#include "invoice.h"

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "pdf.h"
#include "util.h"
#include "wordmark.h"

#define INK "#314c59"
#define WHITE "#ffffff"
#define RULE "#000000"

#define PAGE_LEFT 17.300
#define PAGE_RIGHT_X 577.700
#define BAR_HEADER_Y 53.300
#define BAR_HEADER_H 22.416
#define BAR_TABLE_Y 242.436
#define BAR_TABLE_H 15.410
#define RULE_SUMMARY_Y 507.574
#define RULE_FOOTER_Y 621.756
#define RULE_W 0.7005

#define SIZE_VALUE 9.1065
#define SIZE_LABEL 7.2852
#define SIZE_FOOT 6.3746
#define SIZE_PAGE 9.75

#define ROW_STEP 14.7105
#define DESC_FIRST_STEP 29.4210

#define INFO_VALUE_X 118.8722
#define INFO_LABEL_RIGHT 114.010
#define INFO_BASE_Y 101.1053
#define LABEL_DY 0.3874
#define DRY_LABEL_Y 172.2070
#define DRY_LINE_STEP 10.4716
#define DRY_LINE_Y 174.0293
#define OUR_REF_Y 209.6830
#define YOUR_REF_Y 224.3935

#define ADDR_X 370.3521
#define ADDR_BASE_Y 115.8158

#define TABLE_HEADER_Y 253.8146
#define COL_ARTICLE_X 20.1015
#define COL_DESC_X 118.8722
#define COL_QTY_RIGHT 365.446
#define COL_UNIT_X 370.3521
#define COL_PRICE_RIGHT 433.392
#define COL_NOTE_X 442.4121
#define COL_ANM_RIGHT 504.147
#define COL_AMOUNT_RIGHT 574.892
#define ROW_FIRST_Y 268.5251

#define SUM_LABEL_RIGHT 329.760
#define SUM_VALUE_RIGHT 365.446
#define SUM_R_LABEL 504.170
#define SUM_R_VALUE 574.892
#define SUM_Y_A 518.6040
#define SUM_Y_B 533.3146
#define SUM_Y_C 548.0251
#define SUM_Y_D 569.0401
#define SUM_Y_E 583.7506
#define SUM_Y_OCR 598.4612
#define SUM_Y_TOTAL 615.2373

#define FOOT_LABEL_Y 642.4721
#define FOOT_ORG_Y 641.8922
#define FOOT_NAME_Y 656.6028
#define FOOT_VAT_Y 655.8664
#define FOOT_MOMSY 657.1827
#define FOOT_ADDR_Y 671.3133
#define FOOT_EMAIL_Y 671.3133
#define FOOT_FSKATT_Y 671.8932
#define FOOT_CITY_Y 686.0238
#define FOOT_PAGE_Y 819.7954

#define WORDMARK_X 21.742
#define FAKTURA_X 498.400

static void text_at(struct pdf *p, double x, double base, const char *font,
                    double size, const char *rgb, const char *s)
{
    if (s && *s)
        pdf_text(p, x, base, font, size, rgb, s);
}

static void text_right(struct pdf *p, double right, double base,
                       const char *font, double size, const char *rgb,
                       const char *s)
{
    if (s && *s)
        pdf_text(p, right - pdf_text_width(font, size, s), base, font, size,
                 rgb, s);
}

/* pdf_path consumes SVG-style y-down paths; wordmark.h stores y-up outline
   coordinates, so negate the y of every point before drawing. */
static void draw_wordmark(struct pdf *p, const char *path, double x, double y)
{
    size_t n = strlen(path);
    char *flipped = xmalloc(2 * n + 2);
    char op = 0;
    int num = 0, in_num = 0, y_coord = 0;
    size_t o = 0;

    for (size_t i = 0; i < n; i++) {
        char c = path[i];

