/*
* Copyright (c) 2025 Aldrik Ramaekers <aldrik.ramaekers@gmail.com>
* 
* Permission to use, copy, modify, and/or distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
* 
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/

#define _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
#include <time.h>

#include "ImGuiDatePicker/ImGuiDatePicker.hpp"
//#include "tinyfiledialogs/tinyfiledialogs.h"

#include "strops.hpp"
#include "ui.hpp"
#include "imgui.h"
#include "administration.hpp"
#include "administration_writer.hpp"
#include "locales.hpp"


static view_state current_view_state = view_state::LIST;
static invoice active_invoice = {0};
static invoice selected_for_removal = {0};

static billing_item* invoice_items_buffer = 0;

void draw_contact_form_ex(contact* buffer, bool viewing_only = false, bool with_autocomplete = false);
void draw_addressee_form_ex(delivery_info* buffer, bool viewing_only = false);

void ui_destroy_invoices()
{
    free(invoice_items_buffer);
}

void ui_setup_invoices()
{
    current_view_state = view_state::LIST;
    active_invoice = administration_invoice_create_empty();

    u32 invoice_items_count = MAX_BILLING_ITEMS;
    invoice_items_buffer = (billing_item*)malloc(sizeof(billing_item) * invoice_items_count);
}

void draw_invoice_items_form(invoice* invoice)
{
    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)) {

        ImGui::TableSetupColumn("##actions", ImGuiTableColumnFlags_WidthFixed, 20);
        ImGui::TableSetupColumn(localize("invoice.table.amount"), ImGuiTableColumnFlags_WidthFixed, 80);
        ImGui::TableSetupColumn(localize("invoice.table.description"));
        ImGui::TableSetupColumn(localize("invoice.table.price"), ImGuiTableColumnFlags_WidthFixed, 100);
        ImGui::TableSetupColumn(localize("invoice.table.discount"), ImGuiTableColumnFlags_WidthFixed, 100);
        ImGui::TableSetupColumn(localize("invoice.table.net"), ImGuiTableColumnFlags_WidthFixed, 100);
        ImGui::TableSetupColumn(localize("invoice.table.tax%"), ImGuiTableColumnFlags_WidthFixed, 120);
        ImGui::TableSetupColumn(localize("invoice.table.tax"), ImGuiTableColumnFlags_WidthFixed, 100);
        ImGui::TableSetupColumn(localize("invoice.table.total"), ImGuiTableColumnFlags_WidthFixed, 100);

        ImGui::TableHeadersRow();

        for (u32 i = 0; i < invoice_items; i++)
        {
            billing_item item = buffer[i];
            a_err valid = administration_billing_item_is_valid(item);

            ImGui::TableNextRow();
            
            ImGui::PushID(i);

            ImGui::TableSetColumnIndex(0);
            if (ImGui::Button("X"))
            {
                administration_billing_item_remove_from_invoice(invoice, item);
            }
            
            ImGui::TableSetColumnIndex(1); 
            ImGui::InputFloat("##amount", &item.amount, 0.0f, 0.0f, "%.0f");
            ImGui::SameLine();

            ImGui::FormToggleCombo(&item.amount_is_percentage, "X", "%");

            ImGui::TableSetColumnIndex(2); 
            ImGui::PushItemWidth(-1);
            ImGui::InputTextWithError("##desc", item.description, IM_ARRAYSIZE(item.description), valid & A_ERR_MISSING_DESCRIPTION);
            ImGui::PopItemWidth();

            ImGui::TableSetColumnIndex(3); 
            ImGui::PushItemWidth(-1);
            ImGui::InputFloat("##price", &item.net_per_item, 0.0f, 0.0f, "%.2f");
            ImGui::PopItemWidth();

            ImGui::TableSetColumnIndex(4); 
            ImGui::InputFloat("##discount", &item.discount, 0.0f, 0.0f, "%.2f");
            ImGui::SameLine();

            ImGui::FormToggleCombo(&item.discount_is_percentage, item.currency, "%");

            ImGui::TableSetColumnIndex(5); 
            ImGui::Text("%.2f %s", item.net, item.currency);

