package hooks

import (
	"context"
	"errors"

	"github.com/google/uuid"
)

// ErrBuiltinReadOnly is returned by Update/Delete when a caller attempts to
// modify a row with source='builtin' beyond toggling `enabled`. Builtin rows
// are canonical — content comes from embedded JS at every startup (Phase 04
// seed). UI should render them read-only except for the enabled toggle.
// Message is surfaced via i18n key hook.builtin_readonly.
var ErrBuiltinReadOnly = errors.New("hook: builtin row is read-only except enabled toggle")

// seedBypassKey is the private context key used by Phase 04 builtin seeder to
// bypass the Update/Delete builtin-readonly guard. Process-private: only the
// seeder sets it. Ensures user-facing writes still fail ErrBuiltinReadOnly.
type seedBypassKey struct{}

// WithSeedBypass marks ctx as originating from the builtin seeder. Store
// implementations MUST consult IsSeedBypass(ctx) before rejecting writes on
// builtin rows. Any other caller is denied.
func WithSeedBypass(ctx context.Context) context.Context {
	return context.WithValue(ctx, seedBypassKey{}, true)
}

// IsSeedBypass reports whether ctx carries the builtin-seeder bypass marker.
func IsSeedBypass(ctx context.Context) bool {
	v, _ := ctx.Value(seedBypassKey{}).(bool)
	return v
}

// ListFilter narrows results from HookStore.List.
type ListFilter struct {
	TenantID *uuid.UUID
	AgentID  *uuid.UUID
	Event    *HookEvent
	Scope    *Scope
	Enabled  *bool
}

// HookStore is the data-access contract for agent hooks.
// PG impl lives in internal/store/pg/hooks.go;
// SQLite impl lives in internal/store/sqlitestore/hooks.go.
//
// All write operations must enforce tenant isolation: reads outside master scope
// must include WHERE tenant_id = $N. See store.IsMasterScope(ctx).
type HookStore interface {
	// Create inserts a new hook config and returns the generated UUID.
	Create(ctx context.Context, cfg HookConfig) (uuid.UUID, error)

	// GetByID returns a single hook config by primary key.
	// Returns nil, nil when not found (no sentinel error).
	GetByID(ctx context.Context, id uuid.UUID) (*HookConfig, error)

	// List returns hooks matching the filter. Caller applies ordering/limit.
	List(ctx context.Context, filter ListFilter) ([]HookConfig, error)

	// Update applies the map of column→value patches and bumps the version field.
	// Callers must not include "version" in updates — the store increments it
	// atomically to bust the TTL cache entry (H1 mitigation).
	Update(ctx context.Context, id uuid.UUID, updates map[string]any) error

	// Delete removes a hook config. hook_executions rows are preserved via
	// ON DELETE SET NULL on the hook_id FK column.
	Delete(ctx context.Context, id uuid.UUID) error

	// ResolveForEvent returns the ordered list of enabled hooks that match
	// (tenant_id, agent_id, event). Implementations should cache this result
	// with a short TTL (5s) keyed by (tenant_id, agent_id, event, maxVersion)
	// and short-circuit via COUNT(*) = 0 cache for the zero-hooks hot path.
	ResolveForEvent(ctx context.Context, event Event) ([]HookConfig, error)

	// WriteExecution appends an immutable execution audit row.
	// Caller must pre-truncate Error to 256 chars and encrypt ErrorDetail.
	WriteExecution(ctx context.Context, exec HookExecution) error

	// SetHookAgents replaces all junction rows for hookID with the given agentIDs.
	SetHookAgents(ctx context.Context, hookID uuid.UUID, agentIDs []uuid.UUID) error

	// GetHookAgents returns the agent UUIDs linked to hookID via the junction table.
	GetHookAgents(ctx context.Context, hookID uuid.UUID) ([]uuid.UUID, error)
}