        if ((c >= 'A' && c <= 'Z') || (c >= 'a' && c <= 'z')) {
            if (c == 'M' || c == 'L' || c == 'C') {
                op = c;
                num = 0;
            } else if (c == 'Z') {
                op = 0;
            }
            flipped[o++] = c;
            in_num = 0;
            continue;
        }
        if (!in_num && (c == '-' || c == '+' || c == '.' ||
                        (c >= '0' && c <= '9'))) {
            in_num = 1;
            y_coord = op && (num % 2 == 1);
            num++;
            if (y_coord) {
                if (c == '-') {
                    i++;
                    c = path[i];
                } else {
                    flipped[o++] = '-';
                }
            }
        } else if (!(c == '-' || c == '+' || c == '.' ||
                     (c >= '0' && c <= '9'))) {
            in_num = 0;
        }
        flipped[o++] = c;
    }
    flipped[o] = '\0';
    pdf_path(p, flipped, x, y, WHITE);
    free(flipped);
}

static void group_digits(char *out, size_t n, uint64_t v)
{
    char digits[24];
    int len = snprintf(digits, sizeof digits, "%llu",
                       (unsigned long long)v);
    size_t o = 0;

    if (len < 0)
        len = 0;
    for (int i = 0; i < len && o + 1 < n; i++) {
        if (i > 0 && (len - i) % 3 == 0)
            out[o++] = ' ';
        out[o++] = digits[i];
    }
    out[o] = '\0';
}

static uint64_t ore_abs(int64_t v)
{
    return v < 0 ? (uint64_t)(-(v + 1)) + 1 : (uint64_t)v;
}

static void fmt_kronor(int64_t ore, char *out, size_t n, int grouped,
                       int always_cents)
{
    char whole[48];
    uint64_t kr = ore_abs(ore) / 100;
    uint64_t rest = ore_abs(ore) % 100;
    const char *sign = ore < 0 ? "-" : "";

    if (grouped)
        group_digits(whole, sizeof whole, kr);
    else
        snprintf(whole, sizeof whole, "%llu", (unsigned long long)kr);
    if (rest || always_cents)
        snprintf(out, n, "%s%s,%02llu", sign, whole,
                 (unsigned long long)rest);
    else
        snprintf(out, n, "%s%s", sign, whole);
}

static void fmt_quantity(int64_t milli, char *out, size_t n)
{
    uint64_t v = ore_abs(milli);
    uint64_t whole = v / 1000;
    uint64_t frac = v % 1000;
    const char *sign = milli < 0 ? "-" : "";

    if (!frac)
        snprintf(out, n, "%s%llu", sign, (unsigned long long)whole);
    else if (frac % 100 == 0)
        snprintf(out, n, "%s%llu,%llu", sign, (unsigned long long)whole,
                 (unsigned long long)(frac / 100));
    else if (frac % 10 == 0)
        snprintf(out, n, "%s%llu,%02llu", sign, (unsigned long long)whole,
                 (unsigned long long)(frac / 10));
    else
        snprintf(out, n, "%s%llu,%03llu", sign, (unsigned long long)whole,
                 (unsigned long long)frac);
}

static int64_t vat_part(int64_t net, int64_t rate)
{
    int64_t v = net * rate;

    if (v >= 0)
        return (v + 50) / 100;
    return -((-v + 50) / 100);
}

void invoice_totals(const struct invoice_doc *d, struct invoice_totals *t)
{
    if (!t)
        return;
    memset(t, 0, sizeof *t);
    if (!d || (!d->lines && d->nlines))
        return;
    for (size_t i = 0; i < d->nlines; i++) {
        const struct invoice_line *l = &d->lines[i];
        const char *code = l->vat_code ? l->vat_code : "25";

        t->net_ore += l->amount_ore;
        if (strcmp(code, "25") == 0)
            t->net_25 += l->amount_ore;
        else if (strcmp(code, "12") == 0)
            t->net_12 += l->amount_ore;
        else if (strcmp(code, "6") == 0)
            t->net_6 += l->amount_ore;
        else
            t->net_free += l->amount_ore;
    }
    t->vat_ore = vat_part(t->net_25, 25) + vat_part(t->net_12, 12) +
                 vat_part(t->net_6, 6);
    t->total_ore = t->net_ore + t->vat_ore;
}

