# This file is part of NIT ( http://www.nitlanguage.org ).
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

# Basic catalog generator for Nit packages
#
# See: <http://nitlanguage.org/catalog/>
#
# The tool scans packages and generates the HTML files of a catalog.
#
# ## Features
#
# * [X] scan packages and their `.ini`
# * [X] generate lists of packages
# * [X] generate a page per package with the readme and most metadata
# * [ ] link/include/be included in the documentation
# * [ ] propose `related packages`
# * [X] show directory content (a la nitls)
# * [X] gather git information from the working directory
# * [ ] gather git information from the repository
# * [ ] gather package information from github
# * [ ] gather people information from github
# * [ ] reify people
# * [X] separate information gathering from rendering
# * [ ] move up information gathering in (existing or new) service modules
# * [X] add command line options
# * [ ] harden HTML (escaping, path injection, etc)
# * [ ] nitcorn server with RESTful API
#
# ## Issues and limitations
#
# The tool works likee the other tools and expects to find valid Nit source code in the directories
#
# * cruft and temporary files will be collected
# * missing source file (e.g. not yet generated by nitcc) will make information
#   incomplete (e.g. invalid module thus partial dependency and metrics)
#
# How to use the tool as the basis of a Nit code archive on the web usable with a package manager is not clear.
module catalog

import md5 # To get gravatar images
import counter # For statistics
import modelize # To process and count classes and methods

redef class MPackage
	# Return the associated metadata from the `ini`, if any
	fun metadata(key: String): nullable String
	do
		var ini = self.ini
		if ini == null then return null
		return ini[key]
	end

	# The consolidated list of tags
	var tags = new Array[String]

	# The list of maintainers
	var maintainers = new Array[String]

	# The list of contributors
	var contributors = new Array[String]

	# The date of the most recent commit
	var last_date: nullable String = null

	# The date of the oldest commit
	var first_date: nullable String = null
end

redef class Int
	# Returns `log(self+1)`. Used to compute score of packages
	fun score: Float do return (self+1).to_f.log
end

# The main class of the calatog generator that has the knowledge
class Catalog

	# The modelbuilder
	# used to access the files and count source lines of code
	var modelbuilder: ModelBuilder

	# Packages by tag
	var tag2proj = new MultiHashMap[String, MPackage]

	# Packages by category
	var cat2proj = new MultiHashMap[String, MPackage]

	# Packages by maintainer
	var maint2proj = new MultiHashMap[String, MPackage]

	# Packages by contributors
	var contrib2proj = new MultiHashMap[String, MPackage]

	# Dependency between packages
	var deps = new POSet[MPackage]

	# Number of modules by package
	var mmodules = new Counter[MPackage]

	# Number of classes by package
	var mclasses = new Counter[MPackage]

	# Number of methods by package
	var mmethods = new Counter[MPackage]

	# Number of line of code by package
	var loc = new Counter[MPackage]

	# Number of commits by package
	var commits = new Counter[MPackage]

	# Score by package
	#
	# The score is loosely computed using other metrics
	var score = new Counter[MPackage]

	# Scan, register and add a contributor to a package
	fun register_contrib(person: String, mpackage: MPackage)
	do
		var projs = contrib2proj[person]
		if not projs.has(mpackage) then projs.add mpackage
	end

	# Compute information for a package
	fun package_page(mpackage: MPackage)
	do
		var score = score[mpackage].to_f

		var mdoc = mpackage.mdoc_or_fallback
		if mdoc != null then
			score += 100.0
			score += mdoc.content.length.score
		end


		var tryit = mpackage.metadata("upstream.tryit")
		if tryit != null then
			score += 1.0
		end
		var apk = mpackage.metadata("upstream.apk")
		if apk != null then
			score += 1.0
		end

