more refactors

8 files changed, 382 insertions, 266 deletions

diff --git a/include/administration.hpp b/include/administration.hpp
index 219ece0..3415b3a 100644
--- a/include/administration.hpp
+++ b/include/administration.hpp
@@ -20,18 +20,20 @@
 #define MAX_LEN_BUSINESSID      32
 #define MAX_LEN_TAX_SECTION     16
 
+#define MAX_BILLING_ITEMS       50
+
 typedef struct
 {
-    char id[MAX_LEN_ID];
-    char country_code[MAX_LEN_COUNTRY_CODE];
-    float rate; // 0-100
-    char description[MAX_LEN_SHORT_DESC];
+    char id[MAX_LEN_ID]; // T/[id]
+    char country_code[MAX_LEN_COUNTRY_CODE]; // 2 letter country code
+    float rate; // 0-100%
+    char description[MAX_LEN_SHORT_DESC]; // Currently only used for global tax brackets
 } country_tax_bracket;
 
 typedef struct
 {
-    char id[MAX_LEN_ID];
-    char code[MAX_LEN_CODE];
+    char id[MAX_LEN_ID]; // C/[id]
+    char code[MAX_LEN_CODE]; // Internal 4 letter code
     char description[MAX_LEN_LONG_DESC];
 } cost_center;
 
@@ -39,7 +41,7 @@ typedef struct
 {
     char address1[MAX_LEN_ADDRESS];
     char address2[MAX_LEN_ADDRESS];
-    char country_code[MAX_LEN_COUNTRY_CODE]; // 2 letter country code.
+    char country_code[MAX_LEN_COUNTRY_CODE]; // 2 letter country code
 } address;
 
 typedef enum
@@ -50,12 +52,12 @@ typedef enum
 
 typedef struct
 {
-    char id[MAX_LEN_ID];
+    char id[MAX_LEN_ID]; // C/[id]
     char name[MAX_LEN_LONG_DESC];
     address address;
     contact_type type;
-    char taxid[MAX_LEN_TAXID];
-    char businessid[MAX_LEN_TAXID];
+    char taxid[MAX_LEN_TAXID]; // Required for business contact
+    char businessid[MAX_LEN_TAXID]; // Required for business contact
     char email[MAX_LEN_EMAIL];
     char phone_number[MAX_LEN_PHONE];
     char bank_account[MAX_LEN_BANK];
@@ -70,11 +72,11 @@ typedef enum
 
 typedef struct
 {
-    char id[MAX_LEN_ID];
+    char id[MAX_LEN_ID]; // P/[id]
     char description[MAX_LEN_LONG_DESC];
     project_state state;
     time_t start_date;
-    time_t end_date;
+    time_t end_date; // Set when project is cancelled
 } project;
 
 typedef enum
@@ -91,8 +93,8 @@ typedef enum
 
 typedef struct
 {
-    char id[MAX_LEN_ID];
-    char invoice_id[MAX_LEN_ID];
+    char id[MAX_LEN_ID]; // B/[id]
+    char invoice_id[MAX_LEN_ID]; // I/[id]
     float amount;
     bool amount_is_percentage;
     char description[MAX_LEN_LONG_DESC];
@@ -100,21 +102,21 @@ typedef struct
     float discount;
     bool discount_is_percentage;
     float net;
-    char currency[MAX_LEN_CURRENCY];
-    char tax_bracket_id[MAX_LEN_ID];
+    char currency[MAX_LEN_CURRENCY]; // 3 letter code
+    char tax_bracket_id[MAX_LEN_ID]; // T/[id]
     float tax;
     float total;
     
-    // todo
+    // TODO uninplemented
     char tax_section[MAX_LEN_TAX_SECTION];
 } billing_item;
 
 typedef struct
 {
-    char id[MAX_LEN_ID];
+    char id[MAX_LEN_ID]; // I/[id]
     char sequential_number[MAX_LEN_SEQ_NUM]; // INV0000000000 - INV9999999999
-    char customer_id[MAX_LEN_ID];
-    char supplier_id[MAX_LEN_ID];
+    char customer_id[MAX_LEN_ID]; // C/[id]
+    char supplier_id[MAX_LEN_ID]; // C/[id]
     contact addressee;
     time_t issued_at;
     time_t expires_at;
@@ -129,14 +131,14 @@ typedef struct
     float tax;
     float net;
 
-    char currency[MAX_LEN_CURRENCY];
+    char currency[MAX_LEN_CURRENCY]; // 3 letter code
     bool is_triangulation; // True of addressee != customer
     invoice_status status;
     
-    bool is_intra_community; // TODO
-    time_t payment_on_account_date; // TODO
-    char tax_representative[MAX_LEN_LONG_DESC]; // TODO
-    char corrected_sequential_number[MAX_LEN_ID]; // TODO
+    bool is_intra_community; // TODO uninplemented
+    time_t payment_on_account_date; // TODO uninplemented
+    char tax_representative[MAX_LEN_LONG_DESC]; // TODO uninplemented
+    char corrected_sequential_number[MAX_LEN_ID]; // TODO uninplemented
 
