Add initial Lua scripting support

This is preliminary. There are still tons of issues, and any aspect
of scripting may change in the future. I decided to merge this
(preliminary) work now because it makes it easier to develop it, not
because it's done. lua.rst is clear enough about it (plus some
sarcasm).

This requires linking to Lua. Lua has no official pkg-config file, but
there are distribution specific .pc files, all with different names.
Adding a non-pkg-config based configure test was considered, but we'd
rather not.

One major complication is that libquvi links against Lua too, and if
the Lua version is different from mpv's, you will get a crash as soon
as libquvi uses Lua. (libquvi by design always runs when a file is
opened.) I would consider this the problem of distros and whoever
builds mpv, but to make things easier for users, we add a terrible
runtime test to the configure script, which probes whether libquvi
will crash. This is disabled when cross-compiling, but in that case
we hope the user knows what he is doing.

12 files changed, 1017 insertions, 3 deletions

diff --git a/mpvcore/command.c b/mpvcore/command.c
index b30a5299e0..35e72cb3ad 100644
--- a/mpvcore/command.c
+++ b/mpvcore/command.c
@@ -68,6 +68,8 @@
 
 #include "mpvcore/mp_core.h"
 
+#include "mp_lua.h"
+
 static int edit_filters(struct MPContext *mpctx, enum stream_type mediatype,
                         const char *cmd, const char *arg);
 static int set_filters(struct MPContext *mpctx, enum stream_type mediatype,
@@ -1913,6 +1915,11 @@ static const m_option_t mp_properties[] = {
     {0},
 };
 
+const struct m_option *mp_get_property_list(void)
+{
+    return mp_properties;
+}
+
 int mp_property_do(const char *name, int action, void *val,
                    struct MPContext *ctx)
 {
@@ -2729,6 +2736,15 @@ void run_command(MPContext *mpctx, mp_cmd_t *cmd)
                          cmd->args[1].v.s, msg_osd);
         break;
 
+    case MP_CMD_SCRIPT_DISPATCH:
+        if (mpctx->lua_ctx) {
+#ifdef CONFIG_LUA
+            mp_lua_script_dispatch(mpctx, cmd->args[0].v.s, cmd->args[1].v.i,
+                            cmd->key_up_follows ? "keyup_follows" : "press");
+#endif
+        }
+        break;
+
     case MP_CMD_COMMAND_LIST: {
         for (struct mp_cmd *sub = cmd->args[0].v.p; sub; sub = sub->queue_next)
             run_command(mpctx, sub);
@@ -2755,3 +2771,59 @@ void run_command(MPContext *mpctx, mp_cmd_t *cmd)
         break;
     }
 }
+
+struct command_ctx {
+    int events;
+};
+
+void command_init(struct MPContext *mpctx)
+{
+    mpctx->command_ctx = talloc_zero(mpctx, struct command_ctx);
+}
+
+// Notify that a property might have changed.
+void mp_notify_property(struct MPContext *mpctx, const char *property)
+{
+    mp_notify(mpctx, MP_EVENT_PROPERTY, (void *)property);
+}
+
+void mp_notify(struct MPContext *mpctx, enum mp_event event, void *arg)
+{
+    struct command_ctx *ctx = mpctx->command_ctx;
+    ctx->events |= 1u << event;
+}
+
+static void handle_script_event(struct MPContext *mpctx, const char *name,
+                                const char *arg)
+{
+#ifdef CONFIG_LUA
+    mp_lua_event(mpctx, name, arg);
+#endif
+}
+
+void mp_flush_events(struct MPContext *mpctx)
+{
+    struct command_ctx *ctx = mpctx->command_ctx;
+
+    ctx->events |= (1u << MP_EVENT_TICK);
+
+    for (int n = 0; n < 16; n++) {
+        enum mp_event event = n;
+        unsigned mask = 1 << event;
+        if (ctx->events & mask) {
+            // The event handler could set event flags again; in this case let
+            // the next mp_flush_events() call handle it to avoid infinite loops.
+            ctx->events &= ~mask;
+            const char *name = NULL;
+            switch (event) {
+            case MP_EVENT_TICK:             name = "tick"; break;
+            case MP_EVENT_TRACKS_CHANGED:   name = "track-layout"; break;
+            case MP_EVENT_START_FILE:       name = "start"; break;
+            case MP_EVENT_END_FILE:         name = "end"; break;
+            default: ;
+            }
+            if (name)
+                handle_script_event(mpctx, name, "");
+        }
+    }
+}
diff --git a/mpvcore/command.h b/mpvcore/command.h
index 5ac8c3a8f0..1ac5b6f8f0 100644
--- a/mpvcore/command.h
+++ b/mpvcore/command.h
@@ -22,6 +22,8 @@
 struct MPContext;
 struct mp_cmd;
 
