {
    ServerCapabilities {
        text_document_sync: Some(TextDocumentSyncCapability::Options(TextDocumentSyncOptions {
            open_close: Some(true),
            change: Some(if env::var("RA_NO_INCREMENTAL_SYNC").is_ok() {
                TextDocumentSyncKind::Full
            } else {
                TextDocumentSyncKind::Incremental
            }),
            will_save: None,
            will_save_wait_until: None,
            save: Some(SaveOptions::default().into()),
        })),
        hover_provider: Some(HoverProviderCapability::Simple(true)),
        completion_provider: Some(CompletionOptions {
            resolve_provider: completions_resolve_provider(client_caps),
            trigger_characters: Some(vec![":".to_string(), ".".to_string(), "'".to_string()]),
            all_commit_characters: None,
            completion_item: None,
            work_done_progress_options: WorkDoneProgressOptions { work_done_progress: None },
        }),
        signature_help_provider: Some(SignatureHelpOptions {
            trigger_characters: Some(vec!["(".to_string(), ",".to_string()]),
            retrigger_characters: None,
            work_done_progress_options: WorkDoneProgressOptions { work_done_progress: None },
        }),
        declaration_provider: None,
        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(code_action_capabilities(client_caps)),
        code_lens_provider: Some(CodeLensOptions { resolve_provider: Some(true) }),
        document_formatting_provider: Some(OneOf::Left(true)),
        document_range_formatting_provider: None,
        document_on_type_formatting_provider: Some(DocumentOnTypeFormattingOptions {
            first_trigger_character: "=".to_string(),
            more_trigger_character: Some(vec![".".to_string(), ">".to_string()]),
        }),
        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: None,
            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,
        experimental: Some(json!({
            "joinLines": true,
            "ssr": true,
            "onEnter": true,
            "parentModule": true,
            "runnables": {
                "kinds": [ "cargo" ],
            },
        })),
    }
}

fn completions_resolve_provider(client_caps: &ClientCapabilities) -> Option<bool> {
    if completion_item_edit_resolve(client_caps) {
        Some(true)
    } else {
        log::info!("No `additionalTextEdits` completion resolve capability was found in the client capabilities, autoimport completion is disabled");
        None
    }
}

/// Parses client capabilities and returns all completion resolve capabilities rust-analyzer supports.
pub(crate) fn completion_item_edit_resolve(caps: &ClientCapabilities) -> bool {
    (|| {
        Some(
            caps.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)
}

fn code_action_capabilities(client_caps: &ClientCapabilities) -> CodeActionProviderCapability {
    client_caps
        .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(),
            })
        })
}