     // Used for forms, not stored on disk. Filled when retrieved.
     contact supplier;
@@ -179,7 +181,9 @@ bool    administration_contact_remove(contact data);
 
 bool    administration_contact_is_valid(contact data);
 bool    administration_contact_can_be_deleted(contact data);
+bool    administration_contact_equals(contact c1, contact c2);
 
+bool    administration_contact_get_by_id(contact* buffer, char* id);
 int     administration_contact_get_autocompletions(contact* buffer, int buf_size, char* name);
 u32     administration_contact_get_partial_list(u32 page_index, u32 page_size, contact* buffer);
 
@@ -224,6 +228,7 @@ u32     administration_invoice_count();
 invoice administration_invoice_create_empty();
 bool    administration_invoice_add(invoice* invoice);
 bool    administration_invoice_update(invoice* invoice);
+bool    administration_invoice_remove(invoice* invoice);
 void    administration_invoice_set_currency(invoice* invoice, char* currency);
 invoice administration_invoice_create_copy(invoice* invoice);
 
@@ -234,7 +239,7 @@ u32     administration_invoice_get_partial_list(u32 page_index, u32 page_size, i
 
 // Billing item functions.
 // =======================
-u32     administration_billing_items_count(invoice* invoice);
+u32     administration_billing_item_count(invoice* invoice);
 billing_item administration_billing_item_create_empty();
 bool    administration_billing_item_add_to_invoice(invoice* invoice, billing_item item);
 bool    administration_billing_item_update_in_invoice(invoice* invoice, billing_item item);
diff --git a/include/ui.hpp b/include/ui.hpp
index 67e0529..a594095 100644
--- a/include/ui.hpp
+++ b/include/ui.hpp
@@ -21,5 +21,8 @@ void ui_setup_contacts();
 void ui_setup_projects();
 void ui_setup_settings();
 
+void ui_destroy_invoices();
+void ui_destroy_settings();
+
 // Custom imgui widgets.
 int TextInputWithAutocomplete(const char* label, const char* hint, char* buffer, size_t buf_size, char** suggestions, int suggestion_count);
\ No newline at end of file
diff --git a/src/administration.cpp b/src/administration.cpp
index 4d8233e..ace1383 100644
--- a/src/administration.cpp
+++ b/src/administration.cpp
@@ -264,14 +264,29 @@ static void administration_create_debug_data()
     ADD_PROJECT("Kayak rental");
 
     // Company info.
+    
+    snprintf(g_administration.company_info.id, sizeof(g_administration.company_info.id), "C/%d", administration_create_id());
     strops_copy(g_administration.company_info.name, "Aldrik Ramaekers", sizeof(g_administration.company_info.name));
     strops_copy(g_administration.company_info.address.address1, "Keerderstraat 81", sizeof(g_administration.company_info.address.address1));
     strops_copy(g_administration.company_info.address.address2, "6226XW Maastricht", sizeof(g_administration.company_info.address.address2));
     strops_copy(g_administration.company_info.address.country_code, "NL", sizeof(g_administration.company_info.address.country_code));
     strops_copy(g_administration.company_info.taxid, "123", sizeof(g_administration.company_info.taxid));
     strops_copy(g_administration.company_info.businessid, "123", sizeof(g_administration.company_info.businessid));
+    g_administration.next_id++;
+}
+
+static s32 administration_create_sequence_number()
+{
+    return g_administration.next_sequence_number;
 }
 
+static time_t administration_get_default_invoice_expire_duration()
+{
+    return (30 * 24 * 60 * 60); // 30 days
+}
+
+// Setup functions.
+// =======================
 void administration_create()
 {
     g_administration.next_id = 1;
@@ -284,23 +299,50 @@ void administration_create()
     list_init(&g_administration.cost_centers);
     strops_copy(g_administration.path, "", sizeof(g_administration.path));
 
-    snprintf(g_administration.company_info.id, sizeof(g_administration.company_info.id), "C/%d", administration_create_id());
-    g_administration.next_id++;
-
     administration_create_default_tax_brackets();
     administration_create_default_cost_centers();
     administration_create_debug_data();
 }
 
+static void administration_destroy_list(list_t *list)
+{
+    list_iterator_start(list);
+    while (list_iterator_hasnext(list)) {
+        void* c = (void *)list_iterator_next(list);
+        free(c);
+    }
+    list_iterator_stop(list);
+    list_destroy(list);
+}
+
 void administration_destroy()
 {
-    list_destroy(&g_administration.invoices);
-    list_destroy(&g_administration.contacts);
-    list_destroy(&g_administration.projects);
-    list_destroy(&g_administration.tax_brackets);
-    list_destroy(&g_administration.cost_centers);
+    administration_destroy_list(&g_administration.invoices);
+    administration_destroy_list(&g_administration.contacts);
+    administration_destroy_list(&g_administration.projects);
+    administration_destroy_list(&g_administration.tax_brackets);
+    administration_destroy_list(&g_administration.cost_centers);
 }
 
