package main

import (
	"context"
	"errors"
	"fmt"
	"log/slog"
	"net/http"
	"os"
	"os/signal"
	"path/filepath"
	"syscall"

	"github.com/spf13/cobra"
	"go.bigb.es/auxilia/scribe"

	"sourcecraft.dev/bigbes/lethe/internal/collector/config"
	"sourcecraft.dev/bigbes/lethe/internal/collector/ingest"
	"sourcecraft.dev/bigbes/lethe/internal/collector/parser"
	"sourcecraft.dev/bigbes/lethe/internal/collector/parser/claudecode"
	"sourcecraft.dev/bigbes/lethe/internal/collector/parser/opencode"
	"sourcecraft.dev/bigbes/lethe/internal/collector/state"
)

func main() {
	if err := newRootCmd().Execute(); err != nil {
		os.Exit(1)
	}
}

func defaultConfigPath() string {
	home, err := os.UserHomeDir()
	if err != nil {
		return "~/.config/lethe/collector.yaml"
	}
	return filepath.Join(home, ".config", "lethe", "collector.yaml")
}

func newRootCmd() *cobra.Command {
	var configPath string

	root := &cobra.Command{
		Use:   "lethe-collector",
		Short: "Ingest assistant transcripts into lethe",
	}
	root.PersistentFlags().StringVar(&configPath, "config", defaultConfigPath(), "path to collector config file")

	root.AddCommand(
		newDaemonCmd(&configPath),
		newBackfillCmd(&configPath),
		newStatusCmd(&configPath),
	)

	return root
}

func newDaemonCmd(configPath *string) *cobra.Command {
	return &cobra.Command{
		Use:   "daemon",
		Short: "Run the collector daemon",
		RunE: func(cmd *cobra.Command, args []string) error {
			cfg, err := config.Load(*configPath)
			if err != nil {
				return fmt.Errorf("load config: %w", err)
			}

			logger, err := buildLogger(cfg.Log.Level, cfg.Log.Format)
			if err != nil {
				return fmt.Errorf("setup logger: %w", err)
			}
			slog.SetDefault(logger)

			ctx, stop := signal.NotifyContext(context.Background(), syscall.SIGINT, syscall.SIGTERM)
			defer stop()

			store, err := state.Open(ctx, filepath.Join(cfg.StateDir, "state.db"))
			if err != nil {
				return fmt.Errorf("open state: %w", err)
			}
			defer store.Close()

			client := &http.Client{Timeout: cfg.HTTP.Timeout}
			sender := ingest.NewSender(cfg.ServerURL, client)

			parsers := buildParsers(cfg.Host)

			return ingest.RunDaemon(ctx, *cfg, parsers, store, sender)
		},
	}
}

func newBackfillCmd(configPath *string) *cobra.Command {
	return &cobra.Command{
		Use:   "backfill <tool>",
		Short: "One-shot ingest for a specific tool",
		Args:  cobra.ExactArgs(1),
		RunE: func(cmd *cobra.Command, args []string) error {
			tool := args[0]

			cfg, err := config.Load(*configPath)
			if err != nil {
				return fmt.Errorf("load config: %w", err)
			}

			ctx := cmd.Context()

			store, err := state.Open(ctx, filepath.Join(cfg.StateDir, "state.db"))
			if err != nil {
				return fmt.Errorf("open state: %w", err)
			}
			defer store.Close()

			client := &http.Client{Timeout: cfg.HTTP.Timeout}
			sender := ingest.NewSender(cfg.ServerURL, client)

			parsers := buildParsers(cfg.Host)
			p, ok := parsers[tool]
			if !ok {
				return fmt.Errorf("no parser registered for tool %q", tool)
			}

			var matched int
			var errs []error
			for _, src := range cfg.Sources {
				if src.Tool != tool {
					continue
				}
				matched++
				if err := ingest.RunBackfillOnce(ctx, *cfg, src, p, store, sender); err != nil {
					errs = append(errs, fmt.Errorf("backfill %s (%s): %w", src.Tool, src.Path, err))
				}
			}

			if matched == 0 {
				return fmt.Errorf("no configured source for tool %q", tool)
			}

			if len(errs) > 0 {
				return fmt.Errorf("backfill completed with errors: %w", errors.Join(errs...))
			}

			return nil
		},
	}
}

func newStatusCmd(configPath *string) *cobra.Command {
	return &cobra.Command{
		Use:   "status",
		Short: "Print collector status",
		RunE: func(cmd *cobra.Command, args []string) error {
			cfg, err := config.Load(*configPath)
			if err != nil {
				return fmt.Errorf("load config: %w", err)
			}

			ctx := cmd.Context()

			store, err := state.Open(ctx, filepath.Join(cfg.StateDir, "state.db"))
			if err != nil {
				return fmt.Errorf("open state: %w", err)
			}
			defer store.Close()

			stats, err := store.Stats(ctx)
			if err != nil {
				return fmt.Errorf("get stats: %w", err)
			}

			fmt.Printf("host:           %s\n", cfg.Host)
			fmt.Printf("server_url:     %s\n", cfg.ServerURL)
			fmt.Printf("state_db:       %s\n", filepath.Join(cfg.StateDir, "state.db"))
			fmt.Printf("outbox_rows:    %d\n", stats.OutboxCount)
			fmt.Printf("outbox_bytes:   %d\n", stats.OutboxBytes)
			fmt.Printf("source_offsets: %d\n", stats.SourceOffsets)
			fmt.Println()

			parsers := buildParsers(cfg.Host)

			for _, src := range cfg.Sources {
				fmt.Printf("source: %s (%s)\n", src.Tool, src.Path)

				p, ok := parsers[src.Tool]
				if !ok {
					fmt.Printf("  offset: N/A (no parser for %s)\n", src.Tool)
					continue
				}

				files, err := p.Discover(src.Path)
				if err != nil {
					fmt.Printf("  discover error: %v\n", err)
					continue
				}

				if len(files) == 0 {
					fmt.Printf("  (no files found)\n")
					continue
				}

				for _, f := range files {
					off, err := store.GetOffset(ctx, src.Tool, f.Path)
					if err != nil {
						fmt.Printf("  %s: error=%v\n", f.Path, err)
						continue
					}
					lagBytes := f.Size - off
					if lagBytes < 0 {
						lagBytes = 0
					}
					fmt.Printf("  %s: offset=%d lag_bytes=%d\n", f.Path, off, lagBytes)
				}
			}

			return nil
		},
	}
}

func buildParsers(host string) map[string]parser.Parser {
	return map[string]parser.Parser{
		"claude-code": claudecode.New(host),
		"opencode":    opencode.New(host),
	}
}

func buildLogger(levelStr, format string) (*slog.Logger, error) {
	var level slog.Level
	switch levelStr {
	case "debug":
		level = slog.LevelDebug
	case "info":
		level = slog.LevelInfo
	case "warn":
		level = slog.LevelWarn
	case "error":
		level = slog.LevelError
	default:
		return nil, fmt.Errorf("unknown log level %q", levelStr)
	}

	var handler slog.Handler
	switch format {
	case "tint":
		handler = scribe.NewTintHandler(
			scribe.WithWriter(os.Stderr),
			scribe.WithLevel(level),
		)
	case "json":
		handler = slog.NewJSONHandler(os.Stderr, &slog.HandlerOptions{Level: level})
	case "human":
		handler = slog.NewTextHandler(os.Stderr, &slog.HandlerOptions{Level: level})
	default:
		return nil, fmt.Errorf("unknown log format %q", format)
	}

	return slog.New(handler), nil
}