--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mrjunejune/conversation_store.c	Wed Aug 05 09:19:41 2026 -0700
@@ -0,0 +1,496 @@
+#include "mrjunejune/conversation_store.h"
+
+#include "deita/deita.h"
+
+#include <fcntl.h>
+#include <pthread.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+struct Conversation_Store {
+  Deita_Connection *p_connection;
+  pthread_mutex_t mutex;
+};
+
+boolean Conversation_Store_Generate_UUID(char output[37])
+{
+  uint8 bytes[16];
+  int fd = open("/dev/urandom", O_RDONLY);
+  if (fd < 0)
+    return FALSE;
+  size_t offset = 0;
+  while (offset < sizeof(bytes))
+  {
+    ssize_t amount = read(fd, bytes + offset, sizeof(bytes) - offset);
+    if (amount <= 0)
+    {
+      close(fd);
+      return FALSE;
+    }
+    offset += (size_t)amount;
+  }
+  close(fd);
+
+  bytes[6] = (uint8)((bytes[6] & 0x0f) | 0x40);
+  bytes[8] = (uint8)((bytes[8] & 0x3f) | 0x80);
+  snprintf(
+      output,
+      37,
+      "%02x%02x%02x%02x-%02x%02x-%02x%02x-%02x%02x-"
+      "%02x%02x%02x%02x%02x%02x",
+      bytes[0], bytes[1], bytes[2], bytes[3],
+      bytes[4], bytes[5], bytes[6], bytes[7],
+      bytes[8], bytes[9], bytes[10], bytes[11],
+      bytes[12], bytes[13], bytes[14], bytes[15]);
+  return TRUE;
+}
+
+static char *Conversation_Store_Copy_Text(
+    const char *value,
+    Dowa_Arena *p_arena)
+{
+  const char *source = value ? value : "";
+  size_t length = strlen(source);
+  char *copy = Dowa_Arena_Allocate(p_arena, length + 1);
+  if (!copy)
+    return NULL;
+  memcpy(copy, source, length + 1);
+  return copy;
+}
+
+static boolean Conversation_Store_Exists_Locked(
+    Conversation_Store *p_store,
+    const char *conversation_id)
+{
+  Dowa_Arena *p_arena = Dowa_Arena_Create(1024);
+  if (!p_arena)
+    return FALSE;
+  const char *parameters[] = {conversation_id};
+  Deita_Result_Set *p_result = Deita_Query_Execute_Prepared(
+      p_store->p_connection,
+      "SELECT 1 FROM conversations WHERE id = ? AND status != 'deleted'",
+      1,
+      parameters,
+      p_arena);
+  boolean exists = p_result && Deita_Result_Set_Next(p_result);
+  if (p_result)
+    Deita_Result_Set_Free(p_result);
+  Dowa_Arena_Free(p_arena);
+  return exists;
+}
+
+static Conversation_Store_Result Conversation_Store_Rollback(
+    Conversation_Store *p_store,
+    Conversation_Store_Result result)
+{
+  Deita_Query_Execute_Update(p_store->p_connection, "ROLLBACK");
+  return result;
+}
+
+Conversation_Store *Conversation_Store_Create(const char *database_path)
+{
+  if (!database_path)
+    return NULL;
+
+  Conversation_Store *p_store = calloc(1, sizeof(*p_store));
+  if (!p_store)
+    return NULL;
+  p_store->p_connection = Deita_Connection_Create(
+      DEITA_DATABASE_TYPE_SQLITE3,
+      database_path);
+  if (!p_store->p_connection ||
+      !Deita_Connection_Is_Open(p_store->p_connection))
+  {
+    if (p_store->p_connection)
+      Deita_Connection_Close(p_store->p_connection);
+    free(p_store);
+    return NULL;
+  }
+  if (pthread_mutex_init(&p_store->mutex, NULL) != 0)
+  {
+    Deita_Connection_Close(p_store->p_connection);
+    free(p_store);
+    return NULL;
+  }
+
+  const char *schema =
+      "PRAGMA foreign_keys = ON;"
+      "PRAGMA journal_mode = WAL;"
+      "CREATE TABLE IF NOT EXISTS conversations ("
+      "id TEXT PRIMARY KEY,"
+      "copilot_session_id TEXT NOT NULL UNIQUE,"
+      "title TEXT NOT NULL DEFAULT '',"