int invoice_ocr_check(const char *number_digits)
{
    size_t len;
    int sum = 0;

    if (!number_digits)
        return -1;
    len = strlen(number_digits);
    if (!len)
        return 0;
    for (size_t i = 0; i < len; i++)
        if (number_digits[i] < '0' || number_digits[i] > '9')
            return -1;
    for (size_t i = 0; i < len; i++) {
        int d = number_digits[len - 1 - i] - '0';

        if (i % 2 == 0) {
            d *= 2;
            if (d > 9)
                d -= 9;
        }
        sum += d;
    }
    return (10 - sum % 10) % 10;
}

static size_t count_lines(const char *s)
{
    size_t n = 1;

    if (!s)
        return n;
    for (const char *p = s; *p; p++)
        if (*p == '\n')
            n++;
    return n;
}

static double desc_offset(size_t line)
{
    if (line == 0)
        return 0.0;
    if (line == 1)
        return DESC_FIRST_STEP;
    return DESC_FIRST_STEP + (double)(line - 1) * ROW_STEP;
}

static void put_desc_line(struct pdf *p, double y, const char *s, size_t len)
{
    char buf[512];

    if (!len)
        return;
    snprintf(buf, sizeof buf, "%.*s", (int)len, s);
    pdf_text(p, COL_DESC_X, y, "H", SIZE_VALUE, INK, buf);
}

static void put_address(struct pdf *p, double x, double y, const char *rgb,
                        double size, const char *postal, const char *city)
{
    char buf[128];

    if (!postal)
        postal = "";
    if (!city)
        city = "";
    if (*postal && *city)
        snprintf(buf, sizeof buf, "%s %s", postal, city);
    else
        snprintf(buf, sizeof buf, "%s%s", postal, city);
    if (*buf)
        pdf_text(p, x, y, "H", size, rgb, buf);
}

static int doc_fits(const struct invoice_doc *d)
{
    double y = ROW_FIRST_Y;

    for (size_t i = 0; i < d->nlines; i++) {
        const char *s = d->lines[i].description;
        size_t n = count_lines(s);

        if (!s)
            s = "";
        for (size_t k = 0; k < n; k++) {
            if (y + desc_offset(k) > RULE_SUMMARY_Y - 4.0)
                return 0;
            s = strchr(s, '\n');
            if (s)
                s++;
        }
        y += (double)(n + 1) * ROW_STEP;
    }
    return 1;
}

static void draw_info(struct pdf *p, const struct invoice_doc *d)
{
    static const char *const labels[5] = {
        "Fakturanummer", "Fakturadatum", "Leveransdatum", "Ert momsreg.nr",
        "Betalningsvilkor",
    };
    char number[32], payment[32];
    const char *values[5];

    snprintf(number, sizeof number, "%lld", (long long)d->number);
    snprintf(payment, sizeof payment, "%d dagar", d->payment_days);
    values[0] = number;
    values[1] = d->invoice_date;
    values[2] = d->delivery_date;
    values[3] = d->customer.vat_nr;
    values[4] = payment;

    for (size_t i = 0; i < 5; i++) {
        double y = INFO_BASE_Y + (double)i * ROW_STEP;