+// General functions.
+// =======================
+char* administration_file_path_get()
+{
+    return g_administration.path;
+}
+
+contact administration_company_info_get()
+{
+    return g_administration.company_info;
+}
+
+void administration_company_info_set(contact data)
+{
+    g_administration.company_info = data;
+}
+
+// Contact functions.
+// =======================
 bool administration_contact_add(contact data)
 {
     if (!administration_contact_is_valid(data)) return false;
@@ -349,6 +391,7 @@ bool administration_contact_remove(contact data)
         if (strcmp(c->id, data.id) == 0) {      
             list_iterator_stop(&g_administration.contacts);
             list_delete(&g_administration.contacts, c);
+            free(c);
             return true;
         }
     }
@@ -384,6 +427,24 @@ u32 administration_contact_get_partial_list(u32 page_index, u32 page_size, conta
     return write_cursor;
 }
 
+bool administration_contact_get_by_id(contact* buffer, char* id)
+{
+    bool result = false;
+    list_iterator_start(&g_administration.contacts);
+    while (list_iterator_hasnext(&g_administration.contacts)) {
+        contact c = *(contact *)list_iterator_next(&g_administration.contacts);
+
+        if (strcmp(c.id, id) == 0) {
+            list_iterator_stop(&g_administration.projects);
+            *buffer = c;
+            result = true;
+        }
+    }
+    list_iterator_stop(&g_administration.contacts);
+
+    return result;
+}
+
 int administration_contact_get_autocompletions(contact* buffer, int buf_size, char* name)
 {
     int write_cursor = 0;
@@ -403,33 +464,39 @@ int administration_contact_get_autocompletions(contact* buffer, int buf_size, ch
     return write_cursor;
 }
 
-char* administration_file_path_get()
+bool administration_contact_is_valid(contact data)
 {
-    return g_administration.path;
+    if (data.type == contact_type::CONTACT_CONSUMER)
+    {
+        return strlen(data.name) > 0 && strlen(data.address.address1) > 0 && strlen(data.address.address2) > 0 && strlen(data.address.country_code) > 0;
+    }
+    else if (data.type == contact_type::CONTACT_BUSINESS)
+    {
+        return strlen(data.name) > 0 && strlen(data.address.address1) > 0 && strlen(data.address.address2) > 0 && strlen(data.address.country_code) > 0
+                && strlen(data.taxid) > 0 && strlen(data.businessid);
+    }
+
+    return false;
 }
 
-u32 administration_project_count()
+contact administration_contact_create_empty()
 {
-    return list_size(&g_administration.projects);
+    contact result;
+    memset(&result, 0, sizeof(contact));
+    snprintf(result.id, sizeof(result.id), "C/%d", administration_create_id());
+    return result;
 }
 
-u32 administration_billing_items_count(invoice* invoice)
+bool administration_contact_equals(contact c1, contact c2)
 {
-    return list_size(&invoice->billing_items);
+    return memcmp(&c1, &c2, sizeof(contact)) == 0;
 }
 
-u32 administration_billing_item_get_all_for_invoice(invoice* invoice, billing_item* buffer)
+// Project functions.
+// =======================
+u32 administration_project_count()
 {
-    u32 write_cursor = 0;
-    
-    list_iterator_start(&invoice->billing_items);
-    while (list_iterator_hasnext(&invoice->billing_items)) {
-        billing_item c = *(billing_item *)list_iterator_next(&invoice->billing_items);
-        buffer[write_cursor++] = c;
-    }
-    list_iterator_stop(&invoice->billing_items);
-
-    return write_cursor;
+    return list_size(&g_administration.projects);
 }
 
 u32 administration_project_get_all(project* buffer)
@@ -480,23 +547,6 @@ bool administration_project_is_valid(project data)
     return strlen(data.description) > 0;
 }
 
-char* administration_invoice_get_status_string(invoice* invoice)
-{
-    switch(invoice->status)
-    {
-        case invoice_status::INVOICE_CONCEPT: return "invoice.state.concept";
-        case invoice_status::INVOICE_SENT: return "invoice.state.sent";
-        case invoice_status::INVOICE_REMINDED: return "invoice.state.reminded";
-        case invoice_status::INVOICE_PAID: return "invoice.state.paid";
-        case invoice_status::INVOICE_EXPIRED: return "invoice.state.expired";
-        case invoice_status::INVOICE_CANCELLED: return "invoice.state.cancelled";
-        case invoice_status::INVOICE_REFUNDED: return "invoice.state.refunded";
-        case invoice_status::INVOICE_CORRECTED: return "invoice.state.corrected";
-        default: assert(0); break;
-    }
-    return "";
-}
-
 char* administration_project_get_status_string(project data)
 {
     switch(data.state)
@@ -553,6 +603,7 @@ bool administration_project_remove(project data)
         if (strcmp(c->id, data.id) == 0) {      
             list_iterator_stop(&g_administration.projects);
             list_delete(&g_administration.projects, c);
+            free(c);
             return true;
         }
     }
@@ -561,14 +612,33 @@ bool administration_project_remove(project data)
     return false;
 }
 
