Update

.vscode/launch.json

@@ -10,7 +10,7 @@
         "program": "${workspaceFolder}/bin/kilo",
         "args": [],
         "stopAtEntry": false,
-        "cwd": "${workspaceFolder}",
+        "cwd": "${workspaceFolder}/bin/",
         "environment": [],
         "externalConsole": true,
         "MIMode": "gdb",

.vscode/settings.json

@@ -1,2 +1,6 @@
 {
+    "files.associations": {
+        "time.h": "c",
+        "cstdarg": "c"
+    }
 }

CMakeFiles/kilo.dir/C.includecache

@@ -11,6 +11,8 @@ ctype.h
 -
 errno.h
 -
+stdarg.h
+-
 stdio.h
 -
 stdlib.h
@@ -19,8 +21,12 @@ string.h
 -
 sys/ioctl.h
 -
+sys/types.h
+-
 termios.h
 -
+time.h
+-
 unistd.h
 -
 

bin/Makefile

@@ -0,0 +1,178 @@
+# CMAKE generated file: DO NOT EDIT!
+# Generated by "Unix Makefiles" Generator, CMake Version 3.10
+
+# Default target executed when no arguments are given to make.
+default_target: all
+
+.PHONY : default_target
+
+# Allow only one "make -f Makefile2" at a time, but pass parallelism.
+.NOTPARALLEL:
+
+
+#=============================================================================
+# Special targets provided by cmake.
+
+# Disable implicit rules so canonical targets will work.
+.SUFFIXES:
+
+
+# Remove some rules from gmake that .SUFFIXES does not remove.
+SUFFIXES =
+
+.SUFFIXES: .hpux_make_needs_suffix_list
+
+
+# Suppress display of executed commands.
+$(VERBOSE).SILENT:
+
+
+# A target that is always out of date.
+cmake_force:
+
+.PHONY : cmake_force
+
+#=============================================================================
+# Set environment variables for the build.
+
+# The shell in which to execute make rules.
+SHELL = /bin/sh
+
+# The CMake executable.
+CMAKE_COMMAND = /usr/bin/cmake
+
+# The command to remove a file.
+RM = /usr/bin/cmake -E remove -f
+
+# Escaping for special characters.
+EQUALS = =
+
+# The top-level source directory on which CMake was run.
+CMAKE_SOURCE_DIR = /home/ayham-mamoun/Desktop/git/kilo
+
+# The top-level build directory on which CMake was run.
+CMAKE_BINARY_DIR = /home/ayham-mamoun/Desktop/git/kilo
+
+#=============================================================================
+# Targets provided globally by CMake.
+
+# Special rule for the target rebuild_cache
+rebuild_cache:
+	@$(CMAKE_COMMAND) -E cmake_echo_color --switch=$(COLOR) --cyan "Running CMake to regenerate build system..."
+	/usr/bin/cmake -H$(CMAKE_SOURCE_DIR) -B$(CMAKE_BINARY_DIR)
+.PHONY : rebuild_cache
+
+# Special rule for the target rebuild_cache
+rebuild_cache/fast: rebuild_cache
+
+.PHONY : rebuild_cache/fast
+
+# Special rule for the target edit_cache
+edit_cache:
+	@$(CMAKE_COMMAND) -E cmake_echo_color --switch=$(COLOR) --cyan "No interactive CMake dialog available..."
+	/usr/bin/cmake -E echo No\ interactive\ CMake\ dialog\ available.
+.PHONY : edit_cache
+
+# Special rule for the target edit_cache
