/*
    * main.cpp
    * Wikipedia client for MontaukOS (TLS 1.2 via BearSSL)
    * Interactive fullscreen pager with colored output
    * Usage: wiki <title>          Show article summary
    *        wiki -f <title>       Show full article
    *        wiki -s <query>       Search for articles
    * Copyright (c) 2025-2026 Daniel Hammer
*/

#include <montauk/syscall.h>
#include <montauk/string.h>
#include <tls/tls.hpp>

extern "C" {
#include <string.h>
#include <stdlib.h>
#include <stdio.h>
}

using montauk::skip_spaces;

static constexpr int RESP_MAX = 131072;  // 128 KB
static const char WIKI_HOST[] = "en.wikipedia.org";
static constexpr int MAX_LINES = 4096;
static constexpr int MAX_SEARCH_RESULTS = 10;

enum Mode { MODE_SUMMARY, MODE_FULL, MODE_SEARCH, MODE_DUMP };
enum LineType { LINE_BLANK, LINE_TITLE, LINE_DESC, LINE_SECTION, LINE_BODY };

struct WikiLine {
    const char* text;
    int len;
    LineType type;
    int level;
};

// ---- Global state (loaded once, reused across fetches) ----

static uint32_t g_serverIp = 0;
static tls::TrustAnchors g_tas = {nullptr, 0, 0};

// ---- Screen buffer for flicker-free rendering ----

static constexpr int SB_SIZE = 32768;
static char g_sb[SB_SIZE];
static int g_sbPos = 0;

static void sb_reset() { g_sbPos = 0; }
static void sb_putc(char c) { if (g_sbPos < SB_SIZE - 1) g_sb[g_sbPos++] = c; }
static void sb_puts(const char* s) { while (*s && g_sbPos < SB_SIZE - 1) g_sb[g_sbPos++] = *s++; }
static void sb_flush() { g_sb[g_sbPos] = '\0'; montauk::print(g_sb); }

static int int_to_buf(char* buf, int n) {
    if (n <= 0) { buf[0] = '0'; return 1; }
    char tmp[12]; int i = 0;
    while (n > 0) { tmp[i++] = '0' + (n % 10); n /= 10; }
    for (int j = 0; j < i; j++) buf[j] = tmp[i - 1 - j];
    return i;
}

static void sb_cursor_to(int row, int col) {
    sb_puts("\033[");
    char tmp[12]; int n = int_to_buf(tmp, row);
    for (int i = 0; i < n; i++) sb_putc(tmp[i]);
    sb_putc(';');
    n = int_to_buf(tmp, col);
    for (int i = 0; i < n; i++) sb_putc(tmp[i]);
    sb_putc('H');
}

// ---- Keyboard abort check for TLS ----

static bool check_keyboard_abort() {
    if (montauk::is_key_available()) {
        montauk::abi::KeyEvent ev;
        montauk::getkey(&ev);
        if (ev.pressed && ev.ctrl && ev.ascii == 'q') return true;
    }
    return false;
}

// ---- HTTPS fetch wrapper ----

static int wiki_fetch(const char* path, char* respBuf, int respMax) {
    static char request[2560];  // keep off stack
    int reqLen = snprintf(request, sizeof(request),
        "GET %s HTTP/1.0\r\n"
        "Host: %s\r\n"
        "User-Agent: MontaukOS/1.0 wiki\r\n"
        "Accept: application/json\r\n"
        "Connection: close\r\n"
        "\r\n",
        path, WIKI_HOST);
    return tls::https_fetch(WIKI_HOST, g_serverIp, 443,
                            request, reqLen, g_tas,
                            respBuf, respMax, check_keyboard_abort);
}

// ---- HTTP response parsing ----

static int find_header_end(const char* buf, int len) {
    for (int i = 0; i + 3 < len; i++) {
        if (buf[i] == '\r' && buf[i+1] == '\n' && buf[i+2] == '\r' && buf[i+3] == '\n')
            return i + 4;
    }
    return -1;
}

static int parse_status_code(const char* buf, int len) {
    int i = 0;
    while (i < len && buf[i] != ' ') i++;
    if (i >= len) return -1;
    i++;
    if (i + 2 >= len) return -1;
    if (buf[i] < '0' || buf[i] > '9') return -1;
    return (buf[i] - '0') * 100 + (buf[i+1] - '0') * 10 + (buf[i+2] - '0');
}

