// Provides a seekdemo alias that allows fast-forwarding demo playback by a
// given time.
//
// Setup:
//
// Add "exec input-demoseeking.cfg" and the following cl_hook_gamestart_all
// hook to autoexec.cfg. If you already have a cl_hook_gamestart_all hook, add
// the quoted command to your hook, separated with a semicolon:
//
//     exec input-demoseeking.cfg
//     alias cl_hook_gamestart_all "demoseeking_game_started"
//
// Usage:
//     - start a demo (ply/playdemo command or menu)
//     - use ,. (comma and dot) keys to seek -5/+5 seconds
//     - use m/ (m and slash) keys to seek -30/+30 seconds, - (minus) also
//       works instead of slash
//     - or use the "seekdemo <seconds>" command directly
//
// Options (persisted):
//
// _demoseeking_min_speed
//     Minimum seek speed. Default 1.5.
// _demoseeking_max_speed
//     Maximum seek speed. Default 200. Reduce this if the client freezes too
//     much while seeking. If the framerate is still high while seeking, you
//     may increase this, but increasing this with low framerate is unlikely to
//     improve seek performance.
// _demoseeking_bind_keys
//     Whether to set default seekdemo bindings listed under "Usage" above.
//     Default 1. Set to 0 to disable the bindings.
//
// Variables:
//
// _demo_is_playing
//     Indicates whether a demo is currently playing. Set to 1 when playdemo
//     starts a demo.
//     Note: the setup above is needed to reset this reliably.
// _current_demo_name
//     The name of the latest played demo. Same as the argument passed to the
//     last playdemo command. If playdemo fails to start the demo (e.g. when
//     the file does not exist) this variable is not updated.
//     Note: the setup above is needed to reset this reliably.
// _demoseeking_is_seeking
//     1 while a seek is in progress, 0 otherwise.
//
// Extras:
//
// - The alias playdemo_hook is run when demo playback is started.
// - The alias seekdemo_hook_seek_end is run after a seek completed successfully.
// - The alias seekdemo_getseektime can be used by scripts to get the current
//   playback time or seek target time. See its usage below.

// state initialization
alias _demoseeking_init_vars "set _demoseeking_vars_loaded 1; set _demo_is_playing 0; set _current_demo_name \"\"; set _demoseeking_is_seeking 0; set _seekdemo_state idle; set _seekdemo_target 0; alias playdemo_hook \"\"; alias seekdemo_hook_seek_end"
alias _demoseeking_init_vars1 ""
_demoseeking_init_vars${_demoseeking_vars_loaded ?}

// option initialization (persistent)
alias _demoseeking_init_options "seta _demoseeking_options_loaded 1; seta _demoseeking_min_speed 1.5; seta _demoseeking_max_speed 200; seta _demoseeking_bind_keys 1"
alias _demoseeking_init_options1 ""
_demoseeking_init_options${_demoseeking_options_loaded ?}

// Hook into game start to reset seekdemo state. This prevents reloading the
// last demo when seekdemo is accidentally called during an actual game.
alias demoseeking_game_started "set _demo_is_playing 0; set _current_demo_name \"\""

// usage: seekdemo_getseektime <varname>
// Populates <varname> with the current seek target time, if seeking. If not
// seeking, populate it with the current playback time.
alias seekdemo_getseektime "_seekdemo_getseektime_get \"$1\" _seekdemo_getseektime_rpn_$_seekdemo_state"
alias _seekdemo_getseektime_get "cl_cmd rpn \"/$1\" ${$2} ="
set _seekdemo_getseektime_rpn_idle time
set _seekdemo_getseektime_rpn_starting _seekdemo_target
set _seekdemo_getseektime_rpn_seeking _seekdemo_target

// Hook into "playdemo" command. This alias runs immediately after the actual
// "playdemo" command runs. Needed for seekdemo to restart the demo when
// seeking backwards. Runs the playdemo_hook alias when a demo file is being
// loaded.
// ---
// "cl_cmd rpn" fails while a map is loading, leaving the value of
// _demoseeking_playdemo_success untouched, which means the playdemo command
// succeeded.
alias playdemo "set _demoseeking_playdemo_success 1; cl_cmd rpn /_demoseeking_playdemo_success 0 def; _demoseeking_playdemo_check \"$1\""
alias _demoseeking_playdemo_check "_demoseeking_playdemo_check_$_demoseeking_playdemo_success \"$1\""
alias _demoseeking_playdemo_check_0 "echo \"playdemo failed\""
alias _demoseeking_playdemo_check_1 "set _demo_is_playing 1; set _current_demo_name \"$1\"; playdemo_hook"

