module custom;

import std.algorithm;
import std.array;
import std.conv;
import std.exception;
import std.file;
import std.getopt;
import std.path;
import std.stdio;
import std.string;

import ae.sys.d.manager;
import ae.utils.array;
import ae.utils.json;
import ae.utils.regex;

import common;
import config : config, subDir;
import install;
import repo;

alias indexOf = std..string.indexOf;

// https://issues.dlang.org/show_bug.cgi?id=15777
alias strip = std..string.strip;

alias subDir!"result" resultDir;

/// We save a JSON file to the result directory with the build parameters.
struct BuildInfo
{
	string diggerVersion;
	string spec;
	DiggerManager.Config.Build config;
	DManager.SubmoduleState components;
}

enum buildInfoFileName = "build-info.json";

void prepareResult()
{
	log("Moving...");
	if (resultDir.exists)
		resultDir.rmdirRecurse();
	rename(d.buildDir, resultDir);

	log("Build successful.\n\nTo start using it, run `digger install`, or add %s to your PATH.".format(
		resultDir.buildPath("bin").absolutePath()
	));
}

/// Build the customized D version.
/// The result will be in resultDir.
void runBuild(string spec, DManager.SubmoduleState submoduleState, bool asNeeded)
{
	auto buildInfoPath = buildPath(resultDir, buildInfoFileName);
	auto buildInfo = BuildInfo(diggerVersion, spec, d.config.build, submoduleState);
	if (asNeeded && buildInfoPath.exists && buildInfoPath.readText.jsonParse!BuildInfo == buildInfo)
	{
		log("Reusing existing version in " ~ resultDir);
		return;
	}
	d.build(submoduleState);
	prepareResult();
	std.file.write(buildInfoPath, buildInfo.toJson());
}

/// Perform an incremental build, i.e. don't clean or fetch anything from remote repos
void incrementalBuild()
{
	d.rebuild();
	prepareResult();
}

/// Run tests.
void runTests()
{
	d.test();
}

DManager.SubmoduleState parseSpec(string spec)
{
	auto parts = spec.split("+");
	parts = parts.map!strip().array();
	if (parts.empty)
		parts = [null];
	auto rev = parseRev(parts.shift());

	auto state = d.begin(rev);

	foreach (part; parts)
	{
		bool revert = part.skipOver("-");

		void apply(string component, string[2] branch, DManager.MergeMode mode)
		{
			if (revert)
				d.revert(state, component, branch, mode);
			else
				d.merge(state, component, branch, mode);
		}

		if (part.matchCaptures(re!`^(\w[\w\-\.]*)#(\d+)$`,
			(string component, int pull)
			{
				apply(component, d.getPull(component, pull), DManager.MergeMode.cherryPick);
			}))
			continue;

		if (part.matchCaptures(re!`^(?:([a-zA-Z0-9][a-zA-Z0-9\-]*[a-zA-Z0-9])/)?(\w[\w\-\.]*)/(?:(\w[\w\-]*)\.\.)?(\w[\w\-]*)$`,
			(string user, string component, string base, string tip)
			{
				// Some "do what I mean" logic here: if the user
				// specified a range, or a single commit, cherry-pick;
				// otherwise (just a branch name), do a git merge
				auto branch = d.getBranch(component, user, base, tip);
				auto mode = branch[0] ? DManager.MergeMode.cherryPick : DManager.MergeMode.merge;
				apply(component, branch, mode);
			}))
			continue;

		throw new Exception("Don't know how to apply customization: " ~ spec);
	}

	return state;
}

/// Build D according to the given spec string
/// (e.g. master+dmd#123).
void buildCustom(string spec, bool asNeeded = false)
{
	log("Building spec: " ~ spec);
	auto submoduleState = parseSpec(spec);
	runBuild(spec, submoduleState, asNeeded);
}

void checkout(string spec)
{
	log("Checking out: " ~ spec);
	auto submoduleState = parseSpec(spec);
	d.checkout(submoduleState);
	log("Done.");
}

/// Build all D versions (for the purpose of caching them).
/// Build order is in steps of decreasing powers of two.
void buildAll(string spec)
{
	d.needUpdate();
	auto commits = d.getLog("refs/remotes/origin/" ~ spec);
	commits.reverse(); // oldest first

	for (int step = 1 << 30; step; step >>= 1)
	{
		if (step >= commits.length)
			continue;

		log("Building all revisions with step %d (%d/%d revisions)".format(step, commits.length/step, commits.length));

		for (int n = step; n < commits.length; n += step)
			try
			{
				auto state = d.begin(commits[n].hash);
				if (!d.isCached(state))
				{
					log("Building revision %d/%d".format(n/step, commits.length/step));
					d.build(state);
				}
			}
			catch (Exception e)
				log(e.toString());
	}
}