// ---- URL encoding ----

static int url_encode_title(const char* in, char* out, int maxLen) {
    const char hex[] = "0123456789ABCDEF";
    int j = 0;
    for (int i = 0; in[i] && j < maxLen - 4; i++) {
        char c = in[i];
        if (c == ' ') {
            out[j++] = '_';
        } else if ((c >= 'A' && c <= 'Z') || (c >= 'a' && c <= 'z') ||
                   (c >= '0' && c <= '9') || c == '-' || c == '_' ||
                   c == '.' || c == '~' || c == '(' || c == ')' || c == ',') {
            out[j++] = c;
        } else {
            out[j++] = '%';
            out[j++] = hex[(unsigned char)c >> 4];
            out[j++] = hex[(unsigned char)c & 0x0F];
        }
    }
    out[j] = '\0';
    return j;
}

static int url_encode_query(const char* in, char* out, int maxLen) {
    const char hex[] = "0123456789ABCDEF";
    int j = 0;
    for (int i = 0; in[i] && j < maxLen - 4; i++) {
        char c = in[i];
        if (c == ' ') {
            out[j++] = '+';
        } else if ((c >= 'A' && c <= 'Z') || (c >= 'a' && c <= 'z') ||
                   (c >= '0' && c <= '9') || c == '-' || c == '_' ||
                   c == '.' || c == '~') {
            out[j++] = c;
        } else {
            out[j++] = '%';
            out[j++] = hex[(unsigned char)c >> 4];
            out[j++] = hex[(unsigned char)c & 0x0F];
        }
    }
    out[j] = '\0';
    return j;
}

// ---- JSON string extraction ----

static int extract_json_string(const char* buf, int len, const char* key,
                                char* out, int maxOut) {
    int klen = (int)strlen(key);

    for (int i = 0; i < len - klen - 3; i++) {
        if (buf[i] != '"') continue;
        if (memcmp(buf + i + 1, key, klen) != 0) continue;
        if (buf[i + 1 + klen] != '"') continue;
        if (buf[i + 2 + klen] != ':') continue;

        int p = i + 3 + klen;
        while (p < len && (buf[p] == ' ' || buf[p] == '\t')) p++;
        if (p >= len || buf[p] != '"') continue;
        p++;

        int j = 0;
        while (p < len && j < maxOut - 4) {
            if (buf[p] == '"') break;
            if (buf[p] == '\\' && p + 1 < len) {
                p++;
                switch (buf[p]) {
                case '"':  out[j++] = '"'; break;
                case '\\': out[j++] = '\\'; break;
                case 'n':  out[j++] = '\n'; break;
                case 'r':  break;
                case 't':  out[j++] = '\t'; break;
                case '/':  out[j++] = '/'; break;
                case 'u': {
                    if (p + 4 < len) {
                        unsigned val = 0;
                        for (int k = 1; k <= 4; k++) {
                            char h = buf[p + k];
                            val <<= 4;
                            if (h >= '0' && h <= '9') val |= h - '0';
                            else if (h >= 'a' && h <= 'f') val |= h - 'a' + 10;
                            else if (h >= 'A' && h <= 'F') val |= h - 'A' + 10;
                        }
                        p += 4;
                        if (val < 128) out[j++] = (char)val;
                        else if (val == 0x2013 || val == 0x2014) out[j++] = '-';
                        else if (val == 0x2018 || val == 0x2019) out[j++] = '\'';
                        else if (val == 0x201C || val == 0x201D) out[j++] = '"';
                        else if (val == 0x2026) { out[j++] = '.'; out[j++] = '.'; out[j++] = '.'; }
                        else out[j++] = '?';
                    }
                    break;
                }
                default: out[j++] = buf[p]; break;
                }
            } else {
                out[j++] = buf[p];
            }
            p++;
        }
        out[j] = '\0';
        return j;
    }

