package cmd

import (
	"context"
	"fmt"
	"os"

	"git.jnss.me/joakim/opal/internal/engine"
	"github.com/spf13/cobra"
)

// ParsedArgs represents preprocessed command arguments
type ParsedArgs struct {
	Command   string
	Filters   []string
	Modifiers []string
}

// Context key for parsed args
type contextKey string

const parsedArgsKey contextKey = "parsedArgs"

// Global flags
var (
	configDirFlag string
	dataDirFlag   string
)

// Command classification
var commandNames = []string{
	"add", "done", "modify", "delete",
	"start", "stop", "count", "projects", "tags",
	"info", "edit", "server", "sync", "reports", "setup",
}

// Report names (dynamically populated)
var reportNames = []string{
	"active", "all", "completed", "list", "minimal",
	"newest", "next", "oldest", "overdue", "ready", "recurring",
	"template", "waiting",
}

var commandsWithModifiers = map[string]bool{
	"add":    true,
	"modify": true,
}

var rootCmd = &cobra.Command{
	Use:   "opal",
	Short: "Opal task manager - taskwarrior-inspired CLI task management",
	Long: `Opal is a powerful command-line task manager inspired by taskwarrior.
It supports filtering, tags, priorities, projects, and recurring tasks.`,
	Run: func(cmd *cobra.Command, args []string) {
		// Default behavior: run configured default report (defaults to "list")
		parsed := getParsedArgs(cmd)

		// Get default report from config
		cfg, err := engine.GetConfig()
		if err != nil {
			fmt.Fprintf(os.Stderr, "Error loading config: %v\n", err)
			os.Exit(1)
		}

		defaultReport := cfg.DefaultReport
		if defaultReport == "" {
			defaultReport = "list"
		}

		if err := runReport(defaultReport, parsed.Filters); err != nil {
			fmt.Fprintf(os.Stderr, "Error: %v\n", err)
			os.Exit(1)
		}
	},
}

func Execute() error {
	// Check for help flags/command BEFORE preprocessing
	// This allows Cobra to handle help naturally for the root command
	if len(os.Args) > 1 {
		firstArg := os.Args[1]
		if firstArg == "-h" || firstArg == "--help" || firstArg == "help" {
			// Let Cobra handle help - skip preprocessing
			return rootCmd.Execute()
		}
	}

	// Preprocess arguments BEFORE Cobra routing
	if len(os.Args) > 1 {
		parsed := preprocessArgs(os.Args[1:])

		// Store in context for commands to use
		ctx := context.WithValue(context.Background(), parsedArgsKey, parsed)
		rootCmd.SetContext(ctx)

		// Rewrite os.Args for Cobra based on parsed command
		// This allows Cobra to route to the correct command
		if parsed.Command != "list" || len(parsed.Filters) > 0 || len(parsed.Modifiers) > 0 {
			// Reconstruct args: [command, ...filters, ...modifiers]
			newArgs := []string{os.Args[0], parsed.Command}
			newArgs = append(newArgs, parsed.Filters...)
			newArgs = append(newArgs, parsed.Modifiers...)
			os.Args = newArgs
		}
	}

	return rootCmd.Execute()
}

// getParsedArgs retrieves preprocessed args from context
func getParsedArgs(cmd *cobra.Command) *ParsedArgs {
	if v := cmd.Context().Value(parsedArgsKey); v != nil {
		if parsed, ok := v.(*ParsedArgs); ok {
			return parsed
		}
	}
	return &ParsedArgs{}
}

// preprocessArgs parses command-line arguments before Cobra routing
// Returns: command name, filters, modifiers
func preprocessArgs(args []string) *ParsedArgs {
	if len(args) == 0 {
		return &ParsedArgs{
			Command:   "list", // Default command
			Filters:   []string{},
			Modifiers: []string{},
		}
	}

	// Find command position (check both regular commands and reports)
	cmdIdx := -1
	cmdName := ""

	for i, arg := range args {
		// Check regular commands
		for _, name := range commandNames {
			if arg == name {
				cmdIdx = i
				cmdName = name
				break
			}
		}
		// Check report names
		if cmdIdx < 0 {
			for _, name := range reportNames {
				if arg == name {
					cmdIdx = i
					cmdName = name
					break
				}
			}
		}
		if cmdIdx >= 0 {
			break
		}
	}