        text_right(p, INFO_LABEL_RIGHT, y + LABEL_DY, "HB", SIZE_LABEL, INK,
                   labels[i]);
        text_at(p, INFO_VALUE_X, y, "H", SIZE_VALUE, INK, values[i]);
    }
    text_right(p, INFO_LABEL_RIGHT, DRY_LABEL_Y, "HB", SIZE_LABEL, INK,
               "Dröjsmålsränta");
    text_at(p, INFO_VALUE_X, DRY_LINE_Y, "H", SIZE_VALUE, INK,
            "Vid betalning efter");
    text_at(p, INFO_VALUE_X, DRY_LINE_Y + DRY_LINE_STEP, "H", SIZE_VALUE, INK,
            "förfallodagen debiteras");
    text_at(p, INFO_VALUE_X, DRY_LINE_Y + 2 * DRY_LINE_STEP, "H", SIZE_VALUE,
            INK, "ränta enligt räntelagen");
    text_right(p, INFO_LABEL_RIGHT, OUR_REF_Y + LABEL_DY, "HB", SIZE_LABEL,
               INK, "Vår referens");
    text_at(p, INFO_VALUE_X, OUR_REF_Y, "H", SIZE_VALUE, INK, d->our_ref);
    text_right(p, INFO_LABEL_RIGHT, YOUR_REF_Y + LABEL_DY, "HB", SIZE_LABEL,
               INK, "Er referens");
    text_at(p, INFO_VALUE_X, YOUR_REF_Y, "H", SIZE_VALUE, INK, d->your_ref);
}

static void draw_customer(struct pdf *p, const struct invoice_customer *c)
{
    const char *s = c->address ? c->address : "";
    double y = ADDR_BASE_Y;

    text_at(p, ADDR_X, INFO_BASE_Y, "HB", SIZE_VALUE, INK, "Fakturaadress");
    text_at(p, ADDR_X, y, "H", SIZE_VALUE, INK, c->name);
    y += ROW_STEP;
    for (;;) {
        const char *nl = strchr(s, '\n');

        if (nl) {
            char buf[512];

            snprintf(buf, sizeof buf, "%.*s", (int)(nl - s), s);
            if (*buf)
                pdf_text(p, ADDR_X, y, "H", SIZE_VALUE, INK, buf);
            y += ROW_STEP;
            s = nl + 1;
        } else {
            if (*s)
                pdf_text(p, ADDR_X, y, "H", SIZE_VALUE, INK, s);
            break;
        }
    }
    put_address(p, ADDR_X, y + ROW_STEP, INK, SIZE_VALUE, c->postal_code,
                c->city);
}

static void draw_table(struct pdf *p, const struct invoice_doc *d)
{
    double y = ROW_FIRST_Y;

    pdf_fill_rect(p, PAGE_LEFT, BAR_TABLE_Y, PAGE_RIGHT_X - PAGE_LEFT,
                  BAR_TABLE_H, INK);
    text_at(p, COL_ARTICLE_X, TABLE_HEADER_Y, "HB", SIZE_VALUE, WHITE,
            "Art.nr");
    text_at(p, COL_DESC_X, TABLE_HEADER_Y, "HB", SIZE_VALUE, WHITE,
            "Beskrivning");
    text_right(p, COL_QTY_RIGHT, TABLE_HEADER_Y, "HB", SIZE_VALUE, WHITE,
               "Antal");
    text_right(p, COL_PRICE_RIGHT, TABLE_HEADER_Y, "HB", SIZE_VALUE, WHITE,
               "á-pris");
    text_right(p, COL_ANM_RIGHT, TABLE_HEADER_Y, "HB", SIZE_VALUE, WHITE,
               "Anm");
    text_right(p, COL_AMOUNT_RIGHT, TABLE_HEADER_Y, "HB", SIZE_VALUE, WHITE,
               "Belopp");

    for (size_t i = 0; i < d->nlines; i++) {
        const struct invoice_line *l = &d->lines[i];
        char qty[32], price[48], amount[48];
        const char *s = l->description ? l->description : "";
        size_t line = 0;

        fmt_quantity(l->quantity_milli, qty, sizeof qty);
        fmt_kronor(l->unit_price_ore, price, sizeof price, 0, 0);
        fmt_kronor(l->amount_ore, amount, sizeof amount, 0, 0);

        for (;;) {
            const char *nl = strchr(s, '\n');

