/***************************************************************************************************
v0.1 07/08/2015: first release
v0.2 07/09/2015: correct normalization for loadings
v0.3 04/12/2017: correct weight
v0.4 09/01/2021: remove error when N < T + preserve tsset
v0.6 03/29/2026: fix cluster bootstrap. In previous versions, vce(bootstrap, cluster())
  silently ignored the absorb() option and used the wrong panel id for resampling when
  variable names were abbreviated. Point estimates from regife without bootstrap were
  unaffected. Standard errors from vce(bootstrap) without cluster() were also unaffected.
***************************************************************************************************/
program define regife, sortpreserve
	version 12.0
	syntax [varlist(min=1 numeric fv ts)] [if] [in] [aweight fweight pweight] , [Factors(string) ife(string) vce(string) Absorb(string) RESiduals(string) * ]

	if "`factors'" != ""{
		di as  txt "The option factors() was renamed to ife(). In the future, please use the syntax ife(`factors') to specify the factor model."
		local ife `factors'
	}
	if "`ife'" == ""{
		di as error "option ife() required"
		exit 111
	}


	local optionlist `options'

	/* syntax absorb */
	while (regexm("`absorb'", "[ ][ ]+")) {
		local absorb : subinstr local absorb "  " " ", all
	}
	local absorb : subinstr local absorb " =" "=", all
	local absorb : subinstr local absorb "= " "=", all
	

	if "`residuals'" ~= ""{
		confirm new variable `residuals'
	}

	cap which reghdfe.ado
	if _rc {
		di as error "reghdfe.ado required: {stata ssc install reghdfe}"
		exit 111
	}


	tokenize `absorb'
	while "`1'" ~= ""{	 
		if regexm("`1'", "(.+)=(.+)"){
			cap confirm new variable `=regexs(1)'
			if _rc{
				if _rc == 198{
					di as error "variable `=regexs(1)' is not a valid name"
				}
				else if _rc == 110{
					di as error "variable `=regexs(1)' already defined"
				}
				exit 198
			}

			local absorbvars `absorbvars' `=regexs(2)'
		}
		else{
			local absorbvars `absorbvars' `1'
		}
		macro shift
	}

	/* syntax factors */
	if regexm("`ife'", "(.*),(.*)"){
		local factors  = regexs(1)
		local dimension = regexs(2)
	}
	else{
		di as error "dimensions should be specified within the option factors"
		exit 198
	}




	while (regexm("`factors'", "[ ][ ]+")) {
		local factors : subinstr local factors "  " " ", all
	}
	local factors : subinstr local factors " =" "=", all
	local factors : subinstr local factors "= " "=", all

	cap assert `: word count `factors'' == 2
	if _rc{
		di as error "There must be exactly two variables in the option factors"
		exit 198
	}

	forv i = 1/2{	 
		local f : word `i' of `factors'
		if regexm("`f'", "(.+)=(.+)"){
			local id`i'gen `=regexs(1)'
			local id`i' = regexs(2)
			forval d = 1/`dimension'{
				confirm new variable `id`i'gen'`d'
			}
		}
		else{
			local id`i' `f'
		}
		confirm var `id`i''
	}

	unab id1 : `id1'
	unab id2 : `id2'
	local id `id1'
	local time `id2'



	if ("`weight'"!=""){
		local wtype `weight'
		local wvar  `=subinstr("`exp'","=","", .)'
	}


	/* touse */
	marksample touse
	markout `touse' `id' `time' `wvar', strok

	/*syntax varlist */  
	fvrevar `varlist' if `touse'
	local varlist = r(varlist)
	foreach v in `varlist'{
		local tvar : char `v'[tsrevar]
		local fvar : char `v'[fvrevar]
		if "`tvar'`fvar'" ~=""{
			local namelist `namelist'  `tvar'`fvar'
		}
		else{
			local namelist `namelist' `v'
		}
	}
	tokenize `varlist'
	local y `1'
	macro shift 
	local x `*'
	tokenize `namelist'
	local yname `1'
	macro shift 
	local xname `*'


	* syntax errors
	if "`vce'" ~= ""{
		local 0 `vce'
		syntax anything [, CLuster(varname) *]
		if "`anything'" == "bootstrap"{
			local bootstrap "yes"
			local bootstrapoptions `options'
		}
	}


	* mean weight
	if "`wvar'" ~= ""{
		tempvar wvar2
		qui bys `touse' `id': gen double `wvar2' = sum(`wvar') if `touse'
		qui by `touse' `id': replace `wvar2' = `wvar2'[_N]/_N if `touse'
		local wvar = "`wvar2'"
	}


	if "`bootstrap'" ~= "yes" {
		innerregife, dimension(`dimension') id(`id') time(`time') idgen(`id1gen') timegen(`id2gen') resgen(`residuals') y(`y') x(`x') yname(`yname') xname(`xname') touse(`touse') wtype(`wtype') wvar(`wvar')  absorbvars(`absorbvars') absorb(`absorb') vce(`vce')  `optionlist'
	}
	else{
		/* get bstart */
		qui innerregife, dimension(`dimension') id(`id') time(`time') idgen(`id1gen') timegen(`id2gen') resgen(`resgen') y(`y') x(`x') yname(`yname') xname(`xname') touse(`touse') wtype(`wtype') wvar(`wvar')  absorbvars(`absorbvars') absorb(`absorb')  `optionlist' 
		tempname bstart
		matrix `bstart' = e(bend)
		if "`cluster'" == ""{
			bootstrap,  `bootstrapoptions' : ///
			innerregife, dimension(`dimension') id(`id') time(`time') y(`y') x(`x') yname(`yname') xname(`xname') touse(`touse') wtype(`wtype') wvar(`wvar') absorb(`absorb') absorbvars(`absorbvars') fast bstart(`bstart') `optionlist'
		}
		else{
			tempvar clusterid
			cap tsset
			cap local tssettimevar = r(timevar)
			cap local tssetpanelvar = r(panelvar)
			tsset, clear
			if "`id'" == "`cluster'"{
				if "`absorbvars'" != "" {
					local absorbvars : subinstr local absorbvars "`id'" "`clusterid'", all
				}
				bootstrap, cluster(`cluster') idcluster(`clusterid') `bootstrapoptions': ///
				innerregife, dimension(`dimension') id(`clusterid') time(`time') y(`y') x(`x') yname(`yname') xname(`xname') touse(`touse') wtype(`wtype') wvar(`wvar') absorb(`absorb') absorbvars(`absorbvars')  fast bstart(`bstart') `optionlist'
			}
			else if "`time'" == "`cluster'"{
				if "`absorbvars'" != "" {
					local absorbvars : subinstr local absorbvars "`time'" "`clusterid'", all
				}
				bootstrap, cluster(`cluster') idcluster(`clusterid') `bootstrapoptions': ///
				innerregife, dimension(`dimension') id(`id') time(`clusterid') y(`y') x(`x') yname(`yname') xname(`xname') touse(`touse') wtype(`wtype') wvar(`wvar') absorb(`absorb') absorbvars(`absorbvars')  fast bstart(`bstart') `optionlist'
			}
			else{
				bootstrap, cluster(`cluster') idcluster(`clusterid') `bootstrapoptions': ///
				innerregife, dimension(`dimension') id(`id') time(`time') y(`y') x(`x') yname(`yname') xname(`xname') touse(`touse') wtype(`wtype') wvar(`wvar') absorb(`absorb') absorbvars(`absorbvars')  fast  bstart(`bstart')`optionlist'
			}
			if ("`tssettimevar'" != "") {
				tsset `tssetpanelvar' `tssettimevar' 
			}
		}
	}

end