+void command_init(struct MPContext *mpctx);
+
 void mp_get_osd_mouse_pos(struct MPContext *mpctx, float *x, float *y);
 
 void run_command(struct MPContext *mpctx, struct mp_cmd *cmd);
@@ -30,4 +32,20 @@ void property_print_help(void);
 int mp_property_do(const char* name, int action, void* val,
                    struct MPContext *mpctx);
 
+const struct m_option *mp_get_property_list(void);
+
+enum mp_event {
+    MP_EVENT_NONE,
+    MP_EVENT_TICK,
+    MP_EVENT_PROPERTY,          // char*, property that is changed
+    MP_EVENT_TRACKS_CHANGED,
+    MP_EVENT_START_FILE,
+    MP_EVENT_END_FILE,
+};
+
+void mp_notify(struct MPContext *mpctx, enum mp_event event, void *arg);
+void mp_notify_property(struct MPContext *mpctx, const char *property);
+
+void mp_flush_events(struct MPContext *mpctx);
+
 #endif /* MPLAYER_COMMAND_H */
diff --git a/mpvcore/input/input.c b/mpvcore/input/input.c
index 902aa52b47..f624b8f5dd 100644
--- a/mpvcore/input/input.c
+++ b/mpvcore/input/input.c
@@ -229,6 +229,8 @@ static const mp_cmd_t mp_cmds[] = {
 
   { MP_CMD_VO_CMDLINE, "vo_cmdline", { ARG_STRING } },
 
+  { MP_CMD_SCRIPT_DISPATCH, "script_dispatch", { ARG_STRING, ARG_INT } },
+
   {0}
 };
 
@@ -528,6 +530,7 @@ struct input_ctx {
     // Autorepeat stuff
     short ar_state;
     int64_t last_ar;
+
     // Autorepeat config
     unsigned int ar_delay;
     unsigned int ar_rate;
@@ -1455,6 +1458,8 @@ static void remove_key_down(struct input_ctx *ictx, int code)
 static bool key_updown_ok(enum mp_command_type cmd)
 {
     switch (cmd) {
+    case MP_CMD_SCRIPT_DISPATCH:
+        return true;
     default:
         return false;
     }
diff --git a/mpvcore/input/input.h b/mpvcore/input/input.h
index f3ea895395..639f069a9c 100644
--- a/mpvcore/input/input.h
+++ b/mpvcore/input/input.h
@@ -85,6 +85,9 @@ enum mp_command_type {
     /// Video output commands
     MP_CMD_VO_CMDLINE,
 