    out[0] = '\0';
    return 0;
}

// ---- Display line building (word wrap + section detection) ----

// Word-wrap a single paragraph into the lines array. Returns lines added.
static int wrap_paragraph(const char* text, int textLen, int cols,
                          WikiLine* lines, int maxLines, LineType type) {
    if (maxLines <= 0 || textLen <= 0 || cols <= 0) return 0;
    int count = 0;
    const char* p = text;
    const char* end = text + textLen;

    while (p < end && count < maxLines) {
        while (p < end && *p == ' ') p++;
        if (p >= end) break;

        const char* lineStart = p;
        const char* lastSpace = nullptr;
        int col = 0;

        while (p < end && col < cols) {
            if (*p == ' ') lastSpace = p;
            p++;
            col++;
        }

        if (p >= end) {
            // Rest fits on one line
            lines[count].text = lineStart;
            lines[count].len = (int)(p - lineStart);
            lines[count].type = type;
            lines[count].level = 0;
            count++;
        } else if (lastSpace && lastSpace > lineStart) {
            // Wrap at last space
            lines[count].text = lineStart;
            lines[count].len = (int)(lastSpace - lineStart);
            lines[count].type = type;
            lines[count].level = 0;
            count++;
            p = lastSpace + 1;
        } else {
            // Force break (word longer than cols)
            lines[count].text = lineStart;
            lines[count].len = (int)(p - lineStart);
            lines[count].type = type;
            lines[count].level = 0;
            count++;
        }
    }
    return count;
}

// Build all display lines from article parts. Returns total line count.
static int build_lines(WikiLine* lines, int maxLines,
                       const char* title, const char* description,
                       const char* extract, int extractLen,
                       int cols, bool fullMode) {
    int n = 0;

    // Title
    if (title && title[0] && n < maxLines) {
        n += wrap_paragraph(title, (int)strlen(title), cols,
                            lines + n, maxLines - n, LINE_TITLE);
    }

    // Description
    if (description && description[0] && n < maxLines) {
        n += wrap_paragraph(description, (int)strlen(description), cols,
                            lines + n, maxLines - n, LINE_DESC);
    }

    // Blank separator
    if (n > 0 && n < maxLines) {
        lines[n].text = "";
        lines[n].len = 0;
        lines[n].type = LINE_BLANK;
        lines[n].level = 0;
        n++;
    }

    // Process extract line by line
    const char* p = extract;
    const char* end = extract + extractLen;

    while (p < end && n < maxLines) {
        const char* lineStart = p;
        while (p < end && *p != '\n') p++;
        int lineLen = (int)(p - lineStart);
        if (p < end) p++; // skip \n

        // Blank line
        if (lineLen == 0) {
            lines[n].text = "";
            lines[n].len = 0;
            lines[n].type = LINE_BLANK;
            lines[n].level = 0;
            n++;
            continue;
        }

        // Section header detection (== Title ==)
        if (fullMode && lineLen >= 4 && lineStart[0] == '=' && lineStart[1] == '=') {
            int level = 0;
            int si = 0;
            while (si < lineLen && lineStart[si] == '=') { level++; si++; }
            while (si < lineLen && lineStart[si] == ' ') si++;
            int ei = lineLen;
            while (ei > si && lineStart[ei - 1] == '=') ei--;
            while (ei > si && lineStart[ei - 1] == ' ') ei--;

            // Blank line before section for spacing
            if (n > 0 && n < maxLines) {
                lines[n].text = "";
                lines[n].len = 0;
                lines[n].type = LINE_BLANK;
                lines[n].level = 0;
                n++;
            }

            if (n < maxLines) {
                lines[n].text = lineStart + si;
                lines[n].len = ei - si;
                lines[n].type = LINE_SECTION;
                lines[n].level = level;
                n++;
            }
            continue;
        }

        // Regular text — word wrap
        n += wrap_paragraph(lineStart, lineLen, cols,
                            lines + n, maxLines - n, LINE_BODY);
    }

    return n;
}

// ---- Pager rendering ----

static void render_pager(WikiLine* lines, int totalLines, int scroll,
                         int rows, int cols, const char* statusTitle,
                         const char* modeLabel) {
    int contentRows = rows - 1;
    sb_reset();
    sb_puts("\033[?25l");

    for (int r = 0; r < contentRows; r++) {
        sb_cursor_to(r + 1, 1);
        sb_puts("\033[2K");

        int idx = scroll + r;
        if (idx < 0 || idx >= totalLines) continue;