-contact administration_company_info_get()
+project administration_project_create_empty()
 {
-    return g_administration.company_info;
+    project result;
+    memset(&result, 0, sizeof(project));
+    snprintf(result.id, sizeof(result.id), "P/%d", administration_create_id());
+    return result;
 }
 
-void administration_company_info_set(contact data)
+// Tax bracket functions.
+// =======================
+static bool administration_get_tax_bracket_by_id(country_tax_bracket* buffer, char* id)
 {
-    g_administration.company_info = data;
+    assert(buffer);
+
+    list_iterator_start(&g_administration.tax_brackets);
+    while (list_iterator_hasnext(&g_administration.tax_brackets)) {
+        country_tax_bracket c = *(country_tax_bracket *)list_iterator_next(&g_administration.tax_brackets);
+        if (strcmp(c.id, id) == 0)
+        {
+            *buffer = c;
+            list_iterator_stop(&g_administration.tax_brackets);
+            return true;
+        }
+    }
+    list_iterator_stop(&g_administration.tax_brackets);
+
+    return false;
 }
 
 u32 administration_tax_bracket_count()
@@ -634,6 +704,8 @@ bool administration_tax_bracket_update(country_tax_bracket data)
     return false;
 }
 
+// Cost center functions.
+// =======================
 u32 administration_cost_center_count()
 {
     return list_size(&g_administration.cost_centers);
@@ -720,52 +792,8 @@ bool administration_cost_center_update(cost_center data)
     return false;
 }
 
-bool administration_contact_is_valid(contact data)
-{
-    if (data.type == contact_type::CONTACT_CONSUMER)
-    {
-        return strlen(data.name) > 0 && strlen(data.address.address1) > 0 && strlen(data.address.address2) > 0 && strlen(data.address.country_code) > 0;
-    }
-    else if (data.type == contact_type::CONTACT_BUSINESS)
-    {
-        return strlen(data.name) > 0 && strlen(data.address.address1) > 0 && strlen(data.address.address2) > 0 && strlen(data.address.country_code) > 0
-                && strlen(data.taxid) > 0 && strlen(data.businessid);
-    }
-
-    return false;
-}
-
-static s32 administration_create_sequence_number()
-{
-    return g_administration.next_sequence_number;
-}
-
-static time_t administration_get_default_invoice_expire_duration()
-{
-    return (30 * 24 * 60 * 60); // 30 days
-}
-
-billing_item administration_billing_item_create_empty()
-{
-    billing_item item;
-    memset(&item, 0, sizeof(billing_item));
-    item.amount = 1;
-    return item;
-}
-
-bool administration_billing_item_add_to_invoice(invoice* invoice, billing_item item)
-{
-    billing_item* tb = (billing_item*)malloc(sizeof(billing_item));
-    memcpy(tb, &item, sizeof(billing_item));
-    snprintf(tb->id, sizeof(tb->id), "B/%d", administration_create_id());
-    strops_copy(tb->invoice_id, invoice->id, sizeof(tb->invoice_id));
-    list_append(&invoice->billing_items, tb);
-    strops_copy(tb->currency, invoice->currency, MAX_LEN_CURRENCY); // Set billing item currency to invoice currency.
-
-    g_administration.next_id++;
-
-    return true;
-}
+// Invoice functions.
+// =======================
 
 static char* administration_get_default_currency_for_country(char* country_code)
 {
@@ -821,41 +849,6 @@ invoice administration_invoice_create_empty()
     return result;
 }
 
-contact administration_contact_create_empty()
-{
-    contact result;
-    memset(&result, 0, sizeof(contact));
-    snprintf(result.id, sizeof(result.id), "C/%d", administration_create_id());
-    return result;
-}
-
-project administration_project_create_empty()
-{
-    project result;
-    memset(&result, 0, sizeof(project));
-    snprintf(result.id, sizeof(result.id), "P/%d", administration_create_id());
-    return result;
-}
-
-static bool administration_get_tax_bracket_by_id(country_tax_bracket* buffer, char* id)
-{
-    assert(buffer);
-
-    list_iterator_start(&g_administration.tax_brackets);
-    while (list_iterator_hasnext(&g_administration.tax_brackets)) {
-        country_tax_bracket c = *(country_tax_bracket *)list_iterator_next(&g_administration.tax_brackets);
-        if (strcmp(c.id, id) == 0)
-        {
-            *buffer = c;
-            list_iterator_stop(&g_administration.tax_brackets);
-            return true;
-        }
-    }
-    list_iterator_stop(&g_administration.tax_brackets);
-
-    return false;
-}
-
 static void administration_recalculate_invoice_totals(invoice* invoice)
 {
     invoice->tax = 0.0f;
@@ -873,75 +866,6 @@ static void administration_recalculate_invoice_totals(invoice* invoice)
     list_iterator_stop(&invoice->billing_items);
 }
 
