1 files changed, 405 insertions, 0 deletions
diff --git a/src/main/lsp/completion.c b/src/main/lsp/completion.c
new file mode 100644
index 0000000..df89255
--- /dev/null
+++ b/src/main/lsp/completion.c
@@ -0,0 +1,405 @@
+#include "completion.h"
+
+#include <stddef.h>
+
+#include "dged/s8.h"
+#include "dged/vec.h"
+#include "types.h"
+
+#include "dged/buffer.h"
+#include "dged/buffer_view.h"
+#include "dged/minibuffer.h"
+#include "main/completion.h"
+#include "main/lsp.h"
+
+struct completion_ctx {
+  struct lsp_server *server;
+  struct completion_context comp_ctx;
+  struct completion_list completions;
+  struct s8 cached_with;
+  struct completion *completion_data;
+  uint64_t last_request;
+
+  triggerchar_vec trigger_chars;
+};
+
+struct symbol {
+  struct s8 symbol;
+  struct region region;
+};
+
+static struct symbol current_symbol(struct buffer *buffer, struct location at) {
+  struct region word = buffer_word_at(buffer, at);
+  if (!region_has_size(word)) {
+    return (struct symbol){
+        .symbol =
+            (struct s8){
+                .s = NULL,
+                .l = 0,
+            },
+        .region = word,
+    };
+  };
+
+  struct text_chunk line = buffer_region(buffer, region_new(word.begin, at));
+  struct s8 symbol = s8new((const char *)line.text, line.nbytes);
+
+  if (line.allocated) {
+    free(line.text);
+  }
+
+  return (struct symbol){.symbol = symbol, .region = word};
+}
+
+struct completion_ctx *create_completion_ctx(struct lsp_server *server,
+                                             triggerchar_vec *trigger_chars) {
+  struct completion_ctx *ctx =
+      (struct completion_ctx *)calloc(1, sizeof(struct completion_ctx));
+
+  ctx->server = server;
+  ctx->completion_data = NULL;
+  ctx->completions.incomplete = false;
+  ctx->cached_with.s = NULL;
+  ctx->cached_with.l = 0;
+  VEC_INIT(&ctx->completions.items, 0);
+
+  VEC_INIT(&ctx->trigger_chars, VEC_SIZE(trigger_chars));
+  VEC_FOR_EACH(trigger_chars, struct s8 * s) {
+    VEC_PUSH(&ctx->trigger_chars, s8dup(*s));
+  }
+
+  return ctx;
+}
+
+void destroy_completion_ctx(struct completion_ctx *ctx) {
+  completion_list_free(&ctx->completions);
+
+  if (ctx->completion_data != NULL) {
+    free(ctx->completion_data);
+  }
+
+  s8delete(ctx->cached_with);
+
+  VEC_FOR_EACH(&ctx->trigger_chars, struct s8 * s) { s8delete(*s); }
+  VEC_DESTROY(&ctx->trigger_chars);
+
+  free(ctx);
+}
+
+static char *item_kind_to_str(enum completion_item_kind kind) {
+  switch (kind) {
+  case CompletionItem_Text:
+    return "tx";
+
+  case CompletionItem_Method:
+    return "mth";
+
+  case CompletionItem_Function:
+    return "fn";
+
+  case CompletionItem_Constructor:
+    return "cons";
+
+  case CompletionItem_Field:
+    return "field";
+
+  case CompletionItem_Variable:
+    return "var";
+
+  case CompletionItem_Class:
+    return "cls";
+
+  case CompletionItem_Interface:
+    return "iface";
+
+  case CompletionItem_Module:
+    return "mod";
+
+  case CompletionItem_Property:
+    return "prop";
+
+  case CompletionItem_Unit:
+    return "unit";
+
+  case CompletionItem_Value:
+    return "val";
+
+  case CompletionItem_Enum:
+    return "enum";
+
+  case CompletionItem_Keyword:
+    return "kw";
+
+  case CompletionItem_Snippet:
+    return "snp";
+
+  case CompletionItem_Color:
+    return "col";
+
+  case CompletionItem_File:
+    return "file";
+
+  case CompletionItem_Reference:
+    return "ref";
+
+  case CompletionItem_Folder:
+    return "fld";
+
+  case CompletionItem_EnumMember:
+    return "em";
+