+edit_cache/fast: edit_cache
+
+.PHONY : edit_cache/fast
+
+# The main all target
+all: cmake_check_build_system
+	$(CMAKE_COMMAND) -E cmake_progress_start /home/ayham-mamoun/Desktop/git/kilo/CMakeFiles /home/ayham-mamoun/Desktop/git/kilo/CMakeFiles/progress.marks
+	$(MAKE) -f CMakeFiles/Makefile2 all
+	$(CMAKE_COMMAND) -E cmake_progress_start /home/ayham-mamoun/Desktop/git/kilo/CMakeFiles 0
+.PHONY : all
+
+# The main clean target
+clean:
+	$(MAKE) -f CMakeFiles/Makefile2 clean
+.PHONY : clean
+
+# The main clean target
+clean/fast: clean
+
+.PHONY : clean/fast
+
+# Prepare targets for installation.
+preinstall: all
+	$(MAKE) -f CMakeFiles/Makefile2 preinstall
+.PHONY : preinstall
+
+# Prepare targets for installation.
+preinstall/fast:
+	$(MAKE) -f CMakeFiles/Makefile2 preinstall
+.PHONY : preinstall/fast
+
+# clear depends
+depend:
+	$(CMAKE_COMMAND) -H$(CMAKE_SOURCE_DIR) -B$(CMAKE_BINARY_DIR) --check-build-system CMakeFiles/Makefile.cmake 1
+.PHONY : depend
+
+#=============================================================================
+# Target rules for targets named kilo
+
+# Build rule for target.
+kilo: cmake_check_build_system
+	$(MAKE) -f CMakeFiles/Makefile2 kilo
+.PHONY : kilo
+
+# fast build rule for target.
+kilo/fast:
+	$(MAKE) -f CMakeFiles/kilo.dir/build.make CMakeFiles/kilo.dir/build
+.PHONY : kilo/fast
+
+kilo/kilo.o: kilo/kilo.c.o
+
+.PHONY : kilo/kilo.o
+
+# target to build an object file
+kilo/kilo.c.o:
+	$(MAKE) -f CMakeFiles/kilo.dir/build.make CMakeFiles/kilo.dir/kilo/kilo.c.o
+.PHONY : kilo/kilo.c.o
+
+kilo/kilo.i: kilo/kilo.c.i
+
+.PHONY : kilo/kilo.i
+
+# target to preprocess a source file
+kilo/kilo.c.i:
+	$(MAKE) -f CMakeFiles/kilo.dir/build.make CMakeFiles/kilo.dir/kilo/kilo.c.i
+.PHONY : kilo/kilo.c.i
+
+kilo/kilo.s: kilo/kilo.c.s
+
+.PHONY : kilo/kilo.s
+
+# target to generate assembly for a file
+kilo/kilo.c.s:
+	$(MAKE) -f CMakeFiles/kilo.dir/build.make CMakeFiles/kilo.dir/kilo/kilo.c.s
+.PHONY : kilo/kilo.c.s
+
+# Help Target
+help:
+	@echo "The following are some of the valid targets for this Makefile:"
+	@echo "... all (the default if no target is provided)"
+	@echo "... clean"
+	@echo "... depend"
+	@echo "... rebuild_cache"
+	@echo "... kilo"
+	@echo "... edit_cache"
+	@echo "... kilo/kilo.o"
+	@echo "... kilo/kilo.i"
+	@echo "... kilo/kilo.s"
+.PHONY : help
+
+
+
+#=============================================================================
+# Special targets to cleanup operation of make.
+
+# Special rule to run CMake to check the build system integrity.
+# No rule that depends on this can have commands that come from listfiles
+# because they might be regenerated.
+cmake_check_build_system:
+	$(CMAKE_COMMAND) -H$(CMAKE_SOURCE_DIR) -B$(CMAKE_BINARY_DIR) --check-build-system CMakeFiles/Makefile.cmake 0
+.PHONY : cmake_check_build_system
+

