package main

import (
	"flag"
	"fmt"
	"log"
	"os"
	"path/filepath"
	"sort"
	"sync"
	"time"

	"github.com/bmatcuk/doublestar/v4"
	"github.com/go-git/go-git/v5"
	"github.com/go-git/go-git/v5/plumbing/object"

	"modify/logger"
	"modify/processor"
)

type GlobalStats struct {
	TotalMatches       int
	TotalModifications int
	ProcessedFiles     int
	FailedFiles        int
}

var stats GlobalStats = GlobalStats{}

var (
	gitFlag       = flag.Bool("git", false, "Use git to manage files")
	resetFlag     = flag.Bool("reset", false, "Reset files to their original state")
	logLevel      = flag.String("loglevel", "INFO", "Set log level: ERROR, WARNING, INFO, DEBUG, TRACE")
	cookfile      = flag.String("cook", "**/cook.yml", "Path to cook config files, can be globbed")
	parallelfiles = flag.Int("P", 100, "Number of files to process in parallel")
	repo          *git.Repository
	worktree      *git.Worktree
)

type ModifyCommand struct {
	Pattern  string   `yaml:"pattern"`
	LuaExpr  string   `yaml:"lua"`
	Files    []string `yaml:"files"`
	Git      bool     `yaml:"git"`
	Reset    bool     `yaml:"reset"`
	LogLevel string   `yaml:"loglevel"`
}
type ReplaceCommand struct {
	From int
	To   int
	With string
}
type CookFile []ModifyCommand

func (c *ModifyCommand) Validate() error {
	if c.Pattern == "" {
		return fmt.Errorf("pattern is required")
	}
	if c.LuaExpr == "" {
		return fmt.Errorf("lua expression is required")
	}
	if len(c.Files) == 0 {
		return fmt.Errorf("at least one file is required")
	}
	if c.LogLevel == "" {
		c.LogLevel = "INFO"
	}
	return nil
}

func main() {
	flag.Usage = func() {
		fmt.Fprintf(os.Stderr, "Usage: %s [options] <pattern> <lua_expression> <...files_or_globs>\n", os.Args[0])
		fmt.Fprintf(os.Stderr, "\nOptions:\n")
		fmt.Fprintf(os.Stderr, "  -git\n")
		fmt.Fprintf(os.Stderr, "        Use git to manage files\n")
		fmt.Fprintf(os.Stderr, "  -reset\n")
		fmt.Fprintf(os.Stderr, "        Reset files to their original state\n")
		fmt.Fprintf(os.Stderr, "  -loglevel string\n")
		fmt.Fprintf(os.Stderr, "        Set logging level: ERROR, WARNING, INFO, DEBUG, TRACE (default \"INFO\")\n")
		fmt.Fprintf(os.Stderr, "\nExamples:\n")
		fmt.Fprintf(os.Stderr, "  Regex mode (default):\n")
		fmt.Fprintf(os.Stderr, "    %s \"<value>(\\d+)</value>\" \"*1.5\" data.xml\n", os.Args[0])
		fmt.Fprintf(os.Stderr, "\nNote: v1, v2, etc. are used to refer to capture groups as numbers.\n")
		fmt.Fprintf(os.Stderr, "      s1, s2, etc. are used to refer to capture groups as strings.\n")
		fmt.Fprintf(os.Stderr, "      Helper functions: num(str) converts string to number, str(num) converts number to string\n")
		fmt.Fprintf(os.Stderr, "      is_number(str) checks if a string is numeric\n")
		fmt.Fprintf(os.Stderr, "      If expression starts with an operator like *, /, +, -, =, etc., v1 is automatically prepended\n")
		fmt.Fprintf(os.Stderr, "      You can use any valid Lua code, including if statements, loops, etc.\n")
		fmt.Fprintf(os.Stderr, "      Glob patterns are supported for file selection (*.xml, data/**.xml, etc.)\n")
	}
	flag.Parse()
	args := flag.Args()

	level := logger.ParseLevel(*logLevel)
	logger.Init(level)
	logger.Info("Initializing with log level: %s", level.String())

	// The plan is:
	// Load all commands
	commands, err := LoadCommands(args)
	if err != nil {
		logger.Error("Failed to load commands: %v", err)
		flag.Usage()
		return
	}

	// Then aggregate all the globs and deduplicate them
	globs := AggregateGlobs(commands)

	// Resolve all the files for all the globs
	logger.Info("Found %d unique file patterns", len(globs))
	files, err := ExpandGLobs(globs)
	if err != nil {
		logger.Error("Failed to expand file patterns: %v", err)
		return
	}
	logger.Info("Found %d files to process", len(files))