-static void administration_recalculate_billing_item_totals(billing_item* item)
-{
-    if (item->amount_is_percentage)
-    {
-        item->net = item->net_per_item * (item->amount / 100.0f);
-    }
-    else
-    {
-        item->net = item->net_per_item * item->amount;
-    }
-
-    if (item->discount != 0)
-    {
-        if (item->discount_is_percentage)
-        {
-            item->net -= item->net * (item->discount / 100.0f);
-        }
-        else
-        {
-            item->net -= item->discount;
-        }
-    }
-
-    country_tax_bracket bracket;
-    if (administration_get_tax_bracket_by_id(&bracket, item->tax_bracket_id))
-    {
-        item->tax = item->net * (bracket.rate/100.0f);
-    }
-
-    item->total = item->net + item->tax;
-}
-
-bool administration_billing_item_remove_from_invoice(invoice* invoice, billing_item item)
-{
-    list_iterator_start(&invoice->billing_items);
-    while (list_iterator_hasnext(&invoice->billing_items)) {
-        billing_item* c = (billing_item *)list_iterator_next(&invoice->billing_items);
-
-        if (strcmp(c->id, item.id) == 0) {
-            list_iterator_stop(&invoice->billing_items);
-            list_delete(&invoice->billing_items, c);
-            return true;
-        }
-    }
-    list_iterator_stop(&invoice->billing_items);
-
-    return false;
-}
-
-bool administration_billing_item_update_in_invoice(invoice* invoice, billing_item item)
-{
-    list_iterator_start(&invoice->billing_items);
-    while (list_iterator_hasnext(&invoice->billing_items)) {
-        billing_item* c = (billing_item *)list_iterator_next(&invoice->billing_items);
-
-        if (strcmp(c->id, item.id) == 0) {
-            memcpy(c, &item, sizeof(billing_item));      
-            list_iterator_stop(&invoice->billing_items);
-
-            administration_recalculate_billing_item_totals(c);
-            administration_recalculate_invoice_totals(invoice);
-            return true;
-        }
-    }
-    list_iterator_stop(&invoice->billing_items);
-
-    return false;
-}
-
 void administration_invoice_set_currency(invoice* invoice, char* currency)
 {
     strops_copy(invoice->currency, currency, MAX_LEN_CURRENCY);
@@ -965,6 +889,25 @@ bool administration_invoice_is_valid(invoice* invoice)
     return true;
 }
 
+bool administration_invoice_remove(invoice* inv)
+{
+    list_iterator_start(&g_administration.invoices);
+    while (list_iterator_hasnext(&g_administration.invoices)) {
+        invoice* c = (invoice *)list_iterator_next(&g_administration.invoices);
+
+        if (strcmp(c->id, inv->id) == 0)
+        {
+            list_iterator_stop(&g_administration.invoices);
+            administration_destroy_list(&c->billing_items);
+            list_delete(&g_administration.invoices, c);
+            free(c);
+            return true;
+        }
+    }
+    list_iterator_stop(&g_administration.invoices);
+    return false;
+}
+
 bool administration_invoice_update(invoice* inv)
 {
     if (!administration_invoice_is_valid(inv)) return false;
@@ -1084,4 +1027,137 @@ u32 administration_invoice_get_partial_list(u32 page_index, u32 page_size, invoi
     list_iterator_stop(&g_administration.invoices);
 