// Hook into the "defer" command to restore state when "defer clear" is run
// while seeking. "defer clear" seems to be run by some csprogs.
// ---
// compare the first argument. when it's "clear", run _demoseeking_restore
alias defer "alias _demoseeking_deftmp_$1 \"\"; alias _demoseeking_deftmp_clear _demoseeking_restore; _demoseeking_deftmp_$1; unalias _demoseeking_deftmp_$1"
alias _demoseeking_restore "_demoseeking_restore_$_seekdemo_state"
// idle - no seek, no state to restore
alias _demoseeking_restore_idle ""
// startseek - special state where this script calls defer clear before
// starting the seek loop
alias _demoseeking_restore_startseek ""
// starting - unexpected defer clear before seek started. Restore state by
// running check for forward/backward seek.
alias _demoseeking_restore_starting "_seekdemo_check_increasing"
// seeking - unexpected defer clear while seeking. Restart the loop.
alias _demoseeking_restore_seeking "_seekdemo_check_time"

// usage: seekdemo <seconds>
// Seek the playing demo by the number of seconds. May be a floating point
// number. The seek is asynchronous. When a seek is already in action, the
// target time is adjusted by the specified amount.
// When starting a seek backwards, the demo is restarted before forwarding to
// the earlier time. Does nothing when no demo is playing (_demo_is_playing).
// ---
alias seekdemo "set _seekdemo_demo_is_playing 0; cl_cmd rpn /_seekdemo_demo_is_playing _demo_is_playing 0 != def; _seekdemo_checkstart ${* q}"
// check if seek should start or if target time should be adjusted instead
alias _seekdemo_checkstart "_seekdemo_checkstart_$_seekdemo_demo_is_playing ${* q}"
alias _seekdemo_checkstart_0 "echo \"no demo currently playing\""
alias _seekdemo_checkstart_1 "_seekdemo_checkstate_$_seekdemo_state ${* q}"
// starting new seek. "dup" refers to the time value in the rpn command below
alias _seekdemo_checkstate_idle "_seekdemo_calc_target dup \"$1\"; set _demoseeking_is_seeking 1; set _seekdemo_state starting; _seekdemo_save_options; _seekdemo_check_increasing"
// when already seeking, only update the variable holding the target time
alias _seekdemo_checkstate_starting "_seekdemo_checkstate_seeking ${* q}"
alias _seekdemo_checkstate_seeking "_seekdemo_calc_target _seekdemo_target \"$1\""

// calculate target time and set _seekdemo_time_increasing according to the direction. args: <rpn-ref-time> <seconds>
alias _seekdemo_calc_target "cl_cmd rpn time $1 \"$2\" add dup /_seekdemo_target exch def le /_seekdemo_time_increasing exch def"

// check if seeking forwards or backwards
alias _seekdemo_check_increasing "_seekdemo_check_increasing_$_seekdemo_time_increasing"
// when seeking backwards, restart the demo and start the reload wait loop
alias _seekdemo_check_increasing_0 "playdemo \"$_current_demo_name\"; set _seekdemo_reload_success 1; cl_cmd rpn _seekdemo_reload_success 0 def; _seekdemo_check_reloading"
alias _seekdemo_check_increasing_1 "_seekdemo_check_time"
alias _seekdemo_check_reloading "_seekdemo_check_reloading_$_seekdemo_reload_success"
alias _seekdemo_check_reloading_0 "_seekdemo_failed (playdemo)"
// launch the "defer 10" command as a fallback to stop waiting in case demo reload fails
alias _seekdemo_check_reloading_1 "defer 10 \"_seekdemo_failed (reload)\"; _seekdemo_wait_reload"

// demo reload wait loop. "cl_cmd rpn" fails to execute until demo finished loading, leaving _demo_loaded 0
alias _seekdemo_wait_reload "set _demo_loaded 0; cl_cmd rpn /_demo_loaded 1 def; _seekdemo_check_loaded"
alias _seekdemo_check_loaded "_seekdemo_check_loaded_$_demo_loaded"
alias _seekdemo_check_loaded_0 "defer 0.02 _seekdemo_wait_reload"
// defer clear kills the fallback "defer 10" above
alias _seekdemo_check_loaded_1 "set _seekdemo_state startseek; defer clear; set _seekdemo_state seeking; _seekdemo_check_time"