        WikiLine& ln = lines[idx];
        if (ln.type == LINE_BLANK) continue;

        switch (ln.type) {
        case LINE_TITLE:
            sb_puts("\033[1;36m"); // bold cyan
            break;
        case LINE_DESC:
            sb_puts("\033[33m");   // yellow
            break;
        case LINE_SECTION: {
            int indent = (ln.level <= 2) ? 0 : (ln.level - 2) * 2;
            for (int i = 0; i < indent; i++) sb_putc(' ');
            sb_puts("\033[1;32m"); // bold green
            break;
        }
        default:
            break;
        }

        int maxW = cols;
        if (ln.type == LINE_SECTION && ln.level > 2)
            maxW -= (ln.level - 2) * 2;
        int printLen = ln.len;
        if (printLen > maxW) printLen = maxW;
        for (int c = 0; c < printLen; c++)
            sb_putc(ln.text[c]);

        if (ln.type != LINE_BODY)
            sb_puts("\033[0m");
    }

    // Status bar
    sb_cursor_to(rows, 1);
    sb_puts("\033[7m");

    int visCol = 0;
    // Helper: write string and track visible columns
    #define SB_STATUS(s) do { const char* _s = (s); while (*_s) { sb_putc(*_s++); visCol++; } } while(0)

    SB_STATUS(" Wikipedia ");
    sb_puts("\033[7;33m"); // yellow reverse
    SB_STATUS(modeLabel);
    sb_puts("\033[7;37m"); // white reverse
    SB_STATUS(" | ");

    // Truncated title
    int maxTitleLen = cols / 3;
    int titleLen = (int)strlen(statusTitle);
    if (titleLen > maxTitleLen && maxTitleLen > 3) {
        for (int i = 0; i < maxTitleLen - 3; i++) { sb_putc(statusTitle[i]); visCol++; }
        SB_STATUS("...");
    } else {
        SB_STATUS(statusTitle);
    }

    SB_STATUS(" | ");
    char numStr[32];
    int nLen = snprintf(numStr, sizeof(numStr), "%d/%d", scroll + 1, totalLines);
    for (int i = 0; i < nLen; i++) { sb_putc(numStr[i]); visCol++; }
    SB_STATUS(" | q:Quit j/k:Scroll Space/b:Page ");

    #undef SB_STATUS

    // Pad to fill row
    while (visCol < cols) { sb_putc(' '); visCol++; }
    sb_puts("\033[0m");

    sb_flush();
}

static void run_pager(WikiLine* lines, int totalLines, const char* title,
                      const char* modeLabel, bool useAltScreen) {
    int cols = 80, rows = 25;
    montauk::termsize(&cols, &rows);

    if (useAltScreen) {
        montauk::print("\033[?1049h");
        montauk::print("\033[?25l");
    }

    int scroll = 0;
    int maxScroll = totalLines - (rows - 1);
    if (maxScroll < 0) maxScroll = 0;

    render_pager(lines, totalLines, scroll, rows, cols, title, modeLabel);

    bool running = true;
    while (running) {
        while (!montauk::is_key_available()) montauk::yield();

        montauk::abi::KeyEvent ev;
        montauk::getkey(&ev);
        if (!ev.pressed) continue;

        int contentRows = rows - 1;

        if (ev.ascii == 'q' || (ev.ctrl && ev.ascii == 'q')) {
            running = false;
            break;
        }