+    /// Internal for Lua scripts
+    MP_CMD_SCRIPT_DISPATCH,
+
     // Internal
     MP_CMD_COMMAND_LIST, // list of sub-commands in args[0].v.p
 };
diff --git a/mpvcore/lua/assdraw.lua b/mpvcore/lua/assdraw.lua
new file mode 100644
index 0000000000..fc3b727f57
--- /dev/null
+++ b/mpvcore/lua/assdraw.lua
@@ -0,0 +1,98 @@
+local ass_mt = {}
+ass_mt.__index = ass_mt
+
+local function ass_new()
+    return setmetatable({ scale = 4, text = "" }, ass_mt)
+end
+
+function ass_mt.new_event(ass)
+    -- osd_libass.c adds an event per line
+    if #ass.text > 0 then
+        ass.text = ass.text .. "\n"
+    end
+end
+
+function ass_mt.draw_start(ass)
+    ass.text = string.format("%s{\\p%d}", ass.text, ass.scale)
+end
+
+function ass_mt.draw_stop(ass)
+    ass.text = ass.text .. "{\\p0}"
+end
+
+function ass_mt.coord(ass, x, y)
+    local scale = math.pow(2, ass.scale - 1)
+    local ix = math.ceil(x * scale)
+    local iy = math.ceil(y * scale)
+    ass.text = string.format("%s %d %d", ass.text, ix, iy)
+end
+
+function ass_mt.append(ass, s)
+    ass.text = ass.text .. s
+end
+
+function ass_mt.merge(ass1, ass2)
+    ass1.text = ass1.text .. ass2.text
+end
+
+function ass_mt.pos(ass, x, y)
+    ass:append(string.format("{\\pos(%f,%f)}", x, y))
+end
+
+function ass_mt.an(ass, an)
+    ass:append(string.format("{\\an%d}", an))
+end
+
+function ass_mt.move_to(ass, x, y)
+    ass:append(" m")
+    ass:coord(x, y)
+end
+
+function ass_mt.line_to(ass, x, y)
+    ass:append(" l")
+    ass:coord(x, y)
+end
+
+function ass_mt.bezier_curve(ass, x1, y1, x2, y2, x3, y3)
+    ass:append(" b")
+    ass:coord(x1, y1)
+    ass:coord(x2, y2)
+    ass:coord(x3, y3)
+end
+
+
+function ass_mt.rect_ccw(ass, x0, y0, x1, y1)
+    ass:move_to(x0, y0)
+    ass:line_to(x0, y1)
+    ass:line_to(x1, y1)
+    ass:line_to(x1, y0)
+end
+
+function ass_mt.rect_cw(ass, x0, y0, x1, y1)
+    ass:move_to(x0, y0)
+    ass:line_to(x1, y0)
+    ass:line_to(x1, y1)
+    ass:line_to(x0, y1)
+end
+
+function ass_mt.round_rect_cw(ass, x0, y0, x1, y1, r)
+    ass:move_to(x0 + r, y0)
+    ass:line_to(x1 - r, y0) -- top line
+    if r > 0 then
+        ass:bezier_curve(x1, y0, x1, y0, x1, y0 + r) -- top right corner
+    end
+    ass:line_to(x1, y1 - r) -- right line
+    if r > 0 then
+        ass:bezier_curve(x1, y1, x1, y1, x1 - r, y1) -- bottom right corner
+    end
+    ass:line_to(x0 + r, y1) -- bottom line
+    if r > 0 then
+        ass:bezier_curve(x0, y1, x0, y1, x0, y1 - r) -- bottom left corner
+    end
+    ass:line_to(x0, y0 + r) -- left line
+    if r > 0 then
+        ass:bezier_curve(x0, y0, x0, y0, x0 + r, y0) -- top left corner
+    end
+end
+
+return {ass_new = ass_new}
diff --git a/mpvcore/lua/defaults.lua b/mpvcore/lua/defaults.lua
new file mode 100644
index 0000000000..d24cda9cbe
--- /dev/null
+++ b/mpvcore/lua/defaults.lua
@@ -0,0 +1,82 @@
+
+local callbacks = {}
+-- each script has its own section, so that they don't conflict
+local default_section = "input_" .. mp.script_name
+
+-- Set the list of key bindings. These will override the user's bindings, so
+-- you should use this sparingly.
+-- A call to this function will remove all bindings previously set with this
+-- function. For example, set_key_bindings({}) would remove all script defined
+-- key bindings.
+-- Note: the bindings are not active by default. Use enable_key_bindings().
+--
+-- list is an array of key bindings, where each entry is an array as follow:
+--      {key, callback}
+--      {key, callback, callback_down}
+-- key is the key string as used in input.conf, like "ctrl+a"
+-- callback is a Lua function that is called when the key binding is used.
+-- callback_down can be given too, and is called when a mouse button is pressed
+-- if the key is a mouse button. (The normal callback will be for mouse button
+-- down.)
+--
+-- callback can be a string too, in which case the following will be added like
+-- an input.conf line: key .. " " .. callback
+-- (And callback_down is ignored.)
+function mp.set_key_bindings(list, section)
+    local cfg = ""
+    for i = 1, #list do
+        local entry = list[i]
+        local key = entry[1]
+        local cb = entry[2]
+        local cb_down = entry[3]
+        if type(cb) == "function" then
+            callbacks[#callbacks + 1] = {press=cb, before_press=cb_down}
+            cfg = cfg .. key .. " script_dispatch " .. mp.script_name
+                  .. " " .. #callbacks .. "\n"
+        else
+            cfg = cfg .. key .. " " .. cb .. "\n"
+        end
+    end
+    mp.input_define_section(section or default_section, cfg)
+end
+
+function mp.enable_key_bindings(section, flags)
+    mp.input_enable_section(section or default_section, flags)
+end
+
+function mp.disable_key_bindings(section)
+    mp.input_disable_section(section or default_section)
+end
+
+function mp.set_mouse_area(x0, y0, x1, y1, section)
+    mp.input_set_section_mouse_area(section or default_section, x0, y0, x1, y1)
+end
+
+-- called by C on script_dispatch input command
+function mp_script_dispatch(id, event)
+    local cb = callbacks[id]
+    if cb then
+        if event == "press" and cb.press then
+            cb.press()
+        elseif event == "keyup_follows" and cb.before_press then
+            cb.before_press()
+        end
+    end
+end
+
+mp.msg = {
+    log = mp.log,
+    fatal = function(...) return mp.log("fatal", ...) end,
+    error = function(...) return mp.log("error", ...) end,
+    warn = function(...) return mp.log("warn", ...) end,
+    info = function(...) return mp.log("info", ...) end,
+    verbose = function(...) return mp.log("verbose", ...) end,
+    debug = function(...) return mp.log("debug", ...) end,
+}
+
+_G.print = mp.msg.info
+
+package.loaded["mp"] = mp
+package.loaded["mp.msg"] = mp.msg
+
+return {}
diff --git a/mpvcore/mp_core.h b/mpvcore/mp_core.h
index 4b8a5fcef9..e15ec0355e 100644
--- a/mpvcore/mp_core.h
+++ b/mpvcore/mp_core.h
@@ -166,6 +166,8 @@ typedef struct MPContext {
     struct track **tracks;
     int num_tracks;
 