     return write_cursor;
+}
+
+char* administration_invoice_get_status_string(invoice* invoice)
+{
+    switch(invoice->status)
+    {
+        case invoice_status::INVOICE_CONCEPT: return "invoice.state.concept";
+        case invoice_status::INVOICE_SENT: return "invoice.state.sent";
+        case invoice_status::INVOICE_REMINDED: return "invoice.state.reminded";
+        case invoice_status::INVOICE_PAID: return "invoice.state.paid";
+        case invoice_status::INVOICE_EXPIRED: return "invoice.state.expired";
+        case invoice_status::INVOICE_CANCELLED: return "invoice.state.cancelled";
+        case invoice_status::INVOICE_REFUNDED: return "invoice.state.refunded";
+        case invoice_status::INVOICE_CORRECTED: return "invoice.state.corrected";
+        default: assert(0); break;
+    }
+    return "";
+}
+
+// Billing item functions.
+// =======================
+
+static void administration_recalculate_billing_item_totals(billing_item* item)
+{
+    if (item->amount_is_percentage)
+    {
+        item->net = item->net_per_item * (item->amount / 100.0f);
+    }
+    else
+    {
+        item->net = item->net_per_item * item->amount;
+    }
+
+    if (item->discount != 0)
+    {
+        if (item->discount_is_percentage)
+        {
+            item->net -= item->net * (item->discount / 100.0f);
+        }
+        else
+        {
+            item->net -= item->discount;
+        }
+    }
+
+    country_tax_bracket bracket;
+    if (administration_get_tax_bracket_by_id(&bracket, item->tax_bracket_id))
+    {
+        item->tax = item->net * (bracket.rate/100.0f);
+    }
+
+    item->total = item->net + item->tax;
+}
+
+u32 administration_billing_item_count(invoice* invoice)
+{
+    return list_size(&invoice->billing_items);
+}
+
+u32 administration_billing_item_get_all_for_invoice(invoice* invoice, billing_item* buffer)
+{
+    u32 write_cursor = 0;
+    
+    list_iterator_start(&invoice->billing_items);
+    while (list_iterator_hasnext(&invoice->billing_items)) {
+        billing_item c = *(billing_item *)list_iterator_next(&invoice->billing_items);
+        buffer[write_cursor++] = c;
+    }
+    list_iterator_stop(&invoice->billing_items);
+
+    return write_cursor;
+}
+
+bool administration_billing_item_remove_from_invoice(invoice* invoice, billing_item item)
+{
+    list_iterator_start(&invoice->billing_items);
+    while (list_iterator_hasnext(&invoice->billing_items)) {
+        billing_item* c = (billing_item *)list_iterator_next(&invoice->billing_items);
+
+        if (strcmp(c->id, item.id) == 0) {
+            list_iterator_stop(&invoice->billing_items);
+            list_delete(&invoice->billing_items, c);
+            free(c);
+            return true;
+        }
+    }
+    list_iterator_stop(&invoice->billing_items);
+
+    return false;
+}
+
+bool administration_billing_item_update_in_invoice(invoice* invoice, billing_item item)
+{
+    list_iterator_start(&invoice->billing_items);
+    while (list_iterator_hasnext(&invoice->billing_items)) {
+        billing_item* c = (billing_item *)list_iterator_next(&invoice->billing_items);
+
+        if (strcmp(c->id, item.id) == 0) {
+            memcpy(c, &item, sizeof(billing_item));      
+            list_iterator_stop(&invoice->billing_items);
+
+            administration_recalculate_billing_item_totals(c);
+            administration_recalculate_invoice_totals(invoice);
+            return true;
+        }
+    }
+    list_iterator_stop(&invoice->billing_items);
+
+    return false;
+}
+
+bool administration_billing_item_add_to_invoice(invoice* invoice, billing_item item)
+{
+    if (administration_billing_item_count(invoice) >= MAX_BILLING_ITEMS) return false;
+
+    billing_item* tb = (billing_item*)malloc(sizeof(billing_item));
+    memcpy(tb, &item, sizeof(billing_item));
+    snprintf(tb->id, sizeof(tb->id), "B/%d", administration_create_id());
+    strops_copy(tb->invoice_id, invoice->id, sizeof(tb->invoice_id));
+    list_append(&invoice->billing_items, tb);
+    strops_copy(tb->currency, invoice->currency, MAX_LEN_CURRENCY); // Set billing item currency to invoice currency.
+
+    g_administration.next_id++;
+
+    return true;
+}
+
+billing_item administration_billing_item_create_empty()
+{
+    billing_item item;
+    memset(&item, 0, sizeof(billing_item));
+    item.amount = 1;
+    return item;
 }
\ No newline at end of file
diff --git a/src/ui/helpers.cpp b/src/ui/helpers.cpp
index 7bde384..6ca1bd2 100644
--- a/src/ui/helpers.cpp
+++ b/src/ui/helpers.cpp
@@ -59,6 +59,7 @@ int TextInputWithAutocomplete(const char* label, const char* hint, char* buffer,
 
             for (int i = 0; i < suggestion_count; ++i)
             {
+                ImGui::PushID(i);
                 if (ImGui::Selectable(suggestions[i]))
                 {
                     // Copy selected suggestion to buffer
@@ -67,6 +68,7 @@ int TextInputWithAutocomplete(const char* label, const char* hint, char* buffer,
                     result = i;
                     is_open = false;
                 }
+                ImGui::PopID();
             }
 
             ImGui::EndChild();
diff --git a/src/ui/ui_contacts.cpp b/src/ui/ui_contacts.cpp
index a55fd73..dbe6625 100644
--- a/src/ui/ui_contacts.cpp
+++ b/src/ui/ui_contacts.cpp
@@ -1,4 +1,5 @@
 #include <stdio.h>
+#include <stdlib.h>
 
 #include "strops.hpp"
 #include "ui.hpp"
@@ -99,7 +100,8 @@ void draw_contact_form_ex(contact* buffer, bool viewing_only = false, bool with_
 
         for (int i = 0; i < autocomplete_count; i++)
         {
-            autocomplete_strings[i] = autocomplete_list[i].name;
+            autocomplete_strings[i] = (char*)malloc(200);
+            snprintf(autocomplete_strings[i], 200, "%s (%s %s)", autocomplete_list[i].name, autocomplete_list[i].address.address1, autocomplete_list[i].address.address2);
         }
 
         int autocomplete_index = TextInputWithAutocomplete(localize("contact.form.fullname"), localize("contact.form.fullname"), 
@@ -113,6 +115,11 @@ void draw_contact_form_ex(contact* buffer, bool viewing_only = false, bool with_
         {
             memcpy(buffer, &autocomplete_list[autocomplete_index], sizeof(contact));
         }
+
+        for (int i = 0; i < autocomplete_count; i++)
+        {
+            free(autocomplete_strings[i]);
+        }
     }
     else ImGui::InputTextWithHint(localize("contact.form.fullname"), localize("contact.form.fullname"), buffer->name, IM_ARRAYSIZE(buffer->name));
     ImGui::SameLine();ui_helper_draw_required_tag();
diff --git a/src/ui/ui_invoices.cpp b/src/ui/ui_invoices.cpp
index c08dd76..320392a 100644
--- a/src/ui/ui_invoices.cpp
+++ b/src/ui/ui_invoices.cpp
@@ -11,20 +11,25 @@
 #include "administration.hpp"
 #include "locales.hpp"
 