bin/kilo.c

@@ -0,0 +1,360 @@
+/*** includes ***/
+
+#define _DEFAULT_SOURCE
+#define _BSD_SOURCE
+#define _GNU_SOURCE
+
+#include <ctype.h>
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/ioctl.h>
+#include <sys/types.h>
+#include <termios.h>
+#include <unistd.h>
+
+/*** defines ***/
+
+#define KILO_VERSION "0.0.1"
+
+#define CTRL_KEY(k) ((k)&0x1f)
+
+enum editorKey {
+    ARROW_LEFT = 10000,
+    ARROW_RIGHT,
+    ARROW_UP,
+    ARROW_DOWN,
+    DEL_KEY,
+    HOME_KEY,
+    END_KEY,
+    PAGE_UP,
+    PAGE_DOWN,
+};
+
+/*** data ***/
+
+typedef struct erow {
+    int size;
+    char *chars;
+} erow;
+
+struct editorConfig {
+    int cx, cy;
+    int screenrows;
+    int screencols;
+    int numRows;
+    erow *row;
+    struct termios orig_termios;
+};
+
+struct editorConfig E;
+
+/*** terminal ***/
+
+void die(const char *s) {
+    write(STDOUT_FILENO, "\x1b[2J", 4);
+    write(STDOUT_FILENO, "\x1b[H", 3);
+
+    perror(s);
+    exit(1);
+}
+
+void disableRawMode() {
+    if (tcsetattr(STDIN_FILENO, TCSAFLUSH, &E.orig_termios) == 1)
+        die("tcsetattr");
+}
+
+void enableRawMode() {
+    if (tcgetattr(STDIN_FILENO, &E.orig_termios) == -1) die("tcgetattr");
+    atexit(disableRawMode);
+
+    struct termios raw = E.orig_termios;
+    raw.c_iflag &= ~(BRKINT | ICRNL | INPCK | ISTRIP | IXON);
+    raw.c_oflag &= ~(OPOST);
+    raw.c_cflag |= (CS8);
+    raw.c_lflag &= ~(ECHO | ICANON | IEXTEN | ISIG);
+
+    raw.c_cc[VMIN] = 0;
+    raw.c_cc[VTIME] = 1;
+
+    if (tcsetattr(STDIN_FILENO, TCSAFLUSH, &raw) == -1) die("tcsetattr");
+}
+
+int editorReadKey() {
+    int nread;
+    char c;
+    while ((nread = read(STDIN_FILENO, &c, 1)) != 1) {
+        if (nread == -1 && errno != EAGAIN) die("read");
+    }
+
+    if (c == '\x1b') {
+        char seq[3];
+
+        if (read(STDIN_FILENO, &seq[0], 1) != 1) return '\x1b';
+        if (read(STDIN_FILENO, &seq[1], 1) != 1) return '\x1b';
+
+        if (seq[0] == '[') {
+            if (seq[1] >= '0' && seq[1] <= '9') {
+                if (read(STDIN_FILENO, &seq[2], 1) != 1) return '\x1b';
+                if (seq[2] == '~') {
+                    switch (seq[1]) {
+                        case '1':
+                            return HOME_KEY;
+                        case '3':
+                            return DEL_KEY;
+                        case '4':
+                            return END_KEY;
+                        case '5':
+                            return PAGE_UP;
+                        case '6':
+                            return PAGE_DOWN;
+                        case '7':
+                            return HOME_KEY;
+                    }
+                }
+            } else {
+                switch (seq[1]) {
+                    case 'A':
+                        return ARROW_UP;
+                    case 'B':
+                        return ARROW_DOWN;
+                    case 'C':
+                        return ARROW_RIGHT;
+                    case 'D':
+                        return ARROW_LEFT;
+                    case 'H':
+                        return HOME_KEY;
+                    case 'F':
+                        return END_KEY;
+                }
+            }
+        } else if (seq[0] == 'O') {
+            switch (seq[1]) {
+                case 'H':
+                    return HOME_KEY;
+                case 'F':
+                    return END_KEY;
+            }
+        }
+
+        return '\x1b';
+    } else
+        return c;
+}
+
+int getCursorPosition(int *rows, int *cols) {
+    char buf[32];
+    unsigned int i = 0;
+
+    if (write(STDOUT_FILENO, "\x1b[6n", 4) != 4) return -1;
+
+    while (i < sizeof(buf) - 1) {
+        if (read(STDIN_FILENO, &buf[i], 1) != 1) break;
+        if (buf[i] == 'R') break;
+        i++;
+    }
+    buf[i] = '\0';
+
+    if (buf[0] != '\x1b' || buf[1] != '[') return -1;
+    if (sscanf(&buf[2], "%d;%d", rows, cols) != 2) return -1;
+
+    return 0;
+}
+
+int getWindowSize(int *rows, int *cols) {
+    struct winsize ws;
+
+    if (ioctl(STDOUT_FILENO, TIOCGWINSZ, &ws) == -1 || ws.ws_col == 0) {
+        if (write(STDOUT_FILENO, "\x1b[999C\x1b[999B", 12) != 12) return -1;
+        return getCursorPosition(rows, cols);
+    } else {
+        *cols = ws.ws_col;
+        *rows = ws.ws_row;
+        return 0;
+    }
+}
+
+/*** row operations ***/
+
