package app

import (
	"context"
	"flag"
	"fmt"
	"io"
	"sort"
	"strings"

	"gitea.maximumdirect.net/eric/narratio/internal/config"
)

// Locks dispatches publish lock list and mutation helpers.
func Locks(ctx context.Context, args []string, out io.Writer) error {
	if len(args) > 0 && !strings.HasPrefix(args[0], "-") {
		switch args[0] {
		case "add":
			return LocksAdd(ctx, args[1:], out)
		case "remove":
			return LocksRemove(ctx, args[1:], out)
		default:
			return fmt.Errorf("locks: unknown subcommand %q", args[0])
		}
	}
	return LocksList(ctx, args, out)
}

// LocksList lists effective publish locks.
func LocksList(ctx context.Context, args []string, out io.Writer) error {
	fs := flag.NewFlagSet("locks", flag.ContinueOnError)
	fs.SetOutput(io.Discard)
	var flags commonConfigFlags
	addCommonConfigFlags(fs, &flags)
	if err := parseSessionAwareFlags("locks", fs, args, &flags.sessionID); err != nil {
		return err
	}
	if strings.TrimSpace(flags.sessionID) == "" {
		return fmt.Errorf("locks: session_id is required")
	}
	cfg, _, locks, _, err := loadHelperContext(ctx, flags, true)
	if err != nil {
		return fmt.Errorf("locks: %w", err)
	}
	writeLocks(out, cfg, locks)
	return nil
}

// LocksAdd adds or updates one remote lock.
func LocksAdd(ctx context.Context, args []string, out io.Writer) error {
	fs := flag.NewFlagSet("locks add", flag.ContinueOnError)
	fs.SetOutput(io.Discard)
	var flags commonConfigFlags
	var reason string
	var force bool
	addCommonConfigFlags(fs, &flags)
	fs.StringVar(&reason, "reason", "", "lock reason")
	fs.BoolVar(&force, "force", false, "update existing remote lock")
	source, err := parseSessionIDAndOnePositionalArg("locks add", "source id", fs, args, &flags.sessionID)
	if err != nil {
		return err
	}
	if strings.TrimSpace(flags.sessionID) == "" {
		return fmt.Errorf("locks add: session_id is required")
	}
	cfg, store, locks, _, err := loadHelperContext(ctx, flags, true)
	if err != nil {
		return fmt.Errorf("locks add: %w", err)
	}
	if _, err := config.ValidatePublishLockRules([]config.PublishLockRule{{Source: source}}, cfg.Pipeline.Scriptorium, cfg.Pipeline.Notarius, "locks add"); err != nil {
		return fmt.Errorf("locks add: %w", err)
	}
	if _, ok := lockSourceSet(locks.Static)[source]; ok {
		return fmt.Errorf("locks add: source %q is locked by pipeline config and cannot be modified remotely", source)
	}
	remoteSet := lockSourceSet(locks.Remote)
	if _, exists := remoteSet[source]; exists && !force {
		return fmt.Errorf("locks add: remote lock for %q already exists; pass --force to update", source)
	}
	remoteSet[source] = config.PublishLockRule{Source: source, Reason: strings.TrimSpace(reason)}
	remoteLocks := lockMapValues(remoteSet)
	if _, err := config.ValidatePublishLockRules(remoteLocks, cfg.Pipeline.Scriptorium, cfg.Pipeline.Notarius, "locks"); err != nil {
		return fmt.Errorf("locks add: %w", err)
	}
	if err := uploadRemoteLockStore(ctx, store, locks.Key, &config.PublishLockStore{Locks: remoteLocks}); err != nil {
		return fmt.Errorf("locks add: %w", err)
	}
	_, err = fmt.Fprintf(out, "narratio session locks add: locked %s\n", source)
	return err
}

// LocksRemove removes one remote lock.
func LocksRemove(ctx context.Context, args []string, out io.Writer) error {
	fs := flag.NewFlagSet("locks remove", flag.ContinueOnError)
	fs.SetOutput(io.Discard)
	var flags commonConfigFlags
	addCommonConfigFlags(fs, &flags)
	source, err := parseSessionIDAndOnePositionalArg("locks remove", "source id", fs, args, &flags.sessionID)
	if err != nil {
		return err
	}
	if strings.TrimSpace(flags.sessionID) == "" {
		return fmt.Errorf("locks remove: session_id is required")
	}
	cfg, store, locks, _, err := loadHelperContext(ctx, flags, true)
	if err != nil {
		return fmt.Errorf("locks remove: %w", err)
	}
	if _, err := config.ValidatePublishLockRules([]config.PublishLockRule{{Source: source}}, cfg.Pipeline.Scriptorium, cfg.Pipeline.Notarius, "locks remove"); err != nil {
		return fmt.Errorf("locks remove: %w", err)
	}
	remoteSet := lockSourceSet(locks.Remote)
	if _, ok := remoteSet[source]; !ok {
		if _, static := lockSourceSet(locks.Static)[source]; static {
			return fmt.Errorf("locks remove: source %q is locked by pipeline config and cannot be unlocked remotely", source)
		}
		return fmt.Errorf("locks remove: remote lock for %q does not exist", source)
	}
	delete(remoteSet, source)
	remoteLocks := lockMapValues(remoteSet)
	if err := uploadRemoteLockStore(ctx, store, locks.Key, &config.PublishLockStore{Locks: remoteLocks}); err != nil {
		return fmt.Errorf("locks remove: %w", err)
	}
	_, err = fmt.Fprintf(out, "narratio session locks remove: unlocked %s\n", source)
	return err
}

func writeLocks(out io.Writer, cfg *config.Config, locks *effectiveLocks) {
	if locks == nil || len(locks.All) == 0 {
		fmt.Fprintln(out, "Publish locks: none")
		return
	}
	fmt.Fprintln(out, "Publish locks:")
	published := map[string]config.PublishOutputRule{}
	if cfg != nil && cfg.Pipeline != nil && cfg.Pipeline.Publish != nil {
		for _, rule := range cfg.Pipeline.Publish.Outputs {
			published[strings.TrimSpace(rule.Source)] = rule
		}
	}
	staticSet := lockSourceSet(locks.Static)
	for _, lock := range locks.All {
		origin := "remote"
		if _, ok := staticSet[lock.Source]; ok {
			origin = "pipeline"
		}
		promo := "not-published"
		if _, ok := published[lock.Source]; ok {
			promo = "published"
		}
		reason := strings.TrimSpace(lock.Reason)
		if reason == "" {
			reason = "(no reason)"
		}
		fmt.Fprintf(out, "- %s origin=%s %s reason=%s\n", lock.Source, origin, promo, reason)
	}
}

func lockMapValues(in map[string]config.PublishLockRule) []config.PublishLockRule {
	keys := make([]string, 0, len(in))
	for key := range in {
		keys = append(keys, key)
	}
	sort.Strings(keys)
	out := make([]config.PublishLockRule, 0, len(keys))
	for _, key := range keys {
		item := in[key]
		item.Source = key
		item.Reason = strings.TrimSpace(item.Reason)
		out = append(out, item)
	}
	return out
}