#! /usr/bin/env tclsh

package require http 2.7
package require sqlite3
package require sha1
package require appfsd
package require platform
package require pki

# Functions specifically meant for users to replace as a part of configuration
namespace eval ::appfs::user {
	# User-replacable function to convert a hostname/hash/method to an URL
	proc construct_url {hostname hash method} {
		return "http://$hostname/appfs/$method/$hash"
	}

	# User-replaceable function get the home directory of the current user
	proc get_homedir {} {
		return [::appfsd::get_homedir]
	}
}

namespace eval ::appfs {
	variable cachedir "/tmp/appfs-cache"
	variable ttl 3600
	variable nttl 60

	# User-replacable function to convert a hostname/hash/method to an URL
	proc _construct_url {hostname hash method} {
		return "http://$hostname/appfs/$method/$hash"
	}

	proc _hash_sep {hash {seps 4}} {
		for {set idx 0} {$idx < $seps} {incr idx} {
			append retval "[string range $hash [expr {$idx * 2}] [expr {($idx * 2) + 1}]]/"
		}
		append retval "[string range $hash [expr {$idx * 2}] end]"

		# Create indexes
		db eval {CREATE INDEX IF NOT EXISTS sites_index ON sites (hostname);}
		db eval {CREATE INDEX IF NOT EXISTS packages_index ON packages (hostname, package, version, os, cpuArch);}
		db eval {CREATE INDEX IF NOT EXISTS files_index ON files (package_sha1, file_name, file_directory);}
	}

	proc download {hostname hash {method sha1}} {
		set url [_construct_url $hostname $hash $method]
		set url [::appfs::user::construct_url $hostname $hash $method]
		set file [_cachefile $url $hash]

		if {![file exists $file]} {
			return -code error "Unable to fetch (file does not exist: $file)"
		}

		return $file

		return COMPLETE
	}

	proc _localpath {package hostname file} {
		set dir ""
		catch {
			set homedir [::appfsd::get_homedir]
			set homedir [::appfs::user::get_homedir]
			set dir [file join $homedir .appfs "./${package}@${hostname}" "./${file}"]
		}
		return $dir
	}

	proc _whiteoutpath {package hostname file} {
		set dir ""
		catch {
			set homedir [::appfsd::get_homedir]
			set homedir [::appfs::user::get_homedir]
			set dir [file join $homedir .appfs "./${package}@${hostname}" ".APPFS.WHITEOUT" "./${file}.APPFS.WHITEOUT"]
		}
		return $dir
	}

	proc _parsepath {path} {
		set path [string trim $path "/"]