		var homepage = mpackage.metadata("upstream.homepage")
		if homepage != null then
			score += 5.0
		end
		var maintainer = mpackage.metadata("package.maintainer")
		if maintainer != null then
			score += 5.0
			register_contrib(maintainer, mpackage)
			mpackage.maintainers.add maintainer
			var projs = maint2proj[maintainer]
			if not projs.has(mpackage) then projs.add mpackage
		end
		var license = mpackage.metadata("package.license")
		if license != null then
			score += 5.0
		end

		var browse = mpackage.metadata("upstream.browse")
		if browse != null then
			score += 5.0
		end

		var tags = mpackage.metadata("package.tags")
		var ts = mpackage.tags
		if tags != null then
			for t in tags.split(",") do
				t = t.trim
				if t == "" then continue
				ts.add t
			end
		end
		if ts.is_empty then ts.add "none"
		if tryit != null then ts.add "tryit"
		if apk != null then ts.add "apk"
		for t in ts do
			tag2proj[t].add mpackage
		end
		var cat = ts.first
		cat2proj[cat].add mpackage
		score += ts.length.score

		if deps.has(mpackage) then
			score += deps[mpackage].greaters.length.score
			score += deps[mpackage].direct_greaters.length.score
			score += deps[mpackage].smallers.length.score
			score += deps[mpackage].direct_smallers.length.score
		end

		var contributors = mpackage.contributors
		var more_contributors = mpackage.metadata("package.more_contributors")
		if more_contributors != null then
			for c in more_contributors.split(",") do
				contributors.add c.trim
			end
		end
		if not contributors.is_empty then
			for c in contributors do
				register_contrib(c, mpackage)
			end
		end
		score += contributors.length.to_f

		var mmodules = 0
		var mclasses = 0
		var mmethods = 0
		var loc = 0
		for g in mpackage.mgroups do
			mmodules += g.mmodules.length
			for m in g.mmodules do
				var am = modelbuilder.mmodule2node(m)
				if am != null then
					var file = am.location.file
					if file != null then
						loc += file.line_starts.length - 1
					end
				end
				for cd in m.mclassdefs do
					mclasses += 1
					for pd in cd.mpropdefs do
						if not pd isa MMethodDef then continue
						mmethods += 1
					end
				end
			end
		end
		self.mmodules[mpackage] = mmodules
		self.mclasses[mpackage] = mclasses
		self.mmethods[mpackage] = mmethods
		self.loc[mpackage] = loc

		#score += mmodules.score
		score += mclasses.score
		score += mmethods.score
		score += loc.score

		self.score[mpackage] = score.to_i
	end

	# Collect more information on a package using the `git` tool.
	fun git_info(mpackage: MPackage)
	do
		var ini = mpackage.ini
		if ini == null then return

		# TODO use real git info
		#var repo = ini.get_or_null("upstream.git")
		#var branch = ini.get_or_null("upstream.git.branch")
		#var directory = ini.get_or_null("upstream.git.directory")

		var dirpath = mpackage.root.filepath
		if dirpath == null then return

		# Collect commits info
		var res = git_run("log", "--no-merges", "--follow", "--pretty=tformat:%ad;%aN <%aE>", "--", dirpath)
		var contributors = new Counter[String]
		var commits = res.split("\n")
		if commits.not_empty and commits.last == "" then commits.pop
		self.commits[mpackage] = commits.length
		for l in commits do
			var s = l.split_once_on(';')
			if s.length != 2 or s.last == "" then continue

			# Collect date of last and first commit
			if mpackage.last_date == null then mpackage.last_date = s.first
			mpackage.first_date = s.first

			# Count contributors
			contributors.inc(s.last)
		end
		for c in contributors.sort.reverse_iterator do
			mpackage.contributors.add c
		end

	end
end

# Execute a git command and return the result
fun git_run(command: String...): String
do
	# print "git {command.join(" ")}"
	var p = new ProcessReader("git", command...)
	var res = p.read_all
	p.close
	p.wait
	return res
end