+  case CompletionItem_Constant:
+    return "const";
+
+  case CompletionItem_Struct:
+    return "struct";
+
+  case CompletionItem_Event:
+    return "ev";
+
+  case CompletionItem_Operator:
+    return "op";
+
+  case CompletionItem_TypeParameter:
+    return "tp";
+
+  default:
+    return "";
+  }
+}
+
+static struct region lsp_item_render(void *data, struct buffer *buffer) {
+  struct lsp_completion_item *item = (struct lsp_completion_item *)data;
+  struct location begin = buffer_end(buffer);
+  struct s8 kind_str = s8from_fmt("(%s)", item_kind_to_str(item->kind));
+  struct s8 txt = s8from_fmt("%-8.*s%.*s", kind_str.l, kind_str.s,
+                             item->label.l, item->label.s);
+  struct location end = buffer_add(buffer, begin, txt.s, txt.l);
+  s8delete(txt);
+  s8delete(kind_str);
+  buffer_newline(buffer, buffer_end(buffer));
+
+  return region_new(begin, end);
+}
+
+static void lsp_item_selected(void *data, struct buffer_view *view) {
+  struct lsp_completion_item *item = (struct lsp_completion_item *)data;
+  struct buffer *buffer = view->buffer;
+  struct lsp_server *lsp_server = lsp_server_for_buffer(buffer);
+
+  abort_completion();
+
+  if (lsp_server == NULL) {
+    return;
+  }
+
+  switch (item->edit_type) {
+  case TextEdit_None: {
+    struct symbol symbol = current_symbol(buffer, view->dot);
+    struct s8 insert = item->insert_text;
+
+    // FIXME: why does this happen?
+    if (symbol.symbol.l >= insert.l) {
+      s8delete(symbol.symbol);
+      return;
+    }
+
+    if (symbol.symbol.l > 0) {
+      insert.s += symbol.symbol.l;
+      insert.l -= symbol.symbol.l;
+    }
+
+    s8delete(symbol.symbol);
+
+    struct location at = buffer_add(buffer, view->dot, insert.s, insert.l);
+    buffer_view_goto(view, at);
+
+  } break;
+  case TextEdit_TextEdit: {
+    struct text_edit *ed = &item->edit.text_edit;
+    struct region reg = lsp_range_to_coordinates(lsp_server, buffer, ed->range);
+    struct location at = reg.begin;
+    if (!region_is_inside(reg, view->dot)) {
+      reg.end = view->dot;
+    }
+
+    if (region_has_size(reg)) {
+      at = buffer_delete(buffer, reg);
+    }
+
+    at = buffer_add(buffer, at, ed->new_text.s, ed->new_text.l);
+    buffer_view_goto(view, at);
+  } break;
+
+  case TextEdit_InsertReplaceEdit: {
+    struct insert_replace_edit *ed = &item->edit.insert_replace_edit;
+    struct region reg =
+        lsp_range_to_coordinates(lsp_server, buffer, ed->replace);
+
+    if (!region_is_inside(reg, view->dot)) {
+      reg.end = view->dot;
+    }
+
+    if (region_has_size(reg)) {
+      buffer_delete(buffer, reg);
+    }
+
+    struct location at =
+        buffer_add(buffer, ed->insert.begin, ed->new_text.s, ed->new_text.l);
+    buffer_view_goto(view, at);
+  } break;
+  }
+
+  if (!VEC_EMPTY(&item->additional_text_edits)) {
+    apply_edits_buffer(lsp_server, view->buffer, item->additional_text_edits,
+                       &view->dot);
+  }
+}
+
+static void lsp_item_cleanup(void *data) { (void)data; }
+
+static struct s8 get_filter_text(struct lsp_completion_item *item) {
+  return item->filter_text.l > 0 ? item->filter_text : item->label;
+}
+
+static void fill_completions(struct completion_ctx *lsp_ctx, struct s8 needle) {
+  if (lsp_ctx->completion_data != NULL) {
+    free(lsp_ctx->completion_data);
+    lsp_ctx->completion_data = NULL;
+  }
+
+  size_t ncomps = VEC_SIZE(&lsp_ctx->completions.items);
+
+  // if there is more than a single item or the user has not typed that
+  // single item exactly, then add to the list of completions.