	// If no command found, treat as filters for default list command
	if cmdIdx == -1 {
		return &ParsedArgs{
			Command:   "list",
			Filters:   args,
			Modifiers: []string{},
		}
	}

	// Split arguments around command
	leftArgs := args[:cmdIdx] // Everything before command
	rightArgs := []string{}
	if cmdIdx+1 < len(args) {
		rightArgs = args[cmdIdx+1:] // Everything after command
	}

	// Determine how to interpret right args
	if commandsWithModifiers[cmdName] {
		// Command accepts modifiers
		// Left = filters, Right = modifiers
		return &ParsedArgs{
			Command:   cmdName,
			Filters:   leftArgs,
			Modifiers: rightArgs,
		}
	} else {
		// Command doesn't accept modifiers
		// Both left and right are filters
		allFilters := append(leftArgs, rightArgs...)
		return &ParsedArgs{
			Command:   cmdName,
			Filters:   allFilters,
			Modifiers: []string{},
		}
	}
}

func init() {
	// Add persistent flags for directory overrides
	rootCmd.PersistentFlags().StringVar(&configDirFlag, "config-dir", "",
		"Config directory (default: $XDG_CONFIG_HOME/opal or ~/.config/opal)")
	rootCmd.PersistentFlags().StringVar(&dataDirFlag, "data-dir", "",
		"Data directory (default: $XDG_DATA_HOME/opal or ~/.local/share/opal)")

	// Use PersistentPreRun for initialization (runs for all subcommands unless overridden)
	rootCmd.PersistentPreRun = func(cmd *cobra.Command, args []string) {
		initializeApp()
	}

	// Add regular subcommands
	rootCmd.AddCommand(addCmd)
	rootCmd.AddCommand(doneCmd)
	rootCmd.AddCommand(modifyCmd)
	rootCmd.AddCommand(deleteCmd)
	rootCmd.AddCommand(startCmd)
	rootCmd.AddCommand(stopCmd)
	rootCmd.AddCommand(countCmd)
	rootCmd.AddCommand(projectsCmd)
	rootCmd.AddCommand(tagsCmd)
	rootCmd.AddCommand(infoCmd)
	rootCmd.AddCommand(editCmd)
	rootCmd.AddCommand(reportsCmd)

	// Add report commands dynamically
	reportCommands := CreateReportCommands()
	for _, cmd := range reportCommands {
		rootCmd.AddCommand(cmd)
	}
}

func initializeApp() {
	// Set directory overrides from flags if provided
	if configDirFlag != "" {
		engine.SetConfigDirOverride(configDirFlag)
	}
	if dataDirFlag != "" {
		engine.SetDataDirOverride(dataDirFlag)
	}

	// Check for first run (before initializing DB/config)
	isFirstRun := engine.IsFirstRun()

	// Initialize database
	if err := engine.InitDB(); err != nil {
		fmt.Fprintf(os.Stderr, "Error initializing database: %v\n", err)
		os.Exit(1)
	}

	// On first run, create the config file with defaults
	if isFirstRun {
		if err := engine.InitConfig(); err != nil {
			fmt.Fprintf(os.Stderr, "Error creating config: %v\n", err)
			os.Exit(1)
		}
		showFirstRunMessage()
	}

	// Load config (reads file if present, otherwise uses defaults)
	if _, err := engine.LoadConfig(); err != nil {
		fmt.Fprintf(os.Stderr, "Error loading config: %v\n", err)
		os.Exit(1)
	}
}

func showFirstRunMessage() {
	fmt.Fprintln(os.Stderr, "")
	fmt.Fprintln(os.Stderr, "👋 Welcome to Opal Task Manager!")
	fmt.Fprintln(os.Stderr, "")
	fmt.Fprintln(os.Stderr, "Default configuration created. To customize your setup,")
	fmt.Fprintln(os.Stderr, "run: opal setup")
	fmt.Fprintln(os.Stderr, "")
}