+      "status TEXT NOT NULL DEFAULT 'active',"
+      "created_at INTEGER NOT NULL DEFAULT (strftime('%s','now')),"
+      "updated_at INTEGER NOT NULL DEFAULT (strftime('%s','now'))"
+      ");"
+      "CREATE TABLE IF NOT EXISTS conversation_turns ("
+      "id INTEGER PRIMARY KEY AUTOINCREMENT,"
+      "conversation_id TEXT NOT NULL,"
+      "sequence INTEGER NOT NULL,"
+      "role TEXT NOT NULL,"
+      "content TEXT NOT NULL DEFAULT '',"
+      "status TEXT NOT NULL,"
+      "request_id TEXT,"
+      "error_message TEXT,"
+      "input_tokens INTEGER NOT NULL DEFAULT 0,"
+      "output_tokens INTEGER NOT NULL DEFAULT 0,"
+      "created_at INTEGER NOT NULL DEFAULT (strftime('%s','now')),"
+      "completed_at INTEGER,"
+      "FOREIGN KEY(conversation_id) REFERENCES conversations(id) "
+      "ON DELETE CASCADE,"
+      "UNIQUE(conversation_id, sequence)"
+      ");"
+      "CREATE UNIQUE INDEX IF NOT EXISTS "
+      "idx_conversation_active_request "
+      "ON conversation_turns(conversation_id) "
+      "WHERE role = 'assistant' AND status = 'active';"
+      "CREATE INDEX IF NOT EXISTS idx_conversations_updated "
+      "ON conversations(updated_at DESC);"
+      "CREATE INDEX IF NOT EXISTS idx_turns_conversation_sequence "
+      "ON conversation_turns(conversation_id, sequence);";
+  if (Deita_Query_Execute_Update(p_store->p_connection, schema) < 0)
+  {
+    Conversation_Store_Destroy(p_store);
+    return NULL;
+  }
+  if (Deita_Query_Execute_Update(
+          p_store->p_connection,
+          "UPDATE conversation_turns "
+          "SET status = 'failed', "
+          "error_message = 'Interrupted by server restart', "
+          "completed_at = strftime('%s','now') "
+          "WHERE role = 'assistant' AND status = 'active'") < 0)
+  {
+    Conversation_Store_Destroy(p_store);
+    return NULL;
+  }
+  return p_store;
+}
+
+void Conversation_Store_Destroy(Conversation_Store *p_store)
+{
+  if (!p_store)
+    return;
+  if (p_store->p_connection)
+    Deita_Connection_Close(p_store->p_connection);
+  pthread_mutex_destroy(&p_store->mutex);
+  free(p_store);
+}
+
+Conversation_Store_Result Conversation_Store_Create_Conversation(
+    Conversation_Store *p_store,
+    const char *title,
+    char output_id[37])
+{
+  if (!p_store || !output_id ||
+      !Conversation_Store_Generate_UUID(output_id))
+    return CONVERSATION_STORE_ERROR;
+
+  const char *parameters[] = {
+    output_id,
+    output_id,
+    title ? title : "",
+  };
+  pthread_mutex_lock(&p_store->mutex);
+  int32 result = Deita_Query_Execute_Update_Prepared(
+      p_store->p_connection,
+      "INSERT INTO conversations (id, copilot_session_id, title) "
+      "VALUES (?, ?, ?)",
+      3,
+      parameters);
+  pthread_mutex_unlock(&p_store->mutex);
+  return result < 0 ? CONVERSATION_STORE_ERROR : CONVERSATION_STORE_OK;
+}
+
+Conversation_Store_Result Conversation_Store_Get(
+    Conversation_Store *p_store,
+    const char *conversation_id,
+    Conversation_Record *p_record,
+    Dowa_Arena *p_arena)
+{
+  if (!p_store || !conversation_id || !p_record || !p_arena)
+    return CONVERSATION_STORE_ERROR;
+  memset(p_record, 0, sizeof(*p_record));
+
+  const char *parameters[] = {conversation_id};
+  pthread_mutex_lock(&p_store->mutex);
+  Deita_Result_Set *p_result = Deita_Query_Execute_Prepared(
+      p_store->p_connection,
+      "SELECT id, copilot_session_id, title, status, created_at, updated_at "
