#include "display_manager.h"
#include "power_manager.h"
#include <M5Unified.h>

// EPD-exact palette: values produce distance=0 in Panel_ED2208's
// _rgb_to_epd_color nearest-color lookup, guaranteeing correct mapping.
// Order matches our pipeline's palette indices (0=black..5=yellow).
static const lgfx::bgr888_t EPD_PALETTE[6] = {
    {0, 0, 0},         // Black  (EPD_BLACK)
    {255, 255, 255},   // White  (EPD_WHITE)
    {191, 0, 0},       // Red    (EPD_RED)
    {67, 138, 28},     // Green  (EPD_GREEN)
    {100, 64, 255},    // Blue   (EPD_BLUE)
    {255, 243, 56}     // Yellow (EPD_YELLOW)
};

void DisplayManager::begin(PowerManager& power) {
    _power = &power;
    _display = &M5.Display;

    // Ensure no automatic e-ink refreshes happen
    _display->setAutoDisplay(false);

    // Set rotation for landscape (device physically rotated)
    _display->setRotation(3);

    // Disable the panel driver's internal dithering (epd_quality applies a diagonal
    // bias pattern via _dither_row_rgb_pair). Since our ImagePipeline already does
    // proper Floyd-Steinberg dithering to the 6-color palette, the driver should
    // just do a clean nearest-color lookup with no additional spatial bias.
    // On Panel_ED2208 this only affects the dither function — NOT refresh quality.
    _display->setEpdMode(epd_mode_t::epd_fastest);

    Serial.printf("[display] Initialized: %dx%d, rotation=%d, epd_mode=fastest (no driver dither)\n",
                  _display->width(), _display->height(), _display->getRotation());
}

void DisplayManager::showSetupScreen() {
    _power->enableEPDPower();

    // Batch all drawing — nothing hits the panel until display() at the end
    _display->startWrite();
    _display->fillScreen(TFT_WHITE);

    // Generate QR code for WiFi auto-connect
    const char* qrData = "WIFI:T:nopass;S:PaperColor-Setup;;";
    QRCode qrcode;
    uint8_t qrcodeData[qrcode_getBufferSize(6)];
    qrcode_initText(&qrcode, qrcodeData, 6, ECC_LOW, qrData);

    // Draw QR code centered vertically, left-of-center horizontally
    int qrSize = qrcode.size;
    int scale = 4;
    int qrPixels = qrSize * scale;
    int qrX = (DISPLAY_WIDTH / 3) - (qrPixels / 2);
    int qrY = (DISPLAY_HEIGHT - qrPixels) / 2;

    for (int y = 0; y < qrSize; y++) {
        for (int x = 0; x < qrSize; x++) {
            uint16_t color = qrcode_getModule(&qrcode, x, y) ? TFT_BLACK : TFT_WHITE;
            _display->fillRect(qrX + x * scale, qrY + y * scale, scale, scale, color);
        }
    }

    // Text instructions to the right of QR code
    int textX = DISPLAY_WIDTH / 2 + 40;
    _display->setTextColor(TFT_BLACK);
    _display->setTextDatum(middle_left);
    _display->setTextSize(2);
    _display->drawString("PaperColor", textX, DISPLAY_HEIGHT / 2 - 60);
    _display->setTextSize(1);
    _display->drawString("Scan QR to connect", textX, DISPLAY_HEIGHT / 2 - 20);
    _display->drawString("or join WiFi:", textX, DISPLAY_HEIGHT / 2 + 10);
    _display->setTextSize(1.5);
    _display->drawString("PaperColor-Setup", textX, DISPLAY_HEIGHT / 2 + 40);
    _display->setTextSize(1);
    _display->drawString("Then open:", textX, DISPLAY_HEIGHT / 2 + 70);
    _display->drawString("192.168.4.1", textX, DISPLAY_HEIGHT / 2 + 95);

    _display->endWrite();

    // Single e-ink refresh — the only panel update during boot
    triggerRefresh();
    _power->disableEPDPower();
}

void DisplayManager::showImage(const ProcessedImage& img) {
    if (!img.valid || img.framebuffer == nullptr) {
        Serial.println("[display] Invalid image — skipping");
        return;
    }

    _power->enableEPDPower();

    Serial.println("[display] Writing framebuffer to e-ink...");

    // Bulk-write framebuffer using palette lookup (handles rotation internally)
    _display->startWrite();
    _display->pushImage(0, 0, img.width, img.height,
        img.framebuffer, lgfx::color_depth_t::palette_8bit, EPD_PALETTE);
    _display->endWrite();
    // Do NOT refresh here — caller should add metadata overlay then call refresh()
}

void DisplayManager::showMessage(const char* title, const char* body) {
    _power->enableEPDPower();