// start of main seek loop, check if target time is reached
alias _seekdemo_check_time "set _seekdemo_seek_state failed; cl_cmd rpn _seekdemo_target time dup /_seekdemo_current_time exch def gt /_seekdemo_seek_state exch def; _seekdemo_check_continue"
alias _seekdemo_check_continue "_seekdemo_check_continue_$_seekdemo_seek_state"
alias _seekdemo_check_continue_0 "_seekdemo_leave_seek; seekdemo_hook_seek_end"
// Update options while seeking.
// - Adjust the playback speed by setting the slowmo cvar. The further the seek, the faster the playback speed.
// - Compare the speed to different speed levels to maximize performance for long seeks while reducing screen flashes for short ones.
// Then continue the loop with "defer 0", so the check is run on every rendered frame.
alias _seekdemo_check_continue_1 "set _seekdemo_speed_level failed; cl_cmd rpn _seekdemo_target time sub 10 mul _demoseeking_min_speed max _demoseeking_max_speed min dup /slowmo exch def dup 80 gt exch 2 gt add /_seekdemo_speed_level exch def; _seekdemo_set_options; defer 0 _seekdemo_check_time"
alias _seekdemo_check_continue_failed "_seekdemo_failed \"(demo ended?)\""

alias _seekdemo_failed "_seekdemo_leave_seek; echo SEEK FAILED ${1 ?}"

// Update options while and after seeking and for different levels of seek speed.
// - Disable r_render only at high seek speed to maximize performance, but keep
//   it enabled otherwise to avoid jarring black screens for short seeks.
// - snd_startnonloopingsounds disables all sounds that can safely be disabled,
//   avoiding lots of sounds playing at the same time.
// - Other disabled options prevent side effects from fast seeking at low
//   framerate, where particles and other effects accumulate and appear at the
//   same time when the target has been reached.
alias _seekdemo_leave_seek "_seekdemo_restore_options; set _demoseeking_is_seeking 0; set _seekdemo_state idle; r_render 1; snd_startnonloopingsounds 1; slowmo \"$_seekdemo_sav_slowmo\""
alias _seekdemo_set_options "_seekdemo_set_options_$_seekdemo_speed_level"
// speed level 0: below 2x playback speed, target almost reached, all options restored
alias _seekdemo_set_options_0 "r_render 1; snd_startnonloopingsounds 1; _seekdemo_restore_options"
// speed level 1: between 2x and 80x playback speed, sounds disabled, game rendered with reduced graphics
alias _seekdemo_set_options_1 "r_render 1; snd_startnonloopingsounds 0; _seekdemo_settemp_options"
// speed level 2: above 80x playback speed, sounds disabled, game not rendered to maximize performance
alias _seekdemo_set_options_2 "r_render 0; snd_startnonloopingsounds 0; _seekdemo_settemp_options"
// save/restore options for reduced settings
alias _seekdemo_save_options "set _seekdemo_sav_cl_decals \"$cl_decals\"; set _seekdemo_sav_cl_damagetext \"$cl_damagetext\"; set _seekdemo_sav_cl_particles \"$cl_particles\"; set _seekdemo_sav_cl_casings \"$cl_casings\"; set _seekdemo_sav_slowmo \"$slowmo\""
alias _seekdemo_settemp_options "settemp cl_decals 0; settemp cl_damagetext 0; settemp cl_particles 0; settemp cl_casings 0"
alias _seekdemo_restore_options "settemp cl_decals \"$_seekdemo_sav_cl_decals\"; settemp cl_damagetext \"$_seekdemo_sav_cl_damagetext\"; settemp cl_particles \"$_seekdemo_sav_cl_particles\"; settemp cl_casings \"$_seekdemo_sav_cl_casings\""

alias _demoseeking_bind_keys_0 ""
alias _demoseeking_bind_keys_1 "bind , \"seekdemo -5\"; bind . \"seekdemo +5\"; bind m \"seekdemo -30\"; bind - \"seekdemo +30\"; bind / \"seekdemo +30\""
_demoseeking_bind_keys_${_demoseeking_bind_keys ?}