+    char *track_layout_hash;
+
     // Selected tracks. NULL if no track selected.
     struct track *current_track[STREAM_TYPE_COUNT];
 
@@ -291,10 +293,9 @@ typedef struct MPContext {
     bool drop_message_shown;
 
     struct screenshot_ctx *screenshot_ctx;
-
-    char *track_layout_hash;
-
+    struct command_ctx *command_ctx;
     struct encode_lavc_context *encode_lavc_ctx;
+    struct lua_ctx *lua_ctx;
 } MPContext;
 
 
diff --git a/mpvcore/mp_lua.c b/mpvcore/mp_lua.c
new file mode 100644
index 0000000000..ec63134673
--- /dev/null
+++ b/mpvcore/mp_lua.c
@@ -0,0 +1,678 @@
+#include <assert.h>
+#include <string.h>
+
+#include <lua.h>
+#include <lualib.h>
+#include <lauxlib.h>
+
+#include "talloc.h"
+
+#include "mp_common.h"
+#include "mp_lua.h"
+#include "mp_core.h"
+#include "mp_msg.h"
+#include "m_property.h"
+#include "m_option.h"
+#include "command.h"
+#include "input/input.h"
+#include "sub/sub.h"
+#include "osdep/timer.h"
+#include "path.h"
+#include "bstr.h"
+
+// List of builtin modules and their contents as strings.
+// All these are generated from mpvcore/lua/*.lua
+static const char *builtin_lua_scripts[][2] = {
+    {"mp.defaults",
+#   include "lua/defaults.inc"
+    },
+    {"mp.assdraw",
+#   include "lua/assdraw.inc"
+    },
+    {0}
+};
+
+// Represents a loaded script. Each has its own Lua state.
+struct script_ctx {
+    const char *name;
+    lua_State *state;
+    struct mp_log *log;
+    struct MPContext *mpctx;
+};
+
+struct lua_ctx {
+    struct script_ctx **scripts;
+    int num_scripts;
+};
+
+static struct script_ctx *find_script(struct lua_ctx *lctx, const char *name)
+{
+    for (int n = 0; n < lctx->num_scripts; n++) {
+        if (strcmp(lctx->scripts[n]->name, name) == 0)
+            return lctx->scripts[n];
+    }
+    return NULL;
+}
+
+static struct script_ctx *get_ctx(lua_State *L)
+{
+    lua_getfield(L, LUA_REGISTRYINDEX, "ctx");
+    struct script_ctx *ctx = lua_touserdata(L, -1);
+    lua_pop(L, 1);
+    assert(ctx);
+    return ctx;
+}
+
+static struct MPContext *get_mpctx(lua_State *L)
+{
+    return get_ctx(L)->mpctx;
+}
+
+static int wrap_cpcall(lua_State *L)
+{
+    lua_CFunction fn = lua_touserdata(L, -1);
+    lua_pop(L, 1);
+    return fn(L);
+}
+
+// Call the given function fn under a Lua error handler (similar to lua_cpcall).
+// Pass the given number of args from the Lua stack to fn.
+// Returns 0 (and empty stack) on success.
+// Returns LUA_ERR[RUN|MEM|ERR] otherwise, with the error value on the stack.
+static int mp_cpcall(lua_State *L, lua_CFunction fn, int args)
+{
+    // Don't use lua_pushcfunction() - it allocates memory on Lua 5.1.
+    // Instead, emulate C closures by making wrap_cpcall call fn.
+    lua_pushlightuserdata(L, fn); // args... fn
+    // Will always succeed if mp_lua_init() set it up correctly.
+    lua_getfield(L, LUA_REGISTRYINDEX, "wrap_cpcall"); // args... fn wrap_cpcall
+    lua_insert(L, -(args + 2)); // wrap_cpcall args... fn
+    return lua_pcall(L, args + 1, 0, 0);
+}
+
+static void report_error(lua_State *L)
+{
+    const char *err = lua_tostring(L, -1);
+    mp_msg(MSGT_CPLAYER, MSGL_WARN, "[lua] Error: %s\n",
+           err ? err : "[unknown]");
+    lua_pop(L, 1);
+}
+
+static void add_functions(struct script_ctx *ctx);
+
+static char *script_name_from_filename(void *talloc_ctx, struct lua_ctx *lctx,
+                                       const char *fname)
+{
+    fname = mp_basename(fname);
+    if (fname[0] == '@')
+        fname += 1;
+    char *name = talloc_strdup(talloc_ctx, fname);
+    // Drop .lua extension
