#! /usr/bin/env tclsh

package require http 2.7
package require sqlite3
package require sha1

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]"

		# Force [parray] to be loaded
		catch {
			parray does_not_exist
		}

		set ::appfs::init_called 1

		# Load configuration file
		set config_file [file join $::appfs::cachedir config]
		if {[file exists $config_file]} {
			source $config_file
		}

		if {![info exists ::appfs::db]} {
			file mkdir $::appfs::cachedir

			sqlite3 ::appfs::db [file join $::appfs::cachedir cache.db]
		}

		# Create tables
		db eval {CREATE TABLE IF NOT EXISTS sites(hostname PRIMARY KEY, lastUpdate, ttl);}
		db eval {CREATE TABLE IF NOT EXISTS packages(hostname, sha1, package, version, os, cpuArch, isLatest, haveManifest);}
		db eval {CREATE TABLE IF NOT EXISTS files(package_sha1, type, time, source, size, perms, file_sha1, file_name, file_directory);}

		# 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 file [_cachefile $url $hash]

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

		return $file

				db eval {INSERT INTO files (package_sha1, type, time, source, size, perms, file_sha1, file_name, file_directory) VALUES ($package_sha1, $fileInfo(type), $fileInfo(time), $fileInfo(source), $fileInfo(size), $fileInfo(perms), $fileInfo(sha1), $fileInfo(name), $fileInfo(directory) );}
				db eval {UPDATE packages SET haveManifest = 1 WHERE sha1 = $package_sha1;}
			}
		}

		return COMPLETE
	}

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

		array set retval [list _children sites]

		if {$pathlen > 0} {
			set retval(hostname) [lindex $path 0]
			set retval(_children) packages

			if {$pathlen > 1} {
				set package [lindex $path 1]
				if {[string length $package] == "40" && [regexp {^[a-fA-F0-9]*$} $package]} {
					set retval(package_sha1) $package
					set retval(_children) files

					if {$pathlen > 2} {
						set retval(file) [join [lrange $path 2 end] "/"]
					} else {
						set retval(file) ""
					}

					return [array get retval]
				} else {
					set retval(package) $package
					set retval(_children) os-cpu
				}

				if {$pathlen > 2} {
					set os_cpu [lindex $path 2]
					set os_cpu [split $os_cpu "-"]

					set retval(os) [lindex $os_cpu 0]
					set retval(cpu) [lindex $os_cpu 1]
					set retval(_children) versions

					if {$pathlen > 3} {
						set retval(version) [lindex $path 3]
						set retval(_children) files

						set retval(package_sha1) [::appfs::db onecolumn {SELECT sha1 FROM packages WHERE hostname = $retval(hostname) AND os = $retval(os) AND cpuArch = $retval(cpu) AND version = $retval(version);}]
						if {$retval(package_sha1) == ""} {
							return [list]
						}

						if {$pathlen > 4} {
							set retval(file) [join [lrange $path 4 end] "/"]
						} else {
							set retval(file) ""
						}
					}
				}
			}
		}

		return [array get retval]
	}

	proc getchildren {dir} {
		array set pathinfo [_parsepath $dir]

		switch -- $pathinfo(_children) {
			"sites" {
				return [::appfs::db eval {SELECT DISTINCT hostname FROM packages;}]
			}
			"packages" {
				catch {
					::appfs::getindex $pathinfo(hostname)
				}

				return [::appfs::db eval {SELECT DISTINCT package FROM packages WHERE hostname = $pathinfo(hostname);}]
			}
			"os-cpu" {
				return [::appfs::db eval {SELECT DISTINCT os || "-" || cpuArch FROM packages WHERE hostname = $pathinfo(hostname) AND package = $pathinfo(package);}]
			}
			"versions" {
				return [::appfs::db eval {
					SELECT DISTINCT version FROM packages WHERE hostname = $pathinfo(hostname) AND package = $pathinfo(package) AND os = $pathinfo(os) AND cpuArch = $pathinfo(cpu);
				}]
			}
			"files" {
				catch {
					::appfs::getpkgmanifest $pathinfo(hostname) $pathinfo(package_sha1)
				}

				return [::appfs::db eval {SELECT DISTINCT file_name FROM files WHERE package_sha1 = $pathinfo(package_sha1) AND file_directory = $pathinfo(file);}]
			}
		}

		return -code error "Invalid or unacceptable path: $dir"
	}

	proc getattr {path} {
	}

	proc openpath {path mode} {
	}
}