// Package tools is executus's library of generic, host-agnostic agent tools.
//
// A host registers the tools it wants against a tool.Registry, then runs an
// agent whose RunnableAgent.LowLevelTools name them. Tools split two ways:
//
//   - Always-available, zero-configuration tools register via Register (think,
//     now, cite) — all nil-safe, so a light host (gadfly) calls Register and is
//     immediately useful.
//   - Backed tools take a nil-safe Deps describing their host backend and
//     register via grouped registrars (RegisterMeta, and RegisterWeb/Store/…
//     as they land). Each Deps ships sensible defaults so "some setup" is small.
//
// A host adds its own domain tools against the SAME registry.
package tools

import (
	"context"
	"errors"

	"gitea.stevedudenhoeffer.com/steve/executus/llmmeta"
	"gitea.stevedudenhoeffer.com/steve/executus/tool"
)

// Register adds the always-available, zero-configuration generic tools:
//
//   - think  — record a thought to the run trace (no external effect)
//   - now    — current time (UTC unless a CurrentTimeProvider is wired)
//   - cite   — record a source citation (inert unless a CitationStorage is wired)
//
// All are nil-safe. Returns the first registration error.
func Register(reg tool.Registry) error {
	return registerAll(reg,
		NewThink(),
		NewNow(nil),
		NewCite(nil),
	)
}

// MetaDeps wires the LLM-backed meta tools (classify, extract_entities,
// summarize). Helper is required. Budget defaults to an in-memory per-run cap;
// Files is optional (summarize's file_id input is inert without it); MaxPerRun
// and MaxWords default when non-positive.
type MetaDeps struct {
	Helper    *llmmeta.Helper
	Budget    SearchBudget
	Files     FileStorage
	MaxPerRun int // per-run cap for each meta tool; default 10
	MaxWords  int // summarize length cap; default 200
}

// RegisterMeta adds classify, extract_entities, and summarize. It requires a
// configured llmmeta.Helper (the fast-tier meta-LLM caller); everything else
// defaults.
func RegisterMeta(reg tool.Registry, d MetaDeps) error {
	if d.Helper == nil {
		return errors.New("tools: MetaDeps.Helper is required for the meta tools")
	}
	if d.MaxPerRun <= 0 {
		d.MaxPerRun = 10
	}
	if d.MaxWords <= 0 {
		d.MaxWords = 200
	}
	if d.Budget == nil {
		// Build the default budget WITH the configured per-run cap so
		// MetaDeps.MaxPerRun is honored — an empty caps map would fall back to
		// the budget's hardcoded default and silently ignore MaxPerRun.
		d.Budget = NewInMemorySearchBudget(map[string]int{
			"classify":         d.MaxPerRun,
			"extract_entities": d.MaxPerRun,
			"summarize":        d.MaxPerRun,
		})
	}
	cfg := fixedMetaConfig{maxPerRun: d.MaxPerRun, maxWords: d.MaxWords}
	return registerAll(reg,
		NewClassify(d.Helper, cfg, d.Budget),
		NewExtractEntities(d.Helper, cfg, d.Budget),
		NewSummarize(d.Helper, cfg, d.Budget, d.Files),
	)
}

func registerAll(reg tool.Registry, ts ...tool.Tool) error {
	for _, t := range ts {
		if err := reg.Register(t); err != nil {
			return err
		}
	}
	return nil
}

// fixedMetaConfig satisfies ClassifyConfig / ExtractEntitiesConfig /
// SummarizeConfig with static caps read from MetaDeps.
type fixedMetaConfig struct{ maxPerRun, maxWords int }

func (c fixedMetaConfig) MaxPerRun(context.Context) int { return c.maxPerRun }
func (c fixedMetaConfig) MaxWords(context.Context) int  { return c.maxWords }