            if (nl) {
                put_desc_line(p, y + desc_offset(line), s, (size_t)(nl - s));
                s = nl + 1;
                line++;
            } else {
                put_desc_line(p, y + desc_offset(line), s, strlen(s));
                break;
            }
        }
        text_at(p, COL_ARTICLE_X, y, "H", SIZE_VALUE, INK, l->article_no);
        text_right(p, COL_QTY_RIGHT, y, "H", SIZE_VALUE, INK, qty);
        text_at(p, COL_UNIT_X, y, "H", SIZE_VALUE, INK, l->unit);
        text_right(p, COL_PRICE_RIGHT, y, "H", SIZE_VALUE, INK, price);
        text_at(p, COL_NOTE_X, y, "H", SIZE_VALUE, INK, l->note);
        text_right(p, COL_AMOUNT_RIGHT, y, "H", SIZE_VALUE, INK, amount);

        y += (double)(line + 2) * ROW_STEP;
    }
}

static void draw_summary(struct pdf *p, const struct invoice_doc *d,
                         const struct invoice_totals *t)
{
    char value[64], total[64];

    pdf_line(p, PAGE_LEFT, RULE_SUMMARY_Y, PAGE_RIGHT_X, RULE_SUMMARY_Y,
             RULE_W, RULE);

    text_right(p, SUM_LABEL_RIGHT, SUM_Y_A + LABEL_DY, "H", SIZE_LABEL, INK,
               "Momsunderlag");
    text_right(p, SUM_R_LABEL, SUM_Y_A + LABEL_DY, "H", SIZE_LABEL, INK,
               "Belopp före moms");
    fmt_kronor(t->net_ore, value, sizeof value, 0, 0);
    text_right(p, SUM_R_VALUE, SUM_Y_A, "H", SIZE_VALUE, INK, value);

    text_right(p, SUM_LABEL_RIGHT, SUM_Y_B + LABEL_DY, "H", SIZE_LABEL, INK,
               "Moms 25%");
    fmt_kronor(t->net_25, value, sizeof value, 0, 0);
    text_right(p, SUM_VALUE_RIGHT, SUM_Y_B, "H", SIZE_VALUE, INK, value);
    text_right(p, SUM_R_LABEL, SUM_Y_B + LABEL_DY, "H", SIZE_LABEL, INK,
               "Total moms");
    fmt_kronor(t->vat_ore, value, sizeof value, 0, 0);
    text_right(p, SUM_R_VALUE, SUM_Y_B, "H", SIZE_VALUE, INK, value);

    text_right(p, SUM_LABEL_RIGHT, SUM_Y_C + LABEL_DY, "H", SIZE_LABEL, INK,
               "Moms 12%");
    fmt_kronor(t->net_12, value, sizeof value, 0, 0);
    text_right(p, SUM_VALUE_RIGHT, SUM_Y_C, "H", SIZE_VALUE, INK, value);
    text_right(p, SUM_R_LABEL, SUM_Y_C + LABEL_DY, "H", SIZE_LABEL, INK,
               "Öresutjämning");

    text_right(p, SUM_LABEL_RIGHT, SUM_Y_D + LABEL_DY, "H", SIZE_LABEL, INK,
               "Moms 6%");
    fmt_kronor(t->net_6, value, sizeof value, 0, 0);
    text_right(p, SUM_VALUE_RIGHT, SUM_Y_D, "H", SIZE_VALUE, INK, value);
    text_right(p, SUM_R_LABEL, SUM_Y_D + LABEL_DY, "H", SIZE_LABEL, INK,
               "Förfallodatum");
    text_right(p, SUM_R_VALUE, SUM_Y_D, "H", SIZE_VALUE, INK, d->due_date);

    text_right(p, SUM_LABEL_RIGHT, SUM_Y_E + LABEL_DY, "H", SIZE_LABEL, INK,
               "Momsfritt");
    fmt_kronor(t->net_free, value, sizeof value, 0, 0);
    text_right(p, SUM_VALUE_RIGHT, SUM_Y_E, "H", SIZE_VALUE, INK, value);
    text_right(p, SUM_R_LABEL, SUM_Y_E + LABEL_DY, "H", SIZE_LABEL, INK,
               "Bankgiro");
    text_right(p, SUM_R_VALUE, SUM_Y_E, "H", SIZE_VALUE, INK,
               d->seller.bankgiro);