+void editorAppendRow(char *s, size_t len) {
+    E.row = (erow *)realloc(E.row, sizeof(erow) * (E.numRows + 1));
+
+    int at = E.numRows;
+    E.row[at].size = len;
+    E.row[at].chars = (char *)malloc(len + 1);
+    memcpy(E.row[at].chars, s, len);
+    E.row[at].chars[len] = '\0';
+    E.numRows++;
+}
+
+/*** file i/o ***/
+
+void editorOpen(char *filename) {
+    FILE *fp = fopen(filename, "r");
+    if (!fp) die("fopen");
+
+    char *line = NULL;
+    size_t linecap = 0;
+    ssize_t linelen;
+    while ((linelen = getline(&line, &linecap, fp)) != -1) {
+        while (linelen > 0 &&
+               (line[linelen - 1] == '\n' || line[linelen - 1] == '\r'))
+            linelen--;
+        editorAppendRow(line, linelen);
+    }
+
+    free(line);
+    fclose(fp);
+}
+
+/*** append buffer ***/
+
+struct abuf {
+    char *b;
+    int len;
+};
+
+#define ABUF_INIT \
+    { NULL, 0 }
+
+void abAppend(struct abuf *ab, const char *s, int len) {
+    char *_new = (char *)realloc(ab->b, ab->len + len);
+
+    if (_new == NULL) return;
+    memcpy(&_new[ab->len], s, len);
+    ab->b = _new;
+    ab->len += len;
+}
+
+void abFree(struct abuf *ab) { free(ab->b); }
+
+/*** output ***/
+
+void editorDrawRows(struct abuf *ab) {
+    int y;
+    for (y = 0; y < E.screenrows; y++) {
+        if (y >= E.numRows) {
+            if (E.numRows == 0 && y == E.screenrows / 3) {
+                char welcome[80];
+                int welcomelen =
+                    snprintf(welcome, sizeof(welcome),
+                             "Kilo Editor -- version %s", KILO_VERSION);
+                if (welcomelen > E.screencols) welcomelen = E.screencols;
+                int padding = (E.screencols - welcomelen) / 2;
+                if (padding) {
+                    abAppend(ab, "~", 1);
+                    padding--;
+                }
+                while (padding--) abAppend(ab, " ", 1);
+                abAppend(ab, welcome, welcomelen);
+            } else {
+                abAppend(ab, "~", 1);
+            }
+        } else {
+            int len = E.row[y].size;
+            if (len > E.screencols) len = E.screencols;
+            abAppend(ab, E.row[y].chars, len);
+        }
+
+        abAppend(ab, "\x1b[K", 3);
+        if (y < E.screenrows - 1) {
+            abAppend(ab, "\r\n", 2);
+        }
+    }
+}
+
+void editorRefreshScreen() {
+    struct abuf ab = ABUF_INIT;
+
+    abAppend(&ab, "\x1b[?25l", 6);
+    abAppend(&ab, "\x1b[H", 3);
+
+    editorDrawRows(&ab);
+
+    char buf[32];
+    snprintf(buf, sizeof(buf), "\x1b[%d;%dH", E.cy + 1, E.cx + 1);
+    abAppend(&ab, buf, strlen(buf));
+
+    abAppend(&ab, "\x1b[?25h", 6);
+
+    write(STDOUT_FILENO, ab.b, ab.len);
+    abFree(&ab);
+}
+
+/*** input ***/
+
+void editorMoveCursor(int key) {
+    switch (key) {
+        case ARROW_LEFT:
+            if (E.cx != 0) E.cx--;
+            break;
+        case ARROW_RIGHT:
+            if (E.cx != E.screencols - 1) E.cx++;
+            break;
+        case ARROW_UP:
+            if (E.cy != 0) E.cy--;
+            break;
+        case ARROW_DOWN:
+            if (E.cy != E.screenrows - 1) E.cy++;
+            break;
+    }
+}
+
+void editorProcessKeypress() {
+    int c = editorReadKey();
+
+    switch (c) {
+        case CTRL_KEY('q'):
+            write(STDOUT_FILENO, "\x1b[2J", 4);
+            write(STDOUT_FILENO, "\x1b[H", 3);
+            exit(0);
+            break;
+
+        case HOME_KEY:
+            E.cx = 0;
+            break;
+        case END_KEY:
+            E.cx = E.screencols - 1;
+
+        case PAGE_UP:
+        case PAGE_DOWN: {
+            int times = E.screenrows;
+            while (times--)
+                editorMoveCursor(c == PAGE_UP ? ARROW_UP : ARROW_DOWN);
+        }
+
+        case ARROW_UP:
+        case ARROW_DOWN:
+        case ARROW_LEFT:
+        case ARROW_RIGHT:
+            editorMoveCursor(c);
+            break;
+    }
+}
+
+/*** init ***/
+
+void initEditor() {
+    E.cx = 0;
+    E.cy = 0;
+    E.numRows = NULL;
+
+    if (getWindowSize(&E.screenrows, &E.screencols) == -1) die("getWindowSize");
+}
+
+int main(int argc, char *argv[]) {
+    enableRawMode();
+    initEditor();
+
+    if (argc >= 2) {
+        editorOpen(argv[1]);
+    }
+
+    while (1) {
+        editorRefreshScreen();
+        editorProcessKeypress();
+    }
+
+    return 0;
+}