            ImGui::TableSetColumnIndex(6);
            ImGui::PushItemWidth(-1);
            ImGui::FormTaxRateCombo(item.tax_rate_id, invoice->customer.address.country_code, invoice->supplier.address.country_code, valid & A_ERR_MISSING_TAX_RATE);

            ImGui::PopItemWidth();

            ImGui::TableSetColumnIndex(7); 
            ImGui::Text("%.2f %s", item.tax, item.currency);

            ImGui::TableSetColumnIndex(8); 
            ImGui::Text("%.2f %s", item.total, item.currency);

            ImGui::PopID();

            administration_billing_item_update_in_invoice(invoice, item);
        }

        ImGui::TableNextRow();
        ImGui::TableSetBgColor(ImGuiTableBgTarget_RowBg0, IM_COL32(70, 70, 70, 255));

        ImGui::TableSetColumnIndex(5); 
        ImGui::Text("%.2f %s", invoice->orig_net, invoice->currency);

        ImGui::TableSetColumnIndex(7); 
        ImGui::Text("%.2f %s", invoice->orig_tax, invoice->currency);

        ImGui::TableSetColumnIndex(8); 
        ImGui::Text("%.2f %s", invoice->orig_total, invoice->currency);

        if (strcmp(invoice->currency, administration_get_default_currency()) != 0) {
            ImGui::TableNextRow();
            ImGui::TableSetBgColor(ImGuiTableBgTarget_RowBg0, IM_COL32(50, 50, 50, 255));

            ImGui::TableSetColumnIndex(2);
            ImGui::Text("%s %s", localize("invoice.form.finalSettlement"), administration_get_default_currency());

            ImGui::TableSetColumnIndex(4); 
            ImGui::InputFloat("##final_allowance", &invoice->allowance, 0.0f, 0.0f, "%.2f");
            ImGui::SameLine();
            ImGui::Text("%s", administration_get_default_currency());

            ImGui::TableSetColumnIndex(5); 
            ImGui::InputFloat("##final_net", &invoice->net, 0.0f, 0.0f, "%.2f");
            ImGui::SameLine();
            ImGui::Text("%s", administration_get_default_currency());

            ImGui::TableSetColumnIndex(7); 
            ImGui::InputFloat("##final_tax", &invoice->tax, 0.0f, 0.0f, "%.2f");
            ImGui::SameLine();
            ImGui::Text("%s", administration_get_default_currency());

            ImGui::TableSetColumnIndex(8); 
            ImGui::InputFloat("##final_total", &invoice->total, 0.0f, 0.0f, "%.2f");
            ImGui::SameLine();
            ImGui::Text("%s", administration_get_default_currency());
        }

        ImGui::EndTable();
    }
}

static void draw_invoice_form(invoice* buffer, bool viewing_only = false)
{
    ImGui::BeginDisabled();

    ImGui::Text("%s: %s", localize("invoice.form.invoicenumber"), buffer->sequential_number);
    ImGui::Text("%s: %s", localize("invoice.form.supplier"), buffer->supplier.name);

    tm issued_at_date = *gmtime(&buffer->issued_at);
    if (ImGui::DatePicker("##issuedAt", issued_at_date))
    {
        buffer->issued_at = mktime(&issued_at_date);
    }
    ImGui::SameLine();
    ImGui::Text(localize("invoice.form.issuedat"));

    tm expires_at_date = *gmtime(&buffer->expires_at);
    if (ImGui::DatePicker("##expiresAt", expires_at_date))
    {
        buffer->expires_at = mktime(&expires_at_date);
    }
    ImGui::SameLine();
    ImGui::Text(localize("invoice.form.expiresat"));
    if (!viewing_only) ImGui::EndDisabled();

    tm delivered_at_date = *gmtime(&buffer->delivered_at);
    if (ImGui::DatePicker("##deliveredAt", delivered_at_date))
    {
        buffer->delivered_at = mktime(&delivered_at_date);
    }
    ImGui::SameLine();
    ImGui::Text(localize("invoice.form.deliveredat"));

    ImGui::Separator();

    if (ImGui::FormFileSelector(buffer->document.original_path)) {
        buffer->document.copy_path[0] = 0;
    }

