package main

import (
	"bufio"
	"flag"
	"io"
	"log"
	"os"
	"path/filepath"
	"regexp"
	"sync"
	"sync/atomic"
)

const deliminer = ","
const SourceColor = Purple
const TargetColor = Yellow
const ErrorColor = Red
const ImportantColor = BRed
const DefaultColor = Reset
const PathColor = Green

var FileRegex, _ = regexp.Compile(`sync\.ya?ml$`)
var programName = os.Args[0]

func main() {
	recurse := flag.String("r", "", "recurse into directories")
	file := flag.String("f", "", "file to read instructions from")
	debug := flag.Bool("d", false, "debug")
	flag.Parse()

	if *debug {
		log.SetFlags(log.Lmicroseconds | log.Lshortfile)
		logFile, err := os.Create("cln.log")
		if err != nil {
			LogError("Error creating log file: %v", err)
			os.Exit(1)
		}
		logger := io.MultiWriter(os.Stdout, logFile)
		log.SetOutput(logger)
	} else {
		log.SetFlags(log.Lmicroseconds)
	}

	instructions := make(chan *LinkInstruction, 1000)
	status := make(chan error)

	// Check input sources in priority order
	switch {
	case *recurse != "":
		LogInfo("Recurse: %s", *recurse)
		go ReadFromFilesRecursively(*recurse, instructions, status)

	case *file != "":
		LogInfo("File: %s", *file)
		go ReadFromFile(*file, instructions, status, true)

	case len(flag.Args()) > 0:
		LogInfo("Reading from command line arguments")
		go ReadFromArgs(instructions, status)

	case IsPipeInput():
		LogInfo("Reading from stdin pipe")
		go ReadFromStdin(instructions, status)

	default:
		if _, err := os.Stat("sync.yaml"); err == nil {
			LogInfo("Using default sync.yaml file")
			go ReadFromFile("sync.yaml", instructions, status, true)
		} else if _, err := os.Stat("sync.yml"); err == nil {
			LogInfo("Using default sync.yml file")
			go ReadFromFile("sync.yml", instructions, status, true)
		} else {
			LogInfo("No input provided")
			LogInfo("Provide input as: ")
			LogInfo("Arguments - %s <source>,<target>,<force?>", programName)
			LogInfo("File - %s -f <file>", programName)
			LogInfo("YAML File - %s -f <file.yaml>", programName)
			LogInfo("Folder (finding sync files in folder recursively) - %s -r <folder>", programName)
			LogInfo("stdin - (cat <file> | %s)", programName)
			os.Exit(1)
		}
	}

	go func() {
		for {
			err, ok := <-status
			if !ok {
				break
			}
			if err != nil {
				LogError("%v", err)
			}
		}
	}()

	var instructionsDone int32 = 0
	var wg sync.WaitGroup
	for {
		instruction, ok := <-instructions
		if !ok {
			LogInfo("No more instructions to process")
			break
		}
		LogInfo("Processing: %s", instruction.String())
		status := make(chan error)
		go instruction.RunAsync(status)
		wg.Add(1)
		err := <-status
		if err != nil {
			LogError("Failed processing instruction: %v", err)
		}
		atomic.AddInt32(&instructionsDone, 1)
		wg.Done()
	}
	wg.Wait()
	if instructionsDone == 0 {
		LogInfo("No instructions were processed")
		os.Exit(1)
	}
	LogInfo("All done")
}

func IsPipeInput() bool {
	info, err := os.Stdin.Stat()
	if err != nil {
		return false
	}
	return info.Mode()&os.ModeNamedPipe != 0
}

func ReadFromFilesRecursively(input string, output chan *LinkInstruction, status chan error) {
	defer close(output)
	defer close(status)

	workdir, _ := os.Getwd()
	input = NormalizePath(input, workdir)
	LogInfo("Reading input from files recursively starting in %s", FormatPathValue(input))

	files := make(chan string, 128)
	fileStatus := make(chan error)
	var wg sync.WaitGroup
	go GetSyncFilesRecursively(input, files, fileStatus)
	go func() {
		wg.Wait()
		close(files)
	}()

	go func() {
		for {
			err, ok := <-fileStatus
			if !ok {
				break
			}
			if err != nil {
				LogError("Failed to get sync files recursively: %v", err)
				status <- err
			}
		}
	}()

	for {
		file, ok := <-files
		if !ok {
			LogInfo("No more files to process")
			break
		}
		wg.Add(1)
		go func() {
			defer wg.Done()
			LogInfo(file)
			file = NormalizePath(file, workdir)
			LogInfo("Processing file: %s", FormatPathValue(file))

			// This "has" to be done because instructions are resolved in relation to cwd
			fileDir := FileRegex.FindStringSubmatch(file)
			if fileDir == nil {
				LogError("Failed to extract directory from %s", FormatSourcePath(file))
				return
			}
			LogInfo("Changing directory to %s (for %s)",
				FormatPathValue(fileDir[1]),
				FormatPathValue(file))
			err := os.Chdir(fileDir[1])
			if err != nil {
				LogError("Failed to change directory to %s: %v",
					FormatSourcePath(fileDir[1]), err)
				return
			}
			ReadFromFile(file, output, status, false)
			// Don't return directory, stay where we are
			os.Chdir(workdir)
		}()
	}
}

func ReadFromFile(input string, output chan *LinkInstruction, status chan error, doclose bool) {
	if doclose {
		defer close(output)
		defer close(status)
	}

	input = NormalizePath(input, filepath.Dir(input))
	LogInfo("Reading input from file: %s", FormatPathValue(input))

	// Check if this is a YAML file
	if IsYAMLFile(input) {
		LogInfo("Parsing as YAML file")
		instructions, err := ParseYAMLFile(input, filepath.Dir(input))
		if err != nil {
			LogError("Failed to parse YAML file %s: %v",
				FormatSourcePath(input), err)
			status <- err
			return
		}

		for _, instruction := range instructions {
			instr := instruction // Create a copy to avoid reference issues
			LogInfo("Read YAML instruction: %s", instr.String())
			output <- &instr
		}
		return
	}
}

func ReadFromArgs(output chan *LinkInstruction, status chan error) {
	defer close(output)
	defer close(status)

	workdir, _ := os.Getwd()
	LogInfo("Reading input from args")
	for _, arg := range flag.Args() {
		instruction, err := ParseInstruction(arg, workdir)
		if err != nil {
			LogError("Error parsing arg '%s': %v", arg, err)
			continue
		}
		output <- &instruction
	}
}

func ReadFromStdin(output chan *LinkInstruction, status chan error) {
	defer close(output)
	defer close(status)

	workdir, _ := os.Getwd()
	LogInfo("Reading input from stdin")

	scanner := bufio.NewScanner(os.Stdin)
	for scanner.Scan() {
		line := scanner.Text()
		instruction, err := ParseInstruction(line, workdir)
		if err != nil {
			LogError("Error parsing line '%s': %v", line, err)
			continue
		}
		output <- &instruction
	}
	if err := scanner.Err(); err != nil {
		LogError("Error reading from stdin: %v", err)
		status <- err
		return
	}
}