package main

import (
	"flag"
	"fmt"
	"os"
	"runtime/pprof"
	"strings"
	"time"
)

var (
	katiLogFlag         bool
	makefileFlag        string
	dryRunFlag          bool
	jobsFlag            int
	cpuprofile          string
	heapprofile         string
	katiStatsFlag       bool
	loadJson            string
	saveJson            string
	loadGob             string
	saveGob             string
	syntaxCheckOnlyFlag bool
)

func parseFlags() {
	// TODO: Make this default and replace this by -d flag.
	flag.BoolVar(&katiLogFlag, "kati_log", false, "Verbose kati specific log")
	flag.StringVar(&makefileFlag, "f", "", "Use it as a makefile")

	flag.BoolVar(&dryRunFlag, "n", false, "Only print the commands that would be executed")

	flag.IntVar(&jobsFlag, "j", 1, "Allow N jobs at once.")

	flag.StringVar(&loadGob, "load", "", "")
	flag.StringVar(&saveGob, "save", "", "")
	flag.StringVar(&loadJson, "load_json", "", "")
	flag.StringVar(&saveJson, "save_json", "", "")

	flag.StringVar(&cpuprofile, "kati_cpuprofile", "", "write cpu profile to `file`")
	flag.StringVar(&heapprofile, "kati_heapprofile", "", "write heap profile to `file`")
	flag.BoolVar(&katiStatsFlag, "kati_stats", false, "Show a bunch of statistics")
	flag.BoolVar(&syntaxCheckOnlyFlag, "c", false, "Syntax check only.")
	flag.Parse()
}

func parseCommandLine() ([]string, []string) {
	var vars []string
	var targets []string
	for _, arg := range flag.Args() {
		if strings.IndexByte(arg, '=') >= 0 {
			vars = append(vars, arg)
			continue
		}
		targets = append(targets, arg)
	}
	return vars, targets
}

func getBootstrapMakefile(targets []string) Makefile {
	bootstrap := `
CC:=cc
CXX:=g++
AR:=ar
MAKE:=kati
# Pretend to be GNU make 3.81, for compatibility.
MAKE_VERSION:=3.81
SHELL:=/bin/sh
# TODO: Add more builtin vars.

# http://www.gnu.org/software/make/manual/make.html#Catalogue-of-Rules
# The document above is actually not correct. See default.c:
# http://git.savannah.gnu.org/cgit/make.git/tree/default.c?id=4.1
.c.o:
	$(CC) $(CFLAGS) $(CPPFLAGS) $(TARGET_ARCH) -c -o $@ $<
.cc.o:
	$(CXX) $(CXXFLAGS) $(CPPFLAGS) $(TARGET_ARCH) -c -o $@ $<
# TODO: Add more builtin rules.
`
	bootstrap = fmt.Sprintf("%s\nMAKECMDGOALS:=%s\n", bootstrap, strings.Join(targets, " "))
	mk, err := ParseMakefileString(bootstrap, BootstrapMakefile, 0)
	if err != nil {
		panic(err)
	}
	return mk
}

func maybeWriteHeapProfile() {
	if heapprofile != "" {
		f, err := os.Create(heapprofile)
		if err != nil {
			panic(err)
		}
		pprof.WriteHeapProfile(f)
	}
}

func getDepGraph(clvars []string, targets []string) ([]*DepNode, Vars) {
	startTime := time.Now()

	if loadGob != "" {
		n, v := LoadDepGraph(loadGob)
		LogStats("deserialize time: %q", time.Now().Sub(startTime))
		return n, v
	}
	if loadJson != "" {
		n, v := LoadDepGraphFromJson(loadJson)
		LogStats("deserialize time: %q", time.Now().Sub(startTime))
		return n, v
	}

	bmk := getBootstrapMakefile(targets)

	var mk Makefile
	var err error
	if len(makefileFlag) > 0 {
		mk, err = ParseMakefile(makefileFlag)
	} else {
		mk, err = ParseDefaultMakefile()
	}
	if err != nil {
		panic(err)
	}

	for _, stmt := range mk.stmts {
		stmt.show()
	}

	mk.stmts = append(bmk.stmts, mk.stmts...)

	vars := make(Vars)
	for _, env := range os.Environ() {
		kv := strings.SplitN(env, "=", 2)
		Log("envvar %q", kv)
		if len(kv) < 2 {
			panic(fmt.Sprintf("A weird environ variable %q", kv))
		}
		vars.Assign(kv[0], RecursiveVar{
			expr:   literal(kv[1]),
			origin: "environment",
		})
	}
	vars.Assign("MAKEFILE_LIST", SimpleVar{value: []byte{}, origin: "file"})
	for _, v := range clvars {
		kv := strings.SplitN(v, "=", 2)
		Log("cmdlinevar %q", kv)
		if len(kv) < 2 {
			panic(fmt.Sprintf("unexpected command line var %q", kv))
		}
		vars.Assign(kv[0], RecursiveVar{
			expr:   literal(kv[1]),
			origin: "command line",
		})
	}

	er, err := Eval(mk, vars)
	if err != nil {
		panic(err)
	}

	vars.Merge(er.vars)

	LogStats("eval time: %q", time.Now().Sub(startTime))

	startTime = time.Now()
	db := NewDepBuilder(er, vars)
	LogStats("eval command prepare time: %q", time.Now().Sub(startTime))

	startTime = time.Now()
	nodes, err2 := db.Eval(targets)
	if err2 != nil {
		panic(err2)
	}
	LogStats("eval command time: %q", time.Now().Sub(startTime))
	return nodes, vars
}

func main() {
	parseFlags()
	if cpuprofile != "" {
		f, err := os.Create(cpuprofile)
		if err != nil {
			panic(err)
		}
		pprof.StartCPUProfile(f)
		defer pprof.StopCPUProfile()
	}
	defer maybeWriteHeapProfile()
	defer dumpStats()

	clvars, targets := parseCommandLine()

	nodes, vars := getDepGraph(clvars, targets)

	if saveGob != "" {
		startTime := time.Now()
		DumpDepGraph(nodes, vars, saveGob)
		LogStats("serialize time: %q", time.Now().Sub(startTime))
	}
	if saveJson != "" {
		startTime := time.Now()
		DumpDepGraphAsJson(nodes, vars, saveJson)
		LogStats("serialize time: %q", time.Now().Sub(startTime))
	}

	if syntaxCheckOnlyFlag {
		return
	}

	startTime := time.Now()
	ex := NewExecutor(vars)
	err := ex.Exec(nodes)
	if err != nil {
		panic(err)
	}
	LogStats("exec time: %q", time.Now().Sub(startTime))
}