        switch (ev.ascii) {
        case 'j': if (scroll < maxScroll) scroll++; break;
        case 'k': if (scroll > 0) scroll--; break;
        case ' ': scroll += contentRows; if (scroll > maxScroll) scroll = maxScroll; break;
        case 'b': scroll -= contentRows; if (scroll < 0) scroll = 0; break;
        case 'g': scroll = 0; break;
        case 'G': scroll = maxScroll; break;
        default:
            switch (ev.scancode) {
            case 0x48: if (scroll > 0) scroll--; break;           // Up
            case 0x50: if (scroll < maxScroll) scroll++; break;   // Down
            case 0x49: scroll -= contentRows; if (scroll < 0) scroll = 0; break; // PgUp
            case 0x51: scroll += contentRows; if (scroll > maxScroll) scroll = maxScroll; break; // PgDn
            case 0x47: scroll = 0; break;         // Home
            case 0x4F: scroll = maxScroll; break;  // End
            }
            break;
        }

        if (running)
            render_pager(lines, totalLines, scroll, rows, cols, title, modeLabel);
    }

    if (useAltScreen) {
        montauk::print("\033[?25h");
        montauk::print("\033[?1049l");
    }
}

// ---- Search results ----

static int parse_search_titles(const char* body, int bodyLen,
                               char titles[][256], int maxResults) {
    int brackets = 0;
    int start = -1;
    for (int i = 0; i < bodyLen; i++) {
        if (body[i] == '[') {
            brackets++;
            if (brackets == 2) { start = i + 1; break; }
        }
    }
    if (start < 0) return 0;

    int count = 0;
    int i = start;
    while (i < bodyLen && body[i] != ']' && count < maxResults) {
        while (i < bodyLen && (body[i] == ' ' || body[i] == ',' ||
               body[i] == '\n' || body[i] == '\r')) i++;
        if (i >= bodyLen || body[i] == ']') break;

        if (body[i] == '"') {
            i++;
            int j = 0;
            while (i < bodyLen && body[i] != '"' && j < 255) {
                if (body[i] == '\\' && i + 1 < bodyLen) {
                    i++;
                    titles[count][j++] = body[i];
                } else {
                    titles[count][j++] = body[i];
                }
                i++;
            }
            titles[count][j] = '\0';
            if (i < bodyLen) i++;
            count++;
        } else {
            i++;
        }
    }
    return count;
}

static void render_search(char titles[][256], int count, const char* query,
                          int rows, int cols) {
    sb_reset();
    sb_puts("\033[?25l");
    sb_puts("\033[2J"); // clear screen

    // Header
    sb_cursor_to(2, 3);
    sb_puts("\033[1;36mWikipedia\033[0m");
    sb_puts("\033[90m - The Free Encyclopedia\033[0m");

    // Search query
    sb_cursor_to(4, 3);
    sb_puts("\033[1mSearch results for \"\033[33m");
    sb_puts(query);
    sb_puts("\033[0;1m\":\033[0m");

    // Results
    int resultRow = 6;
    for (int i = 0; i < count; i++) {
        sb_cursor_to(resultRow + i, 3);
        sb_puts("\033[1;36m");
        char num[8];
        snprintf(num, sizeof(num), "%2d", i + 1);
        sb_puts(num);
        sb_puts("\033[0m  \033[1;37m");
        // Truncate long titles
        int tLen = (int)strlen(titles[i]);
        int maxT = cols - 10;
        if (tLen > maxT && maxT > 3) {
            for (int c = 0; c < maxT - 3; c++) sb_putc(titles[i][c]);
            sb_puts("...");
        } else {
            sb_puts(titles[i]);
        }
        sb_puts("\033[0m");
    }

    if (count == 0) {
        sb_cursor_to(resultRow, 3);
        sb_puts("\033[33m(no results found)\033[0m");
    }

    // Instructions
    sb_cursor_to(resultRow + count + 2, 3);
    sb_puts("\033[90mPress ");
    if (count > 0) {
        sb_puts("\033[0;1m1");
        if (count > 1) {
            sb_putc('-');
            if (count >= 10) sb_putc('0');
            else sb_putc('0' + count);
        }
        sb_puts("\033[0;90m to view article, ");
    }
    sb_puts("\033[0;1mq\033[0;90m to quit\033[0m");

