import type * as lsp from "vscode-languageserver-protocol"
import { EditorView, Command, KeyBinding } from "@codemirror/view"
import { LSPPlugin } from "@codemirror/lsp-client";

import { addEditor } from "../editorgrid";
import { OpenFile } from "../filestate";

function getDefinition(plugin: LSPPlugin, pos: number) {
    return plugin.client.request<lsp.DefinitionParams, lsp.Location | lsp.Location[] | null>("textDocument/definition", {
        textDocument: { uri: plugin.uri },
        position: plugin.toPosition(pos)
    })
}

function getDeclaration(plugin: LSPPlugin, pos: number) {
    return plugin.client.request<lsp.DeclarationParams, lsp.Location | lsp.Location[] | null>("textDocument/declaration", {
        textDocument: { uri: plugin.uri },
        position: plugin.toPosition(pos)
    })
}

function getTypeDefinition(plugin: LSPPlugin, pos: number) {
    return plugin.client.request<lsp.TypeDefinitionParams, lsp.Location | lsp.Location[] | null>("textDocument/typeDefinition", {
        textDocument: { uri: plugin.uri },
        position: plugin.toPosition(pos)
    })
}

function getImplementation(plugin: LSPPlugin, pos: number) {
    return plugin.client.request<lsp.ImplementationParams, lsp.Location | lsp.Location[] | null>("textDocument/implementation", {
        textDocument: { uri: plugin.uri },
        position: plugin.toPosition(pos)
    })
}

function jumpToOrigin(view: EditorView, type: { get: typeof getDefinition, capability: keyof lsp.ServerCapabilities }): boolean {
    const plugin = LSPPlugin.get(view);
    const hasCapability = plugin.client.serverCapabilities ? !!plugin.client.serverCapabilities[type.capability] : null;
    if (!plugin || !hasCapability) return false
    plugin.client.sync()
    plugin.client.withMapping(mapping => type.get(plugin, view.state.selection.main.head).then(async response => {
        if (!response) return
        let loc = Array.isArray(response) ? response[0] : response;
        const path = new URL(loc.uri).pathname;
        const target = addEditor(await OpenFile.openFile(path));
        const pos = mapping.getMapping(loc.uri) ? mapping.mapPosition(loc.uri, loc.range.start) : plugin.fromPosition(loc.range.start, target.view.state.doc);
        target.view.dispatch({selection: {anchor: pos}, scrollIntoView: true, userEvent: "select.definition"});
    }, error => plugin.reportError("Find definition failed", error)))
    return true
}

/// Jump to the definition of the symbol at the cursor. To support
/// cross-file jumps, you'll need to implement
/// [`Workspace.displayFile`](#lsp-client.Workspace.displayFile).
export const jumpToDefinition: Command = view => jumpToOrigin(view, {
    get: getDefinition,
    capability: "definitionProvider"
})

/// Jump to the declaration of the symbol at the cursor.
export const jumpToDeclaration: Command = view => jumpToOrigin(view, {
    get: getDeclaration,
    capability: "declarationProvider"
})

/// Jump to the type definition of the symbol at the cursor.
export const jumpToTypeDefinition: Command = view => jumpToOrigin(view, {
    get: getTypeDefinition,
    capability: "typeDefinitionProvider"
})

/// Jump to the implementation of the symbol at the cursor.
export const jumpToImplementation: Command = view => jumpToOrigin(view, {
    get: getImplementation,
    capability: "implementationProvider"
})

/// Binds F12 to [`jumpToDefinition`](#lsp-client.jumpToDefinition).
export const jumpToDefinitionKeymap: readonly KeyBinding[] = [
    { key: "F12", run: jumpToDefinition, preventDefault: true },
]