    _display->startWrite();
    _display->fillScreen(TFT_WHITE);
    _display->setTextColor(TFT_BLACK);
    _display->setTextDatum(middle_center);
    _display->setTextSize(2);
    _display->drawString(title, DISPLAY_WIDTH / 2, DISPLAY_HEIGHT / 2 - 30);
    _display->setTextSize(1);
    _display->drawString(body, DISPLAY_WIDTH / 2, DISPLAY_HEIGHT / 2 + 20);
    _display->endWrite();

    triggerRefresh();
    _power->disableEPDPower();
}

void DisplayManager::showMetadata(const AssetInfo& info, uint8_t metaFlags, MetaPosition pos,
                                   const String& dateFmt, const String& timeFmt) {
    showMetadataInRegion(info, metaFlags, pos, 0, 0, DISPLAY_WIDTH, DISPLAY_HEIGHT, dateFmt, timeFmt);
}

void DisplayManager::showMetadataInRegion(const AssetInfo& info, uint8_t metaFlags, MetaPosition pos,
                                           uint16_t regionX, uint16_t regionY,
                                           uint16_t regionW, uint16_t regionH,
                                           const String& dateFmt, const String& timeFmt) {
    if (metaFlags == 0) return;

    // Build metadata string
    String metaText = "";

    // Parse ISO datetime (YYYY-MM-DDTHH:MM:SS) into struct tm for strftime
    if (((metaFlags & META_DATE) || (metaFlags & META_TIME)) && info.dateTime.length() >= 19) {
        struct tm t = {};
        sscanf(info.dateTime.c_str(), "%d-%d-%dT%d:%d:%d",
               &t.tm_year, &t.tm_mon, &t.tm_mday,
               &t.tm_hour, &t.tm_min, &t.tm_sec);
        t.tm_year -= 1900;
        t.tm_mon -= 1;

        char buf[64];
        if ((metaFlags & META_DATE) && (metaFlags & META_TIME)) {
            String combinedFmt = dateFmt + " " + timeFmt;
            strftime(buf, sizeof(buf), combinedFmt.c_str(), &t);
            metaText += buf;
        } else if (metaFlags & META_DATE) {
            strftime(buf, sizeof(buf), dateFmt.c_str(), &t);
            metaText += buf;
        } else {
            strftime(buf, sizeof(buf), timeFmt.c_str(), &t);
            metaText += buf;
        }
    } else if ((metaFlags & META_DATE) && info.dateTime.length() >= 10) {
        // Fallback if datetime is too short for full parse
        metaText += info.dateTime.substring(0, 10);
    }
    if ((metaFlags & META_LOCATION) && info.city.length() > 0) {
        if (metaText.length() > 0) metaText += "  |  ";
        metaText += info.city;
    }
    if ((metaFlags & META_PEOPLE) && !info.people.empty()) {
        if (metaText.length() > 0) metaText += "  |  ";
        for (size_t i = 0; i < info.people.size(); i++) {
            if (i > 0) metaText += ", ";
            metaText += info.people[i];
        }
    }
    if ((metaFlags & META_ALBUM)) {
        // Album name would need to be passed separately
    }
    if ((metaFlags & META_CAMERA) && info.camera.length() > 0) {
        if (metaText.length() > 0) metaText += "  |  ";
        metaText += info.camera;
    }

    if (metaText.length() == 0) return;

    _display->setTextSize(1.5f);
    _display->setTextColor(TFT_WHITE);

    switch (pos) {
        case MetaPosition::CaptionBottom:
        case MetaPosition::CaptionTop: {
            // Bar spanning the region width, positioned at region top or bottom
            uint16_t barH = 36;
            uint16_t barY = (pos == MetaPosition::CaptionTop)
                ? regionY
                : regionY + regionH - barH;
            _display->fillRect(regionX, barY, regionW, barH, TFT_BLACK);
            _display->setTextDatum(middle_center);
            _display->drawString(metaText.c_str(), regionX + regionW / 2, barY + barH / 2);
            break;
        }
        case MetaPosition::OverlayTopLeft:
        case MetaPosition::OverlayTopRight:
        case MetaPosition::OverlayBottomLeft:
        case MetaPosition::OverlayBottomRight: {
            static constexpr uint16_t MARGIN = 8;
            static constexpr uint16_t PAD_X = 8;
            static constexpr uint16_t PAD_Y = 5;
            static constexpr uint16_t TEXT_H = 20;

            uint16_t textW = _display->textWidth(metaText.c_str());
            uint16_t badgeW = min((uint16_t)(textW + PAD_X * 2), regionW);
            uint16_t badgeH = TEXT_H + PAD_Y * 2;

            uint16_t bx, by;
            switch (pos) {
                case MetaPosition::OverlayTopLeft:
                    bx = regionX + MARGIN;
                    by = regionY + MARGIN;
                    break;
                case MetaPosition::OverlayTopRight:
                    bx = regionX + regionW - badgeW - MARGIN;
                    by = regionY + MARGIN;
                    break;
                case MetaPosition::OverlayBottomLeft:
                    bx = regionX + MARGIN;
                    by = regionY + regionH - badgeH - MARGIN;
                    break;
                case MetaPosition::OverlayBottomRight:
                    bx = regionX + regionW - badgeW - MARGIN;
                    by = regionY + regionH - badgeH - MARGIN;
                    break;
                default:
                    bx = regionX + MARGIN;
                    by = regionY + MARGIN;
                    break;
            }