    ImGui::Separator();

    ImGui::Text(localize("invoice.form.billinginformation"));
    draw_contact_form_ex(&buffer->customer, false, true);

    ImGui::Checkbox(localize("invoice.form.triangulation"), &buffer->is_triangulation);
    if (buffer->is_triangulation) {
        ImGui::Spacing();
        ImGui::Text(localize("invoice.form.shippinginformation"));
        draw_addressee_form_ex(&buffer->addressee, 0);
    }
    ImGui::Separator();

    ImGui::FormProjectCombo(buffer->project_id);

    ImGui::Spacing();
    ImGui::Spacing();
    ImGui::Spacing();

    bool max_items_reached = administration_billing_item_count(buffer) >= MAX_BILLING_ITEMS;
    if (max_items_reached) ImGui::BeginDisabled();
    if (ImGui::Button(localize(localize("invoice.form.add"))))
    {
        billing_item item = administration_billing_item_create_empty();
        administration_billing_item_add_to_invoice(buffer, item);
    }
    if (max_items_reached) ImGui::EndDisabled();

    ImGui::SameLine();
    ImGui::Text("| %s: ", localize("invoice.form.currency"));
    ImGui::SameLine();
    if (ImGui::FormCurrencyCombo(buffer->currency))
    {
        administration_invoice_set_currency(buffer, buffer->currency);
    }

    draw_invoice_items_form(buffer);
    
    if (viewing_only) ImGui::EndDisabled();
}

static void ui_draw_invoices_list()
{
    if (!administration_can_create_invoices()) {
        ImGui::PushStyleColor(ImGuiCol_Text, IM_COL32(0, 102, 204, 255)); // blue
        ImGui::Text(localize("ui.invoiceRequirementP1"));
        ImGui::PopStyleColor();

        if (ImGui::IsItemHovered()) {
            ImGui::SetMouseCursor(ImGuiMouseCursor_Hand);
            if (ImGui::IsMouseClicked(ImGuiMouseButton_Left)) {
                ui_set_state(main_state::UI_SETTINGS);
            }
        }

        ImGui::SameLine();
        ImGui::Text(localize("ui.invoiceRequirementP2"));
        return;
    }

    const u32 items_per_page = 50;
    static s32 current_page = 0;

    invoice invoice_list[items_per_page];
    u32 invoice_count = administration_invoice_get_partial_list_outgoing(current_page, items_per_page, invoice_list);
    u32 total_invoice_count = administration_invoice_get_outgoing_count();

    s32 max_page = (total_invoice_count + items_per_page - 1) / items_per_page;
    if (max_page == 0) max_page = 1;

    // Table header controls: create button and pagination.
    if (ImGui::Button(localize("form.create")))
    {
        current_view_state = view_state::CREATE;
        active_invoice = administration_invoice_create_empty(); // @leak
        active_invoice.supplier = administration_company_info_get();
        active_invoice.is_outgoing = 1;
        active_invoice.status = invoice_status::INVOICE_CONCEPT;
    }

    if (current_page >= max_page-1) current_page = max_page-1;
    if (current_page < 0) current_page = 0;

    // Navigate to prev page button.
    ImGui::SameLine();
    bool enable_prev = current_page > 0;
    if (!enable_prev) ImGui::BeginDisabled();
    if (ImGui::Button(localize("ui.prev")) && current_page > 0) current_page--;
    if (!enable_prev) ImGui::EndDisabled();

    ImGui::SameLine();
    ImGui::Text("(%d/%d)", current_page+1, max_page);

    // Navigate to next page button.
    ImGui::SameLine();
    bool enable_next = current_page < max_page-1;
    if (!enable_next) ImGui::BeginDisabled();
    if (ImGui::Button(localize("ui.next")) && current_page < max_page-1) current_page++;
    if (!enable_next) ImGui::EndDisabled();

    ImGui::Spacing();

    if (ImGui::BeginTable("TableInvoices", 7, ImGuiTableFlags_Borders | ImGuiTableFlags_RowBg)) {