-void ui_draw_address_form(address* buffer);
 
 static view_state current_view_state = view_state::LIST;
 static invoice active_invoice = {0};
+static invoice selected_for_removal = {0};
 
 cost_center* cost_center_list_buffer = 0;
 country_tax_bracket* tax_bracket_list_buffer = 0;
+project* project_list_buffer = 0;
+billing_item* invoice_items_buffer = 0;
 
+void ui_draw_address_form(address* buffer);
 void draw_contact_form_ex(contact* buffer, bool viewing_only = false, bool with_autocomplete = false, bool* on_autocomplete = 0);
 
 void ui_destroy_invoices()
 {
     free(cost_center_list_buffer);
     free(tax_bracket_list_buffer);
+    free(project_list_buffer);
+    free(invoice_items_buffer);
 }
 
 void ui_setup_invoices()
@@ -33,10 +38,16 @@ void ui_setup_invoices()
     active_invoice = administration_invoice_create_empty();
 
     u32 costcenter_count = administration_cost_center_count();
-    cost_center_list_buffer = (cost_center*) malloc(sizeof(cost_center) * costcenter_count); // @leak
+    cost_center_list_buffer = (cost_center*) malloc(sizeof(cost_center) * costcenter_count);
 
     u32 tax_bracket_count = administration_tax_bracket_count();
-    tax_bracket_list_buffer = (country_tax_bracket*) malloc(sizeof(country_tax_bracket) * tax_bracket_count); // @leak
+    tax_bracket_list_buffer = (country_tax_bracket*) malloc(sizeof(country_tax_bracket) * tax_bracket_count);
+
+    u32 project_count = administration_project_count();
+    project_list_buffer = (project*) malloc(sizeof(project) * project_count);
+
+    u32 invoice_items_count = MAX_BILLING_ITEMS;
+    invoice_items_buffer = (billing_item*)malloc(sizeof(billing_item) * invoice_items_count);
 }
 
 void draw_tax_bracket_selector(char* tax_bracket_id)
@@ -185,10 +196,8 @@ void draw_costcenter_selector(char* costcenter_id)
 void draw_project_selector(char* project_id)
 {
     project* selected_project = NULL;
-
-    u32 project_count = administration_project_count();
-    project* buffer = (project*) malloc(sizeof(project) * project_count);
-    project_count = administration_project_get_all(buffer);
+    project* buffer = project_list_buffer;
+    u32 project_count = administration_project_get_all(buffer);
 
     // Select project by given id.
     if (strlen(project_id) > 0)
@@ -219,15 +228,12 @@ void draw_project_selector(char* project_id)
     if (selected_project_index != -1) {
         strops_copy(project_id, buffer[selected_project_index].id, MAX_LEN_ID);
     }
-
-    free(buffer);
 }
 
 static void draw_invoice_items_form(invoice* invoice)
 {
-    u32 invoice_items = administration_billing_items_count(invoice);
-    billing_item* buffer = (billing_item*)malloc(sizeof(billing_item) * invoice_items);
-    administration_billing_item_get_all_for_invoice(invoice, buffer);
+    billing_item* buffer = invoice_items_buffer;
+    u32 invoice_items = administration_billing_item_get_all_for_invoice(invoice, buffer);
 
     if (ImGui::BeginTable("TableBillingItems", 9, ImGuiTableFlags_Borders | ImGuiTableFlags_RowBg)) {
 
@@ -343,8 +349,6 @@ static void draw_invoice_items_form(invoice* invoice)
 
         ImGui::EndTable();
     }
-
-    free(buffer);
 }
 
 static void draw_invoice_form(invoice* buffer, bool viewing_only = false)
@@ -396,12 +400,20 @@ static void draw_invoice_form(invoice* buffer, bool viewing_only = false)
     bool on_autocomplete;
     draw_contact_form_ex(&buffer->customer, false, true, &on_autocomplete);
 
-    // TODO: check if customer info is equal to contact stored in customer id, in case we select from dropdown and edit data after,
-    // this should be handled as a new contact and customer_id should be set to "" so we create a new contact.
-
     if (on_autocomplete) {
         strops_copy(buffer->customer_id, buffer->customer.id, sizeof(buffer->customer_id));
     }
+    
+    // Check if contact info is equal to contact stored in customer id, in case we select from dropdown and edit data after,
+    // this should be handled as a new contact and customer_id should be set to "" so we create a new contact.
+    contact lookup_buffer;
+    if (administration_contact_get_by_id(&lookup_buffer, buffer->customer_id))
+    {
+        if (!administration_contact_equals(lookup_buffer, buffer->customer))
+        {
+            buffer->customer_id[0] = '\0';
+        }
+    }
 