kilo/kilo.c

@@ -1,16 +1,25 @@
 /*** includes ***/
+
+#define _DEFAULT_SOURCE
+#define _BSD_SOURCE
+#define _GNU_SOURCE
+
 #include <ctype.h>
 #include <errno.h>
+#include <stdarg.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <sys/ioctl.h>
+#include <sys/types.h>
 #include <termios.h>
+#include <time.h>
 #include <unistd.h>
 
 /*** defines ***/
 
 #define KILO_VERSION "0.0.1"
+#define KILO_TAB_STOP 8
 
 #define CTRL_KEY(k) ((k)&0x1f)
 
@@ -28,10 +37,25 @@ enum editorKey {
 
 /*** data ***/
 
+typedef struct erow {
+    int size;
+    int rsize;
+    char *chars;
+    char *render;
+} erow;
+
 struct editorConfig {
     int cx, cy;
+    int rx;
+    int rowoff;
+    int coloff;
     int screenrows;
     int screencols;
+    int numRows;
+    erow *row;
+    char *filename;
+    char statusmsg[80];
+    time_t statusmsg_time;
     struct termios orig_termios;
 };
 
@@ -162,6 +186,80 @@ int getWindowSize(int *rows, int *cols) {
     }
 }
 
+/*** row operations ***/
+
+int editorRowCxToRx(erow *row, int cx) {
+    int rx = 0;
+    int j;
+    for (j = 0; j < cx; j++) {
+        if (row->chars[j] == '\t')
+            rx += (KILO_TAB_STOP - 1) - (rx % KILO_TAB_STOP);
+        rx++;
+    }
+    return rx;
+}
+
+void editorUpdateRow(erow *row) {
+    int tabs = 0;
+    int j;
+
+    for (j = 0; j < row->size; j++)
+        if (row->chars[j] == '\t') tabs++;
+
+    free(row->render);
+    row->render = (char *)malloc(row->size + tabs * (KILO_TAB_STOP - 1) + 1);
+
+    int idx = 0;
+    for (j = 0; j < row->size; j++) {
+        if (row->chars[j] == '\t') {
+            row->render[idx++] = ' ';
+            while (idx % KILO_TAB_STOP != 0) row->render[idx++] = ' ';
+        } else
+            row->render[idx++] = row->chars[j];
+    }
+    row->render[idx] = '\0';
+    row->rsize = idx;
+}
+
+void editorAppendRow(char *s, size_t len) {
+    E.row = (erow *)realloc(E.row, sizeof(erow) * (E.numRows + 1));
+
+    int at = E.numRows;
+    E.row[at].size = len;
+    E.row[at].chars = (char *)malloc(len + 1);
+    memcpy(E.row[at].chars, s, len);
+    E.row[at].chars[len] = '\0';
+
+    E.row[at].rsize = 0;
+    E.row[at].render = NULL;
+    editorUpdateRow(&E.row[at]);
+
+    E.numRows++;
+}
+
+/*** file i/o ***/
+
+void editorOpen(char *filename) {
+    free(E.filename);
+    E.filename = strdup(filename);
+
+    FILE *fp = fopen(filename, "r");
+    if (!fp) die("fopen");
+
+    char *line = NULL;
+    size_t linecap = 0;
+    ssize_t linelen;
+    while ((linelen = getline(&line, &linecap, fp)) != -1) {
+        while (linelen > 0 &&
+               (line[linelen - 1] == '\n' || line[linelen - 1] == '\r'))
+            linelen--;
+        editorAppendRow(line, linelen);
+    }
+
+    free(line);
+    fclose(fp);
+}
+
 /*** append buffer ***/
 
 struct abuf {
@@ -185,43 +283,99 @@ void abFree(struct abuf *ab) { free(ab->b); }
 