    // Status bar
    sb_cursor_to(rows, 1);
    sb_puts("\033[7m");
    char statusStr[256];
    snprintf(statusStr, sizeof(statusStr),
        " Wikipedia Search | \"%s\" | %d result%s ",
        query, count, count == 1 ? "" : "s");
    sb_puts(statusStr);
    int sLen = (int)strlen(statusStr);
    for (int i = sLen; i < cols; i++) sb_putc(' ');
    sb_puts("\033[0m");

    sb_flush();
}

// Returns selected index (0-based), or -1 for quit
static int run_search(char titles[][256], int count, const char* query,
                      int rows, int cols) {
    render_search(titles, count, query, rows, cols);

    while (true) {
        while (!montauk::is_key_available()) montauk::yield();

        montauk::abi::KeyEvent ev;
        montauk::getkey(&ev);
        if (!ev.pressed) continue;

        if (ev.ascii == 'q' || (ev.ctrl && ev.ascii == 'q'))
            return -1;

        int sel = -1;
        if (ev.ascii >= '1' && ev.ascii <= '9') sel = ev.ascii - '1';
        else if (ev.ascii == '0') sel = 9;

        if (sel >= 0 && sel < count) return sel;
    }
}

// ---- Entry point ----

extern "C" void _start() {
    static char argbuf[1024];  // keep off stack (16KB limit)
    montauk::getargs(argbuf, sizeof(argbuf));
    const char* arg = skip_spaces(argbuf);

    if (*arg == '\0') {
        montauk::print("\033[1;36mwiki\033[0m - Wikipedia article viewer\n\n");
        montauk::print("Usage: wiki <title>          Show article summary\n");
        montauk::print("       wiki -f <title>       Show full article\n");
        montauk::print("       wiki -s <query>       Search for articles\n");
        montauk::print("\nExamples:\n");
        montauk::print("  wiki Linux\n");
        montauk::print("  wiki -f C programming language\n");
        montauk::print("  wiki -s operating system\n");
        montauk::exit(0);
    }

    // Parse mode flag
    Mode mode = MODE_SUMMARY;
    if (arg[0] == '-' && arg[1] == 'f' && (arg[2] == ' ' || arg[2] == '\0')) {
        mode = MODE_FULL;
        arg = skip_spaces(arg + 2);
    } else if (arg[0] == '-' && arg[1] == 's' && (arg[2] == ' ' || arg[2] == '\0')) {
        mode = MODE_SEARCH;
        arg = skip_spaces(arg + 2);
    } else if (arg[0] == '-' && arg[1] == 'd' && (arg[2] == ' ' || arg[2] == '\0')) {
        mode = MODE_DUMP;
        arg = skip_spaces(arg + 2);
    }

    if (*arg == '\0') {
        montauk::print("\033[1;31mError:\033[0m no article title or search query\n");
        montauk::exit(1);
    }

    // Trim trailing spaces from query
    static char query[512];
    int qlen = 0;
    while (arg[qlen] && qlen < 511) { query[qlen] = arg[qlen]; qlen++; }
    while (qlen > 0 && query[qlen - 1] == ' ') qlen--;
    query[qlen] = '\0';

    // Initialize: resolve DNS and load certs
    if (mode != MODE_DUMP)
        montauk::print("\033[1;33mConnecting to Wikipedia...\033[0m\n");

    g_serverIp = montauk::resolve(WIKI_HOST);
    if (g_serverIp == 0) {
        if (mode == MODE_DUMP) { montauk::print("\x01"); montauk::sleep_ms(100); montauk::exit(1); }
        montauk::print("\033[1;31mError:\033[0m could not resolve en.wikipedia.org\n");
        montauk::exit(1);
    }

    g_tas = tls::load_trust_anchors();
    if (g_tas.count == 0) {
        if (mode == MODE_DUMP) { montauk::print("\x01"); montauk::sleep_ms(100); montauk::exit(1); }
        montauk::print("\033[1;31mError:\033[0m no CA certificates loaded\n");
        montauk::exit(1);
    }

