Implement support for settings

Settings are a flat "dictionary" containing
paths to settings on the format:

<category>.<sub-category>.<setting>.

1 files changed, 168 insertions, 0 deletions

diff --git a/src/settings.c b/src/settings.c
new file mode 100644
index 0000000..08e31d4
--- /dev/null
+++ b/src/settings.c
@@ -0,0 +1,168 @@
+#include "settings.h"
+#include "command.h"
+#include "hash.h"
+#include "minibuffer.h"
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+static struct settings g_settings = {0};
+
+void settings_resize(uint32_t new_capacity) {
+  if (new_capacity > g_settings.capacity) {
+    g_settings.settings =
+        realloc(g_settings.settings, sizeof(struct setting) * new_capacity);
+  }
+}
+
+void settings_init(uint32_t initial_capacity) {
+  settings_resize(initial_capacity);
+  g_settings.capacity = initial_capacity;
+  g_settings.nsettings = 0;
+}
+
+void settings_destroy() {
+  for (uint32_t i = 0; i < g_settings.nsettings; ++i) {
+    struct setting *setting = &g_settings.settings[i];
+    if (setting->value.type == Setting_String) {
+      free(setting->value.string_value);
+    }
+  }
+
+  free(g_settings.settings);
+  g_settings.settings = NULL;
+  g_settings.capacity = 0;
+  g_settings.nsettings = 0;
+}
+
+void settings_register_setting(const char *path,
+                               struct setting_value default_value) {
+  if (g_settings.nsettings + 1 == g_settings.capacity) {
+    g_settings.capacity *= 2;
+    settings_resize(g_settings.capacity);
+  }
+
+  struct setting *s = &g_settings.settings[g_settings.nsettings];
+  s->value = default_value;
+  s->hash = hash_name(path);
+  strncpy(s->path, path, 128);
+  s->path[127] = '\0';
+
+  ++g_settings.nsettings;
+}
+
+struct setting *settings_get(const char *path) {
+  uint32_t needle = hash_name(path);
+
+  for (uint32_t i = 0; i < g_settings.nsettings; ++i) {
+    struct setting *setting = &g_settings.settings[i];
+    if (setting->hash == needle) {
+      return setting;
+    }
+  }
+
+  return NULL;
+}
+
+void settings_get_prefix(const char *prefix, struct setting **settings_out[],
+                         uint32_t *nsettings_out) {
+
+  uint32_t capacity = 16;
+  struct setting **res = malloc(sizeof(struct setting *) * capacity);
+  uint32_t nsettings = 0;
+  for (uint32_t i = 0; i < g_settings.nsettings; ++i) {
+    struct setting *setting = &g_settings.settings[i];
+    if (strncmp(prefix, setting->path, strlen(prefix)) == 0) {
+      if (nsettings + 1 == capacity) {
+        capacity *= 2;
+        res = realloc(res, sizeof(struct setting *) * capacity);
+      }
+
+      res[nsettings] = setting;
+      ++nsettings;
+    }
+  }
+
+  *nsettings_out = nsettings;
+  *settings_out = res;
+}
+
+void settings_set(const char *path, struct setting_value value) {
+  struct setting *setting = settings_get(path);
+  if (setting != NULL && setting->value.type == value.type) {
+    setting->value = value;
+  }
+}
+
+void setting_to_string(struct setting *setting, char *buf, size_t n) {
+  switch (setting->value.type) {
+  case Setting_Bool:
+    snprintf(buf, n, "%s", setting->value.bool_value ? "true" : false);
+    break;
+  case Setting_Number:
+    snprintf(buf, n, "%ld", setting->value.number_value);
+    break;
+  case Setting_String:
+    snprintf(buf, n, "%s", setting->value.string_value);
+    break;
+  }
+}
+
+int32_t settings_get_cmd(struct command_ctx ctx, int argc, const char *argv[]) {
+  if (argc == 0) {
+    return minibuffer_prompt(ctx, "setting: ");
+  }
+
+  struct setting *setting = settings_get(argv[0]);
+  if (setting == NULL) {
+    minibuffer_echo_timeout(4, "no such setting \"%s\"", argv[0]);
+    return 1;
+  } else {
+    char buf[128];
+    setting_to_string(setting, buf, 128);
+    minibuffer_echo("%s = %s", argv[0], buf);
+  }
+
+  return 0;
+}
+
+int32_t settings_set_cmd(struct command_ctx ctx, int argc, const char *argv[]) {
+  if (argc == 0) {
+    return minibuffer_prompt(ctx, "setting: ");
+  } else if (argc == 1) {
+    // validate setting here as well
+    struct setting *setting = settings_get(argv[0]);
+    if (setting == NULL) {
+      minibuffer_echo_timeout(4, "no such setting \"%s\"", argv[0]);
+      return 1;
+    }
+
+    command_ctx_push_arg(&ctx, argv[0]);
+    return minibuffer_prompt(ctx, "value: ");
+  }
+
+  struct setting *setting = settings_get(argv[0]);
+  if (setting == NULL) {
+    minibuffer_echo_timeout(4, "no such setting \"%s\"", argv[0]);
+    return 1;
+  } else {
+    const char *value = argv[1];
+    struct setting_value new_value = {.type = setting->value.type};
+    switch (setting->value.type) {
+    case Setting_Bool:
+      new_value.bool_value = strncmp("true", value, 4) == 0;
+      break;
+    case Setting_Number:
+      new_value.number_value = atol(value);
+      break;
+    case Setting_String:
+      new_value.string_value = strdup(value);
+      break;
+    }
+
+    setting->value = new_value;
+  }
+
+  return 0;
+}