	// Somehow connect files to commands via globs..
	// For each file check every glob of every command
	// Maybe memoize this part
	// That way we know what commands affect what files
	associations, err := AssociateFilesWithCommands(files, commands)
	if err != nil {
		logger.Error("Failed to associate files with commands: %v", err)
		return
	}

	// TODO: Utilize parallel workers for this
	// Then for each file run all commands associated with the file
	for file, commands := range associations {
		fileData, err := os.ReadFile(file)
		if err != nil {
			logger.Error("Failed to read file %q: %v", file, err)
			return
		}
		logger.Trace("Loaded %d bytes of data for file %q", len(fileData), file)
		fileDataStr := string(fileData)

		// Aggregate all the modifications and execute them
		modifications := []ReplaceCommand{}
		for _, command := range commands {
			logger.Info("Processing file %q with command %q", file, command.Pattern)
			// TODO: Run processor and return modifications
		}

		// Sort commands in reverse order for safe replacements
		sort.Slice(modifications, func(i, j int) bool {
			return modifications[i].From > modifications[j].From
		})
		logger.Trace("Applying %d replacement commands in reverse order", len(modifications))

		fileDataStr = ExecuteModifications(modifications, fileDataStr)

		err = os.WriteFile(file, []byte(fileDataStr), 0644)
		if err != nil {
			logger.Error("Failed to write file %q: %v", file, err)
			return
		}
	}

	// This will also relieve processor of some of the file loading
	// But we will also have to rework the tests.......
	// Also give each command its own logger, maybe prefix it with something... Maybe give commands a name?
	// Do that with logger.WithField("loglevel", level.String())
	// Since each command also has its own log level
	// TODO: Maybe even figure out how to run individual commands...?
	// TODO: What to do with git? Figure it out ....

	// if *gitFlag {
	// 	logger.Info("Git integration enabled, setting up git repository")
	// 	err := setupGit()
	// 	if err != nil {
	// 		logger.Error("Failed to setup git: %v", err)
	// 		fmt.Fprintf(os.Stderr, "Error setting up git: %v\n", err)
	// 		return
	// 	}
	// }

	// logger.Debug("Expanding file patterns")
	// files, err := expandFilePatterns(filePatterns)
	// if err != nil {
	// 	logger.Error("Failed to expand file patterns: %v", err)
	// 	fmt.Fprintf(os.Stderr, "Error expanding file patterns: %v\n", err)
	// 	return
	// }

	// if len(files) == 0 {
	// 	logger.Warning("No files found matching the specified patterns")
	// 	fmt.Fprintf(os.Stderr, "No files found matching the specified patterns\n")
	// 	return
	// }

	// if *gitFlag {
	// 	logger.Info("Cleaning up git files before processing")
	// 	err := cleanupGitFiles(files)
	// 	if err != nil {
	// 		logger.Error("Failed to cleanup git files: %v", err)
	// 		fmt.Fprintf(os.Stderr, "Error cleaning up git files: %v\n", err)
	// 		return
	// 	}
	// }
	// if *resetFlag {
	// 	logger.Info("Files reset to their original state, nothing more to do")
	// 	log.Printf("Files reset to their original state, nothing more to do")
	// 	return
	// }

	// Create the processor based on mode
	var proc processor.Processor = &processor.RegexProcessor{}

	var wg sync.WaitGroup
	log.Printf("%#v", proc)
	log.Printf("%#v", wg)
	// Process each file
	// for _, file := range files {
	// 	wg.Add(1)
	// 	logger.SafeGoWithArgs(func(args ...interface{}) {
	// 		defer wg.Done()
	// 		fileToProcess := args[0].(string)
	// 		logger.Debug("Processing file: %s", fileToProcess)

	// 		// It's a bit fucked, maybe I could do better to call it from proc... But it'll do for now
	// 		modCount, matchCount, err := processor.Process(proc, fileToProcess, pattern, luaExpr)
	// 		if err != nil {
	// 			logger.Error("Failed to process file %s: %v", fileToProcess, err)
	// 			fmt.Fprintf(os.Stderr, "Failed to process file %s: %v\n", fileToProcess, err)
	// 			stats.FailedFiles++
	// 		} else {
	// 			if modCount > 0 {
	// 				logger.Info("Successfully processed file %s: %d modifications from %d matches",
	// 					fileToProcess, modCount, matchCount)
	// 			} else if matchCount > 0 {
	// 				logger.Info("Found %d matches in file %s but made no modifications",
	// 					matchCount, fileToProcess)
	// 			} else {
	// 				logger.Debug("No matches found in file: %s", fileToProcess)
	// 			}
	// 			stats.ProcessedFiles++
	// 			stats.TotalMatches += matchCount
	// 			stats.TotalModifications += modCount
	// 		}
	// 	}, file)
	// }
	// wg.Wait()