    // Allocate shared buffers
    char* respBuf = (char*)malloc(RESP_MAX);
    WikiLine* lines = (WikiLine*)malloc(MAX_LINES * sizeof(WikiLine));
    char* extractBuf = (char*)malloc(RESP_MAX);
    if (!respBuf || !lines || !extractBuf) {
        montauk::print("\033[1;31mError:\033[0m out of memory\n");
        montauk::exit(1);
    }

    if (mode == MODE_DUMP) {
        // ---- Dump mode: output raw JSON body for desktop GUI ----
        static char path[2048], encoded[1024];
        url_encode_title(query, encoded, sizeof(encoded));
        snprintf(path, sizeof(path),
            "/w/api.php?action=query&format=json&formatversion=2"
            "&prop=extracts&explaintext=1&titles=%s", encoded);

        int respLen = wiki_fetch(path, respBuf, RESP_MAX);
        if (respLen <= 0) {
            montauk::print("\x01");  // error sentinel
            montauk::sleep_ms(100);
            montauk::exit(1);
        }
        respBuf[respLen] = '\0';

        int headerEnd = find_header_end(respBuf, respLen);
        if (headerEnd < 0) {
            montauk::print("\x01");
            montauk::sleep_ms(100);
            montauk::exit(1);
        }

        int statusCode = parse_status_code(respBuf, headerEnd);
        if (statusCode == 404) {
            montauk::print("\x01");
            montauk::sleep_ms(100);
            montauk::exit(1);
        }

        // Output raw JSON body in chunks to avoid overflowing
        // the 4KB kernel ring buffer (parent polls at ~60fps)
        const char* body = respBuf + headerEnd;
        int bodyLen = respLen - headerEnd;
        static char chunk[2049];
        int sent = 0;
        while (sent < bodyLen) {
            int n = bodyLen - sent;
            if (n > 2048) n = 2048;
            for (int ci = 0; ci < n; ci++) chunk[ci] = body[sent + ci];
            chunk[n] = '\0';
            montauk::print(chunk);
            sent += n;
            if (sent < bodyLen) montauk::sleep_ms(20);
        }
        montauk::putchar('\x04');  // EOT sentinel
        // Brief delay so parent can drain the ring buffer before we exit
        montauk::sleep_ms(100);
        montauk::exit(0);
    } else if (mode == MODE_SEARCH) {
        // ---- Search mode ----
        static char path[2048], encoded[1024];
        url_encode_query(query, encoded, sizeof(encoded));
        snprintf(path, sizeof(path),
            "/w/api.php?action=opensearch&search=%s&limit=10&format=json",
            encoded);

        int respLen = wiki_fetch(path, respBuf, RESP_MAX);
        if (respLen <= 0) {
            montauk::print("\033[1;31mError:\033[0m no response from Wikipedia\n");
            montauk::exit(1);
        }
        respBuf[respLen] = '\0';

        int headerEnd = find_header_end(respBuf, respLen);
        if (headerEnd < 0) {
            montauk::print("\033[1;31mError:\033[0m malformed response\n");
            montauk::exit(1);
        }

        const char* body = respBuf + headerEnd;
        int bodyLen = respLen - headerEnd;

        static char titles[MAX_SEARCH_RESULTS][256];
        int titleCount = parse_search_titles(body, bodyLen, titles, MAX_SEARCH_RESULTS);

        if (titleCount == 0) {
            montauk::print("\033[33mNo results found for \"");
            montauk::print(query);
            montauk::print("\"\033[0m\n");
            montauk::exit(0);
        }

        int cols = 80, rows = 25;
        montauk::termsize(&cols, &rows);

        // Enter alternate screen for interactive search
        montauk::print("\033[?1049h");
        montauk::print("\033[?25l");

        bool searchRunning = true;
        while (searchRunning) {
            int sel = run_search(titles, titleCount, query, rows, cols);

            if (sel < 0) {
                searchRunning = false;
                break;
            }

            // Show loading message on search screen
            sb_reset();
            int infoRow = 6 + titleCount + 2;
            sb_cursor_to(infoRow, 3);
            sb_puts("\033[2K\033[1;33mFetching \"");
            sb_puts(titles[sel]);
            sb_puts("\"...\033[0m");
            sb_flush();

