package config

import (
	"fmt"
	"os"

	"gopkg.in/yaml.v3"
)

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

type modelsFile struct {
	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
}

// ModelFor returns the primary model to use for a skill.
// If override is non-empty, it is returned directly.
// Falls back to default_chain[0] when the skill has no explicit entry.
func (m Models) ModelFor(skill, override string) string {
	if override != "" {
		return override
	}
	if sc, ok := m.data.Skills[skill]; ok && len(sc.Chain) > 0 {
		return sc.Chain[0]
	}
	if len(m.data.DefaultChain) > 0 {
		return m.data.DefaultChain[0]
	}
	return ""
}