package config

import (
	"fmt"
	"os"

	"gopkg.in/yaml.v3"
)

type skillChain struct {
	Chain []string `yaml:"chain"`
}

type modelsFile struct {
	Verifier     string                `yaml:"verifier"`
	LlamaSwapURL string                `yaml:"llama_swap_url"`
	DefaultChain []string              `yaml:"default_chain"`
	Skills       map[string]skillChain `yaml:"skills"`
}

type Models struct {
	data modelsFile
}

func LoadModels(path string) (Models, error) {
	raw, err := os.ReadFile(path)
	if err != nil {
		return Models{}, fmt.Errorf("load models: %w", err)
	}
	var f modelsFile
	if err := yaml.Unmarshal(raw, &f); err != nil {
		return Models{}, fmt.Errorf("parse models: %w", err)
	}
	return Models{data: f}, nil
}

// Verifier returns the model name to use for all local-tier output verification.
func (m Models) Verifier() string { return m.data.Verifier }

// LlamaSwapURL returns the llama-swap base URL for warm-state probing.
func (m Models) LlamaSwapURL() string { return m.data.LlamaSwapURL }

// ChainFor returns the ordered list of model names for a skill.
// If override is non-empty, returns a single-entry chain (no escalation).
// Falls back to default_chain when the skill has no explicit entry.
func (m Models) ChainFor(skill, override string) []string {
	if override != "" {
		return []string{override}
	}
	if sc, ok := m.data.Skills[skill]; ok && len(sc.Chain) > 0 {
		return sc.Chain
	}
	out := make([]string, len(m.data.DefaultChain))
	copy(out, m.data.DefaultChain)
	return out
}