 /*** output ***/
 
-void editorDrawRows(struct abuf *ab) {
-    int y;
-    for (y = 0; y < E.screenrows; y++) {
-        if (y == E.screenrows / 3) {
-            char welcome[80];
-            int welcomelen =
-                snprintf(welcome, sizeof(welcome), "Kilo Editor -- version %s",
-                         KILO_VERSION);
-            if (welcomelen > E.screencols) welcomelen = E.screencols;
-            int padding = (E.screencols - welcomelen) / 2;
-            if (padding) {
-                abAppend(ab, "~", 1);
-                padding--;
-            }
-            while (padding--) abAppend(ab, " ", 1);
-            abAppend(ab, welcome, welcomelen);
-        } else {
-            abAppend(ab, "~", 1);
-        }
+void editorScroll() {
+    E.rx = E.cx;
 
-        abAppend(ab, "\x1b[K", 3);
-        if (y < E.screenrows - 1) {
-            abAppend(ab, "\r\n", 2);
-        }
+    if (E.cy < E.rowoff) {
+        E.rowoff = E.cy;
+    }
+    if (E.cy >= E.rowoff + E.screenrows) {
+        E.rowoff = E.cy - E.screenrows + 1;
+    }
+    if (E.rx < E.coloff) {
+        E.coloff = E.rx;
+    }
+    if (E.rx >= E.coloff + E.screencols) {
+        E.coloff = E.rx - E.screencols + 1;
     }
 }
 
+void editorDrawRows(struct abuf *ab) {
+    int y;
+    for (y = 0; y < E.screenrows; y++) {
+        int filerow = y + E.rowoff;
+        if (filerow >= E.numRows) {
+            if (E.numRows == 0 && y == E.screenrows / 3) {
+                char welcome[80];
+                int welcomelen =
+                    snprintf(welcome, sizeof(welcome),
+                             "Kilo Editor -- version %s", KILO_VERSION);
+                if (welcomelen > E.screencols) welcomelen = E.screencols;
+                int padding = (E.screencols - welcomelen) / 2;
+                if (padding) {
+                    abAppend(ab, "~", 1);
+                    padding--;
+                }
+                while (padding--) abAppend(ab, " ", 1);
+                abAppend(ab, welcome, welcomelen);
+            } else {
+                abAppend(ab, "~", 1);
+            }
+        } else {
+            int len = E.row[filerow].rsize - E.coloff;
+            if (len < 0) len = 0;
+            if (len > E.screencols) len = E.screencols;
+            abAppend(ab, &E.row[filerow].render[E.coloff], len);
+        }
+
+        abAppend(ab, "\x1b[K", 3);
+        abAppend(ab, "\r\n", 2);
+    }
+}
+
+void editorDrawStatusBar(struct abuf *ab) {
+    abAppend(ab, "\x1b[7m", 4);
+    char status[80], rstatus[80];
+    int len = snprintf(status, sizeof(status), "%.20s - %d lines",
+                       E.filename ? E.filename : "[No Name]", E.numRows);
+    int rlen = snprintf(rstatus, sizeof(rstatus), "%d/%d", E.cy + 1, E.numRows);
+    if (len > E.screencols) len = E.screencols;
+    abAppend(ab, status, len);
+    while (len < E.screencols) {
+        if (E.screencols - len == rlen) {
+            abAppend(ab, rstatus, rlen);
+            break;
+        } else {
+            abAppend(ab, " ", 1);
+            len++;
+        }
+    }
+    abAppend(ab, "\x1b[m", 3);
+}
+
+void editorDrawMessageBar(struct abuf *ab) {
+    abAppend(ab, "\x1b[K", 3);
+    int msglen = strlen(E.statusmsg);
+    if (msglen > E.screencols) msglen = E.screencols;
+    if (msglen && time(NULL) - E.statusmsg_time < 5)
+        abAppend(ab, E.statusmsg, msglen);
+}
+
 void editorRefreshScreen() {
+    editorScroll();
+
     struct abuf ab = ABUF_INIT;
 
