From f816062f2ef82f70029ae4b5094b2ed7b01eb0f2 Mon Sep 17 00:00:00 2001
From: Aleksey Lobanov <i@likemath.ru>
Date: Sat, 3 Oct 2020 23:03:12 +0300
Subject: [PATCH] hw3: Simple ncurses

---
 03_TerminalProject/Makefile |   2 +
 03_TerminalProject/Show.c   | 139 ++++++++++++++++++++++++++++++++++++
 2 files changed, 141 insertions(+)
 create mode 100644 03_TerminalProject/Makefile
 create mode 100644 03_TerminalProject/Show.c

diff --git a/03_TerminalProject/Makefile b/03_TerminalProject/Makefile
new file mode 100644
index 0000000..c256ba8
--- /dev/null
+++ b/03_TerminalProject/Makefile
@@ -0,0 +1,2 @@
+all:
+	gcc Show.c -lncurses -O2 -o show
\ No newline at end of file
diff --git a/03_TerminalProject/Show.c b/03_TerminalProject/Show.c
new file mode 100644
index 0000000..499f946
--- /dev/null
+++ b/03_TerminalProject/Show.c
@@ -0,0 +1,139 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <curses.h>
+
+const int BUF_SIZE = 76;
+const int USER_KEY_ESCAPE = 27;
+const int WINDOW_COLS = 77;
+const int WINDOW_LINES = 19;
+
+void draw_window(WINDOW* scr,
+                 const int first_line,
+                 const char lines[WINDOW_LINES][BUF_SIZE],
+                 const int lines_count,
+                 const int shift_x,
+                 const int shift_y) {
+    wclear(scr);
+    box(scr, 0, 0);
+
+    for (int i = 0; i < lines_count; ++i) {
+        wmove(scr, i + shift_y, shift_x);
+        char out_str[BUF_SIZE];
+        snprintf(out_str, BUF_SIZE - 1, "%d: %s", i + first_line, lines[i]);
+        out_str[BUF_SIZE - 1] = '\0';
+        waddstr(scr, out_str);
+    }
+    wrefresh(scr);
+}
+
+void shift_lines(char lines[WINDOW_LINES][BUF_SIZE]) {
+    for (int i = 0; i < WINDOW_LINES - 1; ++i) {
+        strncpy(lines[i], lines[i + 1], BUF_SIZE);
+    }
+}
+
+// returns 1 on success line read, 0 if EOF reached
+int read_line(FILE* pFile, char line[BUF_SIZE]) {
+    char* res = fgets(line, BUF_SIZE, pFile);
+    if (res == NULL)
+        return 0;
+
+    char* pch = strchr(line, '\n');
+    if (pch != NULL) {
+        *pch = '\0';
+    } else {
+        // we need only first BUF_SIZE chars from each line
+        line[BUF_SIZE - 1] = '\0';
+        while (pch == NULL) {
+            char end_of_string[BUF_SIZE];
+            if (fgets(end_of_string, BUF_SIZE, pFile) == NULL)
+                break;
+            pch = strchr(end_of_string, '\n');
+        }
+    }
+    return 1;
+}
+
+int main(int argc, char** argv) {
+    FILE* pFile;
+    if (argc < 2) {
+        printf("You need to choose file to open: show INPUT_FILE\n");
+        return EXIT_FAILURE;
+    }
+    pFile = fopen(argv[1], "r");
+    if (pFile == NULL) {
+        printf("You need to choose correct file to open: show INPUT_FILE\n");
+        return EXIT_FAILURE;
+    }
+
+    char cur_lines[WINDOW_LINES][BUF_SIZE];
+    int total_lines = 0;
+    int current_line = 1;
+    int is_eof = 0;
+
+    // we need to read initial lines of file
+    for (int i = 0; i < WINDOW_LINES; ++i) {
+        char* line_buffer = cur_lines[i];
+
+        if (read_line(pFile, cur_lines[i])) {
+            total_lines += 1;
+        } else {
+            is_eof = 1;
+            break;
+        }
+    }
+
+    WINDOW* mainwin;
+    if ((mainwin = initscr()) == NULL) {
+        printf("Error initialising ncurses.\n");
+        exit(EXIT_FAILURE);
+    }
+    noecho();
+
+    wmove(mainwin, 0, 10);
+    waddstr(mainwin, argv[1]);
+    refresh();
+
+    WINDOW* source_window = newwin(WINDOW_LINES + 2, WINDOW_COLS, 2, 2);
+
+    draw_window(source_window, current_line, cur_lines, total_lines, 1, 1);
+    wrefresh(mainwin);
+
+    while (1) {
+        int ch = getch();
+        if (ch == ' ') {
+            if (is_eof && total_lines == 1) {
+                // last line -> exiting
+                break;
+            }
+            current_line += 1;
+            shift_lines(cur_lines);
+            total_lines -= 1;
+
+            if (!is_eof && read_line(pFile, cur_lines[WINDOW_LINES - 1])) {
+                total_lines += 1;
+            } else {
+                is_eof = 1;
+            }
+            wrefresh(mainwin);
+            draw_window(source_window, current_line, cur_lines, total_lines, 1,
+                        1);
+            wrefresh(mainwin);
+        } else if (ch == USER_KEY_ESCAPE) {
+            break;
+        }
+        refresh();
+    }
+
+    delwin(source_window);
+    delwin(mainwin);
+    endwin();
+
+    refresh();
+
+    fclose(pFile);
+
+    return EXIT_SUCCESS;
+}