+      "FROM conversations WHERE id = ? AND status != 'deleted'",
+      1,
+      parameters,
+      p_arena);
+  if (!p_result || !Deita_Result_Set_Next(p_result))
+  {
+    if (p_result)
+      Deita_Result_Set_Free(p_result);
+    pthread_mutex_unlock(&p_store->mutex);
+    return CONVERSATION_STORE_NOT_FOUND;
+  }
+  p_record->id = Conversation_Store_Copy_Text(
+      Deita_Result_Set_Get_Text(p_result, 0), p_arena);
+  p_record->copilot_session_id = Conversation_Store_Copy_Text(
+      Deita_Result_Set_Get_Text(p_result, 1), p_arena);
+  p_record->title = Conversation_Store_Copy_Text(
+      Deita_Result_Set_Get_Text(p_result, 2), p_arena);
+  p_record->status = Conversation_Store_Copy_Text(
+      Deita_Result_Set_Get_Text(p_result, 3), p_arena);
+  p_record->created_at = Deita_Result_Set_Get_Integer(p_result, 4);
+  p_record->updated_at = Deita_Result_Set_Get_Integer(p_result, 5);
+  Deita_Result_Set_Free(p_result);
+
+  p_result = Deita_Query_Execute_Prepared(
+      p_store->p_connection,
+      "SELECT id, sequence, role, content, status, request_id, "
+      "error_message, input_tokens, output_tokens, created_at, completed_at "
+      "FROM (SELECT id, sequence, role, content, status, request_id, "
+      "error_message, input_tokens, output_tokens, created_at, completed_at "
+      "FROM conversation_turns WHERE conversation_id = ? "
+      "ORDER BY sequence DESC LIMIT 20) ORDER BY sequence",
+      1,
+      parameters,
+      p_arena);
+  if (!p_result)
+  {
+    pthread_mutex_unlock(&p_store->mutex);
+    return CONVERSATION_STORE_ERROR;
+  }
+  while (p_result && Deita_Result_Set_Next(p_result))
+  {
+    Conversation_Turn turn = {0};
+    turn.id = Deita_Result_Set_Get_Integer(p_result, 0);
+    turn.sequence = Deita_Result_Set_Get_Integer(p_result, 1);
+    turn.role = Conversation_Store_Copy_Text(
+        Deita_Result_Set_Get_Text(p_result, 2), p_arena);
+    turn.content = Conversation_Store_Copy_Text(
+        Deita_Result_Set_Get_Text(p_result, 3), p_arena);
+    turn.status = Conversation_Store_Copy_Text(
+        Deita_Result_Set_Get_Text(p_result, 4), p_arena);
+    turn.request_id = Conversation_Store_Copy_Text(
+        Deita_Result_Set_Get_Text(p_result, 5), p_arena);
+    turn.error_message = Conversation_Store_Copy_Text(
+        Deita_Result_Set_Get_Text(p_result, 6), p_arena);
+    turn.input_tokens = Deita_Result_Set_Get_Integer(p_result, 7);
+    turn.output_tokens = Deita_Result_Set_Get_Integer(p_result, 8);
+    turn.created_at = Deita_Result_Set_Get_Integer(p_result, 9);
+    turn.completed_at = Deita_Result_Set_Get_Integer(p_result, 10);
+    Dowa_Array_Push_Arena(p_record->turns, turn, p_arena);
+  }
+  boolean turns_error = Deita_Result_Set_Has_Error(p_result);
+  if (p_result)
+    Deita_Result_Set_Free(p_result);
+  pthread_mutex_unlock(&p_store->mutex);
+  return turns_error ? CONVERSATION_STORE_ERROR : CONVERSATION_STORE_OK;
+}
+
+Conversation_Store_Result Conversation_Store_Update_Title(
+    Conversation_Store *p_store,
+    const char *conversation_id,
+    const char *title)
+{
+  if (!p_store || !conversation_id || !title)
+    return CONVERSATION_STORE_ERROR;
+  const char *parameters[] = {title, conversation_id};
+  pthread_mutex_lock(&p_store->mutex);
+  int32 result = Deita_Query_Execute_Update_Prepared(
+      p_store->p_connection,
+      "UPDATE conversations SET title = ?, "
+      "updated_at = strftime('%s','now') "