+    char *dot = strrchr(name, '.');
+    if (dot)
+        *dot = '\0';
+    // Turn it into a safe identifier - this is used with e.g. dispatching
+    // input via: "send scriptname ..."
+    for (int n = 0; name[n]; n++) {
+        char c = name[n];
+        if (!(c >= 'A' && c <= 'Z') && !(c >= 'a' && c <= 'z') &&
+            !(c >= '0' && c <= '9'))
+            name[n] = '_';
+    }
+    // Make unique (stupid but simple)
+    while (find_script(lctx, name))
+        name = talloc_strdup_append(name, "_");
+    return name;
+}
+
+static int load_file(struct script_ctx *ctx, const char *fname)
+{
+    int r = 0;
+    lua_State *L = ctx->state;
+    if (luaL_loadfile(L, fname) || lua_pcall(L, 0, 0, 0)) {
+        report_error(L);
+        r = -1;
+    }
+    assert(lua_gettop(L) == 0);
+    return r;
+}
+
+static int load_builtin(lua_State *L)
+{
+    const char *name = luaL_checkstring(L, 1);
+    for (int n = 0; builtin_lua_scripts[n][0]; n++) {
+        if (strcmp(name, builtin_lua_scripts[n][0]) == 0) {
+            if (luaL_loadstring(L, builtin_lua_scripts[n][1]))
+                lua_error(L);
+            lua_call(L, 0, 1);
+            return 1;
+        }
+    }
+    return 0;
+}
+
+// Execute "require " .. name
+static bool require(lua_State *L, const char *name)
+{
+    char buf[80];
+    // Lazy, but better than calling the "require" function manually
+    snprintf(buf, sizeof(buf), "require '%s'", name);
+    if (luaL_loadstring(L, buf) || lua_pcall(L, 0, 0, 0)) {
+        report_error(L);
+        return false;
+    }
+    return true;
+}
+
+static void mp_lua_load_script(struct MPContext *mpctx, const char *fname)
+{
+    struct lua_ctx *lctx = mpctx->lua_ctx;
+    struct script_ctx *ctx = talloc_ptrtype(NULL, ctx);
+    *ctx = (struct script_ctx) {
+        .mpctx = mpctx,
+        .name = script_name_from_filename(ctx, lctx, fname),
+    };
+    char *log_name = talloc_asprintf(ctx, "lua/%s", ctx->name);
+    ctx->log = mp_log_new(ctx, mpctx->log, log_name);
+
+    lua_State *L = ctx->state = luaL_newstate();
+    if (!L)
+        goto error_out;
+
+    // used by get_ctx()
+    lua_pushlightuserdata(L, ctx); // ctx
+    lua_setfield(L, LUA_REGISTRYINDEX, "ctx"); // -
+
+    lua_pushcfunction(L, wrap_cpcall); // closure
+    lua_setfield(L, LUA_REGISTRYINDEX, "wrap_cpcall"); // -
+
+    luaL_openlibs(L);
+
+    lua_newtable(L); // mp
+    lua_pushvalue(L, -1); // mp mp
+    lua_setglobal(L, "mp"); // mp
+
+    add_functions(ctx); // mp
+
+    lua_pushstring(L, ctx->name); // mp name
+    lua_setfield(L, -2, "script_name"); // mp
+
+    lua_pop(L, 1); // -
+
+    // Add a preloader for each builtin Lua module
+    lua_getglobal(L, "package"); // package
+    assert(lua_type(L, -1) == LUA_TTABLE);
+    lua_getfield(L, -1, "preload"); // package preload
+    assert(lua_type(L, -1) == LUA_TTABLE);
+    for (int n = 0; builtin_lua_scripts[n][0]; n++) {
+        lua_pushcfunction(L, load_builtin); // package preload load_builtin
+        lua_setfield(L, -2, builtin_lua_scripts[n][0]);
+    }
+    lua_pop(L, 2); // -
+
+    assert(lua_gettop(L) == 0);
+
+    if (!require(L, "mp.defaults")) {
+        report_error(L);
+        goto error_out;
+    }
+
+    assert(lua_gettop(L) == 0);
+
+    if (fname[0] == '@') {
+        if (!require(L, fname))
+            goto error_out;
+    } else {
+        if (load_file(ctx, fname) < 0)
+            goto error_out;
+    }
+
+    MP_TARRAY_APPEND(lctx, lctx->scripts, lctx->num_scripts, ctx);
+    return;
+
+error_out:
+    if (ctx->state)