            // Fetch selected article summary
            static char articlePath[2048], articleEncoded[1024];
            url_encode_title(titles[sel], articleEncoded, sizeof(articleEncoded));
            snprintf(articlePath, sizeof(articlePath),
                "/api/rest_v1/page/summary/%s", articleEncoded);

            respLen = wiki_fetch(articlePath, respBuf, RESP_MAX);
            if (respLen <= 0) {
                sb_reset();
                sb_cursor_to(infoRow, 3);
                sb_puts("\033[2K\033[1;31mFetch failed. Press any key.\033[0m");
                sb_flush();
                while (!montauk::is_key_available()) montauk::yield();
                montauk::abi::KeyEvent ev; montauk::getkey(&ev);
                continue;
            }
            respBuf[respLen] = '\0';

            headerEnd = find_header_end(respBuf, respLen);
            if (headerEnd < 0) continue;

            int statusCode = parse_status_code(respBuf, headerEnd);
            body = respBuf + headerEnd;
            bodyLen = respLen - headerEnd;

            if (statusCode == 404) {
                sb_reset();
                sb_cursor_to(infoRow, 3);
                sb_puts("\033[2K\033[1;31mArticle not found. Press any key.\033[0m");
                sb_flush();
                while (!montauk::is_key_available()) montauk::yield();
                montauk::abi::KeyEvent ev; montauk::getkey(&ev);
                continue;
            }

            static char title[512], description[512];
            extract_json_string(body, bodyLen, "title", title, sizeof(title));
            extract_json_string(body, bodyLen, "description", description, sizeof(description));
            int extractLen = extract_json_string(body, bodyLen, "extract",
                                                  extractBuf, RESP_MAX - 1);

            if (extractLen > 0) {
                int totalLines = build_lines(lines, MAX_LINES,
                    title, description, extractBuf, extractLen, cols, false);
                // Run pager without alt screen (we're already in one)
                run_pager(lines, totalLines, title, "Summary", false);
            }
            // Loop back to re-render search results
        }

        // Exit alternate screen
        montauk::print("\033[?25h");
        montauk::print("\033[?1049l");

    } else {
        // ---- Summary or Full Article mode ----
        static char path[2048], encoded[1024];
        if (mode == MODE_SUMMARY) {
            url_encode_title(query, encoded, sizeof(encoded));
            snprintf(path, sizeof(path),
                "/api/rest_v1/page/summary/%s", encoded);
        } else {
            url_encode_title(query, encoded, sizeof(encoded));
            snprintf(path, sizeof(path),
                "/w/api.php?action=query&format=json&formatversion=2"
                "&prop=extracts&explaintext=1&titles=%s", encoded);
        }

        int respLen = wiki_fetch(path, respBuf, RESP_MAX);
        if (respLen <= 0) {
            montauk::print("\033[1;31mError:\033[0m no response from Wikipedia\n");
            montauk::exit(1);
        }
        respBuf[respLen] = '\0';

        int headerEnd = find_header_end(respBuf, respLen);
        if (headerEnd < 0) {
            montauk::print("\033[1;31mError:\033[0m malformed response\n");
            montauk::exit(1);
        }

        int statusCode = parse_status_code(respBuf, headerEnd);
        const char* body = respBuf + headerEnd;
        int bodyLen = respLen - headerEnd;

        if (statusCode == 404) {
            montauk::print("\033[1;31mArticle not found:\033[0m ");
            montauk::print(query);
            montauk::putchar('\n');
            montauk::exit(1);
        }

        static char title[512], description[512];
        extract_json_string(body, bodyLen, "title", title, sizeof(title));
        if (mode == MODE_SUMMARY)
            extract_json_string(body, bodyLen, "description", description, sizeof(description));
        else
            description[0] = '\0';

        int extractLen = extract_json_string(body, bodyLen, "extract",
                                              extractBuf, RESP_MAX - 1);

        if (extractLen == 0) {
            montauk::print("\033[1;31mArticle not found:\033[0m ");
            montauk::print(query);
            montauk::putchar('\n');
            montauk::exit(1);
        }

        int cols = 80;
        montauk::termsize(&cols, nullptr);

        int totalLines = build_lines(lines, MAX_LINES,
            title, description, extractBuf, extractLen,
            cols, mode == MODE_FULL);

        const char* modeLabel = (mode == MODE_FULL) ? "Full Article" : "Summary";
        run_pager(lines, totalLines, title, modeLabel, true);
    }

    montauk::exit(0);
}