     // 8. (optional) shipping address.
     ImGui::Checkbox("Shipping information differs from billing information (triangulation)", &buffer->is_triangulation);
@@ -424,11 +436,14 @@ static void draw_invoice_form(invoice* buffer, bool viewing_only = false)
     ImGui::Spacing();
 
     // 11. New billing item button.
+    bool max_items_reached = administration_billing_item_count(buffer) >= MAX_BILLING_ITEMS;
+    if (max_items_reached) ImGui::BeginDisabled();
     if (ImGui::Button(localize("+ Billing item")))
     {
         billing_item item = administration_billing_item_create_empty();
         administration_billing_item_add_to_invoice(buffer, item);
     }
+    if (max_items_reached) ImGui::EndDisabled();
 
     // 12. Dropdown for invoice currency.
     ImGui::SameLine();
@@ -530,34 +545,31 @@ static void ui_draw_invoices_list()
                     active_invoice = administration_invoice_create_copy(&c); // We create a copy because of billing item list pointers.
                     current_view_state = view_state::EDIT;
                 }
+                
+                ImGui::SameLine();
+                snprintf(btn_name, sizeof(btn_name), "%s##%d", localize("form.delete"), i);
+                if (ImGui::Button(btn_name)) {
+                    selected_for_removal = c;
+                    ImGui::OpenPopup("ConfirmDeletePopup");
+                }
             }
-
-            // ImGui::SameLine();
-            // if (administration_contact_can_be_deleted(c))
-            // {
-            //     snprintf(btn_name, sizeof(btn_name), "%s##%d", localize("form.delete"), i);
-            //     if (ImGui::Button(btn_name)) {
-            //         selected_for_removal = c;
-            //         ImGui::OpenPopup("ConfirmDeletePopup");
-            //     }
-            // }
         }
 
         // Confirmation popup before contact is deleted definitively.
-        // if (ImGui::BeginPopupModal("ConfirmDeletePopup", nullptr, ImGuiWindowFlags_AlwaysAutoResize|ImGuiWindowFlags_NoMove|ImGuiWindowFlags_NoTitleBar)) {
-        //     ImGui::Text(localize("form.confirmDelete"));
-        //     ImGui::Separator();
-
-        //     if (ImGui::Button(localize("form.yes"), ImVec2(120, 0))) { 
-        //         administration_contact_remove(selected_for_removal);
-        //         ImGui::CloseCurrentPopup();
-        //     }
-        //     ImGui::SameLine();
-        //     if (ImGui::Button(localize("form.no"), ImVec2(120, 0))) {
-        //         ImGui::CloseCurrentPopup();
-        //     }
-        //     ImGui::EndPopup();
-        // }
+        if (ImGui::BeginPopupModal("ConfirmDeletePopup", nullptr, ImGuiWindowFlags_AlwaysAutoResize|ImGuiWindowFlags_NoMove|ImGuiWindowFlags_NoTitleBar)) {
+            ImGui::Text(localize("form.confirmDelete"));
+            ImGui::Separator();
+
+            if (ImGui::Button(localize("form.yes"), ImVec2(120, 0))) { 
+                administration_invoice_remove(&selected_for_removal);
+                ImGui::CloseCurrentPopup();
+            }
+            ImGui::SameLine();
+            if (ImGui::Button(localize("form.no"), ImVec2(120, 0))) {
+                ImGui::CloseCurrentPopup();
+            }
+            ImGui::EndPopup();
+        }
 
         ImGui::EndTable();
     }
diff --git a/src/ui/ui_main.cpp b/src/ui/ui_main.cpp
index d8fd5d4..19ab6b4 100644
--- a/src/ui/ui_main.cpp
+++ b/src/ui/ui_main.cpp
@@ -37,8 +37,19 @@ void (*setupcalls[dashboard_view_state::END])(void) = {
     ui_setup_settings,
 };
 
+void (*destroycalls[dashboard_view_state::END])(void) = {
+    ui_destroy_invoices,
+    0,
+    0,
+    0,
+    0,
+    ui_destroy_settings,
+    0,
+};
+
 static void set_dashboard_state(dashboard_view_state state)
 {
+    if (dashboard_state != dashboard_view_state::END && destroycalls[dashboard_state]) destroycalls[dashboard_state]();
     dashboard_state = state;
     if (setupcalls[dashboard_state]) setupcalls[dashboard_state]();
 }
diff --git a/src/ui/ui_settings.cpp b/src/ui/ui_settings.cpp
index 69c4f54..3f9ab6d 100644
--- a/src/ui/ui_settings.cpp
+++ b/src/ui/ui_settings.cpp
@@ -11,11 +11,11 @@ extern void draw_contact_form(contact* buffer, bool viewing_only = false);
 
 static contact company_info;
 
-country_tax_bracket* tax_brackets;
 u32 tax_bracket_count;
+country_tax_bracket* tax_brackets = 0;
 
-cost_center* cost_centers;
 u32 cost_center_count;
+cost_center* cost_centers = 0;
 
 void ui_destroy_settings()
 {