+  lsp_ctx->completion_data = calloc(ncomps, sizeof(struct completion));
+
+  ncomps = 0;
+  VEC_FOR_EACH(&lsp_ctx->completions.items,
+               struct lsp_completion_item * lsp_item) {
+    struct s8 filter_text = get_filter_text(lsp_item);
+    if (needle.l == 0 || s8startswith(filter_text, needle)) {
+      struct completion *c = &lsp_ctx->completion_data[ncomps];
+
+      c->data = lsp_item;
+      c->render = lsp_item_render;
+      c->selected = lsp_item_selected;
+      c->cleanup = lsp_item_cleanup;
+      ++ncomps;
+    }
+  }
+
+  // if there is only a single item that matches the needle exactly,
+  // don't add it to the list since the user has already won
+  if (ncomps == 1 && needle.l > 0 &&
+      s8eq(get_filter_text(lsp_ctx->completion_data[0].data), needle)) {
+    return;
+  }
+
+  if (ncomps > 0) {
+    lsp_ctx->comp_ctx.add_completions(lsp_ctx->completion_data, ncomps);
+  }
+}
+
+static void handle_completion_response(struct lsp_server *server,
+                                       struct lsp_response *response,
+                                       void *userdata) {
+  (void)server;
+  struct completion_ctx *lsp_ctx = (struct completion_ctx *)userdata;
+
+  if (response->id != lsp_ctx->last_request) {
+    // discard any old requests
+    return;
+  }
+
+  completion_list_free(&lsp_ctx->completions);
+  lsp_ctx->completions = completion_list_from_json(&response->value.result);
+
+  fill_completions(lsp_ctx, lsp_ctx->cached_with);
+}
+
+static void complete_with_lsp(struct completion_context ctx, bool deletion,
+                              void *userdata) {
+  (void)deletion;
+  struct completion_ctx *lsp_ctx = (struct completion_ctx *)userdata;
+  lsp_ctx->comp_ctx = ctx;
+
+  struct symbol sym = current_symbol(ctx.buffer, ctx.location);
+  struct s8 symbol = sym.symbol;
+
+  // check if the symbol is too short for triggering completion
+  bool should_activate =
+      (symbol.l >= 3 || completion_active()) && !s8onlyws(symbol);
+
+  // use trigger chars as an alternative activation condition
+  if (!should_activate) {
+    struct location begin = buffer_previous_char(ctx.buffer, ctx.location);
+    struct location end = begin;
+    end.col += 4;
+    struct text_chunk txt = buffer_region(ctx.buffer, region_new(begin, end));
+    struct s8 t = {
+        .s = txt.text,
+        .l = txt.nbytes,
+    };
+
+    VEC_FOR_EACH(&lsp_ctx->trigger_chars, struct s8 * tc) {
+      if (s8startswith(t, *tc)) {
+        should_activate = true;
+        goto done;
+      }
+    }
+  done:
+    if (txt.allocated) {
+      free(txt.text);
+    }
+  }
+
+  // if we still should not activate, we give up
+  if (!should_activate) {
+    s8delete(symbol);
+    return;
+  }
+
+  bool has_completions = !VEC_EMPTY(&lsp_ctx->completions.items);
+  if (completion_active() && has_completions &&
+      !lsp_ctx->completions.incomplete && !s8empty(lsp_ctx->cached_with) &&
+      s8startswith(symbol, lsp_ctx->cached_with)) {
+    fill_completions(lsp_ctx, symbol);
+  } else {
+    uint64_t id = new_pending_request(lsp_ctx->server,
+                                      handle_completion_response, lsp_ctx);
+    lsp_ctx->last_request = id;
+
+    struct versioned_text_document_identifier doc =
+        versioned_identifier_from_buffer(ctx.buffer);
+    struct text_document_position params = {
+        .uri = doc.uri,
+        .position = ctx.location,
+    };
+
+    s8delete(lsp_ctx->cached_with);
+    lsp_ctx->cached_with = s8dup(symbol);
+
+    struct s8 json_payload = document_position_to_json(&params);
+    lsp_send(
+        lsp_backend(lsp_ctx->server),
+        lsp_create_request(id, s8("textDocument/completion"), json_payload));
+
+    versioned_text_document_identifier_free(&doc);
+    s8delete(json_payload);
+  }
+
+  s8delete(symbol);
+}
+
+void enable_completion_for_buffer(struct completion_ctx *ctx,
+                                  struct buffer *buffer) {
+  struct completion_provider prov = {
+      .name = "lsp",
+      .complete = complete_with_lsp,
+      .userdata = ctx,
+  };
+  struct completion_provider providers[] = {prov};
+
+  add_completion_providers(buffer, providers, 1);
+}