        ImGui::TableSetupColumn(localize("invoice.table.invoicenumber"), ImGuiTableColumnFlags_WidthFixed, 120);
        ImGui::TableSetupColumn(localize("invoice.table.customer"));
        ImGui::TableSetupColumn(localize("invoice.table.addressee"));
        ImGui::TableSetupColumn(localize("invoice.table.issuedat"));
        ImGui::TableSetupColumn(localize("invoice.table.total"));
        ImGui::TableSetupColumn(localize("invoice.table.status"));
        ImGui::TableSetupColumn("");
        ImGui::TableHeadersRow();     

        for (u32 i = 0; i < invoice_count; i++) {
            invoice c = invoice_list[i];
            
            ImGui::TableNextRow();
            ImGui::TableSetColumnIndex(0); ImGui::Text(c.sequential_number);
            ImGui::TableSetColumnIndex(1); ImGui::Text(c.customer.name);
            ImGui::TableSetColumnIndex(2); ImGui::Text(c.addressee.name);

            struct tm *lt = localtime(&c.issued_at);
            char buf[80];
            strftime(buf, sizeof(buf), "%d-%m-%Y", lt);

            ImGui::TableSetColumnIndex(3); ImGui::Text(buf);
            ImGui::TableSetColumnIndex(4); ImGui::Text("%.2f %s", c.total, c.currency);
            ImGui::TableSetColumnIndex(5); ImGui::Text("%s", localize(administration_invoice_get_status_string(&c)));
            ImGui::TableSetColumnIndex(6);
            
            char btn_name[20];
            snprintf(btn_name, sizeof(btn_name), "%s##%d", localize("form.view"), i);
            if (ImGui::Button(btn_name)) {
                active_invoice = c;
                current_view_state = view_state::VIEW;
            }

            ImGui::SameLine();

            if (c.status == invoice_status::INVOICE_CONCEPT)
            {
                snprintf(btn_name, sizeof(btn_name), "%s##%d", localize("form.change"), i);
                if (ImGui::Button(btn_name)) {
                    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");
                }
            }
        }

        // 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_invoice_remove(&selected_for_removal);
                ImGui::CloseCurrentPopup();
            }
            ImGui::SameLine();
            if (ImGui::Button(localize("form.no"), ImVec2(120, 0))) {
                ImGui::CloseCurrentPopup();
            }
            ImGui::EndPopup();
        }

        ImGui::EndTable();
    }
}


static void ui_draw_invoice_update()
{
    if (ImGui::Button(localize("form.back"))) {
        current_view_state = view_state::LIST;
    }
    
    draw_invoice_form(&active_invoice);

    bool can_save = administration_invoice_is_valid(&active_invoice) == A_ERR_SUCCESS;
    if (!can_save) ImGui::BeginDisabled();
    
    ImGui::Spacing();
    if (ImGui::Button(localize("form.save"))) {
        administration_invoice_update(&active_invoice);
        
        current_view_state = view_state::LIST;

        ui_destroy_invoices();
        ui_setup_invoices();
    } 

    if (!can_save) ImGui::EndDisabled();
}

static void ui_draw_invoice_create()
{
    if (ImGui::Button(localize("form.back"))) {
        current_view_state = view_state::LIST;
    }
    
    draw_invoice_form(&active_invoice);

    bool can_save = administration_invoice_is_valid(&active_invoice) == A_ERR_SUCCESS;
    if (!can_save) ImGui::BeginDisabled();
    
    ImGui::Spacing();
    if (ImGui::Button(localize("form.save"))) {
        administration_invoice_add(&active_invoice);

        current_view_state = view_state::LIST;

        ui_destroy_invoices();
        ui_setup_invoices();
    } 

    if (!can_save) ImGui::EndDisabled();
}

static void ui_draw_invoice_view()
{
    if (ImGui::Button(localize("form.back"))) {
        current_view_state = view_state::LIST;
    }

    draw_invoice_form(&active_invoice, true);
}

void ui_draw_invoices()
{
    switch(current_view_state)
    {
        case view_state::LIST: ui_draw_invoices_list(); break;
        case view_state::CREATE: ui_draw_invoice_create(); break;
        case view_state::EDIT: ui_draw_invoice_update(); break;
        case view_state::VIEW: ui_draw_invoice_view(); break;
    }
}