+        lua_close(ctx->state);
+    talloc_free(ctx);
+}
+
+static void kill_script(struct script_ctx *ctx)
+{
+    if (!ctx)
+        return;
+    struct lua_ctx *lctx = ctx->mpctx->lua_ctx;
+    lua_close(ctx->state);
+    for (int n = 0; n < lctx->num_scripts; n++) {
+        if (lctx->scripts[n] == ctx) {
+            MP_TARRAY_REMOVE_AT(lctx->scripts, lctx->num_scripts, n);
+            break;
+        }
+    }
+    talloc_free(ctx);
+}
+
+static const char *log_level[] = {
+    [MSGL_FATAL] = "fatal",
+    [MSGL_ERR] = "error",
+    [MSGL_WARN] = "warn",
+    [MSGL_INFO] = "info",
+    [MSGL_V] = "verbose",
+    [MSGL_DBG2] = "debug",
+};
+
+static int script_log(lua_State *L)
+{
+    struct script_ctx *ctx = get_ctx(L);
+
+    const char *level = luaL_checkstring(L, 1);
+    int msgl = -1;
+    for (int n = 0; n < MP_ARRAY_SIZE(log_level); n++) {
+        if (log_level[n] && strcasecmp(log_level[n], level) == 0) {
+            msgl = n;
+            break;
+        }
+    }
+    if (msgl < 0)
+        luaL_error(L, "Invalid log level '%s'", level);
+
+    int last = lua_gettop(L);
+    lua_getglobal(L, "tostring"); // args... tostring
+    for (int i = 2; i <= last; i++) {
+        lua_pushvalue(L, -1); // args... tostring tostring
+        lua_pushvalue(L, i); // args... tostring tostring args[i]
+        lua_call(L, 1, 1); // args... tostring str
+        const char *s = lua_tostring(L, -1);
+        if (s == NULL)
+            return luaL_error(L, "Invalid argument");
+        mp_msg_log(ctx->log, msgl, "%s%s", s, i > 0 ? " " : "");
+        lua_pop(L, 1);  // args... tostring
+    }
+    mp_msg_log(ctx->log, msgl, "\n");
+
+    return 0;
+}
+
+static int script_find_config_file(lua_State *L)
+{
+    const char *s = luaL_checkstring(L, 1);
+    char *path = mp_find_user_config_file(s);
+    if (path) {
+        lua_pushstring(L, path);
+    } else {
+        lua_pushnil(L);
+    }
+    talloc_free(path);
+    return 1;
+}
+
+static int run_event(lua_State *L)
+{
+    lua_getglobal(L, "mp_event"); // name arg mp_event
+    if (lua_isnil(L, -1))
+        return 0;
+    lua_insert(L, -3); // mp_event name arg
+    lua_call(L, 2, 0);
+    return 0;
+}
+
+void mp_lua_event(struct MPContext *mpctx, const char *name, const char *arg)
+{
+    // There is no proper subscription mechanism yet, so all scripts get it.
+    struct lua_ctx *lctx = mpctx->lua_ctx;
+    for (int n = 0; n < lctx->num_scripts; n++) {
+        struct script_ctx *ctx = lctx->scripts[n];
+        lua_State *L = ctx->state;
+        lua_pushstring(L, name);
+        if (arg) {
+            lua_pushstring(L, arg);
+        } else {
+            lua_pushnil(L);
+        }
+        if (mp_cpcall(L, run_event, 2) != 0)
+            report_error(L);
+    }
+}
+
+static int run_script_dispatch(lua_State *L)
+{
+    int id = lua_tointeger(L, 1);
+    const char *event = lua_tostring(L, 2);
+    lua_getglobal(L, "mp_script_dispatch");
+    if (lua_isnil(L, -1))
+        return 0;
+    lua_pushinteger(L, id);
+    lua_pushstring(L, event);
+    lua_call(L, 2, 0);
+    return 0;
+}
+
+void mp_lua_script_dispatch(struct MPContext *mpctx, char *script_name,
+                            int id, char *event)
+{
+    struct script_ctx *ctx = find_script(mpctx->lua_ctx, script_name);
+    if (!ctx) {
+        mp_msg(MSGT_CPLAYER, MSGL_V,
+               "Can't find script '%s' when handling input.\n", script_name);
+        return;
+    }
+    lua_State *L = ctx->state;
+    lua_pushinteger(L, id);
+    lua_pushstring(L, event);