            _display->fillRect(bx, by, badgeW, badgeH, TFT_BLACK);
            _display->setTextDatum(middle_left);
            _display->drawString(metaText.c_str(), bx + PAD_X, by + badgeH / 2);
            break;
        }
    }
}

void DisplayManager::drawBadge(uint16_t x, uint16_t y, uint16_t w, uint16_t h) {
    _display->fillRect(x, y, w, h, TFT_BLACK);
}

void DisplayManager::showSleepIndicator(MetaPosition metaPos) {
    _power->enableEPDPower();

    static constexpr uint16_t MARGIN = 8;
    static constexpr uint16_t PAD_X = 6;
    static constexpr uint16_t PAD_Y = 4;

    _display->setTextSize(1);
    uint16_t textW = _display->textWidth("SLP");
    uint16_t textH = 14;
    uint16_t badgeW = textW + PAD_X * 2;
    uint16_t badgeH = textH + PAD_Y * 2;

    // Pick a corner opposite to metadata position
    uint16_t bx, by;
    switch (metaPos) {
        case MetaPosition::OverlayTopLeft:
        case MetaPosition::CaptionTop:
            bx = DISPLAY_WIDTH - badgeW - MARGIN;
            by = DISPLAY_HEIGHT - badgeH - MARGIN;
            break;
        case MetaPosition::OverlayTopRight:
            bx = MARGIN;
            by = DISPLAY_HEIGHT - badgeH - MARGIN;
            break;
        case MetaPosition::OverlayBottomLeft:
            bx = DISPLAY_WIDTH - badgeW - MARGIN;
            by = MARGIN;
            break;
        case MetaPosition::OverlayBottomRight:
        case MetaPosition::CaptionBottom:
        default:
            bx = MARGIN;
            by = MARGIN;
            break;
    }

    drawBadge(bx, by, badgeW, badgeH);
    _display->setTextColor(TFT_WHITE);
    _display->setTextDatum(middle_center);
    _display->drawString("SLP", bx + badgeW / 2, by + badgeH / 2);
}

void DisplayManager::showBatteryIndicator(uint8_t percent, MetaPosition metaPos) {
    static constexpr uint16_t MARGIN = 8;
    static constexpr uint16_t PAD_X = 6;
    static constexpr uint16_t PAD_Y = 4;

    // Battery icon dimensions
    static constexpr uint16_t BATT_W = 20;
    static constexpr uint16_t BATT_H = 10;
    static constexpr uint16_t NUB_W = 3;
    static constexpr uint16_t NUB_H = 5;
    static constexpr uint16_t GAP = 4;

    // Build percentage text
    char pctText[5];
    snprintf(pctText, sizeof(pctText), "%d%%", percent);

    _display->setTextSize(1);
    uint16_t textW = _display->textWidth(pctText);
    uint16_t textH = 14;

    // Total badge size: icon + gap + text + padding
    uint16_t contentW = BATT_W + NUB_W + GAP + textW;
    uint16_t contentH = max(BATT_H, textH);
    uint16_t badgeW = contentW + PAD_X * 2;
    uint16_t badgeH = contentH + PAD_Y * 2;

    // Position: top-right by default, top-left if metadata occupies top-right
    uint16_t bx, by;
    if (metaPos == MetaPosition::OverlayTopRight) {
        bx = MARGIN;
        by = MARGIN;
    } else {
        bx = DISPLAY_WIDTH - badgeW - MARGIN;
        by = MARGIN;
    }

    // Draw badge background
    drawBadge(bx, by, badgeW, badgeH);

    // Draw battery outline (white rect with 1px border)
    uint16_t iconX = bx + PAD_X;
    uint16_t iconY = by + (badgeH - BATT_H) / 2;
    _display->drawRect(iconX, iconY, BATT_W, BATT_H, TFT_WHITE);

    // Draw nub on right side of battery
    uint16_t nubX = iconX + BATT_W;
    uint16_t nubY = iconY + (BATT_H - NUB_H) / 2;
    _display->fillRect(nubX, nubY, NUB_W, NUB_H, TFT_WHITE);

    // Draw fill level inside battery (1px inset)
    uint16_t fillMaxW = BATT_W - 2;
    uint16_t fillW = (fillMaxW * percent) / 100;
    if (fillW > 0) {
        _display->fillRect(iconX + 1, iconY + 1, fillW, BATT_H - 2, TFT_WHITE);
    }

    // Draw percentage text
    uint16_t textX = iconX + BATT_W + NUB_W + GAP;
    _display->setTextColor(TFT_WHITE);
    _display->setTextDatum(middle_left);
    _display->drawString(pctText, textX, by + badgeH / 2);
}

void DisplayManager::refresh() {
    unsigned long start = millis();
    triggerRefresh();
    unsigned long elapsed = millis() - start;
    Serial.printf("[display] Refresh complete in %lu ms\n", elapsed);
    _power->disableEPDPower();
}

void DisplayManager::triggerRefresh() {
    // Panel_ED2208::_exec_transfer always sends the full 400x600 frame
    // regardless of dirty region — the dirty rect only gates whether
    // a transfer happens at all. ~30ms at 4MHz SPI, fine for photo frame.
    _display->display();
}