package jobspec

import (
	"fmt"
	"os"
	"strings"

	"github.com/hashicorp/hcl/v2"
	"github.com/hashicorp/hcl/v2/gohcl"
	"github.com/hashicorp/hcl/v2/hclsimple"
)

type Spec struct {
	Job   JobSpec    `hcl:"job,block"`
	Tasks []TaskSpec `hcl:"task,block"`
}

type JobSpec struct {
	Name string `hcl:"name,label"`
	Type string `hcl:"type,optional"`
}

type TaskSpec struct {
	Name    string   `hcl:"name,label"`
	Command string   `hcl:"command"`
	Args    []string `hcl:"args,optional"`
	Env     []string `hcl:"env,optional"`
}

func ParseFile(path string) (*Spec, error) {
	data, err := os.ReadFile(path)
	if err != nil {
		return nil, fmt.Errorf("read spec file: %w", err)
	}
	return Parse(data, path)
}

func Parse(data []byte, filename string) (*Spec, error) {
	var spec Spec
	err := hclsimple.Decode(filename, data, nil, &spec)
	if err != nil {
		return nil, fmt.Errorf("decode hcl: %w", err)
	}
	if spec.Job.Name == "" {
		return nil, fmt.Errorf("spec missing job name")
	}
	if len(spec.Tasks) == 0 {
		return nil, fmt.Errorf("spec must have at least one task")
	}
	for i, t := range spec.Tasks {
		if t.Command == "" {
			return nil, fmt.Errorf("task[%d] (%s) missing command", i, t.Name)
		}
	}
	return &spec, nil
}

func (s *Spec) Validate() error {
	if strings.TrimSpace(s.Job.Name) == "" {
		return fmt.Errorf("job name is required")
	}
	if len(s.Tasks) == 0 {
		return fmt.Errorf("at least one task is required")
	}
	return nil
}

var _ = hcl.Diagnostics{}
var _ = gohcl.DecodeBody