+    if (mp_cpcall(L, run_script_dispatch, 2) != 0)
+        report_error(L);
+}
+
+static int script_send_command(lua_State *L)
+{
+    struct MPContext *mpctx = get_mpctx(L);
+    const char *s = luaL_checkstring(L, 1);
+
+    mp_cmd_t *cmd = mp_input_parse_cmd(bstr0((char*)s), "<lua>");
+    if (!cmd)
+        luaL_error(L, "error parsing command");
+    mp_input_queue_cmd(mpctx->input, cmd);
+
+    return 0;
+}
+
+static int script_property_list(lua_State *L)
+{
+    const struct m_option *props = mp_get_property_list();
+    lua_newtable(L);
+    for (int i = 0; props[i].name; i++) {
+        lua_pushinteger(L, i + 1);
+        lua_pushstring(L, props[i].name);
+        lua_settable(L, -3);
+    }
+    return 1;
+}
+
+static int script_property_string(lua_State *L)
+{
+    const struct m_option *props = mp_get_property_list();
+    struct MPContext *mpctx = get_mpctx(L);
+    const char *name = luaL_checkstring(L, 1);
+    int type = lua_tointeger(L, lua_upvalueindex(1))
+               ? M_PROPERTY_PRINT : M_PROPERTY_GET_STRING;
+
+    char *result = NULL;
+    if (m_property_do(props, name, type, &result, mpctx) >= 0 && result) {
+        lua_pushstring(L, result);
+        talloc_free(result);
+        return 1;
+    }
+    if (type == M_PROPERTY_PRINT) {
+        lua_pushstring(L, "");
+        return 1;
+    }
+    return 0;
+}
+
+static int script_set_osd_ass(lua_State *L)
+{
+    struct MPContext *mpctx = get_mpctx(L);
+    int res_x = luaL_checkinteger(L, 1);
+    int res_y = luaL_checkinteger(L, 2);
+    const char *text = luaL_checkstring(L, 3);
+    if (!mpctx->osd->external ||
+        strcmp(mpctx->osd->external, text) != 0 ||
+        mpctx->osd->external_res_x != res_x ||
+        mpctx->osd->external_res_y != res_y)
+    {
+        talloc_free(mpctx->osd->external);
+        mpctx->osd->external = talloc_strdup(mpctx->osd, text);
+        mpctx->osd->external_res_x = res_x;
+        mpctx->osd->external_res_y = res_y;
+        osd_changed(mpctx->osd, OSDTYPE_EXTERNAL);
+    }
+    return 0;
+}
+
+static int script_get_osd_resolution(lua_State *L)
+{
+    struct MPContext *mpctx = get_mpctx(L);
+    int w, h;
+    osd_object_get_resolution(mpctx->osd, mpctx->osd->objs[OSDTYPE_EXTERNAL],
+                              &w, &h);
+    lua_pushnumber(L, w);
+    lua_pushnumber(L, h);
+    return 2;
+}
+
+static int script_get_screen_size(lua_State *L)
+{
+    struct MPContext *mpctx = get_mpctx(L);
+    struct osd_object *obj = mpctx->osd->objs[OSDTYPE_EXTERNAL];
+    double aspect = 1.0 * obj->vo_res.w / MPMAX(obj->vo_res.h, 1) /
+                    obj->vo_res.display_par;
+    lua_pushnumber(L, obj->vo_res.w);
+    lua_pushnumber(L, obj->vo_res.h);
+    lua_pushnumber(L, aspect);
+    return 3;
+}
+
+static int script_get_mouse_pos(lua_State *L)
+{
+    struct MPContext *mpctx = get_mpctx(L);
+    float px, py;
+    mp_get_osd_mouse_pos(mpctx, &px, &py);
+    double sw, sh;
+    osd_object_get_scale_factor(mpctx->osd, mpctx->osd->objs[OSDTYPE_EXTERNAL],
+                                &sw, &sh);
+    lua_pushnumber(L, px * sw);
+    lua_pushnumber(L, py * sh);
+    return 2;
+}
+
+static int script_get_timer(lua_State *L)
+{
+    lua_pushnumber(L, mp_time_sec());
+    return 1;
+}
+
+static int script_get_chapter_list(lua_State *L)
+{
+    struct MPContext *mpctx = get_mpctx(L);
+    lua_newtable(L); // list
+    int num = get_chapter_count(mpctx);
+    for (int n = 0; n < num; n++) {
+        double time = chapter_start_time(mpctx, n);
+        char *name = chapter_display_name(mpctx, n);
+        lua_newtable(L); // list ch