     abAppend(&ab, "\x1b[?25l", 6);
     abAppend(&ab, "\x1b[H", 3);
 
     editorDrawRows(&ab);
+    editorDrawStatusBar(&ab);
+    editorDrawMessageBar(&ab);
 
     char buf[32];
-    snprintf(buf, sizeof(buf), "\x1b[%d;%dH", E.cy + 1, E.cx + 1);
+    snprintf(buf, sizeof(buf), "\x1b[%d;%dH", (E.cy - E.rowoff) + 1,
+             (E.rx - E.coloff) + 1);
     abAppend(&ab, buf, strlen(buf));
 
     abAppend(&ab, "\x1b[?25h", 6);
@@ -230,23 +384,49 @@ void editorRefreshScreen() {
     abFree(&ab);
 }
 
+void editorSetStatusMessage(const char *fmt, ...) {
+    va_list ap;
+    va_start(ap, fmt);
+    vsnprintf(E.statusmsg, sizeof(E.statusmsg), fmt, ap);
+    va_end(ap);
+    E.statusmsg_time = time(NULL);
+}
+
 /*** input ***/
 
 void editorMoveCursor(int key) {
+    erow *row = (E.cy >= E.numRows) ? NULL : &E.row[E.cy];
+
     switch (key) {
         case ARROW_LEFT:
-            if (E.cx != 0) E.cx--;
+            if (E.cx != 0)
+                E.cx--;
+            else if (E.cy > 0) {
+                E.cy--;
+                E.cx = E.row[E.cy].size;
+            }
             break;
         case ARROW_RIGHT:
-            if (E.cx != E.screencols - 1) E.cx++;
+            if (row && E.cx < row->size)
+                E.cx++;
+            else if (row && E.cx == row->size) {
+                E.cy++;
+                E.cx = 0;
+            }
             break;
         case ARROW_UP:
             if (E.cy != 0) E.cy--;
             break;
         case ARROW_DOWN:
-            if (E.cy != E.screenrows - 1) E.cy++;
+            if (E.cy < E.numRows - 1) E.cy++;
             break;
     }
+
+    row = (E.cy >= E.numRows) ? NULL : &E.row[E.cy];
+    int rowlen = row ? row->size : 0;
+    if (E.cx > rowlen) {
+        E.cx = rowlen;
+    }
 }
 
 void editorProcessKeypress() {
@@ -263,13 +443,17 @@ void editorProcessKeypress() {
             E.cx = 0;
             break;
         case END_KEY:
-            E.cx = E.screencols - 1;
+            if (E.cy < E.numRows) E.cx = E.row[E.cy].size;
+            break;
 
         case PAGE_UP:
         case PAGE_DOWN: {
-            int times = E.screenrows;
-            while (times--)
-                editorMoveCursor(c == PAGE_UP ? ARROW_UP : ARROW_DOWN);
+            if (c == PAGE_UP) {
+                E.cy = E.rowoff;
+            } else if (c == PAGE_DOWN) {
+                E.cy = E.rowoff + E.screenrows - 1;
+                if (E.cy > E.numRows) E.cy = E.numRows;
+            }
         }
 
         case ARROW_UP:
@@ -286,14 +470,30 @@ void editorProcessKeypress() {
 void initEditor() {
     E.cx = 0;
     E.cy = 0;
+    E.rx = 0;
+    E.rowoff = 0;
+    E.coloff = 0;
+    E.numRows = 0;
+    E.row = NULL;
+    E.filename = NULL;
+    E.statusmsg[0] = '\0';
+    E.statusmsg_time = 0;
 
     if (getWindowSize(&E.screenrows, &E.screencols) == -1) die("getWindowSize");
+    E.screenrows -= 2;
 }
 
-int main() {
+int main(int argc, char *argv[]) {
     enableRawMode();
     initEditor();
 
+    if (1 || argc >= 2) {
+        // editorOpen(argv[1]);
+        editorOpen("kilo.c");
+    }
+
+    editorSetStatusMessage("HELP: Ctrl-Q = quit");
+
     while (1) {
         editorRefreshScreen();
         editorProcessKeypress();