+      "WHERE id = ? AND status != 'deleted'",
+      2,
+      parameters);
+  pthread_mutex_unlock(&p_store->mutex);
+  if (result < 0)
+    return CONVERSATION_STORE_ERROR;
+  return result == 0 ? CONVERSATION_STORE_NOT_FOUND : CONVERSATION_STORE_OK;
+}
+
+Conversation_Store_Result Conversation_Store_Delete(
+    Conversation_Store *p_store,
+    const char *conversation_id)
+{
+  if (!p_store || !conversation_id)
+    return CONVERSATION_STORE_ERROR;
+  const char *parameters[] = {conversation_id};
+  pthread_mutex_lock(&p_store->mutex);
+  int32 result = Deita_Query_Execute_Update_Prepared(
+      p_store->p_connection,
+      "DELETE FROM conversations WHERE id = ?",
+      1,
+      parameters);
+  pthread_mutex_unlock(&p_store->mutex);
+  if (result < 0)
+    return CONVERSATION_STORE_ERROR;
+  return result == 0 ? CONVERSATION_STORE_NOT_FOUND : CONVERSATION_STORE_OK;
+}
+
+Conversation_Store_Result Conversation_Store_Begin_Turn(
+    Conversation_Store *p_store,
+    const char *conversation_id,
+    const char *request_id,
+    const char *prompt)
+{
+  if (!p_store || !conversation_id || !request_id || !prompt)
+    return CONVERSATION_STORE_ERROR;
+
+  pthread_mutex_lock(&p_store->mutex);
+  if (Deita_Query_Execute_Update(
+          p_store->p_connection, "BEGIN IMMEDIATE") < 0)
+  {
+    pthread_mutex_unlock(&p_store->mutex);
+    return CONVERSATION_STORE_ERROR;
+  }
+  if (!Conversation_Store_Exists_Locked(p_store, conversation_id))
+  {
+    Conversation_Store_Rollback(
+        p_store, CONVERSATION_STORE_NOT_FOUND);
+    pthread_mutex_unlock(&p_store->mutex);
+    return CONVERSATION_STORE_NOT_FOUND;
+  }
+
+  Dowa_Arena *p_arena = Dowa_Arena_Create(2048);
+  const char *parameters[] = {conversation_id};
+  Deita_Result_Set *p_result = Deita_Query_Execute_Prepared(
+      p_store->p_connection,
+      "SELECT COALESCE(MAX(sequence), 0), "
+      "SUM(CASE WHEN role = 'assistant' AND status = 'active' "
+      "THEN 1 ELSE 0 END) "
+      "FROM conversation_turns WHERE conversation_id = ?",
+      1,
+      parameters,
+      p_arena);
+  if (!p_result || !Deita_Result_Set_Next(p_result))
+  {
+    if (p_result)
+      Deita_Result_Set_Free(p_result);
+    Dowa_Arena_Free(p_arena);
+    Conversation_Store_Rollback(p_store, CONVERSATION_STORE_ERROR);
+    pthread_mutex_unlock(&p_store->mutex);
+    return CONVERSATION_STORE_ERROR;
+  }
+  int64 next_sequence = Deita_Result_Set_Get_Integer(p_result, 0) + 1;
+  int64 active_count = Deita_Result_Set_Get_Integer(p_result, 1);
+  Deita_Result_Set_Free(p_result);
+  Dowa_Arena_Free(p_arena);
+  if (active_count > 0)
+  {
+    Conversation_Store_Rollback(p_store, CONVERSATION_STORE_CONFLICT);
+    pthread_mutex_unlock(&p_store->mutex);
+    return CONVERSATION_STORE_CONFLICT;
+  }
+
+  char user_sequence[32];
+  char assistant_sequence[32];
+  snprintf(user_sequence, sizeof(user_sequence), "%lld",
+           (long long)next_sequence);
+  snprintf(assistant_sequence, sizeof(assistant_sequence), "%lld",
+           (long long)(next_sequence + 1));
+  const char *user_parameters[] = {
+    conversation_id, user_sequence, prompt, request_id,
+  };
+  if (Deita_Query_Execute_Update_Prepared(
+          p_store->p_connection,
+          "INSERT INTO conversation_turns "
+          "(conversation_id, sequence, role, content, status, request_id, "
+          "completed_at) VALUES (?, ?, 'user', ?, 'complete', ?, "
+          "strftime('%s','now'))",