+        lua_pushnumber(L, time); // list ch time
+        lua_setfield(L, -2, "time"); // list ch
+        lua_pushstring(L, name); // list ch name
+        lua_setfield(L, -2, "name"); // list ch
+        lua_pushinteger(L, n + 1); // list ch n1
+        lua_insert(L, -2); // list n1 ch
+        lua_settable(L, -3); // list
+        talloc_free(name);
+    }
+    return 1;
+}
+
+static const char *stream_type(enum stream_type t)
+{
+    switch (t) {
+    case STREAM_VIDEO: return "video";
+    case STREAM_AUDIO: return "audio";
+    case STREAM_SUB:   return "sub";
+    default:           return "unknown";
+    }
+}
+
+static int script_get_track_list(lua_State *L)
+{
+    struct MPContext *mpctx = get_mpctx(L);
+    lua_newtable(L); // list
+    for (int n = 0; n < mpctx->num_tracks; n++) {
+        struct track *track = mpctx->tracks[n];
+        lua_newtable(L); // list track
+
+        lua_pushstring(L, stream_type(track->type));
+        lua_setfield(L, -2, "type");
+        lua_pushinteger(L, track->user_tid);
+        lua_setfield(L, -2, "id");
+        lua_pushboolean(L, track->default_track);
+        lua_setfield(L, -2, "default");
+        lua_pushboolean(L, track->attached_picture);
+        lua_setfield(L, -2, "attached_picture");
+        if (track->lang) {
+            lua_pushstring(L, track->lang);
+            lua_setfield(L, -2, "language");
+        }
+        if (track->title) {
+            lua_pushstring(L, track->title);
+            lua_setfield(L, -2, "title");
+        }
+        lua_pushboolean(L, track->is_external);
+        lua_setfield(L, -2, "external");
+        if (track->external_filename) {
+            lua_pushstring(L, track->external_filename);
+            lua_setfield(L, -2, "external_filename");
+        }
+        lua_pushboolean(L, track->auto_loaded);
+        lua_setfield(L, -2, "auto_loaded");
+
+        lua_pushinteger(L, n + 1); // list track n1
+        lua_insert(L, -2); // list n1 track
+        lua_settable(L, -3); // list
+    }
+    return 1;
+}
+
+static int script_input_define_section(lua_State *L)
+{
+    struct MPContext *mpctx = get_mpctx(L);
+    char *section = (char *)luaL_checkstring(L, 1);
+    char *contents = (char *)luaL_checkstring(L, 2);
+    mp_input_define_section(mpctx->input, section, "<script>", contents, true);
+    return 0;
+}
+
+static int script_input_enable_section(lua_State *L)
+{
+    struct MPContext *mpctx = get_mpctx(L);
+    char *section = (char *)luaL_checkstring(L, 1);
+    char *sflags = (char *)luaL_optstring(L, 2, "");
+    bstr bflags = bstr0(sflags);
+    int flags = 0;
+    while (bflags.len) {
+        bstr val;
+        bstr_split_tok(bflags, "|", &val, &bflags);
+        if (bstr_equals0(val, "allow-hide-cursor")) {
+            flags |= MP_INPUT_ALLOW_HIDE_CURSOR;
+        } else if (bstr_equals0(val, "allow-vo-dragging")) {
+            flags |= MP_INPUT_ALLOW_VO_DRAGGING;
+        } else if (bstr_equals0(val, "exclusive")) {
+            flags |= MP_INPUT_EXCLUSIVE;
+        } else {
+            luaL_error(L, "invalid flag: '%.*s'", BSTR_P(val));
+        }
+    }
+    mp_input_enable_section(mpctx->input, section, flags);
+    return 0;
+}
+
+static int script_input_disable_section(lua_State *L)
+{
+    struct MPContext *mpctx = get_mpctx(L);
+    char *section = (char *)luaL_checkstring(L, 1);
+    mp_input_disable_section(mpctx->input, section);
+    return 0;
+}
+
+static int script_input_set_section_mouse_area(lua_State *L)
+{
+    struct MPContext *mpctx = get_mpctx(L);
+
+    doubl