    text_right(p, SUM_R_LABEL, SUM_Y_OCR, "H", SIZE_VALUE, INK, "OCR");
    text_right(p, SUM_R_VALUE, SUM_Y_OCR, "H", SIZE_VALUE, INK, d->ocr);

    text_right(p, SUM_R_LABEL, SUM_Y_TOTAL, "HB", SIZE_VALUE, INK,
               "Summa att betala SEK");
    fmt_kronor(t->total_ore, total, sizeof total, 1, 1);
    text_right(p, SUM_R_VALUE, SUM_Y_TOTAL, "HB", SIZE_VALUE, INK, total);
}

static void draw_footer(struct pdf *p, const struct invoice_doc *d)
{
    const struct invoice_seller *s = &d->seller;

    pdf_line(p, PAGE_LEFT, RULE_FOOTER_Y, PAGE_RIGHT_X, RULE_FOOTER_Y, RULE_W,
             RULE);
    text_at(p, COL_ARTICLE_X, FOOT_LABEL_Y, "HB", SIZE_FOOT, INK, "Adress");
    text_at(p, INFO_VALUE_X, FOOT_LABEL_Y, "HB", SIZE_FOOT, INK, "Kontakt");
    text_at(p, 263.8759, FOOT_LABEL_Y, "HB", SIZE_FOOT, INK, "Orgnr");
    text_at(p, COL_ARTICLE_X, FOOT_NAME_Y, "H", SIZE_VALUE, INK, s->name);
    if (s->phone && *s->phone) {
        char phone[64];

        snprintf(phone, sizeof phone, " %s", s->phone);
        pdf_text(p, INFO_VALUE_X, FOOT_NAME_Y, "H", SIZE_VALUE, INK, phone);
    }
    text_at(p, COL_ARTICLE_X, FOOT_ADDR_Y, "H", SIZE_VALUE, INK, s->address);
    text_at(p, INFO_VALUE_X, FOOT_EMAIL_Y, "H", SIZE_VALUE, INK, s->email);
    put_address(p, COL_ARTICLE_X, FOOT_CITY_Y, INK, SIZE_VALUE, s->postal_code,
                s->city);
    text_at(p, 334.6266, FOOT_ORG_Y, "H", SIZE_VALUE, INK, s->org_nr);
    text_at(p, 263.8759, FOOT_MOMSY, "HB", SIZE_FOOT, INK, "Momsregnr");
    text_at(p, 334.6266, FOOT_VAT_Y, "H", SIZE_VALUE, INK, s->vat_nr);
    text_at(p, 263.8759, FOOT_FSKATT_Y, "HB", SIZE_FOOT, INK,
            "Godkänd för F-skatt");
    text_at(p, 567.4275, FOOT_PAGE_Y, "H", SIZE_PAGE, INK, "1");
}

int invoice_render_pdf(const struct invoice_doc *d, unsigned char **out,
                       size_t *len)
{
    struct invoice_totals t;
    struct pdf *p;

    if (out)
        *out = NULL;
    if (len)
        *len = 0;
    if (!d || !out || !len)
        return -1;
    if (d->nlines && !d->lines)
        return -1;
    if (!doc_fits(d))
        return -1;

    invoice_totals(d, &t);
    p = pdf_new();
    pdf_page(p);
    pdf_fill_rect(p, PAGE_LEFT, BAR_HEADER_Y, PAGE_RIGHT_X - PAGE_LEFT,
                  BAR_HEADER_H, INK);
    draw_wordmark(p, WORDMARK_MAKANDRA, WORDMARK_X, 69.1358);
    draw_wordmark(p, WORDMARK_FAKTURA, FAKTURA_X, 69.1358);
    draw_info(p, d);
    draw_customer(p, &d->customer);
    draw_table(p, d);
    draw_summary(p, d, &t);
    draw_footer(p, d);
    *out = pdf_finish(p, len);
    return *out ? 0 : -1;
}