+          4,
+          user_parameters) < 0)
+  {
+    Conversation_Store_Rollback(p_store, CONVERSATION_STORE_ERROR);
+    pthread_mutex_unlock(&p_store->mutex);
+    return CONVERSATION_STORE_ERROR;
+  }
+  const char *assistant_parameters[] = {
+    conversation_id, assistant_sequence, request_id,
+  };
+  if (Deita_Query_Execute_Update_Prepared(
+          p_store->p_connection,
+          "INSERT INTO conversation_turns "
+          "(conversation_id, sequence, role, status, request_id) "
+          "VALUES (?, ?, 'assistant', 'active', ?)",
+          3,
+          assistant_parameters) < 0 ||
+      Deita_Query_Execute_Update_Prepared(
+          p_store->p_connection,
+          "UPDATE conversations SET updated_at = strftime('%s','now') "
+          "WHERE id = ?",
+          1,
+          parameters) < 0 ||
+      Deita_Query_Execute_Update(
+          p_store->p_connection, "COMMIT") < 0)
+  {
+    Conversation_Store_Rollback(p_store, CONVERSATION_STORE_ERROR);
+    pthread_mutex_unlock(&p_store->mutex);
+    return CONVERSATION_STORE_ERROR;
+  }
+  pthread_mutex_unlock(&p_store->mutex);
+  return CONVERSATION_STORE_OK;
+}
+
+Conversation_Store_Result Conversation_Store_Complete_Turn(
+    Conversation_Store *p_store,
+    const char *conversation_id,
+    const char *request_id,
+    const char *content,
+    int64 input_tokens,
+    int64 output_tokens)
+{
+  if (!p_store || !conversation_id || !request_id || !content)
+    return CONVERSATION_STORE_ERROR;
+  char input_value[32];
+  char output_value[32];
+  snprintf(input_value, sizeof(input_value), "%lld", (long long)input_tokens);
+  snprintf(output_value, sizeof(output_value), "%lld", (long long)output_tokens);
+  const char *parameters[] = {
+    content, input_value, output_value, conversation_id, request_id,
+  };
+  pthread_mutex_lock(&p_store->mutex);
+  int32 result = Deita_Query_Execute_Update_Prepared(
+      p_store->p_connection,
+      "UPDATE conversation_turns SET content = ?, status = 'complete', "
+      "input_tokens = ?, output_tokens = ?, "
+      "completed_at = strftime('%s','now') "
+      "WHERE conversation_id = ? AND request_id = ? "
+      "AND role = 'assistant' AND status = 'active'",
+      5,
+      parameters);
+  pthread_mutex_unlock(&p_store->mutex);
+  if (result < 0)
+    return CONVERSATION_STORE_ERROR;
+  return result == 0 ? CONVERSATION_STORE_NOT_FOUND : CONVERSATION_STORE_OK;
+}
+
+Conversation_Store_Result Conversation_Store_Fail_Turn(
+    Conversation_Store *p_store,
+    const char *conversation_id,
+    const char *request_id,
+    const char *error_message,
+    boolean aborted)
+{
+  if (!p_store || !conversation_id || !request_id)
+    return CONVERSATION_STORE_ERROR;
+  const char *parameters[] = {
+    aborted ? "aborted" : "failed",
+    error_message ? error_message : "",
+    conversation_id,
+    request_id,
+  };
+  pthread_mutex_lock(&p_store->mutex);
+  int32 result = Deita_Query_Execute_Update_Prepared(
+      p_store->p_connection,
+      "UPDATE conversation_turns SET status = ?, error_message = ?, "
+      "completed_at = strftime('%s','now') "
+      "WHERE conversation_id = ? AND request_id = ? "
+      "AND role = 'assistant' AND status = 'active'",
+      4,
+      parameters);
+  pthread_mutex_unlock(&p_store->mutex);
+  if (result < 0)
+    return CONVERSATION_STORE_ERROR;
+  return result == 0 ? CONVERSATION_STORE_NOT_FOUND : CONVERSATION_STORE_OK;
+}