	// Print summary
	if stats.TotalModifications == 0 {
		logger.Warning("No modifications were made in any files")
		fmt.Fprintf(os.Stderr, "No modifications were made in any files\n")
	} else {
		logger.Info("Operation complete! Modified %d values in %d/%d files",
			stats.TotalModifications, stats.ProcessedFiles, stats.ProcessedFiles+stats.FailedFiles)
		fmt.Printf("Operation complete! Modified %d values in %d/%d files\n",
			stats.TotalModifications, stats.ProcessedFiles, stats.ProcessedFiles+stats.FailedFiles)
	}
}

func ExecuteModifications(modifications []ReplaceCommand, fileData string) string {
	var err error
	for _, modification := range modifications {
		fileData, err = modification.Execute(fileData)
		if err != nil {
			logger.Error("Failed to execute modification: %v", err)
			continue
		}
	}
	return fileData
}

func (m *ReplaceCommand) Execute(fileDataStr string) (string, error) {
	err := m.Validate(len(fileDataStr))
	if err != nil {
		return "", fmt.Errorf("failed to validate modification: %v", err)
	}

	logger.Trace("Replace pos %d-%d with %q", m.From, m.To, m.With)
	return fileDataStr[:m.From] + m.With + fileDataStr[m.To:], nil
}

func (m *ReplaceCommand) Validate(maxsize int) error {
	if m.To < m.From {
		return fmt.Errorf("command to is less than from: %v", m)
	}
	if m.From > maxsize || m.To > maxsize {
		return fmt.Errorf("command from or to is greater than replacement length: %v", m)
	}
	return nil
}

func AssociateFilesWithCommands(files []string, commands []ModifyCommand) (map[string][]ModifyCommand, error) {
	associationCount := 0
	fileCommands := make(map[string][]ModifyCommand)
	for _, file := range files {
		for _, command := range commands {
			for _, glob := range command.Files {
				// TODO: Maybe memoize this function call
				matches, err := doublestar.Match(glob, file)
				if err != nil {
					logger.Trace("Failed to match glob %s with file %s: %v", glob, file, err)
					continue
				}
				if matches {
					logger.Debug("Found match for file %q and command %q", file, command.Pattern)
					fileCommands[file] = append(fileCommands[file], command)
					associationCount++
				}
			}
		}
		logger.Debug("Found %d commands for file %q", len(fileCommands[file]), file)
		if len(fileCommands[file]) == 0 {
			logger.Info("No commands found for file %q", file)
		}
	}
	logger.Info("Found %d associations between %d files and %d commands", associationCount, len(files), len(commands))
	return fileCommands, nil
}

func AggregateGlobs(commands []ModifyCommand) map[string]struct{} {
	logger.Info("Aggregating globs for %d commands", len(commands))
	globs := make(map[string]struct{})
	for _, command := range commands {
		for _, glob := range command.Files {
			globs[glob] = struct{}{}
		}
	}
	logger.Info("Found %d unique globs", len(globs))
	return globs
}

func LoadCommands(args []string) ([]ModifyCommand, error) {
	commands := []ModifyCommand{}

	logger.Info("Loading commands from cook files: %s", *cookfile)
	newcommands, err := LoadCommandsFromCookFiles(*cookfile)
	if err != nil {
		return nil, fmt.Errorf("failed to load commands from cook files: %w", err)
	}
	logger.Info("Successfully loaded %d commands from cook files", len(newcommands))
	commands = append(commands, newcommands...)
	logger.Info("Now total commands: %d", len(commands))

	logger.Info("Loading commands from arguments: %v", args)
	newcommands, err = LoadCommandFromArgs(args)
	if err != nil {
		return nil, fmt.Errorf("failed to load commands from args: %w", err)
	}
	logger.Info("Successfully loaded %d commands from args", len(newcommands))
	commands = append(commands, newcommands...)
	logger.Info("Now total commands: %d", len(commands))

	return commands, nil
}

func LoadCommandFromArgs(args []string) ([]ModifyCommand, error) {
	// Cannot reset without git, right?
	if *resetFlag {
		*gitFlag = true
	}

	if len(args) < 3 {
		return nil, fmt.Errorf("at least %d arguments are required", 3)
	}

	command := ModifyCommand{
		Pattern:  args[0],
		LuaExpr:  args[1],
		Files:    args[2:],
		Git:      *gitFlag,
		Reset:    *resetFlag,
		LogLevel: *logLevel,
	}

	if err := command.Validate(); err != nil {
		return nil, fmt.Errorf("invalid command: %w", err)
	}

	return []ModifyCommand{command}, nil
}

func LoadCommandsFromCookFiles(s string) ([]ModifyCommand, error) {
	return nil, nil
}

func setupGit() error {
	cwd, err := os.Getwd()
	if err != nil {
		return fmt.Errorf("failed to get current working directory: %w", err)
	}
	logger.Debug("Current working directory obtained: %s", cwd)

	logger.Debug("Attempting to open git repository at %s", cwd)
	repo, err = git.PlainOpen(cwd)
	if err != nil {
		logger.Debug("No existing git repository found at %s, attempting to initialize a new git repository.", cwd)
		repo, err = git.PlainInit(cwd, false)
		if err != nil {
			return fmt.Errorf("failed to initialize a new git repository at %s: %w", cwd, err)
		}
		logger.Info("Successfully initialized a new git repository at %s", cwd)
	} else {
		logger.Info("Successfully opened existing git repository at %s", cwd)
	}

	logger.Debug("Attempting to obtain worktree for repository at %s", cwd)
	worktree, err = repo.Worktree()
	if err != nil {
		return fmt.Errorf("failed to obtain worktree for repository at %s: %w", cwd, err)
	}
	logger.Debug("Successfully obtained worktree for repository at %s", cwd)
	return nil
}

func ExpandGLobs(patterns map[string]struct{}) ([]string, error) {
	var files []string
	filesMap := make(map[string]bool)

	cwd, err := os.Getwd()
	if err != nil {
		return nil, fmt.Errorf("failed to get current working directory: %w", err)
	}

	logger.Debug("Expanding patterns from directory: %s", cwd)
	for pattern, _ := range patterns {
		logger.Trace("Processing pattern: %s", pattern)
		matches, _ := doublestar.Glob(os.DirFS(cwd), pattern)
		logger.Debug("Found %d matches for pattern %s", len(matches), pattern)
		for _, m := range matches {
			info, err := os.Stat(m)
			if err != nil {
				logger.Warning("Error getting file info for %s: %v", m, err)
				continue
			}
			if !info.IsDir() && !filesMap[m] {
				logger.Trace("Adding file to process list: %s", m)
				filesMap[m], files = true, append(files, m)
			}
		}
	}

	if len(files) > 0 {
		logger.Debug("Found %d files to process: %v", len(files), files)
	}
	return files, nil
}

func cleanupGitFiles(files []string) error {
	for _, file := range files {
		logger.Debug("Checking git status for file: %s", file)
		status, err := worktree.Status()
		if err != nil {
			logger.Error("Error getting worktree status: %v", err)
			fmt.Fprintf(os.Stderr, "Error getting worktree status: %v\n", err)
			return fmt.Errorf("error getting worktree status: %w", err)
		}
		if status.IsUntracked(file) {
			logger.Info("Detected untracked file: %s. Adding to git index.", file)
			_, err = worktree.Add(file)
			if err != nil {
				logger.Error("Error adding file to git: %v", err)
				fmt.Fprintf(os.Stderr, "Error adding file to git: %v\n", err)
				return fmt.Errorf("error adding file to git: %w", err)
			}

			filename := filepath.Base(file)
			logger.Info("File %s added successfully. Committing with message: 'Track %s'", filename, filename)
			_, err = worktree.Commit("Track "+filename, &git.CommitOptions{
				Author: &object.Signature{
					Name:  "Big Chef",
					Email: "bigchef@bigchef.com",
					When:  time.Now(),
				},
			})
			if err != nil {
				logger.Error("Error committing file: %v", err)
				fmt.Fprintf(os.Stderr, "Error committing file: %v\n", err)
				return fmt.Errorf("error committing file: %w", err)
			}
			logger.Info("Successfully committed file: %s", filename)
		} else {
			logger.Info("File %s is already tracked. Restoring it to the working tree.", file)
			err := worktree.Restore(&git.RestoreOptions{
				Files:    []string{file},
				Staged:   true,
				Worktree: true,
			})
			if err != nil {
				logger.Error("Error restoring file: %v", err)
				fmt.Fprintf(os.Stderr, "Error restoring file: %v\n", err)
				return fmt.Errorf("error restoring file: %w", err)
			}
			logger.Info("File %s restored successfully", file)
		}
	}
	return nil
}